Method of controlling gear change in an automatic transmission

In an automatic transmission 16, upshifting is controlled by ramping down the pressure in an off-going clutch C1-C5 associated with a high speed ratio and increasing the pressure in an on-coming clutch C1-C5 associated with a lower speed ratio. The on-coming clutch C1-C5 has commanded pressure at a...

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Bibliographische Detailangaben
Hauptverfasser: HIBNER, JOHN ANTHONY, LENTZ, CARL ALBERT
Format: Patent
Sprache:eng ; fre ; ger
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Zusammenfassung:In an automatic transmission 16, upshifting is controlled by ramping down the pressure in an off-going clutch C1-C5 associated with a high speed ratio and increasing the pressure in an on-coming clutch C1-C5 associated with a lower speed ratio. The on-coming clutch C1-C5 has commanded pressure at a maximum value for an initial fill time, a lower increasing ramp value during the ramp of the off-going clutch until the on-coming clutch starts to engage, and then a closed-loop control until the clutch C1-C5 reaches a synchronous speed. The closed-loop control parameter is on-coming clutch slip speed which is controlled to a calculated slip speed profile. The profile has a first steep slope and a final less steep slope so that the actual slip can smoothly go to zero in a given time period.