柴油机气缸盖振动的自回归谱分析与状态监测

通过监测柴油机气缸盖振动信号,分别采用自回归谱方法和Fourier谱方法作分析处理,对柴油机进行状态监测.研究气阀敲击及气缸内燃气激励引起的气缸盖振动特征,并给出适合于柴油机振动状态监测的判据.研究表明,利用气缸盖振动信号监测运行中气阀间隙的变化和各气缸内负荷的变化是有效和可行的;基于参数法的自回归谱分析比Fourier方法估计得到的谱线更光滑,频率定位更准确,更适合于柴油机的状态监测.

Autoregressive spectrum analysis of cylinder cover vibration and condition monitoring of diesel engine

An investigation on diesel engine condition monitoring is conducted by use of cylinder cover vibration signals. Both autoregressive spectrum analysis and Fourier spectrum method are adopted in order to analyse the vibration signals. The characteristics of cylinder cover vibration signals excited by valve impacts and combustion forces are discussed, and some criteria suitable for diesel engine vibration monitoring are proposed. The results show that it is effective and feasible to detect the variations in valve clearance and engine cylinder load from cylinder cover vibration signals. Furthermore, this investigation shows that autoregressive spectrum is smoother than Fourier spectrum, with more accurate frequency location, so it is more suitable for diesel engine condition monitoring.