U.S. patent application number 14/798533 was filed with the patent office on 2015-11-05 for modular aftertreatment assembly.
This patent application is currently assigned to Caterpillar Inc.. The applicant listed for this patent is Caterpillar Inc.. Invention is credited to David A. Akers, Raymond U. Isada, Chiranjeevi Mangamuri, Thomas W. Manning, Kevin Weiss.
Application Number | 20150315948 14/798533 |
Document ID | / |
Family ID | 54354914 |
Filed Date | 2015-11-05 |
United States Patent
Application |
20150315948 |
Kind Code |
A1 |
Weiss; Kevin ; et
al. |
November 5, 2015 |
MODULAR AFTERTREATMENT ASSEMBLY
Abstract
A modular aftertreatment assembly for an engine system is
provided. The modular aftertreatment assembly includes a housing
having a first section, a second section, and a third section. The
modular aftertreatment assembly also includes a mixing tube
positioned within and extending from the second section of the
housing. The modular aftertreatment assembly further includes a
diffusion assembly having a first diffusion and a second diffusion
plate. The modular aftertreatment assembly includes a selective
catalytic reduction assembly. The modular aftertreatment assembly
also includes a plurality of perforations provided on an outlet
face of the first bank of the plurality of catalysts and the second
bank of the plurality of catalysts respectively. The modular
aftertreatment assembly further includes a pair of outlets provided
in association with the first and third sections of the housing
respectively.
Inventors: |
Weiss; Kevin; (Peoria,
IL) ; Isada; Raymond U.; (Peoria, IL) ; Akers;
David A.; (Morton, IL) ; Manning; Thomas W.;
(Metamora, IL) ; Mangamuri; Chiranjeevi; (Peoria,
IL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Caterpillar Inc. |
Peoria |
IL |
US |
|
|
Assignee: |
Caterpillar Inc.
Peoria
IL
|
Family ID: |
54354914 |
Appl. No.: |
14/798533 |
Filed: |
July 14, 2015 |
Current U.S.
Class: |
422/176 |
Current CPC
Class: |
F01N 2610/02 20130101;
F01N 3/2066 20130101; Y02T 10/24 20130101; F01N 13/017 20140601;
F01N 3/28 20130101; Y02T 10/12 20130101; F01N 3/2892 20130101; F01N
2590/08 20130101 |
International
Class: |
F01N 3/28 20060101
F01N003/28; F01N 3/20 20060101 F01N003/20 |
Claims
1. A modular aftertreatment assembly for an engine system, the
modular aftertreatment assembly comprising: a housing having a
first section, a second section, and a third section, wherein the
first section, the second section, and the third section are
positioned adjacent to each other in a parallel arrangement, such
that the second section is centrally disposed within the housing; a
mixing tube positioned within and extending from the second section
of the housing, the mixing tube having an inlet end and an outlet
end, the inlet end of the mixing tube configured to couple to an
exhaust conduit of the engine system, and wherein the outlet end of
the mixing tube includes a plurality of slots on a top facing
surface and a bottom facing surface of the mixing tube; a diffusion
assembly including a first diffusion plate positioned between the
first and second sections of the housing, and a second diffusion
plate positioned between the second and third sections of the
housing, the first and second diffusion plates including a
plurality of openings respectively, wherein the diffusion assembly
is positioned parallel to the mixing tube; a selective catalytic
reduction assembly including a first bank of a plurality of
catalysts and a second bank of a plurality of catalysts, wherein
the first bank of the plurality of catalysts is positioned within
the first section of the housing, and wherein the second bank of
the plurality of catalysts is positioned within the third section
of the housing; a plurality of perforations provided on an outlet
face of the first bank of the plurality of catalysts and the second
bank of the plurality of catalysts respectively; and a pair of
outlets provided in association with the first and third sections
of the housing respectively.
Description
TECHNICAL FIELD
[0001] The present disclosure relates to an aftertreatment
assembly, and more particularly to a modular aftertreatment
assembly for an engine system.
BACKGROUND
[0002] An aftertreatment assembly is associated with an engine
system. The aftertreatment assembly is configured to treat and
reduce oxides of nitrogen (NOx) present in an exhaust gas flow,
prior to the exhaust gas flow exiting into the atmosphere. In order
to reduce NOx, the aftertreatment system may include a reductant
injector, a mixing tube, and a Selective Catalytic Reduction (SCR)
module. The reductant injector is configured to inject a reductant
into the exhaust gases, before the exhaust gases flow through the
SCR module.
[0003] In some applications, the components of the aftertreatment
assembly, such as the SCR module and the mixing tube, occupy a
large amount of space in an engine enclosure. Accordingly, in case
of small size applications having spatial constraints, it may be
difficult to accommodate such large sized aftertreatment components
within a confined space. However, re-sizing the aftertreatment
components to accommodate the aftertreament assembly in the
confined space may affect an overall working and efficiency of the
aftertreatment assembly. For example, in some situations, smaller
sized aftertreatment components have other operational issues, such
as an increase in back pressure experienced by the components of
aftertreatment assembly.
[0004] U.S. Pat. No. 8,752,370, hereinafter referred to as '370
patent, describes an exhaust aftertreatment system including
housing with two or more inlets configured to receive separate
entering exhaust streams from an engine. The system includes two or
more first exhaust treatment devices, each configured to receive
one of the separate entering exhaust streams in a first direction.
The system further includes two or more redirecting flow passages
configured to combine the separate exhaust streams into a merged
exhaust stream that flows in a second direction about 180 degrees
from the first direction and an intermediate flow region configured
to divide the merged exhaust stream into two or more separate
exiting exhaust streams. The system also includes two or more
second exhaust treatment devices, each configured to receive one of
the separate exiting exhaust streams in a third direction about 90
degrees from the second direction.
[0005] In the '370 patent, the components of the exhaust
aftertreatment system include two separate inlets for receiving
separate exhaust streams from the engine. Further, the design of
the exhaust aftertreatment system of the '370 patent is not
compact, and the components of the exhaust aftertreatment system do
not fit in a small space.
SUMMARY OF THE DISCLOSURE
[0006] In one aspect of the present disclosure, a modular
aftertreatment assembly for an engine system is provided. The
modular aftertreatment assembly includes a housing having a first
section, a second section, and a third section. The first section,
the second section, and the third section are positioned adjacent
to each other in a parallel arrangement, such that the second
section is centrally disposed within the housing. The modular
aftertreatment assembly also includes a mixing tube positioned
within and extending from the second section of the housing. The
mixing tube includes an inlet end and an outlet end. The inlet end
of the mixing tube is configured to couple to an exhaust conduit of
the engine system. Further, the outlet end of the mixing tube
includes a plurality of slots on a top facing surface and a bottom
facing surface of the mixing tube. The modular aftertreatment
assembly further includes a diffusion assembly having a first
diffusion plate positioned between the first and second sections of
the housing, and a second diffusion plate positioned between the
second and third sections of the housing. The first and second
diffusion plates include a plurality of openings respectively. The
diffusion assembly is positioned parallel to the mixing tube. The
modular aftertreatment assembly includes a selective catalytic
reduction assembly having a first bank of a plurality of catalysts
and a second bank of a plurality of catalysts. The first bank of
the plurality of catalysts is positioned within the first section
of the housing and the second bank of the plurality of catalysts is
positioned within the third section of the housing. The modular
aftertreatment assembly also includes a plurality of perforations
provided on an outlet face of the first bank of the plurality of
catalysts and the second bank of the plurality of catalysts
respectively. The modular aftertreatment assembly further includes
a pair of outlets provided in association with the first and third
sections of the housing respectively.
[0007] Other features and aspects of this disclosure will be
apparent from the following description and the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is a perspective view of an exemplary engine system
and a modular aftertreatment assembly provided in association with
the engine system, according to one embodiment of the present
disclosure;
[0009] FIG. 2 is a perspective view of the modular aftertreatment
assembly, according to one embodiment of the present disclosure;
and
[0010] FIG. 3 is a perspective view of a mixing tube and a
diffusion assembly associated with the modular aftertreatment
assembly of FIG. 2, according to one embodiment of the present
disclosure; and
[0011] FIG. 4 is a perspective view of a portion of a selective
catalytic reduction assembly associated with the modular
aftertreatment assembly of FIG. 2, according to one embodiment of
the present disclosure.
DETAILED DESCRIPTION
[0012] Wherever possible, the same reference numbers will be used
throughout the drawings to refer to the same or the like parts.
FIG. 1 is a perspective view of an exemplary engine system 100,
according to one embodiment of the present disclosure. In one
embodiment, the engine system 100 may be associated with a
locomotive (not shown). However, it should be noted that the
application of the present disclosure is not restricted to the
locomotive. The engine system 100 may be used to provide power to
any machine including, but not limited to, an on-highway truck, an
off-highway truck, an earth moving machine, and other similar
machines.
[0013] As shown in the accompanying figures, the engine system 100
is mounted on a frame 102 of the locomotive. The engine system 100
includes an engine 104. The engine 104 provides driving power to
the locomotive, in order to propel the locomotive on rails (not
shown). In one embodiment, the engine 104 may include, for example,
a diesel engine, a gasoline engine, a gaseous fuel powered engine
such as, a natural gas engine, a combination of known sources of
power, or any other type of power source apparent to one of skill
in the art. The engine 104 may include an intake manifold (not
shown) and an exhaust manifold (not shown). The intake manifold is
configured to receive intake air through an air intake system.
Products of combustion may be exhausted from the engine 104 via the
exhaust manifold of the engine 104. Additionally, the locomotive
may include other components, such as, a fuel system (not shown)
and an aftercooler 106 associated with the engine 104 and a torque
converter 108.
[0014] The engine system 100 includes a modular aftertreatment
assembly 200. The modular aftertreatment assembly 200 is configured
to treat the exhaust gases exiting the exhaust manifold of the
engine 104. The modular aftertreatment assembly 200 is provided in
fluid communication with the exhaust manifold of the engine 104 via
an exhaust conduit (not shown).
[0015] Referring to FIG. 2, the modular aftertreatment assembly 200
includes a housing 202. The housing 202 is embodied as a generally
rectangular cuboid.ca The housing 202 may be made of a metal, based
on system requirements. Dimensions of the housing 202 may vary
based on an amount of the exhaust gases that may be received by the
modular aftertreatment assembly 200. The housing 202 includes
bracket elements 204 for receiving mechanical fasteners in order to
mount the modular aftertreatment assembly 200 on a work surface.
The bracket elements 204 may include isolation components to
isolate transfer of any vibrations to and from the modular
aftertreatment assembly 200. The housing 202 includes a first
section 206, a second section 208, and a third section 210. The
first, second, and third sections 206, 208, 210 are positioned
adjacent to each other in a parallel arrangement. The second
section 208 is centrally disposed between the first and third
sections 206, 210 of the housing 202.
[0016] Each of the first, second, and third sections 206, 208, 210
are embodied as separate components and are assembled together to
form the housing 202. Each of the first, second, and third sections
206, 208, 210 include flanges 212, 214, 216 (see FIGS. 3 and 4)
respectively for receiving mechanical fasteners in order to couple
the first section 206 with the second section 208 and the second
section 208 with the third section 210 respectively. Alternatively,
the housing 202 may embody a unitary component with the first,
second, and third sections 206, 208, 210 defined therein. For
illustrative and explanation purposes, some portions of the first,
second, and third sections 206, 208, 210 are shown transparent in
the accompanying figures, in order to depict mounting positions and
details of the components of the modular aftertreatment assembly
200 present therein.
[0017] A reductant injector 236 is positioned along a mixing tube
218, close to an inlet end 220 thereof. A reductant is injected
into the mixing tube 218 by the reductant injector 236. The
reductant may be a fluid, such as, Diesel Exhaust Fluid (DEF). The
reductant may include urea, ammonia, or other reducing agent known
in the art. The reductant may be received from a reductant tank
(not shown) associated with the engine system 100.
[0018] Referring to FIGS. 2 and 3, the second section 208 of the
housing 202 defines an interior space therewithin. The interior
space is configured to receive the mixing tube 218. A portion of
the mixing tube 218 extends outwards from the second section 208 of
the housing 202. The mixing tube 218 includes the inlet end 220 and
an outlet end 222, such that the inlet end 220 is positioned
externally with respect to the second section 208 of the housing
202. The inlet end 220 of the mixing tube 218 is coupled to the
exhaust conduit of the engine 104, and is configured to receive a
main stream 228 of the exhaust gases therefrom. The modular
aftertreatment assembly 200 of the present disclosure has a single
inlet to receive the exhaust gases into the modular aftertreatment
assembly 200. A direction of flow of the exhaust gases into and
within the modular aftertreatment assembly 200 is shown using
arrows "F" in FIG. 2. The inlet end 220 includes a circular flange
portion 224 to couple the mixing tube 218 to the exhaust
conduit.
[0019] Additionally or optionally, in order to promote mixing of
the reductant with the main stream 228 of the exhaust gases, a
mixing element 238 is associated with the modular aftertreatment
assembly 200. The mixing element 238 is provided within the mixing
tube 218. The mixing element 238 is positioned downstream of the
reductant injector 236, with respect to the flow direction "F" of
the exhaust gases. In one embodiment, the mixing element 238 may
include a flapper style mixer. Alternatively, the mixing element
238 may include a swirl plate mixer. Although a single mixing
element 238 is illustrated herein, the modular aftertreatment
assembly 200 may include two or more mixing elements, such that a
type of each of the mixing elements may be same or different, based
on system requirements.
[0020] The mixing tube 218 includes the outlet end 222. As shown in
the accompanying figures, the outlet end 222 includes a number of
slots 226. The slots 226 extend in a direction parallel to the flow
"F" of the exhaust gases. The slots 226 have an oblong shape and
are provided on a top facing surface 234 and a bottom facing
surface (not shown) of the mixing tube 218. The main stream 228 of
the exhaust gases enters the modular aftertreatment assembly 200
from the inlet end 220, flows towards the outlet end 222, and
further divides into a first exhaust gas flow 230 and a second
exhaust gas flow 232 (see FIG. 2) on impacting an end surface of
the second section 208.
[0021] The first and second exhaust gas flows 230, 232 are
re-routed or directed towards the first and the third sections 206,
210 respectively, through the slots 226. The slots 226 provide
fluid communication between the mixing tube 218 and each of the
first, second, and third sections 206, 208, 210 of the housing 202.
In one example, a length of the slots 226 is approximately
1/4.sup.th of a length of the housing 202. The mixing tube 218 is
formed by a single tube having the slots 226 provided thereon.
Alternatively, the mixing tube 218 may include a two piece design
such that one of the tubes includes the slots 226 provided
thereon.
[0022] Referring to FIG. 3, the modular aftertreatment assembly 200
includes a diffusion assembly 240. The diffusion assembly 240 is
positioned parallel to the mixing tube 218. The diffusion assembly
240 includes a first diffusion plate 242 and a second diffusion
plate 244. The first diffusion plate 242 is positioned between the
first section 206 and the second section 208. Further, the second
diffusion plate 244 is positioned between the second section 208
and the third section 210. The first and second diffusion plates
242, 244 may perform a flow distribution function to guide and
evenly distribute the exhaust gas flow 230, 232 (see FIG. 2) across
a face of the respective diffusion plates 242, 244.
[0023] Each of the diffusion plates 242, 244 respectively include a
number of openings 246, 248 provided across the face of the
diffusion plates 242, 244. Further, each of the diffusion plates
242, 244 includes eight sections such that a sizing of the openings
246, 248 of each of the eight sections are different in order to
individually tune the exhaust gas flow 230, 232 across the face of
the respective diffusion plates 242, 244. More particularly, the
number of openings 246, 248 is provided such that the sizing of the
openings 246, 248 decreases in diameter along the direction "F" of
the main stream 228 of the exhaust gases (see FIG. 2). The openings
246, 248 that are smaller in diameter are provided close to the
outlet end 222 of the mixing tube 218. Such small diameter openings
246, 248 act as a restriction to the exhaust gas flow 230, 232
passing therethrough, and further direct the respective exhaust gas
flows 230, 232 towards the openings 246, 248 having a comparatively
larger diameter. The openings 246, 248 that are larger in diameter
size are provided close to the inlet end 220 of the mixing tube
218, with respect to the direction "F" of the main stream 228 of
the exhaust gases.
[0024] As shown in FIGS. 2 and 4, the modular aftertreatment
assembly 200 includes a selective catalytic reduction (SCR)
assembly 250. The SCR assembly 250 operates to treat exhaust gases
exiting the engine 104 in the presence of ammonia, which is
provided after degradation of the reductant injected into the main
stream 228 of the exhaust gases near the inlet end 220. The SCR
assembly 250 includes a first bank of catalysts 252. The first bank
of catalysts 252 includes a number of catalysts 254 (see FIG. 4).
The first bank of catalysts 252 is positioned within the first
section 206 of the housing 202. The SCR assembly 250 also includes
a second bank of catalysts 256 having a number of catalysts 258.
The second bank of catalysts 256 is positioned within the third
section 210 of the housing 202.
[0025] For illustrative purposes, the first bank of catalyst 252
associated with the first section 206 will now be explained in
detail. However, it should be noted that the description of the
first bank of catalyst 252 given below is equally applicable to the
second bank of catalyst 256 associated with the third section 210,
without limiting the scope of the present disclosure. Referring to
FIGS. 2 and 4, the first bank of catalysts 252 is in fluid
communication with the mixing tube 218 via the first diffusion
plate 242 and the slots 226. The first diffusion plate 242 is
arranged such that the first diffusion plate 242 distributes the
first exhaust gas flow 230 (see FIG. 2) uniformly across inner
faces (not shown) of the catalysts 254.
[0026] As shown in FIG. 4, the catalysts 254 are provided within a
first frame element 264. The first frame element 264 together with
the catalysts 254 are mounted within the first section 206 of the
housing 202. In one example, the first bank of catalysts 252
includes eight numbers of the catalysts 254. Alternatively, the
number and a length of the catalysts 254 provided per bank may vary
based on system requirements. The catalysts 254 may include a
circular, oval, elliptical, oblong, or any other cross section,
without limiting the scope of the present disclosure. The first
bank of catalysts 252 may be removably mounted within the first
section 206. Further, the first bank of catalysts 252 may also be
removed for cleaning or replaced as per requirements.
[0027] Further, the first frame element 264 associated with the
first bank of catalysts 252 includes a number of perforations,
namely a first set of perforations 266 and a second set of
perforations 268. The perforations 266, 268 are provided along an
outlet face 270 of the catalysts 258. The perforations 266, 268 may
perform a sound attenuation function and may also reduce back
pressure in the first section 206 of the housing 202. The first and
second set of perforations 266, 268 extend in a direction parallel
to that of the catalysts 254. In one example, the perforations 266,
268 are embodied as through holes, such that the perforations 266,
268 travel along a width of the first frame element 264. The first
set of perforations 266 has a circular shape, and is centrally
disposed on the first frame element 264. Whereas, the second set of
perforations 268 have an approximately semi-circular shape, and are
provided along a periphery of the first frame element 264. Further,
the perforations 266, 268 may have a different shape than that
illustrated in the accompanying figures, based on system
requirements.
[0028] It should be noted that the arrangement of the SCR assembly
250 disclosed herein is exemplary in nature. The arrangement of the
first and second bank of catalysts 252, 256 of the SCR assembly 250
and also the length of each of the catalysts may 254, 258 vary
based on the design of the mixing tube 218 and also the rate of
flow of the exhaust gases.
[0029] Referring to FIG. 2, the modular aftertreatment assembly 200
includes a pair of outlets 272, 274. The outlets 272, 274 are in
fluid communication with the first and third sections 206, 210
respectively. After flowing through the first and second bank of
catalysts 252, 256, the exhaust gases are let out into atmosphere
through the outlets 272, 274. The outlets 272, 274 are provided on
respective top surfaces 276, 278 of the first and third sections
206, 210 of the housing 202 respectively. More particularly, the
outlets 272, 274 are centrally positioned on the top surface 276,
278 of the first and third sections 206, 210. Alternatively, the
positions of the outlets 272, 274 may vary based on system
requirements. The outlets 272, 274 may be embodied as square
apertures or circular apertures. The outlets 272, 274 may be
coupled to a common plenum (not shown) that receives the exhaust
gases exiting the outlets 272, 274. The plenum may in turn be
coupled to a stack arrangement to release the exhaust gases in to
the atmosphere.
INDUSTRIAL APPLICABILITY
[0030] The modular aftertreatment assembly 200 includes a split
flow design. The modular aftertreatment assembly 200 has a compact
design and may be mounted in a small space. Further, the modular
aftertreatment assembly 200 experiences reduced amount of
backpressures owing to its design. The modular aftertreatment
assembly 200 includes a single central inlet end 220 that receives
and introduces the exhaust gases into the mixing tube 218. The
mixing tube 218 includes the slots 226 provided at the outlet end
222. The slots 226 allow the main stream 228 of the exhaust gases
to exit the mixing tube 218 without biasing the first and second
bank of catalysts 252, 256. The slots 226 in the mixing tube 218
reduce space claim requirements due to increased mixing at the
outlet end 222 of the mixing tube 218. The diffusion assembly 240
allows individual tuning of the respective first and second exhaust
gas flows 230, 232 towards each catalyst 254, 258 of the first and
second bank of catalysts 252, 256
[0031] Further, the modular aftertreatment assembly 200 disclosed
herein includes a total of sixteen catalysts 254, 258. More
particularly, instead of providing a single bank of catalyst, the
split flow design includes two banks of catalysts 252, 256 that
each includes equal number of catalysts 254, 258. The provision of
two banks of catalysts 252, 256 leads to the doubling of the
catalyst faces, which in turn reduces the amount of back pressure
experienced by the modular aftertreatment assembly 200. Further,
the perforations 266, 268 provided with respect to the bank of
catalysts 252, 256 perform the sound attenuation function, and also
reduce the back pressure experienced by the SCR assembly 250. The
perforations 266, 268 also reduce the space claim and allow the
design of the modular aftertreatment assembly 200 to be more
compact.
[0032] While aspects of the present disclosure have been
particularly shown and described with reference to the embodiments
above, it will be understood by those skilled in the art that
various additional embodiments may be contemplated by the
modification of the disclosed machines, systems and methods without
departing from the spirit and scope of what is disclosed. Such
embodiments should be understood to fall within the scope of the
present disclosure as determined based upon the claims and any
equivalents thereof.
* * * * *