muffler, in automobiles, device designed to reduce the noise from the exhaust of an internal-combustion engine. When the exhaust gases from an internal-combustion engine are released directly into the atmosphere, they create a loud noise, caused by the passage of the exhaust gases from the high pressure of the cylinder to the normal pressure of the atmosphere. To eliminate or tone down the noise, the gases are led through a pipe to a muffler. Typically a muffler consists of a tubular metal jacket containing perforated pipes and chambers through which the exhaust gases flow before entering the atmosphere. The pipes and chambers are arranged so that the noise from the exhaust gases is reflected back toward the engine or back and forth among the chambers, reducing greatly the amount of noise that is radiated into the environment.

A muffler (or silencer in British English) is a device for reducing the amount of noise emitted by a machine. On internal combustion engines, the engine exhaust blows out through the muffler. The internal combustion engine muffler or silencer was developed in parallel with the firearm suppressor by Hiram Percy Maxim.

Description

Mufflers are typically installed along the exhaust pipe as part of the exhaust system of an internal combustion engine (of a vehicle, or stationary) to reduce its exhaust noise. The muffler accomplishes this with a resonating chamber, which is specifically tuned to cause destructive interference, where opposite sound waves cancel each other out.

Catalytic converters also often have a muffling effect. The effect is mainly generated largely by restriction, rather than by cancellation.

Advantages

Mufflers that reduced backpressure relative to earlier models became increasingly available in the late 20th century, and resulted in increased engine efficiency, performance, power output, and simultaneously decreased overall wear and tear on the engines' components, as well as sound to levels in compliance with the law.

Types and positions of mufflers

• With cars, lengthwise underneath, blowing backwards at the rear
• to the sides before the rear wheels.
• With large diesel-powered trucks:-
• Mounted vertically behind the cab
• Crosswise under the front of the cab, blowing sideways.
• With motorcycles:
• Usually, beside the engine and rear wheel blowing backwards.
• In more modern motorcycles, under the seat blowing backwards from under the back of the seat. (Under-slung)
• Under-engine exhausts first reached popularity with Buell motorcycles, though by 2008 most Japanese manufactures began using the under-engine design as well.

Motorcycle enthusiasts sometimes use the term "raygun," or "pea-shooter" for the old shape of motorcycle exhaust silencer/muffler with a long straight cylindrical barrel that merged roundedly at each end into the pipe, as in this image and this image

See also

• Exhaust system

References

External links

• Howstuffworks: "How Mufflers Work"
• Aero Performance Exhaust: Muffler Manufacturer

ru: Глушитель (акустический фильтр)