Cylinders act as a guide for the pistons that translate the heat energy of combustion into the mechanical energy necessary to move a vehicle. Piston rings seal the piston to the cylinder to contain combustion gases and also regulate the oil distribution between the piston and cylinder wall. A cylinder head closes in the top of the cylinder forming the combustion chamber which is sealed by a head gasket (head). The head provides space for air and fuel intake valves, exhaust valves, and mounts for spark plugs and fuel injectors.

Inline cylinder arrangements number cylinders sequentially (1, 2, 3, ...) front to rear.

The transmission provides the appropriate power to vehicle wheels to maintain a given speed. The engine and the transmission have to be disconnected to shift gears and a manual transmission requires the driver to manually manage this disconnection (using a clutch) and to manually shift gears. An automatic transmission is essentially an automatic gear shifter and handles this process without driver input.

The muffler follows the catalytic converter and absorbs sound to help quiet load exhaust. It is followed by the exhaust pipe which is the final exit point for exhaust gas from the vehicle.

A head gasket is a gasket that sits between the engine block and cylinder heads to seal the cylinders to ensure maximum compression and avoid leakage of coolant or engine oil into the cylinders.