USE OF DIRECTIONAL SPECTRA FOR DETECTION OF ENGINE CYLINDER POWER FAULT

A diagnostic method, which uses the two-sided directional power spectr a of complex-valued engine vibration signals, is presented and tested with four-cylinder compression and spark ignition engines for the diag nosis of cylinder power faults. As spectral estimators, the maximum li kelihood and FFT methods are compared, and the multi-layer neural netw ork is employed for pattern recognition. Experimental results show tha t the success rate for identifying the misfired cylinder is much highe r with the use of two-sided directional power spectra than conventiona l one-sided power spectra.