Estimation the Interior Sound Quality in BEV's Regarding Measurements on the Roller Test Bench: Focusing on Tonal Omponents

Development of BEVs gains more and more importance for OEMs, Tier 1s and DSPs and the project volumes continue to grow steadily. Even though the complexity of electric drive trains is reduced in comparison to combustion drive lines, the requirements for NVH development increases. Masking effects of noise through combustion noise fall away, the overall noise level decreases and the high frequency noises from the electric motors, inverters and transmissions dominate the overall impression of this new technology. Because of the missing combustion noise also noises like rolling noise from tires and wind noise is felt more and more disturbing for customers and pedestrians. The NVH character of any vehicle is highly dependent on its operating condition. With BEVs, it mainly depends on the vehicle speed, torque, temperature and state of charge of the battery. For this reason customers usually want to measure many speed-ups with constant torque steps. During a 3 Year cooperation with a big OEM almost all premium BEVs on the German market were measured/benchmarked to get a feedback about the own NVH performance. In addition, the desire for objective characteristic values arose. Based on the extensive published research on the topic of prominence of tones in electric vehicle interior noise this paper introduces an approach for the estimated sound quality from roller test bench measurements. An approach for the structure borne sound still needs to be developed and may be presented at a upcoming conference.