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With the stringent legislative requirements for noise in automobiles, gensets etc., the concern for properly designed silencers for specific applications is increasing. Optimized design of silencer requires an integrated study of acoustical and engine performance viz. Insertion loss and backpressure. However, the insertion loss itself depends upon engine characteristics geometry indicated by the transmission loss, flow induced noise, type of silencer - reactive, absorptive, hybrid, etc. Most of the work till date covers the acoustical and engine performance in isolation rather than in an integrated fashion due to the multidisciplinary nature of the problem. The objective of this study is to develop an integrated methodology to predict the performance of the silencer at the design stage resulting in an optimized time and cost effective design. In the present study, the acoustical and engine performance of silencer was predicted using FEM/BEM and CFD techniques.

The latest requirements for automotive cabin comfort require lower sound levels inside the cabin. There are many sources contributing to this noise of which fan is an important one. The blade passage noise of the cooling fan is often unpleasant and it is generally expensive to build and test different prototypes for optimum noise performance. Also, traditional unsteady computational approaches for predicting the fan noise are time and resource consuming and do not fit within the design cycle time. This paper proposes use of a steady state computational technique to predict the fan noise performance which provides for effective design study with optimum resources. The steady state data is used with the wave analogy to predict the overall sound pressure level. First, the computational results were validated with the experimental data for a base case and then parametric study was carried out to have optimum design.

The transportation noise is one of the major sources of noise exposure in residential areas and causes substantial annoyance particularly during night. Considering this, many countries have enacted legislation limiting the noise levels in residential areas and also the noise levels emitted by vehicles. In India also, the Ministry of Environment and Forests enacted Environment (Protection) Rules through Air Pollution Act in 1986. Various international as well as Indian standards for vehicles consider two types of noise measurement viz., Pass-By Noise (PBN) and Stationary Noise (SN). There is a debate going on whether in-use vehicle noise should be considered as a parameter for the Inspection and Maintenance (I&M) regime, which is to be introduced shortly in India. A detailed study was conducted to understand the relation between PBN and SN for both new and in-use vehicles.

Accelerated life evaluation of vehicle has become the order of the day with the continuously decreasing development time for product development. With the rapid progress in the computer aided design area, today it is possible to feed-in virtual test tracks so that even before a prototype is made, a life estimate could be arrived at. Further, the advent of rapid prototyping has also resulted in reducing the time required for development of prototypes considerably. This has put the proving engineers under tremendous pressure in reducing the time required for design validation. This has resulted in a number of techniques being developed for reducing number of tests required as well as test duration in validation of the prototypes. One such technique is non-square matrix simulation. This technique can also be used for the investigation of failures and validation of the modifications.

With increasing competition and number of global players entering the Indian market, the Indian tractor scenario is as hot and fluid as that of the passenger car. Tractor manufacturers are under tremendous market pressure to become internationally competitive and bring out new tractor models in the shortest time possible as well as keeping the validation costs to a minimum. This is making them to look for advanced techniques for reducing the development time such as service load data acquisition and analysis, life prediction and accelerated simulation tests for design validation. This paper presents such an effort by an Indian tractor manufacturer along with ARAL Design validation of the chassis was carried out as a complete structure instead of carrying out on individual components.

With a number of vehicles being developed in the country and implementation of safety standards becoming mandatory, proving of a vehicle for safety is becoming an area of high priority in India. Keeping this in view, a gravity sled facility has been established at ARAI for simulated crash testing. This paper describes the facility and its establishment as well as the development of suitable stopping devices to meet various applications. The risk of injury to the occupants in the event of crash is severe when structural deformation/breakage occurs in the vehicle interior, seat anchorages and the restraint systems. A simulated crash test facility such as sled is used for the development of these systems and their evaluation. This is the prescribed procedure for certification. Instead of using a complete vehicle crash facility, use of a simulated crash facility becomes cost effective. The simulated crash facility described here uses the gravity principle for acceleration of sled.

There are many aspects of engineering integrity which require careful consideration during design, manufacture, operation and maintenance of the complex systems such as automobile. The ultimate realisation of the “goals of design” implies successful service during the entire life of the product. There is tremendous pressure to utilise lighter materials which results in fuel saving. Assessing the engineering integrity of components and systems under service conditions can be extremely complex and prognostic situation at design stage is often more difficult than the diagnostic one once failure has occurred. Review of various advanced techniques with case studies have been done for the safety and reliability of automobiles for Indian conditions.