GB1362460A - Fuel feed devices for internal combustion engines - Google Patents

Abstract

1362460 Fuel injection systems SOC INDUSTRIELLE DE BREVETS ET D'ETUDES 11 July 1972 [21 July 1971] 32384/72 Addition to 1266803 Heading G1N In an I.C. engine intermittent fuel injection system having an auxiliary throttle member 3 situated in the intake manifold 1 and a rotary member 10 providing a release signal A to initiate injection on each revolution, as described in the parent Specification, two sawtooth signals B, C are provided, B being triggered by the release signal A and C being triggered when the amplitude of the two signals become equal, one of the signals having a slope dependent upon the position of the auxiliary throttle member 3, is upon the flow of air to the engine, injection being provided for the duration t of the sawtooth signal B. The system consists of a bistable circuit 14 triggered by the release signal A, the output of circuit 14 being applied to trigger a first sawtooth generator 15 which provides the signal B having a slope determined by the position of the auxiliary throttle 3 (potentiometer 4). A second sawtooth generator 17 provides the signal C of constant slope (or varying with engine temperature). Both generators include a capacitor which is charged to provide the sawtooth signal. The outputs of the two generators are applied to a comparator 16 which provides an output to cause the capacitors to discharge when the amplitude of the sawtooth signals B and C become equal. The bistable circuit 14 is also reset by the comparator output so that the pulse output of the bistable circuit 14 is applied to energize the injection valves. Circuitry is provided to prevent injection when the engine is decelerating and the main throttle 2 is in its idling position. An AND gate 35 is provided, one input being connected to the output of the circuit 14 and the other to the output of a second comparator 19 via a switch which is closed to inhibit the AND gate when the throttle 2 is in its idling position. The comparator 19 compares the sawtooth signal C with a preset reference so that the AND gate is enabled when the engine speed falls to its idling value. Details of the circuitry of the above described system are given in Fig.2 (not shown).