| 摘要 |
A speed change control system for use in an automatic transmission includes a one-way clutch to be locked and to retain a rotary element in a speed change mechanism for establishing a predetermined gear stage and an engine braking frictional engagement element arrayed in parallel with the one-way clutch and adapted to retain the rotary element, thereby establishing the desired gear stage. The speed change control system further includes a throttle opening detector for detecting the stroke of depression of the accelerator pedal of a vehicle, a downshift detector for detecting a shift to a desired gear stage and an apply pressure controller for controlling the apply pressure of the engine braking frictional engagement element. A speed change decision is made to determine whether a speed change is ended for a predetermined time period, if the throttle opening is in a predetermined region and if the detected shift is a downshift to the desired gear stage. A pressure regulator holds the apply pressure of the engine braking frictional engagement element at a low level immediately before the application of engine braking pressure for a predetermined time period, and switches the apply pressure to a higher steady level, at which the application is kept, if the speed change ending decision is made. On the other hand, the pressure regulator raises the apply pressure gradually if the speed change decision is not made. |
