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Engine noise is a major source of noise inside the vehicle compartment. Recently, the quietness of the occupant cabin has become an important dimension to the quality of product. OEMs are finding it challenging to meet the customer expectations for “Powerful yet quiet” attribute. Several focused studies have been made to reduce the under hood component noise in automobiles. This paper summarizes the optimization of the vibro-acoustic sensitivity (VAS) of the engine mounts of a small car engine. The contribution of each engine mount on the structure-borne noise transfer inside the cabin is the prime focus of this study. In the current analysis, the body side and engine side mounting bracket stiffness analyses are carried out to reduce the vibro-acoustic transfer. Experimental methods like conventional FRF, on-road data acquisition and physical prototyping have been used.

Vehicle NVH is one of the key parameters in defining the perception quality of a vehicle. Interior noise refinement is necessary from comfort point of view whereas exterior noise should also be controlled to meet the environmental legislations. The paper focuses on the NVH development of a new air intake system. The new air intake system is designed keeping in mind the targets for fuel efficiency, torque, power output and cost. For the said improvements, significant changes are incorporated in the air tank structure, runner and plenum designs. These changes are bound to impact the NVH performance. The air intake noise can broadly be classified into structural radiation and orifice noise. In the current scope of study, the radiated noise from the air intake system is investigated. To trouble shoot the structural radiation, techniques like Experimental Modal Analysis (EMA) and Finite element normal mode / frequency response analysis have been carried out.