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The automotive industry is one of the industries that have visibility suffered a strong demand for higher environmental performance. This industry have enjoyed years as the main source of employment and economic growth, today it is being pointed out as one of the major contributors to air pollution in urban centers. Indeed the benefits of automobile provide the means of gaining access to life's necessities and employment and a source of pleasure. However, despite these benefits there are environmental burdens as well: local air pollution, greenhouse gas emissions, road congestion, noise, mortality and morbidity from accidents and less open space to roads. Thus companies in the sector have been trying different strategies to overcome these challenges Evaluation of Emission development for commercial vehicles had always been great challenge to continuously migrate from one level of emission norm to other maintaining the business continuity.

In the automotive industry several attributes needs to be considered for the development of a new vehicle which are important for the customer, such as vehicle dynamics, driveability, fuel consumption, emissions, durability and NVH among many others. Sometimes these characteristics are conflicting and often need is to create a robust trade-off where the design space is sufficient to fit all of them in a vehicle that rhymes with the brand image and is appealing to the intended customer. Automobile manufacturers try to meet the requirements with respect to quality and comfort and often, emotional, aspects supercede the previous objective, pragmatic demands. The satisfaction of the demands by the customers concerning comfort, driving pleasure, design appears dominant and functionality criteria sometimes takes a back seat. NVH is considered to be one of the key buy in factor among the above mentioned attributes.

Mufflers are devices installed within the exhaust system of most internal combustion engines to reduce the noise created by the engine. Mufflers may be broadly classified into two types based on the method by which they attenuate the engine noise. First being reflective type which works by the principle of destructive interference of acoustic pressure waves while the second type absorbs the acoustic energy of the exhaust resulting in noise reduction. To study the contribution of each, Design of Experiments (DOE) was carried out for individual elements. Based on this, prototypes were manufactured to accommodate different configuration changes specified in the DOE. For all the prototypes, Insertion Loss (IL) and Transmission Loss (TL) tests are conducted and the results are analyzed to yield the contribution of each acoustic element towards the overall exhaust noise attenuation by the muffler of interest.

In recent years NVH has gained a lot of importance in the commercial vehicle industry as it contributes significantly towards user comfort and also towards the quality perception associated with a vehicle. The in-cabin noise of vehicles is critical towards the comfort and usability for the end user and the sound package installed on the vehicle plays a vital role in determining the levels associated with this attribute, especially the high frequency content. The paper discusses a methodology for optimizing the sound package for performance, cost and mass, for a truck. The approach uses a Statistical Energy Analysis (SEA) based optimization. A virtual SEA model is developed, which is correlated with actual test data. After establishing the correlation, an optimization study is carried out to identify the effectiveness of different materials and material combinations towards in-cabin noise.

Traditional methods of noise control in most application are by using absorption and barrier techniques. These involve brackets & clamps for assembly, carrier material to hold absorbing materials. Usage of absorbing materials which could be high, as this is based on noise control technique by allowing source to produce noise and hence the cost is also higher. Based on the survey, several demerits have been studied in using absorption and barrier noise control techniques in the field of an automobile application. This paper deals with the noise control by using the application of free layer damping technique thereby overcoming the demerits happening in using former techniques, helping better control of noise in the environment and solutions which are more durable. The methodology followed here before going for the FLD application is identification of noise radiating components which needs to be damped in a system or subsystem.