Mufflers are devices installed within the exhaust system of most internal combustion engines to reduce the noise created by the engine. Mufflers may be broadly classified into two types based on the method by which they attenuate the engine noise. First being reflective type which works by the principle of destructive interference of acoustic pressure waves while the second type absorbs the acoustic energy of the exhaust resulting in noise reduction.
To study the contribution of each, Design of Experiments (DOE) was carried out for individual elements. Based on this, prototypes were manufactured to accommodate different configuration changes specified in the DOE. For all the prototypes, Insertion Loss (IL) and Transmission Loss (TL) tests are conducted and the results are analyzed to yield the contribution of each acoustic element towards the overall exhaust noise attenuation by the muffler of interest.
An advanced integrated muffler is an acoustic filter which accommodates in it, the principles of both reflective and absorptive type. One such standard muffler for a particular category of engine was chosen and different acoustic contributors in the muffler were identified and listed.
Aim of this paper is to study the acoustic characteristics of different elements including catalytic converter of an Advanced Integrated muffler designed for a BS-III engine of 180 hp capacity.