Patent GB-625829-A (GB)
Title: Improvements in or relating to fuel control systems for internal combustion engines
IPC: F02M69/00
Filed: 1946-08-09
Abstract: 625,829. Regulating. CHANDLER EVANS CORPORATION. Aug. 9, 1946, Nos. 23659, 23660, 23661 and 23662. Convention dates, Aug. 17, 1945, Sept. 24, 1945, Dec. 1, 1945 and Jan. 16, 1946. [Classes 7 (iii) and 7 (vi)] A fuel regulating system comprises a fuel pump 56 delivering through a control valve 64 and a metering unit 66 to an orifice 70 controlled by a rotating piston 42 subject to the pressure drop across the metering unit and connected to a diaphragm 22 subject to the pressure differential across a venturi 10 in the air intake, the fuel flowing from a chamber 106 through a rotary distributer 94 to fuel injectors 120 in the engine cylinders or their intake passages. The metering unit 66 comprises two orifices 80, 82, fed by a pipe 76, and a rich mixture orifice 88 controlled by the valve 64. The metered and unmetered fuel pressures acting on the piston 42 balance the air pressure differential on the diaphragm 22, a capsule 38 correcting this differential for altitude and temperature, and the fuel flow is thus proportional to the mass air flow. The distributer 92. comprises a spring-pressed piston 94 rotated by a shaft 98 and having a groove 108 connecting in succession orifices 110, 112 leading to the injectors with the metered fuel space 106, the fuel pressure in which, controlled by the valve 42, controls the amount of fuel injected. Removable orifices 142 in the pipe 114 permit adjustment of the fuel delivered to the individual injectors. The valve 42 is continuously rotated, to prevent sticking from the shaft 98 through a square rod 102 which permits axial displacement of the valve, and the diaphragm 22 is biased by a spring 25 for a slow-running adjustment. In Fig. 2 the diaphragm 306, subject to the venturi air-pressure differential, acts directly through a ball-bearing connection 324 on the distributer 252 which is rotated from the shaft 220 of a rotary pump 216 through gearing 256 allowing axial movement of the piston 252. The pump 216, having a spring-loaded bye-pass valve 230, delivers fuel through the control valve 64 and metering unit 66 of Fig. 1 to a pipe 270 and space 274, from which the fuel is distributed by a groove 276 to the conduits 278 leading to the injectors. A pipe 262 connects the space 264 to the unmetered side of the metering unit, the piston being moved axially by the fuel-pressure differential in chambers 264, 274 against the air-pressure differential on diaphragm 306 to control the flow to the conduits 278. A resilient flap 248 allows fuel to be forced through the bye-pass valve 230 if the pump 216 seizes when in series with another pump. In Figs. 7 and 8 the piston 430, subjected directly to the delivery pressure in the chamber 422 of the pump 412, and to the metered fuel pressure through a pipe 468, controls orifices 534 by-passing fuel back to the suction side of the pump through a 'conduit 530. The fuel flows from the pump through a pipe 440 to the metering unit 444 and through a diaphragmactuated valve 482 to a spraying tube 450 in the air intake passage. In a further modification the metering unit is omitted and the fuel flows from the pump through a fixed orifice to an annular chamber connected by a groove in the piston to the fuel injection passages, the right-hand side of the piston controlling the bye-passing of fuel to the pump inlet as in Fig. 7. Reference has been directed bv the Comptroller to Specification 639,923.