| 摘要 |
PURPOSE:To provide surely travel without shortage of a driving force and occurrence of slippage by changing vehicle speed in the atmospheric temperature lower than a predetermined value into a speed change stage in which a difference of change gear ratio between the speed change stage and the existing speed change stage is smaller than that of the speed change stage determined on the basis of an engine load and vehicle speed. CONSTITUTION:An electronic control unit E calculates a speed change stage to be set on the basis of the input data of vehicle speed, throttle opening, shift position signal, cooling water temperature, atmospheric temperature and the like to output signals to a hydraulic controller C. Then the atmospheric temperature is measured to be lower than a predetermined value, the speed change stage is changed to another one having a changing amount smaller than that of the speed change stage determined by at least two factors of throttle opening and vehicle. Namely, since a road surface has a high possibility of freezing in a low atmospheric temperature, the speed change in such a case is achieved with small variation of torque, resulting in the difficulty of slippage of a tire and the performance of stable travel. |
