GB826331A - Improvements in or relating to apparatus for forming the combustible charge for internal combustion engines - Google Patents

Abstract

826,331. Spray carburetting apparatus. GENERAL MOTORS CORPORATION. March 14, 1958 [March 15, 1957], No. 8250/58. Class 7(3) Apparatus for forming the combustible charge for an internal combustion engine comprises an air induction system and a fuel injection system, the air induction system having in parallel therein a pair of passages 14, 16 each with a venturi and a throttle and the fuel supply system having a fuel metering mechanism responsive to a venturi produced signal, the throttles being so arranged that when the throttles are moved from a closed to an open position, the throttle in one passage begins to open before the throttle in the second passage so that the venturi signal does not then fall below a certain value. As shown, when both throttles are closed the collar 36 engages the lip 32 so that when the smaller throttle 18 is initially opened the rod 30 slides axially through the lip 32 the throttle 20 therefore remaining closed until the collar 34 engages the lip 32. The lengths of the arms 26, 28 may be such that the rate of opening of the throttle 20 once begun is greater than that of the smaller throttle 18 so that both throttles reach the fully opened or closed position at the same time. The nozzles 44 may advantageously each have a reservoir (not shown) which can store the fuel until the associated cylinder intake valve opens. There is an enrichment device 111 which includes a diaphragm assembly 113. Under normal operating conditions the manifold vacuum in conduit 118 is sufficient to overcome the spring 124 and retain the rod 122 so that its end abuts against an adjustable bolt 128. Upon the sudden opening of the throttles the manifold vacuum in the conduit 118 is temporarily reduced to a point where the spring 124. moves the diaphragm 114 and rod 122 to the left thereby pivoting the link 82 anti-clockwise and moving the member 64 to the right to increase the quantity of fuel delivered to the nozzles 44. The arm 214 forms part of a cold starting enrichment device 200. As the engine warms up the thermo-responsive element 206 expands and thereby moves the pivot of the floating lever 210 to the left which results in more of the port 146 being covered and a leader charge being supplied to the engine. Since the manifold vacuum acts on the piston 218 against the force of the spring 230 the position of the piston depends on the resultant of these two forces. When the engine is running fast the fulcrum 180 will be further to the left for a certain engine temperature than when it is running slowly and the valve 48 will consequently be more closed and a leaner charge supplied to the engine. The casing 202 has a port 232 in communication with an air chamber around the exhaust manifold. Instead of two separate diaphragm assemblies 86 and 88 a single assembly can be used which includes a chamber comunicating at one side with the venturis and at the other side with the atmosphere. There are in the casing 54 ports 72, 74 through which fuel continuously flows on to the lands 66 and 68 so as to flush out impurities.