U.S. patent application number 12/828350 was filed with the patent office on 2010-10-21 for exhaust aftertreatment system with flow distribution.
This patent application is currently assigned to CUMMINS FILTRATION IP, INC.. Invention is credited to Jeffrey T. Sedlacek, Jay V. Warner.
Application Number | 20100263354 12/828350 |
Document ID | / |
Family ID | 39740258 |
Filed Date | 2010-10-21 |
United States Patent
Application |
20100263354 |
Kind Code |
A1 |
Sedlacek; Jeffrey T. ; et
al. |
October 21, 2010 |
Exhaust Aftertreatment System with Flow Distribution
Abstract
An exhaust aftertreatment system has a side inlet flow diffuser
and provides even flow exhaust distribution to an aftertreatment
element.
Inventors: |
Sedlacek; Jeffrey T.;
(Stoughton, WI) ; Warner; Jay V.; (Stoughton,
WI) |
Correspondence
Address: |
ANDRUS, SCEALES, STARKE & SAWALL, LLP
100 EAST WISCONSIN AVENUE, SUITE 1100
MILWAUKEE
WI
53202
US
|
Assignee: |
CUMMINS FILTRATION IP, INC.
Minneapolis
MN
|
Family ID: |
39740258 |
Appl. No.: |
12/828350 |
Filed: |
July 1, 2010 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
11684118 |
Mar 9, 2007 |
7748212 |
|
|
12828350 |
|
|
|
|
Current U.S.
Class: |
60/274 ;
60/324 |
Current CPC
Class: |
F01N 13/08 20130101;
Y10T 137/0318 20150401; Y10T 137/8593 20150401; F01N 2240/20
20130101; F01N 3/24 20130101 |
Class at
Publication: |
60/274 ;
60/324 |
International
Class: |
F01N 3/00 20060101
F01N003/00; F01N 1/00 20060101 F01N001/00 |
Claims
1-8. (canceled)
9. An exhaust aftertreatment system comprising an exhaust conduit
carrying exhaust to an aftertreatment element treating said
exhaust, said conduit comprising an L-shaped bend having first and
second legs meeting at an L-shaped junction, said second leg
extending axially along an axis along an axial direction and
directing exhaust to said aftertreatment element, said first leg
extending laterally along a lateral direction relative to said axis
and directing exhaust to said second leg, a flow distributor at
said L-shaped junction and re-distributing exhaust to flow from
said first leg to said second leg in an evenly distributed flow
pattern to flow axially along said second leg to said
aftertreatment element, wherein said flow distributor is a
perforated member having a variable perforation pattern, wherein
said flow distributor has an inlet end receiving exhaust flowing
laterally thereinto, and a distal end laterally distally oppositely
spaced from said inlet end, and said variable perforation pattern
provides a diffuser outlet flow area which decreases as exhaust
flows from said inlet end toward said distal end.
10. The exhaust aftertreatment system according to claim 9 wherein
said variable perforation pattern comprises decreasing density of
perforations from said inlet end toward said distal end.
11. The exhaust aftertreatment system according to claim 9 wherein
said variable perforation pattern comprises decreasing size of
perforations from said inlet end toward said distal end.
12-14. (canceled)
15. An exhaust aftertreatment device comprising a housing extending
axially along an axis and having an upstream inlet for receiving
exhaust and having a downstream outlet for discharging exhaust,
said inlet being a side inlet receiving exhaust flowing laterally
into said housing relative to said axis, an aftertreatment element
in said housing passing exhaust axially therethrough then to said
outlet, a flow distributor receiving exhaust flow laterally from
said inlet and re-distributing exhaust to flow axially to said
aftertreatment element in an evenly distributed flow pattern,
wherein said flow distributor comprises a perforated diffuser tube
having a variable perforation pattern providing a diffuser outlet
flow area which decreases as exhaust flows laterally away from said
inlet.
16. The exhaust aftertreatment device according to claim 15 wherein
said variable perforation pattern comprises decreasing density of
perforations as exhaust flows laterally away from said inlet.
17. The exhaust aftertreatment device according to claim 15 wherein
said variable perforation pattern comprises decreasing size of
perforations as exhaust flows laterally away from said inlet.
18. (canceled)
19. A method for optimizing exhaust flow distribution to an
aftertreatment element in an exhaust aftertreatment device
comprising a housing extending axially along an axis and having an
upstream inlet for receiving exhaust and having a downstream outlet
for discharging exhaust, said inlet being a side inlet receiving
exhaust flowing laterally into said housing relative to said axis,
and an aftertreatment element in said housing passing exhaust
axially therethrough then to said outlet, said method comprising
providing a diffuser tube extending downstream laterally away from
said inlet, providing said diffuser tube with a variable
perforation pattern providing a diffuser outlet flow area which
decreases as exhaust flows laterally away from said inlet, said
method further comprising optimizing even exhaust flow distribution
by decreasing at least one of density and size of perforations of
said variable perforation pattern as said diffuser tube extends
laterally away from said inlet to optimize and achieve even flow
distribution of exhaust flowing axially to said aftertreatment
element.
Description
BACKGROUND AND SUMMARY
[0001] The invention relates to aftertreatment systems for internal
combustion engine exhaust, and more particularly to flow
distribution.
[0002] To address engine emission concerns, new standards continue
to be proposed for substantial reduction of various emissions,
including NOx and particulate emissions. Increasingly stringent
standards will require installation of aftertreatment devices in
engine exhaust systems. Some of the aftertreatment technologies
require certain chemical species to be injected into the exhaust
system. For example, HC or fuel is injected in some active lean NOx
systems for NOx reduction, or in active diesel particulate filters
(DPF) for regeneration to take place (oxidizing the soot and
cleaning the filter), and urea solution is injected in selective
catalytic reduction (SCR) systems for NOx reduction. These injected
chemical species need to be well mixed with exhaust gas and evenly
distributed before reaching catalysts or filters for the systems to
perform properly.
[0003] The present invention arose during continuing development
efforts directed toward the above exhaust aftertreatment
systems.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] FIG. 1 is a side schematic sectional view of an exhaust
aftertreatment system in accordance with the invention.
[0005] FIG. 2 is similar to FIG. 1 and shows an alternate
embodiment.
[0006] FIG. 3 is like FIG. 2 and shows another alternate
embodiment.
DETAILED DESCRIPTION
[0007] FIG. 1 shows an exhaust aftertreatment system 10 including
an exhaust conduit or pipe 12 carrying internal combustion engine
exhaust from engine 14 and side inlet 16 to an exhaust
aftertreatment element 18 treating the exhaust, for example a
selective catalytic reduction (SCR) catalyst and/or an oxidation
catalyst (e.g. a diesel oxidation catalyst DOC). An injector 20 is
provided upstream of aftertreatment element 18 and injects chemical
species mixing with the exhaust prior to reaching aftertreatment
element 18. For example, in one embodiment aqueous urea solution is
injected from reservoir or tank 22. The exhaust conduit has an
L-shaped bend at 24 for the exhaust flow path, including first and
second legs 26 and 28 meeting at an L-shaped junction 30. Second
leg 28 extends axially along an axis 32 along an axial direction
and directing exhaust to aftertreatment element 18. First leg 26
extends laterally along a lateral direction 34 relative to axis 32
and directs exhaust to second leg 28. A flow distributor 36 is
provided at the noted L-shaped junction and distributes exhaust
flow from first leg 26 to second leg 28 in an evenly distributed
flow pattern 38 to flow axially along second leg 28 to
aftertreatment element 18.
[0008] In the preferred embodiment, flow distributor 36 is a
perforated member receiving exhaust flowing laterally along first
leg 26, and discharging the exhaust axially along second leg 28
through perforations 40. Flow distributor 36 has an inlet end 42
receiving exhaust flowing laterally thereinto, and has a distal end
44 laterally distally oppositely spaced from inlet end 42. Flow
distributor 36 has a cross-sectional flow area which decreases as
exhaust flows from inlet end 42 toward distal end 44. Inlet end 42
of flow distributor 36 has a first cross-sectional area lying in a
first plane which extends along an axial direction and along a
transverse direction, the transverse direction extending into the
page of FIG. 1, the transverse direction being normal to axial
direction 32 and normal to lateral direction 34. Flow distributor
36 has a second cross-sectional area at a point between inlet end
42 and distal end 44, with such second cross-sectional area lying
in a second plane which extends along axial direction 32 and along
the noted transverse direction into the page of FIG. 1. The noted
second plane is laterally spaced from the noted first plane. The
noted second cross-sectional area is less than the noted first
cross-sectional area. Flow distributor 36 is tapered along a
perforated sidewall 46 extending obliquely relative to each of the
noted axial and lateral directions 32 and 34, respectively. In the
preferred embodiment, flow distributor 36 is a conically shaped
diffuser tube pointing laterally away from inlet end 42, and
L-shaped bend 24 is 90.degree..
[0009] Exhaust conduit or housing 12 extends axially along the
noted axis 32 and has an upstream inlet at 16 for receiving exhaust
from engine 14, and has a downstream outlet at 48 for discharging
exhaust. Inlet 16 is a side inlet receiving exhaust flowing
laterally into housing 12 relative to axis 32. Aftertreatment
element 18 in the housing passes exhaust axially therethrough then
to outlet 48. Flow distributor 36 receives exhaust flowing
laterally from inlet 16 and re-distributes the exhaust to flow
axially to aftertreatment element 18 in an evenly distributed flow
pattern 38. As noted, flow distributor 36 is preferably a conically
shaped diffuser tube pointing downstream laterally away from the
inlet, and preferably includes a perforated sidewall which
conically convergingly tapers as it extends laterally away from the
inlet.
[0010] FIGS. 2 and 3 show alternate embodiments and use like
reference numerals from above where appropriate to facilitate
understanding.
[0011] In FIG. 2, flow distributor 50 is shown in elevation and is
a perforated member having a variable perforation pattern 52. Flow
distributor 50 has an inlet end 54 receiving exhaust flowing
laterally thereinto along the noted lateral direction 34, and has a
distal end 56 laterally distally oppositely spaced from inlet end
54. Variable perforation pattern 52 provides a diffuser outlet flow
area which decreases as exhaust flows from inlet end 54 toward
distal end 56. In FIG. 2, the variable perforation pattern 52 is
provided by decreasing density of perforations from inlet end 54
toward distal end 56, for example as shown at high density
perforation area 58, and low density perforation area 60.
[0012] In FIG. 3, flow distributor 62 is shown in elevation and is
a perforated member having a variable perforation pattern 64. Flow
distributor 62 has an inlet end 66 receiving exhaust flowing
laterally thereinto along the noted lateral direction 34, and has a
distal end 68 laterally distally oppositely spaced from inlet end
66. Variable perforation pattern 64 provides a diffuser outlet flow
area which decreases as exhaust flows from inlet end 66 toward
distal end 68. In FIG. 3, variable perforation pattern 64 is
provided by decreasing size of perforations from inlet end 66
toward distal end 68, for example as shown at larger size
perforations 70, and smaller size perforations 72. Perforated
diffuser tubes 50, 62 have variable perforation patterns 52, 64
providing a diffuser outlet flow area which decreases as exhaust
flows laterally away from inlet 16.
[0013] The system provides a method for optimizing exhaust flow
distribution to an aftertreatment element such as 18 in a side
inlet configuration by providing a conically shaped diffuser tube
36 pointing downstream laterally away from inlet 16 and providing
the diffuser tube with a perforated sidewall 46 which conically
convergingly tapers as it extends laterally away from inlet 16, the
method further comprising optimizing even exhaust flow distribution
by adjusting the cone angle of the conically shaped diffuser tube
36 to optimize and achieve even flow distribution of exhaust
flowing axially along axial direction 32 to aftertreatment element
18.
[0014] The system further provides a method for optimizing exhaust
flow distribution to an aftertreatment element such as 18 in a side
inlet configuration by providing a diffuser tube 50, 62 extending
downstream laterally away from inlet 16, providing the diffuser
tube 50, 62 with a variable perforation pattern 52, 64 providing a
diffuser outlet flow area which decreases as exhaust flows
laterally away from inlet 16, the method further comprising
optimizing even exhaust flow distribution by decreasing at least
one of density 58, 60 and size 70, 72 of perforations of the
variable perforation pattern 52, 64 as the diffuser tube 50, 62
extends laterally away from inlet 16, to optimize and achieve even
flow distribution of exhaust flowing axially along axial direction
32 to aftertreatment element 18.
[0015] In the foregoing description, certain terms have been used
for brevity, clearness, and understanding. No unnecessary
limitations are to be implied therefrom beyond the requirement of
the prior art because such terms are used for descriptive purposes
and are intended to be broadly construed. The different
configurations, systems, and method steps described herein may be
used alone or in combination with other configurations, systems,
and method steps. It is to be expected that various equivalents,
alternatives and modifications are possible within the scope of the
appended claims.
* * * * *