| abstract |
An engine fuel property estimation device capable of estimating the ignitability of fuel with higher accuracy is provided. In the fuel property estimation device according to the present invention, when the engine fuel is cut, an upper limit rotational speed NEmax is set based on the vehicle speed SPD, and the engine rotational speed NE becomes equal to or lower than the upper limit rotational speed NEmax (S102: YES), fuel injection for estimating the cetane number is performed, and the cetane number that is an index value of the ignitability of the fuel is estimated from the magnitude of the engine torque generated by the combustion of the injected fuel. Then, as the vehicle speed SPD is higher, the upper limit rotational speed NEmax is set to a smaller value, thereby suppressing variations in the ignition delay time and increasing the estimation accuracy of the cetane number. [Selection] Figure 4 |