Mixer for a vehicle exhaust system

Patent metadata

Field	Value
Publication number	US-10337380-B2
Application number	US-201715643884-A
Country	US
Kind code	B2
Filing date	Jul 7, 2017
Priority date	Jul 7, 2017
Publication date	Jul 2, 2019
Grant date	Jul 2, 2019

Abstract

A vehicle exhaust system includes an outer housing defining an internal cavity surrounding an axis, an inlet baffle configured to direct engine exhaust gas into the internal cavity, and an injector that is configured to spray a fluid into the internal cavity to mix with engine exhaust gas. An inner wall is spaced radially inward of an inner surface of the outer housing to define a gap. The inner wall has an impingement side facing the axis and a non-impingement side facing the gap. At least one heat transfer element is positioned within the gap and in is contact with at least one of the inner surface of the outer housing and the non-impingement side of the inner wall to transfer heat through the inner wall to the impingement side to reduce spray deposit formation.

First claim

The invention claimed is:

1. A vehicle exhaust system comprising:
an outer housing defining an internal cavity surrounding an axis;
an inlet baffle configured to direct engine exhaust gas into the internal cavity;
an injector that is configured to spray a fluid into the internal cavity to mix with engine exhaust gas;
an inner wall spaced radially inward of an inner surface of the outer housing to define a gap, wherein the inner wall has an impingement side facing the axis and a non-impingement side facing the gap; and
at least one heat transfer element positioned within the gap and in contact with at least one of the inner surface of the outer housing and the non-impingement side of the inner wall such that engine exhaust gas is conducted through the gap to directly contact and heat the heat transfer element, the at least one heat transfer element to transfer heat through the inner wall to the impingement side to reduce spray deposit formation.

2. The vehicle exhaust system according to claim 1 wherein the at least one heat transfer element extends only partially about the axis.

3. The vehicle exhaust system according to claim 2 wherein the outer housing extends circumferentially around the axis located at a center of the outer housing, and wherein the inner wall extends only partially about the axis, and wherein the at least one heat transfer element extends a first circumferential length and the inner wall extends a second circumferential length, and wherein the first circumferential length extends one hundred and eighty degrees or less around the axis and the second circumferential length extends more than one hundred and eighty degrees around the axis and less than three hundred and sixty degrees about the axis.

4. The vehicle exhaust system according to claim 1 wherein the inlet baffle includes at least one inlet opening that at least partially overlaps the at least one heat transfer element such that engine exhaust gas is conducted through the at least one inlet opening to directly contact the at least one heat transfer element.

5. The vehicle exhaust system according to claim 4 wherein the at least one heat transfer element extends in a peripheral direction about the axis, and wherein the at least one inlet opening extends along a peripheral edge of the inlet baffle and overlaps an entire peripheral length of the at least one heat transfer element.

6. The vehicle exhaust system according to claim 5 wherein the inlet baffle includes at least one second inlet opening positioned adjacent to the injector to direct engine exhaust gas toward spray entering the internal cavity.

7. The vehicle exhaust system according to claim 6 wherein the inlet baffle includes a plurality of third inlet openings that are smaller than the first and second inlet openings, and which are positioned on the inlet baffle to reduce back pressure.

8. The vehicle exhaust system according to claim 1 wherein the at least one heat transfer element comprises a sheet metal heat exchanger including a plurality of folds spaced apart from each other and extending about an outer periphery of the inner wall.

9. The vehicle exhaust system according to claim 8 wherein an apex of one fold is in contact with the non-impingement side and an apex of an immediately adjacent fold is in adjacent to the inner surface of the outer housing.

10. The vehicle exhaust system according to claim 8 wherein the sheet metal heat exchanger is comprised of sheet metal including one or more of a roughened surface, micro ribs, divots, or turbulators.

11. The vehicle exhaust system according to claim 8 wherein the sheet metal heat exchanger is comprised of a sheet or layer of microporous material.

12. The vehicle exhaust system according to claim 1 wherein the at least one heat transfer element comprises metal foam or mesh that is attached to the non-impingement side of the inner wall.

13. The vehicle exhaust system according to claim 1 wherein the at least one heat transfer element comprises a coating applied to at least one of the inner surface of the outer housing or the non-impingement side of the inner wall to increase heat transfer to the impingement side of the inner wall.

14. The vehicle exhaust system according to claim 13 wherein the coating comprises a ceramic coating that is applied in a matrix or grid work pattern on the inner surface of the outer housing.

15. A mixer for a vehicle exhaust system comprising:
an outer housing defining an internal cavity surrounding a center axis;
an inlet baffle configured to direct engine exhaust gas into the internal cavity, wherein the inlet baffle includes at least one inlet opening formed along a periphery of the inlet baffle;
an injector mounted to the outer housing, the injector being configured to spray a fluid into the internal cavity to mix with engine exhaust gas;
an inner wall spaced radially inward of an inner surface of the outer housing to define a gap, wherein the inner wall has an impingement side facing the axis and a non-impingement side facing the gap; and
at least one heat transfer element positioned within the gap and in alignment with the at least one inlet opening such that engine exhaust gas is conducted through the at least one inlet opening to directly contact the at least one heat transfer element, the at least one heat transfer element being in contact with at least one of the inner surface of the outer housing and the non-impingement side of the inner wall such that the at least one heat transfer element transfers heat through the inner wall to the impingement side to reduce spray deposit formation.

16. The mixer for a vehicle exhaust system according to claim 15 wherein the at least one heat transfer element extends only partially about the axis, and wherein the inner wall extends only partially about the axis, and wherein the at least one heat transfer element is defined by a first circumferential length extending about the center axis and the inner wall is defined by a second circumferential length extending about the center axis that is greater than the first circumferential length.

17. The mixer for a vehicle exhaust system according to claim 16 wherein the at least one heat transfer element comprises a sheet metal heat exchanger including a plurality of folds spaced apart from each other and extending about an outer periphery of the inner wall, and wherein an apex of one fold is in contact with the non-impingement side and an apex of an immediately adjacent fold is adjacent to the inner surface of the outer housing.

18. The mixer for a vehicle exhaust system according to claim 16 wherein the sheet metal heat exchanger is comprised of sheet metal or a sheet of microporous material and includes one or more of a roughened surface, divots, micro ribs, or turbulators.

19. The mixer for a vehicle exhaust system according to claim 16 wherein the at least one heat transfer element comprises metal foam or mesh that is attached to the non-impingement side of the inner wall.

20. The mixer for a vehicle exhaust system according to claim 15 wherein the at least one heat transfer element comprises a coating applied to at least one of the inner surface of the outer wall or the non-impingement side of the inner wall to increase heat transfer to the impingement side of the inner wall.

21. The mixer for a vehicle exhaust system according to claim 15 wherein the at least one heat transfer element extends in a peripheral direction about the axis, and wherein the at least one inlet op

Assignees

• Faurecia Emissions Control Technologies Usa Llc

Inventors

• Willats Robin
• Hornback Jerome Brian
• Parrish Tony
• Rohde John G
• Ker Eric

Classifications

• F01N3/035

  with catalytic reactors · CPC title

• F01N2240/20

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• B01F5/0268

  Operations & Transport · mapped topic

• F01N3/2066

  Selective catalytic reduction [SCR] · CPC title

• F01N2610/1453

  Sprayers or atomisers; Arrangement thereof in the exhaust apparatus · CPC title