petrol engines

Synonyms

gasoline engines

Definition

A petrol engine (known as a gasoline engine in North America) is an internal combustion engine with spark-ignition, designed to run on petrol and similar volatile fuels. It differs from a diesel engine in the method of mixing the fuel and air, and in the fact that it uses 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 now 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, conrods & crankshaft (as a result of lower compression ratios) & due to petrol burning faster than diesel. However the lower compression ratios of a petrol engine gives a lower efficiency than a diesel engine.

Wikipedia definition:

A petrol engine (known as a gasoline engine in American English) is an internal combustion engine with spark-ignition, designed to run on petrol (gasoline) and similar volatile fuels. The first practical petrol engine was built in 1876 in Germany by Nikolaus August Otto, although there had been earlier attempts by Étienne Lenoir, Siegfried Marcus, Julius Hock and George Brayton. The first petrol combustion engine (one cylinder, 121.6 cm3 displacement) was prototyped in 1882 in Italy by Enrico Bernardi. In most petrol engines, 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 it is done by electronically controlled fuel injection, except in small engines where the cost/complication of electronics does not justify the added engine efficiency. The process 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 very hot air at the end of the compression stroke, and self-ignites.

Source: Wikipedia - Petrol engine