Fuel injector failure detection circuit

Abstract

In a engine and associated fuel injector failure detection circuit, the engine having at least one combustion chamber, a battery, and at least one fuel injector having a high side and a low side terminal for introducing a fuel in the at least one combustion chamber, the fuel injector failure detection circuit comprising a one shot timer for transmitting a constant voltage state signal output when the fuel injector reaches a set current threshold at a start of an injector current peak time duration. A voltage sense comparator is provided for transmitting a low voltage state signal output when the low side terminal of the fuel injector produces a fly-back voltage pulse. A mechanism for monitoring current of the fuel injector during a rise time duration and the peak time duration ia also included. The circuit further provides a mechanism for disconnecting all electrical power supplied to the at least one fuel injector if the injector current fails to reach a peak level during the rise time duration or the fly-back voltage pulse fails to occur at the end of the peak time duration. Moreover, a mechanism for monitoring the fly-back voltage pulse produced by the low side terminal of the fuel injector is also included in the circuit.