Claims
- 1. An apparatus comprising:
- an internal combustion engine;
- an exhaust system through which exhaust gases from said engine exit to atmosphere; and
- a noise reduction apparatus for reducing the sound level of exhaust gases exiting said exhaust system, said noise reduction apparatus comprising:
- a housing mounted within said exhaust system so that exhaust gases can pass through said apparatus, said housing having an upstream end through which exhaust gases enter said apparatus and a downstream end through which exhaust gases exit said apparatus, and
- a plurality of tubular sound absorbing layers mounted within said housing so as to be radially spaced apart relative to one another, each of said plurality of sound absorbing layers having an upstream end, being sufficiently porous to allow exhaust gases to flow therethrough and being operatively adapted to absorb acoustical energy from exhaust gases coming in contact therewith,
- wherein said noise reduction apparatus is operatively adapted to allow at least some exhaust gases to flow therethrough relatively unrestricted, from one end of said noise reduction apparatus to the other, such as by not having to flow through a porous wall.
- 2. The apparatus of claim 1, said sound absorbing layers being mounted inside of said housing such that the upstream ends of said sound absorbing layers are longitudinally staggered relative to one another so as to generally define a truncated cone shape.
- 3. The apparatus of claim 1, said noise reduction apparatus having a central longitudinal axis and being operatively adapted to allow exhaust gases to flow along its central longitudinal axis relatively unrestricted, from one end of said noise reduction apparatus to the other, such as by not having to flow through a porous wall.
- 4. The apparatus of claim 1, further comprising a plurality of tubular sections mounted inside of said housing, each of said tubular sections having a porous wall, each of said sound absorbing layers being supported by at least one of said tubular sections, and said noise reduction apparatus being operatively adapted to allow exhaust gases to flow therethrough, from one end to the other, without having to flow through the porous wall of one of said tubular sections.
- 5. The apparatus of claim 1, each of said sound absorbing layers being made of an acoustical energy absorbing material in a form selected from the group consisting of acoustical energy absorbing particles, fiber, fabric and combinations thereof.
- 6. The apparatus of claim 1, said noise reduction apparatus further comprising a truncated cone-shaped element mounted inside of said housing with a tapering end disposed toward the downstream end of said housing, said truncated cone-shaped element having a porous wall adapted to allow exhaust gases to flow therethrough, and each of said sound absorbing layers being mounted radially outside of and so as to longitudinally overlap said truncated cone-shaped element.
- 7. The apparatus of claim 1, wherein each of said sound absorbing layers has a downstream end and said noise reduction apparatus further comprises a bracket mounted to said housing so as to maintain the downstream end of said sound absorbing layers radially spaced apart.
- 8. The apparatus of claim 7, wherein said bracket has a plurality of braces, each brace is in the form of a fin that is angled so as to direct exhaust gas, passing through the downstream end of said noise reduction apparatus, to spiral around the central longitudinal axis of said noise reduction apparatus.
- 9. The apparatus of claim 1, said noise reduction apparatus further comprising a spacer mounted within said housing so as to maintain the spacial relationship between said sound absorbing layers, said spacer comprising a plurality of fins mounted between said sound absorbing layers and being angled so as to direct exhaust gas, passing through said noise reduction apparatus, to spiral around the central longitudinal axis of said noise reduction apparatus as the exhaust gas passes through said noise reduction apparatus.
- 10. The apparatus of claim 1, said housing having an outer surface and an inner surface, and said noise reduction apparatus includes at least one layer of a viscous and/or elastic type material mounted on at least one of the outer surface or inner surface of said housing.
- 11. An internal combustion engine exhaust system through which exhaust gases from an engine exit to atmosphere, said exhaust system comprising:
- a noise reduction apparatus for reducing the sound level of exhaust gases exiting said exhaust system, said noise reduction apparatus comprising:
- a housing mounted within said exhaust system so that exhaust gases can pass through said apparatus, said housing having an upstream end through which exhaust gases enter said apparatus and a downstream end through which exhaust gases exit said apparatus, and
- a plurality of tubular sound absorbing layers mounted within said housing so as to be radially spaced apart relative to one another, each of said plurality of sound absorbing layers having an upstream end, being sufficiently porous to allow exhaust gases to flow therethrough and being operatively adapted to absorb acoustical energy from exhaust gases coming in contact therewith,
- wherein said noise reduction apparatus is operatively adapted to allow at least some exhaust gases to flow therethrough relatively unrestricted, from one end of said noise reduction apparatus to the other, such as by not having to flow through a porous wall.
- 12. The exhaust system of claim 11, said sound absorbing layers being mounted inside of said housing such that the upstream ends of said sound absorbing layers are longitudinally staggered relative to one another so as to generally define a truncated cone shape.
- 13. The exhaust system of claim 11, said noise reduction apparatus having a central longitudinal axis and being operatively adapted to allow exhaust gases to flow along its central longitudinal axis relatively unrestricted, from one end of said noise reduction apparatus to the other, such as by not having to flow through a porous wall.
- 14. The exhaust system of claim 11, further comprising a plurality of tubular sections mounted inside of said housing, each of said tubular sections having a porous wall, each of said sound absorbing layers being supported by at least one of said tubular sections, and said noise reduction apparatus being operatively adapted to allow exhaust gases to flow therethrough, from one end to the other, without having to flow through the porous wall of one of said tubular sections.
- 15. The exhaust system of claim 11, each of said sound absorbing layers being made of an acoustical energy absorbing material in a form selected from the group consisting of acoustical energy absorbing particles, fiber, fabric and combinations thereof.
- 16. The exhaust system of claim 11, said noise reduction apparatus further comprising a truncated cone-shaped element mounted inside of said housing with a tapering end disposed toward the downstream end of said housing, said truncated cone-shaped element having a porous wall adapted to allow exhaust gases to flow therethrough, and each of said sound absorbing layers being mounted radially outside of and so as to longitudinally overlap said truncated cone-shaped element.
- 17. The exhaust system of claim 11, wherein each of said sound absorbing layers has a downstream end and said noise reduction apparatus further comprises a bracket mounted to said housing so as to maintain the downstream end of said sound absorbing layers radially spaced apart.
- 18. The exhaust system of claim 17, wherein said bracket has a plurality of braces, each brace is in the form of a fin that is angled so as to direct exhaust gas, passing through the downstream end of said noise reduction apparatus, to spiral around the central longitudinal axis of said noise reduction apparatus.
- 19. The exhaust system of claim 11, said noise reduction apparatus further comprising a spacer mounted within said housing so as to maintain the spacial relationship between said sound absorbing layers, said spacer comprising a plurality of fins mounted between said sound absorbing layers and being angled so as to direct exhaust gas, passing through said noise reduction apparatus, to spiral around the central longitudinal axis of said noise reduction apparatus as the exhaust gas passes through said noise reduction apparatus.
- 20. The exhaust system of claim 11, said housing having an outer surface and an inner surface, and said noise reduction apparatus includes at least one layer of a viscous and/or elastic type material mounted on at least one of the outer surface or inner surface of said housing.
RELATED CASES
The present application is a continuation-in-part of Ser. No. 08/379,733, now U.S. Pat. No. 5,661,272, filed Jan. 27, 1995, issued Aug. 26, 1997, entitled ENGINE NOISE REDUCTION APPARATUS and having the same inventor as the present application.
US Referenced Citations (19)
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
379733 |
Jan 1995 |
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