| 摘要 |
PURPOSE:To improve speed change responsiveness by suddenly lowering the back pressure of an accumulator in an oil path put in the release condition at the time of down-shift on judging that it is down-shift and a driver demands sudden acceleration. CONSTITUTION:A hydraulic control device of an automatic transmission gear includes a duty ratio valve for reducing line pressure depending upon ON-OFF time ratio of a solenoid valve S4 controlled by ECU, a pressure regulating valve 400, an accumulator 500 disposed in an oil path between a shift valve and a brake B2 for controlling transient characteristic of oil pressure to the brake B2 and an accumulator 600 disposed in an oil path to a clutch C2. In this case, when down-shift is detected and sudden acceleration is demanded, that is, a throttle opening is more than a set value, the solenoid valve S4 is turned on. Thus, after the back pressure PA of the accumulator 500 is suddenly lowered, and the oil pressure of the brake B2 is suddenly lowered, a speed change command is output. |
