增压中冷管高频啸叫产生机理与解决方案研究

Investigation on Whistle Noise Mechanism and Solution of Turbocharged Air Duct System

涡轮增压发动机常常表现为高频噪声问题,在系统零部件配套时除需考虑增压器内部产生噪声的消声设计外,还需考虑气流再生噪声。本文主要针对整车试验过程中出现的车内高频“啸叫”的产生机理研究,并提出工程解决方案。研究基于前期排查诊断的传递路径分析,以工程量产为目标,探究该“啸叫”问题的工程化解决方案,并通过整车道路试验验证评估优化后消声器的实际声学性能。研究表明,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,二次气流噪声主要源于声腔与穿孔之间的湍流效应产生。改进后的消声器工程化方案对5500-6500Hz高频“啸叫”成分有显著的改善效果,提升了车内驾乘舒适性。

High-frequency noise issue is much more serious on the turbocharger engine compared with natural aspirated engine.So acoustic performance should be importantly focused during system developing,as well as the air induced flow noise design.In this paper,we focused on the high-frequency whistle noise investigation and engineering solution.Based on the pre-research on this topic,we were willing to find the engineering solution of this whistle noise and finally could be put in mass production.In result,the high frequency whistle noise was mainly caused by the so small cavity distance between the outer shell and inner element of a certain silencer,and turbulence effect was the core factor to this NVH issue.And the modified silencers show great performance on 5500-6500Hz frequency band noise.The high-frequency whistle noise disappeared and such investigation has helped improve the NVH level in the car.