Anti-flood circuit for use with an electronic fuel injection system

Claim 1

In a fuel management system for a fuel-injected internal combustion engine comprising engine cranking means providing a cranking signal while the engine is being cranked, at least one electromagnetically actuatable fuel injection valve means, engine synchronization timing generator means for generating a timing signal synchronizing the operation of the injector means with an event in an engine revolution, temperature sensor means providing a temperature dependent signal having a magnitude varying with engine temperature, pulse-width computing means providing a series of variable width injector-actuation pulses, and injector drive circuit means normally operative to actuate the fuel injection valve means for periods corresponding to the widths of the injector actuation pulses transmitted thereto, anti-flood means for reducing the flow of fuel to the engine during cranking characterized by (a) fuel content storage means operative to store a fuel signal representing the magnitude of the quantity of fuel supplied to the engine during cranking; (b) variation means adapted to be coupled to said fuel content storage means to vary said fuel signal at a predetermined rate; (c) first logic means coupled to said fuel content storage means, to said variation means, to the pulse width computing means and to the engine cranking means, said first logic means being operative to couple said variation means and said fuel content storage means during an injector actuation pulse generated in the presence of the cranking signal; (d) reference means providing a reference signal; (e) comparator means having a first input coupled to said fuel content storage means and a second input coupled to said reference means; said comparator means providing an incipient flood output signal when the magnitude of said fuel signal exceeds the magnitude of said reference signal; and (f) second logic means comprising first AND gate means having a first input coupled to the pulse width computing means, a second input coupled to the timing signal generating means, and an output coupled to the injector drive circuit means, second AND gate means having a first input coupled to said comparator means output, a second input coupled to the cranking means, and an output coupled to said second input of said first AND gate means, said second logic means being operative to control the injector drive circuit when said comparator means provides said incipient flood output signal in the presence of the cranking signal.