某纯电动轿车低速轰鸣声排查及改进

Investigation and Improvement of Low-speed Booming of an Electric Vehicle

以某纯电动轿车为研究对象,运用频谱分析、阶次分析、模态分析方法,明确低速轰鸣声频率为78 Hz、声压级为38.6 dB(A)。测试分析结果表明轰鸣声与电驱阶次激励、电驱总成刚体模态和声腔模态耦合相关。考虑整车开发的周期及成本,改进电驱总成刚体模态,实现电驱总成刚体模态与车内声腔模态解耦,降低声腔模态激励频率振动幅值。客观测试78 Hz声压级由38.6 dB(A)降至28 dB(A),主观评价轰鸣声明显改善。

An electric vehicle was taken as the research object,and its low-speed booming frequency and sound pressure level were determined to be 78 Hz and 38.6 dB(A),respectively,by applying spec‐tral analysis,order analysis,and modal analysis methods.The test and analysis results show that the booming is related to the order excitation of the electric drive and the coupling between the rigid body mode of the electric drive assembly and the acoustic cavity mode.In view of the cycle and cost of devel‐oping a whole vehicle,the rigid body mode of the electric drive assembly was improved to decouple the rigid body mode of the electric drive assembly and the interior acoustic cavity mode,and the vibration amplitude of the excitation frequency of the acoustic cavity mode was reduced.In the objective test,the sound pressure level of 78 Hz was reduced from 38.6 dB(A)to 28 dB(A),and the subjective evaluation of the booming was significantly improved.