Patent ID: 6059545
Filing Date: 2000-05-09
Classification: F02M,F04B

Abstract:
A pump for a fuel injection system, the pump comprising:a pump body having a pumping chamber, a fuel inlet for supplying fuel to said pumping chamber, an output port, and a control valve chamber between said pumping chamber and said outlet port;a reciprocating plunger disposed in said pumping chamber, said plunger being reciprocatable over a stroke range between an extended position and a retracted position;an actuatable control valve assembly for controlling fuel, said control valve assembly being disposed in said control valve chamber, and said control valve assembly including a piston valve body axially movable over a motion displacement interval between first and second positions within said control valve chamber, said motion displacement interval being defined by first and second sub-intervals bounded by said first and second positions, respectively;an electromagnetic actuator for actuating said control valve assembly, wherein said piston valve body is urged toward an actuated position whenever said control valve is in an actuated state, said actuated position being one of said first and second positions, and a deactuated position being the other of said first and second positions;a valve stop disposed in said pump body adjacent said control valve chamber, said piston valve body contacting said valve stop whenever said piston valve body is in said second position;a first control valve spring positioned to cause said piston valve body to be biased toward said unactuated position whenever said piston valve body is in said first sub-interval; anda second control valve spring positioned to cause said piston valve body to be biased into damped engagement with said valve stop whenever said piston valve body is in said second sub-interval.