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T. Sreedhar et al.
slowly and to cool in the muffler. In various designs, the outer most shells of the
mufflers are made with an oval shape to allow sufficient clearance with the ground.
Most of the mufflers are provided with little channel gaps in the outside shell to drain
out the condensate from the exhaust gases and to oppose corrosion [1].
1.1 Types of Mufflers
• Baffle type
• Wave cancellation type
• Resonance type
• Absorber type
• Combined resonance and absorber type.
1.2 Rockwool Insulation
Rockwool was discovered on the islands of Hawaii, wherever it happens naturally
as a by-product of volcanic activity at the start of the twentieth century. Dielectric in
its manufactured state has non-directional fiber orientation and also the distinctive
characteristics of the stone. Dielectric is synthetic from liquefied rock in a chamber
through that a stream of an air temperature of concerning around 160 °C. The ultimate
product generates a mass of fine free fibers which have a loose-leaf folder and oil
to reduce dusting. Once ironed into reels and pieces their capability to partition air
makes them outstanding heat insulators and sound absorber.
2 Literature Survey
In Chen et al. [2], the compression ratio is altered to 17.5, the intake pipe and valve
are changed to 45 mm and 3°CA (backwards), the timing of the exhaust valve is
changed 3°CA (forward), and now, the new muffler is assembled. The results show
for the modified modelled and simulated that intake noise decreases 1.1–1.4 dB
and exhaust noise decreases 2.6–3 dB. Md. In Nasir et al. [3], the experiments on
the muffler tested with a 500KW load and 1800 RPM. It frequently causes duct
ion of exhaust gas flow noise. In Asutosh Prasad et al. [4], the experimental results
are stated that 2.5 dB minimum exhaust pressure is obtained at the tailpipe of the
reactive muffler and respective to the higher conduction loss of 90 dB which is
obtained with frequency 1350 Hz. In Crocker et al. [5], the coherence model has
allowed a rigorous determination of the attenuation (frequency response function
Hi) between individual cylinder pressures and engine noise. Previous attempts at
this must be regarded as approximate at best since only an “average” attenuation
T. Sreedhar et al.
slowly and to cool in the muffler. In various designs, the outer most shells of the
mufflers are made with an oval shape to allow sufficient clearance with the ground.
Most of the mufflers are provided with little channel gaps in the outside shell to drain
out the condensate from the exhaust gases and to oppose corrosion [1].
1.1 Types of Mufflers
• Baffle type
• Wave cancellation type
• Resonance type
• Absorber type
• Combined resonance and absorber type.
1.2 Rockwool Insulation
Rockwool was discovered on the islands of Hawaii, wherever it happens naturally
as a by-product of volcanic activity at the start of the twentieth century. Dielectric in
its manufactured state has non-directional fiber orientation and also the distinctive
characteristics of the stone. Dielectric is synthetic from liquefied rock in a chamber
through that a stream of an air temperature of concerning around 160 °C. The ultimate
product generates a mass of fine free fibers which have a loose-leaf folder and oil
to reduce dusting. Once ironed into reels and pieces their capability to partition air
makes them outstanding heat insulators and sound absorber.
2 Literature Survey
In Chen et al. [2], the compression ratio is altered to 17.5, the intake pipe and valve
are changed to 45 mm and 3°CA (backwards), the timing of the exhaust valve is
changed 3°CA (forward), and now, the new muffler is assembled. The results show
for the modified modelled and simulated that intake noise decreases 1.1–1.4 dB
and exhaust noise decreases 2.6–3 dB. Md. In Nasir et al. [3], the experiments on
the muffler tested with a 500KW load and 1800 RPM. It frequently causes duct
ion of exhaust gas flow noise. In Asutosh Prasad et al. [4], the experimental results
are stated that 2.5 dB minimum exhaust pressure is obtained at the tailpipe of the
reactive muffler and respective to the higher conduction loss of 90 dB which is
obtained with frequency 1350 Hz. In Crocker et al. [5], the coherence model has
allowed a rigorous determination of the attenuation (frequency response function
Hi) between individual cylinder pressures and engine noise. Previous attempts at
this must be regarded as approximate at best since only an “average” attenuation