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 firing order of the cylinders in an engine is different than the cynlinder numbers and can be found by observing the order in which the intake valves open.

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

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.

An automotive battery produces direct current for use by automotive systems.