某柴油机排气消声器低频噪声优化控制

Optimization control of low frequency exhaust noise of diesel engine muffler

为解决某柴油机排气低频噪声突出、主观感受差的问题,通过试验采集柴油机排气噪声频谱,分析不同频率下的噪声占比;在整机布置空间不变的情况下,修改消声器的各扩张腔、共振腔尺寸,优化设计排气消声器,并进行试验验证。结果表明:优化设计的消声器可以提高全频段消声能力,特别是低频消声能力,在低频段主要频率90、180 Hz附近的噪声降低12~16 dB,并可以兼顾不同温度下消声频率的变化,有效实现低频噪声的定量控制。该优化措施可以为降低柴油机排气低频噪声提供参考。

In order to solve the problem of the low frequency exhaust noise and achieve better subjective feeling of a diesel engine,the exhaust noise spectrum of the diesel engine is collected and the noise contribution is analyzed.The installing space is unchanged,this article focuses on the exhaust muffler optimized process and structure design by modifying the size of expand muffler and Helmholtz resonator and test verification.The results show that the muffler achieves higher transmission loss for all conditions especially at low frequency.The muffler is verified by testing,The noise near the main noise frequency(90,180 Hz) in the low frequency band is reduced by 12-16 dB.Meanwhile,the muffler show very good adaptability at different temperatures.The quantitative control of low frequency noise is effectively realized.The optimization and improvement can provide reference for reducing low frequency exhaust noise of diesel engine.