Muffler arrangements and methods

• US 6,334,506 B1
• Filed: 08/10/2000
• Issued: 01/01/2002
• Est. Priority Date: 08/10/2000
• Status: Expired due to Fees

• Current Assignee: Donaldson Company Incorporated
• Original Assignee: Donaldson Company Incorporated
• Inventors: Jones, Matthew W., Hamrin, John E.
• Primary Examiner(s): Nappi, Robert E.
• Assistant Examiner(s): LOCKETT, KIMBERLY R
• Application Number:
  US09/637,099
• Time in Patent Office: 509 Days
• Field of Search: 181/272, 181/269, 181/282, 181/255, 181/249
• US Class Current: 181/249
• CPC Class Codes: F01N 1/02 by using resonance
• CPC Class Codes: F01N 2470/02 Tubes being perforated
• CPC Class Codes: F01N 2470/04 characterised by shape, disposition or dimensions of apertures
• CPC Class Codes: F01N 2470/30 Tubes with restrictions, i.e. venturi or the like, e.g. for sucking air or measuring mass flow
• CPC Class Codes: F01N 2490/02 Two or more expansion chambers in series connected by means of tubes
• CPC Class Codes: F01N 2490/155 being disposed one after the other in flow direction
• CPC Class Codes: F01N 2490/20 Chambers being formed inside the exhaust pipe without enlargement of the cross section of the pipe, e.g. resonance chambers

Abstract

A muffler for use with heavy duty trucks includes an outer wall defining an internal volume; an inlet tube oriented at least partially within the internal volume; an outlet tube construction oriented at least partially within the internal volume and including a diverging section and a choke extension; and a first baffle structure securing the outlet tube construction within the internal volume. A ratio of the diverging section axial length to the choke extension axial length is preferably less than 3:1. The first baffle structure defines an aperture arrangement therein to permit gas flow communication therethrough. A ratio of the total open area of the aperture arrangement to the perimeter, cross-sectional area of the first baffle structure is between 1:50 and 1:500. The mufflers are particularly useful for attenuating low frequency noise associated with the internal volume of cabs or sleepers in heavy duty trucks.

Claims

1. A muffler arrangement comprising:

(a) an outer wall defining an internal volume and having first and second, opposite ends;

said outer wall having an outer dimension of at least 9.5 inches and an axial length between said first and second ends of less than or equal to 60 inches;

(b) an inlet tube construction oriented at least partially within said internal volume and adjacent to said first end;

(c) an outlet tube construction oriented at least partially within said internal volume and adjacent to said second end;

said outlet tube construction including a diverging section and a choke extension;

(i) said choke extension being oriented between said inlet tube and said diverging section;

(ii) said diverging section having first and second, opposite ends and a diverging section axial length;

(iii) said choke extension having first and second, opposite ends and a choke extension axial length;

(iv) a ratio of said diverging section axial length to said choke extension axial length being less than 3;

1; and

(d) a first baffle structure circumscribing said outlet tube construction within said internal volume;

said first baffle structure defining an outlet tube aperture circumscribing said outlet tube construction and a bleed aperture arrangement therein to permit gas flow communication therethrough;

(i) said bleed aperture arrangement having a total open area;

(ii) said first baffle structure having a perimeter, cross-sectional area; and

(iii) a ratio of said total open area of said bleed aperture arrangement to said perimeter, cross-sectional area of said first baffle structure being between 1;

500 and 1;

50.

2. A muffler arrangement according to claim 1 wherein:

(a) a ratio of said diverging section axial length to said choke extension axial length is less than 2.5;

1; and

(b) said outer wall has an outer dimension of no greater than 12 inches.

3. A muffler arrangement according to claim 2 wherein:

(a) a ratio of said total open area of said bleed aperture arrangement to said perimeter, cross-sectional area of said first baffle structure is between 1;

400 and 1;

200.

4. A muffler arrangement according to claim 3 wherein:

(a) said diverging section includes perforations; and

(b) said first baffle structure is secured to said outer wall and divides said internal volume between an inlet volume and an outlet volume;

(i) said aperture arrangement permitting gas flow communication between said inlet volume and said outlet volume.

5. A muffler arrangement according to claim 4 further including:

(a) an inlet baffle structure securing said inlet tube within said inlet volume; and

(b) an outlet baffle structure;

said first baffle structure and said outlet baffle structure securing said outlet tube construction within said outlet volume.

6. A muffler arrangement according to claim 5 wherein:

(a) said diverging section first end is immediately adjacent to said choke extension second end; and

said diverging section second end is immediately adjacent to said outlet baffle structure; and

(b) the muffler arrangement further includes a bell immediately adjacent to said choke extension first end.

7. A muffler arrangement according to claim 6 wherein:

(a) said inlet tube includes a full choke.

8. A muffler arrangement according to claim 7 wherein:

(a) said inlet tube includes a non-crimped construction.

9. A muffler arrangement according to claim 7 wherein:

(a) said inlet tube includes a crimped construction.

10. A muffler arrangement according to claim 7 wherein:

(a) said choke extension axial length is at least 15 inches;

(b) said diverging section axial length is no greater than 12 inches;

(c) said outer wall has a nominal diameter of 11 inches; and

(d) said choke extension is non-perforated.

11. A muffler arrangement according to claim 10 wherein:

(a) a ratio of said diverging section axial length to said choke extension axial length is less than 0.67;

1.

12. A muffler arrangement according to claim 7 wherein:

(a) said choke extension axial length is at least 7 inches;

(b) said diverging section axial length is no greater than 30 inches; and

(c) said outer wall has a nominal diameter of 10 inches.

13. A muffler arrangement according to claim 12 wherein:

(a) said choke extension is non-perforated.

14. A muffler arrangement according to claim 13 wherein:

(a) a ratio of said diverging section axial length to said choke extension axial length is less than 1;

1.

15. A muffler arrangement according to claim 12 further including:

(a) a first, inner perforated wall spaced from said outer wall and defining a first, annular volume therebetween;

(b) a first region of packing material positioned within said first annular volume;

(c) a second, inner wall spaced from at least a portion of said choke extension and defining a second annular volume therebetween; and

(d) a second region of packing material positioned within said second annular volume.

16. A muffler arrangement according to claim 15 wherein:

(a) said choke extension includes perforations; and

(b) a ratio of said diverging section axial length to said choke extension axial length is less than 1;

1.

17. A truck having:

(a) an engine rated for operation, at a rated rpm at a selected rpm value of 1800 or above, for a power of at least 300 hp; and

(b) an exhaust muffler system including at least one vertical muffler;

each vertical muffler of said exhaust system including;

(i) a cylindrical outer shell defining an internal volume;

said shell having an outside diameter of at least 9.5 inches and an overall length of no greater than 60 inches;

(ii) an inlet tube construction oriented at least partially within said internal volume;

(iii) an outlet tube construction oriented at least partially within said internal volume;

said outlet tube construction including a diverging section and a choke extension;

(A) said choke extension being oriented between said inlet tube and said diverging section;

(B) said diverging section having first and second, opposite ends and a diverging section axial length;

(C) said choke extension having first and second, opposite ends and a choke extension axial length;

(D) a ratio of said diverging section axial length to said choke extension axial length being less than 3;

1; and

(iv) a first baffle structure circumscribing said outlet tube construction within said internal volume;

said first baffle structure defining an outlet tube aperture circumscribing said outlet tube construction and a bleed aperture arrangement therein to permit gas flow communication therethrough;

(A) said bleed aperture arrangement having a total open area;

(B) said first baffle structure having a perimeter, cross-sectional area; and

(C) a ratio of said total open area of said bleed aperture arrangement to said perimeter, cross-sectional area of said first baffle structure being between 1;

50 and 1;

500.

18. A method of muffling an engine rated for operation, at a rated rpm at a selected rpm value of 1800 or above, for a power of at least 300 hp;

the method comprising;

(a) directing exhaust gas flow from the engine into a muffler;

the muffler including;

(i) a cylindrical outer shell defining an internal volume;

the shell having an outside diameter of at least 9.5 inches and an overall length of no greater than 60 inches;

(ii) an inlet tube construction oriented at least partially within the internal volume;

(iii) an outlet tube construction oriented at least partially within the internal volume;

the outlet tube construction including a diverging section and a choke extension;

(A) the choke extension being oriented between the inlet tube and the diverging section;

(B) the diverging section having first and second, opposite ends and a diverging section axial length;

(C) the choke extension having first and second, opposite ends and a choke extension axial length;

(D) a ratio of the diverging section axial length to the choke extension axial length being less than 3;

1; and

(iv) a first baffle structure circumscribing the outlet tube construction within the internal volume;

said first baffle structure defining an outlet tube aperture circumscribing said outlet tube construction and a bleed aperture arrangement therein to permit gas flow communication therethrough;

(A) the bleed aperture arrangement having a total open area;

(B) the first baffle structure having a perimeter, cross-sectional area; and

(C) a ratio of the total open area of the bleed aperture arrangement to the perimeter, cross-sectional area of the first baffle structure being between 1;

50 and 1;

500.