1. Injection systems

1.1 Mixture formation in reciprocating engines

In order to perform its functions, the injection system is schematically made up of a fuel reservoir, a filter element, a pump for delivering a certain flow of fuel at a sufficient pressure, a metering element and an injection orifice for atomizing the fuel under the effect of pressurized flow (figure ).

Three factors drive the development of fuel injection systems: power, consumption and pollution.

The quantity of fuel, and therefore the power delivered by the engine, is determined by the injector flow rate, the injection time and the vaporization efficiency, which in turn depends on the size and speed of the drops created by the injector.