Experimental NVH Studies on Electric Powered and IC Engine Powered Passenger Vehicles – A Comparative Study for NVH Target Setting

Presently, there is a tremendous pressure on the automotive OEMs to help reduce environmental pollution by reducing the tail pipe emissions. One of the major challenges faced by the Indian automotive OEMs, while meeting the upcoming BSVI emission regulations is the increase in product complexity and cost due to the addition of components such as urea tank, DPF and other miscellaneous engine components. It is seen in the recent past that, Indian government is making favorable moves in promoting the Electric Mobility and so most of the OEMs are presently working on converting their IC Engine powered vehicle platforms to Battery Powered vehicles. The present work focusses on experimental Noise Vibration and Harshness (NVH) studies on electric powered and IC Engine powered passenger vehicles. Though, there is a significant reduction in forcing functions in the Electric Vehicle (EV) due to the elimination of many sub-systems namely, IC Engine, multispeed transmission, intake and exhaust systems and center bearings, elimination of IC engine will expose the passengers to many of the secondary noises that were previously masked but will now annoy the occupant. The major noise sources in EV are motor noise, wind noise, tire/road noise, HVAC noise, battery cooling noise, squeaks & rattles, ancillary system noises and other unknow noise sources that were not apparent in the IC engine powered vehicles. In the present work, a comparative study (IC Engine versus EV) on the vehicle level NVH characteristics is performed and the strategies for EV - NVH reduction are discussed. A Methodology for "NVH Target Setting "while Converting IC Engine Powered Vehicle to EV is proposed.