FUEL METERING CHECK VALVE ARRANGEMENT FOR A TIME-PRESSURE CONTROLLED UNIT FUEL INJECTOR

摘要

Check valves (500) are incorporated into a fuel injector so as to form a controlling orifice in the system between the solenoid vales which direct fuel to the respective injection and timing chambers of the fuel injector and the chambers themselves. The precision fuel metering capability of the valve (500) is determined by an annular clearance created between the plunger (512) of the valve and the valve body (510) when the valve is in its maximum stroke. For achieving a bi-stable operation of the valve, the ratio of the plunger valve seat (510d) area to the maximum plunger valve (512b) area and the spring (514) are key parameters. The check valves (500) are formed as cartridge type check valves taht can be calibrated outside of the injector prior to the installation thereof.