Stability test for slip operation of torque converter clutch

摘要

In an electronically controlled transmission adapted to control operation of a torque converter clutch in softlock and hardlock modes, a test to determine whether the clutch is operating with an acceptable slip magnitude in a control region or whether it is operating with a high level of slip or instability outside the control region. The test distinguishes periods of instability associated with deterioration of the clutch from transients associated with normal operating conditions and background noise. An instability counter, interval clock and warm-up cycle counter are used to determine an appropriate point for discounting prior events and reentering the control test. Continuous slip mode of operation of the clutch is disabled entirely after a predetermined number of verified unstable events have occurred.