U.S. patent application number 12/777730 was filed with the patent office on 2011-11-17 for apparatus and system for trapping debris and arresting sparks.
This patent application is currently assigned to CUMMINS FILTRATION IP, INC. Invention is credited to Peter Christianson, Keith J. Thompson.
Application Number | 20110277454 12/777730 |
Document ID | / |
Family ID | 44910499 |
Filed Date | 2011-11-17 |
United States Patent
Application |
20110277454 |
Kind Code |
A1 |
Christianson; Peter ; et
al. |
November 17, 2011 |
APPARATUS AND SYSTEM FOR TRAPPING DEBRIS AND ARRESTING SPARKS
Abstract
Described herein are various embodiments of an apparatus and
system for trapping debris and arresting sparks that overcomes at
least some shortcomings of the prior art approaches. According to
one embodiment, an apparatus is disclosed for mitigating failure of
an exhaust after-treatment component in an internal combustion
engine system capable of generating an exhaust gas stream. The
apparatus includes a housing that includes an exhaust inlet,
exhaust outlet, and exhaust flow channel positioned between the
exhaust inlet and outlet. Also, the apparatus includes a
tubular-shaped mesh screen positioned substantially entirely within
the exhaust flow channel. The mesh screen includes a closed end
positioned proximate the exhaust inlet of the housing and an
opposing open end positioned proximate the exhaust outlet of the
housing. The mesh screen is configured to capture failed exhaust
after-treatment component particles within the exhaust gas
stream.
Inventors: |
Christianson; Peter;
(Waunakee, WI) ; Thompson; Keith J.; (Fitchburg,
WI) |
Assignee: |
CUMMINS FILTRATION IP, INC
Minneapolis
MN
|
Family ID: |
44910499 |
Appl. No.: |
12/777730 |
Filed: |
May 11, 2010 |
Current U.S.
Class: |
60/297 ;
60/311 |
Current CPC
Class: |
F01N 3/0821 20130101;
F01N 3/06 20130101; F01N 3/035 20130101; F01N 2230/06 20130101 |
Class at
Publication: |
60/297 ;
60/311 |
International
Class: |
F01N 3/035 20060101
F01N003/035; F01N 3/021 20060101 F01N003/021 |
Claims
1. An apparatus for mitigating failure of an exhaust gas
after-treatment component in an internal combustion engine system
capable of generating an exhaust gas stream, comprising: a housing
comprising an exhaust inlet, an exhaust outlet, and an exhaust flow
channel positioned between the exhaust inlet and outlet; and a
tubular-shaped mesh screen positioned substantially entirely within
the exhaust flow channel, the mesh screen comprising a closed end
positioned proximate the exhaust inlet of the housing and an
opposing open end positioned proximate the exhaust outlet of the
housing, wherein the mesh screen is configured to capture failed
exhaust gas after-treatment component particles within the exhaust
gas stream.
2. The apparatus of claim 1, wherein the mesh screen defines an
interior space having an increasing cross-sectional area in a
closed-to-open end direction.
3. The apparatus of claim 1, wherein the cross-sectional area of
the interior space proximate the open end is approximately equal to
a cross-sectional area of the exhaust outlet of the housing.
4. The apparatus of claim 1, wherein the cross-sectional area of
the exhaust outlet of the housing is approximately equal to a
maximum cross-sectional area of the exhaust flow channel.
5. The apparatus of claim 1, wherein the open end of the mesh
screen is secured directly to an interior surface of the
housing.
6. The apparatus of claim 1, wherein the exhaust inlet of the
housing is removably coupleable to an exhaust outlet of an upstream
exhaust after-treatment device.
7. The apparatus of claim 1, wherein the exhaust outlet of the
housing is configured to engage an exhaust inlet of a downstream
exhaust after-treatment device.
8. The apparatus of claim 1, wherein the housing has a length
between approximately 8 inches and approximately 10 inches.
9. The apparatus of claim 1, wherein the mesh screen comprises
sidewalls that diverge from the closed end to the open end at an
angle of at least about 5.degree..
10. An exhaust gas after-treatment system for a diesel-powered
internal combustion engine, comprising: a diesel particulate filter
in exhaust receiving communication with the diesel-powered internal
combustion engine, the diesel particulate filter comprising a
filter substrate for capturing particulate matter in the exhaust;
and an arrestor positioned downstream of the diesel particulate
filter in exhaust receiving communication with the diesel
particulate filter, the arrestor comprising a mesh screen through
which flows all exhaust received by the arrestor, wherein the mesh
screen comprises a plurality of openings sized to capture sparks
above a threshold size, the sparks being generated by the
diesel-powered internal combustion engine, and capture failed
component debris above the threshold size, the failed component
debris comprising pieces of a failed after-treatment component
upstream of the arrestor.
11. The exhaust gas after-treatment system of claim 10, further
comprising a diesel oxidation catalyst upstream of the diesel
particulate filter and a selective catalytic reduction catalyst
positioned downstream of the diesel particulate filter and upstream
of the arrestor, wherein the failed after-treatment component
comprises at least one of the diesel particulate filter, diesel
oxidation catalyst, and selective catalytic reduction catalyst.
12. The exhaust gas after-treatment system of claim 10, wherein the
arrestor is configured to induce less than about a 0.5 in-Hg
increase in exhaust gas backpressure within the exhaust gas
after-treatment system.
13. The exhaust gas after-treatment system of claim 10, wherein the
arrestor comprises an exhaust inlet and an exhaust outlet, and
wherein the mesh screen comprises a closed end and an open end
opposite the closed end, the closed end being closer to the exhaust
inlet of the arrestor than the open end.
14. The exhaust gas after-treatment system of claim 10, wherein the
arrestor comprises an exhaust inlet and an exhaust outlet, and
wherein the mesh screen comprises a closed end and an open end
opposite the closed end, the open end being closer to the exhaust
inlet of the arrestor than the closed end.
15. The exhaust gas after-treatment system of claim 10, further
comprising a component housing and an exhaust gas after-treatment
component positioned within the housing, wherein the arrestor is
positioned within the component housing downstream of the exhaust
gas after-treatment component.
16. The exhaust gas after-treatment system of claim 10, further
comprising a component housing and an exhaust gas after-treatment
component positioned within the housing, wherein the arrestor is
external and removably securable to the component housing.
17. An internal combustion engine system, comprising: a
diesel-powered internal combustion engine capable of generating an
exhaust gas stream; an exhaust gas after-treatment system in
exhaust gas receiving communication with the diesel-powered
internal combustion engine, the exhaust gas after-treatment system
comprising a diesel particulate filter comprising a filter
substrate for capturing particulate matter in the exhaust gas
stream; and an arrestor positioned downstream of the diesel
particulate filter in exhaust receiving communication with the
diesel particulate filter, the arrestor comprising a generally
tubular-shaped mesh screen through which all exhaust received by
the arrestor flows, wherein the mesh screen comprises a plurality
of openings sized to capture sparks above a threshold size, the
sparks being generated by the diesel-powered internal combustion
engine, and capture failed component debris above the threshold
size, the failed component debris comprising pieces of a failed
after-treatment component upstream of the arrestor.
18. The exhaust gas after-treatment system of claim 17, wherein the
diesel-powered internal combustion engine generates at least 50
horsepower.
19. The exhaust gas after-treatment system of claim 18, wherein the
diesel-powered internal combustion engine generates at least 500
horsepower.
20. The exhaust gas after-treatment system of claim 17, wherein the
diesel-powered internal combustion engine and exhaust gas
after-treatment system satisfy at least one of U.S. Tier 4 and
Europe Stage IIb exhaust emissions standards.
Description
FIELD
[0001] This disclosure relates to exhaust gas after-treatment
systems for internal combustion engines, and more particularly to
an apparatus and system for trapping debris and arresting sparks in
an exhaust gas after-treatment system for a diesel-powered internal
combustion engine.
BACKGROUND
[0002] Exhaust emissions regulations for internal combustion
engines have become more stringent over recent years. For example,
the regulated emissions of NO.sub.x and particulates from
diesel-powered internal combustion engines are low enough that, in
many cases, the emissions levels cannot be met with improved
combustion technologies. Therefore, the use of exhaust
after-treatment systems on engines to reduce harmful exhaust
emissions is increasing. Typical exhaust after-treatment systems
include any of various components configured to reduce the level of
harmful exhaust emissions present in the exhaust gas. For example,
some exhaust after-treatment systems for diesel-powered internal
combustion engines include various components, such as a diesel
oxidation catalyst (DOC), a particulate matter filter or diesel
particulate filter (DPF), and a selective catalytic reduction (SCR)
catalyst. In some exhaust after-treatment systems, exhaust gas
first passes through the diesel oxidation catalyst, then passes
through the diesel particulate filter, and subsequently passes
through the SCR catalyst.
[0003] Each of the DOC, DPF, and SCR catalyst components is
configured to perform a particular exhaust emissions treatment
operation on the exhaust gas passing through or over the
components. The DOC, DPF, and SCR catalyst each include a catalyst
bed or substrate that facilitates the corresponding exhaust
emissions treatment operation. Generally, the catalyst bed of the
DOC reduces the amount of carbon monoxide and hydrocarbons present
in the exhaust gas via oxidation techniques. The substrate of the
DPF filters harmful diesel particulate matter and soot present in
the exhaust gas. Finally, the catalyst bed of the SCR catalyst
reduces the amount of nitrogen oxides (NO.sub.x) present in the
exhaust gas.
[0004] Unfortunately, the substrates of the DOC, DPF, and SCR
catalyst are prone to failure due to any of various conditions,
such as age, vibrations, high temperature events, etc. Substrate
failure is often catastrophic resulting in portions of the
substrates breaking off and entering the exhaust gas. Although
typical on-board diagnostic systems alert an operator of the
failure of the components, conventional systems are not equipped to
capture the broken pieces of the failed substrates before they
enter the atmosphere. The emission of failed substrate pieces into
the atmosphere is undesirable due to the potentially harmful
effects the substrate pieces may have on the environment.
Generally, conventional diesel-powered engine systems do not
include failure mode mitigation devices to capture pieces of failed
after-treatment components due to the added size and significantly
increased exhaust restriction associated with such devices.
[0005] In addition to the above-mentioned exhaust emission
reduction requirements, current regulations require the use of
spark arrestors in engine systems for certain industrial
applications. For example, the U.S. Department of Agriculture
(USDA) requires that engine systems have spark arrestors when used
in protected environmental areas, such as forests. Compliant spark
arrestors should capture engine sparks larger than a regulated size
before the sparks are emitted into the atmosphere. Generally,
sparks include combustible materials or flaming debris that may
cause fires if emitted into the atmosphere.
[0006] Conventional spark arrestors include stator-type spark
arrestors and screen-type spark arrestors. Stator-type spark
arrestors capture sparks by creating vane-induced centrifugal
forces to separate the sparks from the exhaust gas. Screen-type
spark arrestors capture sparks using a fine mesh screen that traps
the sparks on the screen. Stator-type spark arrestors typically are
larger, bulkier, and more complex than screen-type spark arrestors
due to the significant increase in exhaust resistance that would be
induced by smaller stator-type spark arrestors. Further,
stator-type spark arrestors are inadequate to capture large sparks
or failed substrate pieces for many engine systems. Although
smaller than stator-type spark arrestors and inducing less exhaust
resistance than stator-type spark arrestors, screen-type spark
arrestors are prone to rapid soot build-up. Accordingly,
conventional screen-type spark arrestors have been relegated to use
with non-soot-producing gasoline-powered engine systems.
SUMMARY
[0007] The subject matter of the present application has been
developed in response to the present state of the art, and in
particular, in response to the problems and needs in the art that
have not yet been fully solved by currently available debris traps
and spark arrestors. Accordingly, the subject matter of the present
application has been developed to provide an apparatus and system
for trapping debris and arresting sparks that overcomes at least
some shortcomings of the prior art approaches.
[0008] According to one embodiment, an apparatus is disclosed for
mitigating failure of an exhaust after-treatment component in an
internal combustion engine system capable of generating an exhaust
gas stream. The apparatus includes a housing that includes an
exhaust inlet, exhaust outlet, and exhaust flow channel positioned
between the exhaust inlet and outlet. Also, the apparatus includes
a tubular-shaped mesh screen positioned substantially entirely
within the exhaust flow channel. The mesh screen includes a closed
end positioned proximate the exhaust inlet of the housing and an
opposing open end positioned proximate the exhaust outlet of the
housing. The mesh screen is configured to capture failed exhaust
after-treatment component particles within the exhaust gas
stream.
[0009] In certain implementations of the apparatus, the mesh screen
defines an interior space having an increasing cross-sectional area
in a closed-to-open end direction. In some implementations, the
cross-sectional area of the interior space proximate the open end
is approximately equal to a cross-sectional area of the exhaust
outlet of the housing. The cross-sectional area of the exhaust
outlet of the housing can be approximately equal to a maximum
cross-sectional area of the exhaust flow channel.
[0010] According to some implementations, the open end of the mesh
screen is secured directly to an interior surface of the housing.
The exhaust inlet of the housing can be removably coupleable to an
exhaust outlet of an upstream exhaust after-treatment device.
Similarly, the exhaust outlet of the housing can be configured to
engage an exhaust inlet of a downstream exhaust after-treatment
device. Additionally, the housing of the apparatus can have a
length between approximately 8 inches and approximately 10 inches.
In certain implementations, the mesh screen comprises sidewalls
that diverge from the closed end to the open end at an angle of at
least about 5.degree..
[0011] According to another embodiment, an exhaust gas
after-treatment system for a diesel-powered internal combustion
engine includes a diesel particulate filter and an arrestor
positioned downstream of the diesel particulate filter. The diesel
particulate filter is in exhaust receiving communication with the
diesel-powered internal combustion engine. Moreover, the diesel
particulate filter includes a filter substrate for capturing
particulate matter in the exhaust. The arrestor is in exhaust
receiving communication with the diesel particulate filter.
Additionally, the arrestor includes a mesh screen through which
flows all exhaust received by the arrestor. The mesh screen
comprises a plurality of openings sized to capture sparks above a
threshold size. The sparks are generated by the diesel-powered
internal combustion engine. The plurality of openings is also sized
to capture failed component debris above the threshold size where
the failed component debris can be pieces of a failed
after-treatment component upstream of the arrestor.
[0012] In some implementations, the exhaust gas after-treatment
system further includes a diesel oxidation catalyst upstream of the
diesel particulate filter and a selective catalytic reduction
catalyst positioned downstream of the diesel particulate filter and
upstream of the arrestor. The failed after-treatment component
comprises at least one of the diesel particulate filter, diesel
oxidation catalyst, and selective catalytic reduction catalyst. The
arrestor can be configured to induce less than about a 0.5 in-Hg
increase in exhaust gas backpressure within the exhaust gas
after-treatment system.
[0013] According to certain implementations, the arrestor includes
an exhaust inlet and an exhaust outlet. The mesh screen can include
a closed end and an open end opposite the closed end. The closed
end can be closer to the exhaust inlet of the arrestor than the
open end. Alternatively, in other implementations, the open end can
be closer to the exhaust inlet of the arrestor than the closed
end.
[0014] The exhaust gas after-treatment system can further include a
component housing and an exhaust gas after-treatment component
positioned within the housing. The arrestor can be positioned
within the component housing downstream of the exhaust gas
after-treatment component. The arrestor also can be external and
removably securable to the component housing.
[0015] According to yet another embodiment, an internal combustion
engine system includes a diesel-powered internal combustion engine
capable of generating an exhaust gas stream. The system also
includes an exhaust gas after-treatment system in exhaust gas
receiving communication with the diesel-powered internal combustion
engine. The after-treatment system includes a diesel particulate
filter with a filter substrate for capturing particulate matter in
the exhaust gas stream. The system may further include an arrestor
positioned downstream of the diesel particulate filter in exhaust
receiving communication with the diesel particulate filter. The
arrestor includes a generally tubular-shaped mesh screen through
which all exhaust received by the arrestor flows. The mesh screen
includes a plurality of openings sized to capture sparks above a
threshold size and failed component debris above the threshold
size.
[0016] In certain implementations of the internal combustion engine
system, the diesel-powered internal combustion engine generates at
least 50 horsepower. In other implementations, the diesel-powered
internal combustion engine generates at least 500 horsepower. In
some implementations, the diesel-powered internal combustion engine
and exhaust gas after-treatment system satisfy at least one of U.S.
Tier 4 and Europe Stage IIb exhaust emissions standards.
[0017] Reference throughout this specification to features,
advantages, or similar language does not imply that all of the
features and advantages that may be realized with the subject
matter of the present disclosure should be or are in any single
embodiment. Rather, language referring to the features and
advantages is understood to mean that a specific feature,
advantage, or characteristic described in connection with an
embodiment is included in at least one embodiment of the present
disclosure. Thus, discussion of the features and advantages, and
similar language, throughout this specification may, but do not
necessarily, refer to the same embodiment.
[0018] Furthermore, the described features, advantages, and
characteristics of the subject matter of the present disclosure may
be combined in any suitable manner in one or more embodiments. One
skilled in the relevant art will recognize that the subject matter
may be practiced without one or more of the specific features or
advantages of a particular embodiment. In other instances,
additional features and advantages may be recognized in certain
embodiments that may not be present in all embodiments. These
features and advantages will become more fully apparent from the
following description and appended claims, or may be learned by the
practice of the subject matter as set forth hereinafter.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] In order that the advantages of the subject matter may be
more readily understood, a more particular description of the
subject matter briefly described above will be rendered by
reference to specific embodiments that are illustrated in the
appended drawings. Understanding that these drawings depict only
typical embodiments of the subject matter and are not therefore to
be considered to be limiting of its scope, the subject matter will
be described and explained with additional specificity and detail
through the use of the drawings, in which:
[0020] FIG. 1 is a schematic block diagram of an internal
combustion engine having an exhaust gas after-treatment system and
an arrestor according to one representative embodiment;
[0021] FIG. 2 is an exploded perspective view of an exhaust gas
after-treatment system according to one embodiment;
[0022] FIG. 3 is a cross-sectional side view of an arrestor
according to one embodiment; and
[0023] FIG. 4 is a cross-sectional side view of an arrestor
according to another embodiment.
DETAILED DESCRIPTION
[0024] Reference throughout this specification to "one embodiment,"
"an embodiment," or similar language means that a particular
feature, structure, or characteristic described in connection with
the embodiment is included in at least one embodiment of the
present disclosure. Appearances of the phrases "in one embodiment,"
"in an embodiment," and similar language throughout this
specification may, but do not necessarily, all refer to the same
embodiment. Similarly, the use of the term "implementation" means
an implementation having a particular feature, structure, or
characteristic described in connection with one or more embodiments
of the present disclosure, however, absent an express correlation
to indicate otherwise, an implementation may be associated with one
or more embodiments.
[0025] Furthermore, the described features, structures, or
characteristics of the subject matter described herein may be
combined in any suitable manner in one or more embodiments. In the
following description, numerous specific details are provided, such
as examples of controls, structures, devices, algorithms,
programming, software modules, user selections, hardware modules,
hardware circuits, hardware chips, etc., to provide a thorough
understanding of embodiments of the subject matter. One skilled in
the relevant art will recognize, however, that the subject matter
may be practiced without one or more of the specific details, or
with other methods, components, materials, and so forth. In other
instances, well-known structures, materials, or operations are not
shown or described in detail to avoid obscuring aspects of the
disclosed subject matter.
[0026] FIG. 1 depicts one embodiment of an internal combustion
engine system 100. The main components of the engine system 100
include an internal combustion engine 110 and an exhaust gas
after-treatment system 120 coupled to the engine. The internal
combustion engine 110 can be a compression ignited internal
combustion engine, such as a diesel-powered engine. In some
embodiments, the diesel engine 110 outputs at least about 50
horsepower. In certain other embodiments, the diesel engine 110
outputs at least about 500 horsepower. According to some
embodiments, the internal combustion engine system 100 satisfies
advanced emissions standards, such as at least one of U.S. Tier 4
emissions standards, Europe Stage IIb emissions standards, and
beyond.
[0027] Within the internal combustion engine 110, the air from the
atmosphere is combined with fuel to power the engine. Combustion of
the fuel and air produces exhaust gas. At least a portion of the
exhaust gas generated by the internal combustion engine 110 is
operatively vented to the exhaust gas after-treatment system 120.
In certain implementations, the engine system 100 includes an
exhaust gas recirculation (EGR) line (not shown) configured to
allow a portion of the exhaust gas generated by the engine to
recirculate back into the engine for altering the combustion
properties of the engine 110.
[0028] Generally, the exhaust gas after-treatment system 120 is
configured to remove various chemical compound and particulate
emissions present in the exhaust gas received from the engine 110.
The exhaust gas after-treatment system 120 includes a diesel
oxidation catalyst (DOC) 130, a diesel particulate filter (DPF)
140, and an SCR system 150. In an exhaust flow direction, indicated
by directional arrows between the exhaust gas after-treatment
system components, exhaust may flow from the engine 110, through
the DOC 130, through the DPF 140, and through the SCR system 150.
In other words, in the illustrated embodiment, the DPF 140 is
positioned downstream of the DOC 130, and the SCR system 150 is
positioned downstream of the DPF 140. In other embodiments, the
components of the exhaust gas after-treatment system 120 can be
positioned in any of various arrangements, and the system can
include other components, such as an AMOX catalyst (not shown)
downstream of the SCR system 150, or fewer components. Generally,
exhaust gas treated in the exhaust gas after-treatment system 120
and released into the atmosphere consequently contains
significantly fewer pollutants, such as diesel particulate matter,
NO.sub.x, hydrocarbons, such as carbon monoxide and carbon dioxide,
than untreated exhaust gas.
[0029] The DOC 130 can be any of various flow-through oxidation
catalysts. Generally, the DOC 130 includes a substrate with an
active catalyst layer configured to oxidize at least some
particulate matter (e.g., the soluble organic fraction of soot) in
the exhaust and reduce unburned hydrocarbons and CO in the exhaust
to less environmentally harmful compounds. For example, in some
implementations, the DOC 130 may sufficiently reduce the
hydrocarbon and CO concentrations in the exhaust to meet the
requisite emissions standards.
[0030] The DPF 140 can be any of various particulate filters known
in the art configured to reduce particulate matter concentrations,
e.g., soot and ash, in the exhaust gas to meet requisite emission
standards. The DPF 140 includes a filter substrate that captures
soot and other particular matter generated by the engine 110. The
engine system 100 periodically regenerates the DPF 140 to remove
particulate matter that has accumulated on the DPF over time.
Basically, the DPF 140 is regenerated by increasing the temperature
of the exhaust gas above a threshold temperature corresponding with
combustion of the particulate matter.
[0031] The SCR system 160 includes a reductant delivery system and
an SCR catalyst downstream of the reductant delivery system. The
reductant delivery system is operable to inject or dose a reductant
into the exhaust gas prior to the gas entering the SCR catalyst.
The injected reductant (or broken-down byproducts of the reductant,
such as when urea is reduced to form ammonia) reacts with NO.sub.x
in the presence of the SCR catalyst to reduce NO.sub.x in the
exhaust gas to less harmful emissions, such as N.sub.2 and
H.sub.2O. The SCR catalyst can be any of various catalysts known in
the art. For example, in some implementations, the SCR catalyst is
a vanadium-based catalyst, and in other implementations, the SCR
catalyst is a zeolite-based catalyst, such as a Cu-Zeolite or a
Fe-Zeolite catalyst Like the filter substrate of the DPF 140, the
SCR catalyst can be subject to high temperatures, such as during a
regeneration event on the DPF.
[0032] Each of the catalyst or filter substrates of the DOC 130,
DPF 140, and SCR system 150 are subject to failure due to any of
various conditions. For example, high exhaust temperature events
(e.g., DPF regeneration events), high vibration environments, and
relative age of the subjects can each lead to failure of the
substrates. Failure of the substrates can be minor (e.g., crack
formation) and major (e.g., disintegration of the substrate). Minor
failures of the substrates can be detectable and correctible before
substantially negatively impacting the environment. Major failures,
however, often are not correctible before pieces of the substrate
are emitted into the environment. Conventional diesel-powered
engine systems employing exhaust after-treatment components do not
have failed substrate debris traps, particularly when the failed
substrate is associated with a DPF or downstream SCR catalyst.
Accordingly, for diesel-powered engine systems, failed substrate
debris would be emitted into the environment before mitigating
actions could be implemented.
[0033] In addition to the possibility of substrate emissions due to
a major failure of a substrate of an exhaust after-treatment
component, internal combustion engines are susceptible to spark
emissions. Because of the hazardous and combustible nature of spark
emissions, the USDA requires the implementation of spark arrestors
in certain engine systems when used within protected areas. One
common application includes the use of engine systems in certain
vehicles and/or non-vehicular equipment operated in forested areas.
Conventionally, to satisfy the USDA regulations regarding spark
arrestors, gasoline-powered engine systems use screen-type spark
arrestors and diesel-powered engine systems use stator-type spark
arrestors. Screen-type spark arrestors are more conducive to
gasoline-powered engine systems due to the smaller size and reduced
restriction properties of screen-type spark arrestors. Stator-type
spark arrestors are conventionally used with diesel-powered engine
systems because the high soot and particular matter output of
previous diesel engines would rapidly clog screen-type
arrestors.
[0034] Although contrary to conventional techniques, the diesel
engine system 100 of the present disclosure includes a screen-type
arrestor 160 or particle trap downstream of the DOC 130, DPF 140,
and SCR system 150 to provide the dual functionality of a failed
substrate debris trap and spark accumulator (see FIG. 1).
Generally, the arrestor 160 receives 100% of the exhaust gas
flowing through the DOC 130, DPF 140, and SCR system 150. The
arrestor 160 mitigates the major failure of exhaust after-treatment
system components by capturing pieces or disintegrated portions of
failed components on a mesh-like screen before they are emitted
into the environment. Similarly, the mesh-like screen of the
arrestor 160 is configured to captures sparks emitted from the
diesel engine 110 before they are emitted into the environment in
compliance with USDA requirements. In some implementations, the
arrestor 160 is in-line with and separately connectible to the
components of the exhaust after-treatment system 120. For example,
in one implementation, the DOC 130, DPF 140, and SCR catalyst of
the SCR system 150 are housed within a single housing having a
housing outlet. In this implementation, the arrestor 160 can be
removably coupled to the housing outlet. In other implementations,
the arrestor 160 is integrated into the housing of an
after-treatment component, such as an outlet section of the SCR
system 150. For example, the arrestor 160 can be positioned within
an after-treatment component housing just upstream of the housing
outlet.
[0035] As shown in FIG. 2, a diesel engine system 200 includes an
exhaust gas after-treatment system 220 having an arrestor 230
according to one embodiment. The after-treatment system 220
includes an after-treatment component housing or can 210 within
which is housed one or more emissions-reducing components. In one
embodiment, the housing 210 houses at least one of a DOC, DPF, and
SCR catalyst. In the illustrated embodiment, the housing 210 houses
at least a DPF. The housing 210 includes an exhaust inlet 212 and
an exhaust outlet 214. Exhaust gas generated by an engine flows
into the housing through the inlet 212, the component(s) within the
housing 210 reduce emissions within the exhaust gas, and the
exhaust gas flows out of the housing through the outlet 214. The
housings of the present disclosure can be made from any of various
materials, such as metal or metal alloys.
[0036] The arrestor 230 includes a housing 231 extending from an
inlet end 232 to an outlet end 234. In certain implementations, the
housing 231 is a generally cylindrically-shaped hollow canister.
The inlet end 232 of the housing 231 defines an inlet and the
outlet end 234 of the housing defines an outlet of the arrestor
230. The housing 231 houses a mesh screen 236 extending from a
closed inlet end 250 proximate the inlet end 232 of the housing 231
to an open outlet end (not shown) proximate (e.g., adjacent,
adjoining, and/or coextensive with) the outlet end 234 of the
housing. The mesh screen 236 is arranged (e.g., wrapped about
itself) to form a 3-dimensional shape that defines an interior
space. Exhaust gas entering the housing 231 via the inlet at the
inlet end 232 passes through the mesh screen 236 into the interior
space before exiting the housing via the outlet at the outlet end
234. Because the closed inlet end 250 of the mesh screen 236 is
closed or plugged and the open outlet end is generally coextensive
with the outlet end 234 of the housing 231, all exhaust gas
entering the housing 231 of the arrester 230 passes through the
mesh screen 236.
[0037] The mesh screen 236 can be arranged in any of various
arrangements. Preferably, the mesh screen 236 is generally elongate
and tubular-shaped to define a hollow interior channel. The mesh
screen can have any of various shapes such that the hollow interior
channel has any of various cross-sectional shapes and still be
generally tubular. In other words, the mesh screen 236 can be
non-cylindrical and still be tubular. To conserve space while
improving performance, the closed inlet end 250 of the screen 236
can be collapsed and crimped to form a generally "X-shaped" or
"+-shaped" plug 252. As the screen 236 extends from the closed
inlet end 250 toward the open outlet end, the screen gradually
unfolds or expands into a generally circular-shaped opening at the
open outlet end. Although the closed inlet end 250 of the
illustrated embodiment is generally "X-shaped" or "+-shaped," in
other embodiments, the closed inlet end of the mesh screen 236 can
have other shapes, such as circular, rounded, pointed, polygonal,
linear, etc.
[0038] The mesh screen 236 includes a plurality of openings having
a specific size, shape, and number. The size and shape of the
openings are selected to allow particles below a threshold size to
pass through and prevent passage of particles above the threshold
size. The threshold size can be any of various selectable sizes
based on any of various factors. However, in certain
implementations, the threshold size is based on governmentally
regulated thresholds. For example, in one implementation, each
opening of the mesh sheet has a maximum dimension of about 0.023
inches. Generally, the number of openings is maximized under the
constraints of the material from which the mesh screen 236 is made.
Preferably, the mesh screen 236 is made from a metallic wire mesh
screen, such as a stainless steel wire mesh screen. In these
implementations, the number of particles is based on the size and
strength of the wires forming the screen. In other implementations,
the mesh screen 236 is made from a closely perforated material. The
mesh screen 236 is also configured to reduce exhaust backpressure
inducement. For example, in certain implementations, the increase
in exhaust gas backpressure (e.g., restriction) induced by the
arrestor is less than about 0.5 in-Hg.
[0039] The arrestor 230 is removably coupled to the exhaust outlet
214 of the housing 210. The inlet end 232 of the arrestor housing
231 includes a stepped portion that is sized to receive the exhaust
outlet 214 of the housing 210. More specifically, the inner
diameter of the inlet end 232 is approximately the same as the
outer diameter of the exhaust outlet 214, while the inner diameter
of the inlet end 232 is approximately the same as the inner
diameter of the exhaust outlet 214. In this manner, the exhaust
outlet 214 is nestably received within the inlet end 232 of the
arrestor housing 231 with the inner surfaces of the exhaust outlet
214 and arrestor inlet end 232 being substantially flush. The inlet
end 232 can include notches (see, e.g., notches 380 of FIG. 3) to
facilitate tightening of the inlet end about the exhaust outlet
214. In the illustrated embodiment, the inlet end 232 is tightened
about the exhaust outlet 214 via a clamp 238 wrapped around the
inlet end.
[0040] Another exhaust after-treatment component 220 and housing
221 can be coupled to the outlet end 234 of the arrestor 230 if
desired. For example, in certain implementations, the component 220
can be a muffler device with a housing having an exhaust inlet 222.
Similar to the inlet end 232 of the arrestor 230, the exhaust inlet
222 of the housing 221 matingly receives the outlet end 234 of the
arrestor. The exhaust inlet 222 of the component 220 is tightened
to the outlet end 234 via a clamp 224 similar to clamp 238.
[0041] The removable connection between the component housings 210,
221 and the arrestor 230 promote the serviceability of the arrestor
230. For example, when the arrestor 230 becomes full of captured
particles, the arrestor 230 can be easily serviced by loosening the
clamps 224, 238 and removing the arrestor 230. Following service of
the arrestor 230 (e.g., removing the capture particles from the
screen 236), the arrestor 230 can be reinstalled on the system 200
by matingly engaging the exhaust outlet 214 of the housing 210 and
inlet end 232 of the arrestor, matingly engaging the exhaust inlet
222 of the housing 221 and the outlet end 234 of the arrestor, and
tightening the clamps 224, 238. Alternatively, the serviced
arrestor 230 can be installed on a different system. In this
manner, the arrestor 230 is easily serviceable and reusable on the
same or a different system.
[0042] According to another embodiment shown in FIG. 3, an arrestor
330 similar to arrestor 230 includes a housing 331 extending from
an inlet end 332 to an outlet end 334. In certain implementations,
the housing 331 is a tube or can with an exterior surface 371
exposed to the environment and an interior surface 372 opposite the
exterior surface. The housing 331 defines an interior exhaust flow
channel 344 through which exhaust flows from an inlet 333 defined
by the inlet end 332 to an outlet 335 defined by the outlet end
334. The housing 331 has a length equal to the distance between the
inlet end 332 and the outlet end 334. In certain implementations,
the length of the housing is between about eight inches and about
ten inches. Also, in some implementations, the approximate diameter
of the interior exhaust flow channel 344 is between about four
inches and about five inches. In one specific implementation, the
housing 331 has a length of about eight inches and an inside
diameter of about four inches (i.e. a length-to-diameter ratio of
about 0.5). In another specific implementation, the housing 331 has
a length of about ten inches and an inside diameter of about five
inches (i.e. a length-to-diameter ratio of about 0.5).
[0043] Like the arrestor 230, the arrestor 330 includes a mesh
screen 336 extending from a closed end 340 to an open end 342. The
mesh screen 336 is shaped to define an interior space 345. The
closed or plugged end 340 is collapsed and forms a generally
"X-shaped" or "+-shaped" plug 346 similar to the closed end 250 of
the mesh screen 236 of arrestor 230. The plug 346 can be formed by
crimping the closed end 340 of the screen 336 using any of various
crimping techniques. The open end 342 defines a generally
circular-shaped opening. Accordingly, the cross-sectional shape of
the interior space 345 along a plane perpendicular to the exhaust
flow direction 360 gradually transitions from a generally "X-shape"
or "+-shape" to a generally circular shape. Similarly, the
cross-sectional area of the interior space 345 along a plane
perpendicular to the exhaust flow direction 360 gradually increases
from a minimum area proximate the plug 346 to a maximum area
proximate the open end 342. As shown, the maximum cross-sectional
area of the interior space 345 along a plane perpendicular to the
exhaust flow direction 360 is about equal to a maximum
cross-sectional area of the interior channel 344 (excluding the
portion of the interior channel 344 defined by the coupling step
370 at the inlet portion 332).
[0044] The radially outermost portions or sidewalls 352 of the mesh
screen 336 are angled radially outwardly in an exhaust flow
direction indicated by directional arrows 360, 364. In other words,
the radially outermost sidewall 352 of the mesh screen 336 diverges
in the exhaust flow direction 360, 364. In some implementations,
the radially outermost sidewall 352 diverges at an angle .theta.
between about 5.degree. and about 60.degree.. In one particular
implementation, the angle .theta. is about 30.degree.. The mesh
type and configuration of the screen 336 can be similar to the
screen 236.
[0045] The mesh screen 336 has a length defined as the distance
between the closed end 340 and the open end 342. In the illustrated
embodiment, the length of the mesh screen 336 is less than a length
of the housing 331 defined between the inlet end 332 and the outlet
end 334. Accordingly, in the illustrated embodiment, the mesh
screen 336 is entirely contained within the housing 331. The mesh
screen 336 is coupled to the housing 331 via engagement between a
tab portion 354 of the open end 342 of the mesh screen 336 and the
interior surface 372 of the housing. More specifically, the tab
portion 354 is adhered or welded to the interior surface 372 of the
housing 331. In this manner, the mesh screen is secured directly to
an interior surface 372 of the housing or can 331. In other
embodiments, the mesh screen 336 is secured to the housing 331 by
using other attachment or coupling techniques. Notwithstanding the
method of securing the open end 342 to the housing 331, the mesh
screen 336 is cantilevered such that the closed end 340 is a free
or non-fixed end.
[0046] In operation, as shown in FIG. 3, exhaust gas 360 containing
undesirable particles 375 (e.g., failed substrate debris and/or
engine sparks) enter the housing 331 of the arrestor 330 via the
inlet 333. After passing through the inlet 333, the exhaust gas 360
enters a space 348 defined between the mesh screen 236 and the wall
of the housing 331. From the space 348, the exhaust gas 360 passes
through the plurality of openings 350 in the mesh screen 336 into
the interior space 345 as indicated by directional arrows 362. From
the interior space 345, the exhaust gas exits the arrestor 330
through the outlet 335 as indicated by directional arrows 364. As
the exhaust gas 362 passes through the mesh screen 336, undesirable
particles 375 above a threshold size are captured on the radially
outward facing surface 353 of the mesh screen. Particles smaller
than the threshold size are allowed to pass through the openings of
the mesh screen 336 along with the exhaust gas 362.
[0047] The arrestors 230, 330 described above are configured as a
stand-alone component positionable in-line with other components of
an exhaust after-treatment system. In other words, the arrestors
230, 330 are physically independent from the other components of
the system. However, in some embodiments, an arrestor of the
present disclosure for capturing failed substrate particles and
sparks can be integrated into an existing component of an
after-treatment system. For example, as shown in FIG. 4, an
arrestor 430 according to one embodiment forms part of an existing
component 420 of an after-treatment system. The existing component
420 can be an exhaust outlet section of a housing 410 within which
a conventional exhaust emissions-reducing component (e.g., DOC,
DPF, SCR catalyst) is positioned. The exhaust outlet section 420
includes a housing 422 extending between an exhaust inlet end 432
and exhaust outlet end 434. Exhaust gas 460 from the housing 410
flows into the outlet section 430 through the inlet end 432 and out
of the outlet section through the outlet end 434.
[0048] The arrestor 430 includes a mesh screen 436 similar to the
mesh screens 236, 336. However, the mesh screen 436 is shaped and
arranged in a manner different than the mesh screens 236, 336. For
example, the mesh screen 436 includes an open inlet end 440 and a
closed outlet end 445. The mesh screen 436 may have a generally
circular cross-sectional shape along a plane perpendicular to the
exhaust flow direction 460 that gradually decreases in area in the
exhaust flow direction. In other embodiments, the mesh screen 436
can have other cross-sectional shapes as desired with decreasing
cross-sectional areas in the exhaust flow direction. The open inlet
end 440 is coextensive with the exhaust inlet end 432 of the
housing 422 such that all exhaust gas passing through the exhaust
inlet end 432 of the housing 422 passes through the open inlet end
440 of the mesh screen 436. In certain implementations, the open
inlet end 440 is secured (e.g., welded) to an interior surface of
the housing 422 proximate the exhaust inlet end 432.
[0049] In operation, exhaust gas 460 containing undesirable
particles 470 enters the outlet section 420 via the inlet end 432.
After passing through the inlet end 432, the exhaust gas 460 passes
through the open inlet end 440 of the arrestor 430 and enters a
space 444 defined within the mesh screen 436. From the space 444,
the exhaust gas 460 passes through a plurality of openings 450 in
the mesh screen 436 and exits the arrestor 430 as indicated by
directional arrows 462. After exiting the arrestor 430, the exhaust
gas exits the outlet section 420 by passing through the outlet end
434 as indicated by directional arrows 464. As the exhaust gas 462
passes through the mesh screen 436, undesirable particles 470 above
a threshold size are captured on the radially inward facing surface
452 of the mesh screen. Particles smaller than the threshold size
are allowed to pass through the openings of the mesh screen 436
along with the exhaust gas 462.
[0050] The mesh screen 336 of the arrestor 330 is oriented in a
closed-to-open end orientation relative to the exhaust flow
direction 360. In contrast, the mesh screen 436 of the arrestor 430
is oriented in an open-to-closed end orientation relative to the
exhaust flow direction 460. Although not shown, in some
embodiments, the mesh screen 336 is oriented in an open-to-closed
end orientation relative to the exhaust flow direction 360 and the
mesh screen 436 is oriented in a closed-to-open end orientation
relative to the exhaust flow direction 460. Further, in embodiments
of the mesh screen 436 in the closed-to-open end orientation, the
closed end 445 of the mesh screen can be positioned outside of the
outlet section 420 (e.g., upstream of the inlet end 432 of the
outlet section within the component housing 210). Additionally,
although the mesh screen 436 has a generally circular-shaped
cross-section along its length, the mesh screen 436 can be shaped
in a manner similar to the mesh screens 236, 336 of the arrestors
230, 330, respectively.
[0051] The present subject matter may be embodied in other specific
forms without departing from its spirit or essential
characteristics. The described embodiments are to be considered in
all respects only as illustrative and not restrictive. The scope of
the invention is, therefore, indicated by the appended claims
rather than by the foregoing description. All changes which come
within the meaning and range of equivalency of the claims are to be
embraced within their scope.
* * * * *