Multiple mode adaptive pressure control for an automatic transmission

Abstract

A transmission shift control having both multiple shift pressure moding and adaptive pressure schedule adjustment. A predetermined pressure schedule is used to develop an open-loop pressure command for the post-fill phase of the on-coming clutch in each upshift. Regardless which shift mode is selected, the controller measures the duration of the shift and compares the measured duration to an expected duration which will occur if the shift progresses as desired. The deviation, if any, is used to develop an adaptive correction amount, which is applied to shift mode dependent tables. In the base (Normal) mode, the pressure is determined in accordance with the pressure command from the predetermined pressure schedule, adjusted by an adaptive correction amount from a Normal mode correction table. In the Performance mode, the pressure command from the predetermined schedule is adjusted by adaptive correction amounts from both the Normal mode correction table and a Performance mode correction table. The Performance mode correction table is initialized at a minimum value which maintains at least a minimum pressure differentiation between the Normal and Performance modes so that a switch from the Normal mode to the Performance mode will always result in a firmer, sportier shift feel.