During the power stroke, just before the piston reaches top dead center, the spark plug fires and ignites the compressed air-fuel mixture. The resulting expansion due to combustion pushes the piston back down the cylinder toward bottom dead center.

Actuators receive signals from the PCM and carry out adjustments needed based on the data the PCM received from the sensors.

The engine (or cylinder) block is the large casing that contains the cylinders and many of the internal components of the engine.

The lubrication system lubricates engine components by putting an oil film between them to reduce friction and smooth engine operation, cools by absorbing heat from engine parts, seals the pistons and cylinders to contain combustion, cleans contaminants, and quiets engine noise.

The fluid reservoir stores the brake fluid that the master cylinder uses to maintain hydraulic pressure.