Petrol Fuel Engine

Fuel may be metered, or sent, to the cylinders by either a carburettor or an injection system. Therefore, reciprocating engines are also classified as carburetted or as fuel-injected engines. Because combustion depends upon both air and fuel, the power of an engine is limited by the amount of air reaching the cylinders. To increase power, an engine may be supercharged or turbocharged. A supercharger is an engine-driven pump, and a turbocharger is an exhaust-driven pump. Both pumps force extra air into the cylinders, increasing the engine power. The air needed to burn 1 unit of petrol weighs about 15 times as much as the petrol.