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Three-cylinder Engine without balancer shaft is a recent trend towards development of lightweight and fuel-efficient powertrain for passenger car. In addition, customer's expectation of superior NVH inside vehicle cabin is increasing day by day. Engine mounts address majority of the NVH issues related to transfer of vibration from engine to passenger cabin. Idle vibration isolation for a three-cylinder engine is a challenging task due to possibility of overlapping of Powertrain's rigid body modes with engine's firing frequency. This Overlapping of rigid body can be avoided either by modifying mount characteristic or by changing the position of mounts based on multi-body-dynamics (MBD) simulation. This paper explains about two types of engine mounting system for a front-wheel drive transversely mounted three-cylinder engine. The base vehicle was having three-point mounting system i.e. all three engine mounts were pre-loaded.

The automobile market is witnessing a different trend altogether - the trend of shifting preference from powerful to fuel efficient machines. Certain factors like growing prices of fuel, struggling global economy, environmental sensitiveness and affordability have pushed the focus on smaller, efficient and cleaner automobiles. To meet such requirements, the automobile manufacturers, are going stringent on vehicle weights. Using electric and hybrid power-plants are other options to meet higher fuel efficiency and emission requirements but significant cost of these technologies have kept their growth restricted to only few makers and to only few regions of the globe. Optimizing the vehicle weight is a more attractive option for makers as it promises lesser time to market, is low on investment and allows use of existing platforms.

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.

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.

One of the most common NVH refinement areas of a vehicle is the cabin booming noise. The current study discusses the improvement of the low frequency booming noise in the cabin of a small passenger car. The practice of reinforcing experimental evaluation results with the extensive use of computer aided engineering tools in the development process is presented in this paper. The structural changes executed in the vehicle, to reduce noise contribution, are iterated and optimized using simulation and validated using experimental analysis methods like operational modal analysis, linear frequency response functions and actual run-up measurements. Additionally, the interesting variation of the NVH characteristics of a vehicle due to the changeover from a 4-cylinder inline to a 3-cylinder inline powertrain, while inheriting the similar body structure, is discussed in this study.