1／4波长管参数对发动机进气噪声的影响研究

1／4波长管是进气系统中的主要消音元件，在汽车NVH设计中得到广泛应用。在某车型开发过程中，发现在某频率下进气噪声较大。通过对整车的进气噪声测试，发现噪声主要是由于波长管参数不匹配引起。本文基于管道声学建立了波长管的数学模型，推导了传递损失函数，并采用MATLAB软件计算了不同参数下波长管的传递损失，确定了1/4波长管的结构参数。根据计算结果制作波长管并应用于某车型，利用Lms．Test．1ab软件测试了发动机的进气噪声，实验测试结果显示，安装新波长管后，汽车振动噪声有了显著改善，整车的NVH特性得到提高。

Effect of Parameters of 1/4 Wave Length Tube on Engine Intake Noise

The 1/4 wave length tube is the main silencer components for the engine intake system, which has been widely used in the NVH design of automobile. In the developing process of a vehicle, a greater roar has been found at a specific frequency. The vehicle experimental results show that, parameters of the 1/4 wave length tube are incorrect. Based on the duct acoustics principle, the mathematical model of the 1/4 wave length tube is established in this paper, and the transmission loss function of the 1/4 wave length tube is formulated. By using MATLAB, the transmission losses of wave length tubes are calculated with various parameters and its structural parameters are also determined. According to the results, 1/4 wave length tubes are made and applied in a vehicle. Then, the engine intake noise is measured with Lms.Test.lab. The experimental results show that, vibration noise has been significantly reduced with the installation of 1/4 wave length tubes, and the NVH characteristic of the vehicle is also improved.