Patent US3744589A successfully refreshed from Google Patents.
US3744589A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Swirling flow muffler
Assignee: Motors Liquidation Co
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Filing: 1972-06-09
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Granted: 1973-07-10
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Expires: 1992-06-09
Abstract
Abstract In preferred form, a sound attenuating device receiving internal combustion engine exhaust gases including a closed cylindrical body having tangentially attached inlet and outlet ports providing unbaffled helical flow of the gases through the cylindrical body. A first layer of acoustical material is positioned within said closed cylindrical member in conformance to the interior surface thereof and can be spaced therefrom depending upon the particular material used. A second layer of acoustical material is concentrically disposed about a cylindrical resonator attached to one end of the closed cylindrical body. The second layer of acoustical material substantially conforms to the exterior surface of the resonator and can also be spaced therefrom depending upon the materials used. A perforated cylindrical member having a closed end is attached to the other end of the cylindrical body. The closed end of the perforated cylindrical member extends toward but is spaced from the end of the resonator which extends approximately half the axial length of the closed cylindrical body. Upon entrance into the inlet port, a substantial portion of the sound waves impinge against both layers of acoustical material so that both high frequency and medium frequency sound waves are absorbed by the material as the gases progress through the unbaffled helical flow path to the outlet port. The annulus itself is effective to cancel wavelengths associated with the circumferential distance. In addition, the muffler chamber exhibits lined expansion chamber noise reduction characteristics. This arrangement provides desirable sound attenuating results without creating a substantial pressure drop across the device.
Inventors
- 👤 R Mellin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 10:47
CPC Classifications
F; F01; F01N; F01N1/00; F01N1/02; F01N1/04; F01N1/08; F01N1/10; F01N2490/00; F01N2490/15
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
221 words
A sound attenuating device for an internal combustion engine characterized by low pressure drop thereacross comprising: means defining a generally cylindrical silencing chamber having end walls and a longitudinal axis; inlet and outlet conduits communicating with axially spaced points on said means and tangentially disposed with respect thereto adjacent the outer periphery thereof and extending into the interior of said body to direct exhaust gases from said engine in an unbaffled helical flow path through said chamber; a first cylindrical body of acoustical absorbing material coaxially disposed within said chamber and adjacent to the outer periphery of said chamber so that its inner periphery is exposed to sound waves in the flow path for absorbing the latter; and a second cylindrical body of acoustical absorbing material coaxial with said chamber and within said first mentioned body of acoustical absorbing material interiorly peripherally bounding the exhaust gas helical flow path on its outer surface to helically direct the gas flow against the interior surface of said first cylindrical body of acoustical material, the annular circumference being effective to attenuate related wavelength sound waves and said bodies of acoustical material being effective to absorb ranges of sound wavelengths in the high and medium portion of the frequency spectrum, whereby said device cancels a substantial portion of sound energy in the fluid pass therethrough.
Claim 2
Dependent Claim
221 words
A sound attenuating device for an internal combustion engine characterized by low pressure drop thereacross comprising: means defining a generally cylindrical silencing chamber having end walls and a longitudinal axis; inlet and outlet conduits communicating with axially spaced points on said means and tangentially disposed with respect thereto adjacent the outer periphery thereof and extending into the interior of said body to direct exhaust gases from said engine in an unbaffled helical flow path through said chamber; a first cylindrical body of acoustical absorbing material coaxially disposed within said chamber and adjacent to the outer periphery of said chamber so that its inner periphery is exposed to sound waves in the flow path for absorbing the latter; and a second cylindrical body of acoustical absorbing material coaxial with said chamber and within said first mentioned body of acoustical absorbing material interiorly peripherally bounding the exhaust gas helical flow path on its outer surface to helically direct the gas flow against the interior surface of said first cylindrical body of acoustical material, the annular circumference being effective to attenuate related wavelength sound waves and said bodies of acoustical material being effective to absorb ranges of sound wavelengths in the high and medium portion of the frequency spectrum, whereby said device cancels a substantial portion of sound energy in the fluid pass therethrough.
Claim 3
Dependent Claim
257 words
A sound attenuating device for an internal combustion engine characterized by low pressure drop thereacross comprising: means defining a generally cylindrical silencing chamber having end walls and a longitudinal axis; inlet and outlet conduits communicating with axially spaced points on said means and tangentially disposed with respect thereto adjacent the outer periphery thereof; a first cylindrical body of acoustical absorbing metal foam coaxial with said chamber and inside the same adjacent to and spaced from the outer periphery of said chamber so that its inner periphery is exposed to sound waves in the flow path for absorbing the latter; a second cylindrical body of acoustical absorbing metal foam interiorly peripherally bounding the exhaust gas helical flow path on its outer surface to direct the sound waves against the interior surface of said first cylindrical body of metal foam; said bodies consequently defining a flow path space therebetween and said inlet and outlet conduits extending into the interior of said first body directing exhaust gases from said engine in an unbaffled helical flow path through the space in said chamber; and a resonator member centrally disposed within said second cylindrical body and acoustically coupled to said cylindrical chamber, the annular circumferential path being effective to attenuate sound waves of related wavelength and said bodies of acoustical metal foam being effective to absorb high and medium frequency ranges of sound wavelengths; said resonator member further attenuating low frequency sound waves in the exhaust gases, whereby said device cancels a substantial portion of sound energy in the fluid passing therethrough.
Claim 4
Dependent Claim
257 words
A sound attenuating device for an internal combustion engine characterized by low pressure drop thereacross comprising: means defining a generally cylindrical silencing chamber having end walls and a longitudinal axis; inlet and outlet conduits communicating with axially spaced points on said means and tangentially disposed with respect thereto adjacent the outer periphery thereof; a first cylindrical body of acoustical absorbing metal foam coaxial with said chamber and inside the same adjacent to and spaced from the outer periphery of said chamber so that its inner periphery is exposed to sound waves in the flow path for absorbing the latter; a second cylindrical body of acoustical absorbing metal foam interiorly peripherally bounding the exhaust gas helical flow path on its outer surface to direct the sound waves against the interior surface of said first cylindrical body of metal foam; said bodies consequently defining a flow path space therebetween and said inlet and outlet conduits extending into the interior of said first body directing exhaust gases from said engine in an unbaffled helical flow path through the space in said chamber; and a resonator member centrally disposed within said second cylindrical body and acoustically coupled to said cylindrical chamber, the annular circumferential path being effective to attenuate sound waves of related wavelength and said bodies of acoustical metal foam being effective to absorb high and medium frequency ranges of sound wavelengths; said resonator member further attenuating low frequency sound waves in the exhaust gases, whereby said device cancels a substantial portion of sound energy in the fluid passing therethrough.
Claim 5
Dependent Claim
97 words
A sound attenuating device as described in claim 2 further comprising the resonator member being attached to one end of said means and extending substantially to the mid-portion of said silencing chamber; and a perforated second resonator member attached to the opposite end of said means and extending toward said resonator but terminating so as to provide a space therebetween; said resonators being acoustically coupled to said silencing chamber whereby said bodies of acoustical metal foam, the annular circumferential path and said resonators cooperate to substantially cancel the sound energy in exhaust gases flowing through said device.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-07-09 | 1977-01-08 | 1977-07-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-07-09 | 1981-01-08 | 1981-07-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-07-09 | 1985-01-08 | 1985-07-10 | $7700.00 | Window Closed / Lapsed |