internal combustion engine

internal combustion engine

An internal combustion engine is a type of engine, widely used in cars and motorbikes, in which fuel is burned inside, so that the gases formed can produce motion. An internal combustion engine may be a two-stroke engine or a four-stroke engine. In the most common type of engine, a mixture of gasoline vapor and is ignited by a spark plug. The gases produced in the resulting explosion drive a piston down along a cylinder. A crankshaft changes the reciprocating (to-and-fro) movement of the pistons into rotary motion. In the Wankel rotary engine, the gases produced in the explosions drive a triangular rotor. The diesel engine in another form of internal combustion engine.


Key to diagram

An in-line, four cylinder gasoline engine is the most common internal combustion engine used in cars. Air is sucked through a filter (1) into the carburetor (2), where it mixes with the gasoline. This mixture then enters the cylinders through the dual inlet valves (3) on each cylinder (4). The spark plug (5) then ignites the mixture forcing the piston rapidly down. The burnt gases are expelled through the outlet valves (6). The reciprocating motion of the pistons is converted into rotation by the crankshaft (7). The crankshaft also turns the timing belt (8) that controls the opening of the valves, through the cams (9) located on the camshaft (10), and also the firing of the spark plugs.