FUEL INJECTOR AND METHOD OF ELECTRONICALLY OPERATING A FUEL INJECTOR

摘要

A fuel injector (10) is provided for each cylinder of an internal combustion engine, the injector including an electronically operated control valve (146) disposed between supply passage (42) and a timing chamber (98) to control the admission of fuel into and out of the timing chamber. A primary pumping plunger (62) and a secondary plunger (90) are axially spaced within the central bore of the injection body, and a normally closed injection nozzle (14) is situated at one end of the injector body. A mechanical linkage (30) associated with the cam-shaft of the engine drives the primary pumping plunger (62) against the bias of a main spring (18). The timing chamber (98) is defined between the plungers (62, 90) and a metering chamber (128) is defined between the secondary plunger (90) and the nozzle (14). An electronic control unit responds to engine operating conditions, and delivers a timing and metering signal to the control valve (146) to close the valve and seal the timing chamber for a controlled period of time.