June 09, 2025

Basic engine function

The fresh air and fuel drawn in through the air cleaner is combusted inside the engine, producing an explosion. This explosion provides a large amount of power.
This large amount of power pushes the piston down to turn the crankshaft, producing rotational power and turning the tires through the drivetrain.

4 cycle gasoline engine operation
Engine types include gasoline engines, diesel engines, and more. Now let's learn how the 4 cycle gasoline engine works, the most commonly used engine.
In the 4 stroke gasoline engine there are four cycle, from when the engine takes in the air-fuel mixture (the mixture of air and gasoline) until it discharges the exhaust gas.
Let's view the animation and see how each stroke works.

Intake stroke
The exhaust valve closes and the intake valve opens. As the piston drops the air-fuel mixture is sucked into the cylinder from the open intake valve.

Compression stroke
As the piston goes down BTDC, the intake valve closes. The air-fuel mixture drawn into the cylinder is compressed as the piston rises.

Combustion stroke
At the end of the piston's ascent, electricity flows to the spark plug, creating a spark which causes the compressed air-fuel mixture to combust and explode.
This explosive force pushes the piston down, rotating the crankshaft. It is power that drives the vehicle.

Exhaust stroke
As the piston finishes descending, the exhaust valve is opened, and as the piston rises it pushes the post-combustion exhaust gas out of the cylinder.