Comparison of different techniques for time-frequency analysis of internal combustion engine vibration signals |
| |
| Authors: | Yang Jin Zhi-yong Hao and Xu Zheng |
| |
| Institution: | (1) Biosignetics Corporation, Toronto, Canada;(2) Biosignetics Corporation, 29 Downing Ct, Exeter, 03833 New Hampshire, USA;(3) Department of Cardiology, Izaak Walton Killam Children's Health Center, Dalhousie Medical School, Halifax, Nova Scotia, Canada |
| |
| Abstract: | In this study, we report an analysis of cylinder head vibration signals at a steady engine speed using short-time Fourier
transform (STFT). Three popular time-frequency analysis techniques, i.e., STFT, analytic wavelet transform (AWT) and S transform
(ST), have been examined. AWT and ST are often applied in engine signal analyses. In particular, an AWT expression in terms
of the quality factor Q and an analytical relationship between ST and AWT have been derived. The time-frequency resolution of a Gaussian function
windowed STFT was studied via numerical simulation. Based on the simulation, the empirical limits for the lowest distinguishable
frequency as well as the time and frequency resolutions were determined. These can provide insights for window width selection,
spectrogram interpretation and artifact identification. Gaussian function windowed STFTs were applied to some cylinder head
vibration signals. The spectrograms of the same signals from ST and AWT were also determined for comparison. The results indicate
that the uniform resolution feature of STFT is not necessarily a disadvantage for time-frequency analysis of vibration signals
when the engine is in stationary state because it can more accurately localize the frequency components excited by transient
excitations without much loss of time resolution. |
| |
| Keywords: | |
| 本文献已被 维普 SpringerLink 等数据库收录！ |
|
