All-Terrain Vehicle (ATV) – NVH (Noise Vibration & Handling) Control

Good NVH is becoming must feature in recent commercial vehicles. One of the major discomforts caused to driver by Engine vibration during idling. The power train is suspended on the vehicle frame on several flexible mounts, whose purpose is to isolate the vibration between engine and frame. Total 6 different modes of Engine like roll, yaw, pitch and Vertical, lateral and longitudinal need to isolate. Engine mount stiffness and position is critical and need to have methodology to verify in early stage of designing [1].

In this paper, the stiffness and modulus of elasticity value of engine rubber mount is calculated experimentally by carrying out compressive test on UTM. Later, the critical frequency is found by carrying modal analysis on this engine mount through ANSYS. Also by doing calculation, the position of driver’s seat is found ensuring the minimum NVH condition.

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In this paper, Transfer Path Analysis (TPA) method has been used to reduce the vibration at the seat of an All

Terrain Vehicle (ATV). The vibration source considered is the engine. Modifications are made on an existing Baja roll cage and comparisons are made to the existing design to arrive at the optimized design.FE model of the roll cage is analyzed and experimental validation is done.Modifications in the Transfer Path change the vibration pattern at the receiver. The modifications include addition of new roll cage members and use of different cross sectional beams for the engine mount. These changes result in reduced transmission of vibration from the engine to the roll cage. The analysis has been done in three different RPM ranges of the engine in order to ensure that a particular modification gives good performance over the entire operating range of the engine.

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Nowadays, in automotive industry the vehicle design cycle is mainly ruled by the highly competitive nature of the market and the ever increasing customer demands and expectations. This challenges automotive manufacturers to achieve higher-quality products in ever shorter time frames, while at the same time, reduce the design costs. This can only be achieved when the design cycle takes place largely on the basis of virtual modeling and simulation such that the traditional test phase, which relies on expensive and time-consuming physical prototypes, can be drastically shortened. As a result, nowadays, each stage of the design cycle is supported by CAE (Computer Aided Engineering) methodologies which allow to predict various functional performance attributes, such as NVH (Noise, Vibration & Harshness), crashworthiness, etc. Moreover, researchers have developed many techniques to speed up the calculations, enabling efficient modification approaches and optimizations. This paper focuses on the vehicle interior NVH performance. For a vehicle body Finite Element (FE) model, a reduced formulation has been achieved by using the WBS (Wave-Based Substructuring) technique. More specifically, a modification approach has been applied that is based on the generation of bead patterns on a subcomponent that has been identified as critical for the NVH behavior. By combining the reduced structural model with an efficient ATV (Acoustical Transfer Vector) approach to predict the interior acoustics performance, one can efficiently evaluate the effect of structural modifications on the interior NVH levels, such that the global NVH behavior can be optimized. The main innovation introduced in this paper comprises the optimization of vehicle vibro-acoustics by making use of a structural optimization software in combination with an acoustic target function. Two different methodologies have been worked out, based on two strategies for bead pattern optimization. Finally, the optimized component has been evaluated in terms of radiated Sound Pressure Level (SPL) and manufacturability.

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