U.S. patent application number 12/701094 was filed with the patent office on 2011-08-11 for exhaust after treatment assembly.
Invention is credited to Keith Jonathan Schmidt.
Application Number | 20110192153 12/701094 |
Document ID | / |
Family ID | 44352599 |
Filed Date | 2011-08-11 |
United States Patent
Application |
20110192153 |
Kind Code |
A1 |
Schmidt; Keith Jonathan |
August 11, 2011 |
EXHAUST AFTER TREATMENT ASSEMBLY
Abstract
The invention relates to an exhaust after treatment assembly.
There is a need for such assembly which remains as cool as
possible. An exhaust after treatment assembly includes a hollow
housing containing an exhaust after treatment unit. The housing
forms a nozzle which directs exhaust gases away from the after
treatment unit. A shield surrounds and is spaced apart from the
housing. A venturi unit receives exhaust gases from the nozzle and
receives outside air. The venturi unit pulls outside air over an
exterior of the shield and mixes the outside air with exhaust gases
flowing though the after treatment unit. The venturi unit is
mounted inside a hood which surrounds part of the housing. Outside
air is drawn through an annular gap which is formed between an end
of the hood and an end of the shield.
Inventors: |
Schmidt; Keith Jonathan;
(Cedar Falls, IA) |
Family ID: |
44352599 |
Appl. No.: |
12/701094 |
Filed: |
February 5, 2010 |
Current U.S.
Class: |
60/317 |
Current CPC
Class: |
F01N 3/05 20130101; Y02T
10/20 20130101; Y02T 10/12 20130101; F01N 2590/08 20130101; F01N
13/20 20130101 |
Class at
Publication: |
60/317 |
International
Class: |
F01N 3/05 20060101
F01N003/05 |
Claims
1. An exhaust after treatment assembly, comprising: a hollow
housing containing an exhaust after treatment unit; a nozzle for
directing exhaust gases away from the after treatment unit; a
shield surrounding and spaced apart from the housing; and a venturi
unit receiving exhaust gases from the nozzle and receiving outside
air, the venturi unit operating to pull outside air over an
exterior of the shield and to mix said outside air with exhaust
gases flowing though the after treatment unit.
2. The exhaust after treatment assembly of claim 1, further
comprising: a hood having an inlet end, an outlet end and a tubular
portion connecting the inlet end to the outlet end, the venturi
unit being mounted inside the tubular portion, the inlet end being
spaced apart from and surrounding an end of the shield and forming
an annular gap therebetween, the venturi unit drawing outside air
through said gap.
3. The exhaust after treatment assembly of claim 2, wherein: the
hood comprises a tapered portion connected between the inlet end
and the tubular portion.
4. The exhaust after treatment assembly of claim 1, wherein: the
housing includes a main portion surrounding the after treatment
unit and a conical portion connecting the main portion to the
nozzle.
5. The exhaust after treatment assembly of claim 1, wherein: the
venturi unit comprises a larger diameter entry surrounding a
downstream end of the nozzle, a smaller diameter neck downstream of
the entry and a larger diameter exit downstream of the neck.
6. An exhaust after treatment assembly, comprising: a hollow
housing having a central portion containing an exhaust after
treatment unit, an inlet end for communicating engine exhaust gases
to the after treatment unit and having an outlet for directing
exhaust gases away from the after treatment unit, the outlet having
a nozzle and a conical portion connecting the nozzle to an end of
the central portion; a shield surrounding and spaced apart from the
central portion of the housing; and a hood having an inlet end
surrounding a downstream end of the shield, a tapered portion
connected to the inlet end and surrounding the conical portion and
the nozzle, a tubular portion connected to a downstream end of the
tapered portion and extending to an outlet remote from the tapered
portion; and the tubular portion having a venturi unit therein, the
venturi unit having a larger diameter entry surrounding a
downstream end of the nozzle, a smaller diameter neck downstream of
the entry and a larger diameter exit downstream of the neck, the
venturi operating to pull outside air over an exterior of the
shield, over the an exterior of the conical portion and the nozzle
and to mix said outside air with exhaust gases flowing though the
after treatment unit.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to an exhaust after treatment
assembly for an internal combustion engine.
BACKGROUND OF THE INVENTION
[0002] An exhaust treatment component arrangement for an off-road
vehicle such as an agricultural tractor is described in U.S. patent
application Ser. No. 11/654,203 filed on 16 Jan. 2007 and assigned
to the assignee of the present application. This exhaust treatment
component arrangement is intended to meet Tier 4 interim emissions
standards, which will require all off-highway vehicles to manage
Particulate Matter (PM) and NOx levels. This exhaust treatment
component arrangement includes exhaust after treatment devices,
such as both a diesel particulate filter (PDF) and a Diesel
Oxidation Catalyst (DOC).
[0003] A regeneration process is used with exhaust after treatment
devices, wherein soot and particulate matter is burned off and
temperatures inside the devices can reach 630 degrees C.
Additionally, some of the after treatment device skin temperatures
in certain areas can reach temperatures higher than desired. During
vehicle operation, and especially during regeneration of such after
treatment devices, it is desired to limit the heating of such an
exhaust after treatment device.
SUMMARY
[0004] Accordingly, an object of this invention is to provide an
exhaust after treatment assembly which cools exhaust air which
flows therethrough.
[0005] A further object of the invention is to provide such an
exhaust after treatment assembly which cools the exhaust after
treatment components.
[0006] These and other objects are achieved by the present
invention, wherein an exhaust after treatment assembly includes a
hollow housing containing at least one exhaust after treatment
unit. The housing forms a nozzle for directing exhaust gases away
from the after treatment unit. A shield surrounds and is spaced
apart from the housing. A venturi unit receives exhaust gases from
the nozzle and receives outside air. A hood has an inlet end, an
outlet end and a tubular portion connecting the inlet end to the
outlet end. The venturi unit is mounted inside the tubular portion.
The inlet end is spaced apart from and surrounds an end of the
shield and forms an annular gap therebetween. The venturi unit
draws outside air through the gap, pulls outside air over an
exterior of the shield, and mixes the outside air with exhaust
gases which have flowed though the after treatment units.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 is a sectional side view of an exhaust after
treatment assembly embodying the invention;
[0008] FIG. 2 is a perspective view of the exhaust after treatment
assembly of FIG. 1; and
[0009] FIG. 3 is a sectional view along lines 3-3 of FIG. 1.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0010] Referring to FIGS. 1 and 2, an exhaust after treatment
assembly 10 includes a hollow housing 12 which has a cylindrical
main portion 14 which contains exhaust after treatment units, such
as a diesel oxidation catalyst (DOC) 16 and diesel particulate
filter (DPF) 18. Housing 12 has an inlet end 20 which receives
engine exhaust gases from an exhaust pipe 21 which is connected to
a source of exhaust gases, such as a diesel engine (not shown). The
inlet end 20 communicates exhaust gases to the after treatment
units 16 and 18. Housing 12 also includes an outlet 22 for
directing exhaust gases away from the after treatment units 16 and
18. The outlet 22 includes a nozzle 24 and a conical portion 26
which connects the nozzle 24 to an end of the main portion 14.
[0011] As best seen in FIG. 1, circular band clamps 27 and 28 are
mounted around and on the housing 12. A plurality of brackets 29
are attached to the clamps 27 and 28. Brackets 29 support a hollow
cylindrical shield 30 which surrounds and is spaced apart from the
housing 12. As best seen in FIGS. 1 and 3, an additional circular
band clamp 32 is mounted around the upper end of the housing 12. A
plurality of brackets 34 are attached to the clamp 32. Brackets 34
support a hollow hood 40.
[0012] The hood 40 has a larger diameter inlet end 42 which is
adjacent to and spaced apart from a downstream end of the shield
30, forming an annular gap 43 therebetween. The hood 40 also
includes a tapered portion 44 which is connected to the inlet end
42 and which surrounds the conical portion 26 and the nozzle 24 of
the housing 12. The hood 40 also includes a tubular portion or
exhaust pipe 46 which is connected to a downstream end of the
tapered portion 44 and extends to an outlet 48 remote from the
tapered portion 44.
[0013] The tubular portion 44 has a venturi unit 50 therein. The
venturi unit 50 has a larger diameter entry 52 which surrounds and
is spaced apart from a downstream end of the nozzle 24, a smaller
diameter neck 54 downstream of the entry 52, and a larger diameter
exit 54 downstream of the neck 54.
[0014] As hot exhaust gases flow through the units 16 and 18, out
of the nozzle 24 and through the venturi 50, the increased velocity
of the exhaust gases creates a pressure drop which pulls outside
air into the gap 43 and through the space between the tapered
portion 44 of the hood 40 and into the venturi 50. In the venturi
50 this outside air mixes with and cools the exhaust gases. This
outside air is also pulled over an exterior of the shield 30, and
over the exterior of the conical portion 26 and the nozzle 24, and
provides a cooling effect thereon.
[0015] As best seen in FIG. 3, a circular clamp 52 is mounted on
the upper end of the shield 30, and a plurality of
[0016] The hood 40 is preferably made out of steel which is deep
drawn or spun to achieve the desired shape. The hood 40 has a bell
shape which closely matches the shape of the conical portion 26 and
the nozzle 24 of the housing 14 in order to maximize airflow
(minimum resistance) and to achieve the desired air volume,
pressure, and velocities which optimize resulting exhaust gas
temperature.
[0017] With this design hot exhaust gases exiting the after
treatment units 16 and 18 are cooled down to desired temperatures
as measured at varying distance from the exhaust pipe outlet. The
hood 40 also acts as a shield to protect the top of the housing 14
and keeps debris off of the surfaces thereof. Thirdly, the cool air
drawn in at the bottom of the hood 40 passes by the top surface of
the conical portion 26 and the nozzle 24, reducing their skin
temperatures.
[0018] While the present invention has been described in
conjunction with a specific embodiment, it is understood that many
alternatives, modifications and variations will be apparent to
those skilled in the art in light of the foregoing description.
[0019] Accordingly, this invention is intended to embrace all such
alternatives, modifications and variations which fall within the
spirit and scope of the appended claims.
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