In the recent past, interior noise quality has developed into a decisive aspect for the evaluation of overall vehicle quality. At most operating points, the dominating interior noise share is generated by the powertrain.
Interior noise simulation is a new tool for upgrading interior noise. Based on measurements of air- and structure-borne noise excitations caused by the powertrain, the interior noise shares are determined by applying the properties of the transfer paths. By superimposing the individual interior noise shares, the overall interior noise can be predicted.
Well before the engine is operated in the vehicle for the first time, annoying interior noise shares, their causes and their transfer paths can be identified by subjective and objective analysis. This enables the engineer to focus on vital optimization measures as to excitations occurring at the engine as well as to transfer paths in the vehicle.
This paper describes how interior noise simulation can be implemented to improve vehicle acoustics. Aside from the identification of excitations of the pre-optimized engine, procedures for the determination of well-shaped air- and structure-borne noise transfer functions are described.
The interior noise simulation results are compared with the real interior noise and serve as a base for the evaluation of acoustic weak points of the engine and transfer behavior of the vehicle. For noise shares which impair interior noise quality, the dominating transfer path and the extent to which excitation and/or transfer path contribute to the problem are identified. For a component optimization conducted at the powertrain test bench, the influences on interior noise are shown by means of simulation.
Finally, future development trends for simulation and calculation of interior noise are discussed.