Verfahren zum Steuern der Gangwechsel in automatischen Getrieben.

摘要

In an automatic transmission 16, clutch-to-clutch powered downshifting is controlled by filling the on-coming clutch C1-C5 at a low pressure while ramping down the off-going clutch pressure Pioff until turbine speed is pulled up due to off-going clutch slippage, and then increasing the off-going pressure stepwise to compensate the change from static to dynamic coefficients of friction. Then the on-coming pressure Pion is gradually ramped up and a closed-loop profile control period starts wherein the slip of the on-coming clutch C1-C5 is measured and controlled to a slip profile by controlling the off-going clutch pressure Pioff. When synchronization of the on-coming clutch C1-C5 is first detected, a closed-loop sync control period starts wherein the off-going pressure Pioff is controlled to minimize the slip and the on-coming pressure Pion is ramped up at a steeper rate to begin clutch engagement during the sync control period.