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Before a physical proto-vehicle is assembled, various components or subsystems are ready by Tier-I or II suppliers. During final design judgement of the vehicle thru’ CAE or Mule-vehicle testing, performance target compliance need be assured for all these components to meet the Vehicle-level NVH targets. The work here studies some of the major components of a passenger car. Their individual NVH response can be critical to be cascaded for meeting the final targets for the vehicles running over roads. Conclusions of the study challenge some of traditional beliefs or generic targets. Often the component level response deviating from its own targets may not have an adverse influence on NVH of the vehicle facing multiple excitations from tyre/road, wind and power-train in a frequency band of interest.

In-door simulation of Pass By Noise [PBN] Testing of a car was successfully attempted on a chassis dynamometer in a full-scale Vehicle Semi-Anechoic Chamber [VSAC]. The work has a practical approach for quick testing of vehicles to be submitted for certification. It has 3 parts: 1 Confirmation of overall Indoor PBN Testing as per ISO 362-1:2007 (E) 2 Correlation of the PBN-results obtained on the Track with those in the VSAC as per both Method A and [proposed] Method B based on vehicle-acceleration depending on Power to Mass Ratio of the Test-vehicle 3 Use of this In-door simulation for quick evaluation of design modifications of the vehicle to meet its PBN Limit with a safe margin Optimum no. of microphones was sought out in VSAC to reduce the set-up time without sacrificing accuracy of the results. Dyno-roller / tyre radiated noise need be reduced to have the close correlation with the Track results.

Vehicle refinement from point of view reduction in its Noise, Vibrations and Harshness (NVH) affects customer’s buying decision and it also directly influences his/her driving experience on road at different speeds. Customer voice, however, indicates that a traditional process of developing design solutions is not aligned with the customers’ expectations. Traditionally the load cases for NVH development are focused only on quietness of passengers’ cabin at idling and in 3rd gear wide open throttle cruising on smooth roads. In reality, the Driver of a premium sedan car or a Sports Utility Vehicle (SUV) or a Compact Utility Vehicle (CUV) expects something different than merely the low sound pressure level inside the cabin. His/her driving pattern over a day plays a crucial role. A vehicle-owner wishes to balance various attributes of the in-cab sound and tactile vibrations at a time.