The battery supplies the power necessary to start the engine when the ignition switch is is turned on.

Normal combustion in an engine is initiated by a spark plug and results in the complete burning of the air-fuel mixture. If combustion is initiated by a source other than the spark plug, by a hot spot in the cylinder or combustion chamber for example, pre-ignition results. Detonation results if the air-fuel mixture explodes instead of burning. Detonation can cause extremes in pressure in the combustion chamber leading to engine damage.

The crankshaft converts the reciprocating motion of the piston into the rotational motion that's used to power the vehicle and its components.

The fuel injector sprays fuel into the air stream that's being fed into the cylinder head via the intake valve. The timing and amount of fuel are regulated by the powertrain control module (PCM) which is the main computer that controls engine and transmission functions.

The water pump is driven by a belt connected to the crankshaft and ensures that coolant moves through the engine and radiator.