Method and apparatus for rate shaping injection in a hydraulically-actuated electronically controlled fuel injector

摘要

A hydraulically-actuated electronically-controlled fuel injection system includes a solenoid operated main valve that controls the flow of actuating fluid to the individual injectors. The flow of pressurized actuating fluid pressurizes the fuel and causes injection to occur. The present invention accomplishes pilot injection and/or other injection rate shaping by constricting the flow of pressurized actuating fluid to the piston pump chamber of the individual injectors during a portion of each injection cycle. Constricting the flow of pressurized actuating fluid is accomplished by a separately controlled solenoid valve preferably positioned between the actuating fluid manifold and the main control valves of each individual injector.