GB464760A - Improvements in carburetors for internal combustion engines - Google Patents

Abstract

464,760. Servomotors. BENDIX AVIATION CORPORATION. Sept. 16, 1935, Nos. 25716 and 25717. Convention dates, Sept. 17, 1934 and Nov. 7, 1934. [Class 135] [Also in Group XXVII] A carburetter comprises a main carburettitig passage and a throttle valve therein, an air choke valve controlling the air inlet to the main passage, a thermostatic control permitting or causing the opening of the choke valve as the temperature rises, an auxiliary mixture passage opening into the main passage beyond the throttle valve and containing an auxiliary valve urged to close by the suction beyond the throttle valve, and a control actuated by the choke valve to limit the closure of the auxiliary valve in accordance with the degree of opening of the choke valve, increased opening of the choke valve decreasing that of the auxiliary valve. A throttle valve 36 is byepassed by conduits 72, 78 communicating respectively with a chamber 68 through openings 74, 76 respectively which may be bridged by a reduced portion of a hollow piston valve 80 urged upwards by a spring 82. The interior of the valve 80 communicates through a small aperture 81 with the conduits and the suction thus transmitted draws down the valve to close, more or less, the opening 76. Within the valve 80 is a hollow plunger 86 linked to one arm 50 of a two armed member 50, 48 secured on the shaft 18 of an unbalanced choke valve 16. The piston 80 is drawn downwards until it uncovers a vent hole 90 in the plunger 86, the hole being lower as the choke valve 16 is opened by suction or otherwise. In its lowermost position, the valve 80 cuts off completely the passage 78. The action of the suction is modified by a thermostat 60, connected by a pin 56 engaged in the arm 48, which urges the valve 16 to the closed position when the engine is cold. An electric heater 66 may be used to actuate the thermostat. In operation a main nozzle 32 supplies fuel for starting and normal running As the engine fires, the conduit 78 is partly closed by the lowering of the valve 80 and an idling nozzle 42, supplied with air through a passage 44 in front of the throttle 38, comes into operation, the conduit 78 supplying mixture for fast idling. With the warmer engine, the thermostat 60 allows the choke valve to open and the valve 80 is correspondingly lowered, reducing the feed through the conduit 78. Fuel may be supplied to the chamber 68 by a conduit 92 connected either to the idling passage 40 or directly to the float chamber and the conduit 78 may be open into the atmosphere. In a modification, the valve 80 is omitted, the plunger 86 covering a series of ports in the chamber 68, and the connection of the plunger 86 to the choke valve permits the plunger to close the choke valve only. When twin throttle chambers are used, the plunger 161, Fig. 10, corresponding to the plunger 86, is connected by a member 151, formed as shown, to a bracket on the choke valve 116, the sector 153 closing the slot in the valve through which the member passes and the port 157 preventing the valve from opening beyond the fully open position.