Acoustics – Sound-modifying means – Muffler – fluid conducting type
Reexamination Certificate
1999-11-15
2001-10-02
Dang, Khanh (Department: 2837)
Acoustics
Sound-modifying means
Muffler, fluid conducting type
C181S273000, C181S275000, C181S282000
Reexamination Certificate
active
06296074
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to exhaust mufflers, and more particularly to sound-attenuating mufflers for internal combustion engines and other sources of pulsating gas flow with substantial acoustic energy transport.
BACKGROUND OF THE INVENTION
Most mufflers employ various types of baffles in order to diffuse the sound by sending the sound in many different non-cohesive directions. Many other mufflers use packing materials in order to absorb the sound within the packing material. Both of these methods accomplish noise reduction by absorbing sound energy or redirecting the sound energy to cause interference that results in an equalization of sound pressure highs and lows.
The problem with baffles and packing materials is that the baffles and packing materials tend to impede the flow of exhaust from an internal combustion engine thus causing back pressure to be applied to the engine. The more back pressure exerting on the engine, the less efficient the engine performs. Accordingly, performance mufflers are currently available which have lower back pressure thus enabling better engine performance. However, the performance mufflers are often considerably louder than mufflers employing baffles and packing materials.
In an attempt to obtain a muffler with both low back pressure and noise levels, electronic mufflers have come to the forefront. Besides being more expensive than non-electronic mufflers to manufacture, the electrical systems of the electronic mufflers have proven to be unreliable due to the harsh environment in which mufflers operate.
Accordingly, a need exists for an economical method and apparatus of reducing noise in an exhaust stream while causing very low back pressure and achieving adequate noise levels.
SUMMARY OF THE INVENTION
The present invention addresses the above need, as well as others, with a method and apparatus of reducing noise in an exhaust stream. In accordance with one embodiment of the present invention, there is provided a method that includes the step of directing the exhaust stream into an inlet aperture of a sound cancellation chamber. The method also includes reflecting sound in the sound cancellation chamber toward the inlet aperture of the sound cancellation chamber. Another step of the method includes spreading the exhaust stream radially toward a periphery of the sound cancellation chamber. Yet another step of the method includes collecting exhaust from the periphery of the sound cancellation chamber in an outlet collector ring. Moreover, the method includes directing the exhaust collected from the periphery of the sound cancellation chamber substantially circumferentially about the sound cancellation chamber toward an outlet aperture of the outlet collector ring.
Pursuant to another embodiment of the present invention, there is provided a method of reducing noise in an exhaust stream. One step of the method includes the step of splitting the exhaust stream into a first exhaust stream and a second exhaust stream that are substantially equal. The first exhaust stream is directed into a sound cancellation chamber on a common counter-flow centerline in a first flow direction. The second exhaust stream is directed into the sound cancellation chamber on the common counter-flow centerline in a second flow direction that is opposite to the first flow direction, such that the second exhaust stream meets the first exhaust stream at a noise cancellation center point on the common-flow centerline inside the first sound cancellation chamber. The exhaust is collected and expelled from the sound cancellation chamber.
Pursuant to a further embodiment of the present invention, there is provided a muffler for reducing noise in an exhaust stream. The muffler includes a sound cancellation chamber, a dividing inlet, and an outlet collector ring. The sound cancellation chamber includes a first major surface with a first intake aperture, a first peripheral edge, and first reflector walls operable to direct sound toward the first intake aperture. The sound cancellation chamber further includes a second major surface with a second intake aperture, a second peripheral edge, and second reflector walls operable to direct sound toward the second intake aperture. The dividing inlet is operable to receive the exhaust stream and split the exhaust stream into a first exhaust stream and a second exhaust stream. To this end, the dividing inlet includes a first inlet channel operable to direct the first exhaust stream into the first intake aperture of the sound cancellation chamber, and a second inlet channel operable to direct the second exhaust stream into the second intake aperture of the sound cancellation chamber. The outlet collector ring of the muffler is coupled to the first peripheral edge and the second peripheral edge of the sound cancellation chamber such that the outlet collector ring is operable to receive and expel exhaust from the sound cancellation chamber.
It is an object of the present invention to provide an improved method and apparatus for reducing noise in an exhaust stream.
It is also an object of the present invention to provide a new and useful method and apparatus for reducing noise in an exhaust stream.
It is another object of the present invention to provide a method and apparatus for reducing noise in an exhaust stream which causes very low back pressure to be exerted against the exhaust stream flow.
It is yet another object of the present invention to provide a method and apparatus for reducing noise in an exhaust stream that requires no electrical devices for adequate performance.
It yet a further object of the present invention to provide a method and apparatus for reducing noise in an exhaust stream which requires no moving parts for adequate performance.
Another object of the present invention is to provide a method and apparatus for reducing noise in an exhaust stream which requires no packing materials or baffles for adequate performance.
The above and other objects, features, and advantages of the present invention will become apparent from the following description and the attached drawings.
REFERENCES:
patent: 702031 (1902-06-01), Ronan
patent: 2484827 (1949-10-01), Harley
patent: 2853148 (1958-09-01), Billey
patent: 3009530 (1961-11-01), Cocklin
patent: 3948349 (1976-04-01), Bychinsky
patent: 4044203 (1977-08-01), Swinbanks
patent: 4108276 (1978-08-01), Hall et al.
patent: 4185715 (1980-01-01), Reu Boiu
patent: 4220219 (1980-09-01), Flugger
patent: 4424882 (1984-01-01), Moller
patent: 4467887 (1984-08-01), Vizard
patent: 4623035 (1986-11-01), Schad et al.
patent: 4809812 (1989-03-01), Flugger
patent: 4937872 (1990-06-01), Hopfield et al.
patent: 5060271 (1991-10-01), Geddes
patent: 5173577 (1992-12-01), Clegg et al.
patent: 5220137 (1993-06-01), Howerton et al.
patent: 5278913 (1994-01-01), Delfosse et al.
patent: 5304749 (1994-04-01), Crandell
patent: 5614699 (1997-03-01), Yashiro et al.
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