Abstract: A microcomputer determines that an abnormality has occurred in calculation functions regarding calculation of an injection amount command value and the like, based on a deviation of the injection amount command value, in an increasing manner, from a monitoring injection amount. The microcomputer calculates, based on a cooling fluid temperature of an engine, a start-up injection amount such that the start-up injection amount becomes smaller when the cooling fluid temperature is high than when the cooling fluid temperature is low, and uses the start-up injection amount as the injection amount command value immediately after the completion of start-up of the engine. Besides, the microcomputer uses the smaller one of a start-up injection amount calculated this time and a monitoring start-up injection amount calculated last time, as a monitoring start-up injection amount that is used as the aforementioned monitoring injection amount immediately after the completion of start-up of the engine.

Abstract: A microcomputer determines a presence of an abnormality of a fuel injection quantity control device based on a comparison between a required injection quantity as a command value for the amount of a fuel injected from an injector in one engine cycle and a total monitor injection quantity as a total value of monitor injection quantities obtained from an energization time monitor value of the injector for each fuel injection in the one engine cycle. The microcomputer removes a micro-injection correction amount from the monitor injection quantity when the monitor injection quantity is below a determination value and executes a removal processing in which the removal of the micro-injection correction amount from the monitor injection quantity is not performed when the monitor injection quantity is at least the determination value. The total value of the monitor injection quantities after the removal processing is regarded as the total monitor injection quantity.

Abstract: An engine control apparatus is equipped with a fuel injection amount computation unit, a determination process unit, and an engine abnormality process unit. The determination process unit determines, based on a deviation between a command injection amount and a monitoring injection amount, whether or not there is an abnormality in fuel injection control. An injection amount threshold, which is used to make a determination on an abnormality in fuel injection control, is set larger based on a vehicle speed-associated parameter when the vehicle speed-associated parameter is a value corresponding to a case where a vehicle speed is high than when the vehicle speed-associated parameter is a value corresponding to a case where the vehicle speed is low.

Abstract: A microcomputer determines that an abnormality has occurred in calculation functions regarding calculation of an injection amount command value and the like, based on a deviation of the injection amount command value, in an increasing manner, from a monitoring injection amount. The microcomputer calculates, based on a cooling fluid temperature of an engine, a start-up injection amount such that the start-up injection amount becomes smaller when the cooling fluid temperature is high than when the cooling fluid temperature is low, and uses the start-up injection amount as the injection amount command value immediately after the completion of start-up of the engine. Besides, the microcomputer uses the smaller one of a start-up injection amount calculated this time and a monitoring start-up injection amount calculated last time, as a monitoring start-up injection amount that is used as the aforementioned monitoring injection amount immediately after the completion of start-up of the engine.

Abstract: An engine control apparatus is equipped with a fuel injection amount computation unit, a determination process unit, and an engine abnormality process unit. The determination process unit determines, based on a deviation between a command injection amount and a monitoring injection amount, whether or not there is an abnormality in fuel injection control. An injection amount threshold, which is used to make a determination on an abnormality in fuel injection control, is set larger based on a vehicle speed-associated parameter when the vehicle speed-associated parameter is a value corresponding to a case where a vehicle speed is high than when the vehicle speed-associated parameter is a value corresponding to a case where the vehicle speed is low.

Abstract: A microcomputer determines a presence of an abnormality of a fuel injection quantity control device based on a comparison between a required injection quantity as a command value for the amount of a fuel injected from an injector in one engine cycle and a total monitor injection quantity as a total value of monitor injection quantities obtained from an energization time monitor value of the injector for each fuel injection in the one engine cycle. The microcomputer removes a micro-injection correction amount from the monitor injection quantity when the monitor injection quantity is below a determination value and executes a removal processing in which the removal of the micro-injection correction amount from the monitor injection quantity is not performed when the monitor injection quantity is at least the determination value. The total value of the monitor injection quantities after the removal processing is regarded as the total monitor injection quantity.