GB1322538A - Fuel injection pumps for internal combustion engines - Google Patents

Abstract

1322538 Fuel injection pumps ROTO-DIESEL 10 July 1970 [10 July 1969] 33575/70 Heading F1A In a fuel injection pump comprising radial pistons reciprocated in cylinders in a rotary distributor 3, a radial spill port 13a in an axially adjustable ring 13 co-operates with radial passages 40 connected to the pumping chamber to control delivery. The ring 13 is urged to the left (delivery increase) by springs 36 to a position abutting a stop 16x on a bell crank lever 16. At start-up the lever 16 positions the ring 13 so that no spillage occurs. With increasing speed, a feed pump 1 builds up pressure to lift a piston push-rod 12 and rotate the bell crank, and thus move the ring 13 to the right. An adjustable spring loaded plunger 30 bears on the lever 16 to modify the spring force due to the springs 36. The stop 16x thus determines the maximum fuel delivery for all speeds. Axial adjustment of the ring 13 is also effected by a sleeve 24a urged to the right by flyweights 24 and to the left by a spring 25 acting through a lever 26. The tension in the spring 25 is a function of the accelerator setting of the associated engine. Fuel enters the pumping chamber during the suction stroke through one of the radial passages 9 aligning with a passage 6 fed by the feed pump 1. During the delivery stroke a radial passage 8a aligns with one of the delivery ducts 22 leading to the injectors. A device 15 automatically rotates a cam ring operating the pistons to effect a change in the timing. The ring 13 is rotated by a similar amount since it slides on guides 37 fixed to the cam ring. This rotation may cause simultaneous axial adjustment of the ring 13 if a cam surface is provided on the ring 13 where it contacts the stop 16x, Figs. 13 and 14 (not shown). In the event of the ring 13 seizing to the rotary distributor 3, an auxiliary chamber (45) radially extending from the ring 13 and in constant communication with the pumping chamber is caused to be broken off, so that pump pressure is lost. The radial passages 40 may be arranged to co-operate with a spill slot (136), Fig. 15 (not shown) in the ring 13 thereby to produce a twostage injection.