GB834970A - Improvements relating to fuel supply arrangements in internal combustion engine - Google Patents

Abstract

834,970. Fuel supply arrangements. GENERAL MOTORS CORPORATION. April 30, 1958 [May 9, 1957], No. 13726/58. Classes 7(3) and 7(6) An engine is supplied with fuel under normal operating conditions by an injector pump whose output varies with engine speed and which is connected to the output side of a transfer pump a movable valve member of a fuel metering valve controls the rate of fuel supply to the engine in accordance with the signal produced by air flow through a venturi in the engine air induction system and the valve member is moved under certain operating conditions from a position in which all the fuel that is supplied to the engine is delivered by the injector pump to a position in which fuel delivered by the transfer pump by-passes the injector pump and is supplied direct to the engine. As shown fuel outlet passages 64 are formed in the casing 34 and either communicate with a fuel manifold or as shown with the individual cylinder supply conduits 30. A set of radial passages 110 in the movable valve member 90 are adapted to register with annular port 84 but under normal operating conditions valve member 90 is maintained in the upper portion of the sleeve 38 whereby the radial passages 110 are out of registry with the annular sleeve port 84. Further the lower end 112 of the valve member coacts with the radial passages 66 to determine the quantity of fuel which is by-passed to the counterbore 68 and hence back to the reservoir 50. As air flow through the venturi 16 increases the lower end 112 of the valve member 90 increasingly reduces the quantity of fuel by-passed and hence increases the quantity of fuel delivered to the individual cylinder conduits 30. When the output of the main fuel supply pump 48 is very low as is the case when the engine is cranked preliminary to starting or under very low engine speed operation particularly when the engine is cold, the pressure within the sleeve 38 is very low. In this case the cranking vacuum acting on the diaphragm 26 is adapted to move the slidable valve member 90 downwardly to seat on stud 92 fully closing radial ports 66 and moving the radial passages 110 into registry with the annular port 84 Fuel from the make up pump 80 is then supplied to the interior of the sleeve 38 and thereby delivered to the outlet passage 64 and cylinder supply conduits 30. The force exerted on the top of the plunger 90 by the modulated vacuum signal imposed on the control diaphragm 26 varies with ambient temperature. Thus the plunger is not necessarily pushed down to seat on stud 92 to bring the passages 110 fully into register with the port 84. This permits the correct amount of fuel to enter the engine for starting at all temperatures. Fuel can thus be supplied from the transfer pump 80 when the injector pump 48 is being driven at speeds inadequate to supply the necessary quantity of fuel. The choke valve 20 is adapted to be controlled in response to engine temperature induction air flow and load.