Application of Vehicle Interior Noise Simulation (VINS) for NVH Analysis of a Passenger Car

The overall perception of a vehicle's quality is significantly influenced by its interior noise characteristics. Therefore, it is important to strike a balance between “pleasant” and “dynamic” sound that fits the customer requirements with respect to vehicle brand and class [1]. Typically, a significant share of the interior vehicle noise is transferred through structure-borne paths. Hence, the powertrain mounting system plays an important role in designing the interior noise.

This paper describes an application of the method of vehicle interior noise simulation (VINS) to achieve a characteristic interior sound. This approach is based on separate measurements (or calculations) of excitations and transfer functions and subsequent calculation of the interior noise in the time domain. The VINS procedure allows for explicit separation (and listening) of the sound field into airborne and structure-borne shares and each share can be further decomposed into its constituent paths and directions.

In the vehicle model, which is the basis of the VINS method, the powertrain mounts are represented by frequency dependent transfer functions. In the application discussed in this paper, the influence of mount stiffness on the interior noise is calculated by virtually modifying the characteristics of these transfer functions. Critical noise paths are identified and analytically modified to achieve the desired interior noise characteristics. Finally, engine mounting system hardware changes are conducted and the measured data are compared to the VINS predictions.