GB1080311A - Improvements in or relating to fuel injection apparatus - Google Patents

Abstract

1,080,311. Fuel injection pumps. W. FRIEDLANDER. Jan. 31, 1964 [Nov. 1, 1962], No.41375/62. Heading F1A. A fuel injection pump comprises a housing 10, a pumping chamber 12 which receives a governed amount of low pressure fuel, a first reciprocating member 39a which pumps the fuel to an injection nozzle 20, and a second reciprocating member 39b separated from the member 39a by hydralic fluid such that reciprocation of the second member causes reciprocation of the first member. A low pressure fuel feeding device 21 and the injection pumps are actuated from a common cam-shaft 42. A plunger 46 of the device 21 supplies fuel to the injector pumps through a conduit 22 and a collar 47 on the plunger supplies fuel to a chamber 29, in which is located a governor valve 28. As the fuel pressure builds up, the valve 28 moves until a reduced diameter portion 30 interconnects conduits 27, 31, thereby opening a by-pass circuit. The angular setting of a peripheral cut-away portion 37 on the valve 28 relative to a return conduit 48 determines the rate at which fuel flows to the conduit. The cut away 37 varies in radial depth around the valve circumference and its setting is adjusted by a lever 38. A gear pump 81 supplies hydraulic fluid to a space 61 between the members 39a, 39b of the injection pump plunger 11. The member 39b is actuated by a cam 19 and injection is terminated when the member 39a uncovers a by-pass passage 86. A relief valve 85 maintains a constant pressure in the hydraulic circuit thereby keeping the member 39b in contact with the cam 19 and hence maintaining the injection timing constant. Alternatively the relief valve 85 may be replaced by a restriction (89) so that the pressure is proportional to engine speed and by having to overcome a spring (98a) acting on the member (39b) injection timing is progressively advanced as the engine speed increases, Fig. 3 (not shown). In a preferred embodiment of the pump 9, the member (39b) is replaced by a cap (17a) which slides over the pump barrel (10) and is directly acted upon by the cam, Figs. 4, 5 (not shown).