中文摘要：

内燃机活塞横向运动对缸套的撞击是机身振动信号最主要的激励源，其撞击情形完全反映在机身表面振动信号之中。通过对比分析装配普通缸套和表面凹坑处理的缸套两种工况下柴油机机身表面振动信号，研究规则凹坑缸套表面对柴油机振动的影响；采用小波包分解与重构的信号处理方法，获取高频信号分量并提取能量特征。研究发现，表面凹坑处理的缸套能够改善缸套－活塞组间的润滑性能，在油膜的阻尼下，活塞对缸套的横向撞击得到减轻；采取小波包分解与重构的信号处理方法，可以有效地提取信号某个频率段的信号特征。

英文摘要：

The impact of internal engine piston lateral motion to cylinder is the most important excitation of engine body vibration signals, and the impact status are totally reflected in the engine body surface vibration signals. By comparative analysis of the vibration signals of engine body assembled with common cylinder and concave-surface cylinder, the influence of concave-surface cylinder on diesel engine vibration was investigated. The method of wavelet packet decomposition and reconstruction was adopted to get high-frequency signal components and extract energy features. The results indicate that concave-surface cylinder can improve the lubrication performance of the cylinder-piston rubbing pair, and the lateral impact of piston-cylinder is alleviated with the damp of oil film. The use of wavelet packet decomposition and reconstruction can extract energy features effectively in a frequency band of signal.