针对通过噪声的空滤器声学特性研究与改进

通过实验方法分析研究了一种中型乘用车通过噪声的特性,比较该车进、排气两侧通过噪声的声级和频谱特性,确定了进气噪声对车辆进气侧通过噪声的重要影响.为了解决该车进气噪声的问题从而达到整车降噪的目的,应用实验与边界元法计算两种手段,对该车空滤器的频率响应特性进行了研究.研究发现空滤器声系统的第一阶声固有频率与进气噪声基频相耦合是造成该车辆进气侧通过噪声高于排气侧的重要原因.基于这一研究结果,在计算和实验的基础上利用Helmholtz共振腔对空滤器的声学特性进行了改进,改进后的空滤器对降低车辆进气侧通过噪声有很好的作用.

Investigation and improvement of air-in filter acoustic performance towards pass-by noise

The characteristic of pass-by noise was studied through experiments. To compare the sound pressure level and frequency characteristic of acoustic signals sampled in the experiment, the induction noise was found to contribute greatfully to the pass-by noise of vehicle left side, where inlet of engine was mounted. In order to reduce the induction noise, an investigation was carried out towards the air-in filter acoustic performance based on experiments and boundary element calculation. The investigation revealed that the first order of the acoustic modes of air-in filter coincides with the foundation frequency of induction noise, and that the couple in frequency domain makes the sound pressure Of left side be higher than right side where exhaust system was settled. The optimization of the air-in filter acoustic performance by Helmholtz resonator based on calculation and experiment has effect on the decrease of pass-by noise.