The three most common types of mufflers are absorption muffler, diffusion muffler and a cancellation muffler.
The muffler is the part of a vehicle’s exhaust system that lessens the noise and reduces emissions created by the car’s engine. Another important function of the muffler is to allow exhaust waste to blow out of the internal combustion system of the vehicle’s engine. Without a muffler, a vehicle is extremely loud and releases unsafe emissions into the air. A vehicle with no muffler also builds up impurities in the engine which will cause it to work harder, yet less efficiently. The end result is that the engine will fail at a much faster rate.
An absorption muffler uses one straight perforated tube wrapped in a material that deafens sound. The exhaust emissions travel through the tube without resistance and the various frequencies are absorbed by the material surrounding the perforated tube. A diffusion muffler divides the flow of exhaust gases along a series of tubes, which are also known as baffles. Since the flow of exhaust follows a longer path it loses energy and the sound frequency is lowered.
Inlet and Outlet Pipes
Inlet and outlet pipes are short pipes that go into the main chamber of the muffler. They are perforated with thousands of tiny holes which let pressure pulses bounce around in the main chamber. Sound frequencies cancel each other out to some extent in addition to being absorbed by the muffler’s housing.
The Hemholtz chamber, invented by a German scientist, is also known as a resonating chamber. This type of muffler is rarely used alone. It usually functions along with one of the other two muffler types. Other names for the resonating chamber are back box or silencer. The hollow resonating chamber silences the loud noise which come the engine’s combustion system through a process known as destructive interference. Destructive interference basically means that the chamber uses the various vibrations and resonance from the engine against each other, resulting in the noise to canceling itself out.