Fuel Injector: Description and Operation

INJECTORS





DESCRIPTION

Each fuel injector contains a needle valve rigidly attached to the plunger of a solenoid which, when energised by an electrical pulse, moves the needle away from its seat against a helical pressure spring. This action permits a measured quantity of pressurised fuel to enter the inlet manifold, via an integral filter and nozzle, each time an injector pulse is applied.

Valve lift is approximately 0.15 mm (0.006 in.) for the fully open position which is reached in a response time of approximately 1 millisecond. The amount of fuel delivered is dependent only on the period of time the injector is open, the precise open time being determined by the ECU and is typically 2.75 milliseconds at engine idle.