Diesel Engine Fundamentals | SaVRee 3D | Skillshare
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51 Lessons (4h 57m)
    • 1. Course Overview

      2:23
    • 2. Welcome To The Course

      1:13
    • 3. Short History Lesson

      3:39
    • 4. Diesel Engines Introduction

      3:31
    • 5. Diesel and Gasoline Engine Comparison

      8:43
    • 6. Free Resources Note

      1:39
    • 7. Major Diesel Engine Components

      3:02
    • 8. Cylinder Block

      3:33
    • 9. Crankcase and Oil Pan

      14:11
    • 10. Cylinder Sleeve Or Bore

      5:43
    • 11. Straight and V Line

      2:57
    • 12. Piston and Piston Rings

      10:40
    • 13. Four and Two Stroke Lubrication Oil Systems

      4:08
    • 14. Connecting Rod

      9:22
    • 15. Crankshaft

      10:11
    • 16. White Metal Bearing

      6:12
    • 17. Flywheel

      8:32
    • 18. Cylinder Head

      7:36
    • 19. Intake and Exhaust Valves

      2:55
    • 20. Timing Gears, Camshafts and Valve Mechanism

      19:05
    • 21. Blower

      5:01
    • 22. Diesel Engine Support Systems

      7:18
    • 23. Engine Cooling

      1:16
    • 24. How Engine Cooling Water Systems Work

      13:10
    • 25. Engine Lubrication

      7:44
    • 26. How Lubrication Oil Filters Work

      9:51
    • 27. Fuel System

      14:55
    • 28. Charging and Scavenging

      4:52
    • 29. Air Intake System

      9:32
    • 30. Turbocharging

      4:04
    • 31. How Turbochargers Work

      15:02
    • 32. Supercharging

      1:18
    • 33. Exhaust System

      3:43
    • 34. Operational Terminology

      0:33
    • 35. Spark and Compression Ignition Engines

      1:29
    • 36. Bore and Stroke

      0:57
    • 37. Engine Displacement

      1:18
    • 38. Degree of Crankshaft Rotation

      3:44
    • 39. Firing Order

      2:03
    • 40. Compression Ratio and Clearance Volume

      2:36
    • 41. Horsepower

      3:49
    • 42. Fundamentals of the Diesel Cycle

      0:35
    • 43. The Basic Diesel Cycles

      4:13
    • 44. Timing

      1:57
    • 45. The Four Stroke Cycle

      2:09
    • 46. How Four Stroke Engines Work

      9:01
    • 47. The Two Stroke Cycle

      1:09
    • 48. How Two Stroke Engines Work

      12:50
    • 49. Final Thoughts

      1:07
    • 50. BONUS How A Centrifugal Governor Works

      8:16
    • 51. BONUS How Spark Plugs Work

      12:35
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About This Class

Without exception, the reciprocating piston engine is the most influential machine ever invented by mankind. From its early beginnings as a steam engine, the piston engine has revolutionised the way we live, work and travel. This course will teach you about this truly amazing machine.

You will learn:

  • How An Engine Works

  • How Two Stroke and Four Stroke Engines Work

  • The Difference Between Petrol/Gasoline and Diesel Engines

  • Engine Components (Piston Rings, Rocker Arms, Valves etc.)

  • Engine Systems (Water, Oil, Air, Exhaust and Electrical)

  • Engine Terminology (BDC, TDC, Firing Order etc.)

  • How Engine Ancillaries Work (Turbocharger, Supercharger etc.)

  • And a lot lot more!

*** Note that this course focuses more on the diesel fired engine type rather than the petrol/gasoline type, but gives a general good overview concerning the internal combustion (IC) engine. The video is part of the Mechanical Engineering video series.***

The course is designed to take you from zero to hero concerning combustion engine knowledge. Even if you already have some background knowledge, this course will serve as an efficient refresher. Whatever your level of understanding, or engineering background (oil and gas, marine, power etc.), I can guarantee you will have never taken an engineering course like this one (unless you have taken one of my other courses!).

Interactive 3D models are used extensively to show you each individual engine component and how components work together to complete useful work. 

The course is packed with 2D images, 2D animations and 3D animations.

Written content has been read aloud so that you can 'learn on the go' without needing to watch the screen constantly.

Don't forget to download the free PDF that is attached, it gives you access to over 30 interactive 3D models that you can use to consolidate what you have learnt!

Don't waste more time reading this course description, check-out the course! :)

Regards,

Jon 

saVRee.com

Transcripts

1. Course Overview: in this course, you're going to learn about one of the most influential machines ever invented the diesel engine. Now you might be thinking that diesel engines are not really as important as petrol engines , but you'd be wrong. Pretty much every modern and large internal combustion engine is, in fact, a diesel engine. Some cars and trucks of diesel engines, trains of diesel engines, ships up diesel engines and even tanks have diesel engines. But what is it about this remarkable machine that makes it suitable for so many different and varying applications? What are its main components? How does it work on What's the difference between a supercharger on a turbocharger? Well, in this course, we're going to answer all of these questions and many, many more. You're going to learn how to stroke and four stroke engines work, what the difference between petrol and diesel engines are and how to visually identify it's type. You'll learn all of the combustion engines, main components as well as what they do and why. Well, look at different engine systems that required to keep the engine running. This includes the water, oil, air exhausts and electrical systems. You'll learn some engine theory and cover topics such as bottom and top, dead centre displacement, firing order and degrees of rotation on Well, look engine ancillary is such as cooling water pumps the turbocharger supercharger. But this is just some of the content. In this 4.5 hour long course, I'll be using interactive three D models and animations to show you the entire engine will take cross sections of various machinery. Items on will explode the machinery items out into their individual components so that we can really understand what exactly is happening and how so. If you're a newbie engineer or an old hand, or maybe you just want to broaden your engineering knowledge, this course is definitely for you. Because irrespective of where you go in the world or what you do at these Lynn Gin is never far away. My name is John Russell, and I'll be your instructor for this course. I hope to see you on it. 2. Welcome To The Course: Hi, John here. I just wanted to do a short video just to say thank you very much for purchasing this course. This is a welcome video of put in all of my courses, and it's just a way of saying thank you. I know there's a 1,000,001 other things that you could be doing with your time right now on the fact that you've taken time out on actually spent some money to purchases, course and invested time it takes to learn from it is really great and trauma say thanks. The other reason I want to say thank you is because your purchase helps me personally produce more more content on this is something that I really enjoy. I enjoy helping people learn. I enjoy teaching. A new perch in this course helps me continue. So without further ado, let's start the course. Its get stuck right in. I really hope you enjoy it. If you've got any feedback, please do let me know because this is really valuable. It helps me improve the course, the courses in static. I'm going to continue to improve it, change things on feedback is always, always welcome. 20 questions then, please, do you shoot them off to me? I'll answer them as quickly and thoroughly as I can. Great. Thanks very much for your time. 3. Short History Lesson: history. The modern diesel engine came about as the result of the internal combustion principles first proposed by Saidi Karna in the early 19th century, Dr Rudolf Diesel applied side incarnates principles into a patented cycle or method of combustion. There's became known as the diesel cycle. His patented engine operated when the heat generated during the compression of the air fuel charge cause ignition off the mixture, which then expanded at a constant pressure. During the full power stroke of the engine, Dr Diesels first engine run on coal dust and used a compression pressure of 1500 PS I to increase its theoretical efficiency. His first engine did no have provision for any type of cooling system. Consequently, between the extreme pressure and the lack of cooling, the engine exploded and almost killed its inventor. After recovering from his injuries, diesel tried again. Using oil is the fuel, adding the cooling water jacket around the cylinder on low in the compression ratio to approximately 550 p. S I. This combination eventually proves successful production rights to the engine was sold to Adolphus Busch, who built the first diesel engines for commercial use, installing them in his ST Louis brewery to drive various pumps so we can see even back then that these Lincoln was being used to drive pumps in a brewery on Dr. Diesel actually was trained in Munich, and he used to work in the city next to Munich called Alex Berg. Now I was fortunate enough to visit Alex Berg when I was inspecting a hydro electric power station and I visited a water pumping house in Aldeburgh that dates back to about 150 years ago. Now, when I was in this water pump house, I noticed that the water pumps themselves were very similar to a piston engine or internal combustion engine, with the big difference being that this punk that used to pump up water from the river to the city was used for water, and it was not used for combustion. However, the guy told me that he was highly likely that Rudolf Diesel had been to the pump house and he'd seen these pumps on. It was quite probable that this was his inspiration for the diesel engine. Now I've seen the piston pumps that they have in Augsburg, and I think it's definitely probable that he got his inspiration from these pumps there, more or less piston pumps ons use only need to change the design slightly in order to get a combustion engine. My doctor Diesel was trained in Munich. He knew a lot about Thermo dynamics and combustion, and I'm pretty sure you figured out very quickly how to change the design slightly in order that you could use it as a power generation machine or as a prime move up. He also used to work in the man factory or the M A N factory. That's Munich. Alex Bogan, Nuremberg. You may even see man today because their trucks are world wide. That's predominately what they produce very large trucks and sometimes buses. So have you ever see them? M am you nickelsburg Nuremberg on, then a bit of history. You'll know that Dr Diesel used to work there, and that is where he invented the diesel engine. I should also mention that a man predominantly earn a lot of money in the shipping industry because they produce very large to stroke diesel engines, and they've been doing that for over 100 years now. So anyway, that's a sure history lesson concerning Rudolf Diesel on how the diesel engine was first invented 4. Diesel Engines Introduction: diesel engines. Introduction Most industrial facilities require some type of prime mover to supply mechanical power for pumping electrical power generation operation of heavy equipment and to act as a backup electrical generator for emergency use during the loss of the normal power source. Although several types of prime mover available gasoline engines steam gas turbines, the diesel engine is the most commonly used. Diesel engines provide a self reliant energy source that is available in sizes from a few horsepower to 10,000 hp. Relatively speaking diesel engines. A small, inexpensive, powerful fuel efficient on extremely reliable if maintained properly. Because otherwise, produce of these legends at industrial facilities basic understanding of the operation of a diesel engine were helping. Sure they are operated and maintained properly due to a large variety of sizes, brands and types of engines in service. This course is intended to provide the fundamentals and theory of operation of a diesel engine. Specific information on a particular engine should be obtained from the original equipment manufacturer Will the ODM. So this is a short introduction about the diesel engine, as I've already stated in the landing page video or the video that you perhaps saw prior to opening. Approaching this course, diesel engines are used all over the place. They're used for sprinkler pumps, and that is because you need a diesel motor to power. The sprinkler pump were at least to rotate the sprinkler pump in the event of power loss. But you'll see this very often in a lot of facilities where you have safety, critical processes or environments in a hospital, for example, you're also gonna have a diesel engine on this diesel engine. Is there to supply electricity to the hospital in the event of power loss? Many industrial facilities are the same. They also have backup diesel generators or emergency diesel generators. And the reason is quite simple. If we have a plan such as one in the all seed industry, they use a lot of heck. Sane or heck seems quite flammable andan the event of power loss. They might have to vent the heck sane, or at least keep the fans running for out the building to ensure they don't get a buildup of heck sane, which could combust or ignite. Andi could trigger an explosion, so they have backup emergency generators, and these generators were there to supply a lot of power needed to operate things like the valves fans pumps, etcetera. Diesel generators are also used especially for cooling water systems, because many many plants have processes that require constant cooling. A nuclear power station, for example, would be enough. A good example. So the backup power source, or perhaps the backup prime mover for the pumps, is going to be again a diesel generator. So very widespread applications very widely used. And I think that's the most important thing from this lesson to realize Is that the knowledge you're gonna gain in this course you will be able to apply over and over again not just with diesel engines but for any type of internal combustion engine. So without further ado, let's get on with the next lesson. 5. Diesel and Gasoline Engine Comparison: diesel and gasoline engine comparison, I'll say for hours course spectral equals gasoline. Gasoline whose petrol depends on where you're living. So if I say gasoline or if I say petrol, then yeah, hopefully it'll make sense to you. It's the same thing. Gasoline is mostly used in the Americas, and places like that on petrol is used more in the UK and Europe. A diesel engine is similar to the gasoline engine used in most cars, both engines or internal combustion engines, meaning that they both burn the fuel air mixture within the cylinders. Both are reciprocating engines being driven by pistons moving laterally in two directions. The majority of their parts of similar, although a diesel engine gasoline engine, operate with similar components. Diesel engine when compared to a gasoline engine of equal horsepower. His heavier due to the stronger and heavier materials used to withstand the higher combustion pressures president in the diesel engine. The greater combustion pressure is the result of the higher compression ratio used by diesel engines. The compression ratio is a measure of how much the engine compresses. The gas is in the engine cylinder in a gasoline engine. The compression ratio, which controls. The compression temperature is limited by the air fuel mixture entering the cylinders. The lower ignition temperature of gasoline will cause it to ignite a compression ratio of less intento one. The average car has a 7 to 1 compression ratio in a diesel engine. Compression ratios ranging from 14 to 1 to a size 24 to 1 commonly used. The higher compression ratios are possible because only air is compressed and then the fuel is injected. This is one of the factors that allows the diesel engine to be so efficient. Another difference between a gasoline engine, a diesel engine is the manner in which the engine speed is controlled in any engine. Speed or power is a direct function of the amount of fuel burn in the cylinders. Gasoline engine to self speed limited due to the method the engine uses to control the amount of air and turn the engine. Engine speed is indirectly controlled by the butterfly valve in the car. Beretta. The butterfly valve in the corporate limits, the amount of air entering the engine in a car. Beretta. The rate of airflow dictates him out of gasoline. That will be mixed with the air, limiting the mouth they're entering. The engine limits the amount of fuel entering the engine and therefore limits the speed of the engine by limiting the amount of their entering the engine. Adding more fuel does not increase the engine speed beyond the point where the fuel burns 100% of the available oxygen in the air. Diesel engines are not self speed limiting because the air entering the engine is always the maximum amount. Therefore, engine speed is limited solely by the amount of fuel injected into the engine cylinders. Therefore, the engine always has sufficient oxygen to burn on. The engine will attend to accelerate to meet the new fuel injection rate. Because of this, a manual fuel control is not possible because thes engines in an unloaded condition can accelerate a rate of 1 2000 revs per second. Diesel engines require a speed limiter, commonly called the governor, to control the amount of fuel being injected into the engine. Unlike gasoline engine, a diesel engine did not require an admission system because in a diesel engine, the fuel is injected into the cylinder as the piston comes to the top of its compression. stroke. When fuel is injected, it vaporizes on ignites due to the heat created by the compression of the air in the cylinder. So let's go back to the top. Will do. Short recap. I like to read it all way through on Do a Recap because we can admire and comments and makes a little bit more lively than if someone just read an entire book and cause it. Of course, sorry, we all will go to the top. A diesel engine is similar to gasoline petrol engine, and my car's true. The diesel engine and the gasoline or petrol engine belonged to the internal combustion engine family there reciprocating piston engines. So we've got gasoline or petrol on one side, and we got diesel on the other. The compression ratios, though, differ quite largely. The average car with a gasoline engine has a compression ratio of only 7 to 1, whereas a diesel engine has a compression ratio ranging from 14 to 1 to 24 to 1. Compression ratios are actually quite useful for determining how efficient on engineers or our efficient and machine is. If you have high compression ratios that normally indicates that the amount of power you can extract is also quite high. So steam turbines they'll actually put the discharge of the steam out of the steam turbine on the vacuum. And that's because they get a larger pressure drop then because it's under vacuum at the outlet than if they had just they normal out, Let's say zero bar or zero p S. I. So the amount of power that we can attract would be the steams max pressure is it into the turbine and avoids Esteem Inlet pressure on, then the pressure on the outlet, which is under vacuum. So the difference between P Max and P minimum indicates how much power was extracted or how much power could be extracted. And it's the same full compression ratios. So if you've got a compression ratio off between 14 to 1 to 24 to 1, that's far higher than having a compression ratio that is around 7 to 1 on. This means we can extract more power on. This gives us a higher efficiency. That's one of the reasons why diesel engines are more efficient than petrol. Gasoline engines is because the compression ratio is higher on the power stroke in a diesel engine is also longer because the compression ratio is higher. So that's the main reason why these engines are more efficient than petrol engines. Gasoline engines. Another big difference between a gasoline and diesel engine is the manner in which we control the engine speed. Gasoline engines will regulate the amount of they're going to the combustion space. And if we regulate the mouth, there were also regulating them out of fuel. That's mixed with the air on. That's the way we regulate the power output of the engine or the speed with a diesel engine . This is not true because what we're actually going to do, we're going to allow the same volume of air into the combustion space always. But what we're gonna do is regulate the mouth fuel were injected into the combustion space , and we do this by using a fuel injector. However, if we can get mawr air or more oxygen into the combustion space, then we can add more fuel and we can get more power out off the engine. We're gonna talk about this later. On with me to talk about turbochargers and superchargers is because essentially, the more oxygen we pack into that combustion space, the more fuel we can add. And then the more fuel we burned, the more power we create. So this compressing of air and adding more oxygen is a very good way to get more power out of the engine without increasing the engine size, so we can create a lot more power. But we have to pack in more oxygen, and in order to do that, we use a supercharge or turbo charger, which we'll talk about later on in the course. There's also a comment here concerning a governor. Governors came about during the Industrial Revolution, and they were used to control the amount steam going steam engines. The concept still works today. They're very interesting item of machinery. Centrifugal governors work on centrifugal force. That means if you accelerate too much or if you're operating the machine at a very high speed, the governor will automatically slow it down to a pre define speed. If it's operating too slowly and the governor will increase, the speed of the machine is purely mechanical, but as I say, very interesting was used a lot in the industrial Revolution, and if you go to the bonus section of this course, you'll be able to watch the video, but just keep in mind. It was used mostly for steam engines. Governors nowadays are Mawr, Elektronik, their electronic Lee controlled engines. They actually call it Electronic Control Unit. You see you and that's what we're used to controller diesel engines today going next lesson . 6. Free Resources Note: again from the stress in this video that alone, watching and listening is a very good way to learn. I really do encourage you to use the free resources available in this course, such as interactive freely. Models go to them on test what you've learned. One of the most important aspects. I think before you go too far into the course to learn about is the Are the aging components you should be able to identify on. Label them without going into too much difficulty. If you can't visualize a component in your mind when on talking about it in the videos, there could be quite difficult to loan around. When I was first learned in college, there was safety from words we use different terminology on this got me really scratching my head. And this is even based things such as when they use Conrad Piston Rod interchangeably or when they say connecting Rod and Conrad. I think there are two different things. Is something okay? It might just be me to have that problem, but I see No, I encourage you to use the free resources. Click on the three D model leaks air available load of the models. Just have a look around on learn all the terminology on even stuff like talked extensive one dead sent to the board of stroke. Whatever. Learn that as well. And once you learn all that and you know the comm parents, you'll be able to cement what you've learned. Lead on rest, of course, Progressive. Anyway, check out. Enjoy the resources and if there any questions or comments, you know? 7. Major Diesel Engine Components: major diesel engine components to understand our four stroke diesel engine operates on understanding of the major components and how they work together is necessary. Used to blow three D model to learn the engine terminology terms on the main diesel inching components. Use the annotations quiz feature until you're sure you can visualize each component easily . So in this course, we've got links to a lot of three D interactive models on that should be in the bonus area of the course, or you'll find it somewhere in the course notes, depending on where you access in this course, it's a Pdf document. There are a lot of links in there. They go to Savary dot com on If you click on these links, then you'll be able to load up with three D model, much like I'm doing now. Andi, you can see if I use my left mouse bottom can spin it around here. Go up, down, etcetera. Use more right compound across Andi. If I click here, I can actually load what they call annotations. These a little moz on these little notes on the engine on Differ. Click on them. It allows me to see the name of the component. I'm over here. I'm over here. On this way, you can learn all of the names off the engine components. I would strongly advise you to do this. If you go on there, use the quiz feature that you can just click on the item here on it says Click on the Bushrod and then you go off and find the push rod wherever that may be. But the point is, is there on? If you go through and use the tools, you'll really cement everything that you're learning and consolidate it. There are over 30 separate links. A lot of them are for a diesel engine or automotive engineering. So I strongly advise you to check out. I think is really cool Tool. I actually built itself over last couple of years, and I really like it a lot off. The models are animated, which we'll see later on the course as well. Now, once you're completely comfortable with ALS, these names of the components and everything else on the terminology etcetera will turn the quiz office. I could get me wrong, then you can progress with the course on. It makes a lot more sense. It's just a lot easier to learn if you know well, the terminology beforehand. Or at least have a rough idea, so you'll learn it now once you might forget in a week. But I should progress through the course. The terms will pop up again, and then you'll say, Okay, I remember now, and it's cement Sit in your head. I think you actually supposed to when you're learning repeat stuff like a week later and then three weeks later, and then six weeks later. But as you can imagine that when If it does this, so would take the short cut through and just say, work through this into you know, the names. Take the quiz feature on afterwards. You should be completely comfortable with pretty much all the terminology and all parts, So check out hope you like it. Any questions or comments? Please do. Let me know 8. Cylinder Block: the cylinder block. The cylinder block is generally a single unit made from cast iron in a liquid cooled diesel . The block provides the structure rigid frame for the engine cylinders, water cooler and all passages and support for the crankshaft and camshaft bearings. So let's load up still in the block now. Okay, so we've got our ceiling. The block. This looks more to be of stainless steel than cast iron, but I think that's Mawr. Just a problem. I've never seen a stainless steel cylinder block. Perhaps they exist anyway. There is a cast on peace. Imagine that's Castan looks a bit more rough than this. Usually it's not so highly polished. Stuart Little spin a vassal in the block. Okay, so we can see straightaway. We've got six cylinders. 123 free. On the other side, the engine is a V type engine that's of the six in this case, in the shape of a V can see the shape there, and there's six cylinders and total. So they call that every six. We got a lesson on that coming up. We've got a compartment or a hole in the top for the camp Chef. What is this space here, and we've got a hole in the bottom for the crankshaft. The crankshaft connects to a flywheel which would be housed in this area here. And then we connect our load either to the flywheel or perhaps, too they send here. We've also got some connections on the side. You'll see a lot of these round holes, such as here, here, here, in here. These round holes are for attaching appendages. Sometimes this might be a starter motor, or perhaps just cables, temperature sensors, oil coolers, just random bits and bobs that you need to operate the engine, these brackets that you can see one and two is too, on the other side as well. Therefore attaching the engine to whatever it's gonna be attached to this might be some sort of bed plate, perhaps in a large truck, or perhaps in a ship, because sometimes you have an engine like this with a very long shaft outside here on the now the propeller on the end of it. So these four brackets are for securing the engine to the bed player, or at least to whatever it's gonna be attached to on the sill in the bloc is essentially a house where you can attach everything without a cylinder block you would never base on which you could build on the ceiling. The block gives us that base. It allows us to put in the cylinder sleeves. It allows us two hours to fly wheel to attach the alternator to attach the starter motor on and stuff like that. It's also got a little cooling water passages you'll sometimes hear cooling water referred to his jacket water. It's the same thing, so we used the cooler war passages to take away. Heat out the engine, stop it overheating. We've got lubrication or passages on. These are used to lubricate the various parts of the engine, as well as to take away heat on. All of that's happening in the cylinder block, so it's an important piece of the engine. Without it, the engine would not be able to exist. It prevents your engine overheating and gives us a base upon which to attach everything else. So that is the cylinder block 9. Crankcase and Oil Pan: crankcase and oil pad. The crankcase is usually located on the bottom of the cylinder block. The crankcase is defined as the area around the crankshaft crankshaft bearings. This area encloses the rotating crankshaft and crank whips on direct returning oil into the all pan. The oil pan shown below is located at the bottom of the crankcase. Your bank collects and stores the engine supply of lubricating oil. Large diesel engines may have the or pan divide into several separate pans, so we've got an oil pan. Sometimes you might also refer to the old pan as an oil reservoir or an oil sump. Load up the model. This model is not very detailed. Is actually missing a couple of pieces, one of them being the holes where you'd attach the oil pan to the engine. But the rest is relatively accurate. Let's have a look again. Got a stainless steel one here rather than a cast on one. But let's ignore that for a moment. It's straight in the or pan out from the top. Usually, there be holes here, all the way around the oil pan. That is how you would attach the all pan to the engine or zoom out so we can see that so low. The holes around here on around here, it's just zoom in can have a look at the shape of the open. He's got quite an interest in shape, comes down here, drops down into the main oil reservoir or some section. It's quite shallow at the top on the left side, on very deep. On the right hand side, we've got two holes. The one hole might be for an all return on the lower hole is more likely to be for an oil pickup line. In other words, where would extract your from the oil pan? Actually, usually call this in all some, but I think it's more in America you call an oil pan. Anyway, that's been around, so we've got an oil return line on. Then we've got a outlet or your pick up line from here. Sometimes you'll actually see on an oil pipe coming into the sump on it. We'll have a little filter on it, and that's where you're suck up the all out of the sump or other pan, I should say on we can see. Also, we've got a hole in the bottom. The hole in the bottom is for draining the oil out of the oil pan, so we cannot do that. We can drain the oil out. We want to do this periodically. This will be based upon the number of hours, or perhaps how far the automobile has traveled, or perhaps situation in time. So, for example, we might say we need to change the oil every 6000 service hours or 5000 service hours, whatever, so that might be applicable for a diesel generator. But we might also say we need to change your every 10,000 kilometers or whatever on that might be applicable for a car or for a van. Well, we might just say the all has to be changed it no later than every 12 months. And this is for a diesel generator to the only works, for example, 12 hours a year, so as very low service hours. So in order to ensure the all condition is OK, they will typically say gay, you need to change the oil after 5000 hours or 12 months. So that's normally how you would decide off when and how to change the oil that soon our second can see from the shape here we would actually sometimes have. In fact, most of times I would say compartments built into the or sump, so there'd be a line going down here on a line. Going across here on it would be split into sections. The reason we split the oil some into sections is because when the ship moves or when the water mobile moves or whatever the diesel engine is attached to, the oil was slop around. It will run from one side to the other and this creating imbalance. We actually call this the free surface effect. It's a massive topic on ships because the last thing you want is a lot of all sloshing around on a boat or, for example, a lot of water. Because imagine, a big wave comes over the side of the ship. If that water is not discharged as quickly as possible, or if you don't get rid of the water as quickly as possible, it's gonna move back from one side and shipped to the other left and right, left and right, and it's going to cause the ship to roll on. They call this the free surface effect is actually a pendulum effect, and it can get worse and eventually causes the ship to turn over. In fact, in a lot of instances in the past, they have these ships called Roll on Roll Off. And that's where they dropped the front of the nose down on the ship on if a big wave comes in when they dropped the nose down because normally the cars just drive off. It is a set up the ferry, but if they dropped the nose down on a big wave comes in. The wave spreads out all across the length of the ship everywhere where the cars are parked basically, and then the ship rolls a little bit on all of that water rolls to one side on the ship. Tips over on This has happened quite a lot in the past, and that's why the free surface effect is quite a big topic in the ship industry. However, we're not talking about a ship here is such. But even with a little oil sump, this one here, the old slopping around does cause an imbalance on this imbalance is no desired. The other interesting aspect about this, son is that you would normally have either a dry oil sump or a wet oil sump. This is a wet oil sump because we store the oil directly underneath the Engy. So underneath the engine is where we store our oil. A dry something. You don't do that. You extract the oil immediately from underneath the engine and you store it at a remote location, so this might be a separate tank, but you're pumped the all back to the engine in order that you can lubricate the engine and use it in your normal system and service. The reason we extract the oil immediately from the engine is because in fact, there are several reasons one of them might be that we wanna have a lower center of gravity and we want a mountain. The engine lower down. So we don't want this huge lumps sticking out the bottom of the engine. We want a shallow panel the way long like this, and this allows us to lower the engine down this much further. So imagine the open ended here. Well, we could cut off the entire bottom. We're extracting all for a whole here instead of down the bottom on. Then we can move the entire engine along the way down to this point here, and then we've got a lower center of gravity, which gives us better balance. So that's one reason why you might wanna dry or sump instead of a wet one like this one. But the other reason is for safety. Sometimes you want a dry or some because you don't want to store a large volume of oil directly underneath the engine. Remember, if there's any hot gases elite past the piston, or perhaps there are bearings, it get very hot. If the bearings are not lubricated properly, they get very hot. They create an all missed on this. All missed ignites relatively easily. This what they refer to is a crankcase explosion. This is not such a big topic on smaller engines, but it is a big topic on larger engines. And in the past, people have died because a bearing got hot in the engine or on the main crankshaft on the hot bearing actually not only heated up oil and turned its oil vapour oil missed. It also acted as the ignition point eventually got so hot that ignited the oil mist on there was an explosion. So again, for medium and very large engines, it's quite a big topic. And that's one reason why you might say, OK, we don't want all this oil sitting on the engine will extract it to a remote location On that way, if there's ever a source of ignition, or if there's an explosion, we won't be adding fuel to the fire. So that's another reason why you'd ever dry or some instead of a wet one. Let's have a look around now, see if we missed anything I conceive one other important aspect here that might be of interest can see on the lower side. We've got a very strange shape to his weekly shape. Whenever you see a weekly shaped like this, you should say to yourself straight away, Okay, that is for exchanging heat. Almost every time you see a squiggly shapes such as this one here, it's gonna be there because you want to increase the cross sectional area off the material , or, in this case of our lower side of the oil pan and you want to increase a cross sectional area in order that you can transfer MAWR heat to the ambient air or whatever is surrounding the piece of metal or whatever is surrounding the squeegee shape. So in our case, we've gone all something's got this squiggly shape. So it's telling me. Okay, they wanted to increase the cross sectional area of the or sump in order that they could transfer mawr heat to ambient air. So there's probably gonna be an air space underneath here. There's not gonna be water or oil or anything like that. It's just gonna be sitting with their around it on what we're trying to do. We are trying to get rid of the heat from the oil and pass it on to the air. If we can cool the old down, then we can recirculate back into the engine and it's going to absorb more heat and then we'll call it back down again. Remember, the all is there not just to lubricate its there to lubricate Andi. Cool. A lot of people forget this. They just think oil is for lubrication. It's no, it's for lubrication and cooling. And in order for the cooling part of yours work, we have to learn its temperature before it goes back to the engine on. This is one way we're going to do it. We're gonna pass air over the underside of the or sump. It's going to take away the heat from the oil because he always gonna pass the heat to the all some casing and then the air is going to take away that he from the some casing itself on this is ultimately going to cool our all down and will then use it for cooling the engine down on the process continues. So I would be guessing that if this was married in a truck, for example, the air is going to come from the left side of screen. It's gonna blow across you all sump. Take away some of that heat, Andi. Then the process going to continue. The faster the engine rotates, the more power that we're going to transfer to the wheels on, the faster the automobile will move. And that means we're gonna passive mawr air over the or some. So this is quiet, cool or quite interesting, because as the air passes over, we're gonna get more and more air as the engine accelerates. Normally, as a rule, because as the engine goes faster, we're going to try and use that to accelerate or two traveler higher velocity. So as we're traveling at a high velocity, we're going to come into contact with more more air, and that is gonna be blown across that all something on. We're gonna call down the all. So it's a very good relationship, and you actually see it is quite a lot with engines. You'll have a lot of situations where the engine speed increases on the pumps will increase with it. So you have a very proportional response to things such as cooling, which is useful because you need to cool down the engine proportionally to the mouth he's generating, and we'll look at that in our cooling water video later on in the course. So that is, uh, oil sump. Sometimes you'll also see a dipstick mounted onto the side. In fact, quite often will be a hole drilled round about here, or perhaps on the other side about here, and I'll allow you to dip the engine. Oil on Checketts level typically engine or is quite black. You can test the quality, the engine or your fingers. Just rub your fingers are dealing. Wear a pair of gloves, but rather on the oil dip. Stick on. You can feel then, if you always got any sandy particles in it. When you changed your the older be quite clean it return to an amber kind of color, at least for about a day, and afterwards you will go quite black again. But things to worry about arm, or if you can see sandy particles or fill them in the oil and if not generally the or should be okay. The old does have to be changed, though irrespective of if there are particles in the oil because the properties allow it to call, the lubricate will wear out over time, and that is the reason you change the oil. One other important factor as well is that when you change your you should try and do when the engine is warm, because you're then is quite running, and it's a lot easier to extract the oil from the engine on. Also, they all will drain down from the engine over time so that when you do the all change, if the orders quite warm, it's all drained down on you. can get most of the all out of the engine. If you drain your when the engine is cold, then you're not gonna get all of that oil out because he comes quite thick. And that means that when you refill the engine with new oil, you're actually just mixing the old oil with the new oil or parts of the old war with the new oil. So give that mind if you ever there in all change, try and do with engines Quite warm. Allow the oil time to drain down. But don't wait until the all is totally cold. Okay, sir, about that. Seem to go up court and distracted. They're talking about many different aspects of the engine, but we should have focused solely on the oil pan or sample reservoir. Anyway, you found that. Listen interesting, Andi. I think we can move on now. 10. Cylinder Sleeve Or Bore: cylinder sleeve or bore diesel engine Jews, one of two types of cylinders in one type, each cylinder is simply machine or board into the broadcasting, making the block and cylinders and integral part in the second type, a machine still sleeve is pressed into the block, casting to form the cylinder with either method. The cylinders, sleeve or board provides the engine with the cylindrical structure needed to confine the combustion gases and to act as a guide for the engines. Pistons in engines using sleeves. There are two types of sleeves wet and dry. A dry sleeve is surrounded by the middle of the block and does not come into direct contact with the engine's coolant water. A wet sleeve comes into direct contact with the engine's coolant water. The image below shows an example of a white sleeve. The volume, enclosed by the sleeve or bore, is called the combustion chamber, and it's the space where the fuel is burned in either type of cylinder sleeved or board. The diamonds of the cylinder is called the bore of the engine on his stated in inches, which is imperial or millimeters, which is metric, for example, the bore of the 350 cubic inch Chevrolet gasoline engine is four inches, so we'll do a quick recap, the cylinders sleeve or the bore. There are two different types. You can either have cylinder sleeves that are a part of the cylinder block. You're literally just drill into the cylinder block and that will be your cylinders sleeve . Or you can have the type of sleeve that you insert into the cylinder block were into the broadcasting, and that will be then your cylinder. Lina. So we have two types. We have a dry type ceiling to sleeve, and this is a type that doesn't come into contact with the engine's cooling water system. And we have the wet type cylinders sleeve on. This type does come into contact with the engine's cooling water system. It's now load up. The model on will be able to see in this model where the cooler war passages are as well as where the air goes into the combustion chamber on the top of the cylinder liner itself. The model is one of the new ones, so it's got a bit more detail on personal. Find it a lot better than some of the previous ones. So here is our cylinder, Lina concedes, got quite a unique shape. It gets gradually narrower as it comes down. We've got holes. In fact, let's just do a complete spin first before we get into details. There you go. You can see it. That's how it would usually look from the outside. Andi, that's how it looks when we have a cross section. So we cut a piece out here. You've got these holes in C one over here on another one here, etcetera. So the cylinder line will slide into a cell in the block on these holes are going to connect to the jacket, water system or cooling water system on its gonna enter into the cylinders sleeve through these holes, or the cooling water will enter through these holes. The air is gonna enter through these ports. You can see there rectangular in shape to do another spin. Consider the air we just rushed in through the ports on. Then it's in the combustion space and a pistol would be down the bottom on that would travel upwards on, compress the air and then close off these air inlet ports. All right, I'll just seem to decide now. Okay, so we've got airports. We've got a jacket. Water inlet holes. Once the jacket water is in the cylinders sleeve, it's gonna flow upwards. So it's going to surround the entire cylinder sleeve. We can see the could a war passage here that we can go in so you can see there's a passage all around the cylinder. Lina, we're going to absorb the heat. And again, you can see again. There is the passage all the way up. The still in the liner when it comes out off the top can see we've got all the holes on the top where the cooler water would flow out. It's gonna have absorbed some of the heat from the combustion space because that heat was transferred through the cylinder liner to the jacket water so the cooling water or the jacket water is absorbed. The heat and it is exited out the top and entered at the base flow would be in here, huh? Aunt, out of the top on. Perhaps it picked up or increased in temperature about 10 degrees or more as it passed through this cylinder line a passage. So that's why I cooling water system is doing. It's taking away some of the heat from the cylinder liner on this stops the cylinder liner , then expanding too much due to the thermal temperature. If we have a very hot cylinder, liner is gonna expand more than one that is a called a temperature. But more importantly, it stops the cylinder line a temperature increasing to a point where we would perhaps get thermal damage to the liner or maybe would even melt. So that's why we want to take the heat away. If you get a situation where there's no cooling water and no lubrication or etcetera, then the engine will simply sees. It just won't rotate anymore. The parts will press together because they become very hot on engine will stop rotating. So that's why I want to get rid of the heat, and that is our wet cylinders sleeve 11. Straight and V Line: Straight and V Line. Most diesel engines are multi cylinder engines and typically have their cylinders arranged in one of two ways and in line or a V, although other combinations exist in an in line engine, as the name indicates, all the cylinders air in a row in a V type engine. Cylinders are arranged in two rows of cylinders, say, an angle to each other, but a line to a common crankshaft. Each group of cylinders making up one side of the V is referred to as a bank of cylinders. Take one. If you see or hear the term, it's a or it's a V 12 V simply refers to the cylinder arrangement. Yea or the 12 refers to the number of cylinders. That's the total number of cylinders. No, the total number on each bank tip, too. If you see or hear the term, it's a straight six or it's a straight eight. Straight simply refers to the cylinder arrangement. The six or eight refers to the total number of cylinders so we can see here that we've got 123123 So there are six pistons there in a V shape, so we have a V six engine, we can actually load that engine up and we will do later on the course. That may be a load up in a minute. We can have a look at it. Well, we're talking about here is straight and the line. So in, say, straight. Six. It's a engine with Pistons. Aaron a line on. They have six cylinders. They say it's a V eight. It's an engine as a V configuration, but there are eight pistons. Let's light this up. We can never look at the sixties or engine or the six internal combustion engine on will actually be able to see working as well. This model is available in the links that I've put in the P. D. F. I let me just soon out slightly, we can see the engine operating. We can increase the speed here. We can decrease the speed over here. Okay, this is a nice, slow speed on then It's fully interactive, so you can have a look at it. Check that the vowels wrote me when they should be took us a while to configure this correctly. And then you'll see the pistons moving up and down, etcetera. But coming to a point. We have a common crankshaft. This one here, in fact. So we have a common camshaft. This this item in the middle here on the crankshaft is the lover Shaft going along here and we can see the camshaft is rotating along with all of our pistons. There are six pistons and these pistons. Aaron, this shape off the configuration. So that means we got a V six engine, and that's it. So that's what in line on the type engines are. 12. Piston and Piston Rings: piston and piston rings. The piston transforms the energy of the expanding gases into mechanical energy. The pistol moves linearly within the cylinder Lina Pistons, a commonly made of aluminium or cast a line allies to prevent a combustion gases from bypassing the piston on to keep friction to a minimum. Each piston has several metal rings around it, and these rings a referred to as piston rings so you can see our piston that piston rings are actually at the top here, near the top of the piston head. But what we'll do with low that model in a moment, the piston rings function is the seal between the piston on the sill in the wall. Pista rings also act to reduce friction by minimizing the contact area between the piston and cylinder wall. The rings are usually made of cast iron and coated with chrome or militant. Um, most diesel engine pistons have several rings, usually between 2 to 5, with each ring performing a distinct function. The top rings or ring act primarily is the pressure seal. The intermediate ring or rings act as a white bring to remove and control the amount of oil film on the ceiling, the walls, the bottom rings or ring is an oil ring and ensures a supply of lubricating. All is evenly deposited on the ceiling. The walls to generally a small to strike engine will have to piston rings on a four stroke engine. Three. It's possible for one ring to have multiple roles. For example, could be a wiper andan oiler. So piston rings they're used to seal the combustion space. Now, remember, in an engine we've got the cylinder head. That's gonna be the top off the combustion space on on the side. We've got the cylinder liner, so that forms the sides of the combustion space. But in the bottom, there's no seal. The piston does make off the big part of the seal on the bottom, but it doesn't make up the whole part of the seal because you've got to imagine that if you haven't got to imagine, I'll show you in a moment between the Let me just pause this for a moment between the piston and cylinder Lina, there's gonna be a small amount of space now we don't want have piston running right next to decides off the liner. What we actually want to have a piston rings and these almost come into contact with the cylinder liner. Now, the piston rings aren't showing here, so I'm gonna load up another model in a moment. But these are actually called piston ring grooves in C one year. Andi, another one here where the mouse is another one here and another one here. So that's where the piston rings would sit on its The piston rings that form seal between the cylinder liner and the piston. Now, I said, here they form the steel. That's not 100% correct because we're actually going to use lubrication oil to form the seal. Were not gonna press the pistol rings against the cylinder, Lina. We're gonna press them very, very close to the cylinder lineup, but they're not going to come into contact with cylinder Lina. So the bit that's gonna actually do the ceiling Lisa lubrication oil, which is smeared as a light film between the cylinder Lina on the piston rings. So that's what gives us our seal on the piston rings press almost out to the liner, but no, all the way. We can actually see, though we've got here Since we've loaded up this model, we could talk about it a little bit, got a piston crown on. Then we've got the place where the piston rings would attach. So these are our piston grooves on between the Piston Gru's We call these landings And then we would have piston rings which stick out each one of the groups on We've got our entire piston. I got a 10 and this would slide in and connect our Conrad Teoh Piston, which, if you did go through and learn all the names, that should all make sense. The comrade is this piece here. Some people say Piston rod. Some people say, Comrade, some people say connecting rod. There is a difference during the piston rod and a connecting rod. The connecting rod of the comrade is the one that you're likely to see. The piston rod is the one that you're going to see only on very large to stroke marine vessels or marine ships. So you can call that the comrade. Although a lot of people used the terms interchangeably, they'll say, pissed abroad instead of comrade. But comrade connecting Rod, that is this piece here you can see we got bearing on the bottom white metal bearing or plain metal bearing. We're going to talk about that later on in the course. Got totally separate lesson for that and we can see Let me just explode outwards. Those all our parts on def, we take cross section. We can also see some channels here for lubrication can actually assemble it and then you'll see how it looks. But let's see if we can just quickly load up model concerning piston rings. In fact, we don't need to load up a model of just noticed the piston rings and now they're So when we exploded it out, they must have been missing on. Now you can see them. There are the top. I'll put a cross section back so we can see the full piston ring. So these air a piston rings. We got 123 and four. The bottom one is most likely a spacer with a scraper that is for controlling amount of oil that is left on the cylinder line of war or between the piston rings and the liner. Don't want too much or too little, or you want the right amount on it see oil scraper, all the wiper that's gonna get off any excess oil. We've got the ones at the top. The top two most likely gonna be our compression rings on their slightly stronger and thicker than the other rings because they have to withstand the pressures that air created within the combustion chamber. Let's just assemble the piston rings for a moment. Okay, so there you go. You see, now the piston rings, they are now installed onto the piston itself. And you can see we got 123 black on one on the bottom. So the gist of rings are firstly sealing the combustion chamber on That prevents the exhaust gases or the air and fuel mixture from passing by the piston rings and getting into our crankcase. But they're also lubricating or allowing all to leak out from here. The lower piston ring Andi always gonna leak out, and it's going to create a light lubrication oil film on this light lubrication or film between cylinder liner and the piston rings is what gives us our seal on. Also prevents the cylinder liner and the piston rings come into contact with each other. Remember the oil is there not just to lubricate it, also there to cool. But in this instance, the lubrication property of the or is very, very important. If we don't lubricate the space between the piston rings, noticed they come out slightly further than the piston itself. But if we don't lubricate the space between the piston ring and cylinder Lina, then we're going to get micro welding on. The micro world is going to damage our piston rings, and that ultimately might lead to the piston rings, not sealing correctly. And we're gonna get what's called blow by. That means exhaust gases. When we got to discharge the exhaust gases on the upward stroke to talk about after the exhaust gas is going to just pass through here, whatever is in the combustion space is just gonna leak. Passed on, go into a crankcase. So that's not we want. Remember the combustion spaces totally sealed or is supposed to be totally sealed on. We don't want air or fuel or exhaust gas just leaking into our crankcase, so that's the reason why we have the piston rings in the first place. And that's the reason why it's important the lubrication or he's in a good condition and is able to create this very thin oil film seal between the piston ring on the sill in the liner. So that's what piston rings are doing occasion. You have to change them. I have changed him quite often when I worked on marine vessels. Piston rings a huge, literally bigger than a meter in diameter. You have to change them every now and again. You do get blow by Andi, you get gas is going into the crankcase and you don't want this because these could be potentially very hot gases on hot gas. Mixed with oil is not great. So you don't want those going into the crankcase, which is full of oil balm, dry aggressing here. So that's essentially a piston rings look when they're installed. You now know what they are doing and why we have different piston rings on a piston on if you ever taken engine apart. One of the things that you may do a typical man and stop is to change the piston rings wherever possible. They make it easy to or relatively easy, should I say, to make wearable parts easy to exchange now wearable parts are things like pista rings. Andi. Changing piston rings is, once you get to them quite easy. But there are over wearable parts on the engine, and you also need to be able to access them and change them easily as well. There's no point having your part on an engine that typically wears away over time on, then finding out that you can't replace it or you can't renew it or you have no access to it. So any wearable parts are gonna be relatively easy to access and change on. The same goes for filters as well. The lubrication filter the fuel, filter, the air filter. Or there may be more filters, maybe air filters, lubrication filters, etcetera. They're always gonna be mounted, an area that's quite easy to get to where they should be on. They're gonna usually employ something such as a screw Fred or some sort of snapped fitting . In order, you can exchange filters easily and quickly. It's a poor design. If you have filters, you have to change every month, and it's a real nightmare to change the filters. So I come back to my point. No, this lesson is about piston rings and not filters. The piston rings are there. You can see them installed, you know. Know what they do. And you'll also know that when you service the engine, they're gonna be potential an item that you might need to change. 13. Four and Two Stroke Lubrication Oil Systems: I I just wanted to put a brief video into the course at this stage because I got a question recently from a student and they were asking me about piston rings and lubrication on. One of the questions that was asked was, What's the difference then, between two straight lubrication on four stroke lubrication? And it was good question. Admittedly, I missed out. So this shows the importance off getting a bit of feedback, sometimes from students, because I'm not perfect, Andi. Sometimes I just forget to explain stuff a bit more clearly. So the difference between two stroke unforced ratification could be either very little or quite a lot. If you're looking at a very large two stroke engine, it will have its own separate lubrication system, and it will have its own pumps and filters. Etcetera on will use that litigation or system for regard ball lubricating the space between piston rings on the line. However, when you have small or medium sized engines, such a small medium, four stroke engines, then they will also have their own lubrication system and lubrication pump etcetera. But that's for small medium four stroke engines, where you could say small medium and large, small to strike engines on very lives to strike. Engines are different. The very large two stroke engines has mentioned previously have their own lubrication or system. The small to strike engines do not have a dedicated lubrication all system. There's a reason for this. We want to keep our high power to weight ratio, even though the engine is not very efficient. Now, if we start installing pumps and hoses and strangers on annoy oil, some foreign or reservoir, then we're gonna have a bit of an issue, because all of a sudden are low weight. High power engine does not have this high power to weight ratio that we had before. So in order to get around this, what we do is we mix in lubrication oil with fuel. Now, when we do this, we mix it in the fuel tank, for example, and it might be one past 2 50 or to pass to 50 or whatever on the oil that has been mixed in with the fuel will then lubricate the cylinder Lina or the space between the cylinder line and the piston rings. Unfortunately, this is not an exact science, as we draw in the fuel and the lubrication, or it's gonna generally leave a film all over anything that it comes into contact with. So it's gonna be a lot of engine parts, such as a crankshaft that's a Conroy piston piston rings, etcetera. The problem is, this oil film is not gonna be evenly applied because it strongly depends upon how the flow path through the engine is regulated. Now, if you're feeding Aaron from only certain sides or certain directions, then you go yet Mawr oil spread over that slow path, then perhaps a bit to the side where the flight path is no so strong. Now. This is another problem with to strike engines. The lubrication or film between the piston rings and liner is not universal. It's not evenly spread on. We usually end up having to change A piston rings a lot more often for two stroke engines than you would for a four stroke engine. So that is another problem with a two stroke engine is another reason why they have not found widespread application as medium sized engines. Also, that one reason it's not all of the reasons, however, for very large to strike engines and I'm talking here with a piston. Weighs one piston. Wait five or six tons. They having a few extra pumps on the side on a lubrication oil tank is not such a big deal . But that is only ever really seen are very large merchant navy vessels. As soon as you get off a large ship, any type two stroke engine is going to see that is used for widespread application is gonna be quite small one. So long, mother. Leave, brother. Whatever. Anyway, I hope that clears up a little bit. If not, shoot me a message and I will recount this video and try again. 14. Connecting Rod: connecting rod. The connecting rod connects the piston to the crankshaft. The rods are made from drop forged heat treated steel to provide the required strength. Each end of the road is bored, with smaller top board connecting to the piston pin, also known as a risk pin in the piston. The large four end of the road is split in half and bolted to allow the road to be attached to the crankshaft. Some diesel engine connecting rod to drill down the center to allow all travel up from the crankshaft and into the piston pin and piston for lubrication. That's what we've got here on our diagram. We've got a Conrad Oil actually comes in through the crankshaft into through these holes at the bottom and then travels upwards. So that's a board or passage on. It will lubricate pin, where every spin on also some oil will enter the piston. On this all will take away some of the heat, which has been generated during combustion on. Doyle will also be used to lubricate the space between the piston rings on the cylinder liner. They all will actually leak out at this level here, where the oil wipers. So let's see or passages within the connecting rod, as I've said people refer to also has the con rod on, sometimes a piston rod. Although the piston rod is no actually a correct term to use, let's go down for a moment. We can load the model in a minute. Variation found in V type engines that affects the connecting rods is to position the cylinders in the left and right banks directly opposite each other instead of staggered, which is the most common configuration. This arrangement requires that the connecting rods of two opposing cylinders share the same main journal, bearing on the crankshaft. To allow this configuration, one of the connecting rods must be split Will Fox around the other tip. One connecting rod is also referred to as a comrade. Too many people often refer to the piston rod and connecting rod as if they're the same thing. But this is not true. A piston rod is a separate piece. It's connected to a cross said. Where is the connecting broad connects directly to the crankshaft piston rods still found in large marine engines, but not within modern automobile engines. So I wanted to have already covered. I think at this stage we can load the model. This variation found in V type engines. What they talked about there is mounting two comrades onto the same piece off the crankshaft, and they will share a journal bearing when we say journal bearing were referring to bearings there are mounted onto the crankshaft journal is actually the area where the bearing is mounted. Let's just lows this model up when we can have a look again at some of the main parts on your passages associate with the Conrad. Okay, so there we go. We got a wrist spin that is decides him here. That's gonna slide inwards when it slides in. Then we've effectively connected. Are Conrad to the piston? Noticed that we just had to back off slightly this peace here. It's the locking pin on that is going to keep responding position within the piston. Remember, we don't wanna recipients or just sliding out, so that's what we're gonna do. We gonna have one on this end, and I have one on the the other end which has been attached already. We've got Mr Rings at the top. We spoke about earlier. Go down. You see the comrade cocoa an interesting shape. That's where it connects to the crankshaft. Crankshaft will go through this piece here in order to mount it onto the crankshaft. Because the crank shaft is not straight. We're gonna have the comrade in two separate pieces. So let me just expand outwards again. Consider two pieces. We got the upper half and we've got the lower half on. These two pieces will clamp together, and we actually have white metal bearings. He's of white metal bearings here. Got the upper shell on the lower shell. Andi, these white metal bearings are going to separate the crankshaft in the Conrad there actually lubricated on one side one going to details has got a lesson about this, Andi. It prevents the crank chef coming into contact with the comrade, but allows the comrade to rotate around the crankshaft without generating too much heat. Because obviously we've got a thin film of oil. So it's only the bearing that comes into contact with the crankshaft, But it doesn't actually press against the crankshaft because the oil separates the bearing from the crank shaft. So if we go or just assemble again, we can see. We've got some oil ports here. These boil ports from the crankshaft and what we're gonna do, we gonna lubricate the space between the bearing and the crankshaft on. If I expand the model out, you can also see there's an oil passage here. Let's try and straighten up a little bit. I appreciate it's a bit confusing, Catherine. That's a bit, but you should see so exceeded piston or the comrade going off in the distance at the top of the screen, going up to the top of the piston. Andi. Then we can see we got this oil passage on drilled through the Conrad. We had baffled there, but if you go through, you can see there's a oil passage within the comrade. I will take a cross section and then we can zoom out and take a look of that. So there's our board or passage, and that passes all the way up to the top of the piston. So all the way through the comrade. That's why we get the all up to the top into the piston. And that is Ah, comrade. The comrade itself has to be quite strong. The material has to withstand all of the pressures generated within the combustion space, and these pressures could be quite large. So you need to have a material that is relatively strong. So if you have a look from the side here, you can see a comrade is quite thin. All of the power generated, though, goes through the Conrad, so it needs to be strong enough to withstand all of that pressure. It also needs to be strong enough to withstand the temperature variation, which might be quite large at the top compared to the bottom. One of the other important aspects is that if you were to chip the con rod, or perhaps it would have a dent in it on this would progress into a crack. You want to make sure that you're not gonna get a huge amount of crack propagation. This is essentially crack growth, so they've got to be strong. But I've also got a fracture if they should get a little den or a very my new crack or chip , because you don't want this piece rotating at 10,000 rpm or whatever. Spirits rotating out on that crack is going to slowly propagate or slowly grow through the comrade and then crack. However, I got to say in many, many machines that I've seen when I've visited industrial plants, particularly those with high pressure presses, it's very difficult at the Conrad cracks and fails. Now a lot of time. This is not something you can do too much about because the pressures that the Conrad is operating at very, very high, perhaps in excess of 1000 bar is being transferred through the Conrad on def. That cycle is repeating day in, day out for 10 years. Then at some point the convoyed becomes quite weak and it will crack on. Then you'll replace the Conrad. As I say. This is typically for very high pressure machines, where they use oil presses or piston presses in orders to squeeze a material together and extract the liquid. They actually used high pressure piston pumps in the gas industry because they compress the gas and pump it into the earth, and these machines is truly colossal. We're talking about getting out of hundreds of thousands of cubic meters of gas per hour, so they also compress a lot to get the gas into the earth before it's extracted again. But you can also see them in places like oil. See plants while they're squeezed together the remnants of oil, which is sometimes referred to his cake on. When they squeeze these seats together, they're going to essentially extract the oil because the liquid drips out. And that is another high pressure application for a pissed, um, press. So pistons and converts they're not just used with diesel engines. You're going to see them on piston presses, piston pumps. That design is very similar, so there's a wide range of applications on. Once you know this design, the piston rings a piston head, the piston crown, the landings, grooves that skirt, etcetera. Then you're gonna be able to apply that knowledge to many, many other items. As I've said, piston presses and piston pumps are some of the typical applications. Although you got a diesel engine, petrol engine, four stroke, two stroke engines as well, so important to learn this terminology in the components because it comes in really, really handy in many, many other industries, and for many other applications 15. Crankshaft: grant theft. The crankshaft transforms Illini emotion of the pistons into a rotational motion that is transmitted to the load. Crank shafts are made of forged steel. The fourth crankshaft is machine to produce. The crankshaft bearing and connecting rod bearing surfaces, the rod bearings or eccentric or offset from the center of the crankshaft has indicated. Below this offset converts a reciprocating up and down motion of the piston into the rotary motion. Off the crankshaft, demand offset determines a stroke of the engine. So here we've got a crankshaft. We can see the crankshaft is not a straight piece. It's actually the axis of rotation. Or here along this center line, however you can see we've got the shape is actually more like this. Comes in from the left, goes up to the right, down, right down, right up and then across here, and that is the shape of the crank shaft. When we're talking about the movement of the crankshaft rotating, we mean that this entire piece rotates, but the pistons themselves move up and down linearly, so they're moving up and down the pistons. But the crankshaft is turning that linear motion into rotor emotion or angular motion as they sometimes call it. We can see we've got these spaces here. One, 23456 seven. These are journals. That's where we would mount the bearings. We've got Conrad Bearings, which attach here, here, here, on here. And we've got the crankshaft main bearings. Which are these ones here, Here, on here. These are not the bearings, these of the journals, which is where the bearings would sit. We can see also that the top point off the crankshaft transit. In other words, when the crankshaft bearing here comes up to the top, that represents top Dead Centre, or what we refer to stop that center is when the piston travels all the way upwards on when it rotates and comes down to the bottom, such as what we're seeing here. That's what we refer to his bottom dead center when the piston reaches the bottom of its transit or the lowest point of its movement. Well, I don't this model in the moment and we can discuss that it further. The crankshaft does not right directly on the cast iron block crankshaft supports, but rides on special bearing material. The connecting rods also bearings inserted between the crankshaft and connecting roads. The barrel material is a soft alloy of metals that provides a replaceable wear surface on prevents. Calling between two similar metals, I e. Between the crankshaft and connecting rod. Each bearing is splitting toe half's to allow assembly of the engine. The crank shaft is drilled with all passages that allow the engine to feed oil to each of the crankshaft bearings and connection rod bearings on up into the connecting rod itself. So we can see you've got a plane, metal bearing white metal bear in plain metal berry and thin film bearing. You'll hear it. Other lives for names, sometimes Babbitt metal bearing. We got into a video on that, so I'm not gonna discuss it too much right now. The crankshaft has large weights, cool counterweights, the balance, the way of the connecting rods. The's waits, ensure and even forced during the rotation of the moving parts Tip one crankshaft Counterweight, also referred to as the crank webs T two bearing split into two parts is known as a plane bearing. I should actually say here that the bearing itself does not have to be split into two parts . Always a plane bearing is a bearing as a very large cross sectional area. Andi, it could be as one single piece. However, for diesel engines or for combustion engines, you're not going to see a plane bearing that's in one single piece. You're going to see a plane bearing that is in two pieces, or perhaps four, depending on the size of the engine. So a plane bearing can be in one piece. It might not be spent two parts, but when you're gonna see on combustion, engines will be split in two parts. Tip. Three soft metal bearings have a shiny white gray appearance and sometimes referred to his white metal bearings or bad it bearings. Babbitt was the inventor of the soft alloy, so I want metal bearings quite soft. And you, Mr Babbitt, was the inventor off this special metal alloy. Like I say, they were gonna discuss that in one of the next videos. When we talk about plain bearings so it only Teoh die aggress onto that at the moment, let's load up the crankshaft. Crankshaft itself is quite an interesting piece or an interesting part off. The engine has a very unique shape on. It's also responsible for delivering the lubrication or to the Conrad on a lot of time. You'll also see that the all it sprays out off the crankshaft on lubricates some of the internal components. Let's have a little we can see that. Let's just do a spin. So there's our grand chef from one angle on the other. We've got a crank whips. It's these counterweight pieces here. Yeah, and we can also see them here on here. I'm here. They're so there's our crank webs or counterweights. On the end of the crank Web, we're going to have a Conrad bearing or a journal. It's this piece here on that connects to our Conrad or a connecting rod. You can see we've got holes for lubrication. It's these two old here. That's where lubrication all is delivered to the Conrad bearing on through the Conrad. The actual lubrication will come in through a hole, perhaps here or the other end. It depends, so we'll deliver lubrication or and will pump that around the engine to the comrade through the crankshaft on. Sometimes it will spray out the crankshaft itself on lubricate those internal components, so I notice you. We've got a crankshaft that is offset the centre axes of rotation through here, but he's fine. But when the crankshaft rotates and you can see here is Ah, comrade journal. When that rotates comes up to the top, the piston will be pushed up as faras. It's going to go in the engine up to what they called top dead center on. When it rotates around the other way, we're going to go away, back down, pull the piston downwards on. We're going to reach a position that they call bottom dead center. So that's why I crankshaft is doing. We're transferring that linear motion to Rosary Motion and Ross able to get lubrication to the various parts of the engine, such as through the comrade on then to the cylinder line, a wall between the piston rings and the cylinder liner. So it's an incredibly important piece off the engine because along the power that we're creating by our pistons or is being transmitted to the Pistons is then being transmitted to the crankshaft. They'll also be bearings at the end of the crowd. Chefs, for example, here about here on the other end, not here on those bearings there to support the weight off the crankshaft on obviously all that power that's being transmitted to the crankshaft. So that's what we're doing here. You can see. Also, we got to support bearings. Just have a look around here. One there, one here. Those are also places where we can support the weight off the crankshaft, these crank webs, although they are there to create the offset required in order that we can move the piston up to top dead centre back down again. They're also there to add a bit of momentum or stored energy, which allows us that you can see here. We've got this entire piece here. When you think about it, this is no really needed because there's our center axis of rotation where my mouse is on. The offset is only two here, so you can see we only really need this half off the crank Web In order to get the engine toe work. However, we add the extra piece here to balance the crankshaft on. Also, it's give us a bit of stored energy so that when we're bean pushed down by the piston, it will also use some of the energy that saved in the crack Web to rotate back around and force the piston back up again. And the fly will does this as well. So that's that crankshaft, and he's going to sit inside the crank case. You'll also hear people sometimes say, I needs to crank the engine, which means to turn it over, or, in other words, to get it to very tape. That's probably where the term comes from. Let's just go back now. Another look at the image of the crankshaft because I've noticed, is actually a piece missing on this freely model. So here we are again. We can see the crankshaft, can see where it connects the load on the end on, we can see also thes spray ports as one to free on four. They're not in the three D model. I'm not sure why we're gonna have to correct that, but those ports would spray oil outwards on. They would lubricate the internal part of the engine, such as crankshaft on. As these crank webs rotate around yours, going to spray are them. Some of it might hit the cylinder liner or the pistons on the connecting rod at least on that, always gonna be splashed around a little bit on. We're going to lubricate all of those moving parts. So that's another ways. Get oil into the engine. Remember, as I've said before, we're not just lubricating were also cooling the engine with your so it's a very important part off the engine. 16. White Metal Bearing: So now we're looking at a plane metal bearing. Just do a little spin concedes, got quite a long body shape here on it also got quite a lives diameter Noticed that the bearing is in two parts. It may be in one singular part. It may be in more than two parts, but the idea with the plane metal bearing is that you can sandwich it onto a journal, for example. Let's say a crankshaft journal on you can do that without needing to slide the bearing down the entire chef. Obviously, sliding a bearing onto a crankshaft is incredibly difficult. It's actually possible because the crankshaft has such a unique shape. So in these instances we use plain metal bearings. There are two main types of bearings playing metal bearings. Andi anti friction bearings, also known as roller bearings. Anti friction bearings include ball bearings till in the bearings, tapered bearings, etcetera. However, in this video we're just going to focus on the plain little bearing. Now I should give you a bit of a warning here that playing metal bearings are also known as white metal bearings. Thin film bearings have been metal bearings, hydrostatic bearings and hydrodynamic bearings don't be thrown off by the terminology. They're all referring to the same type. Off bearing hydrostatic and hydrodynamic are slightly different. I'll explain why in a moment, But let's just talk about this particular design of the bearing so we can figure out how it works. So we've got two parts. We've got another shell on. We have a lower show. We've got ports in the top and the bottom See on the sides here and through these ports, we can pass lubricant. Typically, this is going to be lubrication oil andan an engine. You can expect the lubrication all system to be at around 3 to 4 bar. What's gonna happen is the lubrication oil is going to come into the bearing. Let's say for this sport here on the orders, going to spread out into this groove across the other side. And sometimes you'll even see grooves going this way on a cross CIA Down that way on. This will help you all to spread out across the entire surface off the bearing Now between the bearing or between the two halfs are one of the crankshaft journals. So we're gonna have the journal here inside on, then the outside, we're gonna have the connecting rod or the Conrad. What's gonna happen is we're going to nip the bearing. That means you're going to apply slight pressure to it in order to install it. And then this light pressure is gonna actually push the bearing outwards slightly so that it's It's very snugly with the connecting rod. So the entire back plate here with the backside of the bearing is going to pressed tightly against the connecting rod. However, gonna then have a layer of oil along the inside, here and all on the inside. Here, on this there of all is gonna completely separate, at least theoretically, the bearing from the crank Shaft journal slayer of all is incredibly thin. We're talking literally thousands of an inch, but it's enough to separate the bearing from the crank shaft on. This will stop us then generating friction on generating heat. And he'd It does. Accumulate is carried away by the lubrication oil or the lubricant. Andi, if we get any more heat is generated, is going to be transferred through a bearing on, then onto the connecting rod itself. That's the reason why we fit the bearing so snugly against the connecting rod. Because the clearances are so tight any particles would get between the bearing and the Journal are going to cause damage to the bearing. But bearing itself is made of a very soft metals, his Babbitt metal normally on. That means that any foreign particles Aaron the lubrication oil system or, within the lubricant, they're going to embed themselves or scratch away at the bearing. Now this is good and bad. It's bad because it's wearing away the bearing. But it's also good because we're not wearing away crankshaft, which costs a lot more money. So that is one of the reasons why they make the bearing out of such a soft material. But it's also the reason why it's imperative to keep your lubrication oil system very, very clean. The tolerances between the bearing on the Journal are incredibly fine, and that means any particles that end up between the bearing in the journal our guns cause damage to be bearing. If you hear the phrase hydrostatic bearing that simply means that using a pump to generate pressure in the oil system on if you hear the phrase hydrodynamic bearing it simply means that there is no pumping operation and it is the momentum off the engine itself. Or, for example, a turbine which causes your film to be maintained between the bearing in journal. So hydrostatic has a pumped hydro dynamic. Does not have a pump for many applications. It's actually possible to have a mixture of the two where you'll have a pump that start up and then you will no longer require the palm. Once everything is running full operational speed, these engines themselves will use an oil pump on. The pressure you achieve will be between 3 to 4 bar. If we have a look on this image here, you can see where the oil is being supplied to the bearing on we can see The bearing, which is highlighting Green, is separated from the crankshaft by this very thing. Oil film. We can also see that the oil film gradually spreads out across the bearing, separates the crankshaft from the connecting rod so that we don't get any friction and heat and robbing etcetera, and then you're literally leak out off the sides or you'll have some form of all spray spraying out from the gap between the corn rowed on the crank. Chef 17. Flywheel: flywheel. The flywheel is located on one end of the crankshaft and serves three purposes, one due to its momentum or inertia on weight. It reduces vibration by smoothing out the power Strokers. Each steel in the fires to it sometimes serves as a mountain surface used to bolt the engine up to its load. Three. The flywheel has gear teeth around its perimeter that allowed the starter motor to engage and crank the diesel. So there we go, said he crank the diesel Sam's crankshaft. But let's go down further. We can actually see. In fact, we'll have a quick look of the image. Here's a flywheel on the end. We've got a gear teeth where we engage the starter motor. We've got a three D model of this, so we'll load that up in a moment. The fly wheel diameter is usually large, as this allows it to rotate further from the crankshaft center axis of rotation, which is an imaginary line that runs through the middle of the crankshaft. The increased diameter also made it easier for the starter motor to rotate the engine. This set up is similar to gears on a bike, a low gear requires a larger force to be applied in order for the wheel to rotate, whilst the higher gear requires less force. But the amount that wheel rotates is less so. That's how fly we will consider. Peace here will load the model up in a moment, conceive the three main points due to its momentum away. It reduces vibration by smoothing out the power stroke as each cylinder fires. I would say that one off the main reasons, rather in a flywheel to sometimes serves as the mounting surface used to bolt the engine up to the load again. That's also true, I would say sometimes, though, that you don't always have to have a flywheel. So point to is perhaps not essential in this case. Free The Fly will has gear teeth around its perimeter, allowed the starter motor to engage and crank the diesel. Once again, this is one of the main reasons for having a flywheel. Let's load up the fire wheel model. It's incredibly basic, because the fly will itself is quite a simple component. There is an equation to calculate how much stored energy you would have in a flywheel when it's rotating at a certain speed or a certain number of radiance per second. But you need to know the diameter of the flywheel on its weight on, then. Also, the speed you can calculate how much energy is stored within the flywheel won't go into that right now because I don't know the equation of top of my head and prepared that just yet. But if we look to the outside, we can have a look here. We've got our teeth. These gear teeth will engage with starter motor. Start tomato rotate here it pushes the Getty. The long, I'd say in the tours, the left hand side. So we're going in the anti clockwise direction. Perhaps clockwise doesn't really matter, Andi. Then we're going to rotate the engine or crank the engine, conceded the shape of the fire will. It's quite thin. It's got a large diameter. You want it to have the lives diameter because the amount of force that you're applying to rotate the ageing could be affected by the distance. The rotational point is from the engine. What I mean here is if we've got a small flywheel, let's imagine along this circular space here, so the dark circular line. If that was a flywheel, we'd have less stored energy. But also, its most extreme point of rotation is here where the black line is now. If we were to increase, maybe fly will larger, So increase the diameter, then the amount of force that we're applying onto the engine increases because the point of rotation is further away. Now, this is a little bit like a seesaw motion, so it's actually called the moment. So moment is force multiplied by distance. So what? We'd have for example, imagine at a C sore in your park or somewhere nearby in a park if is a pivot point and one person stands one meter away from the pivot point on one person stands another meter away from the pivot point on a sea story is similar to a straight long piece of wood, for example. So you're both standing on this straight piece of wood, each a meter away from the pivot point on both people weigh 80 kilos. Well, you're gonna balance each other out on the sea sore, or this long bean piece of wood is gonna be horizontal because you both weigh the same. And now, however, if you were to put one person two meters away from the pivot point on the other person want me to away from the pivot point, you wouldn't balance each other out despite the fact you're the same weight. The person who's two meters away from the pivot point exerts a bigger force because they're further away from the pivot point. So one person who's two meters away as a larger result in force than the person who is only a meter away despite the fact they have the same weight and it's the same for a flywheel, except we're applying the force in a radio motion. So if we've got a point here, the maximum diameter, the flywheel to the black line, then the force that were exerting the rotational, angular motion of exerting is less than if we have a flywheel of a larger diameter. So that's another reason why you want to fly well with a larger diameter. They also make flywheels quite thick. Sometimes on this is to store more energy because we have a larger mass, Then we've got effectively Mawr Mass that goes into motion or has momentum or inertia on. This is then harder to stop. Remember that a body in motion takes a certain amount of energy to stop on the larger that body use, or at least the more mass it has, the more energy you will need to slow it down or stop it On DSO. We have a thick flywheel with a lot of stored energy or, relatively a large amount stored energy on as it's rotating a set speed. It's gonna help those pistons be pushed up as they compress the air and then as the fuel is injected. So instead of the pistons offended all the work themselves or compressing all of that air on their own. The flywheel is helping because it's already stored some of the energy that the engine created earlier when we had our power stroke. And then we're going to apply this energy that restored to force the next piston upwards on to generate more power. So that's what we do with our fly will on. The result in effect, is that the entire combustion process is smoother and we have a lot less vibration. We can see. We've got six holes. 123456 so we come out and external load onto the fly will if we want. And as I've mentioned already, you can see we've got the flywheel Getty, and that's where we would attached a starter motor in order to crank the engine and get it started in the first place. You only ever need the starter motor to rotate. The fly will get the engine started. After that, the starter motor will disengage. I want its disengaged. Then the engine will continue under its own power. There's no power to start the engine because we can inject fuel, but there's no compression. So in order to get around, this will use a starter. Motor euro tasty engine does the first couple of power strokes and then the start. A motive will disengage on the engine will continue then, because as enough momentum to perform the compression ignition cycle, which we'll talk about later on the course. So that's why I started motors doing, and that is why we require in the first place very important. Know that started motor disengages because if you don't disengage the starter motor or if you have a problem, then the teeth here will be stripped back and you will either have no flywheel teeth or no start immunity. So it's really important that you remove or disengaged starter motor I have at it. In the past, where the starter Motor remained engaged, we had a problem with the solenoid valve that pushes the starter motor out and engages it with the flywheel on. Yet by the time we realized what had happened, the starter motor was more or less destroyed, or at least the gears were. 18. Cylinder Head: sealing the head. A diesel engine cylinder head performs several functions. One, the combustion space could be considered to have free walls. These are the bottom, which is the piston, the top, the cylinder head and sides sealing the liner. The cylinder head provides the topsy over the cylinder bore or sleeve to the cylinder. Heads provide the structure of holding the exhaust. Gas valves, intake valves be fitted and fuel injectors for large diesel engines. Each cylinder has its own head casting, which is bolted to the block for smaller engines. The engines head is cast. Is one piece a multi cylinder head. Diesel engines have two methods of admitting exhausting gases from the cylinder. They can use other ports, valves or a combination of both. So have a look here can see a two stroke engine using ports and valves. We've got air coming in, and we got the exhaust gas files on the top, and we're going through the different parts of the cycle. Here. We've got the in take part in the exhaust gas. It's known a scavenging when we're taken Arian and exhaust gas being discharged out. Then we guard compression stroke, where we're compressing the contents of the combustion chamber. And then we got a power stroke where we ignite the fuel on. We get combustion on, we get a controlled explosion on that forces. The piston downwards ports are slots in the ceiling, the walls located in the lower third of the ball. When the piston travels below the level of the ports, the ports were opened and fresh air or exhaust gases are able to enter or leave, depending on the type of poor. Reports have been closed when the piston travels back above the level of the ports, so we can see we've got different means off scavenging for the process of getting area and exhaust gas out what refer to scavenging? But this lesson is actually about the cylinder head and as we mentioned before, whereas we might use the system for the lower part of the seal of the combustion chamber on will use the cylinder liner for the sides will use a cylinder head for the top. The cylinder head provides structure, folding the exhaust gas valves, the intake valves on the fuel injectors. So essentially, when we've got sides of the combustion chamber and we've got the bottom of the combustion chamber that we need. A top on the cylinder head forms the top several it now at the three D model. This is for a two stroke engine. There's three different means of scavenging for two stroke engines. Thes are loop cross and union flow. Let's have a look at the 1st 1 can see require crankcase Got the piston gotta valve here It's called re valve and then we're gonna let the air fuel mixture through the valve. Yeah, fume extraction comes up for a year. We've actually got this model is Afridi model on the pdf that I've given you as well as an animated two stroke engines. So make sure you check that out as you see it's coming through were scavenge in some off the mixture. Air fuel mixture will escape, but the bits that don't escape will be compressed. And then we'll get our power stroke. Also notice we've got a spark plug. A top on the sparkplug is used for igniting the fuel. So this is not a diesel engine because a diesel engines are compression ignition engines. They're not spark ignition engines, so this is a key indicator that we're dealing with a petrol gasoline engine. On the other model, we've got a union flow type of scavenging arrangement. This is primarily used for very large. Two stroke engines resume in. We can see here. We've got the air coming in. There'll be some swirl that's imparted is here comes in as well, which gives us a good movement of air as it travels through the cylinder on. We've got a exhaust gas valve at the top on. We're gonna draw the area, is gonna push out the exhaust gas, and then we're gonna change the exhaust gas that is within the combustion space for the air or the charge air. And in order to ensure we've got a full cylinder of air with no exhaust gas, we're gonna change him out there within the combustion space a lot. Typically, you will scavenge 30 to 70 times mawr air going in in order to ensure that you're flushing out the exhaust gas. So we're not just having one or two times the volume of this combustion space were flooding it with their As I say, maybe 30 times the volume of air is actually needed on. We're gonna flush out all of the exhaust gas on the big benefit here we can actually see. This is a diesel engines who got fuel injectors is one, and there's the other one. But the big benefit with this type of scavenging arrangement, which is the most efficient type of scavenging arrangement, is that we can get the exhaust Gasol, and we can control exactly when we want the exhaust gas valve to open. Because we attach an electromagnetic valve or hydraulic valve on the top we can control, then exactly when it opens and closes. That's not true with the other scavenger modes we look over here. There is no valve on decide, and there is no valve for the loop flow type, either. And that means we can precisely control when the exhaust gas valve opens and closes. And this is a big problem. This is why two strokes and are sufficient as four strokes or one of the reasons. It's because we're flushing out a lot of the air and fuel mixture, especially for this side. Andi. Some of it is wasted. We're sending in. It's gonna be wasted on discharged to the exhaust gas port before it's done. any useful work. Where is on a union flower arrangement? We can see that we inject the fuel only when we really need it. And we flushed out all of you towards guess on that two stroke petrol arrangement we've taken in the air fuel mixture. Andi, some of it has escaped. The piston travels upwards on, then will ignite the rest. But the power stroke is far, far shorter than the power stroke on the unit flower arrangement. So the timing on the diesel four stroke engine or the diesel to strike engine this case could be much better controlled them for a standard two stroke petrol gasoline engine. So that's the main reason why four strokes are more efficient than two strokes, and that simply because you can control the timing a lot better. It's another reason why to strike engines have primarily used only for smaller or very large applications. Small applications because it doesn't matter too much if you waste a bit of energy, whereas bigger applications you modified a design slightly, so you have, for example, a union flow design on that makes the engine more efficient. However, you couldn't install this unit flow valve on a smaller engine because as a hydraulic system andan electronic control system. So for smaller engines, they just say, Okay, we'll keep your basic and just accept the fact that the power to weight ratio is quite high . But we have an inefficient engine, and that is essentially a petrol to strike engine. 19. Intake and Exhaust Valves: intake and exhaust fouls. Valves shown below are mechanically opened and closed to admit air or expelling source gases. The valves are located in the head casting of the engine, the point of which the valve seals against the head is called the valve. See, most medium sized easels have either intake ports or exhaust valves or both intake and exhaust valves. I see you've got a poppet valve foul reason with tips before we look at the valve. Tip one. The type of valve shown is sometimes referred to as a pop it or mushroom valve. Stick to loop. Scavenging is sometimes referred to his backflow scavenging. So back for scavenging. I'll be honest. I've never heard that term before, but they say some people do say backflow. I've only ever heard of Luke type scavenging Andi Poppet valves. I have heard all the mushroom vows is also an appropriate name. So let's load up our model of the poppet valve. We can see that we've got the stem. It's his section along here. We've got the Filip. That's this section. We'll zoom in a bit more, this section along here, so it's from the stem to here and Then we got the valve seat section here. The valve C has a slightly different angle can see here. It's coming along this way and then it changes slightly. The angle. The reason we are they shallower angle is because we want the valves see to seek correctly , because this is what's stopping the exhaust gas or the air from passing through the valve. So it's important that this area from here to here is very clean. If it's not clean, then we won't get a good seal. And that means we're going to get air either leaking into the combustion space or perhaps exhaust gas leaking. How so? We don't want that because we won't achieve our maximum pressure. Let's just go out with a bit more and see on the bottom. It's very round. You'll see these type of valves in another lesson later on, you'll see they're very round. I think it's in the turbocharger lesson where I explained how the turbocharger works in the turbocharger air system. But essentially that valve is going to be lowered and raised another cylinder head, which is in line here with C and if the valve is pushed downwards, the valve is open on. As soon as the valve retracts upwards, it's gonna press against the cylinder Head on will get a seal, which then allows us to star compression and power stroke etcetera without leaking any gases into or out of the combustion space. That's the valve. Quite simple. Piece of say, they gonna be poppet valves or mushroom valves, but that depends on how people refer to them. 20. Timing Gears, Camshafts and Valve Mechanism: Timing G's camshaft on valve mechanism. In order for a diesel engine to operate, all of its components must perform their functions very precise intervals in relation to the motion of the piston. To accomplish this, a component called Camp Shaft is used. The blowing mid shows a camshaft in Camp Chef Drive gear. So here is that camshaft. We can see that it's straight. There are no bits sticking out the side or their off away from the center axis of rotation , so everything rotates around the center axes. Crankshaft does that as well. But obviously the crankshaft was slightly unusual in its shape because some pieces are offset. Not so here with the camshaft you've got camshaft lobes will talk about in a moment. We got out journals, which, aware we would attach the bearings. So 1234 and five I've got a drive gear on. That's what we use to connect the crankshaft to the camshaft on. Will do that fire a series of gears, right? We'll load up that three D model shortly. Let's just get through his article or through this lesson. It's quite a long lesson, compared some of the others camshaft is a long bar with egg shaped eccentric loaves, physical cam loaves, one loaf for each valve and fuel injector. Each low has a follower as a cam shaft is rotated, the followers forced up and down as it follows the profile of the cam lobe. The followers are connected to the engines, valves and fuel injectors for various types of linkages called push rods. Andraka Rahm's the push rods of rock or arms transfer. The reciprocating motion generated by the camp shop lobes to the valves and injectors. Opening and closing them is needed. After the valves have been forced open by the rocker arms, the valves air again, closed by springs. So we'll see here. Here's a push wrote is a rocker arm Got a valve? Spring the valve. Spring returns valve back to its position. When we take away the force applied by the rock around, we'll see all this in a moment. We've got our valves that's gonna be our inlet valves and exhaust valves on. Then we've got a cam shaft, which is in the middle here on pushes the push rods up and down well, low that freedom model soon because they were just read through all of this text first, and then we'll get to the models. Both train as the valve is opened by the camshaft. It compresses the valve spring. The energy stored in the valve spring is then used to close the valve. A Zicam chef, Loeb, rotates out from under the follower because an engine experience is fairly large. Changes in temperature. You g ambient to normal. Running temperature of about 190 F. Its components must be designed to allow for firmware expansion. Therefore, the valves, push rods and rocker arms must have some method off allowing for thermal expansion. This is accomplished by the use of valve lash valve lashes, the tone given to the slop or to give in the valve train before they can actually starts to open the valve. So valve lash is the term given when we have a space between the valves on the rocker arm or some sort of spacing to allow the thermal expansion. What we'll actually do is take tap it clearances. That's where we put feeler gauges between the valves till the top of the valves on between the rocker arm on these tapping clearances allow us to measure how big the gap is between the raw Karam on the valve. And then when we're adjusting that weaken said it correctly so that when the engine heats up, there'll be very little give or very little slop between the valve on the rocker arm. So that's the idea. If it's set incorrectly, then you're gonna have a bit of a chattering noise, like a kind of noise that comes through and it seemed very fine. It's very quick. It's a bit like a vibration kind of noise. But with our high tapping noise on this tapping noise happens quite quickly is as the rocker arm impact with the valve and you'll get this. But obviously that's happening very fast, so you get quite a constant noise. So you've got to make sure that you're tapping clearances or your valve lashes sit correctly so you don't get up. The last thing you want is one piece of the engine impacting with another, so you'll reduce the valve lash as much as possible. We'll have a look at that when we look at the three D model idler and timing gears. The camshaft is driven by the engines crankshaft for a series of gears called I'd leg Use and Timing Gears. To give is allow the rotation of the camshaft to correspond with the rotation of the crankshaft. The gears thereby allow the valve opening valve. Closing an injection of fuel to be time to occur at precise intervals in the pistons. Travel to increase the flexibility in timing the valve opening valve, closing an injection of fuel and to increase power or reduce costs. And engine may have one or more Camp chefs, typically in a medium to large re type engine. Each bank will have one or more camshafts per head in the larger engines, intake valves, source files and fuel injectors may share a common camshaft or have independent camp chefs we can see on our example. We got a single camshaft here, but it's not unusual to have one on each side or perhaps one just on the right side really depends on the style of the engine number and locations off camp chefs, depending on the type of make of the engine, the location of the camshaft, or shaft, there is the camps after an in line engine is usually found either in the head of the engine or in the top of the block, running down one side of the cylinder bank on smaller midsize V type engines. Camshaft is usually located in the block at the center of the V between the two banks of cylinders in larger or multi cam V type engines, the camshaft usually located in their heads. So it's er, engine, I would say, is mid sized or small on. We have a single camp straight down the middle. And as the camera tapes, he's gonna push the camp, follow up on the push rod, ongoing open and close the valves. Well, look at that in a moment. In fact, we can look at it right now because we're actually finished this lesson. So let's load up the camshaft more. Have a look at its design and how it works. It's quite an interesting piece, I think, on the machine. Let's have a look. We can see we've got a drive trained. In fact, it's just a little spin. First, we can see it has a center axis of rotation because we can literally look straight down the shaft. There's no sticky out bits, nothing offset. We've got these cam lobes is shaped like eggs. 1234 And there's 1234 on their on 1234 So there's 12 cam loaves in total. And then we've got a Dr Gear. This one here on that engages with the second years, which will then engage with the crankshaft. So as long as the crankshaft is turning, camshaft is turning important to realize that the speed of the crankshaft directly relates to the speed of the camp chefs because they're linked together via gears. If for any reason they got out of sync, you're gonna have a problem, because Camp Chef is gonna be out of sync with the crankshaft. And that means the timing of the engine is all out of sync completely. So you're gonna valves opening, closing when they shouldn't be. However, that's not really a typical problem for gears. Gives a very reliable if you're using a chain or anything like that. Change tend to be long gate over time. And that's one of the reasons why you'll try not to use a chain where possible when connecting the crankshaft camshaft. However, for very large engines, you do use a chain on. They take chain deflections or the measure the length of the chain. Estimate the chain How much slack is in the chain, and from that they can see if the engine timing is correct or not. If you get a problem with your engine time in your notice IPO fairly quickly because you're not achieving the power out that you want the power output because you're not getting the maximum pressure that you want. It might be compressing all the gases within the combustion space, but they're gases a leak and passed the valves. Maybe because the valves aren't shot yet because camshaft is no correctly timed. We'll have a look at that in a minute with an animated engine. Spin it around a second, so we got all of that can lobes. 1234 on again the unique egg shape. The reason we got four on each section is because our engine is a the six, so there's gonna be two for one side and two for the other side to for one side to the other, two for one and two for the other on. We can look at that in a moment on our animated engine. But essentially, as this cam lobe is coming around, you see, it's got this sticky outpointed bit the point a bit of the egg or the cam lobe. He's gonna push up a camp follower, and that's what's gonna cause our valves to open the rest of the camshaft. He's more or less split into places where we can add bearings for support, such as here on here on that is more or less it. The camshaft has to be lubricated the same as many other moving parts of the engine. On this reduces friction, which ultimately reduces heat. So let's load up the animated engine now so we can have a look at all that. Okay, so here is our animated four stroke diesel engine. Six cylinder. I don't know how many vowels before 8 12 looks like 24 valves in total, and that means 12 inland and 12 exhaust this zoom in a moment there is our piston, but for this lesson, we're gonna be interested in the camshaft. So here is Ah, camshaft. He's going along here. Glad cam lobe. We got a series of other loaves that go all the way along the camp chef. We saw those earlier but notice guy can Follower, I've got to say I'm the smaller type of engine You not gonna have a flat camp follower like this is gonna be rounded. The reason it's around it is because you want to gradually apply the pressure from the cam lobe onto the camp. Follower, You do have flat footed camp followers, but not for smaller engines. Or not that I have seen what really out. Completely excited seeing every type of engine. But normally they'll be round and you'll be able to push them up and down on the round shape means that you're applying the force uniformly rather than as it's seen here. Anyway, let's press play and see what happens when it comes around. Okay, so we've lifted up, can see that we have lifted up using our cam lobe, this camp follower. Then we've applied that linear movement off puts to the push rod. The push rod has then pushed up this piece year the rocker arm which is pushed down on two valves. So look, you can see it pushed down. So the pivot point was was here. Push that down when it pushed down, it forced down the valves. See the valves here. And if we push play, maybe we can figure out what point? The cycle. It's up. Okay, so the system was traveling up, so it's exhausted. Exhaust gas out of these two valves. We're now gonna go back down drawer, Aaron, you could see these two valves. So that one two in the background, they were open. They have now closed engines gonna come up for its power stroke. Causal. The vows that closed Andi, get the power stroke on. Then exhaust system will come back up again. So that's what the camshaft is doing. Its allowing us to open and close these valves at the correct time again, let's push play. Okay? Watch this piece here, where the mouse is up it goes, and again you see it coming back around. You can see that linear motion pressing those down. And we're open the exhaust gas bottles at the right time, opening the air inlet valves at the right time because the air inlet valves also have their own cam lobe. And that's essentially what the camshaft is doing. We may also on older engines have in fact, not just on old engine by larger engines as well. We may also have a camp chef that controls when the fuel is injected, but generally on new engine. She going to use what's called a common rail fuel system. And that's where you have a solenoid valve or electromagnetic valve attached to the fuel injector or very near to it. And you will control. Then when the fuel this is where our fuel comes in through this pipe here, your control. When the fuel goes to the injector, we consider inject. Aries is there. When the mouse is on, the electromagnetic valve will open or close on. That will allow hydraulic fluid into the injector, which controls when the injector opens or closes, which controls when we let fuel in to the combustion space. So common rail simply means that we're using a hydraulic fluid to control when our injector opens and closes. And if we can control when it opens and closes, then we're controlling the amount fuel on board when fuel injection occurs. So when fuel injection occurs on the amount of fuel that is injected. So that's common rail. However, Cammarelle might not have that on this engine, we do have common rail fact On the top of the fuel injector, we can see there is a new electronic connection here, and that's because we have an electromagnetic valve solenoid valve. We will connect that to an electrical supply on that single new control, specifically when the fuel injector opens and closes. So that's a giveaway. If you look there, you can see if you have a common rail Injun or not, because you can just gently electrical connection. You don't have an electrical connection. You don't have a Conrail engine. But if we come back to Camp Chef, if we were controlling the fuel injection from the camshaft, we would have another cam lobe on the camshaft. And that would be doing the same job as what it's doing here for the valves. Except that it would be pushing up and down a camp follower in order to inject fuel into the combustion space. So that's why I can't Chef doing very important concerning timing. Without the camshaft, it's quite difficult to control all of the vowels and the fuel injectors, etcetera. However, I will say there are a lot of the electronic control units out there now, and the trend is that wherever possible, you want to remove the camshaft. Now it sounds a bit drastic when you start taking entire pieces out of the engine, but is a logical reason for this. The mawr pieces that you have on an engine, the more it weighs now in order to increase the power to weight ratio. Ideally, you want to take away as many pieces as possible because every one of these pieces that's moving and you can see there are a lot of them is sucking a tiny amount of energy away from the power that we could be using for our load. So if I attach more and more pieces onto the engine at some point, is going to stop rotating because all of that power has been consumed by the engine components. So if we reduce, the number of engine components will get more power transferred to our load. And that's the reason why it's a good idea to remove as many parts as possible. Remember, if you got no camshaft, then you don't need any camp. Followers don't need any camp followers, and you definitely don't need any push rods and you don't even need any rocker arms. What you need instead, or a couple of solenoid valves, one for each inlet and exhaust valve on bacon control because they're electromagnetic valves they can control. When you're inlet and exhaust valves open and close on day. Wait far, far less than all of this other equipment. All of these other components that you have here. So that's gonna be the trend going forward, where possible from with anything? No, that's Elektronik is It's very prone to failure if there are small disturbances, especially the electromagnetic fields, etcetera. A mechanical engine is my opinion, very reliable. It constructed nowadays from very strong parts that have been tested and tried and tested a lot over the past 100 years. Elektronik controlled engines. They are not as tried and tested on. It only takes a few 1,000,000 volts of disturbance in the electronic circuit to really create havoc with the engine. And I'm speaking from personal experience here so personally, wherever possible. I know people don't like stinky old tractor engines that make loud noises and puff out black smoke. But the reason that you see these tractors still going today is because they're reliable. You really can't kill them. They don't have much protection, such as hi Lubell, temperature alarms or anything like that. But they just keep running. If I took a modern engine nowadays on, perhaps the control unit was broken after five years, it would be almost impossible to repair the engine without having the parts available. So I need an electronic control unit and I need a technician to come out and program the engine. So imagine for a moment that society collapses and all that stuff is no longer available than the thing that you really want is a very old 19 sixties, fully mechanical diesel engine. You don't want all the technical electro gadgets etcetera, but the trend is the electron ICS are coming through more and more on engines of being controlled more and more Bay Electron ICS. It's simply more cost effective because the engines do have a greater efficiency than they did in the past. But we're talking here about a couple of percent maximum. So anyway, that is Cam Sheftel don't have a little spin. I hope you didn't die aggress too much. There I try and stay focused, but This is a lot of ground to cover sometimes, and I think some of the stuff quite interesting. I apologize if that's not true. If it isn't Samir comment and I can trim these videos back one day. But as I can shot straight down the middle, controlling all of the valves. What s coming? Next listen. 21. Blower: blower diesel engines blower is part of the air intake system and serves to compress the incoming fresh air for delivery to the cylinders for combustion. The location. The blow is shown on the blow images. The blower could be part of over a turbocharged or supercharged air intake system. Additional information on these two types of blowers has provided later in the course. So our blows on the back off combustion engine. We can see it here loaded Freedia model at the end, and we can have a look at it and we can see there as well. This is a turbocharger. I know this because it's connected to the exhaust system on one side on its connected that that would be the usual system here, and it's connected to the air system on the other side. For me, it is there a system that's here going into the engine, and this is the exhaust coming out going to the opposite side. So that's a turbocharger. Got separate lessons for turbochargers and superchargers, so I don't stress. We're gonna get to that. Let's load up this model quickly. They run low, not this model. Just have a quick look at the blower. The blow is just kind of a fancy name for saying, Fan, it's the thing that blows air into the combustion space. Now remember, we need air for combustion. We can't just use fuel, so it's still a little spin of our engine. This one is also available on the list in the pdf. So check it out. If you click here is well, you can also check out all the various components of the engine. And now I think this one's quite good, in a way, because you're seeing the engine as it usually is if you go to the other models, you've seen stuff like pistons and piston rings, but you're not going to see that in a day today basis. Are you actually gonna see on a day to day basis? Is stuff like this the rock around, cover the exhaust gas manifold, etcetera. There's a little description there which you can check out. So let's do a spin. Now Let's find out. Blower. I know I keep die aggressing, so I'm gonna try so focused in this lesson, there is ah, lower. It looks a little bit like a snail, which are, say, a few times during this course, there is snail shape, depending on how Walk division is was sucking in there, here, being discharged into the engine and we get in exhaust gas out. It's going to the opposite side has a say We'll talk about later on the turbocharger lesson . But all you need to realize for this lesson is that the blower is responsible for getting air into the combustion space. If we have a blower, we can get more air into the combustion space because we compress the air. If you compress the air, then you get more oxygen into the combustion space. You get mawr Mass or a greater massive oxygen into the combustion space. If you got more oxygen, then you can add more fuel. And if you've got more fuel and more oxygen plus the heat, then you get combustion and you'll generate MAWR power. So, essentially as long as we can keep this air to fuel ratio oxygen to fuel ratio, correct. Then we're gonna get some very efficient burning, and that means we're going to generate Mawr Mawr power. There's no point injecting load into the combustion space if the oxygen isn't there we're not gonna be able to burn the fuel. So the blower helps us to get the air into the combustion space on burn the fuel. Okay, so hopefully that's all clear. I'm sorry if I have to stress some of these points, but I think it's important to realize you want that air in there to burn the fuel efficiently. I mean, it's easy to burn fuel without doing it efficiently, but to do it efficiently is a different are all together. And that's why we compress the air will force more air into the combustion space as a side note as well. If you have black smoke coming out of your exhaust, this indicates that you're burning too much fuel compared to the oxygen to fuel ratio. In other words, if you put in too much fuel in a combustion space on its not being burned correctly, you're gonna end up with black smoke. If you put too little fuel in the combustion space, you're gonna end up with white smoke on def. You burning lubrication oil, you're gonna end up with blue smoke or blue exhaust gas so black, too much fuel, way too little fuel on blue lubrication oil. That means you're burning the lubrication or from the cylinder liners and the piston rings . What should be lubricating the space between your piston rings and cylinder liner? So we talked about that earlier. Obviously it only burning off too much lubrication oil. Because if you do that and you might get the piston rings rubbing against the lineup, so anyway, it's like digressing again. But I'm gonna stop apologizing something us some good information. 22. Diesel Engine Support Systems: diesel engine support systems. A diesel engine requires five supporting systems in order to operate water, oil, fuel, air on exhausts, depending on the size, power and application of the diesel. Thes systems vary in size and complexity to it's now becoming more common to include the electronic control systems part to supporting systems list. The reason for its inclusion is because engines have becoming more reliant upon Elektronik control in order to increase efficiency, which reduces costs. The electronic control system can render a camp chef redundant as it can control the opening and closing of valves as well as the timing of fuel injection. The downside to this technological advancement is that any failure of the electronic control system will often render the entire engine inoperable. Okay, we discuss that in one of the previous lessons, particularly camshaft lesson. But I would say the electronic control system is now a part of support system. If you've got a problem with your battery or anything like that, then your engine simply won't work. Water, oil, fuel, air on exhaust. These are the material sides, the liquids and gases that flowing around your engine that make it work. The Elektronik side is more just the electrons flowing for your electronic circuits. However, I will say this support systems or systems in general very, very important to learn or to learn what's within the system. When I was sailing on a container ship when I was about 17 the second engineer on board all he ever used to say to me when he did speak to May was no. Your systems know your systems know your systems, and that was pretty much all he ever said. Andi, I never really realized at the time what he was talking about, but I know I did my head and agreed anyway. But what he meant was, no your systems in a case of knowing the system itself on all of the components that within the system. So I know, for example, that a system or most systems have a liquid will require a strainer onda pump on a few valves. So that's all gonna be involved or apart off the system. So if I take my knowledge that I know from an engine, I'll show you how we can use it. Once we know what a system is, so use I engine again I'm gonna load up this model now. I know the exhaust system. I noted lubrication or system. I know the cooler water system. I've memorized the parts that are involved or that make up the system. Andi, I'll show you why it's important. So if I look here, I know that is gonna be some exhaust gas coming out the engine. I've got locate where that would occur so that some pipes connecting here, this is one manifold. I know that there's a ceiling, the line or a place where the piston's gonna be housed. So they're gonna be inside here, further down. So underneath the rocker arms, etcetera. But where is the exhaust going out of the cylinder where it's either going to be the top or it's gonna be at the bottom. So let's analyze it a bit further. If we know the system that we know that the air is cooled down prior to entering the combustion space, we'll talk about Anna Togo, charge a lesson. But I know that just from experience, So I say Okay, so the air is coming in. This is Kula. I know from the appearance of this is a cooler on the air comes in on. It's gonna be cool down prior to it going into the combustion space. So I know this is all air system. It's an air system, this piece for the air system. So this is also for the air system that can see the manifold here on a CSI. It discharge into the cylinders. So that makes sense because each cylinder requires there. That means that if we got air coming in on one side, it's highly likely the combustion exhaust gases where the exhaust gases, they're going to come out on the opposite side. And if we follow that exhaust gas pipe around and I can see it connects to the opposite side off the turbocharger. So it comes up here, Andi, that connects to what we call a turbocharger turbine, which we'll talk about later. So I just traced out there the entire air on exhaust gas system. But I also know from working on, for example, centrifugal pumps. The air is drawn in through the center. This shape that we're seeing here, this snail shape who followed my mouse going around. This is a typical shape for a veloute casing. They have those on centrifugal pumps. Veloute casings convert velocity to pressure. So I know from experience as well that we would draw whatever is flowing through here in the middle and it is discharged on the outside, and that gives us a change in velocity to pressure. So I think. Okay, so this air going in here, that makes sense for going the other side. But we have a semi veloute casing again. But this time it looks like if we were sucking here in going that way, would it make sense? Not really. It's going straight to the combustion space. The reason it doesn't make sense is because we actually compress the air in here in the temperature increases. So we call the air down after it leaves. So this wouldn't make sense on this side. But I know this because I know the systems. So I know the air system. I know the components involved, such as the cooler in the turbocharger on don't know the exhaust gas system of what's involved, and I would hope as you progress through the course, you will also identify some of these components on the engine, and it will give you a good indication to which system that component belongs. Another thing that I always have to stress here, which also you will learn in this course, is that I don't want you to learn anything just by memorizing it. There are some useful things he can memorize, such as the number pi 3.14 But realistically, engineering about thinking you should be able to see things and think through the problem. So rather than just memorize everything, should be able to look at it and say, Okay, I saw this somewhere else. Or I know from the lesson that I did with John or the course I did with John that the song fundamental engineering principle that we can apply here etcetera, and then you can think through until you reach the logical solution. So engineering is definitely more about thinking, I would say than just memorize and stuff andare really over. You can do that after finishing this course, so I'm not digressed again. Both flee. That will give you a bit of motivation to learn your systems, learn the components and then apply sound engineering logic to think about where these components are on what systems they belong to 23. Engine Cooling: engine cooling. New diesel engines rely on a liquid cooling system to transfer waste heat out of the block and internals. The cooling system consists of a closed loop similar to that of a car engine, and contains the following major components. Water pump, radiator or heat exchanger water jacket, which consists of cool and pastures in the block and the heads on the thermostat. We can see on Freedom Model now that we've got a thermostat, go pump expansion tank on a heat exchanger, which is a posh word for a radiator. In the next lesson, we're gonna look at this entire system and see how the cooling water system works to. A cooling water system is also referred to as a jacket, water cooling system or jacket water system. There is technically no difference between the three expressions. The jacket refers to the space around the cylinder that is flooded with cooling water. Think of a jacket that you wear. It's the same for the cylinder. The cylinder wears a jacket of cooling water, so that's our engine. Could award system short lesson here because we're going to discuss most of how this works and why you have a cooling water system in the next lesson, 24. How Engine Cooling Water Systems Work: in this video, We're going to look at an engine cooling water system. I'm gonna explain to you how we regulate the engine crew, the water system temperature in order to prevent the engine overheating. As you can see here, we've got a three D animation we're actually looking at is a four cylinder in line internal combustion engine. I got four pistons on two free four and they're in line. Go to crank chefs and the cramp chef connects to an axle fan inside of here. Notice the fan is actually driven by the crankshaft itself. We've also got a jacket. Water pump. It is exciting. A thermostats besides him Here, Andi. Then we have a radiator. This is effectively a heat exchanger on expansion tank on all the associate ID poses on piping. So what we'll do? We'll dive straight in on I walk you through. What happens when an engine starts on? We'll look at the components as we go along. So let's play the animation briefly. Okay. You can see our animation. You You see, the engine is cold. These blue arrows indicating the cooling water system is cold. Get rid. Hours indicates that the Cudmore system is becoming hot or is hot. We can see that the arrows are flowing around the combustion space around the cylinders. That's why we call it a jacket. Water system, a jacket, water cooling system and a cooling water system are the same thing. So I don't get thrown off by the wording, Jack. It just means literally that the cylinders aware in a jacket and that is to keep him at optimum temperature. What? Do a pause, the animation Zoom in. I can show you what's happening. We have a cooling water, pumps this up here, sucking from the jackets of the engine on. Then we're going to send a cooling water to a thermostat. Now notice that the engine is cold. So the firmness that is actually going to send the cooling water down. This way, we'll see if I can get a narrow. There we go. Big flow is coming along on down here. We look at the thermostat in more detail later, so don't worry too much better now, but the water is going down on it is bypassing the heat exchanger. Will the radiator come to me and it bypasses are radiator on it is recirculating. The reason it's recirculating is because we're not always trying to cool the engine. We want to regulate the temperature of the engine. That's the idea. I'm cooling water system. We want to maintain the optimum operating temperature on this is gonna be around 80 degrees Celsius. That's what's happening when the engine is cold. So we've started the engine. It's cold in the moment, but as it continues to operate, it's going to generate more arm or he's at some point we're going to see those red arrows coming through and there we go. We can see now The red arrows are coming fruit, so the engine is hot, but notice straight away. The red arrows are being diverted to the radiator. Let's zoom in on that. We can see now that the firmest that has changed position. The lower piece, the lower pipe, is now blocked. Thermostat has blocked that piece off. However, the top bar the thermostat is now open. Concede is a gap in the top, and that is allowing the flow through the top off. The firmest are the flow, then is going to the radiator, and we're cooling that cooling water down because this man is driven from the engine is blowing the air across the radiator theory symbolized by the white errors. I would blow their across the radiator. Cool the cooling water down we can see at the bottom here. We've got blue hours again. So we've called the cooling water down slightly. Other than that, the system is the same. So rather than using this pipe here, we're sending the flow the other way. And we're cool in the good and water down the thermostat. Bo is a proportional device will open and close a relative amount based upon the engine temperature. So if the engine is running very, very hot, the thermostat will be fully open. You can see their terms that expanded slightly because the engine temperature increased and now the flow is going the other way. Back that up again. See if we can get that. And again they go cold engine slowly becoming hotter now is hot on. The flow is going to go the opposite direction. This position, though off the thermostat as it is now. We'll see if I can get it somewhere in between. Okay. As it is now, we've got the same effect. We've got the bypass closed off, but it's important to realize that firmness that regulates it's gonna be opening and closing, moving up and down based upon the temperature engine. So sometimes it might not be fully open or fully closed willfully by Pastor should say sometimes it might be somewhere in between. And that's because the engine sometimes is no creating the maximum amount of he. Maybe it's just idling, and in that case you might want to send some cooling water to the radiator and some through the bypass. That's why they call it a thermostat because you're regulating the thermal temperature. This is also a feedback loop because the temperature of the engine is controlled by the thermostat on. Then the cooling water tells the thermostat with the engines injuries, then the firms that regulates the temperature again by deciding the flow direction off the cooler water it's ever looked Now at the thermostat in more detail. Okay, so here we are, looking out for him to stop a little spin so you can have a look at it. You can see on the top here. We've got a rod sticking out right here. This whole section on the top, the brass looking or copper looking piece is the primary valve around the primary valve A of a black piece, which is a piece of rubber like material used for sealing. The next black piece we have around here is also used for sealing. Actually, push this down into a recess within the engine on it, sit in there quite comfortably, and then you'll put the cover on. So it makes it quite easy to change the thermostat. I can also see there's an air bleed on if we go down to see a spring another spring. This section here is known as the secondary valve for the bypass valve, and perhaps the most important item is the charge cylinder, which is this or in space around here. So how does it work? We already know that if the temperature increases, then the top primary valve will open on the bypass valve will close, so we're not bypassing the radiator anymore. And if the temperature decreases, then the bypass opens on the primary valve to the radiator closes. So that's what it's doing. But how is it doing it? As you can see, it's quite a simple design. Well, the wait working is that there is wax within the charge Cylinder here on the wax is in a solid state below about 80 degrees Celsius. When the wax becomes hot, it turns to liquid on when it turns to liquid. It requires mawr volumetric space, or is of a large volume on that larger voya will push a rod out of the charge cylinder. Andi will actually close second to revolve or a bypass valve. So this right here from there to there, it actually goes up into the charge cylinder. When the charges becomes hot, wax melts becomes liquid. It's volume expands. It pushes the road downwards on that, then closes are bypass valve. So this secondary valve here is pushed down onto the seat on the radio. Bypasses closed. So that's what's happening when it's too hot. But at the same time, the primary valve one here will be opened. That means acumen, war, choosing goingto radiator where in the cooling water becomes cold again. The brought here will retract because the wax within the charge cylinder has a smaller volume and requires the space. So the Roger attracts upwards the bypass valve opens on. That means we're not saying including water to the radiator. As you can see, we are proportionately regulating the response off the thermostat in accordance with the engine cooling water temperature. Click here should be able to see the annotations again and then we go. So some annotations here engine thermostat. What it does the air bleed main valve from Revolve Sentara Secondary Valve, also called bypass valve so you could see all these past labeled. This is available on the website so encourages to go there and check out this three d model . The good and water system is also available on the website, so go and check it out and cement what you have learned. Let's go back to the Cold War system model now for the rest of the video. So hopefully now you understand how the cooling water system works. I just want to do a quick now here on thermal expansion and contraction. Thermal expansion is catered for by header tank. That's his thank you. As securing water system gets hot, some of it may expand if the temperatures becomes very hot on the cooling water will go into this pipe on will store the food and water in a header tank. So the Korean War header tank allows for thermal expansion of the system. If we don't have this tank than what's actually gonna happen is the good and water will expand. It will pass through a valve here, come out and just leave down the radio, sir, or through the pipe, and then lied down. So we have. They're headed. Thank there so we can store the food and water in the top. I miss allows for thermal expansion. The opposite of a very hot engine is a very cold engine, and we also have to take precautions against this as well. In order to protect the engine from freezing, we will add anti freeze into the cooling water system. The anti freeze prevents the water from freezing that, for example, minus five degrees Celsius. And it's very, very important that we do have the antifreeze in the engine. If we don't have the antifreeze in the engine, what will happen is the good and water will freeze minus five degrees. People expand on. We will rupture or crack our engine as well as potentially damage other engine components. So it's very important that the cooler water is not allowed to freeze on expand. In addition to having antifreeze in the engine, we're also gonna have a corrosion inhibitor on. This will help prevent rust accumulating within the engine cooling water system. Areas such as the jacketed cylinder, Lina, the pump thermostat and all these corrosion inhibitors stop rust accumulating there, which ultimately may file a heat exchanger on reduced the efficiency off the cooler water system. 25. Engine Lubrication: engine lubrication. An internal combustion engine would not run for even a few minutes if the moving parts were allowed to make metal to metal contact. The heat generated due to the tremendous amounts of friction would melt the metals, leading to the destruction of the engine. To prevent this, all moving parts ride on a thin film of oil that is pumped between all the moving parts of the engine. Once between the moving parts, the all serves two purposes. One. The oil lubricates the bearing surfaces to the oil cools the bearings by absorbing the friction generated heat. The flow of the altar moving parts is accomplished by the engines. Internal lubricating system Oil is accumulated and stored in the engines. Oil pan where one or more oil pumps takes a suction on pumps UAL through one or more oil filters. The filters. Clean your by removing any entrained metals within the oil general, where on the metal surfaces is a cause of these tiny metal particles or pieces in the oil. We cleaned all that flows up into the engines. Oil galleries, Pressure relief valve maintains all pressure in the galleries, returns all to the oil pan if the pressure is too high. Your galleries distribute the all total the bearing surfaces in the engine, so we're glad our engine or filter if we go down, we can see. In fact, we can actually read the rest of the lesson here. And then we look at a different parts. Once yours called and lubricate the bearing surfaces, it flows out the bearing due to gravity and back into the old pan medium to large diesel engines. Your is also called before being distributed into the block. This is accomplished by their an internal or external or kula lubrication. System also supplies oil to the engines governor discussed later in the course. So we've got here are engine or filter In the next lesson, Rex, you're gonna look at why we have an engine or filter on how it works. We need an oil filter to remove the sandy particles, accumulate in the engine or system, but we'll discuss that in greater detail in the associate video, or we have discussed that in creative detail. One thing we haven't looked at, though in the other videos is the shell and tube heat exchanger. Load up more love now remember the old system is there to lubricate Andi. Cool. Not just lubricate as most people think on. We will have a cooler because as it cools the engine down, it's going to absorb some of that heat. Remember, if you're cooling something down, then the thing that's doing the cooling is getting heated up, or vice versa. This is our shell and tube heat exchanger. I'm gonna explode out into all these parts. There we go, and we can compress it again back together. But these are all the parts. We've actually got three or four models of different shell and tube designs. This is one of our older ones. I'll show you how it works. Gone into our course on this. In case you're interested, the just assemble again. The fluid will flow in through the pipe on the left. Here will go away Long heat exchanger through those tubes we saw earlier, it's been back around and then come out the bottom and then on the other side will have a liquid or gas or whatever is coming in. Flows in here goes along here and goes out that way. And that is essentially how it works. But in order to work me open up, you will see that we've got choose here. The's tubes allow the liquid to flow within each of the troops. So that's Liquide, for example. Let's just say that is oil on. It flows into the tubes, and it's going to get to the end of the Jujubes. And then it's going to spin around because we got a you Ben type of shape. So every guy comes along here long, it spins around, goes back the other way on. Then he's gonna come out the lower half of the tubes on. Then it is going to be discharged. So let's have a look can see here, fellas. Just going. So I think we can. So, to see what's gonna happen, right or inside. So we've come in through the top hole, we can see the tubes there. The oil is gonna flow all the way down to the end, is going to go around the U bend that we looked at earlier. And then it's gonna come back out of these holes on, be discharged out of the bottom. So that's the oil. But as you might have noticed, there's a tight seal here. Where these panel is the reason we have that is because on the other side, off this plate is the water. So on the opposite side here, we've got water these flowing around the tubes but can't get out the end. So the water in the all not mixing on the water's gonna call down the oil. So that's what a shell into heat exchanger looks like. And that's how it works. But the water lend to here, and it will go longer. Serious baffles Overy z exact shape. We'll exit out of this hole here, whereas you comes down that way and spins around and goes back so the older water don't come into contact with each other directly. However, the heat from the or will be transferred to the water on, we will call down the oil. Almost all medium and large size engines are gonna have an oil cooler. It's not enough simply to cool the all in the or some, but what used to call the oil depends upon the system. If you've got an abundance of sea water, you might use that although the risk of contamination between saltwater and or is quite daunting. You don't want those two mixing if you got a hole in your oil pipe, for example. Last thing you want is a war going into the sea water, which is probably gonna be pumped overboard or into the ocean war, perhaps in worse seawater. Going into oil system depends on which system as the higher pressure. So you're gonna choose the cooling liquid or the cooling gas or whatever you're using depend on what's available. I would say they're generally sweet. War to a freshwater is quite suitable on these tubes that we saw earlier. These ones here, they may have, for example, double walls. Which means that the tubes are not just a single piece like this one here. There will be a tube within the tube. And that means if you get a leak on one of the tubes, you'll be able to detect that you have, like a leakage alarm on the leakage Allama golf, and then you can find out what the leaks coming from. But as you can imagine, you've got a tube within the tube. So the worst case that's gonna happen is the tube. One will leak into the other but you won't have any mixing between the oil on the water or the seawater in the all or whatever is flowing through there. So that's the shell and tube heat exchanger. We've got hit exchange course online, so check out if that interest you. And that's the type of heat exchange we're gonna use for our diesel engine or combustion engine. In orders, call the oil. There is a difference. I feed its danger, called a plate type heat exchanger, but you're less likely to use that for an internal combustion engine because it costs more generally on. It's not really required. It's a bit of overkill. A shelling tube heat exchangers. Fine. It works well. Proven on The big benefit is so it's cheap. 26. How Lubrication Oil Filters Work: in this video, we're going to look at an oil filter. Specifically, we're gonna look at the oil filter used on an internal combustion engine. I'm gonna explain to you how it works On day we're going to talk about why we have the oil filter in the first place. I could see an internal combustion engineer operating, and if we go down, we connect. You see on the side that we have an oil filter. Well, filter is this cylindrical object mounted onto the side of the engine on oil was flowing on our off the oil filter. Let's now look at a oil filter and I expect you how it works. So here is our oil filter. You can see it's been removed from the engine or has it been taken out of the packaging? On if we take a cross section, we can also see the internals. Now notice you spend this way again. This is a side that mounts onto the engine. This is actually a spin on type filter. It's a screw Fred in this section here on the screw through. It allows us to screw directly onto the engine and then tight in the field drop onto the engine. What happened then is the oil from the oil pump will be distributed through these outer holes. There is 12345678 of them on the oil will enter through those olds and into the filter. The oil outlets is actually the center hole, this hole in the middle. So let's have a look also at the rink. Because as we screw into the engine, obviously we don't want metal. Just seeking on metal, cause will get oil leaks on orders. Get around. This problem we have in a ring your room is this black piece around the outside on That would be a piece off rubber or some sort of elastomers so that we can really squeeze that against the engine and get a good seal. So stop our oil filter from leaking, but the outer casing of the oil filter it's going to be metal. A cross section. Now go in. I can see that the always gonna coming through the whole Ryan side on it's gonna meet. This black piece assumes enters the filter. This is actually an anti drain valve. You can think of it as being similar to a non return valve. Your pressure is gonna push against the anti drain valve. This black rubber type flexible material on the all these guns caused the black robe piece to extend out to about here. So it's gonna move across this way and you will be allowed to flowing to the oil filter. So it started number two valve What? They call it an anti drain valve. He had to drain. Valve actually stops you all from exit in the filter when the oil pump is switched off. So in other words, if we shut down the engine, the tendency is that the oil due to gravity is going toe all accumulate annual sum at the bottom of the engine. However, with the anti drain valve, what we can actually do is seal the oil in the filter on. That means that the oil filter is gonna be charged or full of oil. That means when we start the engine, we're gonna have a supply of oil already. If we was a drain, your filter down and we risk starving the engine of oil. We may run the engine without any lubrication or where we initially started on This is not good. We're going to get a lot of wear on the components. So that's the reason we have the drain valve and you will come in your flow around this way and then it's gonna come into contact without paper, please. These are these orangey brown paper on the oil is going to flow through the pleats and into the middle. Can you see her? Each one of these pleats is shaped a little bit like a flower on the interior is hollow And that's because we all comes along and it was correctly it's gonna come in here and it's gonna pass through the paper and then down this way uh, possibly paper again. Andi, Into this central pipe here. Inflows of holes. Holes over there. Teoh, help the oil drain back into the center. So it's fast, Really. Paper bleats on now they all could be referred to clean because 20 past three leas pleads. What actually happened was that the impurities and the foreign bodies which might be dust, dirt, rust, anything like that they will become in trained upon the pleats. On there. We effectively stopping me outside the or will pass through, but the impurities or the foreign bodies will know. So that's how we clean the oil. Once the old been cleaned passenger to central pipe, I will goto oil galleries on. Then it will be distributed to the components of the engine. So that's what your filter is doing. It's keeping the oil clean, so now we know how it works. Let's think why we would have an oil filter in the first place. Well, the main reason is to remove the foreign bodies and impurities on This stops erosion off engine components occurring. That's a matter for a moment that we did not remove these particles and these usually higher particles. They feel very sandy when you rub them between your fingers and fun. Now, if we didn't remove these sandy particles, these foreign bodies, then they're gonna go straight Teoh bearings and other machinery components, as these components usually operate on very fine tolerances. Remember, a plane bearing has an oil film on these bearings are also called thin feel bearings the river into the very thin layer of oil that separates the bearing from the pieces. It's sandwich between. So let's imagine that the bearing is sitting between the crankshaft and the Konrad. Well, if we get a part school flowing through the old system on it, then flows on goes between our bearing, then we're going to scratch the piece of metal away from the bearing. Now this scratching motions called erosion on the most likely piece, it's gonna become eroded. He's actually the bearing itself plain bearings of manufactured from a soft material. This is a material referred to his white metal or Babbitt metal, and it's very soft. So our sandy particles, if they get in there, they're going to scratch away bearing on. Then we might end up with hearing hot spots, or we might just end up with a thinner bearing over. Time on. This might cause lubrication issues, so there's a lot of things that could occur if we start eroding away. Some of the engine components to the old system is absolutely critical to union. It cools engine. Andi lubricates the engine. If we start in a very dirty little system, then we're going to start getting a lot of problems. So that's why we have the oil filter. It's very simple, but you will need to change it periodically as it becomes dirty. But if you check in your engine manual, you'll soon discover that there are several ways when you will know to change in oil. Filter first ways using a measurement of distance, such as kilometers or miles, you may see in the manually says, after the 1st 5000 miles or 5000 kilometers or whatever the number, maybe the next way is based upon service hours. For example, after the 1st 2000 operational hours, in other words, 2000 hours when the engine was running or, for example, after 4000 hours, 8000 hours, etcetera. And finally, if none of those are relevant, then there will be a note in the manual saying that the filter should be changed every 12 months as a minimum, so they're free different ways they're of known when dual filter should be changed. If you're working on larger engine, you can just measure the differential pressure across the oil filter on. When the different your pressure becomes too great, you'll know that it's time to change. Your filter were warning. If you change the filter too late, you may effectively start the engine of oil because you're cannot pass through the filter quick enough to get to the engine components on what your notice is. Other that the engine will become quite hot and your lubrication oil temperature will also become quite hot. And you may also find that next time change the filter. There are a lot more particles in there than there should be, and this is because the engine was damaged as it was starved of oil. Didn't have enough duplication, so you've no only had hot oil in the engine, but you've also damaged engine due to lack of lubrication. Heroes are mentioned as well that if there's a lack of oil, you also gonna lack cooling. You may also end up thermally damaging the engine so oil very, very important. And it's important that you keep your oil filter maintained in order that your entire oil system remains healthy and that your engine remains healthy 27. Fuel System: fuel system. All these legends require a method store and deliver fuel to the engine. Fuel is stored remotely from the engine on a circulation pump is used to deliver a return fuel to or from the engine. So we got a fuel tank on. The fuel is gonna be sucked out of the tank by a pump. We can see the pump here. So this is the tank. There is Pump well, suck fuel out will discharge the fuel to the engine specifically to fuel injectors on. Then we will circulate some of that fuel back to the tank again. So, Noel, the fuel is going to the injectors where he's going to the injectors. But not all of it is being used by the injectors will explain why in a moment, because thes legends rely on fuel injectors, which of precision components with extremely tight tolerances on various small injection holes. The fuel delivered to the engine must be extremely clean and free of contaminants. So here we got a common rail fuel injector with a fuel connection on the top on Elektronik connection on on the side for the electromagnetic valve on. Then there'll be a hydraulic connection at the back on, we can load up this model in a moment. The fuel system must therefore not only deliver the fuel but also ensure its cleanliness. This is usually accomplished for a series of in line filters. Commonly, the fuel will be filtered once outside the engine and then the fuel passed through at least one more filter internal to the engine, usually located in the fuel line in each fuel injector. The fuel injector actually has little holes at the bottom of the nozzle end on these holes are very, very fine on. In order to ensure that you don't block these holes which allow the fuel into the combustion space, you need to make sure the fuel is very, very clean. So in order to do that, you're gonna have a big filter like this, or a filter mounted onto zai engine, which usually just on screw on clamp on. Then you'll have another fuel filter which is gonna be almost located on the injector or next to the injector on that one is an extremely fine filter. So you're picking out all of the impurities if there are any on the reason you install the filter directly on the injector or very close to it is because you want to catch any bits of rust that might have been in the piping between the fuel filter on the outside. So this big one on the injector itself, So remember you got piping from this fuel filled, so that's gonna go all the way to your injectors. Andi, maybe for a fuel pump or a prime in pump, etcetera. Andi. If there's a bit of rust that drops off the pipe, or if there's a bit of but the no contamination or anything like that, that's after the fuel filter. Then you're gonna need another fuel filter to pick that up on do to stop it going through the injector. So that's where you have to separate fuel filters in a diesel engine. The fuel system is much more complex than the fuel system on a simple gasoline engine. Because the fuel serves two purposes. One purpose is to supply the fuel to run the engine. The other is tractors, a cool into the injectors. To meet this second purpose, diesel fuel has kept continuously flowing through the engines. Fuel system at a flow rate much higher than required. Simply run the engine. The excess fuel is routed back to the fuel pump or the fuel stories tank, depending upon the application, so tip one fuel passes through. The injecting also holds and is vaporised into tiny droplets as it enters a combustion chamber. Vaporised fuel forms an ideal fuel to air mix and yields a much faster and more efficient means of combustion. Tip to the fuel filter should be changed periodically, as it will tend to become blocked or clogged over time. A brought fuel filter will cause a flow restriction in the fuel line on May lead to the engine being staffed. A few consult your engine maintenance manual to find the correct maintenance interval, which is usually given in months. Engine operational hours or kilometers or miles Distance So it it won. The fuel is vaporised. Keep that in mind. That's where the fuel passes through the injector. And as it gets into the combustion space, we're going to vaporize that fuel. It's gonna become almost like an atomized mist on. That gives us a very large contact surface area with the air or the hot gases in the combustion space and that means the fuel is gonna ignite very, very quickly. Interestingly, when the fuel actually turned to this misty vapor, you get a pressure drop and you actually get a temperature drop. This only lasts a very short short period of time. It's just quite interesting when you think about it, because you think it goes into the hot combustion space. But as it is first vaporised, you will get a pressure drop, which ultimately leads to a temperature drop. And then afterwards it will combust, as I say that that's all happening very, very quickly. Tip to the fuel filter should be changed periodically. This is true. The wand it's on the injectors or close to it should be checked periodically. It's not gonna be very dirty, or it's highly unlikely, but this one should definitely be changed periodically. If you have a fuel filter that's just been left on for a long period of time, and no one's ever looked at it, you're eventually starve the engine of fuel, which means you need to know only change the fuel filter, but you need to bleed the engine and you need to bleed the engine or the fuel system from the injectors. So what you'll do is your loosen awful. The pipe in that the injectors. You'll turn the engine over on. Then you'll try and pump fuel through to the injectors and you try and get the air out where you've opened up the piping on each injector. Now, this can be quiet. Dawson on. When you start the engine again, you're going to get very regular engine that is operating is gonna make very weird noise Rather than get a constant broom noise like Brewer a river, it doesn't sound like that already. Sounds a bit more like pepper. Andi, etcetera. Sorry if my sound effects are very good, but I literally what it sounds like. But it's not the end of the world if you have to bleed the injectors or bleed the air from the injectors. Is a little bit of a problem, though. When you really need to diesel engine and you're standing there trying to believe the injectors. It's even worse if you don't have the correct tools with you and then you are standing there with no diesel engine and no tools to fix it. I will say I've had it in the past, where is in a small watercraft called a tender? It was only about 20 foot long, so quite small, and we re literally bobbing around in the ocean without a diesel engine, and we had no tools to fix it, so this was quite frustrating. I think in the end, we actually just took a Leatherman. I managed to loosen awful the connections and bleed the engine. But it's not an ideal situation. And if you consider many diesel engines or use of things like emergency generators, then obviously you want that diesel engine to be working in an emergency. If it's not because someone hasn't changed a fuel filter than that is really no ideal. So let's now load up the fuel injector. I could load up the tank model, but it's essentially a tank with a suction line inside. And that's more for an automotive course that we've got coming up soon. The fuel filter works very similar to a lubrication oil filter, which we saw earlier, so I don't think we need to look that one up. What will load up the fuel injector, though, because the fuel injector itself is quite an interesting piece. So here's our fuel injector. Well, dio I'll explode out into all these parts are not going to go through every single part. Fuel injector you can see already is quite a complicated bit of kit have taken these apart on large container ships before. But I don't remember them being this sort of finicky and having so many small parts. It was for a very large to strike engine. Normally, for very large engines, you can take the injectors apart, and you can check the spray pattern is the pattern that comes out of the spray nozzle, which is this end here can see there's a doctor here. I don't there. So that's where the fuel Oops, sorry, it's back up moment. That's where the fuel comes out of the spray nozzle on. It will be vaporised or atomized as it comes out. And like I say, you check the spray pattern. You'll check. The nozzle is clean and reports of free. I haven't done much work on smaller fuel injectors over than to take a brass wire brush and clean up the ends. Andi. Maybe then bring store new fuel injectors and send the old ones away from maintenance, so have not taken one. Such as It's a part. However, I can tell you the working concept we can see here we've got on electrical connection. That's for our electromagnetic valve for a solenoid valve, common rail fuel injector. That is the design we're looking at. We've got a hydraulic connection here. That's the hydraulic fluid used to open and close. The fuel injector got Siris of springs, which will return the fuel injected to a closed position ons. Then further down, we've got a shaft where the fuel would come in. That goes away through to our spray nozzle can see the housing here. The fuel comes in through this section here, Andi. Then we've got our area where it screws onto the piece. And, as I say, a fuel injector or sorry, the nozzle Is this please here or the lower pointy piece? It's Just assemble it for a moment when we can see again. So hydraulic connection, electrical connection, fuel connection, that one year on the fuel then goes into the injector and will inject when the electromagnetic valve moves to the open position. So, Vince, have a look. We could see again the spray nozzles here. So that's where the fuel ultimately comes out. One another one to spin around three and four etcetera. Usually they'll actually be one of the tip here as well. When analyses right now. So what's gonna happen? Is that still a quick run down or a quick recap here? We know it's common rail because we saw the electrical connection. So when we want to inject fuel, we will send electrical current through the connection here, that electrical current or the flowing electrons ago New open the electromagnetic valve. They're going to do this because they create an electromagnetic field that pull a plunger upwards or to the right. In this case, as they pull the plunger to the right, that's gonna open the electromagnetic valve, which is a song. My valve. It's gonna open the soul. Annoyed. We're gonna let hydraulic fluid into the injector that's gonna open up another valve on now . The other valves are opened up is gonna allow fuel to go to the combustion space once we remove the flow of electrons. In other words, once we take away the electrical signal springs, they're gonna close the hydraulic valve on then because there's no hydraulic fluid in the hydraulic pressure. We're going to close the fuel valve as well to the injector. On that point, we stop injecting fuel. The good thing about common rail system, where whenever we used in solemn vows, is that we can very precisely controlled the time and the duration of injection on we can adjust it as needed. That's not so easy to do with a camshaft. So that's a big benefit we can control, not just when fuel is injected, but for how long. Let's take a cross section, and we can see some of the parts there as well, and you'll see that the fuel comes down this way along here on all the way to the injector nozzle. Conceive a series of springs as well, such as this section here. Andi again is another spring year on another spring here, and we'll see a section for the hydraulic system as well, which is gonna be the sole section here, the electromagnetic valve, Or just see if I can locate piece would be approximately if I had a guess. Here it's gonna be somewhere and around this top section, and there will be a plunger big normally a shaft here with a series of calls around it. Conceive everyone on this example, but a solenoid is just essentially a copper coil with a piece of line in the middle on. When you apply a current, the copper coil creates an electromagnetic field on. This will pull the piece of iron in the middle in one direction and then use the spring to reset it back in the other direction. So that's our solid with housework, and that is essentially our fuel injector will use that to the inject the fuel directly into the combustion space. I'll just make it like that again, because from this view, this is how you enormous see the injector and you'll see it screwed into the top of the cylinder head. Andi taking these injectors out. Replacing them and sending the old ones away for repair is a typical job you do as part of a scheduled maintenance plan. If you consult your owner's manual, you will actually find out exactly when you need to do that, and you can check the inject his condition by checking our dirty. The liar end is that goes into the combustion space on also how dirty the tips are here. If all of your injector holes in the nozzle blocked, then this is not a good sign. You have a very high buildup of carbon, and this is not good because it means you're spray pattern was not there. So you get in a very inefficient burning of fuel. So we need to make sure that this whole area here is clean. If there's a huge buildup of carbon than you really want to check, what the reason for that is, it might be a very dirty fuel, but it's still worth checking. So that's a fuel injector. Let's move on now with the next lesson. 28. Charging and Scavenging: charging and scavenging. The process of admitting air into the combustion space is known as charging the process. Admitting air and expelling exhaust gas is known. A scavenging the three main types of scavenging for to strike engines are cross flow union flow and loot flow. Notice on the image below that the cross flow and loot flow scavenging types used ports only whilst the union flow type uses vows for exhausts and ports for inlet. Note that most diesel engines typically do not use only unit flow. Scavenging union flow is only for very large marine engines. So these there are scavenging types, just member charging the process of getting air into the cylinder, scavenging the process of getting air into the combustion space or into the cylinder. Andi. Removing exhaust gas so that's essentially charging is charging is the one psychic, and Aaron Scavenging is getting the Aaron and the exhaust gas l. We could see how three designs that we looked at earlier cross flow because it flows across the combustion space union flow because it's flown uniformly from the lower end up to the top on loot flow because as a loop pattern, so these air for two stroke engines were also got on the left petrol engine as a spark plug on the right are petrol engine as a spark plug on in the middle. We've got fuel injectors, so that's a diesel engine. Tip one. The terms turbocharger and supercharger referred to the process of forcing more air into the combustion space, which is effectively super or turbocharging. So it's a bit of a play on words. We know already that charging is put in the air into the cylinder so women turbocharging or supercharging you'll know. That's why we call it charging in the first place. Otherwise, it would just be called a turbot did to What's the difference? Doing a supercharger on a turbocharger? Well, rather than just released, you'll actually just tell you a supercharger is driven in some manner from the crankshaft. So it's taking load or is taking energy away from the main engine because it's effectively requiring the engine in order for it to operate, it's gonna be driven by gears or a chain or similar. Where is a turbocharger is driven by exhaust gas? That's what makes it operate. So a turbocharger is a lot more efficient because it's used in a waste product such as exhaust gas to make it operate, whereas a supercharger uses the engine. So I think about it. The exhaust gas was going out of the engine anyway, so if we can get it to do some useful work, great on what we're gonna do, we'll get it to rotate the turbocharger or to operate the turbocharger. And that means we're getting mawr work out compared to if exhaust gas just was delivered or discharge to atmosphere. So the turbo charge of winds on the efficiency scale, however, a supercharger could be driven directly from the engine on there is no delay. What they refer to his turbo like double act does not exist with a supercharger because it's directly coupled and condemn directly respond to the changing engine speed. This is not true that it's over a charge it because it takes a while for more exhaust gas to flow to the turbocharger. And that's why we have something called turbo lag. We're going to discuss all of these concepts ovary soon at overcharge a video so don't stress too much tip free load on the engine or sometimes referred to his parasitic loads because they draw upon the power the engine creates on. This power cannot be delivered to the main drive de gea cooling water pump. Alternator and supercharger are all examples of parasitic loads, so a parasitic load is like a parasite. The parasite is similar to a tick or leech or anything like that that sucks energy from its host or blood on. These parasitic loads are effectively taken away, energy or power that could have been delivered to the main drive. So it's quite important that you reduce him out. Parasitic loads as much as possible On alternator, for example, is a parasitic load because is engaged with the main engine or the main drive, and it's gonna be constantly charging the battery. The air conditioning in a car also requires a compressor, so that's another parasitic load and quite a big one. Anyway. Let's see if there's a model we can load. Fact, it doesn't look like it. We had a look at this earlier thes scavenging methods to keep in mind just for this lesson , charging the process of getting air into the cylinder scavenging the process of getting Aaron on exhaust gas helped 29. Air Intake System: Aaron take system because the diesel engine requires close tolerances to achieve its compression ratio. Because most diesel engines are either turbocharged or supercharged, the air entering the engine must be clean, free of debris and as cool as possible, Ideally cooled to just above the Air Dew Point, The air intake system is designed to clean, compress and cool the air prior to entering the combustion space. So important factors here clean, which you'll be doing with filter compress, which will be doing with the turbocharger or supercharger and cool, which you'll be doing after the turbocharger or supercharger. The reason you call the air down is simply because a cooler mass of air or Akula volume of air, so to say, means that the mass is greater, and that means you can get more air into the combustion space, so we compress it. So we get a great and massive air going into the combustion space, and then we cool it so we can also increase the massive air going into the combustion space again. We have to be careful that we don't over cool it can see, says here, just above the a Jew point. If you over. Call it. You're going to get water molecules that accumulate within the air or they condense on. If they go into or if they are compressed in the combustion space and then they become water molecules, then you're gonna end up with something very similar to acid rain. It's what happens. You'll have the water in the combustion space is gonna mix with sulphur on. Then you're gonna have acid rain. And then it's going to start eating away your cylinder, Lina on perhaps your other parts, such as you pissed the rings and maybe the piston. So all in all, not good. Make sure you don't get any moisture. What, so ever going into your combust in space? The only place where it's gonna go in typically is if you over cool the in going charger. That is an air intake system, which will see a not so very charge of video wet and dry cleaning. Erin take systems very greatly from vendor to vendor, but usually one of two types wet or dry. In a wet filter intake system, the air is sucked or bubble for a housing that holds a bath of oil, such that the dirt in the air is removed by the all in the filter the ebb and flows through a screen type material to ensure any in trained, all is removed from the air in a dry filter system, paper, cloth or a metal screen. Material is used to catch and trapped ER before enters the engine similar to the type used in automobile engines. In my experience, the predominant one or the one you're most likely to see is a dry filter. It's essentially just a piece of fabric, usually has a metal mesh on the inside, and they'll attach the fabric to it and you'll suck the air through the fabric. And over time the fabric will become quite dirty and in your meats change the air filter, the wet type. I don't think I've ever worked with this before, quite surprising, because I thought I had worked on a fair. Few engines, however, just goes to show there's always something new to learn on the bath of oil, such that the dirt in the air is moved by the all in the filter. So since she we are drawing air through a bath of oil or bubbling it through oil and that is going to clean the air because the molecules going to stick to the oil on the air is going to continue traveling through the or so there's a way of separating the foreign particles there from the Airstream. So we're getting clean air going toe our engine location of Air Inlet. In addition to clean in the air, the intake system is usually designed to intake. Fresh air from a far away from the engine is practicable, usually just outside the engines. Build nor enclosure. This provides the engine with the supply of there. There's not being reheated or heated by the engines. Own waste heat. This is fairly obvious. I think you're not going to suck the air from a location that is almost next to the exhaust gas manifold or the exhaust gas outlet, because if you do that, you're gonna be sucking in some of the exhaust gas as well. Ideally, you want to suck in air that has not been heated up by the engine. Andi. That is fresh. In other words, it contains a relative or normal amount of oxygen. Reason cool in the air. The reason for ensuring that and engines Air supplies as cool as possible is that cool air is more dense and hot air. This means that per unit volume cool air has more oxygen. The hot air. Thus cool air provides more oxygen Percentages charge less dense hot air. More oxygen means amore efficient fuel burn on more power. If we want more power from diesel engine, we can't just increase in that fuel going into the combustion space. That's not going to do anything. We can increase it, but we have to increase. The amount of oxygen has to be a proportional or ratio between the air. Andi, the fuel or the oxygen, the fuel. So again, think of that fire triangle. We need oxygen. We need fuel and we need heat. We've got heat and then we need to add more fuel. So we need to add more oxygen. If we don't do that, we're not going to get an efficient burn. And it's gonna be other black smoke that comes out of the exhaust or it's gonna be white smoke that comes out the exhaust, which we discussed earlier on as being either too much or too little fuel, respectively, distribution to the combustion space after being filtered. The air is rooted body intake system into the engines, intake manifold or air box. The manifold, or air box, is a component directs the fresh air to each of the engines, intake valves or ports. If the engine is turbocharged to supercharge, the fresh air will be compressed with a blower and possibly cool before entering the intake manifold or air box. The intake system also serves to reduce the airflow noise. The one year manifold manifold is the posh words when you connect those two small pipes onto a bigger pipe, such as we got here on before we load up that model, just double a copy and make sure missed anything out. My clean the air, compressing air. Cool the air where or dry filter. Typically you'll be seen. The dry type is very easy to install. Andi change, which is good because they have to be changed quite often. Location of the Air Inlet. This is obvious. Make sure it's away from the exhausts. Make sure it's not picking up. Hot air or air has been heated by the engine. We call the air because we want to increase the mass of oxygen that goes into the combustion space on distribution to the combustion space has done for this intake manifold . So let's load this model up. It's pretty basic, so we've got intake manifold. We've got four pipes that connect to the cylinders, and they connect to one main manifold. We have a manifold because actually reduces the pressure. Pulsations that go to the cylinders themselves will go to the combustion space. If we had one connection, it's just imagine for a moment that we had this one connection here and it went straight to the ambient air or to atmosphere, or imagine went to a turbocharger. It had its own turbocharger. Then every time we open the intake valves, we're going to get a huge pressure drop on that compressed air or fresh air is gonna force its way into the cylinder. However, when we have an entire manifold, that's for with charged there, then these pressure fluctuations are gonna be far less on effectively. Were dampening the pressure fluctuations because we've got loads of air stored in the manifold here on that air could be drawn upon from these four cylinders, usually at different times. So, you know opening all the once and draining all the air out the manifold. You're opening a little bit at once because there's a large volume of ear in the manifold space. You can deal with the valves or these pressure fluctuations every time the valves open. So that's a good reason to have an entire manifold full of charged air on other engines. You'll see that there is one connection to the cylinder on there'll be one pipe that goes to a turbocharger or supercharger, or perhaps to atmosphere. But the problem with that set up is a soon as the inlet valves open, you get a huge pressure drop in the air line or in the charge airline, whereas with this set up here were you drawn from the manifold. You don't get such a massive pressure drop because you've got a large volume of air to drawn in the manifold, not the case when you don't have a manifold. So anyway, it's two separate setups you might see. Let's do a little spin here, conceive what? Attach a gasket on. To this end, we attach gaskets also long here, or one main gasket on that would connect on Teoh cylinder on. That is effectively how we get air, then into the combustion space. All of our models seem to have made of stainless steel, which is bizarre because a lot of these PC would normally be made out of cast iron or something that's not very expensive. However, for our purposes, you can see it's a very nice stainless steel inlet. 30. Turbocharging: turbocharging, turbocharging and engine occurs when the engines own exhaust gases are forced through a turbine, which rotates and is connected on a common shaft to an impeller, or centrifugal compressor, which is located in the fresh air intake system. The impeller in the fresh air intake system compresses the fresh air so he would conceive. This is actually our turbocharge a turbine. The exhaust gas passes over a turbine connected on a common shaft to a compressor on its this compressor that effectively compresses air in coming here. Don't get too worried. We're going to deal with this in the next lesson. Enough said that a lot in this course, but finally, the turbocharger lesson. He's coming, so don't stress the compressed air. Serves two functions. One. It increases the engines available power by increasing the maximum amount of air or oxygen that is forced into each cylinder. This allows more fuel to be burn efficiently because we have the correct air to fuel ratio , and this means that more power can be produced by the engine to to the second function is to increasing. Take pressure increasingly and take pressure improves to scavenge in for the removal of the exhaust gases out of the cylinder. Togo charging is commonly found on high, powerful strike engines. It can also be found on two stroke engines, where the increasing intake pressure generated by the turbocharger is required to force the fresh air charge into the cylinder and helped force the exhaust gases out of the cylinder to enable the engine to run. So let's go to our main points 0.1. It increases engines available power by increasing the amount of air or oxygen that's forced into each cylinder. If we compress the air, that means we get in a greater mass off air oxygen into the cylinder. And that means we can add more fuel and burn the fuel efficiently. And that gives us more power. Tip two or item to the second function is to increase the intake pressure. If the intake air or the charge air has a high pressure, that means that when it is allowed into the combustion space, it's gonna flow in a lot more quickly or easier than if it has a low pressure. Let's imagine for a moment the pressure in the combustion space just, for example, was one bar. In fact, will say less. Well, say it. Zero. So let's say zero bar. If we've got 00.1 of a bar in the Air Inlet manifold, then the mouth here it's gonna move into the combustion space is quite low because we've only got a difference of 0.1 bar. However, if we've got 0.5 bar, then the amount of air that flows into the combustion space when it's allowed to flow in he's gonna be far greater because the difference between the combustion space pressure on the Air Inlet pressure is 0.5 bar, Remember, Combustion spaces. Zero bar on the air inlet is 0.5 bar. So the difference is 0.5, which means we're gonna get more air that moves from the Air Inlet into the combustion space, and it's the same with the wind as well. Think about it when you've got a large pressure difference, then you're gonna have a high wind speed. If you got a low pressure difference, then you're gonna have a low wind speed. So if you think about it like that, that makes sense. You want a high pressure difference within reason as high as possible. On this is gonna force more Aaron more quickly, and it's going to allow you to get rid of that exhaust gas as quickly as possible. So that is the second function off the turbocharger without further ado. Now, I think Let's get on and have a look. At what? The turbocharge Aries. And after that, we can have a look at a supercharger or at least very pretty. If you're gonna talk about it, he enjoy. 31. How Turbochargers Work: in this video, we're going to look at a turbocharger. We're gonna look at all of the turbo charges, main components. We're gonna look at how it functions. Then we'll look at why you would have a turbocharger installed on. We'll discuss concepts such as turbo lag. So here we have a four stroke the six engine on on the back off the six cylinder engine. We have a turbocharger. This is the turbocharger can see it in the center of the screen. Now the turbocharger looks slightly like a snail review from the other side. So the reason I'm showing you this is because if you ever see a turbocharger or if you look in an engine, you'll be able to identify it. You'll also be able to identify it because it's connected to two separate systems, the air system on the exhaust system. So let's now have a look at the turbocharger and all of its components, and then we'll discuss how it works. So again, here is a more detailed model off a very charger. See the different sides, and now you can also see some of the interior components season the outer casing on the opposite side as well. So let's break this down into his components on DWI can then have a look at how it functions. They got exploded. The model at this end, this is the end that connects to the air. Sister, this is what's called a veloute casing will often see the same shape on centrifugal pumps. And this is snail light shape. Here, we can see that the inlet is through the center of Samos. Four centrifugal pumps on a discharge. He's out of this pipe. Here. Go Outlet here on requiring. Let on. This connects to the air system within. Go a compressor wheel. That's this item here and then Pastor, we gotta plates on further down. We've got what they call a central hub. Rotating assembly. Looks like a couple of bearings here. A shaft shaft coming all the way through. Besides, in here is a turbine. Then we got the casing again. Let's just assemble that again and we'll talk about the systems that it's connected to. So on the left hand side, as previously mentioned, this side here connects to the air system. This is drawing air into the engine. We're gonna use that air for combustion because it contains oxygen. Go on the other side. We've got a turbine. This is a gas turbine and what we're gonna do, we're gonna pass exhaust gas over the turbine on. We are going to cause turbine to rotate on. This turbine is connected on a common shaft to the compressor. So turbine on the exhaust gas side of the engine, but his exhaust gas coming from the engine here and going to the turbine go on the opposite side got compressed. They're going to a compressor on that. He's connected on a common shaft to the turbine. So, as you might have realized, if the main driver for the turbocharger is the turbine, which it is, then as the turbine turns, it's also gonna turn the compressor. That's important to realize this because as the turbine turns or increases with decreasing speed, it's gonna turn to compress a wheel because it's on a common shaft. Keep that in mind. What I'm gonna do now, it's switched to another model, and I'm gonna tell you exactly what the turbocharger does. So here we are. This is a turbocharger on. This is a system where it will be installed we saw where it was on the engine earlier. But now what you're actually seeing is just the air system on the exhaust gas system you can see. In fact, let's just start by the turbocharger. We have a turbocharger, although it's slightly rusty, and then we can see this imply thing we haven't after Cooler on. Then we have a combustion chamber on a piston. We can see also some red and blue arrows. The red arrows symbolize the exhaust gas. So we can see. Here is some red arrows. The blue arrows symbolize compressed air. So let's walk through the system now, and it's going to exactly how the whole thing works. So our engine is running on. We've got some exhaust gas coming out and going into the turbocharger on the exhaust gas side. So fat, let's go to our cylinder access where the exhaust gas would come from. So you're the guy. The exhaust gas is coming out here. And if these vows were open, we got to yourselves Aires one to these two drawers, fouls to compress their valves. These air air inlet valves on the left source. Gas on the right. When these open the exhaust gas is going to pass out off the cylinder or the combustion space, and then it's gonna go. Just do my here along this Bible along here, along here, along here on it's gonna go to a turbocharger. So the exhaust gas guns a turbocharger as it passes over the exhaust guests turbine. It's gonna cause this turbine to rotate. Now the turbine is connected on the common shaft to the compressor wheel. So now the exhaust gas is gonna leave the engine. It's done. It's work on. We're gonna have a look at what happens to the compressor wheel. Remember, it's connected on the common chef over. Go See Central Bob Rotating assembly. Here is the compressor that is now also turning because exhaust gases coming out off the engine and passing over the turbine. So is turning its drawing it in, and this air is then going to be compressed. That's what we call it. Compresses will. It's going to compress the air, we compress the air and then we'll discharge it to the veloute casing. This casing is actually designed so that the velocity will drop on. The pressure will increase. That's what I've glued casing does. So the air velocity is going to drop. The pressure's gonna increase on. Then it's gonna be discharged along this pipe along a long here. We're going to cool the air down. I'll tell you the reason for that in a moment gonna Coolio down in the after Kula on. Then we're gonna go along here, along here on into our cylinder again or into a combustion space should call it a cylinder liner rather than just still end up. But I think you understand me that's gonna come in then through these two valves when they open. So now we know what it's doing. Let's discuss why it's doing what it's doing. Well, the exhaust gas is just a waste product, so any energy that we can get from the exhaust gas before we discharge it to atmosphere would be a buyer nous Now with diesel engine, you can actually get more power from the engine if you compress the air and get more oxygen into the combustion space. If we can have more oxygen to the combustion space, then we can add more fuel. If we had more fuel than we can create more power or At least we can transfer more power to our load. Now load. Maybe an emergency generator, maybe a truck. It may be a pump. It doesn't matter. But if we have more fuel, then we need to add more oxygen. The turbo charger allows us to add more oxygen in the same volumetric space. So let's have a look at the combustion space you can see here. But the space is limited. We're only ever gonna be able to work within the confines off the combustion space. So that's gonna be a maximum where the piston moves down the bottom dead center all the way up until the top off the cylinder liner. So if you want to create more power, then we could just put more fueling. The problem is, we don't have enough oxygen. In order to get efficient combustion, you need to have all the elements of a fire triangle. That means oxygen heats on fuel. Now the oxygen is supplied from the ambient air. The fuel is delivered from a fuel system on our fuel injector, which we can see at the top. Yeah, and the heat is supplied as the piston moves up the cylinder Lina and compresses the gas were, in this case, the air. So we've got heat because you get in that when we compress the air within the combustion space, we got a few, but we need the oxygen. So if you want to increase the power, we've gotta deal with all of these elements of the fire triangle. Now we know that we can just add more fuel. That's not a big deal. We can't really add more heat, but there is enough heat there because we're compressing over the air within the combustion space. How we gonna get more oxygen into the combustion space in order that we can generate more power? That's where the turbocharger comes in. The exhaust gas draws the turbine and that drives the compressor. Will, as we compress the air, were also increasing the amount of oxygen that is packed into the combustion space. In other words, we're increasing The density is gonna be more oxygen within the combustion space. But we can go even further, not only with we compressed the air in order that we can get more oxygen into the combustion space, you can see we're also cooling the air so Here's our after cooler, maybe cooling that with depend on size engine with air or born auxiliary system. That's the air comes in. It's gonna be cooled down in the after Kula on the temperature is going to drop. So why would we drop the temperature off the compressed air? Well, the idea is exactly the same as before. If we call the air, it becomes more dense and again we get more oxygen into the combustion space so we compress the air to increase the oxygen content and then we cool it down again because during compression in the turbo charge of the air will become quite hot. So we call it down and again really increase the amount of oxygen we can put into the combustion space. They were compressed it, we've called it, and then it's delivered into the combustion space because we've got more oxygen, we can then deliver more fuel. And when we burn more fuel, we're going to create more exhaust gas on when we create war exhaust gas. Then the turbocharger turbine is gonna turn even faster. The turbo charge of turbine turns faster than we can compress more air If we compress more air than we can add more fuel, etcetera, etcetera. So this is a feedback loop. We are adding more air, which allows us to burn more fuel, which creates more exhaust gas, which allows us to compress more air. This allows us then to inject more fuel, which gives us more resource gas, which makes a turbocharger terrible and going faster, which allows us to compress more air. So it's a feedback loop, and by now you might be wondering what happens when we start the engine. But when you initially start the engine, the compressor wheel is turning so slowly it is almost non effective, and when you had more fuel, you'll only slowly increase the amount of exhaust gas. Going to the turbine takes a moment for the turbine to really get going once it has the additional exhaust gas. Because of this delay, from when you put your foot down, up until the point where the turbine starts turning and you compress more air and get more power, this is actually referred to his turbo lag. That's where you have turbo lag. When you think about it, it makes sense putting your foot down on the accelerator is not going to give you more power. What you need is more fuel on more oxygen, not just more fuel. So in a nutshell, turbo lack equals a delay in response to desired acceleration. In other words, you put your foot down on the accelerator and the response you want is no immediate. And that's what we referred to his turbo lag. So now you know what turbo lag he's. Hopefully that's relatively clear. It's up to talk now about some of the advances. Use off a turbocharger the advantages with the turbocharger that there is increased efficiency. Thermal efficiency increases by up to 15%. So we haven't increased overall engine efficiency. We also increased the power output of the engine, and this gives us a higher power to weight ratio. So you have to imagine you would probably add in less than 5% of the engines total weight, because the turbocharge yourself is not very big, but at maximum power, output may increase by up to 25%. So it's a combination of the turbo charges lightweight on its ability to drastically increase the engines power output that increases the engines overall power to weight ratio should also briefly mentioned that a turbocharger in some respects is very much like a combustion turbine. We have a compressor on. We have a near inlet. We compressed the air within, burning in the combustion space within discharge it to a turbine. In this case, it would be a gas turbine, and we have exhaust out. And perhaps we have a generator. Or maybe we'll even use a combustion turbine for aircraft, so the concept is quite similar. 32. Supercharging: so hopefully enjoy that lesson on a turbocharger. Let me know if something is not clear. Please do send your comments. I really appreciate them on. If something isn't clear, I can always go back and edit the video or read Cut it on, explain it a little bit better. But now, as promised, let's do his short lesson about supercharger supercharging supercharging an engine performs the same function as turbocharging an engine. The difference is a source of power used to drive the device that compresses incoming fresh air in a supercharged engine. The air is commonly compressed in a device called a blower. The blower is driven through gears directly from the engines. Crankshaft, the most common type of blower uses to rotating rotors to compress the air. Supercharging is more commonly found on two stroke engines where the higher pressures a supercharger is capable of generating are needed. I'd say soup judges actually used for more high performance engines. Again, they do create a higher pressure, and there's also no delay or very little delay compared to a turbocharger. So you don't have super lag or anything like that supercharging the name. I'm not sure where it comes from because I think this is based more on someone's opinion, however supercharging, so it must be super great and a lot better than the turbocharger. 33. Exhaust System: exhaust system. The exhaust system of these legend performs three functions. One, the exhaust system roots. Suspend combustion gases away from the engine where they are diluted by the atmosphere to the exhaust system. Confines the roots of gases to the turbocharger if installed. Three. The exhaust system allows muffins to be used to reduce the engine noise. I've got to say I think the 1st 2 are fairly obvious. The idea is to get the exhaust gas away from the combustion space. You have to have a manifold or pipe to do this. So that's what the exhaust gas manifold does not So obviously A is. A allows us to use mufflers, which reduce engine noise, which nowadays is more and more problem. People want quiet engines that I want noisy engines. Diesel engines actually operates at a higher compression ratio. That means actually have larger parts and parts that are made to withstand larger pressures that makes him quite clunky. They tend to be quite loud. Some people would say quiet, stinky. In Germany, for example, they've actually started introducing now a diesel ban. That means if you go to the city of Hamburg, you're not allowed to drive a diesel engine through the city anymore. You're only allowed a picture or a gasoline engine, so diesel is in a way, perhaps gonna be phased out in the future. But this is a long, long time into the future. I think it's nothing that's gonna happen overnight. However, in some countries like a saying Germany from the pollution aspect, they're going to try and gradually face diesel out. Let's go and have a look at the exhaust gas manifold. So we regard exhaust guess manifold quite similar to the air inlet manifold. See that we've got free cylinders and the exhaust gas thing goes to exhaust gas manifold. Here, notice that the volume of the manifold is much larger than each of the intellects. So metaphor is quite large on Deacon. Take a large volume of exhaust gas. The reason we want to make the manifold large is because we want to get the exhaust gas out as quickly as possible. If we reduce the pipe diameter such as if we were discharging from the pipe here into a smaller pipe, then we're gonna have a big problem because get any source gets out is not gonna be very easy. So you want a pipe that increases in diameter and then goes to the exhaust gas manifold and that will allow the exhaust gas to get out off the cylinder very quickly. The other good benefit with a man afford which we discussed earlier, is that the pulsations air created every time we open the exhaust gas valves. We are going to smooth those pressure pulsations because with discharging the exhaust gas into the manifold, So that's another good reason to have a manifold weaken smooth out these pressure pulsations. And then afterwards, perhaps we'll have a muffler in order that we can make these pulsations or pressure pulsations quite quiet. Remember when you're hearing a very loud engine, that's true because you're here in the pressure pulsations you here in the well. If you don't want to hear that, then you can reduce these pressure pulsations before they're allowed to exit to atmosphere and everyone hears them, and you'll do that by increasing the pipe diameter before it goes to atmosphere. So that is their exhaust gas discharge line or source. Gas manifold 34. Operational Terminology: operational terminology before a detailed operation of a diesel engine could be explained. Several terms must first be defined. The next six lessons will introduce some terminology relevant to all internal combustion engines. The minor B six lessons. But what I'm trying to say is that the next few lessons in this section are going to be about the operational terminology. We're gonna learn about things such as bottom dead, center topped it, Cento clearance volume, etcetera. So let's get into that now. 35. Spark and Compression Ignition Engines: okay. Just a quick note here concerning spark ignition engines on compression ignition engines. Very quickly. Spark ignition engines are those that require gasoline or petrol. Gasoline. Fire on petrol fired is normally smaller engines. However, if you have a compression ignition engine, this is a diesel fired engine, and these are gonna be medium to extremely large sized engines. So I want to get out now because both of these engines come onto the fuel of internal combustion engines on although they broke onto the main internal combustion in June, will they come under the family? You could say the spark ignition engines on what side that a picture of gasoline or anything uses a on that these Lin Jing is on the other side. That's a compression ignition engine. The reason is the spark gives the initial piece of the mission required in order to get combustion going. That's petro and gasoline, or that the other side. These lending doesn't require a spark. The compression ratio is so high it's actually higher for a petrol engine gasoline engine. A person ratio is so high that when you compress the air and then after, the usual diesel will ignite one side. So that is the difference during Spark Commission and compression ignition engine is that's clean 36. Bore and Stroke: bore and stroke born stroke, a terms used to define the size of an engine. The board refers to the diameter of the engine cylinder. The stroke refers to the distance the piston travels from the top of the cylinder to the bottom. The highest point of traveled by the piston is called top Dead Center, whilst the lowest point of travel is called bottom Dead center. And there are 100 80 degrees of travel between top dead, center on bottom, dead center or one stroke. So I think about it like this. If we've got a two stroke engine when there is a piston and is at the top of its transit, that Piston is going to travel all the way down on, we're going to end up a place called bottom Dead Center distance that the piston travels is referred to as a stroke. And that's why we have to stroke or four stroke engines because it takes two strokes or four strips to complete one full cycle 37. Engine Displacement: engine displacement. Engine displacement is one of the terms used to compare one engine to another. Displacement refers to the total volume displaced by all the pistons during one stroke. The displacement is usually given in cubic inches, imperial or centimeters, which is metric so we can see here on the image Displacement in clearance volumes got displacement on the left on will measure that from BDC going up to T. D. C. So it's the full swept volume. Within one cylinder, we go down. We can see how we calculate the displacement value to calculate the displacement of an engine. The volume of one cylinder must be determined. Area equals pi r squared on volume equals area times length, so the volume of a cylinder equals pi r Squared times Hey H, where hate equals two stroke length. The volume of one cylinder is multiplied by the number of cylinders to obtain the total engine displacement, something that's all fairly clear. Concede displacement volume. Full swept volume from BDC All Web. Stevie C. We find out what this volume is for one cylinder, and if it's a 67 dredging, then we will multiply the swept volume in one cylinder by six to get the total engine displacement value 38. Degree of Crankshaft Rotation: degree of crankshaft irritation all events that current angina related to the location of the pistons. Because each piston is connected to the crankshaft, any location the piston corresponds directly to a specific number of degrees of crankshaft . Rotation The location of the crankshaft Can nb state is XX degrees before or XX degrees after topple bottom dead center. So we saw a couple of lessons ago, but we followed the crank webs. It was transiting around. Remember, it was rotating, was 180 degrees from top dead center, and then it rotated and went to bottom dead center. And then it's going to rotate backwards up to top that center again. Here, we've got a two stroke timing diagram. Now. These air really useful because we can see here at position to, in fact have regarded position one. That's probably a logical place to start. We start to compress the air in the combustion space position to we inject the fuel, then position three. We stop injecting fuel and then it positioned for we end our power stroke position. Four and five will be supports that are uncovered or some valves changing position. Then we scavenge. We pull the air in when we get the exhaust gas out, and then between six and one will have valves, reports that change position again on then we continue on the cycle. So that is Ah, two stroke engine timing diagram. And you can see we can calculate all of this just by looking at the angle of the crankshaft . And then we can figure out where the piston is. So if we know that we're a bottom dead center and we know that that particular piston is in the scavenging part of its cycle gets slightly complicated when used a four stroke engine when we have a four stroke engine timing diagram. But let's just stick without phenolic a system most simple one. So who have gone example? We've got the fuel injection may occur 10 degrees before top dead center, and this makes sense as fuel is injected shortly before the maximum compression stage is reached. After that, combustion takes place in the power stroke begins, so you can see we've got position to. That's where fuel injection begins. A position freeze where ends so will inject the fuel just before the piston reaches the top top. That center. Then we'll get our power stroke. Then we will get scavenging will change the the gas is getting exhaust gas out and get the Aaron and then we compress the air, inject the fuel, get admission, get expansion at power stroke, and then the process repeats. So that's our timing. Diagram works. And as I say, it's quite useful to have one of these because she can figure out where exactly the piston is in its linear travel or in its stroke, just by knowing the position of the crankshaft. As I've said before, though, for four stroke engine is slightly different because you might be born that center. But this could mean several things because there are four strokes, so a four stroke engine timing diagram looks quite different to this. It actually goes around twice, and you have 720 degrees. But from nightly can also pick out where the engineers in its cycle, as long as you know from what point the crank shaft is rotated and how many degrees it has rotated. If you've gone more than 360 degrees on a four stroke engine, then you've already done the 1st 2 strokes because one stroke corresponds to 180 degrees off rotation 39. Firing Order: firing order. Firing order refers to the order in which each of the cylinders in a multi cylinder engine fires will starts a power strike. For example, a four cylinder engines firing order could be 14 free to this means that the number one selling the fires, then the number four, then the number three and so on engines are designed so that the power strokes or his uniform as possible. That is, as a crankshaft rotates a certain number of degrees. One of the cylinders will go through a power strike. This reduces vibration and allows the power generated by the engine to be applied to the load in a smoother fashion than if they were all to fire at once or in our multiples. No firing order. 1432 This is quite a standard firing order. You're not gonna have a firing order. That's 1234 Because this unbalances the engine, you get quite a lot off vibration. If you want to think about what happens in men gin when you far on a cylinder, think about cannons on a ship in the past, in the 16 hundreds or so, if you were shooting cannons from the side of a ship. They would usually shoot them in stages. That which you one after the other rather and doing a complete broadside on firing them all at once. Later on, they did do complete broadsides. But the reason that I didn't do them in the earlier days was because they didn't know much about ships. Andi There was an instance in the past where one of the ships in the English Channel so they fired all the cannons on its maiden voyage on the ship, roll over to the side and sank was actually King Henry, the eighths flagship. And it's the effectively, the same for an engine. So you don't want all this cylinders firing at the same time, you want them firing at different times. In order you get less vibration, less mechanical stress on the engine on all together. The whole process is a lot smoother, so I see firing order 40. Compression Ratio and Clearance Volume: compression ratio in clearance volume. Clearance volume is the volume remaining in the cylinder when the piston is at T. D. C. Because of the irregular shape of the combustion chamber, the volume in the head. The clearance volume is calculated empirically by filling the chamber with a measured amount of fluid, while the piston is a TDC. The volume is then added to the displacement volume in the cylinder to obtain cylinders. Total volume on engines compression ratio is determined by taking the volume of the cylinder when the piston is a TDC, the highest point of travel, and administer the clearance volume, then dividing this value by the volume of the cylinder when the piston is at BDC, the lowest point of travel. So the compression ratio can be calculated by using the following formula. Compression ratio equals displacement volume plus clearance volume divided by clearance for you. So I displacement value. He's on left the entire blue shaded area where the mouse is, plus the clearance value. So that essentially gives us our whole cylinder volume from the top of the piston or the piston crown up to the cylinder head, and then we'll divide it by the clearance value, and that gives us a compression ratio. Remember, petrol engines could have a compression ratio of 721 to tend to one, whereas diesel engines will have a compression ratio ranging anywhere from 12 to 1 to 24 to 1 to gasoline. Petrol engines normally have a compression ratio of its 12. Diesel engines normally have a compression ratio of 14 23 to 1. Again, as I just stated, should actually read these lessons before. Perhaps so 8 to 12 to one is a far lower compression ratio for gasoline or petrol engine compared to diesel engine, which has a ratio of 14 2 23 to 1. The compression ratio is far, far higher for diesel engines, and that's why they're far more efficient than gasoline or petrol engines or one of the reasons. And again, I should read the next sentence before I start to talk. So anyway, we can see appear compression ratio in clearance volume, so the clearance value is simply the top section on the right here, which is the blue area on, and we've got displacement volume the blue area on the left, add them together, divide by the clearance volume and we'll get the compression ratio. So that's all of this 41. Horsepower: horsepower. PARIS The amount of work done per unit time or the rate of doing work for these engine powers rated in units of horsepower or kilowatts, indicated wars. Power is the power transmitted to the pistons by the gas in the cylinders. On is mathematically calculated brake horse power. First, the amount of usable power delivered by the engine to the crankshaft indicated horsepower could be as much as 15% higher than brake horse power. The difference is duty, internal engine friction, combusting inefficiencies and parasitic losses. For example, the oil pump, the blow of the water pump, etcetera. The ratio of an engine's brake horse power on its indicated horsepower is called the mechanical efficiency of the engine. The mechanical efficiency of a four stroke diesel is about 80 to 90%. This is slightly lower than the efficiency of the two stroke diesel engine, the lower mechanical efficiencies due to the additional friction, losses and power needed to drive the piston through the extra two strokes. Engines are rated not only and always power, but also by the talk they produce. Talk is measured, the engines ability to apply the power is generating. Talk is commonly given a unit of pounds per feet imperial or Newton meters, which is metric. So let's go to the top indicated or sparrows amount of power transmitted to the pistons. So that is directly the maximum of horsepower that we are generating. However, brake horsepower takes into account. All of the losses on brake horsepower is gonna be lower than indicated horsepower. The reason is, it's indicate horsepower minus all the losses, and that gives us brake horsepower the loss. Ease your engine friction. Combustion inefficiencies. I would say Paris City losses is going to be the big one. The oil pump, the blow of the ward upon the alternator, the air conditioning compressor. If you have one, there's a lot of stuff that is sucking away the power. And that's what brake horsepower is lower than indicated horsepower. If you can remove as many of these parasitic losses as possible, or remove anything that sucking away the power from the engine and the brake horsepower is going to increase. Ideally, you want to get it all the way up to the sames indicate horsepower. But this is never gonna be possible simply because you're always gonna have friction on components, which means you're always gonna have losses. The ratio of an engine's break course parents indicate horsepower is called the mechanical efficiency of the engine. The mechanical efficiency of a four stroke diesel is about 82 to 90%. This is slightly lower than the efficiency of the two stroke engine. The reason slower is because it has to do to extra strokes on talk. Is the force applied in a angular direction or in a rotary direction? Today's horse power originally has been called always power, because in the past they tried to estimate the amount of power that was generated by an engine by comparing it to the amount of power that a horse had. Obviously, he is a bit of leeway year because different horses have different strengths or different power on DSO. In the end, it was found not to be a very accurate measurement. However, the name stuck, and that's why they call it horse power. You will see for a lot of engines nowadays, especially the big ones, they rate the engine in kilowatts and you'll be more inclined, I would say to ask for the killer what to the engine on larger and medium sized engines. Then you will be inclined to ask for the horse power 42. Fundamentals of the Diesel Cycle: fundamentals of the diesel cycle. Diesel engines operate on the principle of the internal combustion engine. There are two basic types of diesel engines. Two stroke and four strike. An understanding of our each cycle operates is required to understand how to greatly operate and maintain a diesel engine. The next nine lessons explain how each cycle functions on their differences. It's not gonna be the next nine lessons. It's gonna be more like the next four or five, and I'm gonna explain to other two stroke and four stroke engine works. 43. The Basic Diesel Cycles: the basic diesel cycles. A diesel engine is a type of heat engine that uses the internal combustion process to convert the energy stored in the chemical bonds of the fuel into useful mechanical energy. This occurs in two steps. One the fuel reacts chemically burns on release. His energy, in the form of heat to the heat, causes the gases trapped in the cylinder to expand and expanding gases being confined by the cylinder must move the piston to expand. The reciprocating motion of the piston is then converted into rotational motion by the crankshaft to convert chemical energy the fuel into useful mechanical energy. All internal combustion engines must go through four events. Intake compression, power on exhaust, how these events are timed and how they could differentiates the various types of engines you can see here. We've got air being drawn in that let's just figure this out, says the Pistons. Going down the crank Web is rotating in this direction. Looks like we got compression power on, then exhaust, so it makes sense. So the air Inlet valve on the left is open. The Pistone represented here is moving down. The crack web is rotating. Will draw. Aaron will compress air. Noticed the vows era shut at the top will inject fuel will get a controlled explosion within the combustion space. The piston will then move downwards with crank. Web will rotate around, and then the piston will travel back up again. On will Expel are exhaust gases, So we've got intake of air compression power on exhaust. Those are the four strokes of a four stroke engine. In fact, actually here intake compression power and exhaust so you can see down in take off, compression down, power up exhaust. Another way to do this is suck squeeze. Thank blow Suck squeeze bang Blow sucks Grease Bang Blow that YSL that is happening within a four stroke compression ignition engine or diesel engine. All diesel engines fall into one of two categories to stroke or four stroke cycle engines. The word cycle refers to any operation or series of events that repeats itself. In the case of a four stroke cycle engine, the engine requires four strokes of the piston intake, compression power and exhaust. To complete. One full cycle, therefore requires two rotations of the crankshaft, or 720 degrees of crankshaft rotation which is 3 60 times to to complete one cycle in a two stroke cycle engine the events intake, compression, power and exhaust occur, and only one rotation the crankshaft or 360 degrees. Now we know already that two stroke cycle only occurs over 360 degrees of crankshaft irritation, because we learned that a couple of lessons ago when we were talking about degrees of rotation and we can see intake compression power exhaust that all happens within 360 degrees for a two stroke, However, for a four stroke engine will need twice that number, which is 720 degrees. So 720 degrees, four stroke, 360 degrees to stroke. But that's a typical four stroke cycle there. If you got remembering, take compression power and exhaust. Then just members suck, squeeze, banged, blow, suck, squeeze, bang, blow bursting. I find it's actually easier to say something. Please bang blow than intake compression parent exhaust so lays all those are the basic diesel cycles 44. Timing: timing in the following discussion of the diesel cycle, it's important to keep in mind the time frame in which each of the actions is required to occur. Time is required to move exhaust gas out of the cylinder on fresh air into the cylinders to compress the air to inject fuel on to burn the fuel. If a four stroke diesel engine is running at a constant 2100 revolutions per minute or rpm , the crankshaft would be rotating at 35 revolutions or 12,600 degrees per second. One stroke is completed in about 10.14 to 9 seconds. As you can imagine, timing is critical to the successful operation off the engine. This is completely true. Timing is everything on. In order for the entire engine to work together effectively, we have to ensure all of our valves open at the correct time. The fuel is injected at the correct time. The piston moves to the correct position at the correct time, etcetera. So all of these mechanical items have to work together to complete a single task which is to generate power. This is actually easier to achieve than you might imagine, and it's quite astounding. When you think about it. You can have something rotating that thousands of revolutions per minute on. There's no problems. I mean, people who really take combustion engines for granted their absolute miracles of engineering on. Nowadays, we don't really appreciate them because we just take it all for granted. So timing is pretty much everything. And I think we've realized that from my camp chef videos as well, where you could see that if the camps halftime was off just by a little bit, then we're gonna have problems with our engine on our valves and he in those maximum pressures required to extract the maximum power from the engine. 45. The Four Stroke Cycle: the four stroke cycle. The four stroke diesel engine cycle consists of an intake, compression power and exhaust stroke. You can click on the image below to view of working for stroke engine cycle. The link to this model is in the pdf supplied, so check that out. We won't do it right now because we're going to do that in the next video. How does a four stroke engine work four stroke gear ratio in a four stroke engine? The camps left is geared so that it rotates at half the speed of the crankshaft. This means that the crankshaft must make to complete revolutions before the camshaft will complete one revolution. The following lesson will describe the four stroke, normally aspirated diesel engine, having both intake and exhaust valves with the 3.5 inch bore and four inch stroke with the 16 1 compression ratio as it passes through one complete cycle. If that this is not true, we're not going to do this lesson that we have in several E because I'm going to explain that you using this model. So the important thing to remember here is simply that a four start changing has a camp chef that is geared so it rotates only half the speed of the crankshaft. That means the camp chef will do one full rotation when the crankshaft does. Only 1/2 rotation with a two stroke engine is different. The camps after big eared so they runs directly in sync with the crankshaft to a normally aspirated engine, is one that does not utilize a turbocharger or supercharger. Normally, aspirated means that you're not compressing the air. You can think of aspiration. Aspiration is when you're breathing in and out. The engine does that as well On If we have a turbocharger supercharger, it's no, a normally aspirated or naturally aspirated engine because we compressing the air in. However, if we don't have a server charge of supervisor, then it is a normally aspirated engine. So next lesson, more look at the four strike engine and how it works 46. How Four Stroke Engines Work: John here in this video, we're going to look at a four stroke combustion engine on. We're gonna run through some remain components and let me show you how it works. So let's pause the animation for a moment. We can see here. We're looking at the internal parts of a combustion engine. Specifically, we're looking at a diesel combustion engine. Weaken tell, because if we look up here, we can see a fuel injector conceded fuel coming game for the brass piece and we could see the injector. His house between all the valves is this piece here on the injector will inject fuel into the combustion space that is our injector nozzle there. So that's how we can tell it's a diesel engine and not a petrol gasoline engine. Let's look at some of the components in the engine very quickly, and then we're going to discuss how it works. We got here a frank shift that's besides him here. We've got pranked whips that's the side from here, and the cramp webs connect to a comrade, and the Konrad connects to Piston Square. Wrightson on the Piston is moving up and down linearly within a cylinder liner it's back this up for a moment and see it is moving upwards. Well, pause it there and now it is moving downwards. Up, down, up, down. But we can see that linear motion being transferred to the lower species on it is no longer linear. It is actually rotating around what we call angular motion or rotational motion or rotary motion on assists. Rotor emotion when attached to, for example, a shaft in a car that allows us to drive the wheels. And it's going to allow us to rotate the wheels. We can see here a couple that on perhaps to a chef on that shaft within connect wheels. And that's how it would move a car. But how? Getting all of this motion. Well, let's go right back to start again. We can see here. We've got blue blue indicates air on red indicates exhaust gas or heat so the blue face is currently occurring. Can see that these valves were open image. Assuming a second, these fallacy were previously open again. These files zero now are you. The two valves are inlet valves, one valve. That's another we can see. Just zoom out a little bit go. They're coming in here and air coming in here. There's a inlet valves. So there is coming in and it's going into a combustion space. What's gonna happen? Ease the air. Once who filled up the entire chamber, The Air Inlet lives are gonna close on. We're gonna compress the air on when we've compressed the air. We're going to inject fuel while just miss that back up again. Back it up slightly there. So some fuel being injected a moment ago. There one more time. Look around here. That was the fuel being injected. When we injected the fuel, the fuel was vaporized as it came out of the nozzle on. Because it mixes with the air, we get a very nice air fuel mixture. This fuel then ignites due to the high pressure and temperature within the combustion space . This is actually called a compression ignition engine because we're using increased pressure and temperature to ignite the diesel fuel. So it's a compression ignition engine. And once the fuel has been ignited, the diesel we're gonna get power stroke and the power stroke is symbolized here by the red color. And the power stroke has pushed the piston downwards because when we ignited the fuel, we've got very high temperatures. Very high pressures on this force, the piston back downwards. But when the piston gets to the bottom, it is effectively a new spin around here. I'm gonna be forced back up again. What's that? As it's forced up, exhaust gas valves are going to open. We've got some exhaust Gas 1000 the other side considers to policy. They are now open that exhaust gas because member would burn the fuel. So what we've got now is just waste products, a lot of carbon. And we need to get that out of the cylinder liners quickly as possible in order that we can recharge cylinder and star power stroke again. So we're lengthen those exhaust gas valves, exhaust guests going to go out, and then we're gonna draw fresh air in again, and I see air comes in. And then we didn't inject fuel. They were going to get power strike, and then we're gonna expel the gas again. Andi, we're gonna repeat that it's actually happening quite fast. I see broken time it correctly and it was open there being something fuel being injected, power stroke, So it's gas being expelled. Be something compression. Fuel injection, power stroke, exhaust gas being forced out on duty. So what we've got is suction compression, ignition exhausts, suction, compression, ignition, exhaust Suction. Compression was suction again. Is the animation is a bit weird, but the point is suction compression, ignition exhausts Is all those happening was sucking in the air, were compressing the air, rejecting the fuel We're combusting the fuel or causing it to night. We're having our house stroke were expelling the exhaust. Guess on the only reason we're doing all of this because we want that piston to go. Oh, down, up, down, up, down. So it's coming up. Then we're gonna compress the air, Inject fuel, get a controlled explosion. The increase in pressure and temperature is gonna force the piston down. That's how power stroke on. Then we're going to need to get rid of that exhaust gas because we extracted all the energy from the burn fuel so will force the system back up again. It's going to expel the exhaust gas on since rock fear will open the air in the valves and will suck area on our way down on. We'll repeat the process. So it's called a four stroke engine because we need four strokes in order to finish one complete cycle. For example, suction compression, ignition exhausts. So suction compression power exhausts, suction compression, power exhaust. So those our four strokes and that completes one full cycle, and that is how a four stroke engine works. Don't get worried. We're going to talk about that in a lot more detail for out, of course. Or at least we're going to look at all of the components. Ondas get more familiar with the components. You're gonna understand the whole process. You're really gonna explain to you how the valves know when to open at the correct times. Remember to Aaron 1002 exhaust gas valves any to open at the correct time in order that we can get the source gas out when it's supposed to go out and get the area when it's supposed to go in. We also need to know when to inject the fuel on. We're going to discuss all those concepts in this course, but anyway, that's our four stroke engine works on. I hope that's all clear 47. The Two Stroke Cycle: the two stroke cycle. Like the four stroke engine, the two stroke engine must go through the same four events intake, compression, power and exhaust. But a two stroke engine requires only two strokes of the piston to complete one full cycle . Therefore, it requires only one rotation the crankshaft to complete a cycle. This means several events must occur during each stroke for all four events to be completed in two strokes, as opposed to the four stroke engine, where each stroke contains roughly one event in a two stroke engine, the camshaft is geared so that it rotates at the same speed as the crankshaft, which you want to want. The following free lessons will describe the two stroke engine, etcetera, etcetera. When actually going to do that, we're just gonna load up a two stroke engine on. Then we're going to look at how it works. So if the terms intake compression, parent exhaust, steam aliens, you or difficult to member can always try suck, squeeze, bang, blow and I find this works a lot better. So let's now go and have a look at how a two stroke engine works 48. How Two Stroke Engines Work: in this lesson. We're gonna look at the two stroke engine. We're gonna have a look at some of its main components. Then we're gonna look at how it functions. We'll look at some of his applications on then finally, we'll look at some of the advantages and disadvantages with this type off engine. So here we have a three D model much the same as before. Although this time is interactive on. In order to do this video properly, I think the first thing we need to do is quickly go through some of the main components. Let's start at the top. We can see we have a spark plug. Sparkplug is used for igniting the air fuel mixture within the NJ. We're going to get to in a moment. We've also got a combustion space necessary here. We've got a port on the side and see the Black arrow exit in. That is our exhaust port. We've got a piston. Is this whole section here? Andi? Then on the left hand side, we've got another port. It's just uncover it. I can see now wear the orange and blue arrow is that is going to be a transfer poor concedes coming away up here and finally on the bright we've got, uh, in take port section here on we go down. Finally, we got the rest of the engine which sits within the crankcase, which is within this red barrier got crank web. We've also got the crankshaft which can see in the back here that runs all the way along all the way through to the end load. So that is a two stroke engine. Let's zoom out again so we can have a proper look at the engine on. We'll work through now how it functions. So I think the first thing we want to do is follow the air fuel mixture and then go right back to the start. You can see that the air fuel mixture starts here, and it comes in through this poor traveling left, and it's going into the space below. The pistol can see the piston at the top of the screen on. We can see that as the piston comes down, it's gonna compress that air fuel mixture so it's come down. The air fuel mixture, which has traveled in it, was happily just sitting in the crankcase filling up this whole space. But now, because the piston has travelled downwards, it's compressing that air fuel mixture on the pressure within the crankcase is increasing. Play on what you have it further. What's happened now is that the air fuel mixture inlet or the intake port has been closed off by the piston, so we're not gonna get any more air fuel mixture traveling in this way. The fuel, by the way, is going to be petrol. Gasoline. Gasoline is what is referred to in the states and other places like that, whereas in the UK we tend to referring more to US petrol. So this intake port is now totally closed. But what's happened is as the piston has moved down and compressed air fuel mixture here, it has forced the air fuel mixture out this way through the trans for port on the piston has uncovered the transfer port on the air. Fuel mixture has been allowed to travel him to the cylinder. Lina, push! Play again and see. Now it's flowing quite freely into the cylinder. Lina the piston looks like it's now reached bottom, Dead center. That's the lowest point of its linear transit. So bottom. That center would be about here on top. That center would be about here and now because it's reached bottom. Dead center. It's time for the piston to move back up again. Notice pistons moving up and down linearly on down here. We've got something called rotational or angular motion. It's rotating circular direction, whereas the piston is linear, so let's watch the piston move upwards. The piston is now closed off the inlet to the transfer poor. So we're not gonna get more flow coming into the cylinder. Lina, let's go Over here. What's happening on this side? We've got another port that's open the exhaust port. Going to see that that is now also closed. So we've got all of the's top two ports closed. Only the bottom one is open. And what is happening now? This is where it gets really interesting that if your mixture is gonna be compressed on the pressure is going to increase drastically on DSO is the temperature. So the pressure and temperature within the space is going to increase. The volume is going to decrease because there's simply less space. Let's let the piston travel up on a about this point here just before he gets the top dead centre or the top of its travel, we are going to get a controlled explosion. That's just so you mean we can see here. In fact, we can actually see the little spark has been created by the spark plug. This piece here is called the Central Electrode. On with charging this with high voltage at some point electricity or the pieces here, the central electrode in the piece below it. They're gonna be so charged that the air is going to become ionized and we're gonna get a spark that jumps across the gap. This spark is quite hot, and it has more than enough energy to light that hot, highly pressurized fuel air mixture. When the spark occurs, we're going to get a controlled explosion. So some zoom out now can see a controlled explosion that controlled explosion is gonna force the piston down. Nice pistons going back down linearly on we have Essentially, they just had a power stroke. So we've got power from that fuel mixture because by having an explosion within the spice, we can then harness the energy that was created by that explosion on when we harness that energy. What it essentially means is we're gonna use the energy to push the piston downwards on eventually will turn into rotary motion but noticed that on the right hand side, that stroke itself or its movement thou it is very short. The exhaust gas port is already opening. Conceive the gap here, let it play it for the exhaust gas sport is now fully open. So we've extracted are useful work on now The fuel air mixture, which was originally used to create explosion, is nothing more than exhaust. Guess now we want to repeat this process many, many times as quickly as possible. The reason we want to do that is because the faster we can do it, the more power we can generate and the more useful work we can get done. So in order to do that, we've got to get rid of that exhaust gas quickly. And that's why we uncover the exhaust port. First on, we let the exhaust gas just escape if we let the piston continue down or in fact, if we traveled down a little bit further, we can see the original air fuel mixture intake on the right hand side is almost closed. There is only a small gap around here. It is now closed, and we are going through the same process again. The piston is gonna move downwards, is going to compress the air fuel mixture in the crankcase. It's going to force the air fuel mixture out through the transfer poor. It's gonna go into the cylinder, Lina, and we're gonna repeat that whole process again. So let's watch the animation on. We'll do a quick, very quick recap. So down here, air and fuel into the cylinder space closed the transfer poor. Closed the exhaust port. Increase the pressure and temperature. Ignite the fuel air mixture. Get a controlled explosion. Get out. Power stroke up to this point now zooming slightly. Open the exhaust port. Get rid of our waste gas Recharge cylinder on. Repeat Now this is actually what they refer to as a intake compression power X sourced cycle. This means we are let in air and fuel into the cylinder space. That would be our intake compression because we're compressing the air fuel mixture power because we're extracting the power exhaust because we're then exhausting the waste gases on then repeat. If you remember that, just think off. Suck squeeze Bank Blow, suck squeeze, bank blow. That's all the engine is doing. So let's go through it again, right? Squeeze, bang, blow, Suck In the left hand side, I'm traveling upwards. Squeeze bangs back down. Blow, suck, squeeze, bang, blow fat. Let's speed up a bit. We can I should have a look at it. There we go. So now it's really getting going on. This is essentially what is gonna happen in your to strike engine, except it's gonna be happening thousands of times a minute. Let's go back to a nice graphic because I think that one shows better. What's happening so again? Here we g o. So you can see the suction left hand side squeeze, compression, bang, blow, suck, squeeze, bang, blow, etcetera, etcetera. I think you've understood that now it's quite nice. With this animations. We get the nice explosion at the top, and there we go all the way through the cycle, over and over again. So let's now have a look at some of the applications off this type of engine. Two stroke engines are generally used only full small applications and talk about small applications are mean things like motorbikes or perhaps an outboard engine for a motorboat or perhaps a long muller relatively small applications. There is one exception. You will see this type of engine used for very, very large merchant Navy vessels. What? I mean, here is ships, container ships, oil tankers, all these huge ships. They will use two stroke engines. The advantages with a two stroke engine are that there are very few parts is design is very simple, and it has a very high power to weight ratio. But the disadvantage was two stroke engines is simply that they are no very efficient. If we go after animation now, we can see that as the piston is coming up, we're gonna get the explosion on almost immediately. Within a very short space of time. We have to open the exhaust port so we can only extract so much energy. In fact, very little that is our power stroke. If we can make the power stroke longer, we can extract more energy than a two stroke. That isn't really possible because we need to get the exhaust gases out quickly again. And to make this even worse. When we open up the transfer poor, we're even gonna waste the air fuel mixture. So it's coming in. It's gonna fill up the space here, but we want to feel it up as much as possible. I'm forcefully. That means that we're gonna get some of that air fuel mixture going back out. The exhaust poor. Not much. But it is gonna go out and this gives us another drop. Inefficiency. There's no point sending all the air and a little bit of fuel there if it's just gonna rush out the exhaust port without doing any useful work. So that's a big disadvantage with two stroke engines. 49. Final Thoughts: So you made it sound very happy to see you here, but I can't see you. By the way, I'm very happy watching this video because it means you made it to the end of the course. I really do hope you enjoyed the course I tried to make. It is interactive as possible. I really want to tell you visualize what's happening inside the engine. But my sport thing to me is that you have fun learning. I really do hope that he take that knowledge, apply it on. Maybe you could pass it on to other people. I think teaching people and helping people learn Israel gift, especially other person appreciates it on by this course will maybe to do that. So it's flight from me. For now, however, feel free to check out. Some of the of course is the wrong line. They're all predominantly about mechanical electrical engineering at the moment, or there is a bit of power generation coming through. And like, say, I really do hope you enjoy the course. Thank you very much for your time, the time you invested in the course on and I hope to see you, another coursing What's in it 50. BONUS How A Centrifugal Governor Works: today, we're gonna look a centrifugal governor on. I'm going to talk you through some of the components, explain how it works and what it was actually used for. Now, the word governor actually means boss in English for chief on. The reason has that name is because it was used for control applications and it would control, for example, the speed often engine, that the term governor is still used today. Although obviously things have moved on the last 150 years on, we don't really have mechanical governors. Or especially not like this. We have more Elektronik governors, although there are some mechanical governors available, but it's not as common as it used to be. So it's diving now and have a look at some of the components we can see below the governor . We have a bevel gear arrangement. That's these two gears here. One is vertical wanted horizontal as a bevel gear. We can see the drive shaft coming in along these horizontal actually hear through the wall on the drive Chef will be coming from, for example, and engine on it will be fed from some sort of gear or pulley arrangement, so as it comes through, it's going to drive the gear on the top, the one that's horizontally orientated that's going to spin on. Then we're gonna come up here to ah, centrifugal Governor Centerview. Governor is the whole piece of apparatus that we're looking at now at the middle or in the middle with actually spindle on the lower section. We have a sleeve for sliding sleeve on the outside, the two round object you looking at. These are waits. Refer to his fly balls, and then we got to linkages and to arms. Now what's gonna happen is as the centrifugal governor accelerate. So as the whole thing spins, you're going to see the sleeve. The low piece moving up and down on as it moves up and down, is going to move this link each. This whole arrangement here on that is going to then open, or at least change the position off this valve in there. So I've talked you through how it works, but I probably should have just showed you would be a lot easier. So let's check it out. So now it's spinning and it's been quite slowly now it's increased in speed, so the spindle has moved up slightly, reaches back that up again. I can show you again, spinning slowly, increasing speed to fly balls move out. And now they're at their for this position. Notice that the fly balls now are extended further out from the sleeve. Then they were originally So what's happening is an engine, for example, will be rotating at a certain speed. Let's say 100 rpm and it's gonna rotate the horizontal shaft at 100 rpm, assuming that the horizontal shaft is geared directly. So we got 100 rpm on the horizontal shaft on. We're going to transfer 100 rpm through the bevel gear here and to the centrifugal governor . If we back up now, we can have a look at 100 rpm. Should start off. There would be, Oh, so you know it's the arms are no particularly far away from sliding sleeve. But as we increase speed, let's increase now to 200 r p in the arms have moved further away. They're getting thrown further away by centrifugal force. Now, if we speed it up even further, we can see the arms now really quite far away from the main stem or the spindle. So as we increase in speed, the weights or the fireballs are gonna get thrown further and further away from the central stem on as they do this, they are going to put up this sliding sleeve, which is this section here. Concede the linkages only allow them to travel so far. And as they move out the weights, they're gonna pull this interest, leave upwards. So we've got three different speeds there. 100 rpm, 200 rpm of 300 r p en. On. We know that as a increase in speed, the bulls will get thrown further and further outwards until they reach their maximum limit . So all we do really is taking the speed of the engine on were sort of representing that by this this governor. But the governor has been connected to this leave a type arrangement, can see it's jumping from there to there, and then it's jumping down on if we spin around using coming along here to their to their on Finally, you can see gotta control shaft coming through comes through the wall through the point on . We have here a vows. I said you got here valve looks a bit like a butterfly valve. Very old one. Onda we can do first again. I'll try. Get the government into the picture at the same time, we can see the valve. So seven look. Okay, so the governor has slowed down. Now we're 200 off again on this valve now is only, say, halfway open. So that's something we call throttling. And if we go again, is now pretty much fully open. When we can see the governor and see the arms have come down again, see if it come down further. That's a slow is we go OK, so soon? I can't let's from through that again. Just live with more. Okay, change position. Now it's throttled because it's run a 200 up in on now it's running 300. Let's imagine that's it very, very fast on the valve. He is now closed. So why would we set up that centrifugal governor like that? What's it actually doing? Well, the reason we set it up like that, it's imagine that in this pipe here is a lot of steam. So you're I'm a bit of steam coming along here on it gets stopped by the vowels, which play right. The vowel now is throttled. It's half open, which we know is 200 rpm on. The steam can flow through again. So what's gonna happen now? So look, you go backwards. It's flowing through. However, maybe the engine or whatever is the steam that's coming through there has not taken effect yet, so the engine has not accelerated yet. Imagine we gotta steam injure so we'll keep playing it. Now it's fully open, and if we're allowing all of that steamed, passed through the valves and go to a steam engine, then the steam engine should start to accelerate again. And that's exactly what happens. Look, see, now it's accelerated on now is a brain and maximum speed or near maximum speed. So we want to close the steam inlet valve, and using this arrangement, we can control them out, steam fed to the steam engine. And then if we control amounts thing going to steam engine, we can control the speed off the engine on this is really cool is a very simple way to control the speed of the engine. It means we don't have to have somebody there constantly opening and closing a valve, and it does it'll fully automatically. And that is essentially what centrifugal governor does again. Now we're fully open. One, the engine to increase in speed engines increased. So close the valve it. Now it's going too fast, and we've completely closed a valve. That's it. And it will toggle between these sort of three different positions, and you can set them up so they're a lot more accurate. So the tolerances are sort of a lot finer. For example, imagine you wanted it to operate between 1300 rpm and 1500 rpm in. Then you can set the valve up on the governor to operate like that accordingly. It's a very old design, but very simple. The Victorians really didn't know what they were doing concerning mechanical engineering, and first thing, I find it quite a wonderful piece of machinery. 51. BONUS How Spark Plugs Work: in this video, we're gonna look at the spark plug. We're gonna look at where the sparkplug is used in what type off Ng's rules. They're gonna look a spark plugs. Mein Kam Parents, we're going to look at how it works and then we're gonna discuss some concepts such as hot and cold spark plugs and sparkplug reach. So that's diving. You can see a spark plug in front of us now. These are interactive freely model off a spark plug. Spark plugs are used in gasoline on petrol engines. We were first of fuels gasoline in the States and places like that, whereas in the UK, we refer to his petrol. The fuel is the same. Just two different names and we use a spark plug to ignite this petrol or gasoline. We can see on the video now that we're looking at a two stroke engine and as the piston approaches top dead center, there is a spark from the spark plug on this bark ignites the fuel and then we get out power stroke. So that's what it's doing. But now let's look at the comparatives and then figure out how we're getting this spark. Okay? So you got a spark plug in order to figure out works. Gonna need to look at some of the components. So I'll take a cross section. We'll work our way down from the top. We can see we've got a terminal connection on the top for a place where we can connect the high voltage that is created by the ignition coil. We're gonna actually talk about the ignition system in a different lesson, However, the ignition system supplies a very high voltage to the top of the spark. Look to the connector will determine all at this high voltage is gonna be in the range of between 20,000 to 40,000 volts. We're going to connect that high tension voltage to the top of the spark plug. This high voltage is actually then transferred through the spark plug through a central electrode. So it's going to travel down through the spark plug. This black area here would actually be a piece off copper on this is that conductor to call at least central electrode. When we get to this piece here, this jagged area, this is actually a resistor, and I'll explain to you what it does a bit later on. But the high voltage will The current, I should say, because it's a currently actually flows gonna flow down this way through the resistor down along the central electrode, further down, further down through the spark plug, nose or the insulate er tip and then all the way down to the bottom of the central electrode. We can see the central electro terminates here, and there's a gap on the peace on the lower side. Here is called the ground electrode, But the ground electrode, as you can see, is not connected directly to the center electrode. There's a gap here will actually call this air electrode gap. It's quite important because the lies you made the gap, the higher the voltage that will be required in order to jumped the gap on Get a spark. Before we talk about that, let's go up and discuss some of the other components quickly. We can see we've got a screw thread on the side that allows us to screw the spark plug into the energy. We've got a washer, and then we've got a outer casing section here on your motive, says we get up. We've also got a hex. Not this bit. That allows us to tighten the spark plugs into the engine or to loosen it off again. On this white shiny piece is our porcelain insulator Porcelain insulator is there to stop? The voltage leaking out from the top were leaking from the top on trying to get to ground along this route Here. If we have a piece of metal that ran from, for example, here are terminal connection all the way down and connected to here soon and show you that again down here and connected to here. Then the voltage would travel from the top on the terminal connection all the way down on. We would get a short circuit. We just have a lot of electrons are just flowing straight down to ground because his lower piece of sparkplug well, this section here is grounded on the engine. So in order to prevent that, we have this porcelain insulator. Porcelain is a very good insulating material. And we actually use this on high voltage bushings such as for transformers. And we have this route shape to increase the path that is required by the voltage to get to ground. If we had a straight line from here to here on the porcelain insulator, Then the distance to ground would be a lot less than if we have this rip shape. So that's what I have the roof shape. It's to make it harder for the voltage to get to ground because it has to travel across more of the insulate. Er, I mean, you'll see this same effect on large transformers. They also have very large bushings and have weird shapes. But the concept is saying we're just trying to make it as difficult as possible for those electrons to flow to Earth. So that's that porcelain insulator. So we connect returns to the top current flows in and high vaulted. It flows along. I center electrode onto a resistor. Now the resistor is there to reduce the amount of electrical interference or noise that is created when we get our spark created by the spark plug. People refer to this as electromagnetic interference with radio frequency interference. So what, Rex again is a lot of electromagnetic noise that interferes with other electronic circuits . Remember a lot of electronic circuits that you use on a day today basis with your smartphone, we radio or even engine control unit. Those are operating a 1,000,000 volt, so it doesn't take much electrical interference in order to make them act slightly abnormal . And it's the resistance spark plug that reduces the electromagnetic interference from the spark plug and stops it affecting all the gadgets and gizmos that you would normally have within your car. Let's go down the central electrode a bit further. I've actually got into the insulate er knows that's this whole section here on the insulate er again is insulating the central electrode from the body and see, we've actually got insulation for out the entire sparkplug to ensure that the voltage or the electrical current flows only through the central electrode resistor and does not try and get through the insulator on flowed to ground. So the insulation is very important. Go all the way down. Now we get to the base of that spot plug and we can see now the anything that's gonna happen to complete the circuit is that current has to flow down this way and jump the gap. The reason we have such a high voltage is because we want that high voltage to iron eyes. The air in this area, if you want to learn more about this, is actually called dialectic breakdown strapped for dialectic strength. But what it essentially means is the high voltage is gonna try to jump the gap here by ionizing or of the gas in this space. If it can ionized gas in this space and that guess is going to be able to carry electrical current. And if it can carry electrical current, if it becomes a conductor, then the electrons gonna jump across from the central electrode to the ground electrode actually call this and arc. This arc has a lot of energy and a very high temperature, and it is high temperature and high amount of energy that's going to cause a fuel air mixture within the combustion space to ignite. So the fuel in this case is gonna be gasoline or petrol. It's not gonna be diesel. Once we get admission, they were going to get a power strike. Now the ground electrode is called ground electrode because it's connected to the ground. Or I should say it's actually grounded on the engine and electrons love to flow to ground. You may have noticed this. If you have a look at a thunderstorm, there's a reason we get lightning. And that's because there's a lot of electrons, a lot of electrical charge that's built up in the clouds, and it wants to get to ground. And we see these electrons trying to get to ground because they appear as bolts of lightning. That's essentially what's happening here. These electrons that have flown down the central conductor. They also want to get ground, and they're going to jump or arc across the gap on flow to ground through the ground electrode. That's this entire piece here on the engine. In this case is serving as the ground. You may hear people talk about sparkplug reach spot what reach is actually the distance from the lowest part. To thread on the spark plug up to roughly where the washes as indicated. Now you see what they refer to a spark plug reach, and it's quite important that if you're changing spark plugs, you ensure that the reach for the new spark plugs is the same as the reach for the old spark plugs. The reason is if you put a spark plug into the engine that has to longer reach. You may even connect the spark plug with the top off the piston. As you can imagine, this is good because every time the piston comes up, it's gonna bang against the ground electrode. In addition to that, you'll actually get called deposits that build up on the spot plug Fred within the combustion space. So it's very important that when you change part plugs, you ensure that the reach of the new spark plug matches that of the old spark plug he lost in here. People referred Spark plugs has being either hot or cold. They're actually just talked about the thermal characteristics of the spark plug. If we have a hot spark plug, it means it heats up quite easily. And if we have a cold spark club, it means it's quite resistant to absorbing Heat. A hot spark book who have a long thing insulated knows there is a cold sparkplug. We'll have a sure fat insulated knows because the cold spark, like has a shorter and fatter into later knows you can get rid of the heat a lot more quickly. He's actually rejected to the cylinder, head of the engine on then, typically to the cooler water system. Although some of the he will also be lost to ambient air, Hot spark plugs could be used for things such as lawnmowers. He's a small engines that don't have a very high operating temperature was specifically, they don't have very high operating temperatures within the combustion space. However, high performance engines do have very high pressures and temperatures within a combustion space. And for this reason you need a cold spark plug in order to get rid of that heat as quickly as possible. So cold spark plugs have a very short thermal reject path. The heat range of the sparkplug is given on the spark plug. It'll be usually indicated on the porcelain insulation, and typically it's gonna be a number within the range off 1 to 11 or 1 to 10. But it depends upon the manufacturer off the spark plug. If we go back to a little more example, we know that the engine is generating a relatively low amount of heat, so we're going to look for a low heat range sparkplug, and that means we're going to look within the range off 2 to 5. Typically If we look at a high performance engine, perhaps of racing car, then we are gonna have a high heat range because there are high temperatures. So we use a cold spark plug with a high range, and this may be as high as 10 or 11.