Engine For the record company, see Motor Music. Jet engine 1915, with provision and water-cooled radial. V12 engine car, used in a Lamborghini Murcielago. An engine is a portion of a machine capable of transforming any type of energy (electricity, fossil fuels …), into mechanical energy capable of performing work. On cars this effect is a force that produces motion. There are several types, the most common: heat engines, where work is derived from thermal energy. Internal combustion engines are heat engines in which combustion occurs in the working fluid, changing its chemical energy to thermal energy, from which mechanical energy is obtained. The fluid before starting the engine combustion is a mixture of an oxidizer (such as air) and a fuel, such as those derived from petroleum, natural gas and biofuels.External combustion engines are heat engines in which combustion occurs in a fluid other than the working fluid. The working fluid temperature reaches a higher energy state by transferring energy through a wall. Electric motors, when work is obtained from an electrical current. In wind turbines, hydroelectric or nuclear reactors also becomes a kind of energy into another. However, the word engine is reserved for cases in which the immediate result is mechanical energy.