The battery supplies the power necessary to start the engine when the ignition switch is is turned on.

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.

Because a compressed spring will ex­tend violently, shock absorbers must be used to dampen the spring’s compression and extension cycles. Struts combine the spring and shock into one unit

The cylindrical solenoid is a relay that safely connects the high amperage battery to the starter motor when the ignition key is turned. This current then allows the engine to turn at a high enough speed to start.

The transfer case splits engine power between the front and rear axles of four-wheel drive vehicles.