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The noise level and sound quality performance of a passenger vehicle are strongly dependent on the fluid-structure behavior that is the interaction between the air inside the cabin with its sheet metal structures. With the challenges of global platform vehicles and an increased ethanol usage as an alternative fuel, new approaches of product development and refinements become necessary in order to up-to-date standards of vehicle NVH (noise, vibration and harshness). By using a CAE model combined with experimental data, it was possible to predict the main noise and vibration propagation paths inside the vehicle, where some proposals could be handled in advance and then validated on vehicle. Several solutions may be found to solve issues that usually are delimited by technology, cost-benefit ratio, production ability, package restrictions and/or durability.

NVH (Noise, Vibration and Harshness) is an important vehicle attribute and focus in every Product Development at OEM'S (Original Equipment Manufacturers). Pass-by Noise is one of these aspects in order to improve noise vehicle as a whole. As a result, this paper will show opportunities that Pass-by Noise test can get in a new development of Commercial Vehicles, presenting the methodology, NVH improvements, Quiet Truck and Frequency Analysis as well as Robustness of Noise Package Development. Moreover, the presentation will consider all the requirements and the advantages that Pass-by Noise can accomplish in a new Sound Package Development to meet a new Conama Resolution. The focus on this topic is to meet a new Governmental Regulation (CONAMA 272/2000) and consequently improve overall noise quality showing procedures that will accomplish targets of NVH. Conclusions will present the advantages of the proposed method regarding to timing and cost and real cases examples will be mentioned.