Fuel injector failure detection circuit

In a vehicle and associated fuel injector failure detection circuit, the vehicle 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 for transmitting a low voltage state signal output when the low side terminal of the fuel injector produces a fly-back voltage pulse;
• a logic circuit having a functional equivalent output of an AND gate;
• an edge triggerable latch having at least one input and an output, internal to the injector power disconnection means, the latch having the at least one input in communication with the one shot timer, the latch output in communication with the logic circuit, the latch output changing state twice at the end of the injector peak time duration given the occurrence of the fly-back voltage pulse;
• a fast transition circuit for speeding the de-energization of the fuel injector, the fast transition circuit in communication with the low side terminal of the fuel injector;
• means 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, the disconnection means in communication with the one shot timer and the voltage sense comparator;
• means for protecting the high side terminal of the fuel injector from a circuit anomaly, the high side protection means in communication with the injector disconnection means and the fuel injector;
• and
• means for protecting the low side terminal of the fuel injector from a circuit anomaly, the low side protection means in communication with the injector disconnection means, voltage sense comparator, and the fuel injector.

In a vehicle and associated fuel injector failure detection circuit, the vehicle having at least one combustion chamber, a battery, 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, and an Electronic Control Unit (ECU), the ECU including a microprocessor, memory capabilities, and at least one bus line, the fuel injector failure detection circuit comprising:

• a high voltage power supply for increasing a voltage output level of the vehicle battery, the high voltage power supply in communication with the vehicle battery and the fuel injector;
• a logic circuit having a functional equivalent output of an AND gate;
• a voltage sense comparator for transmitting a low voltage state signal output when the low side terminal of the fuel injector produces a fly-back voltage pulse;
• a first edge triggerable latch having at least one input and an output, the at least one input in communication with the voltage sense comparator and the logic circuit, the output in communication with the one shot timer, the latch output changing states given an active low at the at least one latch input;
• a second edge triggerable latch having at least one input and an output, the at least one input in communication with the fly-back pulse detector, the time-out detector, and the first edge triggerable latch, the latch output changing state twice at the end of the injector peak time duration given the occurrence of the fly-back voltage pulse;
• 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, the one shot timer in communication with the second edge triggerable latch;
• a high side driver for protecting the high side terminal of the fuel injector from a high voltage, the high side driver in communication with the injector disconnection means and the fuel injector;
• a low side driver for protecting the low side terminal of the fuel injector from a high voltage, the low side driver in communication with the low side terminal of the fuel injector, and the voltage sense comparator;
• and
• a fast transition circuit for speeding the de-energization of the fuel injector, the fast transition circuit in communication with the low side driver.