Interference-based exhaust noise attenuation

• US 20050279569A1
• Filed: 06/22/2004
• Published: 12/22/2005
• Est. Priority Date: 06/22/2004
• Status: Active Grant

• Current Assignee: Gregory Leigh Harris
• Original Assignee: Gregory Leigh Harris
• Inventors: Harris, Gregory Leigh
• Granted Patent: US 7,380,635 B2
• Time in Patent Office: Days
• US Class Current: 181/250
• CPC Class Codes: F01N 1/06 by using interference effect
• CPC Class Codes: F01N 1/12 using spirally or helically shaped channels cyclones B04C

Abstract

An interference-based exhaust noise attenuation device and method for exhaust flow from an internal combustion engine that generates compressive waves in the exhaust flow. The device includes at least a direct path for the exhaust flow; a looped path for the exhaust flow, with volumes of the direct path and the looped path differing by an amount that results in a staggered rearrangement of the compressive waves in the paths; a splitter that splits the exhaust flow into the direct path and the looped path; and a merger that merges the exhaust flow from the direct path and the looped path. When the exhaust flow from the direct path and the looped path are merged, at least some noise cancellation occurs. In other embodiments, plural direct paths, looped paths, splitters, and/or mergers can be used in various combinations.

Claims

1. An interference-based exhaust noise attenuation device for exhaust flow from an internal combustion engine that generates compressive waves in the exhaust flow, comprising:

a direct path for the exhaust flow;

a looped path for the exhaust flow, with volumes of the direct path and the looped path differing by an amount that results in a staggered rearrangement of the compressive waves in the paths;

a splitter that splits the exhaust flow into the direct path and the looped path; and

a merger that merges the exhaust flow from the direct path and the looped path;

wherein when the exhaust flow from the direct path and the looped path are merged, at least some noise cancellation occurs due to the staggered rearrangement caused by the differing volumes between the direct path and the looped path.

2. A device as in claim 1, wherein the merger is connected directly or through a duct to a muffler.

3. A device as in claim 1, wherein the amount that the volumes of the direct path and the looped path differ is equal to the displacement volume of one of the cylinders divided by four.

4. A device as in claim 1, wherein the looped path includes a helical portion.

5. A device as in claim 4, wherein the looped path is formed from two hollow curved half-tubes that when welded together form a single tube curved into a true helix.

6. A device as in claim 1, wherein the looped path is formed from joining two J-bent tubes.

7. A device as in claim 1, wherein the direct path and the looped path are parallel at least just after the splitter.

8. A device as in claim 1, wherein the direct path and the looped path are parallel at least just before the merger.

9. A device as in claim 1, wherein the splitter and the merger are connected by a straight tube to form the direct path.

10. A device as in claim 1, wherein the splitter and the merger are connected directly together to form the direct path.

11. An interference-based exhaust noise attenuation device for exhaust flow from an internal combustion engine that generates compressive waves in the exhaust flow, comprising:

one or more direct paths for the exhaust flow;

one or more looped paths for the exhaust flow, with volumes of the direct paths and the looped paths differing by amounts that result in staggered rearrangements of the compressive waves in the paths;

one or more splitters that splits the exhaust flow into the direct paths and the looped paths; and

one or more mergers that merge the exhaust flow from the direct paths and the looped paths;

wherein when the exhaust flow from the direct paths and the looped paths are merged, at least some noise cancellation occurs due to the staggered rearrangements caused by the differing volumes between the direct paths and the looped paths.

12. A method of interference-based exhaust noise attenuation for exhaust flow from an internal combustion engine that generates compressive waves in the exhaust flow, comprising:

splitting the exhaust flow into a direct path and a looped path with a splitter, with volumes of the direct path and the looped path differing by an amount that results in a staggered rearrangement of the compressive waves in the paths; and

merging the exhaust flow from the direct path and the looped path with a merger;

wherein when the exhaust flow from the direct path and the looped path are merged, at least some noise cancellation occurs due to the staggered rearrangement caused by the differing volumes between the direct path and the looped path.

13. A method as in claim 12, wherein the merger is connected directly or through a duct to a muffler.

14. A method as in claim 12, wherein the amount that the volumes of the direct path and the looped path differ is equal to the displacement volume of one of the cylinders divided by four.

15. A method as in claim 12, wherein the looped path includes a helical portion.

16. A method as in claim 15, wherein the looped path is formed from two hollow curved half-tubes that when welded together form a single tube curved into a true helix.

17. A method as in claim 12, wherein the looped path is formed from joining two J-bent tubes.

18. A method as in claim 12, wherein the direct path and the looped path are parallel at least just after the splitter.

19. A method as in claim 12, wherein the direct path and the looped path are parallel at least just before the merger.

20. A method as in claim 12, wherein the splitter and the merger are connected by a straight tube to form the direct path.

21. A method as in claim 12, wherein the splitter and the merger are connected directly together to form the direct path.

22. A method of interference-based exhaust noise attenuation for exhaust flow from an internal combustion engine that generates compressive waves in the exhaust flow, comprising:

splitting the exhaust flow into one or more direct paths and one or more looped paths with one or more splitters, with volumes of the direct paths and the looped paths differing by amounts that results in staggered rearrangements of the compressive waves in the paths; and

merging the exhaust flow from the direct paths and the plural looped paths with one or more mergers;

wherein when the exhaust flow from the direct paths and the looped paths are merged, at least some noise cancellation occurs due to the staggered rearrangements caused by the differing volumes between the direct paths and the looped paths.