GB1436012A - Synchronizing means for sequential fuel injection - Google Patents

Abstract

1436012 Electronic fuel injection systems for IC engines INTERNATIONAL HARVESTER CO 14 June 1973 [21 June 1972] 28298/73 Heading G3N In an electronic fuel injection system for an engine, means are responsive to sequencing signals supplied in synchronism to the intake strokes of the engine and to timing signals representing the desired duration of injection to cause the acuators of fuel injection valves to be energised in sequence, the sequencing signals being derived from a circuit which is supplied with triggering pulses from the engine ignition system in predetermined phase relation to each and every power stroke of the engine and a reset pulse from the ignition distributor in predetermined relation to the power stoke of a predetermined one of the engine cylinders. As shown, a sequence circuit 25 comprised of delay multi-vibrators 54, 56, a 2-bit counter 53, a de-coder 52 and AND gates 47-50, receives triggering pulses from the ignition coil 27 via multivibrator 54, and reset pulses from the ignition distributor 26 via multi-vibrator 56. A flip-flop 51 is set by each triggering pulse from multi-vibrator 54 and is reset after a variable time interval determined by a timer 31 which receives the analogue output signal of a computer 32 which receives signals dependent upon engine speed, intake air pressure, air temperature and coolant temperature, and is also connected to switches 33, 34 associated with the throttle. Acceleration and rate of change of intake air pressure may be taken into account. The output of flip-flop 51 is connected to an input of each AND gate 47-50, the other inputs of the AND gates being enabled in sequence determined by the counter 53 and de-coder 52 The outputs of the AND gates cause energization of the actuators of the injection valves V 1 -V 4 via driver circuits 41-44. In a practical embodiment, Fig. 3 (not shown), the function of the de-coder 52 and AND gates 47-50 is performed by three-input NOR gates, and the counter 53 is in the form of two flip-flops. Two inputs of each NOR gate are connected to the corresponding outputs of the two flip-flops, the third input of each NOR gate being connected to the output of flip-flop 51. Details of the multi-vibrators 54, 56, the flipflop 51 and the ignition circuit and distributor are described with references to Fig. 5 (not shown).