Dynamic Characterization of a Twin Plate Torque Converter Clutch During Controlled Slip

This paper details testing for torque converter clutch (TCC) characterization during steady state and dynamic operation under controlled slip conditions on a dynamometer setup. The subject torque converter under test is a twin plate clutch with a dual stage turbine damper without a centrifugal pendulum absorber. An overview is provided of the dynamometer setup, hydraulic system and control techniques for regulating the apply pressure to the torque converter and clutch. To quantify the performance of the clutch in terms of control stability, pressure to torque relationship and the dynamic behavior during apply and release, a matrix of oil temperatures, output speeds, input torques, and clutch apply pressures were imposed upon the torque converter. The torque capacity of the clutch is estimated with the dimensions of the friction surfaces and pressure plate and an enhanced lookup data of K-factor obtained through testing of the hydrodynamics at input torques from 10 to 200 Nm over a speed ratio range consistent with controlled slip. The influence of controlled operating point parameters is reported as TCC apply pressure verse estimated TCC torque. The effect of temperature, output speed and the sign of input torque are shown to a departure from the normally assumed linear relationship between pressure and torque. The results and procedures presented can be utilized to improve in vehicle control schemes through more accurate pressure to torque gain scheduling.