Interpreting sound emission of diesel engine separating combustion and mechanical noise sources
Résumé
The recent works in noise source separation methods based on coherence referencing like Cyclic Wiener filtering, have improved the interpretation of raw acoustic and vibration measurements on diesel engine. With Cyclic Wiener filtering, one of the main interest is to separate in the raw signal the component correlated to combustion noise from the mechanical noise. This method can also be combined in preprocessing with noise sources localization algorithms to enhance the results interpretation. The independent display of noise source localization map for each component links an external noise source located on a component to a combustion or mechanical origin. Some measurements have been carried with a diesel engine and the dedicated instrumentation, i.e. the pressures of 4 cylinders and the pulsed tachymeter for cyclic Wiener filtering and a microphone array for noise source localization. The processing has been carried out for several running condition. The analysis of the specific condition in increasing load illustrates the adding value of combining both methods.