Patent GB-973769-A (GB)
Title: Fuel pump and distributing apparatus
Inventor: CUMMINS CLESSIE LYLE
IPC: F02M59/00
Filed: 1962-12-04
Abstract: 973,769. Regulating I.C. engines. C. L. CUMMINS. Dec. 4, 1962, No. 45790/62. Heading F1B. In a compression-ignition engine fuel system having a metering piston 33, Fig. 1, in the bore of a housing with ported end chambers 60, 48 which are alternately charged with fuel to move the metering piston and thereby discharge fuel from the opposite chamber, a manually controlled throttle 88 having a cam face 87 is operatively engageable with one end of the metering piston to limit movement of the metering piston in one direction, a cam groove 90 limits movement in the other direction and speed responsive means 47 reduces the fuel delivered at predetermined engine speeds regardless of the position of the cam face 87. Fuel from pump 23 flows through conduit 28, filter 30 to pressure regulator 31 from which spill-off passes through lines 32, 22 to the suction side of pump 23. From regulator 31, fuel passes through conduit 35, electric solenoid shut down valve 36, branching conduit 37 to ports 38, 40 at rotor 41 which is turning at crank-shaft speed to allow fuel alternately to the ends of metering piston 33 which moves to direct fuel either to injectors 34 or back to the suction side of pump 23. Conduit 42 in rotor 41 is indexed with ports 40, 43 to pass fuel into branching conduit 44 through groove 46 in governor plunger 47 and thence to chamber 48, causing the metering piston 33 to be moved downwardly. Fuel present in chamber 60 is displaced through passages 57, groove 58 and passages 57, 55, 61 and 63 to the injectors 34. When the rotor is indexed through 90 degrees fuel under pressure from pump 23 enters chamber 60 to force the metering piston upwards thus recharging chamber 60. Each pair of injectors 34 is arranged so that one of each pair is closed off by its operating cam and will not accept a charge of fuel at the time that the other injector of the pair is ready to be charged. In a modification the rotor 41 is arranged for a six-cylinder engine. The volume of the fuel charge is adjusted by rotating throttle shaft 88 so that cam 87 acts either directly or through a tappet 91 to vary the stroke of the metering piston 33. A tamper-proof seal may be incorporated in the retainer of shaft 88. As engine speed increases the action of the governor weights moves plunger 47 which may rotate with the governor weight to the right to compress spring 94. Idling and coasting. When the throttle 88, Fig. 4, is in the idling or coasting position ports 95 and 96 are connected by passage 97, the amount of fuel spill-off is controlled by plunger 47 through the position of groove 98 in relation to port 100 by which the chamber 60 is connected with the suction side of the pump 23. Overspeeding. When the speed is above the maximum governed speed plunger 47 moves to the right and shoulder 106 cuts off ports 107 and 108 to create a hydrostatic block in metering chamber 60. Overloading control. If speed decrease due to increased load when the throttle is fully open plunger 47 moves to the left and end 112 of tappet 92 rides up the cam groove 90 thus shortening the metering piston stroke. In a modification, the functions of idle speed, overloading control and overspeed are controlled by a multi-tapered shoulder in the plunger 47. Injector lubrication. Fuel is carried from the fuel pump to a scavenge groove 125, Fig. 8, on injector plunger 72 by means of which the plunger is lubricated during coasting and air working up between the plunger and wall 73 is carried back to the fuel tank. In a further embodiment a rotor-plunger 160, Fig. 10, which is axially positioned by the governor distributes pressure fuel to the chambers 60 and 48 causing metering piston 33 to pump a fuel charge at each stroke and a rotor 161 distributes fuel to single injectors or pairs of injectors which are not 360 degrees apart in firing order. A modification of the distributer 177 suitable for six-cylinder engines is described. In a modification, overloading in the lower speed ranges under maximum throttle/ full load condition is prevented by spilling-off part of the fuel charge through ports 194, 195 and rotor groove 193, Fig. 17.