Mechanisch betätigte hydraulisch verstärkte Brennstoffeinspritzvorrichtung mit elektronisch gesteuerter Druckentlastung

摘要

A fuel pump injector adapted for an internal combustion engine has a cam driven pumping mechanism 16, 26, a pressure intensifier mechanism 38, 46, an injection mechanism 60, and an electronically responsive relief valve mechanism (100, Fig. 2). The cam driven pumping mechanism has a pumping piston 26 operably reciprocating to pressurize a hydraulic fluid in a first pressure chamber 36 to a first pressure. The piston 38 of the pressure intensifier mechanism receives the hydraulic fluid at the first pressure from the pumping mechanism, and acts on the plunger 46 to pressurize fuel in a chamber 56 to a second pressure greater than the first pressure. The injection mechanism 60 receives the highly pressurized fuel from the intensifier mechanism. The injection mechanism includes a check 88 blocking an orifice 81 in an end portion of the injection mechanism. The pressurized fuel displaces the check away from the end of the injection orifice 81 to begin fuel injection. The relief valve mechanism is connected to the first pressure chamber 36 through a port 102 and operably exhausts the first pressure chamber in response to an electrical signal to end injection. <IMAGE>