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The complex design and loading conditions of the wheel-hub assembly and decisive safety demands make it necessary to proof the wheel fasteners under reliable, service-like testing conditions. In this paper main parameters, the function and fatigue life of wheel fasteners and consequences for testing are described and discussed. The test procedure is based on the Biaxial Wheel Test Method, whereby the existing load program »Eurocycle« was extended by additional braking and torsional force sequences. The test requirement and some typical test results are presented.

In the automotive industry a strong trend towards electrification is determined. It offers the possibility of a more flexible actuation of the vehicle systems and can therefore reduce the fuel consumption and CO₂ emissions for modern vehicles. This is not only valid for typical drive train components, e.g., for hybrid or pure electric vehicles, but also for chassis components and auxiliaries like power-steering pump or air-conditioning compressor. However, a further electrification is limited by the 14V power net of conventional passenger cars. The high electric currents required by new/additional electrical components may lead to increased line losses and instability in the vehicle electrical system. With the introduction of a medium voltage level (≺60V) these problems can be circumvented.

The permanently increasing number of convenience and safety functions leads to higher complexity of in-car electronics and the rapidly growing amount of sensors, actuators and electronic control units places higher demands on high- speed data communication protocols. Safety-critical systems need deterministic protocols with fault-tolerant behavior. The need for on-board diagnosis calls for flexible use of bandwidth and an ever-increasing number of functions necessitates a flexible means of extending the system. None of the communication solutions available on the market until now (like CAN or TTP) have been able to fulfill all these demands. To solve these problems, BMW together with several semiconductor companies has developed a new protocol for safety-critical applications in automotive vehicles.