The purpose of an automobile engine's cooling system is to circulate coolant around the engine so it can absorb and dissipate heat. The water pump pumps coolant through the various components in the system and the radiator cools down coolant after it has heated up after passing through the engine. The thermostat controls the flow of coolant based on engine temperature while the cooling fan draws air through the radiator when the car isn't moving fast enough for unforced air to cool things down on its own.

Ignition timing defines the point in time at the end of the compression stroke that the spark plug fires. Measured in number of degrees before top dead center (BTDC), the exact point that the spark plugs initiate combustion varies depending on the speed of the engine. The timing is advanced (the spark plugs fire a few more degrees BTDC) when the engine is running faster and retarded when it's running slower.

The catalytic converter converts pollutants in exhaust gas into less pollutant substances like carbon dioxide and water.

Spark plugs receive current from the distributor and use it to spark combustion in the combustion chamber of a cylinder.

In a four-stroke cycle engine there is always one piston delivering power, one exhausting gases, one drawing in the air-fuel mixture, and one compressing that mixture.