SAE J3249_202607

This recommended practice describes the procedure to measure and report the operating efficiency for all types of constant velocity joints (including fixed and plunging/end motion type joints) used in cars, SUVs, and trucks. This includes halfshaft as well as propshaft applications. This does not apply to non-CV joints. Rotational inertia is not considered within the scope of this recommended practice. This recommended practice provides a common method to quantify and report the operating efficiency characteristics of a CVJ. This practice does not apply to parasitic losses (spin loss, churning loss, or zero torque loss) as experienced on deactivated AWD/4WD systems. The losses in this condition are significantly less and require higher accuracy than what is required in this recommended practice. Vehicle manufacturers are focusing on improving efficiency of components to reduce energy consumption. Constant velocity joints (CVJs) are used in many vehicle applications to transmit power from the power source to the wheels. Like other driveline components, CVJs have losses due to operating efficiency as well as parasitic loss (grease churning, seal deformation, etc.). This recommended practice proposes a procedure to measure and report CVJ efficiency.