| 摘要 |
PURPOSE:To prevent the generation of overshoot and speed change shock at the time of down-shift by confirming the completion of a stroke of a low speed step side frictional engagement element, and thereafter, releasing the engagement of a high speed step side frictional engagement element and engaging the low speed step side frictional engagement element. CONSTITUTION:A kick down servo 31 for driving a kick-down brake 30 is connected to a speed change control valve 37 through a 1-2 shift valve 33. A solenoid valve 67 for controlling the oil pressure is arranged in an oil passage 61 of the speed change control valve 37. Furthermore, a 4-3 shift valve 84 is connected to the kick-down servo 31 commonly with a front clutch 24. The solenoid valve 67 is controlled by an ECU 65 on the basis of the detection signals from various sensors 101, 103, 144. In this case, arrival of the accumulated value of the operating oil quantity supplied to the front clutch 24 at the discrimination value is confirmed. Thereafter, engagement of the kick-down brake 30 is released, and the front clutch 24 is engaged to finish the 4-3 speed change control. |
