发明名称 |
Method of clutch-to-clutch closed throttle downshift in an automatic transmission |
摘要 |
In an automatic transmission, clutch-to-clutch closed throttle downshifting is controlled by filling the on-coming clutch at a maximum pressure command for a set period while commanding the off-going clutch pressure to a low value and exhausting the off-going clutch before the end of the fill period. At the end of the fill period the on-coming pressure is set to an initial value and then ramped up until turbine speed is pulled up due to off-going clutch slippage. Then a closed-loop profile control period starts wherein the slip of the on-coming clutch is measured and controlled to a slip profile. When synchronization of the on-coming clutch is detected, maximum pressure is commanded. If the throttle is opened during the downshift, the algorithm reverts to a powered downshift algorithm if the off-going clutch still has pressure or to an open-loop ramp control of the on-coming clutch if the off-going clutch has been exhausted.
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申请公布号 |
US5046174(A) |
申请公布日期 |
1991.09.03 |
申请号 |
US19900464054 |
申请日期 |
1990.01.11 |
申请人 |
GENERAL MOTORS CORPORATION |
发明人 |
LENTZ, CARL A.;HIBNER, JOHN A. |
分类号 |
F16H59/46;F16H61/00;F16H61/06;F16H61/08 |
主分类号 |
F16H59/46 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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