Patent GB-590960-A (GB)
Title: Fuel and air supply systems of carburetting apparatus
IPC: F02M69/00
Filed: 1945-04-25
Abstract: 590,960. Carburetting-apparatus. BENDIX AVIATION COPORATION. April 25, 1945, No. 10415. Convention date, Sept. 21, 1944. [Classes 7 (iii) and 7 (vi)] In a fuel and air supply system a fuel-metering valve 36, which is controlled by an air vane 48, pivoted offcentre and opening against a spring in accordance with air flow, is combined with a fuel-supply valve 80, the opening of which is resisted by the pressure of fuel on its outlet side acting on a diaphragm 74 and assisted by the adjustable pressure of a spring 112. Fuel is supplied under constant but variable pressure preferably by a centrifugal pump having a bye-pass controlled by a spring-loaded valve, the supply pipe containing a vapour separating chamber, which includes a filter and is conected back to the fuel tank by a pipe containing a construction which permits pressure to build up in the chamber. The valve 80 is mounted in a casing divided into two chambers 76, 78 by the diaphragm 74, the chamber 78 being open to the atmosphere through a vent 79. Fuel enters the chamber 76 past the valve 80 seating on the inlet pipe 81 and is delivered through a pipe 32 past the spring- loaded valve 36 to a nozzle 34 which discharges in front of a spring-loaded shaft 50 carrying the vane 48. A cam 52 secured to the vane engages a roller 54 mounted on a lever 38 which actuates the fuel valve 36. The valve 80 has a resilient seating gasket 86 formed of neoprene or other material resistant to fuel, and a reduced stem 92, surrounded by a spring 98, which engages one end of a yoke 94 the other end of which is secured to the diaphragm. A screw 118 regulates the pressure of the fuel supplied to the nozzle 34 by adjusting the pressure of the spring 112 loading the diaphragm 74 and thereby controlling the closing force acting on the valve. An indicator may be provided to show the pressure at which the regulator is set and the screw 118 may be adjusted adjacent the regulator or from a distance, e.g., from the instrument panel by a rod or Bowden wire. To permit easier adjustment of the screws, the pressure on the spring retainer 114 may be counterbalanced by a spring whose tension can be adjusted by a screwed bushing. The screw may be replaced by a plunger 174, Fig. 11, having a head 178 on which the counter-balancing springs 112, 136 bear and the plunger can be actuated by a Bowden wire or as shown electromagnetically by a solenoid 170 which attracts an enlarged head 180 on closure of a switch 190. The head acts as a dashpot piston in the casing 172 and minimises oscillations of the plunger. In Fig. 12 the regulator is controlled by an arm 214 coupled by a rod 217 to an arm 204 loose on the throttle shaft and normally held by a spring 222 against a stop 224 to produce a lean mixture. When the throttle valve has been opened by a link 202 sufficiently for a screw 208 to engage the arm 204 further opening movement of the throttle will move the arm 214 to enrich the mixture. The valve 80 may be positioned in the carburetter casing adjacent the valve 36 and provided with a filter in front of the pipe 81.