GB1386191A - Fuel injection equipment including an hydraulic shuttle vlave - Google Patents

Abstract

1386191 Fuel injection pumps AMBAC INDUSTRIES Inc 23 Jan 1973 [24 Jan 1972] 3362/73 Heading F1A The delivery passage 54, Fig. 4, of a fuel injection pump 20 is alternately connected by a shuttle valve 58 to discharge passages 60, 62 leading to individual injection nozzles, the shuttle valve 58 being reciprocated in a bore 56 in synchronism with the pumping plunger 26 by fluid pressure acting alternately on its ends. Fluid is alternately supplied to and exhausted from each end of the bore 56 through a respective port 64a or 66a, Fig. 2, in a distributer porting plate 160, Fig. 3, and a passage connecting each port to the respective end of the bore 56. Each passage extends through a cover plate 84, the pump housing 76 and its side cover, a sleeve 98 supporting the pump barrel 28, a delivery valve holder 108 and a housing 52 containing the bore 56 for the shuttle 58. The ports 64a, 66a alternately register with arcuate high and low pressure/recesses 162, 164 in the lower gear 140 of a gear pump 138 which supplies fuel to the pump working chamber 106 during the suction stroke of the plunger 26. The recess 164 is in permanent communication with a drain and the recess 162 with the delivery passage 146 of the gear pump 138. To enable the gear pump 138 and distributer porting plate 160 to be removed for maintenance without disturbing the lobed cam 30 of the pump, the lower gear 140 has a stub shaft 148 splined to the cam shaft 32. A shaft 158 keyed to the upper gear 142 provides the input for a governor (not shown). Three constructional forms of shuttle valve 58 are described, two of which being operable to maintain pressure in whichever of the passages 60, 62 is not being supplied with fuel to be injected. In the embodiment shown, Fig. 7, this is achieved by a ball valve 192 disposed in an axial bore 184, 184b in the shuttle 58. Thus when actuating fuel is admitted to, say, the righthand end of the bore 56, the shuttle and the ball 92 move to their left positions shown. Accordingly, the pump delivery flows from passage 54, via an annular chamber 196, to the passage 62; at the same time pressure is prevented from collapsing in the passage 60 by the communication established by the ball valve 192 and ports 204 between the passage 60 and the righthand end of the bore 56. The quantity delivered by the plunger 26 is controlled in conventional manner by displacement of a rack 114 which controls the angular position of the plunger with respect to a spill port 126. By providing additional pumping plungers, each with an additional shuttle valve, further pairs of engine cylinders can be supplied with fuel.