| 摘要 |
PURPOSE:To display a compensating function against oil temperature change without using such a special sensor as an oil temperature sensor in a device to control hydraulic pressure by an electromagnetic valve provided on a hydraulic pressure control circuit of a hydraulic actuation type transmission for a vehicle. CONSTITUTION:From an actual electric current value 1a electrifying a solenoid of an electromagnetic valve and applied voltage Va, an actual resistance value Ra of the solenoid is computed (S7). Temperature of the electromagnetic valve is roughly equal to oil temperature, and the resistance value Ra specifically related with temperature becomes a parameter to estimate the oil temperature. Additionally, as the resistance value changes in accordance with self heating of the solenoid, the oil temperature is discriminated (S8) by adding cooling water temperature TW of an engine additionally, one corresponding to the oil temperature as a map to express a hydraulic pressure-electric current characteristic of the electromagnetic valve (S9), and in accordance with the selected map, electrification to the electromagnetic valve is controlled. |
