Characterization of Structure-Borne Road/Tire Noise Inside a Passenger Car Cabin Using Path Based Analysis

摘要

Road/Tire noise is an important product quality criterion for passenger cars which are driving customers to decide upon the selection of a vehicle. Reduced engine noise and improvement in road conditions has resulted into more road/tire noise problem as average vehicle speed has gone up. Excitations from road surface travelling through the tire/suspension to vehicle body (structure-borne path) and air-pumping noise caused by tread patterns (air-borne paths) are the main contributor to tire noise issue inside the vehicle cabin. A lot of emphasis is put on the component level design as well as its compliance with vehicle structure to reduce the cabin noise. The objective of this work is to establish a methodology for evaluating structure-borne road/tire noise by evaluating the tire structural behavior and its interface with the vehicle body and its suspension system and identifying the contributing critical paths. NVH techniques like Modal Parameter Estimation and Transfer Path Analysis are used to characterize the contribution of noise from tires. The intent is to simplify and improve identification of the source path relationship and subsequent development of countermeasures for improvement of in-cabin noise. For an upcoming A-segment vehicle, a benchmark and other candidates tires are evaluated for their noise performance. For the problem tire, identification of the critical frequencies contributing to increase in-cabin noise levels was done. Transfer Path Analysis is carried out for identifying the path(s) which are responsible for higher in-cabin tire noise. After identifying the dominant path(s), counter-measure proposal(s) validation are carried out, which successfully reduce the overall structure-borne tire noise levels inside the cabin. By appropriate usage of this methodology, it was found to substantially reduce the tire noise contribution in the low frequency region and improved sound quality.