Fuel temperature compensator for fuel injection pumps

Claim 1

In a fuel injection pump including a hydraulic head having a bore therein a plunger rotatably and slidably disposed within the bore, the bore end above the plunger comprising a fuel pumping chamber, means for providing a reciprocating and rotating motion of the plunger, means for delivering fuel to the fuel pumping chamber during a portion of the plunger cycle, delivery and distribution means for successively delivering fuel from the fuel pumping chamber to a plurality of pump outlet ports during compression strokes of the plunger, a passage in the plunger opening into the fuel pumping chamber and connecting the chamber with a spill port opening into a fuel sump in the hydraulic head, a fuel control sleeve slidably mounted on the plunger in the sump, and means for selectively adjusting the axial position of the sleeve, the improvement comprising a plurality of fuel control grooves in said sleeve adapted to cooperate with said spill port to control the opening of said spill port into said sump during each plunger compression stroke, each of said grooves terminating at its inner end adjacent said plunger in a control edge, said spill port passing across one of said groove control edges during each pumping stroke of the plunger, a temperaturesensitive compensator assembly in said hydraulic head bearing against said sleeve and adapted to vary the rotational disposition of said sleeve in accordance with variations in the temperature of fuel in the hydraulic head, said groove control edges being so related to the path of travel of said spill port as to vary the axial plunger position at spill port opening with variation in the rotational disposition of the sleeve whereby a change in fuel temperature effects a rotational repositioning of the sleeve to produce a compensating change in the pump fuel delivery, a rise in fuel temperature resulting in increased fuel delivery.