A big technical encyclopedia "Internal combustion engine": gasoline engine, diesel engine, cylinder head, combustion chamber, dohc, spark plug, fuel pump, injection system, exhaust system. An internal combustion engine is a type of heat engine in which the fuel mixture is burned inside the engine in a combustion chamber. Such an engine converts the energy of fuel combustion into mechanical work. In spark ignition engines, such as petrol (gasoline) engines, the combustion chamber is usually loc