GB1368526A - Fuel injection pump assembly - Google Patents

Abstract

1368526 Fuel injection pumps FORD MOTOR CO Ltd 18 Oct 1972 [15 Nov 1971] 47880/72 Heading F1A In a fuel injection pump comprising a plurality of pumping plungers 50 each reciprocable in a cylinder 52 and each delivering to an individual engine cylinder past a delivery valve 59, some of the plungers are prevented from reciprocating when the engine idles or is lightly loaded. The plungers 50 are reciprocated by an inclined drive plate 34 integral with a drive-shaft 32 for coupling to the engine. Each plunger capable of being prevented from reciprocating (each alternate one in the embodiment described) is provided with a circumferential groove 146 into which a ball 142 is urged when movement thereof is to be prevented. Each ball 142 if forced into its respective groove 146 by a fluid activated spool 148 under the control of a rotary valve 164. Each valve 164 connects opposite ends of its respective spool to engine oil pressure and low-pressure. At idling or low load the upper spool ends are at low-pressure and the plungers are held in the inoperative position shown. When idling speed or a predetermined load is exceeded a microswitch 133, Fig.3, under the control of the engine accelerator linkage causes de-energization of a solenoid (180), thereby to release a spring (186) to cause rotation of a ring gear 174. The ring gear 174 is in mesh with pinions 172 of the valves 164, whereby the latter are rotated through 90 degrees. This causes the spools 148 to move to their downward positions in which they release the plungers 50. Pump delivery and timing are controlled by a centrally located rotatable sleeve valve 70 having a helical control edge 78 which controls communication between an inlet passage 62, 64 and each port 58 leading to a cylinder 52. The sleeve valve 70 is both axially and angularly adjustable with respect to an extension 82 of the drive-shaft 32, the extension 82 itself being axially movable by the engines accelerator linkage 128, 130, 131, 96, 95, 94. A centrifugal governor 91 mounted on the extension 82 acts via a thrust bearing 104 and a sleeve 100 to control the position of the sleeve valve 70. Below the speed at which injection advance is required (about 2, 400 r.p.m.) a spring 114 maintains the sleeve valve 70 and sleeve 100 separated. When this speed is exceeded, the sleeve 100 is moved downwardly by the centrifugal governor whereby a pin 108 on the extension 82 enters an inclined slot 112 in the sleeve 100 thus causing rotation of the sleeve valve 70 splined thereto to effect a change in the timing. At start up the accelerator linkage is moved to a position which fully raises the extension 82, whereby almost the maximum delivery is injected. Immediately the engine starts the linkage is moved to a position which returns the extension 82 to its lowermost position. Simultaneously, however, the governor 91 overcomes the action of a spring 97 whereby the sleeve valve is established in its idle speed position. On further lifting of the extension 82, a point is reached in which the spring 97 is fully compressed by the governor and the extension 82 and sleeve valve 70 move together. Further movement of the extension 82 increases engine speed (to say 2, 400 r.p.m.), at which speed the governor becomes effective to compress the spring 114 and effect a timing change as previously described.