Monitoring device for fuel injection amount control apparatus

A monitoring device for a fuel injection amount control apparatus, the fuel injection amount control apparatus being configured to drive an injector provided in an engine based on an injection amount command value, the monitoring device comprising:

• a calculation unit configured to:
• in calculating the injection amount command value at intervals of a specified time,
• (i) calculate a start-up injection amount based on a cooling fluid temperature of the engine such that the start-up injection amount becomes smaller when the cooling fluid temperature is high than when the cooling fluid temperature is low,
• (ii) use the start-up injection amount as the injection amount command value from start of start-up of the engine to completion of start-up of the engine, and
• (iii) use the larger one of the start-up injection amount and a basic injection amount that is calculated based on an operation state of the engine, as the injection amount command value, after completion of start-up of the engine;
• and
• a determination unit configured to:
• in calculating a monitoring injection amount at intervals of a specified time,
• (i) use the larger one of a monitoring start-up injection amount calculated based on the start-up injection amount and a monitoring basic injection amount calculated based on the operation state of the engine, as the monitoring injection amount,
• (ii) use a start-up injection amount calculated this time by the calculation unit, as the monitoring start-up injection amount, from start of start-up of the engine to completion of start-up of the engine,
• (iii) use the smaller one of the start-up injection amount calculated this time by the calculation unit and a last monitoring start-up injection amount calculated by the determination unit, as a current monitoring start-up injection amount, after completion of start-up of the engine, and
• (iv) determine that the calculation unit is abnormal when an injection amount command value calculated this time by the calculation unit deviates, in an increasing manner, from a monitoring injection amount calculated this time.