Development of a Luxury Vehicle Acoustic Package using SEA Full Vehicle Model

Interior noise has become a significant performance attribute in modern passenger vehicles and this is extremely important in the luxury market segment where a quiet interior is the price of entry. With the elimination of early prototype vehicles to reduce development costs, high frequency analytical SEA models are used to design the vehicle sound package to meet targets for interior noise quality. This function is important before representative NVH prototypes are available, and later to support parameter variation investigations that would be cost prohibitive in a hardware test. This paper presents the application of an analytical full vehicle SEA model for the development of the acoustic package of a cross over luxury utility vehicle. The development concerns addressed were airborne powertrain noise and road noise. Power flow analysis was used to identify the major noise paths to the interior of the vehicle. The SEA model allowed the performance of alternative designs to be assessed, the reduction of the power input from the major noise paths to be quantified and optimization of the acoustic package for both road noise and powertrain noise to be completed. The SEA model was used to drive acoustic package design to meet not only acoustic targets but also the mass and costs targets and deliver an optimized package.

The other major benefit of the full vehicle model that this paper will present are the impacts of not meeting sub-system requirements that are usually rolled down to the supplier. This is invaluable as it informs the vehicle design team what the impact is on the sound pressure level at the “drivers ear” of not meeting subsystem requirements, for example the “engine compartment absorption or front of dash transmission loss requirement”. It is concluded that the use of a detailed SEA model is a highly valuable design tool to support ‘A’ to ‘B’ design and material comparisons, to identify major noise paths, and to provide direction to the program.