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 favours 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) simulation and testing and its scope for improvement. It is best to quantify path strength in terms of energy levels because this does not change with 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 cabin 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 identified based on PBNR data and design modifications proposed to meet the target levels.
Improvement in PBNR level by 2-5 dB throughout the high frequency(>200Hz) range is achieved in static condition and the similar improvement is reflected in dynamic condition as well. In 2nd gear, Wide Open Throttle(WOT) driving condition, improvement of 15% in Articulation Index (AI) is observed.