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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.

Corrosion is one of the main issues causing noise, vibration and harshness (NVH) in the wheel-end brake system. This paper describes the development of a sacrificial shield, mounted between the hub bearing unit (HBU) flange and the brake rotor, in order to avoid the forming of corrosion. The zinc (Zn) coated layers on the sheet metal shield provide a chemical defensive mechanism as it takes steel's place in the corrosion reaction. Consequently RED rust will not start forming until all the Zn has been converted to WHITE rust. The duration of the conversion period is the “temporary corrosion protection period” for the HBU and rotor flanges and can maintain the delivered brake rotor Lateral Run Out (LRO) up to the first scheduled service for the rotor. If each time the Sacrificial Shield is replaced when brake rotor service takes place, the proper functioning and service life of the brake system will be prolonged.

Powerful vehicles that are adequately designed to corner at high speeds can generate very high lateral forces at tire-road interface. These forces are counter balanced by chassis, suspension and brake components allowing the vehicle to confidently maneuver around a corner. Although these components may not damage under such high cornering loads, elastic deflections can significantly alter a vehicles performance. One such phenomenon is increased brake pedal travel, to engage brakes, after severe cornering maneuvers. Authors of this paper have worked together to solve exactly this problem on a very powerful luxury segment car.