GB810650A - Improvements in or relating to fuel injection systems for internal combustion engines - Google Patents

Abstract

810,650. Spray carburetters. GENERAL MOTORS CORPORATION. Aug. 19, 1957 [Sept. 10, 1956(2)], No. 26085/57. Class 7(3) In a carburetter 46 comprising a fuel pump 54, Fig. 3, delivering to a metering mechanism 60 from which the fuel is distributed through pipes 82 to nozzles 84, Fig. 1, in the intake pipes, a device 104 cuts off the supply of fuel to the nozzles when the throttle valve is shut during overrunning. The pump 54 is situated in a float chamber 44 and the cut-off device 104 comprises a normally closed by-pass valve in the pump delivery pipe 56 which is opened at overrunning by the intake manifold vacuum acting upon diaphragm 108. The suction connection 116 from the diaphragm chamber 112 is connected to passages 118, 120, Fig. 1, leading respectively to the upstream and downstream side of the throttle valve 42. During overrunning with the throttle valve partly open the flow of air through passage 118 reduces the suction in passage 120 acting on diaphragm 108 and prevents opening of the valve 104. On closing of the throttle valve, a pad 124 thereon closes passage 118 and the high intake manifold suction during overrunning opens valve 104 to by pass the pump delivery back to the float chamber 44. During normal operation the fuel from pump 54 flows through a check valve 74 to a distributing space 76 in which the pressure and hence the supply to the nozzles 84 is controlled in accordance with air flow by a spill valve 80 controlled by a diaphragm 90 responsive to the suction in the air intake pipe 34. The carburetter 46 is located in the space between the cylinder banks 32 of a V-engine and is contained within a housing 22 through which air flows to the carburetter air inlet pipe 34, cooling the float chamber 44.