Speaker A
Hey everyone. Now, in this video, I'll be explaining car engines. Now, I know that for a lot of my subscribers, this will probably be just mostly review, but I want to have a starting point where if someone
A clear explanation of how four-stroke gasoline car engines work, covering components, operation cycles, and torque transmission.
Key Takeaways
- A four-stroke gasoline engine operates through intake, compression, power, and exhaust strokes.
- The camshaft controls valve timing to regulate air and exhaust flow in the cylinders.
- Pistons convert combustion energy into rotational torque via the crankshaft.
- Torque is transmitted through the drivetrain to the wheels, enabling vehicle movement.
- Understanding basic engine operation is foundational before exploring more complex automotive systems.
What the video covers
- Introduction to car engine components including fuel injectors, camshaft, valves, pistons, connecting rods, crankshaft, and spark plugs.
- Explanation of the four-stroke gasoline engine cycle: intake, compression, power, and exhaust strokes.
- Details on how air-fuel mixture is drawn in, compressed, ignited, and expelled during engine operation.
- Description of how pistons convert vertical motion into rotational torque via the crankshaft.
- Overview of how torque is transferred from the crankshaft to the flywheel, clutch or torque converter, transmission, driveshaft, differential, and finally to the wheels.
- Clarification of engine configurations such as V6 and V8 based on cylinder count.
- Explanation of camshaft function in opening and closing valves during different strokes.
- Mention of the flywheel’s role in maintaining engine momentum and smooth operation.
- Encouragement to explore more detailed topics like clutches, transmissions, and different engine types.
- Recommendation to watch a follow-up video comparing diesel and gasoline engines.
Chapters
- 00:00Introduction to Car Engines
- 00:23Engine Components Overview
- 00:44Cylinder and Piston Explanation
- 01:33Four-Stroke Engine Cycle Introduction
- 01:38Intake Stroke Explained
- 02:18Compression Stroke Explained
- 03:05Power Stroke Explained
- 03:30Exhaust Stroke Explained
- 04:24Torque Transmission and Drivetrain
- 05:12Summary and Further Learning Recommendations
Full Transcript — Download SRT & Markdown
Speaker A
comes in new, they can have a good way of getting to see how cars work.
Speaker A
So this is that way. And so we are going to talk about engines and how they work.
Speaker A
So first, I'm just going to go through pretty much all the components within the engine, and then I'll talk about how they work together.
Speaker A
So just starting at the top, we've got fuel injectors which spray fuel into your intake manifold. Here, we got a camshaft that's responsible for opening valves that allow air to go in or out of the cylinder.
Speaker A
We've got rocker arms which connect the camshaft to the valves. We've got these valves here which open and close, allowing air to come in or go out depending on which side.
Speaker A
We've got the cylinder here, so depending on what kind of engine you have, the V8, V6, that's how many cylinders you have: six cylinders for V6 and 8 for a V8. So we got a piston here. This is what
Speaker A
moves up and down, and when you turn this vertical motion into rotational motion in order to move your car. We've got a connecting rod which connects the piston to the crankshaft. We've got the crankshaft which is connected to all the different pistons within the engine
Speaker A
and so they all supply the torque to this rod. And then we've got a spark plug which ignites the air/fuel mixture which you put in. So this video we're going to be looking at a four-stroke gasoline engine, pretty much most common
Speaker A
here in America, so that's why I chose it. So how does all this work? Well, you've got four strokes, so I got to go through each of these so I can explain what's happening here.
Speaker A
So your first stroke is intake. So when you have your intake stroke, this valve here, your exhaust, is going to be closed.
Speaker A
This camshaft here is going to be rotated enough so that this valve is pushed open. There is a little spring here that compresses and opens this valve.
Speaker A
When it is compressed, when that's pressed down, this piston is going to be at the top and it is going to be moving down. So that piston moves down, it's going to pull an air-fuel mixture into this cylinder, so that the air-fuel mixture comes in from the fuel injector and the air
Speaker A
coming in from your intake. So that's going to be the first step: pulling in the air-fuel mixture into this cylinder chamber.
Speaker A
So that this piston will be all the way down here, at the bottom. Now your next step is compression.
Speaker A
So for compression, both of these valves will be closed. This camshaft will be rotated in a manner that neither of these are open. So you can see there is a little lobe here, and it rotates about this center duct, so it only opens when the camshaft is pointed toward those,
Speaker A
otherwise they're going to remain closed. So both of these valves are closed, and our piston is down here at the bottom.
Speaker A
Now the next step is compression. That piston is going to move back up, and as it moves back up, it's going to compress the air and the fuel that are then put inside of the cylinder. Now finally the power stroke, once that piston gets all the way to the top, a spark ignites
Speaker A
and you have a little explosion that occurs, and here's that fire spread, and it forces that piston back down into the bottom.
Speaker A
Now you've got just exhaust gases in here. You've burnt up the oxygen; there is no oxygen remaining, but if you've burnt it perfectly, and so you want to get rid of that air. So this camshaft here will rotate and push this rocker arm, so this will open up this
Speaker A
valve, and as the cylinder, as the piston comes back up, it pushes out the exhaust gas out of this exhaust, the headers here. So that's the final step.
Speaker A
So let's once again go through those real quickly: intake, you're pulling in the air and the fuel, that cylinder, that piston moves down; compression, you're just squeezing all that air and fuel mixture into a very small space.
Speaker A
Power stroke, you ignite that air-fuel mixture that pushes the piston down providing a torque on that crankshaft; and then exhaust, you want to get that air squeezed back out, so the piston comes back up and pushes out the remaining exhaust, and then the cycle just repeats itself
Speaker A
and goes on and on and on. So let's look at the big picture. So here, we've got a basic two-cylinder engine connected to the crankshaft. So what happens after you've supplied that torque to the crankshaft?
Speaker A
Well, that torque helps rotate the flywheel which is connected to the crankshaft, and that flywheel maintains a momentum that keeps the engine running smooth, and it is attached to a clutch.
Speaker A
If you buy a brand new car or a torque converter if you buy an automatic car. Now that then passes to a transmission depending on automatic or manual transmission, and then so you have gears in there, to change up the speeds, and the torque passing through, and then ultimately
Speaker A
you pass that torque to the drive shaft. Now the drive shaft sends the torque to a differential which puts the torque between the left and the right tires. Now this can go either in the front or the back.
Speaker A
In this drawing here, I've got it going to the rear wheels, so these rear wheels are driving, and so that ultimately that torque passes to these two wheels, they rotate, and the car moves forward. So that's the general idea of a car engine and how it moves you.
Speaker A
Now I've got topics on all of these in much bigger details and different types, so you can go in and look at those and understand all these much better. So this is a great starting point to see the general picture of how it all works, and then from there you can
Speaker A
get into more detail of, say, a clutch or torque converter, different transmissions, and you know, flywheel, the engine, different types of engines, suspension setups, everything. So it is a great starting point if you understand all this.
Speaker A
And probably the next video that you should watch after this would be diesel versus gasoline, and that would explain in detail how a diesel engine differs from a gasoline engine.
Topics:car enginefour-stroke enginegasoline engineengine componentspistoncrankshaftcamshaftvalvestorque transmissionautomotive basics
