Patent ID: 7089102
Filing Date: 2006-08-08
Classification: B60W,F16H,Y02T,Y10T

Abstract:
1. A method for controlling a powertrain that includes an engine, automatic transmission having an offgoing friction element to be disengaged during a gear ratio change, and a torque converter having a turbine, the method comprising the steps of: initiating a gear ratio change from a current gear ratio to a next gear ratio; determining a value representing a desired engine speed until disengagement of the offgoing friction element is detected; determining a predicted current gear synchronous speed, and an offset to the current gear synchronous speed; setting the desired engine speed equal to the predicted current gear synchronous speed plus an offset to the current gear synchronous speed; using the desired engine speed value to control engine speed until disengagement of the offgoing friction element is detected during the gear ratio change; determining a rate of increase of desired engine speed during a period following detection of the disengagement of the offgoing friction element; increasing the desired engine speed value at the start of the period by said determined rate of increase of desired engine speed during the period; and using the desired engine speed value to control engine speed during the gear ratio change.