| 摘要 |
PROBLEM TO BE SOLVED: To reduce speed changing shock at the time of downshifting in an automatic transmission. SOLUTION: As a downshifting command is outputted, a release side clutch in a speed change mechanism is released to make a roughly neutral state, so that input shaft rotation speed of the speed change mechanism is increased, while operating fluid charging control is conducted till a state just before an engagement side clutch in the speed change mechanism generates engagement force. The engagement force of the engagement side clutch is increased to complete downshifting to match timing when input shaft rotation speed rises to rotation speed equivalent to a target shift range of downshifting. In this downshifting control, whether operating fluid charging quantity to the engagement side clutch by charging control is proper or not is learned based on input shaft rotation speed rising characteristics or speed change ratio changing characteristics. Based on result of above learning, a control parameter (charging oil pressure or charging control time) for charging control in downshifting control to the applicable shift range for the next time is corrected. |
