Automatic transmission shift control based on clutch torque capacity detection using calculated transmission input torque

Abstract

A system and method for controlling a vehicle powertrain having a transmission to improve shift quality is based on detection of an initial rise time of an on-coming clutch torque capacity, which indicates the start of the torque phase. The initial rise time is detected using a transmission input shaft torque computation. The system may include a vehicle powertrain having an engine, a transmission coupled to the engine via a torque converter and a controller configured to initiate torque phase control when a difference between a first transmission input shaft torque and a second transmission input shaft torque exceeds a first predetermined threshold parameter during a shift event characterized by a preparatory phase, a torque phase and an inertia phase.

Dependencies are inferred from the claim text.