Petrol Engine

A petrol engine (known as a gasoline engine) is an internal combustion engine with spark-ignition, designed to run on petrol (gasoline) and similar volatile fuels.

It differs from a diesel engine in the method of mixing the fuel and air, and in using spark plugs to initiate the combustion process. In a diesel engine, only air is compressed (and therefore heated), and the fuel is injected into the then very hot air at the end of the compression stroke, and self-ignites. In a petrol engine, the fuel and air are usually pre-mixed before compression (although some modern petrol engines now use cylinder-direct petrol injection).

The pre-mixing was formerly done in a carburetor, but now (except in the smallest engines) it is done by electronically controlled fuel injection. Petrol engines run at higher speeds than diesels, partially due to their lighter pistons, con rods and crankshaft (as a result of lower compression ratios) and due to petrol burning faster than diesel. However the lower compression ratios of a petrol engine give a lower efficiency than a diesel engine.


Uses of Petrol Engine

Motor cars
Motorcycles
Aircraft
Motorboats
Small machines, such as lawn mowers, chainsaws and portable engine-generators


Petrol engines may run on the four-stroke cycle or the two-stroke cycle.

Posted in: Engine,Machine,Petrol