Fuel injection has replaced the carburetor as the primary automobile fuel delivery system. The main difference between the fuel injector and the carburetor is that fuel injection atomizes the fuel by forcibly pumping it through a small nozzle under high pressure while a carburetor relies on suction to draw fuel into an accelerated intake air stream.

Both drum brake and disc brake assemblies use friction to stop a car's wheels from turning but each do it in a slightly different way. A drum brake assembly uses a large iron drum attached to the wheel and brake shoes that press against the drum to slow the rotation of the drum and, consequently, the wheel. A disc brake assembly employs friction in the same way as a drum brake but instead uses a rotor, also attached to the wheel, and two brake pads that squeeze against the surface of the rotor.

The camshaft is linked to the crankshaft through a timing belt and regulates the opening and closing of the intake and exhaust valves in each cylinder in time with the motion of the piston. An engine designated OverHead Camshaft (OHC) locates the camshaft in the cylinder head. An engine with Double OverHead Camshaft (DOHC) has two camshafts, one to regulate the intake valves and one to regulate the exhaust valves.

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 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.