GB1283660A - Internal combustion engine fuel supply system - Google Patents

Abstract

1283660 Fuel injection systems GENERAL MOTORS CORP 20 May 1971 [10 June 1970 17 July 1970 (2)] 15988/71 Heading G1N In an I. C. engine fuel injection control system, additional fuel is supplied to the engine during starting, the extra fuel being applied only during an enrichment interval beginning when the starter is actuated and having a maximum duration directly related to the previous resting period (i.e. when starter is not actuated), to thereby prevent flooding. As shown, the system includes a multi-vibrator 92 triggered by pulses at 132 in synchronism with engine rotation to provide injection valve opening pulses. When a starting switch 150 is closed the starter 146 is energized to crank the engine, and an enrichment circuit 154 is energized to provide pulses at 166 which trigger the multi-vibrator 92. The frequency of these pulses is inversely related to the engine temperature (sensed by thermistor 172) and the battery supply voltage. Particularly, the frequency is doubled when the battery voltage falls below a pre-set level. The enrichment circuit, Fig. 2 or 6 (not shown), includes a timing circuit responsive to the actuation of switch 150 to produce a control voltage relative to a reference level to control an oscillator which provides the pulses at 166 depending on the relative values of the control voltage and reference level. The control voltage, Fig. 4 (not shown), is such that the enrichment interval has a minimum duration directly related to the duration of the present cranking period (i. e. duration that switch 150 is closed) and has a maximum duration directly related to the duration of the previous resting period and inversely related to the duration of the previous cranking period in excess of the previous enrichment interval. In an alternative, the pulses produced by the enrichment circuit may be used to energize an additional injector mounted in the intake manifold upstream of the main injector 48.