Comparison of Time and Frequency Domain Source Path Contribution Analysis for Engine Noise Using a Noise and Vibration Engine Simulator

In this paper a time-domain version of source-path-contribution analysis is investigated using a controllable source, an engine noise and vibration simulator installed into a trimmed vehicle, and compared to the results obtained using a more traditional frequency-domain source-path-contribution analysis. Both airborne and structure-borne inputs are investigated and the matrix method is used to calculate source contributions as sounds at a listeners' position inside the cabin. Operating data from a simulated run-up/run-down and sets of transfer functions (FRFs) are firstly used to estimate the strength of some defined point sources, acoustically and mechanically. Secondly the operating source strengths are combined with acoustic or vibro-acoustic FRFs to predict contributions at a receiver. In this work it is attempted to make the airborne and structure-borne models as simple as possible, and predicted contributions are validated against actual measured data.