To determine the minimum driving time of higher accuracy with minimum operation load in updating the minimum driving time of a fuel injection valve which is the time required until the start of fuel injection after applying a control signal to the electronically controlled fuel injection valve.

A sensor obtaining an output change corresponding to a fuel injection quantity by the fuel injection valve is used to acquire values S1, S2 equivalent to the fuel injection quantity when resetting two prescribed parameters P1, P2 for commanding different fuel injection quantities, in the direction of relieving the aging change degree of the fuel injection quantity. The acquired values S1, S2 are interpolated to determine an approximate expression K, and the time equivalent to the minimum driving time is newly computed based on an intersection between the determined approximate expression K and a value SO equivalent to the time of no fuel injection, to learn and update the previously held minimum driving time. This learning updating is carried out only when the degradation of the fuel injection valve is determined.

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