Patent GB-566694-A (GB)
Title: Improvements in or relating to fuel injection control gear for internal combustion engines
IPC: F02D1/00
Filed: 1943-03-02
Abstract: 566,694. Fuel - - injection systems. AMERY, M. [Representative of AMERY, G.], and AMERY HOLDINGS, Ltd. March 2, 1943, No. 3412. [Glass 7 (iii)] In a fuel-injection system comprising a spring-loaded relief valve for a positive-delivery fuel pump driven at a speed proportional to engine speed, the relief aperture of the valve opens gradually, affording a small aperture when the spring provides a low working pressure and an increasing aperture as spring pressure rises to a maximum which affords a high working pressure. The apparatus is identical with that described in Specification 566,693, and comprises a pump 11, Fig. 1 (Specification 566,693), drawing fuel from a tank 13 and delivering it continuously at injection pressure to injectors 15 ... 18 and, through a conduit 31, to an injection timing device or distributer 28 which permits injection when pressure is released in conduits 24 ... 27 leading to control pistons in the injectors 15 ... 18 by interrupting their communication with the conduit 31. When the engine is at rest, the return spring 68 of the accelerator pedal 65 urges an arm 63 of a bell-crank lever 61, 63 against the end 92 of a starting valve 108, Fig. 2, holding the valve on its seat 112 against fuel pressure applied through a narrow passage 111, a chamber 113 and a conduit 94 branched from the conduit 31. Simultaneously, the arm 61 of the bell-crank lever holds a vertical push-rod 47 in its lowest position. The rod 47 is slidable in and rotates with the shaft 38 of a conical cam 37 rotated by the shaft 50 of the pump 11. A cross-bar 45, rigid with the rod 47, engages at its ends in cam grooves 44 in a sleeve 43 secured by brackets 42 to a cam ring 39 in a groove in the cam 37. In the lowest position of the rod 47, a cam depression in the ring 39 is out of register with a similar depression in the cam 37 and adjustable conical rollers 36 on grooved tappets 35 hold open valves 32 to maintain communication between the conduit 31 and the control conduits 24 ... 27. When the engine is cranked or otherwise turned over, the fuel pump builds up pressure in the conduits 31, 94 and the chamber 113 until the starting valve 108 is displaced from its seat and rotates the bell-crank lever 61, 63, lifting the push-rod 47 to rotate the cam ring 39 relatively to the cam 37 and provide a narrow depression into which the rollers 36 drop to close in succession the valves 32, the closure cutting off the communication between the pressure conduit 31 and the particular control conduit 24 ... 27, whereupon the pressure in the control conduit is relieved through an axial passage 51 in the valve 32 normally closed by the tappet 35, and injection takes place. The pump 11 delivers an excess of fuel, the surplus being drained away past a relief device 71 comprising a cylindrical valve 99 adapted to close a passage 102 communicating with the pressure conduit 31. The passage 102 is narrow to ensure considerable pressure being necessary to open the valve in the first instance. Released fuel escapes along a tapered groove 105 in the valve, the escape aperture thus increasing with the displacement of the valve which is controlled by a spring 77 operating through a lever 75 of the first order. The pivot 76 of the lever is movable in a fixed slot 83 and in a slot 82 in the lever, being adjustably connected to an extension 85 of the bell-crank lever 61, 63. When the accelerator pedal 65 is depressed to widen the depression in the cams 37, 39, the leverage of the spring 77 on the valve 99 is increased and the fuel injection pressure rises. To stop the engine, a rod 98 is pulled to rotate a cam 118 which opens a valve 116 in the chamber 113, exposing the conduit 94 to a drain conduit and releasing all the pressure in the system. Specifications 442,532, 443,124, 443,356, 468,360, 468,372, [Group XXVIII], 501,588, 536,294, 546,598, 566,692 and 566,725 also are referred to.