Patent GB-551125-A (GB)
Title: Improvement in charge forming device for internal combustion engines
IPC: F02D9/00
Filed: 1941-08-05
Abstract: 551,125. Spray carburetters. BENDIX AVIATION CORPORATION. Aug. 5, 1941, No. 9956. Convention date, Aug. 3, 1940. [Class 7 (iii)] A carburetter of the closed fuel system type is made up of parts which may be separately tested and assembled comprising a body portion A embodying two air intakes 10 side-by-side fitted with throttles 12 ; a fuel regulator unit C attached thereto by bolts 112 and comprising diaphragms 93, 95 controlling a fuel-inlet valve 79 in accordance with the air flow in the intakes and the flow of fuel ; a fuel control unit D attached to flanges 129, 131 on the unit C and controlling the richness of the mixture. An adaptor section E may also be provided which carries the fuel nozzle 204 and is bolted between the body A and the induction pipe, while a further unit B comprising a valve 47 actuated by a capsule 45 maintains a constant richness of mixture for changes of altitude and temperature. The chamber 119 at the right of the diaphragm 93 is connected to a passage 39 which is subjected by passages 36, 37 to the pressure in small Venturis 35 mounted within the two main Venturis 17, while the chamber 120 to the left of diaphragm 93 is subjected to the pressure in the intakes 10 conveyed by pipes 19 to chambers 18, which are connected by passages 21, 22, 23 to a passage 24 leading to the chamber 120, the valve 47 modifying the differential pressures on the diaphragm 93. Fuel is supplied at 59 and passes through a port 69 and past the valve 79 to the chamber 117 at the right side of the diaphragm 95. From there it flows to a passage 127 leading to a chamber 160 having a metering-orifice 161, through which the fuel passes to a passage 163, chamber 164, and outlet 151 connected by a pipe 152 to the valve-controlled nozzle 204. The fuel pressure at the right-hand side of the metering-orifice 161 is conveyed past a valve 172 to a passage 134 leading to the chamber 118 at the left of the diaphragm 95. A further metering-orifice 175 leads to an economizer valve 183 connected to a diaphragm 186 subjected at the left-hand side to the fuel pressure in the passage 163, and at the right-hand side to the fuel pressure in the passages 127, 130. A third metering- orifice 178 comes into action when the valve 183 is closed and passes fuel to a passage 177. The passages 130, 163 and 177 and a further passage 166 are controlled by a manually-actuated rotary disc valve 165, Figs, 3 and 5, which closes all the passages when the engine is stopped. In the automatic-lean position shown in Fig. 5, only the passage 177 is closed, and fuel passes through the metering-orifice 161 to the nozzle 204, the flow of fuel being controlled by the diaphragms 93, 95 and a spring 99 acting on the valve 79, and also by a needle valve 153 in the passage 127 actuated bv an arm 154 connected to the throttles 12. In the automatic-rich position of the valve 165, the passage 177 is also open, and the engine receives fuel through all the metering-jets 161, 175, 178, the valve 183 being closed. Additional richness may be obtained in emergency at altitude, by further movement of the valve 165 which, while still retaining all the passages therethrough open, also opens a valve 26 which byepasses the altitude control valve 47. A vent 65 for fuel vapour is controlled by a float valve 66 and vapour which collects in the top of chambers 117, 118 escapes through the passages 130, 136. Fuel leaking into the chambers 119, 120, or water or rain entering chamber 120 from the tubes 19, drains away by passages 39, 38 and by a small passage 141 connecting the two chambers. The control unit D may be tested before being secured to the carburetter, by supplying fuel at a constant pressure at 127, and ascertaining the rate of flow through the unit with the lever 169 in each of its several positions. The unit D is then bolted to the unit C and the combination tested by applying suction, e.g. by a vacuum pump, to the chamber 119 to an amount measured by a manometer, and by supplying fuel to the regulator C and to a test discharge nozzle fitted at 151, the fuel flow being obtained by a meter and the air flow from the manometer reading and calibration curves for the Venturis. Specifications 520;441, 523,895, 536,622, and 541,084 are referred to.