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Understanding Mufflers

Thanks to a muffler, our vehicles are not as noisy as they are supposed to be. Also called silencer in British English, it acts as a noise regulator that apparently reduces the sounds emitted by the exhaust of an internal combustion engine. The patent for this device was awarded to Milton O. Reeves and Marshall T. Reeves on May 11 1897, both inventors coming from Columbus, Indiana of the Reeves Pulley Company. It is registered in the US Patent Office with the application number 582485.

Although not designed to serve any primary exhaust function, mufflers are installed within the exhaust system of most internal combustion engines.  It is specifically engineered to act as an acoustic soundproofing device that functions to lessen the loudness of the sound pressure created by the engine. This mechanism is called acoustic quieting.

Majority of the sound pressure produced by the engine comes out of the vehicle via the same piping used by the silent exhaust gases absorbed by a series of passages and chambers lined with roving fiberglass insulation and resonating chambers. The resonating chambers are harmonically tuned to cause destructive interference, making the opposite sound waves that interact cancel each other out.

However, one unavoidable side effect of using muffler is an increase of back pressure that lowers engine efficiency. This is due to the fact that the engine exhaust share the same complex exit pathways built inside the muffler as the sound pressure that the muffler is designed to mitigate.

The positions of mufflers vary in different kinds of vehicles.
  • For cars, they are installed lengthwise underneath, blowing backwards at the rear, however, one may choose to put them to the sides before the rear wheels.
  • For large diesel-powered trucks, mufflers are mounted vertically behind the cab or crosswise under the front of the cab, blowing sideways.
  • For motorcycles, they are usually put beside the engine and rear wheel blowing backwards.  In more modern designs, the mufflers are situated under the seat blowing backwards from under the back seat (under-slung). This contemporary style was popularized by the Buell motorcycles, and by 2008, almost all manufacturers already began following the under-engine design as well. Back in the old days, motorcycle enthusiasts would sometimes call the muffler (exhaust silencer) such terms as "raygun", "drag pipes", "pea-shooter", or "hotdog-style" thanks for its long, straight cylindrical barrel that merged roundedly at each end into the pipe.

Thanks to the invention of the muffler, we all now enjoy rides with less noise, and even less hassle. For more information about mufflers, contact your local muffler specialists in Tampa.

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