Identification of Valve noise source in an Engine based Higher order time frequency

초록

The two stage Adaptive Line Enhancer [1] and the sliced Wigner fourth order moment spectra (SWFOMS)[2] have been applied to detect the weak impulsive signals in mechanical systems, such as those caused by early faults. The SWFOMS, in particular, has been inherently more robust in detecting impulsive signals embedded in the presence of random (Gaussian) noise. However, the SWFOMS suffers from non-oscillating cross-terms for multicomponent signals. These cross-terms cannot be smoothed by a conventional kernel function such as an exponential kernel function, which has been used for smoothing of cross-terms in the bilinear time-frequency method [3]. In this paper, in order to smooth the non-oscillating cross-terms, the SWFOMS smoothed by the g-method has been developed and applied to the diagnosis of valve system faults in an automotive engine.