Predictive Break-In and Rapid Efficiency Characterization of Beam Axles 2020-01-1413
This report is the result of a project by the USCAR Transmission Working Group Axle Subteam to rethink axle testing and develop a new beam axle break-in and efficiency characterization procedure with several goals in mind: Ensure the axle’s efficiency does not change as it is being characterized, build a detailed map of efficiency at a wide range of operating points, and minimize dyno time. The resulting break-in procedure uses an asymptotic regression approach to predict not only what the fully broken in efficiency of the axle is, but also how much the efficiency of the axle will change during the characterization phase. This allows the break-in cycle to terminate when the efficiency of the particular test article reaches a target stability, rather than after a predetermined duration, minimizing dyno time and ensuring that the completeness of the break-in is consistent across test pieces. The efficiency characterization procedure uses rapid probing of various torque and speed points as axle temperature rises to build a map of efficiency at a wide range of speed, load, and temperature conditions. By allowing temperature to float, the need for temperature stabilization between points is reduced, as is the number of cold soak events and total time on test. The procedure also includes exit criteria that sense and avoid test conditions that are damaging to a particular axle, improving repeatability of the characterization cycle. Finally, several temperature control methods and approaches to efficiency characterization are trialed, and the proposed break-in and efficiency characterization procedures are used to characterize several production axles.
William D. Guarino, Patrick R. Bias, Timothy Schumaier, Siqin Wei, Timothy Grzadzinski, Jasbir Singh, Thomas D'Anna, Joe Torres
Ford Motor Company, FEV North America, Inc., FCA US LLC, General Motors LLC