Internal Combustion Engine Basics (Mechanical Engineering) | SaVRee 3D | Skillshare

Internal Combustion Engine Basics (Mechanical Engineering)

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15 Lessons (1h 45m)
    • 1. Course Overview

      1:36
    • 2. Welcome

      4:37
    • 3. Engine Exterior

      2:15
    • 4. Common Engine Components

      5:43
    • 5. How Two Stroke Engines Work

      14:33
    • 6. How Four Stroke Engines Work

      15:25
    • 7. Petrol vs Diesel

      7:33
    • 8. Lubrication Oil System

      8:47
    • 9. Fuel System

      2:47
    • 10. Air and Exhaust Systems

      8:27
    • 11. Cooling Water System (Jacket Water System)

      6:41
    • 12. Cylinder Sleeve

      5:13
    • 13. Electrical System Part 1

      5:58
    • 14. Electrical System (Part 2)

      6:56
    • 15. Final Thoughts

      8:24

About This Class

Learn how internal combustion engines work! 

Internal combustion (IC) engines are not only used in the automotive engineering and automobile engineering industries. They are used to rotate pumps, generator rotors, fans and many other machines. But what are internal combustion engines? Why do we use petrol/gasoline and diesel fuels instead of just one type of fuel? And how do these astounding machines work? This course will answer all of these questions and many more!

You will learn:

  • How two stroke engines work.

  • How four stroke engines work.

  • How internal combustion (IC) engines work.

  • What the differences between petrol/gasoline and diesel engines are.

  • How petrol and diesel engines work.

  • Identify all of an engine's main components and their function (crankshaft, piston, camshaft etc.).

  • Know all of an engines ancillary systems and what they do (oil, fuel, water etc.).

Irrespective of your background, learning about internal combustion engines will benefit you greatly. They are used as prime movers in cars, vans, trains, motorbikes, scooters, lawnmowers, leaf blowers and many other machines. So even if you are not an engineer, or training to become one, the knowledge you gain will always be useful, because a combustion engine is never far away!

Interactive 3D models have been used to show you every engine component in detail.

3D animations show how each engine and component works.

2D images have been used to highlight areas of interest.

Hope to see you on the course!

Transcripts

1. Course Overview: in this course, we're going to be learning about the internal combustion engine. You're going to learn how a four stroke engine works, how a two stroke engine works, how a diesel engine works on our gasoline or petrol engine works. We're gonna use interactive three D models so that I can show you all of the main components of the engine from the exterior side on. Then we're also going to use three D models so that you can look at the interior and see all of the parts working as they would in a normal combustion engine. By the end of the course, you should be able to identify visually all of the main components of a combustion engine, both internally and externally. You'll also now a two stroke engine and a four stroke engine works, and you'll be able to list some of the differences between a gasoline engine on a diesel engine. So if you've ever wondered what's under the hood, then this course is going to teach you exactly that. You don't need to be an engineer or a mechanic to understand how a combustion engine works . The design is over 100 years old, And with the help of these visual aids, like three D models, three D animations, quite quality images and crystal clear sound, you're going to be able to learn a lot about engines in a very short space of time. Check out some of the free preview videos, see View like my teaching style. See if you can understand the content, and if you do, then I hope to see you on the course. 2. Welcome: Hi and welcome to this Savary course. My name's John Russell. I'm going to be your instructor throughout the course. I've got about 17 years experience as an engineer. I started out when I was 16 and I trained as a Marine engineer on large container ships. After that, I worked in a superyacht industry, and then later on in my career are busy power stations and minds chocolate factories, biodiesel plants, glass factories on pretty much every other type of factory you can imagine. And slowly, over time I managed to build up my engineering experience. I'm gonna try roll some of that experience into this course. I'm not just going to teach you about engines and components, etcetera. I'm also going to tell you a few stories and pass on some my own experiences so that you can learn from case studies on a lot of time. You can learn from when things went wrong for me, which of them honest seemed to happen more than I would have liked. How am I going to teacher while I'm going to teach you by using interactive three D models , Interactive three D models, allow me to rotate the engine life. So So you mean do now pan around because I'm using this every interface. I can also show you a notations, and that will allow me to elaborate a little bit more on each of the components. For example, if I click on some of these dots he can see is the lubrication oil filter We're rock around cover or a started my to Seoul annoyed, etcetera. So there's a lot of information on this engine. I will say at this point that if you go to the bonus section off this course, there are links to the interactive three D models in that section, you can watch the videos, but if you interact with Afridi models, you really are going to cement everything that you're learning in this course. In addition to that, they're also bonus video lectures on If you want to purchase more several courses, then there are some discount course coupons there as well. I definitely recommend checking out the three D models because even the quiz feature, such as that on display now click on the flywheel will help you learn the names off the components. I'm going to click here. Unfortunately, always correct that would have been very embarrassing if I got the answer wrong. We can see we get a little bit of information sometimes will be a picture here, sometimes to be a hyperlink to another three D model on. We can see our score on the right side of the screen so they're quizzes in built into the course, providing that you access to three D models. In addition to using three D models like that show. Now we're also going to use three D animations. So as you can see now, we're looking at a three D animation. But the big difference here is that the animation is fully interactive so we can spin around. We can look at it from all angles on. We're really going to get a very deep understanding of what exactly is happening inside the engine. Andi. Why it's occurring. So if you get the chance, check out Afridi models. Check out the animations, interact with them. If you've got a virtual reality headset, then you can also load the models in virtual reality. And I'm pretty sure if you do that and you watch these video lessons, you are going to learn a lot in a short amount of time. But enough about that. Let's get on with this very exciting course. The internal combustion engine is one of the most significant machines ever invented by mankind. It is completely revolutionised our world. If you're looking at a car, a van, a train, a ship, most likely it's going to be moved around by a combustion engine. The main design of combustion engine has not changed significantly in the past 100 years. The combustion engines were using today are only slightly more efficient than those of 100 years ago. But why is that what components are involved in order for us to make the combustion engine work? Why do we use different fuels like petrol or gasoline and diesel on? Why do we use different stroke engines like the two stroke on the four stroke? Well, let's start going through the course, and we're gonna get some answers to these interesting questions 3. Engine Exterior: so welcome to this lesson concerning the exterior parts often engine. Now, before we go too far into the course. I just want to clarify that when I talk about petrol, I'm actually referring to gasoline on the reason I say petrol is purely because I'm from the UK. I know a lot of people in the U. S and Canada will refer to as gasoline, and that's fine. But just because I'm used to say in the world petrol, I'm going to keep referring to that throughout the course. And if you want, you can just change that in your own mind with the word gasoline. When I mentioned system pressures and temperatures, I tend to work in Bath of pressure on Celsius for temperature. Where possible, I'll try to put some conversions on the screen if I do mention the pressures and temperatures because I know for some people they don't use metric units. They use imperial, so it's always nice to see a straight conversion rather than try enough to work with units that you don't understand. Now that's out of the way. Let's have a look at a three d engine. This particular engine is a four stroke diesel engine. Throughout the course, we're gonna be talking about the diesel engine only, and then I'm going to clarify on the differences between a petrol in a diesel engine and give you some examples concerning petrol engines. The reason that I want to stick to only one type of fuel, at least initially when we start the course, is because if we start mixing engines and we start changing between diesel and petrol, etcetera, it gets quite confusing. So let's stick to diesel just for now and at the end, I'll tell you some of the telltale signs you can look for to identify a petrol engine and also what some of the differences between petrol and diesel engines are. But let's stop there for a moment. Let's go and have a look at some engine components so we can see exactly what's happening inside an engine. And then after that, we'll look at the two stroke engine and the four stroke engine. I'll explain to you exactly how they work. By the time we've gone through that, you will definitely be in a position to look at this engine in a totally different light, and you'll understand exactly how and why is designed the way it is 4. Common Engine Components: No. Okay, so let's talk now about engine components. As you can see, there are quite a few engine components that make up an engine. We'll run through the main ones now, but will only cover the components that are common to both four on two stroke engines. Let's start at the top, the most iconic symbol. Often engine is the piston, and we can see the piston. Here. The piston itself travels up and down linearly within the cylinder liner that is this section here. It's called the Cylinder liner, simply because it's cylinder shaped. The cylinder liner within a normal engine is slightly more complicated than that currently show. And we can have a look. A true cylinder, Lina. A little bit later. So we ever piston. But Piston itself connects to a connecting rod. That is, this item here on the connecting rod connects to a crankshaft. The crankshaft is this squiggly shape that we're looking at now. He runs from left of rights, and, as you can see here, from the right side to the left, is a straight line. Although the shaft itself is not straight a total, it actually travels up and down and up and down. The reason for this is that as the piston moves up and down, the crankshaft actually rotates. Don't worry too much about that right now. We're gonna have a look at the animation in a moment. Those are the main items that are common to four and two stroke engines. What I'll do right now is quickly load up a model of a piston assembly because I want to show you exactly this piece in a bit more detail so that you can see exactly how it connects to the crankshaft. So here we are. We're now looking at the piston and connecting rod again. But we've exploded it out into all of its components. Play the animation. You can actually see it being assembled. I need to see their quite few parts involved. We're not going to go into great detail concerning all of these parts, but we are going to look at the complete component as a whole and try to understand exactly what it does so we can see we've got the piston top here. See, we got the connecting rod. In fact, let's just explode out so we can see everything. So here is our piston Here is ah, connecting road. We actually have some bearings. These are what they call plain metal bearings here. And these bearings are the only thing separating the connecting road from the crankshaft. The reason that we have the bearings is because when we clamp all this together, you just reassemble it. He's going to clamp onto the crankshaft here, but we want the bearings to allow the cranks after rotate. But the connecting rod itself is only gonna move up and down and around with the crankshaft . It's not gonna rotate to the same degree that the crankshaft is going to rotate, and that's the purpose off having these plain metal bearings. So that is essentially piston assembly. Let's go back and have a look at the other model now, and we can watch the entire thing working and then we'll have a look at the two stroke in the four stroke cycle. So here we are. We're looking at a piston connecting rod, also known as a Conrad, so don't be thrown off by that and a crankshaft. Several away clamps onto the crankshaft. See, there's the bolt here. There's another one on the other side, so we're gonna tighten that up, clamps onto the crankshaft on. Then what's going to happen is as the piston moves up and down within the cylinder liner, the crankshaft itself is going to rotate. Let's see that happen, because it's a lot easier to see it rather than explain it. And there we go. The piston travels down in a linear, that is to say, a straight line motion. He then travels up, and the cramp chef continues to rotate. So we're changing the linear motion that's occurring in this area for rotary motion that's occurring. Where the crankshaft is, as you can see, is also a lot of action that's occurring at the top of the cylinder liner. These items here are valves on. The vows will open and close at specific times during the combustion cycle. Now, I don't want to talk about those at the moment because the idea with this lesson was to simply discussed some of the main components that are common to both the two stroke engine on the four stroke engine and even the steam engine. Now they set up off piston Conrad Crankshaft is used a lot for our engineering anyway, not just for four stroke, two stroke engines and steam engines. But you can also use it for positive displacement pumps. If we did so, then we'd actually refer to this as being a piston pump. Let's go Never look now at exactly how a two stroke engine works because it's a much simpler design on a four stroke engine. 5. How Two Stroke Engines Work: So here we are now we're looking at a two stroke engine. Notice that we have the same parts is before we got a piston connecting rod and crankshaft . The area surrounding the crankshaft is known as the crankcase. So that is this section around here. You can see we've got some labels here. Makes it a little bit easier to understand what's going on. Got air and fuel Fuel is usually indicated with an orange or and the color for our purposes reviews blue as air. The reason that we have half of the Arab blue and half of it orange is because we've actually got an air fuel mixture. That means that the fuel is mixed in with the air. I'll explain to you how that works in a moment on here we have exhaust guess indicated by a black arrow. So what's happening? Let's play the animation a moment again. You see the piston moving down and we're gonna see it moving back up in a moment. The crankshaft is rotating on their arrows, popping up every now and again to show us what's occurring. This is a two stroke engine, so let me walk you through exactly how it works. Two stroke and four stroke engines are internal combustion engines. That is because combustion occurs internally inside the engine. It actually occurs within the cylinder liner. That is this space here, and we also refer to it as the combustion space. In order to have combustion, we need three things. Oxygen, heat and fuel. These three things are used to make a fire triangle. But where we gonna get the oxygen from? Well, we get the oxygen from outside the engine, specifically just ambient air. We can draw the oxygen in with the air through this space here, this is known as our inlet port. We can see now to the air is rushing in, and we have some fuel that is mixed with the air. So we'll mix of fuel in with the air before it comes into the crank case. Now, I know we said we're gonna be talking about these legends early on the course, but I want to mention here One important thing the type of fuel used with two stroke engines is almost always petrol. It's highly unlikely that you're ever going to encounter a two stroke engine that uses diesel the only time I've ever seen this is on very large container ships, oil tankers, very large ships. They will use diesel fired two stroke engines. So if you want to take a very general approach, just say two stroke engines are pectoral fired only. So the fuel is mixed in with the air. It is drawn into the crankcase. It flows into the crankcase on. Then it is going to sit within the crankcase space. But we can see that there is another transfer port over here. So we have that in LePore. We can get the air in the fuel coming in, fill out the crankcase, and then it's going to travel out of our transfer ports is gonna come up here. And then it's coming into this section here. So it's coming into a cylinder, Lina. Notice over. We're not going to get the air and fuel up into the combustion space because the piston is blocking that. So let's see what happens when the piston comes down. The feasting comes down and it covers up the air on fuel inlet. So we're no longer going to get air if you're coming into the crankcase. And when the piston travel down. It's actually compressing the air fuel mixture in the crankcase, and it's squeezing it out off the transfer ports. See, it's coming up here just round about here. It's starting to escape into the combustion space, so it's coming into the ceiling. The liner. As the piston continues downwards, it's going to reach the bottom of its transit. And that's the point we actually call a bottom dead center. We just highlight that because that is a very common term that you should definitely get to grips with. Let me just show you that again. Piston coming down, Shut off the air fuel mixture or the air inlet. Poor bottom Dead center. The piston does not travel any closer to the crankshaft than where it is now, so we'll call that bottom. Dead center will be D. C. The opposite of BDC is TDC, which is top dead center. You can play that again. Let's just have a quick look because we can see top that center as well. The piston is as far away from the crankshaft as possible. That is top dead center. So now we know those times. Let's try it again. Here's the piston coming down. We're heading towards bottom dead center, a boy's animation, and now you can see that the transfer port is completely uncovered. The Pistons gone all the way down. It's compressed the air fuel mixture in crankcase. It's essentially squeezed that out into the cylinder liner, and now the piston's gonna come back up again. So now we've got our air on fuel on. The thing that we need now is a source off ignition. So remember the fire triangle, air, fuel on heat, all of things we need for combustion. I should actually say specifically here. We need the oxygen that is contained within the air for combustion. So not just the air itself. So perhaps I should call that oxygen, heat and fuel. But we've got the oxygen which is contained in the air. We've got the fuel because we just drew all of that in through the transfer poor. And now, if we compress Aled that whenever you compress a gas, its temperature increases as its volume decreases. Not only that, but as you compress the gas, it's pressure will increase as well. So I just remember that compressing a gas pressure increases temperature increases, volume decreases. And then when we get to top that center roundabout here, we're going to use a spark plug that is the site in here to create a spark. In fact, we may even see that can see it here. We're creating a spark, and we are going to ignite that air fuel mixture. So now we're gonna burn the fuel in the oxygen in the air. We have everything we need for combustion, oxygen, he and fuel. And we even have a source off ignition. So the spark from the spark plug ignites the fuel within the air fuel mixture. Remember, it's very hot in here. Now we've got quite a high pressure as well. We get a controlled explosion on we get combustion on because this is happening internally . We have internal combustion. In other words, an internal combustion engine. He's a large explosion. When we have that large explosion, we back it up slightly. Explosion, huge increasing pressure. Huge increase in temperature on we're gonna force that piston downwards as the piston goes downwards or travels towards the crankshaft, we're going to uncover an exhaust gas discharge port. That is the sporty can see now we're discharging the exhaust gas. The reason we're discharging the exhaust gas is because we've burned all of the fuel on. We've taken all of that chemical energy and were turned into mechanical energy, which is rotating the crankshaft. So within a very short space of time, we've managed to transfer that energy to the crankshaft. We'll get rid of you exhaust gas that would just come out of our exhaust gas manifold or tailpipe on the process is ready to repeat. Just see that happening again. Piston comes down and we can already see. We are now allowing air and fuel into the combustion space again. And we can compress all that. And as it moves upwards, we're going to cover up the transfer poor. If we zoom in here, you can actually see that a little bit later. Recover up the exhaust gas poor. Normally, the exhaust gas sport would be slightly lower down, so we don't get too much waste. Specifically, Aaron fuel That's discharged out the exhaust gas poor when he shouldn't bay. But now the remainder of the air and fuel will again be compressed. We'll get ignition, Andi. Then the pistol will move back down again. Now we talked about bottom dead center in top dead centre. Let me introduce you to a couple of other terms. The reason this engine is called a two stroke engine is because whenever the piston travels from top dead, centre to bottom dead center, just do that right now that is referred to as one stroke when we travel from bottom dead center to top dead center that is referred to also is a stroke. So whenever we go from T D. C to BBC or BT seats, TDC, we complete one stroke. Now you may have noticed that we complete an entire combustion cycle in two strokes. The piston went down and then up, and then we repeated the cycle again. All internal combustion engines contained four main parts to each of their combustion cycles. Let's go through each of those parts right now. The father in now or coming up to he's known as suction, sometimes referred to his intake. If we zoom in, we can see that we're drawing here into the combustion space, so we'll call that our intake or suction part off the cycle that is stage one. Once we have sucked in the air on the fuel we go to our next stage, which is compression. We're now compressing the air in the fuel that is staged to once we get to top dead center , we get are controlled explosion. We start the power part of the combustion cycle. Finally, we uncover the exhaust gas port on we get to the exhaust stage of the combustion cycle, So suction, compression, ignition, exhaust, suction, compression, ignition, exhaust. You can also say suction compression power exhausts or intake compression power exhaust. Whatever you want to say. Those are the four stages that make up every internal combustion engine cycle. The only difference during the two stroke in a four stroke engine is that a four stroke engine uses one stroke. Her part off the cycle on a two strike engine does no. So let's go through it. Suction, compression, ignition, exhaust. And we can repeat that. We can even speed it up, and that is essentially what is happening within a two stroke engine. The reason that two stroke engines are only used for small engines is simply because they're not as efficient as four stroke engines. They have only half of the strokes, and that's true. That could be seen is a good thing because we want toe repeat the combustion cycle as much as possible. Unfortunately, they actually waste quite a lot off air and fuel, especially during this changeover period when the piston covers up the air and fuel inlet and then later covers up the exhaust discharge outlet. So we have a bit of a loss there, with the air and fuel traveling out of the exhaust port. But the power stroke itself is also incredibly small. We look here ignition expansion exhaust. The power stroke is very small. It is literally only let's go back up, stopped at center. Here it comes. A power strike is more or less from this point where my mouse is now down to here. As soon as we uncover the exhaust gas port, the pressure in the combustion space drops dramatically on. Essentially, we've extracted as much energy out of the power stroke as we're going to get with four stroke engines. It's possible to make the power stroke a lot longer, and you can also time when air and fuel is let into the combustion space much more precisely, and when exhaust gas is let out of the combustion space, so all of these factors make the four stroke engine mawr efficient than the two stroke engine. This is despite the fact that the four stroke requires twice as many strokes for combustion cycle and four stroke engines have many more components compared to a two stroke engine. So I hope you now know how a two stroke engine works. Let's no go. Another look at how a four stroke engine works. 6. How Four Stroke Engines Work: So now we're looking at a four stroke combustion engine. And as you can see, there are more parts associate ID with this type of engine than for the two stroke engine. Despite this thesis, suction, compression, ignition, exhaust, part of the combustion cycle that has not changed. Let's go through that right now they will look at some of the new components in greater detail. So let's push play. The piston is moving downwards on. At this point, we're drawing air into the combustion chamber. Izumi, we can see that we have two valves. That's these two items here and they are open. Be back out. The moment the piston travels down the valves open on we draw Aaron to the combustion space June back out a little bit. Could see that at some point, the piston is going to reach bottom Dead center. The valves are now closed on the piston's gonna travel linearly back up again. So we reached bottom Dead center. We can see that because the crank shaft is rotated all the way down Words here. So the beast on now is gonna return to top that center. Just angle this correctly. We're going to compress the air. But notice this time I said air. I didn't say air fuel mixture just said air. The combustion space is full of air only. How is a? If we look very close to here, we can see that fuel is being injected into the combustion space. This is actually a fuel nozzle here, and we're using the fuel nozzle to spray fuel. Is that no? So into the combustion space. Zoom out again. So we got our injector, which is spraying fuel into the combustion space. We've got our oxygen which is contained in the air. Let's compress all of that. We'll get an increase in pressure, an increase in temperature and now our fuel is going to combust. So there we are. Top that center. We have a controlled explosion that's indicated here by this red color. And then we'll get a massive increase in pressure and temperature. We're gonna force that piston back down. The cylinder liner goes away to bottom dead center. And at this point, we're going to start to travel back up. Let's play again and you can see that the other two vows have opened. Those are exhaust gas vowels. So they're allowing the exhaust gas to exit out of the combustion space on the piston itself as it's moving up, is pushing that exhaust gas out. Once we've completely removed the exhaust gas, it's time to repeat the cycle again. So let's go down and we can count the number of strokes. Suction, drawing Aaron opening up the air intake valves, compression, compressing the air, fuel injection, ignition, power stroke. And then we will force the exhaust gas out of the combustion space on the cycle repeats. So straight. One suction straight to compression, straight free power and then straight for exhaust. If I'm honest when I am teaching, I actually prefer the four stroke engine because it's quite easy to understand exactly what's happening. Piston comes down, draws Aaron. We compress it. Inject fuel ignites controlled explosion, expansion, power stroke on, then exhaust. If you can't remember all that, just remember. Suck, squeeze, bang, blow, suck, squeeze, bang, blow Facts for speed off slightly. Maybe I can Dear suck, squeeze, bang, blow, suck, squeeze, bang, blow on etcetera. So that is essentially how a four stroke engine works, so the combustion cycle is the same. But the number of strokes is different on. Also how we let the air into the combustion chamber is different on how we get the exhaust gas out. This type off engine may be either a diesel engine or a petrol engine. It's not totally unusual to have a petrol engine where the fuel is injected into the combustion space. There are four main methods off delivering fuel to the combustion space for petrol engines . One of them is in the poor. I believe one is sequential on day one here is direct and there is one other as well. The reason that this is not a petrol engine is because we have no spark plug. There is only a fuel injector that signifies that this is a diesel engine. So if you ever looking at engines and you find spark plugs, you'll know immediately that it's a petrol engine. This type of engine that is the type that uses diesel fuel is known as a compression ignition engine, because when we compress the air, we get the increase in temperature we need in order to get combustion. That's not the same four petrol engines when we compress the air for petrol engines, even when we had the fuel. We need to ensure that there is efficient combustion on in order to have this. What we actually need is a spark plug, so we're supplying the source off ignition. For this reason, diesel engines are called compression ignition engines on petrol engines are called Spark Ignition engines. Let's have a look at the valves and how they open and close, and also we can have a look at the fuel injector. We'll do the fuel injector first because it's relatively basic can see on the opposite side . Got a connection here. The connection connects to a fuel injector and, as the name implies, were injecting fuel into the combustion space Could see. It's got quite a pointy shape. It goes all the way down into the combustion space. We'll inject the fuel into the combustion space through spray nozzle. If we're being very precise here, we might even see tiny dots on the spray nozzle. Body doesn't like it, so there will be tiny dots here, right on the tip off the nozzle, and the fuel will be injected into the combustion space on it will be vaporised. It's going to be like a fuel cloud. That means it has very good contact with the air. And that means we're going to get very efficient combustion. If we injected just a few drops of fuel, those drops are not gonna have very good contact with all of the air. So we're not gonna get efficient combustion. So we've a prize, the fuel, We make it into a diesel cloud. And that means we have very good contact between the fuel on the air. So we get very efficient combustion. Now we've got to air inlet valves and to exhaust valves. At the moment, we just starting a suction stroke. The air valves are open. But how? Well, in order to ensure that the entire engine is time correctly, we need a camshaft. She's a camshaft. Here. The camp shaft is used to open and close the air inlet valves open and close the exhaust gas vowels and sometimes also to control when fuel is injected into the engine. Now the camshaft is usually connected to the crankshaft on we will use a chain or a gear to connect the crankshaft to the camp chef directly. The reason we do this is because we want the camshaft to remain in sync with the crankshaft . So as the crankshaft rotates, it's also going to drive the gears or a chain, and it's gonna make the camp chef rotate as well. The response will. The rotation of the camp theft is directly proportional to how much the crankshaft rotates . Well, actually, gear the camshaft so they eat completes one full revolution every time the crankshaft completes two revolutions. So let's take. This is an example. This black item here is called a cam lobe. You can also call this a camp. It's pointing more or less upwards. We can see here that the crankshaft appears to be pointing a little bit off to the right. If we're basing that on this section here, so it's coming along. Now. Crankshaft is rotating. Don't half a turn. We've done one complete turn, and you can see now the lobe is pointing downwards. So 280 degrees that that camp shaft is rotated. Crank shaft is rotated 360 degrees, so there's a 2 to 1 gear ratio. Let's let it continue. Crack separate states again. It's coming back around now. Number 90 degrees, and we'll get around to start position. So we've completed two full rotations on the crankshaft, 720 degrees on only one on the camshaft. But in this way we can control when and how the valves open and close. The gearing is important because if we were to Max Irritation the camp chef to the crank chef, the engine wouldn't work. Let's see what the camshaft is doing. Well, taken example is our low concedes, pushing this item up this long stick. This is known as a push rod. It's coming up here to what we call the rock Karam. It's causing the rock around. We pushed down. That's pressing down upon this section here. That's the top of our valves. Go down. We got two valves on the vows. They're open. We back it up the moment. So the violence here it closed. Lo comes around, pushes to push right up because we pushed the push right up. We actually caused the rock around, pushed down onto the top of the valves. See that again? Push two. Push right up. Push the top of the vowels down. The vials are now open because they've been pushed down. And if we go down again, we can see a cam lobe is going to continue to rotate. Now the push rods is dropping back down again. That means our rock around is returning to its position on the things that are making the rock around. Return to its position. Are the valve springs the's shiny items here. His one is another is one the back, another one there. Those of our springs springs are residual stressed items. In other words, if we place them under compression, they want to expand due to the residual stress they contain, also known as tense or force. So if we back up again, I can see there would compressing the springs. And as soon as the cam lobe is no longer pushing the push right up springs, return the valve back to the closed position. Can see that here. The valves have completely seated now, and they have stopped air traveling into the combustion space. Now the exhaust gas valves are pretty much the same. Same design, same components, same mechanism for opening and closing. If we wanted, we could actually go down here, and we could use the push ride in the back and we could watch the entire process repeat again, but we're not going to do that. And the reason we're not going to do that is because there's one area that I want to show you first, which is slightly more interesting in order that we get Mawr Air into the combustion space and to ensure we flush out all of the exhaust gas, we're actually going to make the air inlet valves bigger than the exhaust gas valves. You come here to see it so much here, let me just see if I can get some sort of valve overlap. This is that power stroke exhaust gas valves are open. The pistol must be traveling up. It's forcing the exhaust gas out. What would actually have at this point is a little bit of crossover known as valve overlap , where the air inlet valves open slightly on their allow Aaron and that ensures that we're flushing all of the exhaust gas out. We don't seem to have any overlap on this particular freely model, so that's slightly inaccurate. But imagine for a moment we had a slight opening of the Air Inlet valves. Let's say right about now that is going rushing will flush out all of the exhaust gas. And that ensures that all of the exhaust gas has been removed from the combustion space. Or as much as possible. Which means we are completely filling up the combustion space with new fresh air fresh oxygen, which we can use for combustion. There's no point having a little bit of exhaust gas hanging around in this section. Let's imagine for a moment the exhaust gas valves closed, the air inlet valves open, but this space here is still full off exhaust gas. So when we open the Air Inlet valve, we have no flushed out the exhaust gas that's in the combustion space. So that's why we have valve overlap, a point at which the air inlet valves and the exhaust gas fouls are all open at the same time. So that is how a four stroke engine works. There are variations and slightly different designs, especially if we're using different types off fuel. But essentially the strokes involved with the combustion cycle that is suck squeeze, bang blow. There are always going to be the same. I hope you now know how a four stroke combustion engine works. Let's go Never look now at some of the differences between petrol and diesel engines, 7. Petrol vs Diesel: So let's now have a look at some of the differences between a petrol engine on a diesel engine. Now I've loaded up another three D model, and you can see this one's got some markings and indications on it. We'll load up the annotations so that we can actually click on. Each of these markings will get a bit of a description on. We can sort of read our way through some of the terms, so we have our own irritations. This model is also available online, so check the resources section of the course or just head over several dot com. Click. Here we could see things such as the clearance volume cylinder bore and things like that. I strongly recommend that you load up this really model yourself and check it out. It's especially useful if you want to learn some terminology, but the areas were interested in a violent our number eight, which is clearance volume. That's the distance from top dead center to the top off the cylinder liner. In other words, if the piston travels up to this height here, the clearance value is from top Dead Centre, the top side of the piston up to the top side off the cylinder, Lina. So that is known as clearance volume. We have a look over here. Number 14 this is the stroke. This is the difference between TDC and BBC. But we also refer to that as a swept volume. You say swept volume because area is, for example, sent to me. Two squared me two squared inches squared. If you are working with imperial measurements and it to calculate volume, we take the area that we multiply it by the length. Now the left in our example here is simply the distance between BBC and TDC. So we'll call that swept volume. That is the volume the piston is sweeping as it moves upwards. The reason that I'm highlighting the clearance volume and swept volume is because when we compare them together, we end up with something called the compression ratio. The compressive ratio is a sweat volume plus the clearance volume. So that is essentially this total volume within the combustion space. And then we divide it by the clearance volume now looking just, for example, that swept volume here we can see that the sweat value is perhaps 10 12 times bigger than the clearance volume. That's just an approximate guess, Let's say 12 times bigger, So a compression ratio here is 12 to 1. One of the differences between petrol and diesel engines is the petrol engines have quite a small compression ratio compared to diesel engines. Petrol engines will have a compression ratio between about 7 to 12 to one. Diesel engines have a compression ratio between about 13 or 14 to 1 up to 25 to 1. Now 25 to 1 is a very large compression ratio. So let's just say, for arguments sake, the petrol engines have a compression ratio of about 8 to 1, and these legends have a compression ratio of about 16 to 1. So these lame gyms have a compression ratio, which is double that of petrol engines. That's not always true, but let's just keep hours of rough approximation that makes the diesel engine more efficient. The power stroke is longer in a diesel engine, comparatively compared to a petrol engine. Not only that, but the pressure reached within the combustion chamber because of this increase in the compression ratio, the pressure reached at the top as the piston approaches TDC is far greater than that that could be achieved in a petrol engine. This is also an aspect of what makes a diesel engine more efficient. If you start with a higher pressure shortly before the power stroke, then you have mawr pressure energy that you can turn into mechanical energy. And that's exactly what these range it does. Because we have a higher pressure within the combustion chamber of a diesel engine, all of the parts of a diesel engine will need to be slightly larger than that of a petrol engine. This is one of the reasons why diesel engines a heavier on, also, why they're quite clunky. If you listen to a diesel engine, you'll hear that it's actually a little bit louder than a petrol engine, and it also just sounds a little bit slower. The policies from the exhaust gas manifold or the tailpipe slightly louder and a little bit easier to identify. So next time you pass a car or a truck, have a listen and see if you can identify the type of engine that's installed. I can guarantee you they do sound very different. Another difference between petrol and diesel engines and some people would argue this point is that diesel engines tend to smell a little bit more than petrol engines now. I never really believed people so much when they said this. They're always saying our diesel stinks spectral not so much, but I can say, after living in the city for almost 10 years, that diesel does stink. Not a petrol is particularly so much better. But in my opinion, burnt diesel does give off a stronger smell than but petrol again, people would argue this point on the final difference. That's easy to identify between a diesel and petrol engine is simply a diesel engine does not have spark plugs. Remember, diesel engines are compression ignition engines. Petrol engines are spark ignition engines. They require a spark plug. It's the heat in a compression ignition engine that causes the fuel to ignite. Whereas for petrol engine, it's a spark that causes the fuel to ignite. So if you see spark plugs, you'll know immediately it's a petrol engine. Another difference that you may notice is the position off where the fuel is injected. Now, I say May, because some petrol engines inject fuel directly into the cylinder liner, and they look quite similar to a diesel engine. Except it will have sparked clocks, So check the position off the injectors as well. If the fuel is being injected not directly into the combustion space, it will not be a diesel engine. Diesel engines always inject the fuel into the combustion space directly. The petrol engines. This is more of an option rather than a certainty. Another slight giveaway with diesel engines is that many of them are turbo charged. That allows us to get more air into the combustion space. But not all these engines are turbocharged. We can have a look a turbocharger a little bit later in the course. So now you know some of the differences between a petrol on a diesel engine. Let's go and have a look now at what I refer to as the life support systems, often engine 8. Lubrication Oil System: so welcome to the first lesson in what I call life support systems. These air the systems and engine EADS in order to survive. Now there are six main systems that you're likely to encounter when you're looking at internal combustion engines. These are oil fuel, water, air exhausts on the electrical system. Some engines have more than six systems, and some engines have less lubrication, oil, fuel, air and exhaust. Those systems are always going to be present to some degree, sometimes for very small engines. You'll actually mixed lubrication oil in with the fuel itself, although that is only for very small two stroke engines. So let's look at the lubrication system first, because arguably, it's the most important system in the engine. I've loaded this Freedy model up. It actually shows the lubrication all system, and it's highlighted. With these orange colors. You can see that lubrication oil is pumped all around the engine. It actually sits in the base off the engine. Here, this is what we call the oil pan or the world reservoir within usual tongue, that is. Besides him here on your pump will pump the oil around the engine. You can normally see the oil pressure on this section. Here we have an oil filter that is represented by this filter strapped onto the side of the engine, and that will filter out any impurities that are within the oil bits off metal bits of sand . But dirt, anything that might be in your that we don't really want to be circulating around the engine. Now you might wonder. Where are these bits of metal coming from? Well, they're always going to be present very small shavings, sometimes from bearings and other engine components. And if you're cleaning an oil filter, you'll notice them because they feel a little bit like sand or grit. When you rub your fingers together on those BC's air just essentially bits of metal or bits of sand, dirt and things like that. So we want to filter those out. Because if we circulate them all around the engine, what will actually be doing is pumping these bits of sand on metal into places such as between the bearing and the crankshaft, where they're gonna cause damage. The clearances between the bearings on the other machinery components in the engine are very, very small. So anything that gets into these spaces is most likely going to damage the metal. Sometimes you'll actually flake off a bit of a bearing, for example, and then that falls into your system as well. And it's a cumulative effect. So that's what we have oil filter We can actually see on this engine that we have some gearing here. Associate ID with the camshaft looks like it's geared and hooked up also to the crankshaft on the oil pump. The oil pump is driven from the crankshaft itself as well. But what we're mostly interested in for this lesson, rather than go for an analyzed the entire lubrication oil system, is the fact that the all itself is responsible for cooling Andi lubrication. We send the oil to allow the areas of the engine that move. In other words, if the rocker arms are moving up and down there pivoting, you can see we're going to need to supply oil into this area in the rock Karam and we're gonna press you all our all around this inside of the ring so that when they operate, let's just see that occurring. Maybe we can conceal one in the background there, spinning if that was spinning on a metal surface directly, would have a lot of friction on a lot of heat. So in order to get around this, we actually lubricate the inside. And that reduces the resistance of friction, which means we generate less heat with all of this movement. What you have to understand, though, is that the rocker arms are the least of our worries. He's a relatively lightly loaded on. They're not going to generate a huge amount off friction. However, when we get down and we start looking up the pistons the crankshaft camshaft, you can see the crankshaft rotating. Right now, they all need to be lubricated because if not, the engine will overheat very, very quickly. And when it does, you run the risk of having thermal expansion. That means the components A will get larger due to this increase in temperature on the engine may store. And if that happens, then you have to wait for the engines cooled down again. Before you can operate the Engy, we actually call this seizure, or sometimes you hear people say that the engine has seized, so there are two main purposes off lubrication oil, one to lubricate and reduce friction on two to remove heat, the oil returns back to the oil pan will do all reservoir in the base of the engine. And there it's going to be called. Imagine for a moment that this engine was attached to a truck you can see on the bottom. Here we have these squiggly shapes all along here they allow heat to be transferred to the air very efficiently. So if this engine was mounted in a truck and the truck was traveling forward, such as in the direction we're traveling now, then the air is gonna be passing across these fins, these cooling fins on. We're going to be cooling down all of the oil in the oil pan. If we do that, then that means that your temperature will reduce on when we re circulated around the engine again. We're not gonna cause the engine to overheat. Obviously, if we slow the engine down, it means we're not travelling as fast anymore in a van, which means we're not getting as much air passing over these cooling fins. But that makes sense because we're not normally going to sit and rev the engine for half an hour and not actually move the vehicle. So when the engine is working harder, there's more air passing over the oil pan and cooling down the oil on when the engine is not working as hard, there is less air passing over the oil pan and cooling the oil. But then the oil is not as hot because the engines not working as hard, so it's almost like a proportional response. The faster and harder the engine works, the more the vehicle is gonna move on them or air that can be used to cool down the oil within the or pan. When you start looking at larger sized engines, you won't rely on air to cool down the oil any longer. The heat generated by the engine is simply too much. There's too much oil to cool down, and it's not efficient any longer to call the oil using air. So what you're uses an alternative system such as water and you'll have a totally separate system for that on the water would be pumped around this system and it will pass for a series of tubes maybe, and the or will pass around the outside of tubes on, we will call the all in that manner. Obviously, it's very important to ensure that the water doesn't make through the oil because of it did . That would be a big problem for the engine itself, because water itself does not have very good lubrication properties. So the purpose of the lubrication all system to lubricate Andi to cool, smaller to strike engines do not have a separately educational system simply because there are too many parts involved and increases the weight of the engine by quite a lot. So rather than having a separately educational system or your electricity's that the lubrication oil is mixed in with the fuel itself. If you have ever owned and operated a small two stroke engine lawnmower or a leaf blower or anything like that, you'll know that sometimes they tell you to add one partner educational to 100 parts off fuel oil or one partner educational to 50 parts fuel oil. It really depends on the age off the engine, so you're mixing the lubrication oil in with the fuel. As I've said that once you get to larger engines that simply no longer possible, you need a separately educational system. And when the engine becomes even larger than you're going to need a separate system to cool down the lubrication or itself. So that's the first system out of the way. Let's go and have a look now at the fuel system. 9. Fuel System: okay for the fuel system itself is not so much that I can show you. Normally you'll have a fuel pump. You'll have some injectors or some means of delivering the fuel to the combustion space. But what you'll always see our fuel filters. That may be one of these here. I'm guessing it's the one on the left or actually could be this one right, cause the fuel filter is normally smaller than the lubrication oil filter, but anyway, you'll see a filter. Sometimes it's quite small. It'll be on the underside of your car between the fuel tank on the engine itself. And if we go on the top of the same gene, maybe I would see the fuel injectors can see. There is a fuel injector here on a fuel injector connects into a combustion space, which we saw a little bit earlier. Fuel, maybe diesel or petrol slash gasoline. But there are also gas fired engines as well. And theoretically, I suppose there's no reason why you can use pulverized coal dust. I believe that's originally what internal combustion engines were fired on for. The fuel system itself does not so much I can show you using three D models. But what I can tell you is that normally you'll have a fuel tank, a fuel pump on a filter. Perhaps you're sometimes have to filters primary and a secondary filter, and you have a means off delivering the fuel to the combustion space. And that will be Vyron injector or by some other means, such as mixing the fuel in with the air. Sometimes injection off fuel into the combustion space will be done mechanically. You'll use a very similar set up to that which we saw earlier when you were opening and closing Exhaust gas valves or air inlet valves. But you'll have something different. It comes off camshaft, and that will be for opening and closing the fuel injectors. Many modern engines use a completely electronic control system two time when injection occurs in the engine. That's simply to increase the engine efficiency a little bit well, that the downside here is that any problems you have with the Elektronik side off the engine will render the engine more or less inoperable because if you can't time the injection and control when the valves open and close etcetera, the engine simply won't work That's one of the big weaknesses of modern engines. They're so heavily reliant upon electrical systems. Personally, if I had the choice of for a totally mechanical engine, they just run on run. They never stop. They're very, very reliable. But the downside is they are slightly less efficient on very modern high tech engines. Let's load a three d model it now so we can look at the air system. 10. Air and Exhaust Systems: Okay. So to look at the air system, what you want to do is give you a bit of a case study on an example. Really speaking, If you want Teoh talk about the air system, I suppose we could just say yeah, has to get to the combustion chamber because we need the oxygen from the air. And then after that, it gets burned on turns into exhaust. Guess so. That's very much it. You need to get here to the combustion chamber, and that's its job. Then finished. Let's have a look at working example, though, for this particular freedom model, we're going to have a look at an engine with a turbocharger, and turbo charge is quite common on diesel engines. So let me run you through the system quickly on. Then we'll run through in a bit more detail afterwards. So here is our very charger. It's got this snail like shape come around here. See from this angle, see very unique shape. It's quite a lot happening here. Blue signifies air was sucking air into the turbocharger because the turbocharger is actually rotating, and I'll explain to you how that works in a moment We sat there in through what we call a compressor or compress a wheel on. We compress the air and then we force around this snail shape called of veloute. So the snail shape is called a veloute casing and we're actually doing there is we're changing the velocity off the air and converting it to pressure energy. So from kinetic energy to pressure energy So we've increased the pressure off the air. No expansion while we do that in a moment as well. Yeah, it comes along down here, it's gonna come along here and then we go into an air Kula. We call the air down slightly, We send it then to the combustion chamber. See, from the top comes off, goes to, uh, Aaron, the valves they open on the areas forced in because the pressure off the air within the air inlet manifold is higher than in the combustion space. And that's what allows the air to flood in. When we get a little bit of valve overlap so some of it flows out the exhaust gas, pour flush the bit of exhaust gas out on, then our system is finished. To completely understand the model, though let's follow the exhaust gas system. So we have to to exhaust gas valves coming out here. Does gas comes along, then rather bizarrely Come along. They're coming down here. Exhaust gas connects onto the turbocharger. So is the exhaust gas manifold, and it joins onto the turbocharger, goes around and then exits out off the turbocharger turbine. So that's quite interesting. What we would do that. Well, let's have a look. A system in greater detail. When the exhaust gas comes out, it's gonna pass over this turbine, and he's gonna cause a turbine to rotate. When the turbine rotates. It's actually on a common shaft, so that's come along here. Conceits on the same line as the compressor will becoming along the shaft runs through the middle, so when the turbine rotates, the compressor wheel rotates. That means theme, or the turbine rotates the mawr. The compressive wheel rotates. Imagine you had two wheels connect you on a common shaft. Now, if you spin one wheel, the other wheels going to spin as well. And that's exactly what's happening here. So we're drawing more Arian because the turbine is going faster. We compress the air on when we compress it, the temperature increases. Remember we said earlier, if you compress a gas, the temperature increases, as does the pressure. Because we increased the temperature we take the air on. We cool it down. We call it down because the more we call it down the mawr air, we can get into the combustion space, which means we have more oxygen available for combustion. That's the purpose in this whole turbocharger set up. We want to compress the air so we could get more of it into the combustion space. And we want to cool the air once again so we can get more of it into the combustion space. The air comes out and then it goes to the combustion space on. After that, we get the exhaust gas. L see. If we can learn this up, better exhaust gas comes out and goes back to the turbocharger. Now, if you've ever heard of a concept called turbo lag, the reason we have turbo lag is because it takes a while to get more air to the engine. And then it takes the world to get more hot. Exhaust gas to the turbine turbocharged engines take a while to Billy a second or two to really get into motion and to get the turbine rotating very quickly on until that turbine is rotating very quickly. We can't suck more air into the compressor wheel, which means we don't have the oxygen available in order to release more power. So that's towboat lack. The other thing that you're going to see on all engines normally is an air filter. Fills is a big part of engineering. You install them because you want to remove particles from a system or prevent them entering a system in the first place. Now we don't want to suck just normal ambient air into our engine. The my bits of dust floating around a might bit of sawdust. Who knows? Imagine you drove past a wood chip ings factory or some other sort of factory. All of that dust in the air will get sucked into your engine unless you have a filter. If you have a filter, you'd install it shortly before the turbocharger, and this means that I should draw air into the system. It's gonna be filtered on. We end up with clean air going into the engine. If the engine doesn't have a turbocharger. Then you'll install the air filter simply on the main air inlet, and you have to change this bill to periodically the same as with the lube oil filter, which is a lubrication oil filter on day fuel filter. So I feel it is very important if you want to own and operate your engine for a very long period of time. Now it's going to a separate video for the absorbs gas system, but I don't think that's really required. The exhaust gas system will usually be at least on medium sized engines. Simply an exhaust gas system like that show, especially for medium sized easels on it, will go to the turbocharger on. Then maybe it passes through some sort of noise reduction apparatus or component, sometimes calls a silencer or a muffler. And this means that we're not creating a lot of noise with our exhaust gas system. When it comes out of do tours, gas pipe on engines that don't have it overcharge up, then you can discharge the exhaust gas directly to atmosphere. Important to realize, though, that the larger the engineers the more complicated the exhaust gas system will become if you have an exhaust gas system with a very large fees ranging the exhaust gas may have to be cleaned before is discharge to atmosphere, that's just modern common practice. You can't just dump exhaust gas into the atmosphere like we used to do 100 years ago. So in order to comply with environmental pollution legislation and laws, you sometimes have to clean the exhaust gas, which means taking the burnt carbon out of the air, for example, before you discharge to atmosphere. But anyway, I hope you now understand how the air system works and some of the components you're likely to encounter on. You also understand exactly how the exhaust gas system works there really to be simple systems. But as with many things in engineering, the bigger the system becomes more complicated, it becomes and the more complicated all the components become. So we cover four systems. Let's go and have a look now at the cooling water system 11. Cooling Water System (Jacket Water System): So let's have a look now at the cooling water system also sometimes referred to as the jacket water system. Now the code and water system for smaller engines is optional. You will know, always see it, but our medium and large sized engines you will always have a cooler water system. This is for the same reasons as for why you have a lubrication or system on medium and larger sized engines is simply because the engine generates so much heat that you need to have a separate system in order to call down all the components. That is the sole purpose off a jacket water system. It is to call down the engine, ensure that we do know overheat the engine in this three d model. We can actually see how that occurs. So we've got a usual set up. You can see how combustion chambers there's that crankshaft on. If we go over to the side here, we can actually see a blue arrow. If you go further along, we can see a few new components that we haven't seen before. So what is happening on this really model? Well, if I can angle this correctly and if a push play, you see the blue hours here they represent. Cooling water on this one over here is actually a cooler water pump. The cooler water pump pumps cooling water around the engine. When we start the engine, the engine is cold because we haven't generated any heat due to combustion that takes a while. The engine has to be running for a little bit before we generate heat. So the cooling water that's being circulated now by the pump coming out it's coming along here and we get to something called The Thermostat is actually closed on the top. So the code award is gonna come along and flow down this point along there, and it's actually going to bypass the radiator. So if you follow my mouse for a moment, comes along here in the cooler water, goes back there and circulates back to the engine, and then the process continues. And that's essentially what the cooler water system is doing when the engine is cold. The radiator is this item here, and I'll show you what the radiators for right now because we can push play, we'll see cooler waters being circulated. The engines just sort of come online might be running a a few rpm, sort of idling, gradually heating up and as aggressively heats up, the cooling water is also going to get warmer on warmer. But we don't cool the cooling water just yet because we want the engine to be operating a certain temperature. And that is the temperature that's most efficient for combustion on. In order for the parts to operate effectively, if we call the engine at this stage, are actually just creating additional work on were more or less sucking any gel off the engine. So we don't want that. We want the engine to be hot or warm, but not too hot that it seizes. Now in a moment we should find hopefully that the color the arrows is gonna change. There we go and noticed. Now we're still circulating cooling water, but the Coonan water is going instead of down here can see it's actually blocked here so we can't bypass the radiator any longer. Back at the moment. See the blue arrows going down by passing radiator. Gradually the temperature increases the firmest that moves positions closes off the bypass and now the cooler waters so hot that the engine is saying we need to call the cooling water down because otherwise we're going over. He the thermostat expands because it's been heated up, and then the cooler water is diverted to the radiator instead of bypassing the radiator. Who's played yet? You can see he's going up here and it's going to the radiator. If we come along here, you can see the red. Our is coming down. They're passing through the radiator gonna pause it for a moment. The red arrows passing down, down, down on their passing all the way down to the bottom of the radiator, at which point the cooler water has been cooled down slightly. Then it will come along here and return to the engine. We're using air to cool down the cooling water as it passes through the radiator can see that here air is indicated by the white arrows. So it is being blown across the radiator by this fan. The family juicy, rotate Andi as it does so we're gonna call down the cooler water. So although it's not showing on this particular model, we should perhaps actually animate all of these parts to make it a little bit easier, but I think you can imagine the whole thing working. Let's imagine the Pistons going up and down. The crankshaft is rotating. This fan is rotating the cooler waters coming in. Coming down this way. The air takes away some of the heat from the cooler water. Cool awarded temperature reduces on. Then it circulates back to the engine. What we actually have is a way off maintaining the engine temperature that the desired, most efficient temperature. A Jackie order system will usually be around 80 degrees Celsius and approximately 3.5 bar off pressure. But that's essentially other cooling water system works When it's cold, we bypass the radiator on when it's hot. We call the cooling water down to a specific temperature in order that we can maintain the temperature in the engine at the optimum temperature. We actually use cooling water jackets. You can see those in this space here, including water jackets, surround the combustion space because that's where the most of the generated and they will take the heat away from the combustion space. The good and water system does not usually have any other purpose other than for removing heat from the area surrounding the combustion space. Let's load up a ceiling to sleeve, and I can actually show you that in greater detail. 12. Cylinder Sleeve: so we're actually looking at an engine ceiling to sleep now. Sitting the sleeve surrounds the combustion space. If we zoom in, you can see that we've actually got some Air Inlet ports. That's these ports here that allows the air into the combustion space. We should also have some exhaust ports. Actually, looks like the exhaust ports would be mounted on the top off the cylinder liner itself or on the top of the combustion space, so that maybe exhaust gas valves on the top here on Air Inlet ports at the bottom. Usually, this type of design is reserved for larger diesel engines, because it's more common than you have both the air and the exhaust gas valves on the top of the combustion space. Either way there comes in through these boards here. Exhaust gas looks like it's discharged out of the top. There is one other similar arrangement. Actually, we could have here where exhaust gas sports would be on the left on Air Inlet. Ports would be on the right, but anyway, let's focus on the jacket water system. The jacket water system is actually within this space. Here, conceive, we've got a gap runs all the way along the cylinder. Lina, we're going to fill that up with jacket water, and we're going to remove heat from the cylinder liner. So we're gonna take away heat from the combustion space. The jacket war itself may exit out through these holes here on it will most likely come in through the base, can actually see. There's a hole here, and it looks like that whole connects on to the jacket water. Internal passages here, maybe more than one hole could see another one here. Another one there on that ensures we get a lot of cooling water flow going into the cooler water passages within the ceiling to sleeve, and then the cooler water will flow up. Take away some of that. He flow out of the top, and we will cool down a combustion space. Normally, whenever using a liquid or a gas to take away heat, it will flow from the bottom to the top. That's because the liquid or gas heats up, and it wants to travel upwards because when you heat it up, it has a low density. So rather than trying to pump it down, imagine it's getting harder and We're trying to pump it down. We actually go the opposite direction and we say Okay, well, pumping in the bottom as it heats up, it will naturally travel up anyway. And we'll use that pump just to help it along. If we went the opposite way around, that would actually get a drop in efficiency. The same could be said when using liquid or gas that is going to be cooled down. You have a entering at the top because as it cools down, its density will increase, and it will naturally for guess downwards but use the pump just to help it along. So there's no point fighting the natural laws off conviction because they're always going to be present. So if it's a liquid or a gas, that he's going to become hotter as it takes away he and pump it in at the bottom and allow it out of the top. If it's a liquid or a gas, that is going to become colder and pump it into the top and take it out off the bottom on that logic is true for many heat exchangers and industrial machines. So now we know a little bit about the Cuban water sister on what it's used for. What are some of the important design considerations associating with a cooling water system? Well, the 1st 1 and perhaps most important, is that water can freeze if water freezes in, your engine is going to expand on if that occurs, the parts within the engine and not gonna be able to contain the water anymore, and you're going to crack some of the components in the engine. So let's imagine for a moment that we had cooling water in these passages. It freezes, the water expands, and we're gonna have lows of cracks that appear on a cylinder Lina. Now, cylinder liners are not necessarily cheap. You may crack the entire cylinder block off the engine itself, and that will render the engine almost totally inoperable and you won't be able to repair. So in order to get around this problem, we dose cooling water with antifreeze. That means that the cooler water could be exposed to sub zero temperatures on it will not freeze, so antifreeze is very important. Usually it's mixed in with the cooling water itself. The other thing that's mixed in with cooling water quite often is a corrosion inhibitor. The corrosion inhibitor essentially just stops all of these internal passages. So will the area inside here from rusting. So hopefully that clarifies in your own mind what cooler water is on its function within the engine. Let's move on to our final system now, which is the electrical system also referred to as the electronic system. 13. Electrical System Part 1: now, I had a look earlier to see if I can find a suitable Freedy model so I could show you the electrical system. But unfortunately, we don't actually have one at the moment, so I do apologize for that. However, I can talk you through the entire process and hopefully that will help you understand why we have electrical circuit for an engine on why engines are becoming more and more reliance on electron ICS. The main reason that we require a battery for an engine is to start the engine. The battery does other functions in a car, for example, such as supplying power to the headlights on may be few your electronic dashboard etcetera , but in terms off combustion engines, it is there to start the engine that is its primary purpose. So how do we start the engine? Well, we start the engine using a starter motor. Now this is a starter motor. What actually happens is starter Motor has a gear wheel, and we push it in to the flywheel on the gear, will engages with the flywheel and causes it to rotate. That all happens in this section here. Spin around may be able to see the gears. But if not, I'll load up a model and show you in a moment. Okay, so it's happening in this section here. I'll load up a separate model so I can show you that in greater detail. Okay, so here we are. We're looking at the inside off a internal combustion engine is the four strike engine. Conceal the components. The starter motor engages with the gear teeth on the flywheel. See, from this angle, we've got some gear teeth on a little starter motor. Imagine that it faces this direction. It has its own set off Gerety, and they will slot into these points here. And as the starter motor of rotates, for example, clockwise. It's going to cause the flywheel to rotate as well, and that's going to rotate the crankshaft, and that's going to force the Pistons up and down. We can actually see that occurring here, and the Pistons will be forced up and down, and at that point you can inject fuel. Andi, after a few revolutions, the Angel star and it will be able to maintain its own momentum. Let's just start the animation again. I can see all the Pistons are operating, the valves are operating. Actually, like camshaft running through the middle. The flywheel is rotating, but we have to imagine is starter motor. It actually engages with the flywheel and gives it that initial push in order that the Pistons could move up and down. And then we can inject fuel and get combustion. A Sooners. The engine is operating underneath the time power. We removed the starter motor on. We'll take it away from the gear teeth on the flywheel, and that stops the starter motor burning out sometimes, and I've actually had this happen to me. The starter motor stays engaged with the gear teeth on. What will actually happen is the starter. Motor burns out. You'll have a copper burning smell, and that's because the starter motors being dragged along by the engine flywheel. That shouldn't occur because the starter motor should disengage with the flywheel. It's just sometimes gets very dirty and intends to stick. Not only that, but use a valve. It's called a solid valve to push starter motor into the flywheel, and you use a spring to retract it again. If the spring gets tired, then all of a sudden your starter Motor will not disengage with the flywheel. He's actually quite a common fairly mode for Starter Motors, but anyway, we start the engine using the starter motor on. We operate the starter motor using the electrical power from the battery. Usually the voltage we use is going to be 12 volts or 24 volts. Direct current, that is to say, a 12 4 DC battery or a 24 volt DC battery. So that is the primary function off a battery when used with an internal combustion engine . You may notice that with smaller engines, you don't have a battery. This is because where there is no battery, you'll often have a poor record. For example, with the leaf bow, your sometimes grabbed the ball called and your pull it as hard as you can. And that gives the engine the initial push, the initial momentum it needs in order to inject fuel, and then it will continue to operate under its own momentum. Without this initial push, you cannot start the engine. Let's imagine for a moment we were injecting fuel into the combustion space can actually see our injectors here will inject the fuel and what will happen while the engine is sitting as it is right now, it's just sitting completely still. If we spray fuel into the space, nothing's going to happen. You may have heard the phrase flooding the engine. If that actually occurs, you'll get a lot of black smoke coming out of the exhausts. That indicates to anyone looking at the engine that you have used too much fuel and not enough oxygen. That's when you get black smoke coming out of the exhaust. If you get white smoke coming out of exhaust, you've used too much oxygen, too much air and not enough fuel. And if you get blue smoke coming out of the exhaust, your burning lubrication oil so black, white, blue, too much fuel, too much air on burning lubrication oil. So those are handy tips if you ever looking at the exhaust gas off an internal combustion engine. But let's not digress too much. Let's have a think about some of the other systems where we could use electrical current in order to make the engine more efficient 14. Electrical System (Part 2): Now, we've already discussed the starter motor. See the electrical connections on the side here. But in order that we don't have a flat battery, sometimes called a dead battery, we're going to need an alternator. I'm not sure if you've got one in the same gym, but I have a look around. The other side could see that there are some devices that run directly off the engine Crankshaft. We're using a belt on this arrangement. Maybe a belt, maybe gears, maybe a chain. So let's have a look at some of the things that are running off the engine. Got this round Circular one here. This maybe, perhaps a jacket. Water pump. We've got attention in device that keeps the belt tight. We've got another device here. I believe that's for the lubrication. All system on again. We've got attention, er, to keep the tension on the belt. Always the same. We don't want to. Slack built. We always wanted to be quite tight. Now I can actually see the alternator on this particular engine, which is quite interesting because it should definitely be there. But irrespective normally you have an alternator that is driven off the engine itself. And this is what we call a parasitic load. In fact, all of these loads here, you can see one load here, another load up here. Those are parasitic lows there drawing energy away from the crankshaft. So we're not using that energy to make the car move or anything like that. We're just using that energy to supply our life support systems such as the jacket, water pump, lubrication or pump. Maybe the alternator, etcetera. The alternator charges the battery. So we use a lot of current to get the engine started, and then we're going to replace the current by using an alternator which is gonna feed electrons to the battery, which is going to restore the battery back to its normal working condition. Think of a battery a little bit like tank for electrons. If you think the electrons out of the tank were out of the battery, you need to replace them again. There's not an infinite amount of electrons in a battery, So if we draw 50% of the electrons out of the battery just to get the engine rotating, then we need the alternator to feed electrons back into the battery. So that the battery is full of electrons again. If you have a flat battery, it means all of the electrons have left the battery. They've flowed to a different area, so we've got the alternator, which is filling a battery up with electrons. And then we've got the starter motor, which is using a lot of those electrons to start the engine. But there are other things that are going to draw electrons out of the battery or directly from the alternator itself. If you've got loads off flashing blinking lights when you drive your car, such as when you light up the interior of your car, even switching on the small lights on the front, the back or when you turn your headlights on, or even when you have those red hazard lights on there all drawing electrons from the battery or if the engines in service. Sometimes there's really electrons directly from the alternator, so the electrical system not only consists of the battery in the alternator, which are essential in order to start most engines. But the electrical system may also be used for many over auxiliaries, such as for headlights for hazard lights for electronic displays etcetera. Another area, though, where you're likely to see a lot of electron ICS is the electronic control system associated with the timing of the engine. You may use a complete electronic system for the fuel injectors by zoom in. We may see that these fuel injectors are electronic. It may not be. See the fuel connection coming down here. See the fuel injectors. But these fuel injectors do not appear to be Elektronik. Some fuel injectors are having electronic fuel injectors just increases the engines overall efficiency because we can mawr specifically time when the injector opens and closes a lot off modern medium and large size engines. Fact, even quite small sized engines used in cars are going to be completely controlled electronically. All of the temperature alarms, pressure alarms, temperature sensors, pressure sensors, level sensors. All of that information is going to feed into a central computer. We call this an engine control unit sometimes engine control module or sometimes even made Elektronik. Governor. The point is, all that information floods into this computer, and we're gonna use that computer to control the engine. You can think of it as being the brain off the engine because It's the brain of the engine . It is very, very important. It might be a relatively small component on the engine, but if you have any problem with this engine control module, the whole engine will no longer function. Now, I have personally experienced this. When I was on a ship floating around just off the coast of France on both of our engines died at the same time and we couldn't get the engines restarted and we were drifting closer and closer to the coast. But a song we actually got the engine started again. We're about 200 meters away from land, which is where you don't really want to be when you're on a ship. The problem we had was that somebody had taken the engine control my jaw on, mounted it onto the side of the engine. When the engine became hot, was actually mounted round about here. The engine control module overheated on it became very erratic. The injectors were injected at the wrong time. The engine was accelerating and decelerating very erratically, and eventually the engine just shut down. Now it took us quite a long time to find the cause off this issue and it was actually by taken engine control module off the engine that allowed it's cool down. And then we discovered this was actually the problem. Now I'm a big fan of increasing engine efficiency, and I definitely believe it's a really good thing if you can get more power out compared to what you put in. But the reliance upon electrical systems nowadays, especially electronic control systems, has got to such a point that if you do have any problem with a Elektronik governor, the engine one no longer operate. So keep a look out for that. If you have a modern engine, your experience in slightly erratic problems that perhaps you can explain very easily. 15. Final Thoughts: welcome to the final lesson off this course. Now, at the start, of course, I said you were going never look at the exterior of an engine and go through and start dissecting it and trying to figure out what each of the parts are. I want to give you an example. We know that air has to be drawn into the engine for combustion. And if we look around here, do you recognize this item? Besides him, here is a turbocharger that we saw a little bit earlier on in the course. So what I'm wondering now is which side is for air on which side is for exhaust gas. Now we know it gets sucked into the middle. So I go through this hole here or on the opposite side. We can't see the turbine and compressor wheel because this is a simplified model. But let's have a look. If we stopped there in here, then it would go out and it would be discharged through this point and it would go into the engine on the other side. Which suck. Arian comes out, comes along here long here, and then it goes into the engine again. This is the combustion space because the rocker arms are housed inside here. So I try to visualize that in your mind the rocker arms and the tops of the valves are inside each of these black boxes, which means the combustion spaces just below. Which means the Pistone top that center is probably gonna be around here on bottom, dead center, maybe here, moving up, Down, up, down. But is this for exhaust? Or is it for air? Well, it's most likely not for air. Why do I say that? Because we're not cooling the air down After it left, the turbocharger could see comes out here along their straight to the combustion space. So I would argue this is an exhaust gas manifold. We go along over here. Crk let's imagine we're sucking air in for this side has more of a snail like shape. Snail shape here on that indicates to me that this is probably a veloute casing on with discharge here here, and it's going into the engine and it looks like it's going into this black box on the top . If I spin around, we can actually see that there is a big manifold coming out of the box here that season. Tyre section Andi on the opposite side. This manifold is slightly bigger than the one over here. So imagine for a moment the star exhaust gas manifold, he looks slightly smaller than this one. We know that we need Mawr Air to go into the combustion space to flush out some of the exhaust gas and also to ensure we have enough air within the cylinder Lina in order to get a fishing combustion. So I would say this item on the top here has something to do with their cooling. So we compress the air, comes out the areas and called, comes out again into the air manifold into the combustion space conceal where it connects onto the combustion space here. So we just used our knowledge to find the air system on the exhaust gas system, and we can do the same thing to find the lubrication or system on the jacket water system. It's been the engine around for a moment. We know that the jacket water pump is going to be driven off the crankshaft. We know the lubrication or pump is going to be driven off the crankshaft So it's most likely going to be one of these. This one here. Well, this one here, it's gonna be driven by belts. May be a chain or maybe gears, and so we can focus in on these two items that would be one here on one over here and try and discover what those two items are. Now, if I go down here, you can see the belt is attached onto a pulley and there's a shaft which probably runs through the middle. Here, let's have a look what's connecting onto this particular component? There was some pipes coming off it here. One of the pipes goes into the engine. Another one comes down. Down. What is that one going? It's going into the bottom of the engine. I remember before we had an oil sump. There is a place where we store our oil. That's gonna be around this whole section here. If you have a look in the bottom, we can see where we drain the oil. That would be through this hole here. So if you're doing an oil change, that's where you would drain the oil. So I'd say Okay if we've got a pipe that connects onto your reservoir, perhaps will be another pipe connecting onto the old reservoir as well is one here? We follow that. Where's it going? Coming up here. Coming up here again. Not one guy. She goes off and out of the engine. So I would argue that based upon this pipe here on also the fact that is another point connecting onto side the engine. This is most likely for the lubrication oil system. Now, I always say most likely because I never like to work with. This is definitely this or I'm certain it's this because as soon as you take this mentality , you are highly likely to take yourself down the wrong path. Always leave your options open. We're gonna shoot that. This part here relates to lubrication oil system because we have this connection here. Now is to the or some on, because there's another royal connection that comes across here. If you wanted to go a bit further, then we could look for the oil filter and see what attach is to that. Or look for the fuel filter and see what it's actually Stowe, that, But because you know all of the systems Now you can break this engine down into its parts and start to analyze what you think each component is on what its purposes. Now. I'm not going to go through every single component because I think that's a really good challenge for you to do. At the end of this course, there are links in the resources section off this course to all of freely models that you have seen throughout the course. So click on those links, load up the freely models, learn the names off the engine components, learned the terminology, look at all of the systems and memorize each system and then come here, pushed the annotations icon on. If you go around the engine, you can click on the various parts, and it will explain to you exactly what each of the parts are, and you can confirm your own suspicions. Once you're happy with that, you can take the quiz click on the crankcase breather filter, actually know it's there, and you will see your score on the right. The quiz feature is present on a lot of three D models, so there is a lot of opportunity to consolidate what you have learned throughout this entire course, and I really do encourage you to do that. I hope you enjoy this course. I hope you learned a lot. I hope it was fun on not too overwhelming. Savary courses are designed to be very visual. I try to present them in such a way as to allow you to learn not just from the freely models but also from my own experience. I hope that came across quite well. If you've got questions or comments, then please do get in touch. We are always looking for new ideas for courses on. We are constantly improving these courses on. We can only do that if we have feedback from the students and they tell us things that worked well on things that didn't work so well once again. I hope you enjoy the course. This is the most important thing to me. Learning should always be fun on. I hope to see you another course soon. Thanks very much for your time.