Abstract: The intake sound pressure leads to the vibration of the air filter shell, which produces radiation noise. The radiation noise can be suppressed by optimizing the structure of the air filter. During the test of a hybrid pickup truck, it is found that there is an obvious roaring inside the engine at 2 000 r/min. According to the investigation of the roaring, it is found that the air filter shell roaring noise of the intake system is the main contribution source. In order to solve this problem, the air filter modal analysis and intake sound pressure spectrum calculation are conducted at first, and the result shows that the excitation of the sound pressure of intake of air filter can resonate with the vibration frequency of the air filter upper panel, resulting in increased noise in the vehicle. Secondly, through the topology optimization of the upper shell of the air filter, the optimal location of stiffeners is found, which greatly improves the modal frequency of the upper shell of the air filter, avoids the frequency of the maximum value of the sound pressure excitation spectrum, and eliminates resonance. And then, through the calculation of radiated noise, it is confirmed that the total sound power level of the optimized upper shell of the air filter is reduced by 8 dB(A), and the noise improvement effect is very significant. Finally, through experimental vehicle verification, it has been proven that this research method can effectively solve this similar problem.

Key words: Hybrid pickup truck; Acoustics response; Intake air filter; Intake sound pressure; Morphology optimization; Radiation noise

摘要： 进气声压导致空滤壳体振动，从而产生辐射噪声，因此，可以通过优化空滤的结构来 抑制辐射噪声。一辆混动皮卡车在试验过程中发现，发动机在 2 000 r/min 时车内存在明显轰 鸣声。针对该轰鸣声进行排查，发现进气系统空滤壳体辐射噪声大是主要贡献源。为解决该 问题，首先进行空滤模态分析和进气声压谱计算，结果表明，进气系统声压激励与空滤壳体 面板的模态频率耦合共振，导致车辆噪声增加；其次，通过对空滤上壳体的拓扑优化，找出 了加强筋的最佳布置位置，使空滤上壳体模态频率得到大幅提高，避开了声压激励频谱最大 值的频率，消除共振；再次，通过辐射噪声的计算，确认了优化后的空滤上壳体的总声功率 级降低了 8 dB(A)，噪声改进效果非常明显；最后，通过实车验证，证明该研究方法可以有效 地解决此类似问题。

关键词: 混动皮卡；声学响应；进气空滤；进气声压；形貌优化；辐射噪声