| 摘要 |
PURPOSE:To prevent the generation of speed change shock by setting an operation oil pressure supplying to a low speed side friction engagement means to a prescribed value in the switch of a speed change indication to a downshift. CONSTITUTION:An automatic transmission 2 is composed of a torque converter 4, a gear transmission 3, a hydraulic circuit 5 and a controller 40 and the like. When it is switched to the speed change indication of downshift during upshift enforcement, at first the operation oil pressure in a low speed side friction engagement means is set to a prescribed value and a play filling operation is carried out. When it is finished and the low speed side friction engagement means starts to engage actually, the revolution speed of an input shaft and the change rate of this revolution speed are increased. Therefore, when this change rate reaches a prescribed value, it is judged that the play filling operation is finished and the feedback control of the operation oil pressure in the low speed side friction engagement means starts. Accordingly, the low speed side friction engagement means can be engaged by a proper operation oil pressure and the speed change shock can be reduced. |
