Sound Package Development for a Vehicle in Static Condition 2019-26-0174

Sound package material selection plays a vital role in maintaining passenger comfort by suppressing noise inside cabin. Sound package development in static condition minimizes the extrinsic variables which influence the measurements. The consideration of static condition favors simulation and its correlation with test data. Once correlation is achieved, simulation inputs are used for further optimization and improvements. Noise control can be done in three levels by working either on source, path or receiver. In automobiles, there are many sources of noise such as engine, tire and wind. This topic deals with quantification of various transfer paths between source and receiver location using Power Based Noise Reduction (PBNR) method. This methodology is used in both simulation and testing along with its overall scope for improvement. It is best to quantify path strength in terms of energy levels instead of mere amplitude due to its independency on external test conditions. In this paper, High frequency Statistical Energy Analysis (SEA) is used for front loading. PBNR was predicted between noise sources (engine, tires etc.) and receiver seating locations for frequency range of 200 - 6300 Hz. In addition, PBNR is measured using Dodecahedral Source (DDS) and PU probe and correlated with simulation values. The critical paths are identified based on PBNR data and design modifications are proposed to meet the target levels.

The development activity was traced from baseline vehicle to modified one and improvement in PBNR level by 2-5 dB throughout the high frequency (>200Hz) range was achieved in static condition and the similar improvement reflected in dynamic condition as well. In 3rd gear, Wide Open Throttle (WOT) driving condition, improvement of 15% in Articulation Index (AI) is observed.