الفهرس 
Chapter (1): IntroductionOnly 14 pages are availabe for public view
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Abstract
Automotive engine exhaust noise is considered to be one of the biggest sources of vehicle exterior noise. Further reduction of noise automotive exhaust system is still required, to fulfil the vehicle exterior noise regulations. Design of a complete muffler system is usually, a very complex task because each of its elements is selected by considering its particular acoustic performance and its interaction effects on the entire acoustic system performance. To properly design exhaust muffler systems, the interest to optimize the muffler performance in terms of sound transmission loss and pressure DROP which affect the engine fuel consumption are needed. Therefore, this thesis is grouped into four parts, acoustic modelling, experimental measurements, a parametric design optimization and selecting and testing the optimized muffler. Firstly; the mathematical models of different muffler configurations were completely represented. Secondly; the mathematical models were verified by comparing with the experimental results. Thirdly; a methodology to efficiently optimize the muffler configurations to maximize their acoustic performance in terms of sound transmission loss and pressure DROP at different mean flow speeds is presented. Finally; new optimized muffler is proposed and used to study the acoustic performance of four-cylinder diesel engine and compared with its performance using the existing muffler. It has been shown that the new optimized muffler reduces the engine exhaust noise around 6.8 per cent, and also reduces the brake specific fuel consumption of the same engine about 6 per cent at same operating conditions.