Abstract: 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 that can be calibrated outside of the injector prior to the installation thereof.

Abstract: A fuel injector for periodically injecting fuel pulses of a variable quantity on a cycle to cycle basis as a function of the pressure of fuel supplied to the injector from a source of fuel and at a constant time during each cycle is set forth including an injector body containing a central bore and an injection orifice at the lower end of the body and a reciprocating plunger assembly including an upper plunger section and a lower plunger section serially mounted within the central bore to define a variable volume metering chamber located between the lower plunger section and the lower end of the injector body containing the injection orifice. The variable volume metering chamber communicates during a portion of each injector cycle with the source of fuel.

Abstract: A variable displacement high pressure pump having a plurality of high pressure pumping units which receive fuel from a low pressure fuel pump. A rotary cam-driven roller tappet, for producing pumping displacement of the pumping plunger of a respective pumping element, is connected to the pumping plunger by a separated link in a manner permitting the pumping plunger to float relative to the roller tappet during at least a portion of each pumping cycle. As a result, the capacity of the pumping chamber can be limited to an extent that is less than the full stroke achievable by the pumping plunger being retracted to the maximum extent which is permitted by the driving cam.