GB1452680A - Power fuel supply system for an internal combustion engines carburettor - Google Patents

Abstract

1452680 Spray carburetters FORD MOTOR CO Ltd 20 Dec 1974 [7 Jan 1974] 55298/74 Heading F1H A power fuel supply for an I.C. engine carburetter 11 having at least two barrels 13, 15 and throttle valves pivotally mounted within the barrels, the carburetter including a fuel bowl 21, a power valve 67 adapted to receive fuel from the fuel bowl and discharge the fuel to first and second passages 98 and 99 which lead to the first and second barrels respectively, the power valve including a vacuum motor having a variable volume chamber which communicates with intake manifold vacuum through a passage 82 and a movable element 80 displaceable in response to intake manifold vacuum, the power valve also including a bore 89 and a piston 91 slidable within the bore, the piston having an inlet 96 communicating with an outlet openable to the first and second passages, the piston being movable to a first position in which it blocks the outlet to the fuel passages and isolates the first passage from the second passage, and being movable to a second position, shown in Fig.4, in which the outlet communicates with the first and second passages. When the absolute pressure in the intake manifold is high, spring 88 raises piston 91 against atmospheric pressure acting on the upper surface of diaphragm 80 and fuel flows through piston 91 at a rate controlled by the size of the orifice 101 in restrictor 65, which is biased by a spring 93 to close an opening 95 in the upper end of tubular portion 71. The apparatus also includes a mechanical connection between the throttle valve operating mechanism and the restrictor which moves the restrictor downwards during the latter part of the opening movement of the throttle valve so that there is unrestricted flow of fuel into the power valve and the rate of flow to the barrels is controlled by restrictors in the passages 98 and 99.