GB1154203A - Liquid Fuel Injection Pumping Apparatus - Google Patents

Abstract

1,154,203. Fuel injection pumps; rotary pumps. C.A.V. Ltd. Sept. 8, 1966, No. 38510/65. Headings F1A, F1B and F1F. In a fuel injection apparatus including a fuel injection pump 12, 13, 14 and a rotary distributer 11, the output of the injection pump is controlled by a spill valve having a rotary part driven at a higher speed than the distributer and a part which is fixed or capable of limited angular movement. A spill port is defined in one of the parts and is arranged to be covered by a land having an axially inclined edge driving part of the pumping stroke of the plungers 13. The parts are relatively axial movable to vary the timing of injection. In the embodiment shown, the rotary cylindrical member 32 having lands 39 is axially movable in the bore 30 having a spill port 40 by means of the output pressure of a feed pump 22 acting on its inner end in opposition to a spring 44. The loading on the spring 44 is adjustable by means of an operator adjustable member 45. The feed pump 22 has vanes 21 biased into contact with an eccentric stator ring 42 by the output pressure of the pump acting on their inner ends. Fuel is supplied to the injection pump via a chamber 8 in the distributer 11 and a non-return valve 27 and is delivered through passages 5 and 8 to outlet ports 19. To prevent pressurization of the fuel by the injection pump 12, 13, 14, the valve member of the valve 27 may be lifted from its seat. The delivery ports 20 may contain respective delivery valves or a single valve may be provided in the passage 18. The output pressure of the feed pump 22 is varied in accordance with the speed of rotation of the distributer 11 by means of a valve member 35, movable against the output pressure of the feed pump by means of a spring 36 and a pair of weights 37, controlling fuel flow from the pump outlet 23 back to the inlet 26. The rotary member 32 of the spill valve is driven by a cylindrical member 33 in helical gear engagement with the distributer drive member 16 and the member 33 is movable against the bias of a spring 34 by the output pressure of the feed pump 22 acting on its inner end to vary the timing of the member 32 relative to the distributer 11. The movement of the rotary member 32 by the spring 44 is limited by a rod 46 engaging the lever 43 and the surface of a spring- loaded piston 47 biased by the feed pump outlet pressure. The surface of the piston is inclined to its axis and a recess (47a, Fig. 3, not shown), is provided therein to provide excess fuel for starting. In a further embodiment, Figs.4 to 6 (not shown), the timing of injection is controlled by angularly adjusting a sleeve (50) in which the rotary member (52) operates by means of spring-biased piston (56) subject to the feed pump output pressure. The sleeve (50) is movable axially by a spring- biased piston (57) subject to the feed pump output pressure. In another embodiment, Figs.7 and 8 (not shown), the rotary part (70) of the spill valve is fixed axially and the timing is controlled by an axially and angularly adjustable sleeve (72). The sleeve (72) is biased to a maximum spill position by a spring (75) and an abutment (72a) on the sleeve abuts a pin (76) in engagement with a spring- baised piston (78) within a plunger (77). The movement of the piston (78) in the plunger (77) is restricted by a pin and slot connection. The plunger is subject at one end to the feed pump and at the other end to the force exerted by a lever (78) biased by an operator adjustable spring (80) to move the sleeve (72) against the bias of its biasing spring (75). The sleeve (72) is moved axially and angularly by a spring and feed pump outlet pressure biased piston (85) provided with a pin (89) to effect angular adjustment and a cam surface (92) engaged by a lever to effect axial movement. The cam surface may be shaped to provide excess fuel for starting.