Reductant decomposition system

Patent metadata

Field	Value
Publication number	US-9849424-B2
Application number	US-201414199089-A
Country	US
Kind code	B2
Filing date	Mar 6, 2014
Priority date	Apr 2, 2009
Publication date	Dec 26, 2017
Grant date	Dec 26, 2017

Abstract

Described herein are various embodiments of a reductant decomposition system. According to one representative embodiment, the reductant decomposition system includes an exhaust gas chamber including an inlet and outlet. The system also includes a first exhaust gas distribution component positioned within the chamber and communicable in exhaust gas receiving communication with the outlet. The first exhaust gas distribution component causes swirling exhaust gas flow patterns within the exhaust gas chamber. Additionally, the system includes a second exhaust gas distribution component positioned within the chamber and communicable in exhaust gas providing communication with the inlet. The second exhaust gas distribution component includes features that cause a swirling exhaust gas flow pattern within a space defined by the second exhaust gas distribution component. Further, the system includes a reductant injector coupled to the exhaust gas chamber. The reductant injector is communicable in reductant injecting communication with exhaust gas within the chamber.

First claim

What is claimed is:

1. A method for decomposing urea into ammonia, comprising:
passing exhaust gas through a first tubular exhaust distribution component and into a decomposition chamber, the decomposition chamber having a non-cylindrical shape with a curved edge transitioning from a side wall to a top wall of the decomposition chamber, the top wall of the decomposition chamber having a first height proximate the first tubular exhaust gas distribution component, the first tubular exhaust distribution component extending into the decomposition chamber from an inlet and having a perforation pattern on a sidewall surface, the perforation pattern causing the exhaust gas to swirl within the decomposition chamber;
injecting urea into the exhaust gas within the decomposition chamber to form an exhaust gas and urea mixture, the injected urea downstream of the first tubular exhaust distribution component; and
passing the exhaust gas and urea mixture within the decomposition chamber through a second tubular exhaust distribution component, the top wall of the decomposition chamber having a second height proximate the second tubular exhaust gas distribution component, the second height being smaller than the first height, the second tubular exhaust gas distribution component defined by a first end, a second end, and a curved tubular sidewall surface extending between the first end and the second end, the second tubular exhaust gas distribution component extending into the decomposition chamber from an outlet and having a plurality of circumferential blades formed in the curved tubular sidewall surface of the second tubular exhaust distribution component to swirl the exhaust gas and urea mixture within an interior volume of the second tubular exhaust distribution component, the second tubular exhaust distribution component downstream of the injected urea, the plurality of circumferential blades directing the exhaust gas and urea mixture to enter through slots at an angle relative to a radial direction of the second tubular exhaust gas distribution component to direct flow of the exhaust gas and urea mixture in a circular swirling pattern about a central axis of the second tubular exhaust distribution component effectively increasing a distance the exhaust gas and urea mixture travels relative to linear flow along an axial length of the second tubular exhaust gas distribution component.

2. The method of claim 1 , wherein the perforation pattern comprises a plurality of first perforations each having a first size and a plurality of second perforations each having a second size larger than the first size, wherein passing the exhaust gas through the perforation pattern of the first tubular exhaust distribution component comprises passing exhaust gas through the first and second perforations.

3. The method of claim 1 , wherein passing the exhaust gas through the perforation pattern of the first tubular exhaust distribution component causes the exhaust gas to swirl prior to passing between the plurality of circumferential blades and wherein passing the exhaust gas and urea mixture between the plurality of circumferential blades causes the exhaust gas and urea mixture to swirl after passing between the plurality of circumferential blades.

4. The method of claim 1 , wherein the plurality of circumferential blades are positioned about the central axis, the method further comprising directing a portion of exhaust gas radially inward toward the central axis after the exhaust gas passes between the plurality of circumferential blades.

5. The method of claim 4 , further comprising directing a portion of exhaust gas radially outward away from the central axis after the exhaust gas passes between the plurality of circumferential blades.

6. The method of claim 1 , wherein the decomposition chamber is within an end cap.

7. The method of claim 1 , wherein the first tubular exhaust distribution component is positioned downstream of an inlet to the decomposition chamber and the second tubular exhaust distribution component is disposed upstream of an outlet of the decomposition chamber.

8. The method of claim 1 , wherein the first tubular exhaust distribution component comprises a cylindrical tube, wherein the perforation pattern comprises a plurality of first perforations on a first portion of the sidewall surface of the cylindrical tube and each having a first size and a plurality of second perforations on a second portion of the sidewall surface of the cylindrical tube and each having a second size different from the first size.

9. The method of claim 8 , wherein the perforation pattern comprises a plurality of third perforations on an end of the cylindrical tube opposite an inlet, the plurality of third perforations having a third size different from the second size and the first size.

10. The method of claim 1 , wherein the second tubular exhaust distribution component comprises a contraction tube, the plurality of circumferential blades forming a plurality of slots through the contraction tube.

11. A reductant decomposition system, comprising:
a decomposition chamber having an inlet and an outlet on a side of the decomposition chamber, the decomposition chamber having a non-cylindrical configuration;
a first tubular exhaust distribution component extending into the decomposition chamber from the inlet and having a plurality of perforations on a sidewall surface configured to induce a first mixing pattern to exhaust gas entering the decomposition chamber via the inlet with both clockwise and counterclockwise vortical flow;
a second exhaust distribution component defined by a first end, a second end, and a curved tubular sidewall surface extending between the first end and the second end, the second tubular exhaust distribution component extending into the decomposition chamber from the outlet and having a plurality of blades and slots on the curved tubular sidewall surface of the second tubular exhaust distribution component configured to induce a second mixing pattern to an exhaust gas and urea mixture exiting the decomposition chamber via the outlet with a vortical flow within an interior of the second tubular exhaust distribution component upstream of the outlet of the decomposition chamber, the plurality of blades directing the exhaust gas and urea mixture to enter through the slots at an angle relative to a radial direction of the second tubular exhaust gas distribution component to direct the vortical flow of the exhaust gas and urea mixture about a central axis of the second tubular exhaust distribution component in a circular direction effectively increasing a distance the exhaust gas and urea mixture travel relative to linear flow along an axial length of the second tubular exhaust gas distribution component; and
an injector for injecting urea into the exhaust gas within the decomposition chamber while the exhaust gas is mixing via the first mixing pattern and upstream of the second tubular exhaust distribution component;
wherein the decomposition chamber has a top wall having a first height proximate the first tubular exhaust gas distribution component and a second height proximate the second tubular exhaust gas distribution component, the second height being less than the first height.

12. The reductant decomposition system of claim 11 , wherein the plurality of perforations are disposed on the circumferential surface of a tube extending from the inlet into an interior volume of the decomposition chamber, and wherein the plurality of blades and slots are disposed on the curved tubular sidewall surface extending from the outlet into the interior volume of the decomposition chamber.

13. The

Assignees

• Cummins Filtration Ip Inc
• Cummins Emission Solutions Inc

Inventors

• Davidson Debbie
• Engeham Duncan
• Uban Piotr
• Elsey David
• Liu Z Gerald
• Pawson Kenneth
• Smith Paul
• Capel Ken
• Critchley Andrew
• Sarcona David
• Goss James

Classifications

• Y02T10/24

  Cross-Sectional Technologies · mapped topic

• F01N3/2066 Primary

  Selective catalytic reduction [SCR] · CPC title

• F01N2610/02

  the substance being ammonia or urea · CPC title

• F01N2610/10

  the substance being heated, e.g. by heating tank or supply line of the added substance · CPC title

• B01D53/9495 Primary

  Controlling the catalytic process · CPC title