Patent GB-646797-A (GB)
Title: Improvements in or relating to fuel supply systems for engines
IPC: F02D9/00
Filed: 1947-07-29
Abstract: 646,797. Regulating. BENDIX AVIATION CORPORATION. July 29, 1947, No. 20436. Convention date, Aug. 10, 1946. [Classes 7(iii) and 7(vi)] A fuel supply system comprises a pump 12 feeding fuel at constant pressure to a centrifugal impeller 39, the outlet 42 of which leads through a metering orifice 46 to a control valve 50 regulated by the pressure between the two orifices 86, 82 in a byepass 80 connected to the inlet and outlet sides of impeller 39. The orifice 86 is controlled by a valve 84 according to induction pipe pressure transmitted by a pipe 100 and acting on a diaphragm 87 which bears loosely against the stem of the valve 84 carried by a diaphragm 91 subject to unmetered fuel pressure in passage 42. A valve 150 is opened by a bi-metallic element 136 at low engine temperatures to allow fuel to byepass the orifice 46 through pipes 146, 147 and produce a rich starting mixture. The element 136 is situated in a chamber 132 through which air is drawn from a heater on the exhaust pipe, and it is connected to a rod 176 which controls a cam 168 co-acting with a stop 170' on the throttle actuating lever 164 to prevent complete closing of the throttle when the engine is cold. The lever 164 is connected to the throttle valve spindle 166 through a spring 180 which permits movement of lever 164 past the wide open throttle position, a pin on the lever then engaging a lug on the arm 176 so that the valve 150 is closed to allow excess fuel in the induction manifold to be swept away if flooding has been produced at starting. The pressure difference across orifice 86, for a constant position of the valve 84, is proportional to the square of engine speed, and hence, as the pressure in chamber 44 is maintained by the valve 50 equal to that in the byepass 80, the pressure drop across the orifice 46 is also proportional to square of engine speed. An accelerating device 105 is actuated by induction pipe pressure in pipe 100 to byepass fuel from the passage 42 to the pipe 60 connecting the metering system to a distributer 62 formed integral with the impeller 39 and comprising a radial duct 67, Fig. 2, which on rotation connects the pipe 60 successively to pipes 66 leading to spring-closed injectors 68 in the induction pipe 70. Each injector 68 feeds two cylinders and hence each pipe 66 is branched at the distributer 62 so that fuel is delivered twice in each revolution of disc 62 to each injector 68 in time with the intake of its respective cylinders. The pump 12, impeller 39 and distributer 62 are all driven by the shaft 14. The pressure in passage 42, acting on diaphragm 91, causes the valve 84 to open with increasing engine speed, thereby causing a reduction in the fuel supply which compensates for the reduced volumetric efficiency of the engine at high speeds. In a modification the valve 84 is controlled in accordance with throttle opening by a mechanical linkage which is arranged to produce a rich mixture at wide open throttle. The fuel supply may be corrected for changes in atmospheric pressure, and a supercharger may be included in the air intake. Reference has been directed by the Comptroller to Specifccation 662,835.