| 摘要 |
PROBLEM TO BE SOLVED: To solve a problem on shortage of filling of working oil for an engagement side clutch, while solving a problem of double engagement, in a down-shift control of an automatic transmission. SOLUTION: A hydraulic pressure control for the engagement side clutch is started after the lapse of a predetermined delay time td from the start of an hydraulic pressure control for a release side clutch, at a time of performing the down-shift control. The hydraulic pressure of the release side clutch has sufficiently been lowered before the hydraulic control of the engagement side clutch is started. Therefore, under the consideration of dispersion of actual hydraulic pressure with respect to a hydraulic pressure instruction value, even if stand-by hydraulic pressure Ph is set to be higher than that in the prior art so as not to occur the shortage of the filling of the working fluid, the double engagement is surely prevented. Further, by changing the delay time td of start of a filling control of the engagement side clutch depending on vehicle speeds, a period during which the stand-by hydraulic pressure Ph is kept to be an approximately fixed time is set regardless of the vehicle speeds. Therefore, stable down-shift control without influence of the vehicle speeds is implemented. COPYRIGHT: (C)2003,JPO |
