Abstract: A fuel property determining device for an engine is provided, the device retarding a fuel injection timing and determining a fuel property based on a combustion variation of the engine caused by the retarding. The device includes a processor configured to control a parameter related to combustibility so as to degrade a combustion state before the fuel injection timing is retarded, the parameter being different from the fuel injection timing.

Abstract: A fuel property determining device for an engine is provided, which retards a fuel injection timing and determines a fuel property based on a combustion variation of the engine caused by the retarding. The device includes a first determining module for setting a retarding amount to a first setting amount at an early stage of the fuel property determination, and in a case where the variation is above a first given value when the first amount is set, suspending the retarding and determining that the fuel property is a first fuel property, and a second determining module for setting the retarding amount to a second setting amount in a case where the variation is below the first given value when the first amount is set, and determining the fuel property based on the variation caused when the second amount is set, the second amount being larger than the first amount.

Abstract: A fuel property determining device for an engine is provided, the device retarding a fuel injection timing and determining a fuel property based on a combustion variation of the engine caused by the retarding. The device includes a processor configured to control a parameter related to combustibility so as to degrade a combustion state before the fuel injection timing is retarded, the parameter being different from the fuel injection timing.