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Environmental sustainability is morphing Automotive technical development strategies and driving the evolution of vehicles with a speed and a strength hardly foreseeable a decade ago. The entire vehicle architecture is impacted, and energy efficiency becomes one of the most important parameters to reach goals, which are now not only market demands, but also based on regulatory standards with penalty consequences. Therefore, rolling drag from all bearings in multiple rotating parts of the vehicle needs to be reduced; wheel bearings are among the biggest in size regardless of the powertrain architecture (ICE, Hybrid, BEV) and have a significant impact. The design of wheel bearings is a complex balance between features influencing durability, robustness, vehicle dynamics, and, of course, energy efficiency.

This paper will outline the technical challenges experienced and the engineering methods used to overcome them during the endeavor to reduce wheel hub units mass and friction. Results achieved by the project team are significant and have meaningful contributions both to the unsprung mass, inertia and rolling resistance reduction. These features directly enable fuel consumption reduction and related CO2 emissions as well as positively influencing vehicle dynamics. Paper will handle two separate subjects of weight reduction and drag related power loss improvement and their combined effect at vehicle level. It will provide both simulated and test measured data as well as the validation of various features. In the very near future every milligram of CO2 reduction will count. To achieve significant improvements engineers have to think out of the box, develop breakthrough technologies and sometimes totally rewrite the rule book.

This paper outlines the technical challenges experienced and engineering methods used to overcome them during the endeavor to reduce wheel hub units mass and friction. Results achieved by the project team are significant and have meaningful contributions both to the unsprung mass, inertia and rolling resistance reduction. These features directly enable fuel consumption reduction and related CO2 emissions as well as positively influencing vehicle dynamics. The two part paper handles the subjects of weight reduction and drag related power loss improvement and their combined effect at vehicle level. It provides both simulated and test measured data as well as the validation of various features. This first part will focus on the friction reduction with only an introductory mention on the weight reduction effort. In the very near future every milligram of CO2 reduction will count.