Research on knocking factor calculating method based on empirical mode decomposition algorithm for kerosene engine

To realize the objective taking knocking factors as the criterion to determine knocking intensity for electron-controlled two-stroke kerosene engine, a algorithm of knocking factors based on empirical mode decomposition was proposed. In this method, engine cylinder combustion pressure signals were adaptively decomposed into certain Intrinsic Mode Function components and residual function. The high frequency knocking signal components were obtained by analyzing the intrinsic mode function components by fast fourier transformation. The crank angle corresponding to the residual function peak was chosen as the starting point of the knocking window and the ending point of the reference window. To obtain the knocking factors, absolute value of the high frequency signal components was integrated and the integral energy ratio of high frequency signal components was calculated within the knocking window and reference window. By abundant experimental verification, results show that the algorithm of knocking factors based on empirical mode decomposition for the electron-controlled two-stroke kerosene engine is practical and effective. It also solves the subjectivity problem of selecting the key parameters in designing low-pass and band-pass filters of Siemens VDO algorithm.