PUMP SYSTEM WITH HIGH PRESSURE RESTRICTION

摘要

A pumping system (10) for a fuel injection system (22) includes a body defining a high pressure pumping, a plunger, a high pressure outlet, a high pressure fluid line connecting the pumping chamber to the outlet, a control valve (20) along the fluid line, and a valve and restriction arrangement (15) along the fluid line. The valve and restriction arrangement (15) includes a restriction (16) and a valve body (18). The valve body (18) is movable between an open position in which fuel flow from the pumping chamber is generally unrestricted by the restriction and a closed position in which fuel flow from the pumping chamber is significantly restricted by the restriction to store energy in the pumping chamber. Advantageously, the high pressure restriction concept may be utilized in a pumping system for various types of rate shaping, including boot injection and square injection, in addition to pilot operation and post injection operations, and others.