Dr B.Venkataraman , Gokul Raj
An internal combustion engine produces excessive exhaust noise. A good exhaust system should control and keep the exhaust noise within the passable limit. Passive noise control techniques are employed to control the exhaust noises. Mufflers acts as a passive noise control elements in an exhaust system which attenuates noise by reflecting the sound wave and cancels it by destructive interferences and by absorbing the sound and dissipate into heat using absorptive materials .The muffler using absorptive materials for attenuating noise can cover a wide range of higher frequencies creating less back pressure while a reflection type muffler works well in lower and mid range frequencies but produces higher back pressure. This papers discusses the experimental results and performance evaluation of both absorption and reflective mufflers which are calculated by sound transmission loss (STL) experiment technique .
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