ADAPTIVE CONTROL OF AN AUTOMATIC TRANSMISSION

摘要

In an automatic transmission 16 upshifting is controlled by ramping down the pressure in an off-going clutch C1-CS associated with a high speed ratio and increasing the pressure in an on-coming clutch C1-CS associated with a lower speed ratio. The on-coming clutch C1-CS 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 reaches a synchronous speed. The closed-loop control parameter is on-coming clutch slip which is controlled to a calculated slip speed profile. Parameters for controlling the quality of a shift such as on-coming clutch initial pressure, off-going clutch initial pressure and on-coming clutch fill time are automatically adjustable during vehicle use to correct shift aberrations which degrade shift quality. A fast adjustment mode is in effect initially to calibrate the transmission control for the engine and vehicle. After a smooth shift is obtained only small adjustments are allowed.