How Do Car Engines Work? (Simplified)

Car engines are complex machines, but they can be simplified into four main components: the engine block, the cylinder head, the pistons, and the crankshaft. The engine block is the main housing of the engine, and it contains the cylinders. The cylinder head sits on top of the engine block and contains the valves that control the flow of air and fuel into and out of the cylinders. The pistons move up and down inside the cylinders, and they are connected to the crankshaft by connecting rods. The crankshaft converts the up-and-down motion of the pistons into rotary motion, which is then used to drive the wheels of the car.

The Engine Block

The engine block is a casting that forms the main structure of the engine. It contains the cylinders, which are bored into the block. The cylinders are where the pistons move up and down. The engine block also contains the oil passages that lubricate the moving parts of the engine. The cylinder head sits on top of the engine block, and it contains the valves that control the flow of air and fuel into and out of the cylinders.

The Cylinder Head

The cylinder head is a casting that sits on top of the engine block. It contains the valves that control the flow of air and fuel into and out of the cylinders. The valves are opened and closed by the camshaft, which is driven by the crankshaft. The cylinder head also contains the spark plugs, which ignite the air-fuel mixture in the cylinders.

The Pistons

The pistons are cylindrical castings that move up and down inside the cylinders. They are connected to the crankshaft by connecting rods. The pistons compress the air-fuel mixture in the cylinders, and they also transfer the force of the expanding gases to the crankshaft.

The Crankshaft

The crankshaft is a forged steel shaft that converts the up-and-down motion of the pistons into rotary motion. It is supported by bearings in the engine block. The crankshaft is connected to the transmission, which drives the wheels of the car.

The Four-Stroke Cycle

The four-stroke cycle is the sequence of events that occur in each cylinder during the operation of a car engine. The four strokes are:

1. Intake stroke
2. Compression stroke
3. Power stroke
4. Exhaust stroke

The intake stroke begins when the intake valve opens and the piston moves down the cylinder. This creates a vacuum in the cylinder, which draws air and fuel into the cylinder from the carburetor or fuel injector. The intake valve closes at the end of the intake stroke.

The compression stroke begins when the piston starts to move up the cylinder. This compresses the air-fuel mixture in the cylinder. The compression stroke ends when the piston reaches the top of the cylinder.

The power stroke begins when the spark plug ignites the air-fuel mixture in the cylinder. This causes the air-fuel mixture to burn and expand rapidly. The expanding gases push the piston down the cylinder. The power stroke ends when the piston reaches the bottom of the cylinder.

The exhaust stroke begins when the exhaust valve opens and the piston starts to move up the cylinder. This pushes the exhaust gases out of the cylinder and into the exhaust manifold. The exhaust valve closes at the end of the exhaust stroke.

The four-stroke cycle then repeats itself.

Conclusion

Car engines are complex machines, but they can be simplified into four main components: the engine block, the cylinder head, the pistons, and the crankshaft. The four-stroke cycle is the sequence of events that occur in each cylinder during the operation of a car engine.