Abstract: A system and method for controlling a powertrain including an automatic transmission include determining a value representing requested powertrain output, determining a rotational speed representing current operating conditions, generating a command to initiate a ratio change in the automatic transmission, and determining a dynamic pressure for the automatic transmission during the ratio change based on the requested powertrain output and the rotational speed. The requested powertrain output may be a wheel torque determined in part by accelerator pedal position. A performance adder based on requested wheel torque may be provided to further enhance operation.

Abstract: A system and method for controlling a vehicular powertrain including an internal combustion engine, an automatic transmission having a plurality of selectable gear ratios, and a controller in communication with the internal combustion engine, the transmission, and an accelerator pedal, include determining a driver requested wheel torque based on position of the accelerator pedal, and determining a vehicle speed ratio changing threshold based on the driver requested wheel torque. In one embodiment, the system and method determine a value indicative of current barometric pressure, determine a current gear ratio, and modify the driver requested wheel torque based on the current barometric pressure and the current gear ratio to determine a compensated wheel torque. The compensated wheel torque is used to determining the ratio changing threshold. Offset values are included to adjust for barometric pressure variation, transmission oil temperature, and to prevent gear hunting or excessive ratio changing.