What is an engine?

Most modern cars use an internal combustion engine (ICE). Internal combustion engines convert fuel into motion via explosions inside themselves.  The motion generated by the engine is then used to perform some sort of task, such as turning the wheels of your car, the blade of your chainsaw, or to generate electricity for your house when the power goes out.

How does an internal combustion engine work?

Modern internal combustion engines work via the four-stroke cycle. This means that there are four “strokes” that a piston moves through inside the engine to get its job done. The four strokes are intake, compression, combustion, and exhaust. Let’s dig into those a bit deeper.

Intake

The intake stroke begins with the piston at a position very near the valves called top dead center (TDC). During the intake stroke, the intake valve opens, the exhaust valve closes, and the piston is pulled by the crankshaft away from the intake valve. This creates a vacuum inside the cylinder which causes air to enter the cylinder. In some vehicles, gasoline has already been injected into this air; in others, the gasoline is directly injected into the cylinder. This works just the same as how we breathe; our diaphragm moves down creating a vacuum in our lungs which draws air in.