Acoustics – Sound-modifying means – Muffler – fluid conducting type
Reexamination Certificate
1999-10-21
2001-04-24
Nappi, Robert E. (Department: 2837)
Acoustics
Sound-modifying means
Muffler, fluid conducting type
C181S227000, C181S228000, C181S240000, C181S255000
Reexamination Certificate
active
06220387
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
The present invention relates generally to mufflers for attenuating the sound produced by the exhaust from internal combustion engines. More specifically, the present invention relates to mufflers that accelerate the flow of exhaust gases from internal combustion engines.
BACKGROUND OF THE INVENTION
In recent years, it has become increasingly necessary to provide improved mufflers for the attenuation of the exhaust noise produced by internal combustion engines used in transportation vehicles, due to public outcry and the resulting government regulations. New regulations are almost continually being proposed which require ever more stringent noise standards.
Many types of exhaust systems utilizing combinations of headers, collectors, and mufflers, as well as other noise reducing devices have been developed to address this problem. One type of exhaust system, generally referred to as a collector, combines and directs exhaust gases from separate exhaust tubes into a common downstream exhaust pipe. An exhaust muffler is attached downstream of the outlet pipe of the collector to effect noise reduction of the exhaust gases. Additionally, a catalytic converter may be attached to the exhaust system to convert some of the pollutants of the exhaust gases into harmless compounds. Unfortunately, such collector/muffler/catalytic converter systems are not very effective at minimizing the complexity of the exhaust system due to their many separate components. Moreover, they create back pressure which results in reduced performance of the engine. This reduced performance, or reduced horsepower, is undesirable in most vehicles.
Some muffler systems include sound attenuating material disposed in an space defined by an interior casing, or a tube structure, and an outer casing of the muffler. Holes or perforations in the interior casing, or tube structure, provide paths for the transmission of reflected high frequency components of noise into the sound attenuating material so that the noise can be subsequently dissipated. Unfortunately, this sound absorbing material adds to the overall weight of the muffler system, restricts the flow of exhaust, and provides a medium for the buildup of heat.
Thus, what is needed is An exhaust muffler that is lightweight, inexpensive, durable under attack of hot and corrosive exhaust gases, and impervious to vibration. Moreover, what is needed is An exhaust muffler that provides efficient noise attenuation while not causing undue back pressure to the engine, that is, one that provides good muffling without degrading engine performance.
SUMMARY OF THE INVENTION
Accordingly, it is an advantage of the present invention to provide an exhaust muffler for an internal combustion engine.
Another advantage of the present invention is to provide an exhaust muffler that accelerates the extraction of exhaust gases from the engine.
Another advantage of the present invention is to provide an exhaust muffler that achieves a cooling effect on the muffler and subsequently the engine.
Yet another advantage of the present invention is to provide an exhaust muffler that is economical in construction, lightweight, reliable in operation, rugged and able to withstand automotive racing along with normal use for extended periods.
The above and other advantages of the present invention are carried out in one form by An exhaust muffler for an internal combustion engine. The muffler includes a tapered tube having an exhaust inlet end exhibiting a first diameter and an exhaust outlet end exhibiting a second diameter, the second diameter being less than the first diameter. The exhaust inlet end is configured to receive exhaust gases from the engine. An outer tube is axially aligned with and surrounds the tapered tube to form an annular passage between the tapered tube and the outer tube. The outer tube has an air inlet end and an air outlet end. The air inlet end is configured to receive air external to the engine to create an air flow in the annular passage for accelerating the receipt of exhaust gases from the engine.
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Hoppes Mathew S.
Oster Aaron C.
Smith Timothy L.
Gresham Lowell W.
Lockett Kim
Meschkow Jordan M.
Meschkow & Gresham P.L.C.
Nappi Robert E.
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