Measurement Methods for Evaluating the Frequency Response Function of a Torque Converter Clutch

Abstract

In developing new torque converter clutch (TCC) technology, it is desirable to have accurate models to have confidence in performance predictions. To develop and calibrate TCC models, a test cell has been developed to measure the torsional vibration isolation performance of TCCs. The isolation performance is defined as the ratio of output torque to input torque, or torque transmissibility. This test cell uses an electric motor as a torsional exciter and a secondary motor (absorbing dyno) to control the output speed of the TCC. This loading condition, input torque-output speed, replicates the loading seen in a vehicle drivetrain where the engine provides a torque to the input of the torque converter and the vehicle’s wheels provide the speed boundary condition to the output. The torque transmissibility plot is acquired using a stepped sine approach with three frequencies per measurement. Two other excitation methods will be investigated to further reduce testing time.

• Step inputs (both up and down)

• Pseudo-random excitation (constant amplitude, random phase)

The torque transmissibility results of the new excitation methods will be compared to the previous measurement method for validation.

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