The exhaust silencer plays a very critical function to muffle the noise coming from the blasts inside a combustion engine .It is also used to cleanse the exhaust gases with the support of a catalytic converter. Get far more information about fan silencers
The exhaust design,as you might have noticed,features a bulge towards the end. The reason behind creating this bulge should be to deliver a larger cavity for the exhaust gases to flow,this mellows the sound coming directly from the engine and works around the principle of a Helmholtz resonator.
One other design form, that my physics teacher taught me about ,contains splitting the exhaust stream into two using the support of a secondary channel emerging from the pipe after which reconnecting it back .the length of this secondary channel is such that when the two sound streams meet again ,they are 180 degrees out of phase with respect to each other,this causes destructive interference at this junction! Therefore muffling the sound.
The catalytic converter catalyzes the redox reaction of ‘carbon monoxide-hydrocarbons’(ox) and ‘nitrogen oxides’(red) ,which essentially helps in converting pollutants to significantly less dangerous gases.
