增压中冷管高频啸叫辐射噪声试验研究与改进

High-frequency Whistle Noise Investigation and Optimization of Turbocharged Air Duct System

涡轮增压发动机通常表现为高频噪声问题,尤其是内部高温高压高速气流流经局部结构时,易于产生气流再生噪声,表现为窄频带特性。本文主要针对整车试验过程中出现的车内高频"啸叫"问题进行研究与解决方案。首先,通过整车转毂试验分析判断噪声源及主要传递路径。其次,通过增压中冷管路消声器的结构优化改进,试制相应的样件方案。最后,优化后的增压管路安装于整车并在转毂消声室内验证车内噪声改善效果。结果表明,优化改进的增压中冷管消声器,对5500-6500Hz高频"啸叫"成分均有较明显的抑制效果,表明消声器外壳体与内部芯子的空腔径向尺寸与气流再生噪声的产生相关性较高,为增压管路的工程开发提供有效的设计指导。

High-frequency noise issue is much more serious on the turbocharger engine compared with natural aspirated engine.Especially when the air flow crushes the section-change area with high temperature,high pressure and high velocity,the air induced flow noise would happen,usually acts as narrow-band spectrum noise,and sometimes is called whistle noise.In this paper,we focused on the high-frequency whistle noise investigation and engineering solution.First,the vehicle test was preceded in the anechoic room with roller bench.As a result,the main noise source and transfer path was analyzed and the turbocharged air duct system is the main radiated path of such high-frequency whistle noise.Then,the interior structure of the silencer was modified and optimized,as well as completing prototype manufacturing.Finally,the prototypes were mounted on the vehicle and preceded the vehicle NVH test.In result,the modified silencers show great performance on 5500-6500 Hz frequency band noise,which indicates highly relevant to the cavity distance between the outer shell and inner element of a certain silencer.The high-frequency whistle noise disappeared and such investigation could help provide engineering guide for turbocharged air duct system development.