tools as a means for the monitoring and the diagnosis of assembly faults in internal combustion (i.c) engines through the cold test technology. Firstly, an approach based on the use of symmetrized dot patterns for the visual characterization of vibration signatures is proposed. This method is applied in order to obtain reliable thresholds for the pass/fail decision after the cold test. Secondly, the fault identification is discussed on the basis of the cyclostationary modeling of the signals. First of all, first-order cyclostationarity is exploited through the analysis of the Time Synchronous Average (TSA). Subsequently, second-order cyclostationarity is developed by means of the mean instantaneous power, Wigner-Ville Distribution (WVD) and Wigner-Ville Spectrum (WVS). Finally, the Continuous Wavelet Transform (CWT) is presented and compared with the Wigner Ville Distribution. In order to show the effectiveness and the limitations of the above-mentioned techniques, tests were carried out for a number of different faults. In this paper the results relative to a specific fault are shown as example.
On the monitoring and diagnosis of assembly faults in diesel engine cold tests: a case study
DELVECCHIO, Simone;D'ELIA, Gianluca;MUCCHI, Emiliano;DI GREGORIO, Raffaele
2009
Abstract
tools as a means for the monitoring and the diagnosis of assembly faults in internal combustion (i.c) engines through the cold test technology. Firstly, an approach based on the use of symmetrized dot patterns for the visual characterization of vibration signatures is proposed. This method is applied in order to obtain reliable thresholds for the pass/fail decision after the cold test. Secondly, the fault identification is discussed on the basis of the cyclostationary modeling of the signals. First of all, first-order cyclostationarity is exploited through the analysis of the Time Synchronous Average (TSA). Subsequently, second-order cyclostationarity is developed by means of the mean instantaneous power, Wigner-Ville Distribution (WVD) and Wigner-Ville Spectrum (WVS). Finally, the Continuous Wavelet Transform (CWT) is presented and compared with the Wigner Ville Distribution. In order to show the effectiveness and the limitations of the above-mentioned techniques, tests were carried out for a number of different faults. In this paper the results relative to a specific fault are shown as example.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
