Flow device for an exhaust system

Patent metadata

Field	Value
Publication number	US-9180407-B2
Application number	US-201313933471-A
Country	US
Kind code	B2
Filing date	Jul 2, 2013
Priority date	Dec 17, 2008
Publication date	Nov 10, 2015
Grant date	Nov 10, 2015

Abstract

A flow device for an exhaust system includes a body that defines an interior cavity. An exhaust inlet passage is disposed in the interior cavity. An exhaust outlet passage is disposed in the interior cavity so that at least a portion of the exhaust inlet passage circumferentially surrounds at least a portion of the exhaust outlet passage. A doser is adapted to inject reductants into the interior cavity of the body such that the reductants are injected in the same general direction as the direction of flow of the exhaust gases.

First claim

What is claimed is:

1. A method for mixing reductant in an exhaust stream using a mixing apparatus including a mixing tube defining a tube axis, the mixing apparatus also including a housing having a side wall that surrounds the tube axis and an end wall that is transverse relative to the tube axis, wherein the end wall is a first end wall, wherein the housing includes a second end wall opposite from the first end wall, wherein the side wall extends between the first and second end walls, wherein the mixing tube is straight and extends between the first and second end walls, and wherein the exhaust from the mixing tube is outletted from the housing through the second end wall, the apparatus defining a chamber defined in part by the end wall and in part by the side wall, the mixing tube having a constant diameter and having an exhaust entrance end positioned at the chamber at a location offset from the end wall, the apparatus further including a dispenser for dispensing reductant into the chamber, the dispenser being mounted to the end wall of the housing and having a dispensing end offset from the exhaust entrance end of the mixing tube in a direction toward the end wall of the housing such that an axial gap is defined within the chamber in an orientation along the tube axis between the dispensing end of the dispenser and the exhaust entrance end of the mixing tube, the reductant including ammonia or urea, the method comprising:
supplying exhaust into the chamber;
dispensing the reductant from the dispenser into the axial gap within the chamber;
carrying the reductant with the exhaust from the axial gap into the exhaust entrance end of the mixing tube; and
swirling exhaust flow about the tube axis within the mixing tube.

2. The method of claim 1 , wherein the reductant is dispensed along the tube axis from the end wall toward the exhaust entrance end of the mixing tube.

3. The method of claim 2 , wherein the reductant is dispensed along the tube axis by spraying the reductant along the tube axis in a direction extending from the end wall of the housing toward the exhaust entrance end of the mixing tube.

4. The method of claim 1 , further comprising swirling the exhaust within the chamber before the exhaust enters the mixing tube.

5. The method of claim 4 , wherein the exhaust is swirled about the tube axis within the chamber.

6. The method of claim 1 , wherein the exhaust flows in a first general direction along the tube axis when entering the chamber and flows in a second general direction when exiting the chamber through the mixing tube, the first general direction being opposite from the second general direction.

7. The method of claim 1 , wherein the exhaust is swirled as the exhaust enters the chamber.

8. The method of claim 1 , wherein the exhaust is swirled by a swirl structure that surrounds the mixing tube.

9. The method of claim 8 , wherein the swirl structure includes a plate defining a plurality of openings and flow deflection surfaces corresponding to the openings.

10. The method of claim 9 , wherein the deflection surfaces include scoops.

11. The method of claim 8 , wherein the swirl structure is provided at an inlet of the chamber.

12. The method of claim 8 , wherein the swirl structure includes a plurality of flow deflection surfaces.

13. The method of claim 1 , wherein the exhaust flows along an exterior of the mixing tube prior to entering the chamber.

14. The method of claim 1 , wherein the exhaust flows through an annular space that surrounds the mixing tube prior to entering the chamber.

15. The method of claim 14 , wherein the exhaust flows through a swirl structure provided at an interface between the annular space and the chamber.

16. The method of claim 1 , wherein a plurality of flow deflectors are positioned circumferentially about the tube axis and are configured for swirling exhaust flow within the chamber about the tube axis.

17. A method for mixing reductant in an exhaust stream using a mixing apparatus including a mixing tube defining a tube axis, the mixing apparatus also including a housing having a main body defining a side wall that surrounds the tube axis, the main body also including oppositely positioned first and second end walls between which the side wall extends, the first and second end walls being spaced-apart from one another along the tube axis, the housing having an inlet and an outlet, the inlet including an inlet pipe, the outlet extending along the tube axis outwardly from the second end wall, the mixing tube having an end positioned adjacent to and spaced from the first end wall, the apparatus further including a dispenser for dispensing reductant into the main body of the housing in a direction toward the end of the mixing tube, the dispenser being mounted to the first end wall of the housing and having a dispensing end that is outside of an interior of the mixing tube, the reductant including urea or ammonia, the method comprising:
supplying exhaust into the main body of the housing through the inlet pipe;
directing at least some of the exhaust to a region within the main body that is between the dispensing end of the dispenser and the end of the mixing tube;
dispensing the reductant from the dispenser into the region, the reductant being dispensed in a direction from the first end wall toward the end of the mixing tube;
passing the exhaust from the region into the end of the mixing tube;
swirling the exhaust within the mixing tube to mix the dispensed reductant with the exhaust; and
passing the exhaust including the reductant through the outlet; and wherein the exhaust flows along an exterior of the mixing tube prior to entering the region.

18. The method of claim 17 , further comprising swirling the exhaust within the region before the exhaust enters the mixing tube.

19. The method of claim 17 , wherein the exhaust reverses axial flow directions within the region.

20. The method of claim 19 , wherein the exhaust is swirled within the region by a swirl structure that surrounds the mixing tube.

21. The method of claim 20 , wherein the swirl structure includes a plate defining a plurality of openings and flow deflection surfaces corresponding to the openings.

22. The method of claim 21 , wherein the deflection surfaces include scoops.

23. The method of claim 20 , wherein the swirl structure includes a plurality of flow deflection surfaces.

24. The method of claim 20 , wherein the exhaust flows through an annular space that surrounds the mixing tube prior to being swirled at the region.

25. The method of claim 17 , wherein the exhaust flows through an annular space that surrounds the mixing tube prior to entering the region.

26. The method of claim 17 , wherein a plurality of flow deflectors are positioned circumferentially about the tube axis and are configured for swirling exhaust flow about the tube axis prior to the exhaust entering the mixing tube, the exhaust being swirled by the flow deflectors at a location within the housing adjacent to the first end wall of the main body of the housing.

27. A method for mixing reductant in an exhaust stream using a mixing apparatus including a mixing tube defining a tube axis, the mixing apparatus also including a housing having a main body defining a side wall that surrounds the tube axis, the main body also including oppositely positioned first and second end walls between which th

Assignees

• Donaldson Co Inc

Inventors

• De Rudder Korneel
• Schellens Bart
• Gil Antonio
• Degelin Nic

Classifications

• B01F5/0659

  Operations & Transport · mapped topic

• F01N3/2066 Primary

  Selective catalytic reduction [SCR] · CPC title

• F01N2470/22

  Inlet and outlet tubes being positioned on the same side of the apparatus · CPC title

• F01N2470/18

  the axis of inlet or outlet tubes being other than the longitudinal axis of apparatus · CPC title

• Y02T10/24

  Cross-Sectional Technologies · mapped topic