This fuel injection system used a high injection pressure under electronic control and a fuel delivery method known as a pilot injection that is electronically controlled by the electronic injection system via the injector (instead of being controlled by the injection pump as in previous direct injection engines).Pressure level is the basic parameter for optimising fuel consumption and exhaust fume levels.A pilot injection makes it possible to preheat the combustion chamber to avoid the pressure peak causd by rapid combustiojn and ensure smoother running.Injection pressure regulation is made possible by the constructional features of the system, which is equipped with separate pressure pump and injectors, both managed by a control unit. In this way, injection pressure is independent of engine rotation speed.
Performance
The main features of the fuel feed system are as follows:
high injection pressure (up to 1400 bars);
injection pressure modulable from 150 to 1400 bars under all engine service conditions
introduction of fuel up to 100 mm³/stroke within a speed range of 100 to 6000 rpm
precise injection control in terms of advance and duration
one or two pilot injections before TDC managed on the basis of rpm and engine load that allow pressure drift in the combustion chamber to be reduced to lower noise levels.