混沌分形在内燃机振动信号分析中的应用

从理论上分析了柴油发动机燃烧过程的分形特性，运用混沌和分形理论对实际测得的发动机缸盖振动信号进行了分析，计算了信号的关联维数。结果表明：缸盖的燃爆冲击振动是一种混沌运动。而且，随着喷油器工作状态的不同，信号的关联维数也发生变化。系统振动不确定性成分增多，关联维数变大，系统振动确定性成分增多．关联维数变小。通过选择合适的嵌入维数，计算的关联维数能够反映系统的真实特性，关联维数可以作为发动机状态监测和故障诊断的一个特征参量。

Chaos and Fractal Application for Analyzing Vibration Signals of Diesel Engine

The fractal characteristics of combustion process of diesel engine are analyzed based on the theory of chaos and fractal application by analyzing the actual vibration signals of diesel engine cylinder head and calculating the correlation dimensions of the signals. Result indicates that combustion vibration of cylinder head is a kind of movement of chaos. With the work state change of oil ejector, the correlation dimensions of the signals are also changed. When the uncertainty of cylinder head vibration increases, the correlation dimensions have gone larger. When the certainty of cylinder head vibration increases, the correlation dimensions have gone lesser. By choosing suitable insertion dimensions, the correlation dimensions can reflect the real dynamic characteritics of the system and correlation dimensions could be used as a parameter to inspect and diagnose the state and the fault of diesel engine.