基于自适应阈值小波的发动机摩擦声发射信号降噪  

Noise Reduction of Engine Friction Acoustic Emission Signal Based on Adaptive Threshold Wavelet

作　　者：孙玉凤 介石磊 王明 SUN Yufeng;JIE Shilei;WANG Ming(College of Automotive Engineering,Yellow River Transportation University,Jiaozuo Henan 454950,China;School of Mechanical Engineering,Henan University of Science and Technology,Luoyang Henan 471003,China)

机构地区：[1]黄河交通学院汽车工程学院,河南焦作454950 [2]河南科技大学机械工程学院,河南洛阳471003

出　　处：《机械设计与研究》2024年第3期181-184,188,共5页Machine Design And Research

基　　金：河南省高等学校重点科研项目(18A460024)。

摘　　要：考虑到发动机存在复杂机构,受到外部信号的严重干扰,微弱活塞环-缸套信号极大增加了故障特征的提取难度,设计了一种基于自适应阈值小波的发动机摩擦声发射信号降噪方法。选择小波包算法获取声发射特征参数,以此判断活塞环-缸套系统润滑性能,构建得到了对润滑油品质进行声发射测试方法。研究结果表明:排气冲程未出现大幅变化的阀门开关干扰信号,40 kHz~60 kHz频带区间内的声发射RMS相对其余频带明显偏大,与转速呈正相关变化趋势。所有冲程对应声发射特征都与发动机转速呈现正相关变化规律。油膜表面会受到更大压力作用,从而引起油膜厚度的降低,形成更小的黏滞摩擦力。该研究为实现在线监测活塞环-缸套健康状态提供了可行思路,可以拓宽到其它的机械传动领域。Considering that the engine has complex mechanism and is severely interfered by external signals,the weak piston ring-cylinder liner signal increases the difficulty of fault feature extraction.A noise reduction method of engine friction acoustic emission signal based on adaptive threshold wavelet is designed.The acoustic emission characteristic parameters are obtained by the wavelet packet algorithm to judge the lubrication performance of the piston ring-cylinder liner system,and the acoustic emission test method for lubricating oil quality is constructed.The results show that the valve switch interference signal does not appear in the exhaust stroke,and the acoustic emission RMS in the 40 kHz~60 kHz frequency band is significantly larger than that in the other frequency bands,and is positively correlated with the speed.All the characteristics of stroke-response acoustic emission are positively correlated with engine speed.The surface of the oil film will be subjected to greater pressure,resulting in a reduction in the thickness of the oil film and the formation of less viscous friction.This study provides a feasible idea for on-line monitoring of piston ring and cylinder liner health status,which can be extended to other mechanical transmission fields.

关 键 词：声发射 小波包 活塞环-缸套 摩擦信号 自适应阈值 

分 类 号：TG156[金属学及工艺—热处理]