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以4120SG柴油机为研究对象,通过故障模拟试验测试了柴油机在气阀正常状态、气阀漏气状态下的缸盖声发射信号,对燃烧段声发射信号进行经验模态分解(Experience Mode Decomposition,EMD),计算了各个本征模分量(Intrinsic Mode Function,IMF)的能量分布及EMD能量熵。研究表明声发射信号能量主要集中在前3个IMF分量内,随着气阀漏气故障严重程度的增加,代表最高频IMF1分量能量相对增加,而能量熵H减少。通过自定义特征参数,提高了声发射应用于柴油机气阀漏气诊断方法的灵敏度。
Taking 4120SG diesel engine as the research object, the acoustic emission signals of the cylinder head under the normal state of the valve and the gas leakage of the valve were tested by the fault simulation test, and the empirical mode decomposition (EMD) of the AE signal of the combustion section ), The energy distribution and EMD entropy of each IMF (Intrinsic Mode Function, IMF) were calculated. The results show that the energy of acoustic emission signal is mainly concentrated in the first three IMF components. With the increase of severity of gas leakage, the energy of the IMF1 component of the highest frequency increases, while the energy entropy H decreases. By customizing the characteristic parameters, the sensitivity of acoustic emission diagnosis method applied to diesel valve leakage is improved.