Investigating Parameters Influencing Interior Noise of a Vehicle and Ways of Improving It 2011-01-1601

One of the most important factors that must be taken into account during vehicle design is the quality of noise and vibration produced by the vehicle. This is evident from manufacturer's attempt to produce quieter product. On the other hand, some of the vehicles have not good NVH properties and must be modified in order to be successful in the market. In this type of vehicles, no basic changes can be made, and focus must be on restricted improvements. In this research, a vehicle of this kind is selected and measures have been taken to improve its noise and vibration behavior. By implementing suspension techniques, some of the vibration characteristics of drive train and its influence on the interior noise at different engine speeds and under road load have been investigated. In addition, the effect of double layer instead of single layer muffler skin on the cabin noise has been probed. Also, the influence of vehicle intake chamber on interior and exterior noise level has been highlighted. After prioritizing these factors based on their effect on the interior sound pressure level, simplest and less costly improvements has been suggested and the amount of cabin noise improvement have been identified through step by step implementation of these changes.