Fast spill device for abruptly ending injection in a hydraulically actuated fuel injector

摘要

In a hydraulically actuated fuel injector, each injection event is initiated and terminated by opening an actuation fluid cavity within the injector to a high pressure inlet source and a low pressure drain, respectively. The present invention is intended to provide a more abrupt ending to each injection event in order to improve performance and exhaust emission quality. The present invention incorporates a hydraulically actuated spill valve into the injector body. The spill valve exploits the pressure differential existing between the fuel pressurization chamber of the injector toward the end of each injection and the drop in pressure in the actuation fluid cavity. This pressure differential is exploited to hydraulically open a spill port to allow the residual fuel pressure to dissipate into a fuel return passage rather than dribble out of the injector nozzle while the needle check is moving toward its closed position.