USCAR Traction Test Methodology for Traction-CVT Fluids 2002-01-2820
A traction test machine, developed for evaluation of traction-CVT fluids for the automotive consortium, USCAR, provides precision traction measurements to stresses up to 4 GPa. The high stress machine, WAMhs, provides an elliptical contact between AISI 52100 steel roller and disc specimens. Machine stiffness and positioning technology offer precision control of linear slip, sideslip and spin. A USCAR traction test methodology includes entrainment velocities from 2 to 10 m/sec and temperatures from -20°C to 140°C. The purpose of the USCAR machine and test methodology is to encourage traction fluid development and to establish a common testing approach for fluid qualification. The machine utilizes custom software, which provides flexibility to conduct comprehensive traction fluid evaluations. The traction characterization of three reference fluids covering a matrix of 90 test conditions shows the sensitivity of traction coefficient to stress, temperature, surface speed, spin and fluid type. The database with the three reference fluids provides a benchmark for future fluid development.