The new challenges of NVH packages for BEVs 2019-01-1452
Battery electric vehicles (BEVs) bring new challenge when it comes to develop their NVH package, which is affected by many new factors. The noise sources from the powertrain are different, for instance due to the presence of tonal components, strong harmonics and potential whining noise. Another important aspect is the missing effect of masking noise from a combustion engine. As a consequence, other noise sources, such as tires, become more predominant. This means that the NVH package has to be re-engineered considering the new noise sources ranking and cannot just be significantly decontented in general. In addition, the NVH package should at least partly counterbalance the vehicle weight increase due to the presence of a large and heavy battery pack in order to maximize the driving range. In the early days of BEVs, OEMs mostly carried over technologies used on combustion engine vehicles to electric cars. With the development growth of specific vehicle platforms for electric cars, NVH strategies and technologies might strongly change. First, this paper aims at providing a benchmarking review of current BEVs. This covers an analysis of the NVH package and an NVH performance comparison of different BEVs based upon transfer function and road measurements. In addition, a comparison with subjective acoustic testing is done and the problematic of structure-borne noise relevance versus air-borne for battery electric vehicles is addressed. On the basis of this study, it is attempted to define future directions for the different components of the exterior and interior NVH package, the impact of the battery pack on the insulation requirements of interior trim parts is addressed, and the effect of lightweight underbody treatments with maximum acoustic effect is demonstrated. In the end, the potential benefit of e-powertrain encapsulation is also explained.
Grégoire Lepoittevin, Jan Horak, Davide Caprioli
Autoneum Holding AG
Noise and Vibration Conference & Exhibition