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The increasing trends towards smaller power units running at high speeds together with the increasing use of diesel engines in passenger vehicles have resulted in higher vehicle interior noise and vibration levels. The customer awareness towards comfort of vehicle specifically with reference to perceived noise levels has become a selling point for vehicle manufacturers. In this paper experimental and analytical techniques used to study the influence of cabin related parameters on interior noise are presented. These techniques were applied to study interior noise of truck cabins. The noise and vibration signals were measured at body panels and at Operators Ear Location (OEL) for different engine speeds. The natural frequencies of body panels were identified by using frequency response function measurements. The modal analysis of acoustic cavity was carried out using finite element technique.

The air induction system of an automobile engine contributes to the noise level generated by a passenger car. The contribution is significant in the perception of vehicle noise quality. There is a great value in reducing and controlling passenger car air induction noise. Helmholtz resonators are widely used for noise reduction in vehicle induction and exhaust system. These resonators are usually mounted as side branch volumes to the main induction system, occupying larger space. The design presented here describes the use of compact inline Helmholtz resonator (Patent application no. 190/Bombay/98) for elimination of low frequency noise character in passenger car. Finite element model of the acoustic cavity of induction system along with the inline resonator is made. The transmission loss characteristics computed analytically correlates very well with the experimental transmission loss characteristics.

Torsional and lateral bending vibrations of cylinder block have a large effect on engine noise. Cylinder block vibration not only causes noise to radiate from the cylinder block itself but it is also the major exciting force to the oil pan and timing belt cover. In order to reduce engine noise, it is important to completely understand the mechanism of cylinder block vibrations. An analysis is conducted using FEM and BEM to compute the influence of crankshaft torsional vibrations on cylinder block vibrations. A crankshaft system for a four cylinder automobile engine was used for analysis. Finite Element model of crankshaft is created using parametric modelling software developed based on ANSYS FEA software. Finite Element model of cylinder block, bearing cap, oil sump is also created using another parametric software developed based on ANSYS FEA software.

The paper describes simulation of frontal barrier impact of a car body shell structure for crashworthiness analysis using non linear explicit finite element package LS-DYNA3D. Predicted overall collapse modes of different structural component viz.apron, side rails etc. are in a good agreement with published results and also to some extent with experimental results. In this paper crash analysis of above car structure with crash guard is simulated using LS-DYNA3D and comparative analysis of crash behaviour of car structure in the presence of crashguard is shown to indicate its possible role on crash behaviour of a vehicle.