| 摘要 |
<p>An upshift control device for an automatic transmission is provided in which the transmission is shifted up by releasing an oil pressure from a first engaging element that has been engaged while applying an oil pressure to a second engaging element that has been released. This upshift control device includes an accumulator back pressure control valve using a pressure corresponding to a detected engine load and a pressure applied to the second engaging element as operating signal pressures, for switching from a supply position for supplying a back pressure of the accumulator to a drain position for draining the accumulator when a difference between the two operating signal pressures becomes equal to a predetermined value, a timing valve for selectively supplying or not supplying the pressure applied to the second engaging element to the accumulator back pressure control valve, depending upon a signal received from a valve control actuator, and accumulator back pressure control means for generating to the valve control actuator a command to inhibit the timing valve from being switched to a position in which the pressure applied to the second engaging element is not supplied to the accumulator back pressure control valve, when the upshift command is generated and the detected engine load is approximately equal to its minimum value.</p> |
