| 摘要 |
An object of the present invention is to estimate a viscosity of a fuel with high accuracy at all times, irrespective, for example, of fuel properties or conditions of deterioration with time. An internal combustion engine 10 includes a fuel pump 32 for supplying an injection valve with fuel in a tank 24. An ECU 40 detects a transition time t that begins when a drive signal is outputted to the fuel pump 32 and ends when the pump enters a steady operating state. At a start of the fuel pump 32, the higher the viscosity of the fuel, the longer the transition time t tends to be. The ECU 40 therefore detects the viscosity of the fuel based on a deviation &Dgr;t between the transition time t and a reference time t0. If, for example, a biofuel is used, therefore, the latest viscosity can be accurately detected at all times even with the viscosity of the fuel fluctuating depending on, for example, properties or a condition of deterioration with time of the fuel, and the detection result can be incorporated in, for example, correction of a fuel injection pressure. |
