A Simplified Approach to Modeling Thermal Effects in Wet Clutch Engagement: Analytical and Experimental Comparison

The simplified isothermal model for wet clutch engagement previously developed by Berger, Sadeghi, and Krousgrill (Berger, E. J., Sadeghi, F., and Krousgrill, C. M., 1996, “Analytical and Numerical Modeling of Engagement of Rough, Permeable, Grooved Wet Clutches,” ASME J. Tribol., 119, p. 143) was extended to include fluid thermal effects. The modified Reynolds and thermal diffusion equations were simultaneously solved to obtain torque and temperature characteristics during wet clutch engagement. The modified Reynolds equation was integrated using the Adams-Gear scheme and the alternating direction implicit method (ADI) finite difference technique was used to solve the thermal diffusion equation. The model was used to study the effects of speed, temperature, and load on the torque transfer and lubricant temperature variation during wet clutch engagement. A comparison of thermal and isothermal results indicates that the thermal model generally predicts a longer engagement time and smaller peak torque than the isothermal model. Comparison of analytical and experimental results indicates that including fluid thermal effects in the model is critical for achieving good correlation between analytical and experimental results. [S0742-4787(00)01501-0]