GB1315327A - Internal combustion engine fuel supply control systems - Google Patents

Abstract

1315327 Fuel injection systems GENERAL MOTORS CORP 19 Nov 1970 [24 Nov 1969] 55054/70 Heading G1N In an I.C. engine fuel injection control system, injection pulses produced by a modulator circuit 72 in dependence upon intake pressure, fuel temperature, air temperature, engine temperature engine speed, engine acceleration, etc., are prevented from energizing the injection valve 42 when the throttle is in its closed position and the engine speed exceeds a reference value, hunting of the engine speed about this value, due to momentary increase of the engine speed above this value when the fuel is re-supplied when the engine speed falls below this value, being prevented. As shown, when the throttle is moved towards its closed position during deceleration, a switch 96 is closed to energize a trigger circuit 78 which includes a pair of transistors 80, 82 and a feedback resistor 84, an engine speed signal being applied at point 106. Closure of switch 96 renders transistor 80 conductive, but transistor 82 remains non-conductive, thereby rendering transistor 112 conductive to shunt the injection pulses to ground. However, when the engine speed falls below a reference value (just above idling), 80 is rendered non-conductive 82 is rendered conductive and 112 is rendered non- conductive thereby allowing fuel to be re-supplied. In this state, a feedback voltage exists across resistor 84, so that when the engine speed increases above the reference value as a result of re-application of fuel, this feedback voltage opposes the speed signal and the base-emitter bias voltage of transistor 80 is insufficient to turn on transistor 80.