Fuel pumping apparatus

Claim 1

A fuel pumping apparatus for supplying fuel to a compression ignition internal combustion engine, and comprising an injection pump operable in use in timed relationship with an associated engine, a pump for supplying fluid at a pressure which varies with the speed at which the apparatus is driven, a cylinder, a fluid pressure operable piston in the cylinder, said piston being responsive to the pressure of said fluid to vary the timing of delivery of fuel by the apparatus such that with increasing speed the timing of delivery of fuel is advanced, an end closure for the cylinder, resilient means biasing the piston in a direction away from said end closure, said piston being moved against the action of said resilient means to advance the timing of delivery of fuel by the injection pump, a shaft mounted in said end closure for angular movement about the axis of said cylinder, a lever mounted on said shaft and operable in use when it is required to start the associated engine, to move the shaft from an inoperative position to an operative position, said shaft having a hollow end portion presented to the piston and defining a pair of axially extending slots, an actuating rod having one end located within said hollow end portion and mounting an abutment which acts as a stop to determine the extent of movement of the piston under the action of the resilient means, a pin mounted in said actuating rod for engagement by the walls of said slots, an annular member surrounding the hollow end portion of the shaft, said member defining a pair of cam profiles for engagement by the opposite end portions of the pin, each cam profile defining three settings for the pin, the first of which is a normal running position, the second of which is the cold start position in which the piston is allowed to move to a position in which the timing is retarded as compared with the normal running position, and a third setting in which the piston is allowed to move to a position in which the timing is advanced as compared with the normal running positions, said pin being moved from said first position to the second position when the shaft is moved from the inoperative to the operative position, the pin being moved at least in part by further resilient means from said second position to said third position when the piston is subjected to fluid pressure.