基于声发射技术的内燃机润滑油粘度状态非介入式检测研究

润滑油的粘度变化是影响缸套-活塞环间摩擦润滑状态的主要因素之一。为了实现润滑油粘度的非介入式检测,本文通过声发射技术对缸套-活塞环间摩擦润滑状态进行了检测分析,采用小波变换、阈值降噪等方法实现信号的处理,得到了润滑油粘度与摩擦所产生声发射信号的近似关系。结果表明：随着转速的升高,声发射信号的电压幅值明显增加,缸内摩擦明显增大;随着润滑油温度的上升,粘度减小,声发射电压信号幅值逐渐减小,缸内摩擦相应地减小,且具有较好的线性相关性,为润滑油的状态检测与及时更换提供了技术手段,同时证明了声发射技术作为一种缸套-活塞环摩擦研究手段的有效性。

Research on Non - intervening Detection of Lubricating Oil Viscosity State of Internal Combustion Engine Based on Acoustic Emission Technology

The change of viscosity of lubricating oil is one of the main factors that affect the friction and lubrication state between cylinder liner and piston ring. In order to realize the non-invasive detection of the viscosity of the lubricating oil, the friction and lubrication state of the cylinder-piston ring is detected by acoustic emission technology. The signal processing is realized by wavelet transform and threshold noise reduction, Finally, the approximate relationship between the viscosity of the lubricating oil and the acoustic emission signal is obtained. The results show that the amplitude of the acoustic emission signal increases obviously with the increase of the rotational speed, it means friction increased significantly; With the increase of the temperature of the lubricating oil and the viscosity decreases, the amplitude of the acoustic emission voltage decreases gradually, the in-cylinder friction is reduced accordingly and has a good linear correlation, it provides a technical means for the detection and timely replacement of the lubricating oil. At the same time, it proves the effectiveness of acoustic emission technology as a method of friction between cylinder liner and piston ring.