ADAPTIVE ELECTRONIC CONTROL OF POWER-ON UPSHIFTING IN AN AUTOMATIC TRANSMISSION

An upshift control in which open-loop control parameters are adaptively adjusted to improve the shift quality in a subsequent upshift to the same ratio. A multi-variable adaptive control methodology attributes detected torque phase timing deviations to variability in the on-coming fill time and/or return spring pressure, and suitably corrects the parameter(s) so that in the next shift of the same type, the detected deviation will be reduced or eliminated. The torque phase timing deviations are detected by measuring specified intervals in relation to the achievement of predetermined input and output acceleration conditions, and comparing the measured intervals with reference intervals. The gradients of the deviations in relation to the respective control parameter are determined and stored in a look-up table, and subsequently used to determine adaptive correction values.