Active sound attenation system for engine exhaust systems and the like

Claim 2

An active noise suppression system for exhaust of a combustion engine comprising: an exhaust transfer pipe, coupled to the combustion engine and having first and second ends, for transferring exhaust gas in a first direction from the combustion engine to ambient atmosphere, said first end receiving the exhaust gas from the combustion engine and said second end emitting the exhaust gas to the ambient atmosphere; an anti-noise chamber, annularly surrounding an outer periphery of said exhaust transfer pipe and having an outlet open to the ambient atmosphere adjacent said second end of said exhaust transfer pipe, for projecting anti-noise sound waves through said outlet to the ambient atmosphere; an anti-noise speaker, mounted to said anti-noise chamber for communication therewith, for generating and projecting said anti-noise sound waves into said anti-noise chamber to cancel noise generated by the combustion engine exhaust; separation means for isolating said anti-noise chamber from exhaust gas.

Claim 3

An active noise suppression system according to claim 1 further comprising another anti-noise speaker, said anti-noise speakers being disposed on said anti-noise chamber at opposed axial positions with respect to said exhaust transfer pipe upstream of said second end of said exhaust transfer pipe.

Claim 4

An active noise suppression system according to claim 2, wherein said anti-noise chamber is acoustically tuned and has a large diameter section joined to a smaller diameter section, said anti-noise speakers being mounted to said large diameter section, said smaller diameter section extending along said exhaust transfer pipe to said second end.

Claim 5

An active noise suppression system according to claim 3, wherein a front end of said large diameter section is closed off by an annular plate connected to an outer position of said exhaust transfer pipe, an outlet end of said smaller diameter section serving as said outlet of said anti-noise chamber which is supported from said exhaust transfer pipe by radially extending support plates.

Claim 6

An active noise suppression system according to claim 1, wherein said anti-noise chamber is symmetrically configured with respect to a longitudinal axis through a center of said exhaust transfer pipe.

Claim 7

An active noise suppression system according to claim 5, wherein said exhaust transfer pipe and said anti-noise chamber are cylindrical and concentric with respect to said longitudinal axis.

Claim 8

An active noise suppression system according to claim 1, further comprising a cooling chamber, disposed annularly between said exhaust transfer pipe and said anti-noise chamber, for drawing cooling air from the ambient atmosphere into said exhaust transfer pipe to cool said exhaust gas within said exhaust transfer pipe, said separation means comprising an outer wall of said cooling chamber.

Claim 9

The active noise suppression system according to claim 7, wherein said cooling chamber draws cooling air inward from adjacent said second end of said exhaust transfer pipe to flow in a second direction opposite the flow of exhaust gas through said exhaust transfer pipe in said first direction.

Claim 10

An active noise suppression system according to claim 8, wherein said exhaust transfer pipe has air flow openings for passing said cooling air from said cooling chamber into said exhaust transfer pipe, said air flow openings being symmetrically disposed about a circumference of said exhaust transfer pipe.

Claim 11

An active noise suppression system according to claim 9, wherein said air flow openings comprised of at least four separate radial openings.

Claim 12

An active noise suppression system according to claim 9, wherein said air flow openings are comprised of eight separate radial openings.

Claim 13

The active noise suppression system according to claim 1, wherein said combustion engine is an internal combustion engine.

Claim 14

An active noise suppression system according to claim 12, wherein the combustion engine being a driving engine for a motor boat.

Claim 15

An active noise suppression system according to claim 12, wherein the combustion engine is a driving engine for a motorized road passenger vehicle.

Claim 16

An active noise suppression system according to claim 1, wherein the combustion engine has an exhaust pipe for delivering the exhaust gas to said first end of said exhaust transfer pipe, said first end of said exhaust transfer pipe being insertable into said exhaust pipe and permanently affixable thereto by clamping seal means.

Claim 17

An active noise suppression system according to claim 15, wherein said exhaust transfer pipe, said anti-noise chamber and said anti-noise speakers are integrally constructed within a unitary sheet metal housing.

Claim 18

The active noise suppression system of claim 1, wherein said separation means comprises an outer wall of said exhaust transfer pipe.

Claim 19

An active noise suppression system for exhaust of a combustion engine comprising: an exhaust transfer pipe, coupled to the combustion engine and having first and second ends, for transferring exhaust gas in a first direction from the combustion engine to ambient atmosphere, said first end receiving exhaust gas from the combustion engine and said second end emitting the exhaust gas to the ambient atmosphere; passive noise reduction means surrounding an outer periphery of said exhaust transfer pipe, for reducing noise generated by the combustion engine and exhaust gas turbulence by cooling the exhaust gas within said exhaust transfer pipe; active noise reduction means for attenuating noise generating by the combustion engine and exhaust, said active noise reduction means comprising an anti-noise chamber surrounding an outer periphery of said passive noise reduction means, having an outlet port open to the ambient atmosphere adjacent said second end of said exhaust transfer pipe, for projecting anti-noise sound waves through said outlet port to the ambient atmosphere, an anti-noise speaker, mounted to said anti-noise chamber, for generating and projecting said anti-noise sound waves into said anti-noise chamber to further reduce noise generated by the combustion engine and exhaust; and separation means for isolating said anti-noise chamber from exhaust gas.

Claim 20

An active noise suppression system for exhaust of a combustion engine comprising: an exhaust transfer pipe, coupled to the combustion engine and having first and second ends, for transferring exhaust gas in a first direction from the combustion engine to ambient atmosphere, said first end receiving exhaust gas from the combustion engine and said second end emitting the exhaust gas to the ambient atmosphere; passive noise reduction means surrounding an outer periphery of said exhaust transfer pipe, for reducing noise generated by the combustion engine and exhaust gas turbulence by cooling the exhaust gas within said exhaust transfer pipe; active noise reduction means for attenuating noise generating by the combustion engine and exhaust, said active noise reduction means comprising an anti-noise chamber surrounding an outer periphery of said passive noise reduction means, having an outlet port open to the ambient atmosphere adjacent said second end of said exhaust transfer pipe, for projecting anti-noise sound waves through said outlet port to the ambient atmosphere, an anti-noise speaker, mounted to said anti-noise chamber, for generating and projecting said anti-noise sound waves into said anti-noise chamber to further reduce noise generated by the combustion engine and exhaust; and separation means for isolating said anti-noise chamber from exhaust gas.

Claim 21

The active noise suppression system of claim 18, further comprising plural anti-noise speakers mounted to said anti-noise chamber.

Claim 22

The active noise suppression system of claim 18, wherein said passive noise reduction means comprises a cooling chamber having an outlet end open to the ambient atmosphere for drawing inward cooling air from the ambient atmosphere.

Claim 23

The active noise suppression system of claim 20, wherein exhaust transfer pipe has air flow openings arranged around an outer periphery thereof near said first end for drawing said cooling air from said cooling chamber into said exhaust transfer pipe to reduce turbulence of the exhaust gas to reduce noise.

Claim 24

The active noise suppression system of claim 18, wherein said exhaust transfer pipe is provided with air flow openings communications with said passive noise reduction means.

Claim 25

The active noise suppression system of claim 21, wherein said exhaust transfer pipe, cooling chamber, anti-noise chamber and anti-noise speakers are integrally constructed within a unitary sheet metal housing.

Claim 26

The active noise suppression system of claim 23, wherein said combustion engine has an exhaust pipe for delivering the exhaust gas to said first end of said exhaust transfer pipe, said first end being insertable into said exhaust pipe and affixable thereto permanently by sealing clamp means.

Claim 27

The active noise suppression system of claim 18, wherein said anti-noise chamber is acoustically tuned and comprises a first section of large diameter coupled to a second section of smaller diameter, said anti-noise speakers comprising two speakers mounted to an outer periphery of said first section 180° apart from each other.

Claim 28

The active noise suppression system of claim 18, wherein said exhaust transfer pipe, passive noise reduction means, active noise reduction means and anti-noise speakers are integrally constructed within a unitary sheet metal housing.

Claim 29

The active noise suppression system of claim 18, wherein said separation means comprises an outer wall of said passive noise reduction means.

Claim 30

An integrally housed anti-noise suppression system comprising: an exhaust transfer pipe having first and second ends, for transferring exhaust gas in a first direction from a combustion engine to ambient atmosphere, said first end receiving exhaust gas from an exhaust pipe of the combustion engine and said second end emitting the exhaust gas to the ambient atmosphere; an anti-noise chamber, surrounding an outer periphery of said exhaust transfer pipe and having an outlet port open to the ambient atmosphere adjacent said second end of said exhaust transfer pipe, for projecting anti-noise sound waves through said outlet to the ambient atmosphere; an anti-noise speaker, mounted to an outer periphery of said anti-noise chamber, for generating and propagating said anti-noise sound waves into said anti-noise chamber to cancel noise generated by said combustion engine and said exhaust pipe; and separation means for isolating said anti-noise chamber from exhaust gas, said exhaust transfer pipe, anti-noise chamber and anti-noise speakers are constructed and integrally housed within a sheet metal structure.

Claim 31

An integrally housed anti-noise suppression system comprising: an exhaust transfer pipe having first and second ends, for transferring exhaust gas in a first direction from a combustion engine to ambient atmosphere, said first end receiving exhaust gas from an exhaust pipe of the combustion engine and said second end emitting the exhaust gas to the ambient atmosphere; an anti-noise chamber, surrounding an outer periphery of said exhaust transfer pipe and having an outlet port open to the ambient atmosphere adjacent said second end of said exhaust transfer pipe, for projecting anti-noise sound waves through said outlet to the ambient atmosphere; an anti-noise speaker, mounted to an outer periphery of said anti-noise chamber, for generating and propagating said anti-noise sound waves into said anti-noise chamber to cancel noise generated by said combustion engine and said exhaust pipe; and separation means for isolating said anti-noise chamber from exhaust gas, said exhaust transfer pipe, anti-noise chamber and anti-noise speakers are constructed and integrally housed within a sheet metal structure.

Claim 32

The integrally housed anti-noise suppression system of claim 28, wherein, said first end of said exhaust transfer pipe is insertable and permanently affixable by clamp sealing means to said exhaust pipe.

Claim 33

The integrally housed anti-noise suppression system of claim 29, further comprising: a cooling chamber, disposed annularly between said exhaust transfer pipe and said anti-noise chamber and having an outlet end open to the ambient atmosphere, for drawing cooling air inward from the ambient atmosphere, said separation means comprising an outer wall of said cooling chamber.

Claim 34

The integrally housed anti-noise suppression system of claim 30, wherein said cooling air is drawn into said cooling chamber in a second direction opposite to said first direction of exhaust gas flow within said exhaust transfer pipe.

Claim 35

The integrally housed anti-noise suppression system of claim 28, further comprising an additional anti-noise speaker mounted to an outer periphery of said anti-noise chamber, wherein said anti-noise chamber is acoustically tuned and has a first section of large diameter coupled to a second section of smaller diameter, said anti-noise speakers operatively coupled to an outer periphery of said first section 180° apart from each other.

Claim 36

The integrally housed anti-noise suppression system of claim 31, wherein said separation means comprises an outer wall of said exhaust transfer pipe.