Investigation of Transient Torque Converter Behavior, 03-9264

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Principal Investigators
Matt S. Castiglione
Brad P. Pohl 
Robert A. Smithson

Inclusive Dates: 07/01/01 – Current

Background - The physical phenomenon that governs how the three-element torque converter operates is dependent on very complicated fluid/blade interactions and fluid angular momentum considerations. CFD has accurately predicted the steady-state performance curves one would obtain if the candidate converter were tested in the laboratory in accordance with the Society of Automotive Engineers (SAE) Standard J 643. However, to date the transient simulation or characterization of a torque converter is not fully realized.

Approach - The current strategy is to develop a database of transient test data to be used along with basic physical relations to develop an empirical model that predicts the behavior of the torque converter in a transient condition. Using nondimensional variables, the transient test results will be compared to steady-state data to illustrate the differences. A model of torque converter transient behavior will be created. This transient model will be created such that it can be implemented into the WOTCAD and RAPTOR codes, which SwRI has developed for total vehicle simulation. 

Accomplishments - To date, two torque converters have been tested, and the initial results indicate that the transient performance is significantly altered from the static SAE test performance, as predicted. Increasing acceleration rates of the torque converter impeller are noted by increasing dynamometer drive voltages in the illustration below, with 9V approximating a wide open throttle launch.

Increasing acceleration rates of the torque converter impeller are noted 
by increasing dynamometer drive voltages

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