Patent ID: 6052640
Filing Date: 2000-04-18
Classification: B60W

Abstract:
A method for estimating a difference in a rate of rotation of a driving member and a driven member of a torque converter of an automotive powertrain, the driving member coupled to an engine output shaft and the driven member coupled to a transmission input shaft, comprising the steps of:estimating torque delivered to the driving member from the engine output shaft;estimating the rate of rotation of the engine output shaft;retrieving a stored slip correction value;estimating the difference in the rate of rotation as a function of the slip correction value and of the rate of rotation divided by the square root of the estimated torque;generating a transmission gear ratio as a function of the estimated difference;measuring actual transmission gear ratio while a transmission gear change is not in process;calculating a gear ratio error as a function of a difference between the generated transmission gear ratio and the actual transmission gear ratio;updating the slip correction value in direction to drive the gear ratio error toward zero.