基于EMD和HHT的内燃机瞬时转速信号分析

简述了经验模态分解(EMD)和Hilbert-Huang变换(HHT)的基本方法和原理,对4缸汽油机在转速2 500 r/min、扭矩83.6 N.m工况下的瞬时转速信号进行了EMD分解,将分解后的各个固有模态函数(IMF)分量作了HHT变换和FFT变换,得到了各IMF分量的瞬时频率和瞬时幅值随时间变化的关系,结合内燃机理论,分析各个分量产生的原因。研究结果表明,EMD算法能够有效地分离瞬时转速信号中的各个频段的信息,并且各IMF分量都有其物理意义。

Analysis of ICE Instantaneous Speed Signal Based on EMD and HHT

The basic method and principles of empirical mode decomposition(EMD) and Hilbert-Huang transform(HHT) were introduced.For a 4-cylinder gasoline engine,the instantaneous speed signal was decomposed under the 2 500 r/min and 83.6 N·m condition with empirical mode decomposition method.The intrinsic mode function(IMF) was transformed with Hilbert-Huang transform and fast Fourier transform,the instantaneous frequency and instantaneous amplitude relations with time were acquired and finally the IMFs were analyzed combining with internal combustion engine theory.The research result shows that EMD algorithm can identify different frequency information,which has its own physical significance,from the engine instantaneous speed signal.