A Case Study on Road Noise Source Identification and Reduction Measures in a Compact SUV 2017-01-1863
Road noise and speech intelligibility are becoming ever more important, irrespective of the vehicle size, due to vehicle refinement as well as connectivity with mobile communication equipment. With better aerodynamic designs, development of refined powertrains, and a tectonic shift from I.C. engine to electric motors, road noise and wind noise will become more apparent to the customer and hence will become a priority for automakers to refine their vehicles. This paper describes the efforts undertaken to identify the road noise paths and develop countermeasures for a compact SUV vehicle. A hybrid test/CAE approach was followed to improve road noise performance of this vehicle. This effort involved developing tire CAE models from physical hardware and creating synthesized road-load input from data taken on roads. Significant efforts were made to ensure model quality; focus on performing component level tests like bushing /damper characterization at high frequencies, modal correlation, IPI, NTF, and measurement of noise levels due to road input. Using TPA, panel radiation/contribution, optimization techniques, structural as well as acoustic package changes were identified, to improve noise levels. Results of these methods were used to develop prototype components to modify the vehicle. Final on-road assessment resulted in a significant improvement in sound pressure level/speech intelligibility objectively as well as subjectively.