The noise from an exhaust system consists of three components: Pulsation noise and flow
generated noise coming from the orifice of the muffler outlet and shell noise coming from the shell of the muffler. Shell noise may be limited by using a stiffer or damped shell, while flow generated noise, such as turbulence and vortex shedding may be limited by minimizing geometrical discontinuities (edges, sharp bends etc.
Minimizing pulsation noise, caused by the valves opening and closing inside the IC engine, is the focus of this paper and this is obtained by designing the internal parts of the muffler in such a way that the most critical part of the frequency spectrum is attenuated.