During the compression stroke, both intake and exhaust valves are closed as the piston begins moving back up from the bottom of the cylinder (bottom dead center or BDC). This compresses the air-fuel mixture in the combustion chamber which also makes it hotter.

The ignition coil is a high-voltage transformer made up of two coils of wire. The primary coil winding is the low-voltage winding and has relatively few turns of heavy wire. The secondary coil winding is the high-voltage winding that surrounds the primary and is made up of thousands of turns of fine wire. Current flows from the battery through the primary coil winding which creates a changing magnetic field inside the secondary coil. This induces a very high-voltage current in the secondary coil which it feeds to the distributor.

Sensors provide the data necessary for the vehicle's computer to make decisions and monitor everything from simple vehicle information like tire pressure to complexities like the chemical content of an engine's exhaust.

A water jacket is a coolant-filled casing that allows heat transfer from the engine block and cylinder heads to the liquid coolant.

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