Patent GB-628924-A (GB)
Title: Charge forming device or carburet or for internal-combustion engines
IPC: F02M69/00
Filed: 1947-07-31
Abstract: 628,924. Spray-carburetters. BENDIX AVIATION CORPORATION. July 31, 1947, No. 20844. Convention date, Sept. 13, 1946. [Class 7 (iii)] In a fuel supply system including a valve 46 controlled by diaphragms 42, 34 subject respectively to the pressure drop across the fuel metering system 71 and to the air pressure differential at a Venturi 19, an idling valve 91, in parallel with the valve 46, by-passes idling fuel through a passage 102 containing a restriction 103. The fuel, supplied at 57 by a pump, flows through a filter 33, valve 46, and passage 70, to the metering system 71 and thence through pipes 81, 811 to a fuel injection nozzle 29. The pressure drop across the idling metering restriction 103 is maintained constant by an adjustably spring- loaded diaphragm 94 carrying the idling valve 91, and the idling flow is controlled by a slot 104, Fig. 6, in a plate 105 on a shaft 108 which is rotated by linkage in accordance with the opening of the throttle valve 27. When the throttle is open the slot 104 is out of register with the orifice 106, cutting off flow through the idling passage 102, and a second slot 1101 in the plate 105 registers with a passage 111<SP>1</SP> and vents a chamber 112 to the passage 70, allowing free movement of the valve 46. As the throttle valve 27 is closed the slot 104 begins to register with orifice 106 at or near idling and the slot 1101 goes out of register with passage 111<SP>1</SP>, sealing the chamber 112. A restriction 113 then allows the pressure from the fuel entry passage 58 to build up in chamber 112 and keep the valve 46 closed. The slot 104 may be a plain slot or contoured as shown, the part 1041 giving an increasing idling flow while valve 46 is held closed, and the part 104<SP>11</SP> allowed a small flow through by-pass 102 after the 'slot 110<SP>1</SP> has registered with passage 111<SP>1</SP> and valve 46 has begun to open. The air pressure differential on diaphragm 34 is corrected for density variation by a capsule operated valve 15 and the metering system, in addition to the metering jets 72, 73, 74, includes a power enrichment jet 78 operated by a diaphragm 79 subjected to unmetered and metered fuel pressures, a derichment jet 75 controlld by a valve 77 which closes on operation of an anti-detonant metering device, and a manual control valve 82 comprising a series of coacting ported valve-plates. The fuel inlet chamber 56 is provided with float controlled valves 65 venting vapour through a pipe 67 back to the fuel tank. An accelerating pump 30 operates on opening of the throttle valve to force fuel through pipes 32, 321 to increase the pressure in a chamber 52 acting on a diaphragm 49 and open the valve 46 to increase temporarily the fuel flow. In a modification, Fig. 7, the spring 1001 loading the diaphragm 94 carrying the idling valve 91 is adjusted by an abutment 1381 connected to a lever 129 pivoted, at 137 and controlled by bellows 125, 131 responsive respectively to the temperature and pressure of the intake air. The diaphragm 94 may alternatively be controlled according to air flow or fuel flow. Specification 523,895 is referred to.