Fuel pumping apparatus

Claim 1

A liquid fuel injection pumping apparatus comprising a rotary distributor member mounted in a body, a radial plunger bore in the distributor member and a pumping plunger in the bore, a cam follower located at the outer end of the plunger and engageable in turn with a plurality of cam lobes formed on the internal peripheral surface of an annular cam ring, the cam lobes having leading flanks which impart inward movement to the pumping plunger as the distributor member rotates and trailing flanks which allow outward movement of the pumping plunger, a plurality of outlet ports formed in the body, passage means in the distributor member which connect the bore to the outlet ports in turn during successive inward movements of the pumping plunger, fuel supply means for feeding fuel to the bore in the intervals between inward movements of the pumping plunger thereby to move the pumping plunger outwardly its maximum extent and adjustable valve means operable to spill fuel from the bore during the inward movement of the pumping plunger to terminate delivery of fuel, thereby to control the quantity of fuel delivered through the outlet ports, a piston slidable in a cylinder formed in a part associated and rotatable with the distributor member, resilient means biasing the piston towards one end of the cylinder, a passage in the distributor member which connects the one end of the cylinder with the bore and a stop to limit the movement of the piston, the piston acting to absorb the fuel expelled from the bore during the initial inward movement of the pumping plunger.