GB1227755A - - Google Patents

Abstract

1,227,755. Fuel injection pumps. C.A.V. Ltd. Aug. 21, 1968 [Aug. 7, 1967], No.36129/67. Heading F1A. In a fuel injection pump in which the pistons 14, disposed in a bore 13 formed in a rotary distributer 10, are reciprocated through rollers 16 by engagement with the lobes of a cam 17, injection is terminated when a spill port 33, connected to a groove 32, communicates with a groove 31 in one piston to which pressurized fuel is passed via an axial passage 30 in the piston, the flow through the spill port 33 and a spill passage 35 being controlled by a valve 34. The fuel is supplied by a feed pump 51 the output of which is controlled by a valve 52 and passes through a passage 54, throttle controlled inlet port 25, inlet valves 56 and as the distributer rotates through an axial passage 18 in the distributer to the bore 13 thereby moving the pistons outward. On the delivery stroke, the output pressure moves a delivery valve 20 to the right and delivers fuel, via a delivery chamber 19, to an outlet passage 24, that registers in turn as the distributer rotates, with a number of outlets 24a and when the spill port 33 is uncovered, the valve 20 moves to the left and a predetermined amount of fuel flows back from the outlet 24 into the delivery chamber 19. In a modification, Fig. 3 the spill port 33 may be closed by a manually operated valve 36 to provide an excess amount of fuel for starting purposes. A piston 37, operable by the outlet pressure of the feed pump, may also be provided to adjust the spring-loading of the valve 34 in accordance with engine speed. The spring may be replaced by a peg 38 engaged by the piston 37.