FUEL INJECTOR WITH NEEDLE CONTROL SYSTEM THAT INCLUDES F, A. Z AND E ORIFICES

摘要

A common rail fuel injector (10) includes a needle valve member (30) that moves to open and close nozzle outlets (45) for a fuel injection event responsive to pressure in a needle control chamber (52). Between injection events, the needle control chamber (52) is fluidly connected to the fuel inlet (44) by a first pathway (61) that includes a Z orifice (66), and fluidly connected to the fuel inlet (44) by a second pathway (62) that includes an F orifice (68), an intermediate chamber (54) and an A orifice (67). During an injection event, the needle control chamber (52) is fluidly connected to a drain outlet (46) by a third pathway (63) that includes the A orifice (67), the intermediate chamber (54) and an E orifice (69). Different performance characteristics are achieved by adjusting the throttle sizes of the respective ofF, A, Z and E orifices (66, 67, 68, 69).