Method for Engine Waveform Analysis and Fault Diagnosis Based on SFB and HHT

Abstract

Traditional engine waveform analysis in time-domain fails to perform an accurate fault diagnosis when the fault waveform is very close to the normal waveform in time domain. A novel engine waveform analysis method is presented. In this paper, the aim is to perform fault diagnosis efficiently under such circumstances. This method is proposed by combining a new technique, called sensitive frequency band (SFB) selection, with the developed Hilbert-Huang transform (HHT). This can alleviate "mode mixing" by removing noise from the engine waveforms and reveal the time-frequency characteristics for a signal by deriving its time-frequency spectrum (TFS) distribution. The method is then applied to analyze the engine injector-pulse-width waveforms, and it works well for signal noise reduction and fault diagnosis.