Independent Suspension Drive Unit Spin Loss and Efficiency Testing
This recommended practice describes a spin loss and efficiency test procedure for Independent Drive Units (FDU & RDU) used in light-duty vehicles. The test procedure is conducted on an axle test rig. The test matrix determines the spin loss and efficiency values at three mileage conditions of the axle and utilizes an accelerated break-in procedure.
Rationale: This recommended practice provides a standardized test procedure to compare spin loss and efficiency values for Independent Drive Units among various designs and manufacturers. It utilizes established test conditions for vehicle fuel economy tests. The test regimen includes an accelerated break-in schedule to reduce the time of testing and to maintain consistency with regulatory requirements. Many Front Drive Units (FDU) utilize a Front Axle Disconnect (FAD) mechanism. This procedure can be used to compare the spin losses between the locked and unlocked operating conditions of the FAD.