U.S. patent application number 14/286284 was filed with the patent office on 2015-11-26 for exhaust aftertreatment system with low-temperature scr.
This patent application is currently assigned to Tenneco Automotive Operating Company Inc.. The applicant listed for this patent is Tenneco Automotive Operating Company Inc.. Invention is credited to Padmanabha Reddy Ettireddy, Michael Golin, Adam J. Kotrba.
Application Number | 20150337702 14/286284 |
Document ID | / |
Family ID | 54554809 |
Filed Date | 2015-11-26 |
United States Patent
Application |
20150337702 |
Kind Code |
A1 |
Ettireddy; Padmanabha Reddy ;
et al. |
November 26, 2015 |
EXHAUST AFTERTREATMENT SYSTEM WITH LOW-TEMPERATURE SCR
Abstract
An aftertreatment system may treat exhaust gas discharged from
an engine. The system may include first and second
selective-catalytic-reduction (SCR) catalysts and a valve. The
valve may be disposed upstream of the first SCR catalyst and at
least one of an oxidation catalyst and a particulate filter. The
valve is connected to first and second exhaust flow paths and is
movable between a first position allowing exhaust gas to flow
through the first flow path and bypass the second flow path and a
second position allowing exhaust gas to flow through the second
flow path and bypass the first flow path. The second SCR catalyst
may be a low-temperature SCR catalyst and may be disposed in the
second flow path. A control module may cause the valve to move
between the first and second positions based on a temperature of
the exhaust gas and/or a temperature of the engine.
Inventors: |
Ettireddy; Padmanabha Reddy;
(Canton, MI) ; Kotrba; Adam J.; (Laingsburg,
MI) ; Golin; Michael; (Dexter, MI) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Tenneco Automotive Operating Company Inc. |
Lake Forest |
IL |
US |
|
|
Assignee: |
Tenneco Automotive Operating
Company Inc.
Lake Forest
IL
|
Family ID: |
54554809 |
Appl. No.: |
14/286284 |
Filed: |
May 23, 2014 |
Current U.S.
Class: |
60/297 |
Current CPC
Class: |
B01D 2251/2067 20130101;
B01D 2255/20746 20130101; F01N 3/2053 20130101; B01D 2255/40
20130101; F01N 3/035 20130101; F02B 37/00 20130101; Y02T 10/24
20130101; B01D 2255/2065 20130101; B01D 2255/20723 20130101; B01D
2255/2073 20130101; F01N 3/2066 20130101; B01D 2251/2062 20130101;
B01D 53/9495 20130101; B01D 2255/20761 20130101; B01D 53/9418
20130101; Y02T 10/144 20130101; B01D 2255/30 20130101; B01D
2255/20738 20130101; B01D 2255/50 20130101; F01N 13/009 20140601;
Y02T 10/12 20130101; B01D 2255/20707 20130101; F01N 3/106 20130101;
B01D 2258/012 20130101; B01D 53/9477 20130101 |
International
Class: |
F01N 3/035 20060101
F01N003/035 |
Claims
1. An aftertreatment system for treating exhaust gas discharged
from a combustion engine, the aftertreatment system comprising: at
least one of an oxidation catalyst and a particulate filter
configured to receive exhaust gas; first and second
selective-catalytic-reduction catalysts; a valve disposed upstream
of the first selective-catalytic-reduction catalyst and the at
least one of the oxidation catalyst and particulate filter, the
valve connected to first and second exhaust flow paths and movable
between a first position allowing exhaust gas to flow through the
first exhaust flow path and bypass the second exhaust flow path and
a second position allowing exhaust gas to flow through the second
exhaust flow path and bypass the first exhaust flow path, the
second selective-catalytic-reduction catalyst is a low-temperature
selective-catalytic-reduction catalyst and is disposed in the
second exhaust flow path; and a control module in communication
with the valve and configured to cause the valve to move between
the first and second positions based on an operating parameter of
the combustion engine.
2. The aftertreatment system of claim 1, wherein the first and
second exhaust flow paths are disposed upstream of the at least one
of the oxidation catalyst and particulate filter.
3. The aftertreatment system of claim 2, wherein the first and
second exhaust flow paths are disposed upstream of the first
selective-catalytic-reduction catalyst.
4. The aftertreatment system of claim 1, wherein the second exhaust
flow path includes a fluid injection port disposed upstream of the
second selective-catalytic-reduction catalyst.
5. The aftertreatment system of claim 4, further comprising another
fluid injection port disposed between the first
selective-catalytic-reduction catalyst and the at least one of the
oxidation catalyst and the particulate filter.
6. The aftertreatment system of claim 1, wherein the at least one
of the oxidation catalyst and particulate filter is disposed in the
first exhaust flow path.
7. The aftertreatment system of claim 6, wherein the first
selective-catalytic-reduction catalyst is disposed in the first
exhaust flow path.
8. An aftertreatment system for treating exhaust gas discharged
from a combustion engine, the aftertreatment system comprising: a
first injection port through which reagent is injected into an
exhaust stream; a first selective-catalytic-reduction catalyst
disposed downstream of the first injection port, the first
selective-catalytic-reduction catalyst is a low-temperature
selective-catalytic-reduction catalyst; at least one of an
oxidation catalyst and a particulate filter disposed downstream of
the low-temperature selective-catalytic-reduction catalyst; a
second injection port through which reagent is injected into the
exhaust stream downstream of the at least one of the oxidation
catalyst and particulate filter; and a second
selective-catalytic-reduction catalyst disposed downstream of the
second injection port.
9. The aftertreatment system of claim 8, further comprising: a
low-temperature flow path including the first
selective-catalytic-reduction catalyst; a bypass flow path isolated
from the first selective-catalytic-reduction catalyst; and a valve
disposed upstream of the second selective-catalytic-reduction
catalyst and movable between a first position allowing exhaust gas
to flow through the low-temperature flow path and preventing
exhaust gas from flowing through the bypass flow path and a second
position allowing exhaust gas to flow through the bypass flow path
and preventing exhaust gas from flowing through the low-temperature
flow path.
10. The aftertreatment system of claim 9, wherein the first
injection port provides reagent to the low-temperature flow
path.
11. The aftertreatment system of claim 10, wherein the
low-temperature flow path and the bypass flow path are disposed
upstream of the at least one of the oxidation catalyst and
particulate filter.
12. The aftertreatment system of claim 9, further comprising a
control module in communication with the valve and configured to
cause the valve to move between the first and second positions
based on an operating parameter of the combustion engine.
13. The aftertreatment system of claim 9, wherein the bypass flow
path includes the second selective-catalytic-reduction
catalyst.
14. The aftertreatment system of claim 13, wherein the bypass flow
path includes the second injection port.
15. An aftertreatment system for treating exhaust gas discharged
from a combustion engine, the aftertreatment system comprising: a
low-temperature flow path including a first
selective-catalytic-reduction catalyst; a bypass flow path
including a second selective-catalytic-reduction catalyst, the
bypass flow path isolated from the first
selective-catalytic-reduction catalyst; and a valve configured to
receive exhaust gas from the combustion engine and movable between
a first position allowing exhaust gas to flow through the
low-temperature flow path and preventing exhaust gas from flowing
through the bypass flow path and a second position allowing exhaust
gas to flow through the bypass flow path and preventing exhaust gas
from flowing through the low-temperature flow path.
16. The aftertreatment system of claim 15, further comprising a
control module in communication with the valve and configured to
cause the valve to move between the first and second positions
based on an operating parameter of the combustion engine.
17. The aftertreatment system of claim 15, further comprising an
oxidation catalyst and a particulate filter disposed upstream of
the second selective-catalytic-reduction catalyst.
18. The aftertreatment system of claim 17, wherein the oxidation
catalyst and the particulate filter are disposed upstream of the
valve.
19. The aftertreatment system of claim 18, further comprising
another valve disposed upstream of the oxidation catalyst and the
particulate filter and movable between a first position allowing
exhaust gas to flow through the oxidation catalyst and the
particulate filter and a second position allowing exhaust gas to
flow through another flow path that is isolated from the oxidation
catalyst and the particulate filter.
20. The aftertreatment system of claim 15, further comprising an
ammonia gas generator disposed upstream of at least one of the
first and second selective-catalytic-reduction catalysts.
21. An aftertreatment system for treating exhaust gas discharged
from a combustion engine, the aftertreatment system comprising: a
first selective-catalytic-reduction catalyst; a second
selective-catalytic-reduction catalyst in fluid communication with
the first selective-catalytic-reduction catalyst; a control valve
in communication with the first and second
selective-catalytic-reduction catalysts and movable between a first
position causing exhaust gas to flow through the first
selective-catalytic-reduction catalyst before flowing through the
second selective-catalytic-reduction catalyst and a second position
causing exhaust gas to flow through the second
selective-catalytic-reduction catalyst before flowing through the
first selective-catalytic-reduction catalyst.
22. The aftertreatment system of claim 21, further comprising a
control module in communication with the valve and configured to
cause the control valve to move between the first and second
positions based on an operating parameter of the combustion
engine.
23. The aftertreatment system of claim 21, further comprising an
oxidation catalyst disposed upstream of the control valve.
24. The aftertreatment system of claim 21, further comprising a
particulate filter disposed upstream of the control valve.
25. The aftertreatment system of claim 21, further comprising a
downstream valve configured to receive exhaust gas after the
exhaust gas has flowed through the first and second
selective-catalytic-reduction catalysts.
26. The aftertreatment system of claim 25, wherein the downstream
valve is movable between a first position allowing exhaust gas from
the second selective-catalytic-reduction catalyst to flow through
the downstream valve and preventing exhaust gas from flowing from
the downstream valve to the first selective-catalytic-reduction
catalyst and a second position allowing exhaust gas from the first
selective-catalytic-reduction catalyst to flow through the
downstream valve and preventing exhaust gas from flowing from the
downstream valve to the second selective-catalytic-reduction
catalyst.
27. The aftertreatment system of claim 26, further comprising a
control module that moves the downstream valve into its first
position and the control valve into its first position
substantially simultaneously and moves the downstream valve into
its second position and the control valve into its second position
substantially simultaneously.
28. The aftertreatment system of claim 21, further comprising an
ammonia gas generator disposed upstream of at least one of the
first and second selective-catalytic-reduction catalysts.
29. An aftertreatment system for treating exhaust gas discharged
from a combustion engine, the aftertreatment system comprising: a
first exhaust gas flow path receiving a first portion of the
exhaust gas from the combustion engine, the first exhaust gas flow
path including an ammonia generator and an injection port through
which a reagent is injected into the exhaust gas; a second exhaust
gas flow path receiving a second portion of the exhaust gas from
the combustion engine and including at least one of a oxidation
catalyst and a particulate filter; a first
selective-catalytic-reduction catalyst receiving exhaust gas from
the first and second exhaust gas flow paths; and a second
selective-catalytic-reduction catalyst receiving exhaust gas from
the first and second exhaust gas flow paths, the second
selective-catalytic-reduction catalyst is a low-temperature
selective-catalytic-reduction catalyst.
30. The aftertreatment system of claim 29, wherein the second
selective-catalytic-reduction catalyst is disposed downstream of
the first selective-catalytic-reduction catalyst.
31. The aftertreatment system of claim 29, wherein the first
exhaust gas flow path includes an inlet disposed downstream of a
turbocharger.
32. The aftertreatment system of claim 29, wherein the first
exhaust gas flow path includes an inlet disposed upstream of a
turbocharger.
33. The aftertreatment system of claim 29, wherein the injection
port is disposed downstream of the ammonia generator.
34. The aftertreatment system of claim 1, wherein the operating
parameter is selected from the group consisting of: a temperature
of the exhaust gas, a temperature of the combustion engine, a
coolant temperature, and a runtime of the combustion engine.
35. The aftertreatment system of claim 12, wherein the operating
parameter is selected from the group consisting of: a temperature
of the exhaust gas, a temperature of the combustion engine, a
coolant temperature, and a runtime of the combustion engine.
36. The aftertreatment system of claim 16, wherein the operating
parameter is selected from the group consisting of: a temperature
of the exhaust gas, a temperature of the combustion engine, a
coolant temperature, and a runtime of the combustion engine.
37. The aftertreatment system of claim 22, wherein the operating
parameter is selected from the group consisting of: a temperature
of the exhaust gas, a temperature of the combustion engine, a
coolant temperature, and a runtime of the combustion engine.
Description
FIELD
[0001] The present disclosure relates to an exhaust aftertreatment
system for a combustion engine.
BACKGROUND
[0002] This section provides background information related to the
present disclosure and is not necessarily prior art.
[0003] In an attempt to reduce the quantity of NO.sub.x and
particulate matter emitted to the atmosphere during internal
combustion engine operation, a number of exhaust aftertreatment
devices have been developed. A need for exhaust aftertreatment
systems particularly arises when diesel combustion processes are
implemented. Typical aftertreatment systems for diesel engine
exhaust may include one or more of a diesel particulate filter
(DPF), a selective catalytic reduction (SCR) system (including a
urea injector), a hydrocarbon (HC) injector, and a diesel oxidation
catalyst (DOC).
[0004] Following a cold start of an engine, exhaust gas
temperatures are much lower than exhaust gas temperatures produced
by the engine at normal operating temperatures. For example,
cold-start exhaust gas temperatures can be between approximately
60-250 degrees Celsius. Conventional SCR catalysts often fail to
effectively reduce NO.sub.x from such cold-start exhaust gas
streams. Therefore, it may be desirable to provide an
aftertreatment system with an SCR catalyst that can effectively
reduce NO.sub.x from cold-start exhaust gas and another SCR
catalyst that can effectively reduce NO.sub.x from exhaust gas at
normal operating temperatures.
SUMMARY
[0005] This section provides a general summary of the disclosure,
and is not a comprehensive disclosure of its full scope or all of
its features.
[0006] In one form, the present disclosure provides an
aftertreatment system for treating exhaust gas discharged from a
combustion engine. The aftertreatment system may include first and
second selective-catalytic-reduction catalysts, a valve and a
control module. The valve may be disposed upstream of the first
selective-catalytic-reduction catalyst and at least one of an
oxidation catalyst and a particulate filter. The valve may be
connected to first and second exhaust flow paths and may be movable
between a first position allowing exhaust gas to flow through the
first exhaust flow path and bypass the second exhaust flow path and
a second position allowing exhaust gas to flow through the second
exhaust flow path and bypass the first exhaust flow path. The
second selective-catalytic-reduction catalyst may be a
low-temperature selective-catalytic-reduction catalyst and may be
disposed in the second exhaust flow path. The control module is in
communication with the valve and may be configured to cause the
valve to move between the first and second positions based on at
least one of a temperature of the exhaust gas and a temperature of
the combustion engine.
[0007] In some embodiments, the first and second exhaust flow paths
are disposed upstream of the at least one of the at least one of
the oxidation catalyst and particulate filter.
[0008] In some embodiments, the first and second exhaust flow paths
are disposed upstream of the first selective-catalytic-reduction
catalyst.
[0009] In some embodiments, the second exhaust flow path includes a
fluid injection port (e.g., a port through which urea, ammonia or
any other reagent can be injected into the exhaust stream) disposed
upstream of the second selective-catalytic-reduction catalyst.
[0010] In some embodiments, the aftertreatment system includes
another fluid injection port disposed between the first
selective-catalytic-reduction catalyst and the at least one of the
oxidation catalyst and the particulate filter.
[0011] In some embodiments, the at least one of the oxidation
catalyst and particulate filter is disposed in the first exhaust
flow path.
[0012] In some embodiments, the aftertreatment system includes an
oxidation catalyst and a particulate filter disposed directly
adjacent and/or proximate to each other.
[0013] In some embodiments, the first selective-catalytic-reduction
catalyst is disposed in the first exhaust flow path.
[0014] In some embodiments, the aftertreatment system includes an
ammonia gas generator disposed upstream of at least one of the
first and second selective-catalytic-reduction catalysts.
[0015] In another form, the present disclosure provides an
aftertreatment system that may include first and second injection
ports, first and second selective-catalytic-reduction catalysts,
and at least one of an oxidation catalyst and a particulate filter.
Reagent may be injected into the exhaust stream through the first
injection port. The first selective-catalytic-reduction catalyst
may be disposed downstream of the first injection port. The first
selective-catalytic-reduction catalyst may be a low-temperature
selective-catalytic-reduction catalyst. The oxidation catalyst
and/or particulate filter may be disposed downstream of the
low-temperature selective-catalytic-reduction catalyst. Reagent may
be injected into the exhaust stream through the second injection
port downstream of the oxidation catalyst and/or the particulate
filter. The second selective-catalytic-reduction catalyst may be
disposed downstream of the second injection port.
[0016] The first and second injection ports can be or include a DEF
dosing system or urea or ammonia injector, nozzle or other orifice
through which reagent can be injected into the exhaust stream.
[0017] In some embodiments, the aftertreatment system may include a
low-temperature flow path, a bypass flow path, and a valve. The
low-temperature flow path may include the first
selective-catalytic-reduction catalyst. The bypass flow path may be
isolated from the first selective-catalytic-reduction catalyst. The
valve may be disposed upstream of the second
selective-catalytic-reduction catalyst and may be movable between a
first position allowing exhaust gas to flow through the
low-temperature flow path and preventing exhaust gas from flowing
through the bypass flow path and a second position allowing exhaust
gas to flow through the bypass flow path and preventing exhaust gas
from flowing through the low-temperature flow path.
[0018] In some embodiments, reagent is injected into the
low-temperature flow path through the first injection port.
[0019] In some embodiments, the low-temperature flow path and the
bypass flow path are disposed upstream of the at least one of the
oxidation catalyst and particulate filter.
[0020] In some embodiments, the aftertreatment system includes a
control module in communication with the valve and configured to
cause the valve to move between the first and second positions
based on at least one of a temperature of the exhaust gas and a
temperature of the combustion engine.
[0021] In some embodiments, the bypass flow path includes the
second selective-catalytic-reduction catalyst.
[0022] In some embodiments, the bypass flow path includes the
second injection port.
[0023] In some embodiments, the aftertreatment system includes an
ammonia gas generator disposed upstream of at least one of the
first and second selective-catalytic-reduction catalysts.
[0024] In another form, the present disclosure provides an
aftertreatment system that may include a low-temperature flow path,
a bypass flow path and a valve. The low-temperature flow path may
include a first selective-catalytic-reduction catalyst. The bypass
flow path may include a second selective-catalytic-reduction
catalyst. The bypass flow path may be isolated from the first
selective-catalytic-reduction catalyst. The valve may be configured
to receive exhaust gas from the combustion engine. The valve may be
movable between a first position allowing exhaust gas to flow
through the low-temperature flow path and preventing exhaust gas
from flowing through the bypass flow path and a second position
allowing exhaust gas to flow through the bypass flow path and
preventing exhaust gas from flowing through the low-temperature
flow path.
[0025] In some embodiments, the aftertreatment system includes a
control module in communication with the valve and configured to
cause the valve to move between the first and second positions
based on at least one of a temperature of the exhaust gas and a
temperature of the combustion engine.
[0026] In some embodiments, the aftertreatment system may include
an oxidation catalyst and a particulate filter disposed upstream of
the second selective-catalytic-reduction catalyst.
[0027] In some embodiments, the oxidation catalyst and the
particulate filter are disposed upstream of the valve.
[0028] In some embodiments, the aftertreatment system includes
another valve disposed upstream of the oxidation catalyst and the
particulate filter and movable between a first position allowing
exhaust gas to flow through the oxidation catalyst and the
particulate filter and a second position allowing exhaust gas to
flow through another flow path that is isolated from the oxidation
catalyst and the particulate filter.
[0029] In some embodiments, the aftertreatment system includes an
ammonia gas generator disposed upstream of at least one of the
first and second selective-catalytic-reduction catalysts.
[0030] In another form, the present disclosure provides an
aftertreatment system that may include first and second
selective-catalytic-reduction catalysts and a control valve. The
second selective-catalytic-reduction catalyst may be in fluid
communication with the first selective-catalytic-reduction
catalyst. The control valve may be in communication with the first
and second selective-catalytic-reduction catalysts. The control
valve may be movable between a first position causing exhaust gas
to flow through the first selective-catalytic-reduction catalyst
before flowing through the second selective-catalytic-reduction
catalyst and a second position causing exhaust gas to flow through
the second selective-catalytic-reduction catalyst before flowing
through the first selective-catalytic-reduction catalyst.
[0031] In some embodiments, the aftertreatment system includes a
control module in communication with the valve. The control module
may be configured to cause the control valve to move between the
first and second positions based on at least one of a temperature
of the exhaust gas and a temperature of the combustion engine.
[0032] In some embodiments, the aftertreatment system includes an
oxidation catalyst disposed upstream of the control valve.
[0033] In some embodiments, the aftertreatment system includes a
particulate filter disposed upstream of the control valve.
[0034] In some embodiments, the aftertreatment system includes a
downstream valve configured to receive exhaust gas after the
exhaust gas has flowed through the first and second
selective-catalytic-reduction catalysts.
[0035] In some embodiments, the downstream valve is movable between
a first position allowing exhaust gas from the second
selective-catalytic-reduction catalyst to flow through the
downstream valve and preventing exhaust gas from flowing from the
downstream valve to the first selective-catalytic-reduction
catalyst and a second position allowing exhaust gas from the first
selective-catalytic-reduction catalyst to flow through the
downstream valve and preventing exhaust gas from flowing from the
downstream valve to the second selective-catalytic-reduction
catalyst.
[0036] In some embodiments, the aftertreatment system includes a
control module that moves the downstream valve into its first
position and the control valve into its first position
substantially simultaneously. The control module may also move the
downstream valve into its second position and the control valve
into its second position substantially simultaneously.
[0037] In some embodiments, the aftertreatment system includes an
ammonia gas generator disposed upstream of at least one of the
first and second selective-catalytic-reduction catalysts.
[0038] In another form, the present disclosure provides an
aftertreatment system for treating exhaust gas discharged from a
combustion engine. The aftertreatment system may include first and
second exhaust gas flow paths and first and second
selective-catalytic-reduction catalysts. The first exhaust gas flow
path may receive a first portion of the exhaust gas from the
combustion engine. The first exhaust gas flow path may include an
ammonia generator and an injection port through which a reagent is
injected into the exhaust gas. The second exhaust gas flow path may
receive a second portion of the exhaust gas from the combustion
engine and may include at least one of a oxidation catalyst and a
particulate filter. The first and second exhaust gas flow paths may
be fluidly isolated from each other. The first
selective-catalytic-reduction catalyst may receive exhaust gas from
the first and second exhaust gas flow paths. The second
selective-catalytic-reduction catalyst may receive exhaust gas from
the first and second exhaust gas flow paths. The second
selective-catalytic-reduction catalyst may be a low-temperature
selective-catalytic-reduction catalyst.
[0039] In some embodiments, the second
selective-catalytic-reduction catalyst is disposed downstream of
the first selective-catalytic-reduction catalyst.
[0040] In some embodiments, the second
selective-catalytic-reduction catalyst is disposed upstream of the
first selective-catalytic-reduction catalyst.
[0041] In some embodiments, the first exhaust gas flow path
includes an inlet disposed downstream of a turbocharger.
[0042] In some embodiments, the first exhaust gas flow path
includes an inlet disposed upstream of a turbocharger.
[0043] In some embodiments, the injection port is disposed
downstream of the ammonia generator.
[0044] Further areas of applicability will become apparent from the
description provided herein. The description and specific examples
in this summary are intended for purposes of illustration only and
are not intended to limit the scope of the present disclosure.
DRAWINGS
[0045] The drawings described herein are for illustrative purposes
only of selected embodiments and not all possible implementations,
and are not intended to limit the scope of the present
disclosure.
[0046] FIG. 1 is a schematic representation of an engine and
aftertreatment system according to the principles of the present
disclosure;
[0047] FIG. 2 is a schematic representation of another
aftertreatment system according to the principles of the present
disclosure;
[0048] FIG. 3 is a schematic representation of yet another
aftertreatment system according to the principles of the present
disclosure;
[0049] FIG. 4 is a schematic representation of yet another
aftertreatment system according to the principles of the present
disclosure;
[0050] FIG. 5 is a schematic representation of yet another
aftertreatment system according to the principles of the present
disclosure; and
[0051] FIG. 6 is a schematic representation of yet another
aftertreatment system according to the principles of the present
disclosure.
[0052] Corresponding reference numerals indicate corresponding
parts throughout the several views of the drawings.
DETAILED DESCRIPTION
[0053] Example embodiments will now be described more fully with
reference to the accompanying drawings.
[0054] Example embodiments are provided so that this disclosure
will be thorough, and will fully convey the scope to those who are
skilled in the art. Numerous specific details are set forth such as
examples of specific components, devices, and methods, to provide a
thorough understanding of embodiments of the present disclosure. It
will be apparent to those skilled in the art that specific details
need not be employed, that example embodiments may be embodied in
many different forms and that neither should be construed to limit
the scope of the disclosure. In some example embodiments,
well-known processes, well-known device structures, and well-known
technologies are not described in detail.
[0055] The terminology used herein is for the purpose of describing
particular example embodiments only and is not intended to be
limiting. As used herein, the singular forms "a," "an," and "the"
may be intended to include the plural forms as well, unless the
context clearly indicates otherwise. The terms "comprises,"
"comprising," "including," and "having," are inclusive and
therefore specify the presence of stated features, integers, steps,
operations, elements, and/or components, but do not preclude the
presence or addition of one or more other features, integers,
steps, operations, elements, components, and/or groups thereof. The
method steps, processes, and operations described herein are not to
be construed as necessarily requiring their performance in the
particular order discussed or illustrated, unless specifically
identified as an order of performance. It is also to be understood
that additional or alternative steps may be employed.
[0056] When an element or layer is referred to as being "on,"
"engaged to," "connected to," or "coupled to" another element or
layer, it may be directly on, engaged, connected or coupled to the
other element or layer, or intervening elements or layers may be
present. In contrast, when an element is referred to as being
"directly on," "directly engaged to," "directly connected to," or
"directly coupled to" another element or layer, there may be no
intervening elements or layers present. Other words used to
describe the relationship between elements should be interpreted in
a like fashion (e.g., "between" versus "directly between,"
"adjacent" versus "directly adjacent," etc.). As used herein, the
term "and/or" includes any and all combinations of one or more of
the associated listed items.
[0057] Although the terms first, second, third, etc. may be used
herein to describe various elements, components, regions, layers
and/or sections, these elements, components, regions, layers and/or
sections should not be limited by these terms. These terms may be
only used to distinguish one element, component, region, layer or
section from another region, layer or section. Terms such as
"first," "second," and other numerical terms when used herein do
not imply a sequence or order unless clearly indicated by the
context. Thus, a first element, component, region, layer or section
discussed below could be termed a second element, component,
region, layer or section without departing from the teachings of
the example embodiments.
[0058] Spatially relative terms, such as "inner," "outer,"
"beneath," "below," "lower," "above," "upper," and the like, may be
used herein for ease of description to describe one element or
feature's relationship to another element(s) or feature(s) as
illustrated in the figures. Spatially relative terms may be
intended to encompass different orientations of the device in use
or operation in addition to the orientation depicted in the
figures. For example, if the device in the figures is turned over,
elements described as "below" or "beneath" other elements or
features would then be oriented "above" the other elements or
features. Thus, the example term "below" can encompass both an
orientation of above and below. The device may be otherwise
oriented (rotated 90 degrees or at other orientations) and the
spatially relative descriptors used herein interpreted
accordingly.
[0059] FIG. 1 depicts an exhaust gas aftertreatment system 10 for
treating the exhaust output from an exemplary engine 12 to an
exhaust passageway 14. A turbocharger 16 includes a driven member
(not shown) positioned in an exhaust stream. During engine
operation, the exhaust stream causes the driven member to rotate
and provide compressed air to an intake passage (not shown) of the
engine 12. It will be appreciated that the exhaust gas
aftertreatment system 10 can also be used to treat exhaust output
from a naturally aspirated engine or any other engine that does not
include a turbocharger.
[0060] The exhaust aftertreatment system 10 may include a control
valve 18, a bypass flow path 20, a low-temperature-treatment flow
path 22, a first injector or injection port 24 (e.g., a diesel
exhaust fluid (DEF) dosing system or urea or ammonia injector,
nozzle or other orifice through which reagent can be injected into
the exhaust stream), a first selective-catalytic-reduction (SCR)
catalyst 26, a diesel oxidation catalyst (DOC) 28, a diesel
particulate filter (DPF) 30, a second injector or injection port 32
(e.g., a DEF dosing system or urea or ammonia injector, nozzle or
other orifice through which reagent can be injected into the
exhaust stream), and a second SCR catalyst 34. The
low-temperature-treatment flow path 22 may include the first
injector 24 and the first SCR catalyst 26. The first injector 24
may inject a gaseous ammonia, for example, or any other reagent
into the exhaust stream upstream of the first SCR catalyst 26. The
first injector 24 may be disposed directly or indirectly adjacent
and/or proximate to the first SCR catalyst 26.
[0061] The first SCR catalyst 26 may be a low-temperature SCR
catalyst configured to effectively reduce NO.sub.x from
low-temperature exhaust gas (e.g., exhaust gas at 60-150 degrees
Celsius or 60-250 degrees Celsius) that may be discharged from the
engine 12 for a period of time following a cold start of the engine
12. For example, the first SCR catalyst 26 may include a metal
oxide supported on titanium oxide (MO.sub.x/TiO.sub.2), a metal
oxide supported on a titania-silica (TiO.sub.2/SiO.sub.2) mixed
oxide support, or a metal oxide supported on a beta zeolite. Metals
used for such catalysts could include ammonium metavenadate (V),
manganese (Mn), iron (Fe), cobalt (Co), copper (Cu) or cerium (Ce),
for example. The metals may be loaded onto the TiO.sub.2 support or
the TiO.sub.2/SiO.sub.2 support by a wet-impregnation method, for
example. The metals may be loaded onto the beta zeolite by a cation
exchange method, for example. It will be appreciated that any
suitable low-temperature SCR catalyst capable of effectively
treating low-temperature exhaust gas could be employed.
[0062] Exhaust flowing through the bypass flow path 20 bypasses the
first injector 24 and the first SCR catalyst 26. The control valve
18 may receive exhaust gas from the engine 12 and turbocharger 16
and may be movable between first and second positions. In the first
position, the control valve 18 allows exhaust gas to flow through
the low-temperature-treatment flow path 22 and restricts or
prevents exhaust gas from flowing through the bypass flow path 20.
In the second position, the control valve 18 allows exhaust gas to
flow through the bypass flow path 20 and prevents exhaust gas from
flowing through the low-temperature-treatment flow path 22. In some
configurations, the control valve 18 may be movable to one or more
intermediate positions between the first and second positions to
allow a portion of the exhaust gas to flow through the bypass flow
path 20 and another portion of the exhaust gas to flow through the
low-temperature treatment flow path 22.
[0063] A control module 36 may control movement of the control
valve 18 based on a temperature of the exhaust gas discharged from
the engine 12 (measured by a temperature sensor in the exhaust
stream), a temperature of engine coolant (measured by an engine
coolant temperature sensor) and/or a runtime of the engine 12, for
example. The control module 36 may cause the control valve 18 to
move into the first position when the exhaust temperature or
coolant temperature is below a predetermined value (between about
150 or 250 degrees Celsius, for example). The control module 36 may
cause the control valve 18 to move into the second position once
the exhaust temperature or coolant temperature rises above the
predetermined value.
[0064] The control module 36 may include or be part of an
Application Specific Integrated Circuit (ASIC); a digital, analog,
or mixed analog/digital discrete circuit; a digital, analog, or
mixed analog/digital integrated circuit; a combinational logic
circuit; a field programmable gate array (FPGA); a processor
(shared, dedicated, or group) that executes code; memory (shared,
dedicated, or group) that stores code executed by a processor;
other suitable hardware components that provide the described
functionality; or a combination of some or all of the above, such
as in a system-on-chip. The control module 36 may be a part of or
include a control unit controlling one or more other vehicle
systems. Alternatively, the control module 36 may be a control unit
dedicated to the exhaust aftertreatment system 10. The control
module 36 may be in communication with and control operation of the
control valve 18, the injectors 24, 32 and/or other aftertreatment
components.
[0065] The DOC 28, the DPF 30, the second injector 32 and the
second SCR catalyst 34 may be disposed downstream of the bypass
flow path 20 and the low-temperature-treatment flow path 22. The
DPF 30 may be disposed downstream of the DOC 28. The DPF 30 may be
disposed directly or indirectly adjacent and/or proximate to the
DOC 28. The second injector 32 may be disposed downstream of the
DPF 30 and upstream of the second SCR catalyst 34. The second
injector 32 may be disposed directly or indirectly adjacent and/or
proximate to the second SCR catalyst 34. The second SCR catalyst 34
may be a normal-to-high-temperature SCR catalyst configured to
effectively reduce NO.sub.x from normal-to-high-temperature exhaust
gas (e.g., exhaust approximately equal to or greater than about 150
degrees Celsius, or approximately equal to or greater than about
250 degrees Celsius) that may be discharged from the engine 12
under normal and/or high-load operating conditions.
[0066] With reference to FIG. 2, another aftertreatment system 110
is provided that may treat the exhaust gas discharged from the
engine 12. The aftertreatment system 110 may include a DOC 128, a
DPF 130, an injector or injection port 124, a control valve 118, a
low-temperature SCR catalyst 132, a normal-to-high-temperature SCR
catalyst 134, and a control module 136. The structure and function
of the DOC 128, DPF 130, injector 124, SCR catalysts 132, 134, and
control module 136 may be similar or identical to that of the DOC
28, DPF 30, injector 24,32, SCR catalysts 26, 34, and control
module 36, respectively, apart from any exceptions described below
and/or shown in the figures. Therefore, similar features will not
be described again in detail.
[0067] The DOC 128 may receive exhaust gas from the engine 12 and
turbocharger 16. The DPF 130 may be disposed downstream of the DOC
128. The injector 124 may inject ammonia (or another reagent) into
the exhaust stream downstream of the DPF 130 and upstream of the
control valve 118. The control valve 118 may be fluidly coupled to
the low-temperature SCR catalyst 132 and the
normal-to-high-temperature SCR catalyst 134. The low-temperature
SCR catalyst 132 and the normal-to-high-temperature SCR catalyst
134 may be fluidly coupled to each other.
[0068] The control module 136 may cause the control valve 118 to
move between first and second positions. In the first position,
fluid received through an inlet 119 of the control valve 118 is
routed along a first flow path 140 (indicated in dashed lines in
FIG. 2) in which the fluid flows from the control valve 118 to the
low-temperature SCR catalyst 132, then to the
normal-to-high-temperature SCR catalyst 134, then back to the
control valve 118. The fluid then exits the control valve 118
through an outlet 121 before being discharged into the ambient
environment. When the control valve 118 is in the second position,
fluid received through the inlet 119 of the control valve 118 is
routed along a second flow path 142 (indicated in solid lines in
FIG. 2) in which the fluid flows from the control valve 118 to the
normal-to-high-temperature SCR catalyst 134, then to the
low-temperature SCR catalyst 132, then back to the control valve
118. The fluid then exits the control valve 118 through the outlet
121 before being discharged into the ambient environment.
[0069] As described above, the control module 136 may control
movement of the control valve 118 based on a temperature of the
exhaust gas discharged from the engine 12, a temperature of engine
coolant and/or a runtime of the engine 12, for example. The control
module 136 may cause the control valve 118 to move into the first
position when the exhaust temperature or coolant temperature is
below a predetermined value (between about 150 or 250 degrees
Celsius, for example). The control module 136 may cause the control
valve 118 to move into the second position once the exhaust
temperature or coolant temperature rises above the predetermined
value.
[0070] With reference to FIG. 3, another aftertreatment system 210
is provided that may treat the exhaust gas discharged from the
engine 12. The aftertreatment system 210 may include a DOC 228, a
DPF 230, an injector or injection port 224, a first control valve
218, a second control valve 220, a low-temperature SCR catalyst
232, a normal-to-high-temperature SCR catalyst 234, and a control
module 236. The structure and function of the DOC 228, DPF 230,
injector 224, SCR catalysts 232, 234, and control module 236 may be
similar or identical to that of the DOC 28, DPF 30, injector 24,32,
SCR catalysts 26, 34, and control module 36, respectively, apart
from any exceptions described below and/or shown in the figures.
Therefore, similar features will not be described again in
detail.
[0071] The DOC 228 may receive exhaust gas from the engine 12 and
turbocharger 16. The DPF 230 may be disposed downstream of the DOC
228. The injector 224 may inject ammonia (or other reagent) into
the exhaust stream downstream of the DPF 230 and upstream of the
first control valve 218. The first control valve 218 may be fluidly
coupled to the low-temperature SCR catalyst 232 and the
normal-to-high-temperature SCR catalyst 234. The low-temperature
SCR catalyst 232 and the normal-to-high-temperature SCR catalyst
234 may be fluidly coupled to each other. The second control valve
220 may be fluidly coupled to the low-temperature SCR catalyst 232
and the normal-to-high-temperature SCR catalyst 234.
[0072] The control module 236 may cause the first and second
control valves 218, 220 to move substantially simultaneously
between first and second positions. When the control valves 218,
220 are in the first position, fluid received through an inlet 219
of the first control valve 218 is routed out of the first control
valve 218 through a first outlet 221 along a first flow path 240
(indicated in dashed lines in FIG. 3) to the low-temperature SCR
catalyst 232. From the low-temperature SCR catalyst 232, the fluid
flows to the normal-to-high-temperature SCR catalyst 234, and then
into a first inlet 223 of the second control valve 220. The fluid
then exits the second control valve 220 through an outlet 225
before being discharged into the ambient environment. When the
control valves 218, 220 are in the second position, fluid received
through the inlet 219 of the first control valve 218 is routed out
of the first control valve 218 through a second outlet 227 along a
second flow path 242 (indicated in solid lines in FIG. 3) to the
normal-to-high-temperature SCR catalyst 234. From the
normal-to-high-temperature SCR catalyst 234, the fluid flows to the
low-temperature SCR catalyst 232, and then into a second inlet 229
of the second control valve 220. The fluid then exits the second
control valve 220 through the outlet 225 before being discharged
into the ambient environment.
[0073] As described above, the control module 236 may control
movement of the valves 218, 220 based on a temperature of the
exhaust gas discharged from the engine 12, a temperature of engine
coolant and/or a runtime of the engine 12, for example. The control
module 236 may cause the valves 218, 220 to move into the first
position when the exhaust temperature or coolant temperature is
below a predetermined value (between about 150 or 250 degrees
Celsius, for example). The control module 236 may cause the valves
218, 220 to move into the second position once the exhaust
temperature or coolant temperature rises above the predetermined
value.
[0074] With reference to FIG. 4, another aftertreatment system 310
is provided that may treat the exhaust gas discharged from the
engine 12. The aftertreatment system 310 may include a first
injector or injection port 324, a low-temperature SCR catalyst 326,
a DOC 328, a DPF 330, a second injector or injection port 332 and a
normal-to-high-temperature SCR catalyst 334. The structure and
function of the injectors 324, 332, the SCR catalysts 326, 334, the
DOC 328 and the DPF 330 may be similar or identical to that of the
injectors 24, 32, the SCR catalysts 26, 34, the DOC 28 and the DPF
30, respectively, apart from any exceptions described below and/or
shown in the figures. Therefore, similar features will not be
described again in detail.
[0075] The first injector 324 may inject ammonia (or any other
reagent) into the exhaust stream downstream of the engine 12 and
turbocharger 16. The low-temperature SCR catalyst 326 may be
disposed downstream of the first injector 324 and may be disposed
directly or indirectly adjacent and/or proximate to the first
injector 324. The DOC 328 may be disposed downstream of the
low-temperature SCR catalyst 326. The DPF 330 may be disposed
downstream of the DOC 328 and may be directly or indirectly
adjacent and/or proximate to the DOC 328. The second injector 332
may be disposed downstream of the DPF 330 and upstream of the
normal-to-high-temperature SCR catalyst 334. The second injector
332 may be directly or indirectly adjacent and/or proximate to the
normal-to-high-temperature SCR catalyst 334.
[0076] With reference to FIG. 5, another aftertreatment system 410
is provided that may treat the exhaust gas discharged from the
engine 12. The aftertreatment system 410 may include a first
control valve 418, a bypass flow path 420, a
low-temperature-treatment flow path 422, and a second control valve
424. A control module 426 may be in communication with and control
operation of the first and second control valves 418, 424. The
structure and function of the control module 426 may be similar or
identical to that of the control module 36 described above, apart
from any exceptions described herein and/or shown in the
figures.
[0077] The bypass flow path 420 may be in fluid communication with
the first and second control valves 418, 424 and may include a DOC
428, a DPF 430, a first injector or injection port 432, and a
normal-to-high-temperature SCR catalyst 434. The DOC 428 and DPF
430 may be disposed between the first and second control valves
418, 424 and may be directly or indirectly adjacent and/or
proximate to each other. The first injector 432 may inject ammonia
(or another reagent) downstream of the DPF 430 and upstream of the
second control valve 424. The normal-to-high-temperature SCR
catalyst 434 may be disposed downstream of the second control valve
424. The structure and function of the DOC 428, the DPF 430, the
first injector 432, and the normal-to-high-temperature SCR catalyst
434 may be similar or identical to that of the DOC 28, the DPF 30,
the second injector 32, and the second SCR catalyst 34,
respectively, apart from any exceptions described herein and/or
shown in the figures.
[0078] The low-temperature-treatment flow path 422 may be in fluid
communication with the first and second control valves 418, 424 and
may include a second injector or injection port 436 and a
low-temperature SCR catalyst 438. The structure and function of the
second injector 436 and the low-temperature SCR catalyst 438 may be
similar or identical to that of the injector 24 and low-temperature
SCR catalyst 26, respectively, apart from any exceptions described
herein and/or shown in the figures. Therefore, similar features
will not be described again in detail. Briefly, the second injector
436 may inject gaseous ammonia, for example, and/or another reagent
into the exhaust stream in the low-temperature-treatment flow path
422 between the first and second control valves 418, 424. The
low-temperature SCR catalyst 438 may be disposed downstream of the
second control valve 424.
[0079] The control module 426 may move the first and second control
valves 418, 424 substantially simultaneously between first and
second positions. When the control valves 418, 424 are in the first
position, fluid received through an inlet 419 of the first control
valve 418 is routed out of the first control valve 418 through a
first outlet 421 and into the low-temperature-treatment flow path
422. As described above, the second injector 436 may inject reagent
into the low-temperature-treatment flow path 422 between the first
and second control valves 424. Then, the exhaust stream may flow
into a first inlet 423 of the second control valve 424 and exit the
second control valve 424 through a first outlet 425. From the first
outlet 425, the exhaust may flow through the low-temperature SCR
catalyst 438 before being discharged to the ambient environment.
The low-temperature-treatment flow path 422 may bypass the DOC 428,
the DPF 430, the first injector 432 and the
normal-to-high-temperature SCR catalyst 434.
[0080] When the control valves 418, 424 are in the second position,
fluid received through the inlet 419 of the first control valve 418
is routed out of the first control valve 418 through a second
outlet 427 and into the bypass flow path 420. From the second
outlet 427, the fluid may flow through the DOC 428 and through the
DPF 430 before reagent is injected into the exhaust stream by the
first injector 432. Thereafter, the exhaust may flow into the
second control valve 424 through a second inlet 429 and out of the
second control valve 424 through a second outlet 431. From the
second outlet 431, the exhaust may flow through the
normal-to-high-temperature SCR catalyst 434 before being discharged
into the ambient environment.
[0081] As described above, the control module 426 may control
movement of the control valves 418, 424 based on a temperature of
the exhaust gas discharged from the engine 12, a temperature of
engine coolant and/or a runtime of the engine 12, for example. The
control module 426 may cause the control valves 418, 424 to move
into the first position when the exhaust temperature or coolant
temperature is below a predetermined value (between about 150 or
250 degrees Celsius, for example). The control module 426 may cause
the control valves 418, 424 to move into the second position once
the exhaust temperature or coolant temperature rises above the
predetermined value.
[0082] In some configurations, the control module 426 may, under
certain conditions, cause the first control valve 418 to be in the
first position while the second control valve 424 is in the second
position. While the control valves 418, 424 are in such positions,
the exhaust gas may flow from the first control valve 418 through
an upstream portion of the low-temperature-treatment flow path 422
(bypassing the DOC 428, the DPF 430 and first injector 432) and out
of the second outlet 431 of the second control valve 424 to the
normal-to-high-temperature SCR catalyst 434 before being discharged
to the ambient environment.
[0083] In some configurations, the control module 426 may, under
certain conditions, cause the first control valve 418 to be in the
second position while the second control valve 424 is in the first
position. While the control valves 418, 424 are in such positions,
the exhaust gas may flow from the first control valve 418 through
the DOC 428 and the DPF 430. From the DPF 430, the exhaust stream
may flow into the second control valve 424 and exit the second
control valve 424 through the first outlet 425. From the first
outlet 425, the exhaust may flow through the low-temperature SCR
catalyst 438 before being discharged to the ambient
environment.
[0084] With reference to FIG. 6, another aftertreatment system 510
is provided that may treat the exhaust gas discharged from the
engine 12. The aftertreatment system 510 may include a first
exhaust gas flow path 512, a second exhaust gas flow path 514, a
normal-to-high-temperature SCR catalyst 516 and a low-temperature
SCR catalyst 518. While FIG. 6 depicts the
normal-to-high-temperature SCR catalyst 516 being upstream of the
low-temperature SCR catalyst 518, in some embodiments,
low-temperature SCR catalyst 518 may be disposed upstream of the
normal-to-high-temperature SCR catalyst 516. The structure and
function of the SCR catalysts 516, 518 may be similar or identical
to that of the SCR catalysts 34, 26, respectively, apart from any
exceptions described below and/or shown in the figures. Therefore,
similar features will not be described again in detail.
[0085] The first exhaust gas flow path 512 may include an ammonia
gas generator 520 and an injector or injection port 522 (e.g., an
injector, nozzle and/or other orifice through which reagent can be
injected into the exhaust stream). FIG. 6 shows an inlet 524 of the
first exhaust gas flow path 512 disposed downstream of the
turbocharger 16. In some embodiments, however, the inlet 526 may be
upstream of the turbocharger 16 so that fluid flowing through the
first exhaust gas flow path 512 bypasses the turbocharger 16. The
ammonia gas generator 520 may receive exhaust gas and convert urea
(or another compound containing ammonia) to gaseous ammonia (or a
gas containing ammonia). An outlet 526 of the first exhaust gas
flow path 512 may be disposed upstream of the SCR catalysts 516,
518 such that the injector 522 may feed the exhaust and gaseous
ammonia to the SCR catalysts 516, 518.
[0086] The second exhaust gas flow path 514 may include a DOC 528
and a DPF 530. The DOC 528 and DPF 530 may be disposed between the
inlet 524 and outlet 526 of the first exhaust gas flow path 512.
The DOC 528 may be upstream or downstream of the DPF 530. The
structure and function of the DOC 528 and DPF 530 may be similar or
identical to that of the DOC 28 and DPF 30 described above.
[0087] It will be appreciated that any of the aftertreatment
systems 10, 110, 210, 310, 410 described above may include an
exhaust flow path similar or identical to the first exhaust gas
flow path 512 (e.g., including the ammonia gas generator 520 and/or
injector or injection port 522) that may bypass the DOC, DPF and/or
one or more other components of the aftertreatment system 10, 110,
210, 310, 410.
[0088] The foregoing description of the embodiments has been
provided for purposes of illustration and description. It is not
intended to be exhaustive or to limit the disclosure. Individual
elements or features of a particular embodiment are generally not
limited to that particular embodiment, but, where applicable, are
interchangeable and can be used in a selected embodiment, even if
not specifically shown or described. The same may also be varied in
many ways. Such variations are not to be regarded as a departure
from the disclosure, and all such modifications are intended to be
included within the scope of the disclosure.
* * * * *