GB1276614A - Fuel injection system - Google Patents

Abstract

1276614 Fuel injection systems BENDIX CORP 31 March 1970 [14 April 1969] 15082/70 Heading G1N [Also in Division H3] In an I.C. engine fuel injection control system pulses released in accordance with the engine crank angle are used to sequentially apply signals to AND gates 422 of respective injectors and to initiate pulses of the required injection duration from a device 26, which pulses are also applied to all the AND gates 422. The device 26 includes a generator which provides a signal having a time varying characteristic and a threshold detector which detects when the characteristic reaches a selected valve which is set in dependence upon engine operating parameter e.g. intake pressure, engine temperature &c. During the period the characteristic is below the selected value a pulse is applied to each of the AND gates. In one embodiment, Fig.4 (not shown), the generator comprises a ramp voltage generator (222) and the threshold detector (224) includes an emitter coupled transistor pair (248), (250), the base of one transistor having applied thereto the ramp voltage and the base of the other a voltage dependent on the engine parameters. A switching device is connected in the emitter circuit such that when the ramp voltage is below the engine parameter voltage an output is applied to the AND gates. In an alternative, Fig.5 (not shown), a capacitor which is connected to the gate electrode of a F.E.T. is charged, and the F.E.T. has applied to its base electrodes a voltage dependent upon engine parameters, such that the F.E.T. becomes conductive when the charge on the capacitor reaches a value sufficient to overcome the voltage. Any number of AND gates may be provided and each AND gate may be arranged to operate a group of injectors. Fluctuations in battery voltage which effect energization of the injectors automatically vary the time-varying characteristic of the generator.