GB1362129A - Diaphragm carburetors - Google Patents

Abstract

1362129 Spray carburetters WALBRO CORP 10 Nov 1972 [9 Dec 1971] 51956/72 Heading F1B A carburetter comprises a fuel inlet control valve 30, Fig. 1 controlled by a diaphragm 40 in a chamber 42 from which fuel passes to a mixing passage 12 Fig. 2 through a main fuel duct 16 or an idle fuel passage, the main fuel duct has a double flow path between an opening 104 and the main fuel nozzle, one flow path has a fuel metering nozzle 7 and the other flow path has a check valve 94 which either prevents reverse flow from the mixing passage or prevents flow through the other flow path or allows flow through both flow paths. In operation a pump diaphragm 20 supplies fuel via filter 24, passage 28 and valve 30 to chamber 42. When throttle 56 is wide open check valve flap 94 closes opening 72 and when the throttle is closed the flap closes opening 104 to prevent fuel blow back from the mixing passage through the idle passages which are fed from chamber 42 via passages 62, Fig. 5, 66 and 54. Passages 58, 60 may serve as air inlets for the idle mixture in the closed throttle position. When the throttle is being moved from the closed to the open position the flap 94 occupies an intermediate position in which both flow paths are fed with fuel from a reserve supply of fuel in the chamber 82 thereby assisting engine acceleration.