Iqbal, S., Al-Bender, F., Pluymers, B., and Desmet, W., "Experimental Characterization of Drag Torque in Open Multi-Disks Wet Clutches," SAE Int. J. Fuels Lubr. 6(3):894-906, 2013, doi:10.4271/2013-01-9073.
The objective of the present study is to experimentally characterize the drag torque in open multi-disks wet clutches. For this purpose, two groups of experiments are performed using an advanced SAE#2 test setup. The experiments are designed under real conditions of variable automatic transmission fluid (ATF) flow rate and higher clutch speed range as experienced by wet clutches in real operation. The first test group examines the influence of parameters such as ATF flow rate, ATF temperature, and disks size whereas, the second test group investigates the effect of disks rotational conditions on the drag torque. By analyzing, the obtained experimental results, the relationship between the amount by which the parameters are varied and the corresponding change in the drag torque are established. In addition, a general qualitative behavior of the drag torque as function of clutch speed is proposed and the associated physical phenomena are explained.