FIELD OF THE INVENTION
[001] Embodiments of the present application illustrates heat insulation of metal surfaces,
such as exhaust after treatment systems. The invention is also associated to heat shield
arrangement to reduce temperature loss and to lower the fuel consumption during active
regeneration of diesel particulate filter.
BACKGROUND OF THE INVENTION
Background description includes information that may be useful in understanding the present
invention. It is not an admission that any of the information provided herein is prior art or
relevant to the presently disclosed invention, or that any publication specifically or implicitly
referenced is prior art.
[002] In conventional heat shield arrangement, a major portion of underlying surface is
uncovered due to the manufacturing feasibility and welding bead constraints. In view of this,
in the older and conventional arrangements, the uncovered area is left for weld bead between
either 2 heat insulations or between heat insulation and another component. Because of this the
insulation cannot be compressed at edges so the overall insulation thickness is reduced, and the
insulation length is reduced at edges.
[003] As a result of the reduction in insulation thickness and presence of uneven gaps, the
conventional heat shield arrangements face the issue of high heat loss, excessive heating in the
gaps, and this may affect any electrical/electronic wiring that is extended across or proximal to
the surface of the conventional heat shield arrangement and excessive heat loss also leads to
increased supply of fuel to sustain higher temperature inside the substrate to regenerate the
accumulated soot due to engine oil consumption and unburnt hydrocarbons.
[004] Therefore, there is a need for a heat shield arrangement to cover the hot surface such
that the surface temperature requirements are fulfilled with significantly higher efficiency as
compared to prior art heat shields and their respective arrangements.
3
SUMMARY OF THE INVENTION
The following presents a simplified summary of the subject matter in order to provide a basic
understanding of some of the aspects of subject matter embodiments. This summary is not an
extensive overview of the subject matter. It is not intended to identify key/critical elements of
the embodiments or to delineate the scope of the subject matter. Its sole purpose to present
some concepts of the subject matter in a simplified form as a prelude to the more detailed
description that is presented later.
[005] In an embodiment of the present invention, the present invention relates to an exhaust
after-treatment system for reducing temperature loss and lowering the fuel consumption during
active regeneration. The system comprising an inlet flange having a first surface, an inlet pipe
having a second surface and a second heat shield sandwiching a second insulation, an inlet
cone having a third surface and a third heat shield sandwiching a third insulation, a diesel
oxidation catalyst (DOC) shell having a fourth surface and a fourth heat shield sandwiching a
fourth insulation, a diesel particulate filter (DPF) shell having a fifth surface and a fifth heat
shield sandwiching a fifth insulation, an outlet cone having a sixth surface and a sixth heat
shield sandwiching a sixth insulation, an outlet pipe having a seventh surface and a seventh
heat shield sandwiching a seventh insulation, and an outlet flange having an eighth surface.
The inlet flange, the inlet pipe, and the inlet cone are welded in series and are in fluid
communication to receive the exhaust. The outlet cone, the outlet pipe, and the outlet flange
are welded in series and are in fluid communication to exit the exhaust. The inlet cone is
connected to the diesel oxidation catalyst (DOC) shell which is connected to the diesel
particulate filter (DPF) shell which is connected to the outlet cone. The third heat shield
covering the third surface of the inlet cone is welded on the fourth surface of the diesel
oxidation catalyst (DOC) shell such that a portion of the fourth heat shield of the fourth surface
and the third heat shield overlaps.
[006] In an embodiment of the present invention, the second heat shield covering the second
surface of the inlet pipe is welded on the third surface of the inlet cone such that a portion of
the third heat shield of the third surface and the second heat shield overlaps.
4
[007] In an embodiment of the present invention, a clamp is provided between the diesel
oxidation catalyst (DOC) shell and the diesel particulate filter (DPF) shell and between the
diesel particulate filter (DPF) shell and the outlet cone.
[008] In an embodiment of the present invention, the sixth heat shield covering the sixth
surface of the outlet cone is welded on the seventh surface of the outlet pipe such that a portion
of the seventh heat shield of the seventh surface and the sixth heat shield overlaps.
[009] In an embodiment of the present invention, the system has an addon efficiency of 10-
30% due to overlapping of the heat shields.
[0010] In an embodiment of the present invention, the exhaust that is oxidized and free of
particulate matter is transferred to the atmosphere via the series connection of the outlet cone,
the outlet pipe, and the outlet flange.
[0011] In an embodiment of the present invention, the thickness of the second heat shield, third
heat shield, fourth heat shield, fifth heat shield, sixth heat shield and seventh heat shield are
same.
[0012] In an embodiment of the present invention, the thickness of the second heat shield, third
heat shield, fourth heat shield, fifth heat shield, sixth heat shield and seventh heat shield are
different.
[0013] In an embodiment of the present invention, the thickness of the second insulation, third
insulation, fourth insulation, fifth insulation, sixth insulation and seventh insulation is in a
range of 08 mm to 12 mm.
[0014] In yet another embodiment of the present invention, the second heat shield, fourth heat
shield, fifth heat shield and seventh heat shield are compressed in the shape of chamfer on
edges of the second surface, fourth surface, fifth surface and seventh surface respectively.
[0015] In yet another embodiment of the present invention, at least one of the first surface,
second surface, third surface, fourth surface, fifth surface, sixth surface, seventh surface and
eighth surface is a metal surface.
5
[0016] In yet another embodiment of the present invention, at least one of the second heat
shield, third heat shield, fourth heat shield, fifth heat shield, sixth heat shield and seventh heat
shield is non-metallic.
[0017] In yet another embodiment of the present invention, at least one of the first surface,
second surface, third surface, fourth surface, fifth surface, sixth surface, seventh surface and
eighth surface is a cylindrical surface.
[0018] In yet another embodiment of the present invention, at least one of the first surface,
second surface, third surface, fourth surface, fifth surface, sixth surface, seventh surface and
eighth surface is a curved surface.
[0019] In yet another embodiment of the present invention, the first surface, second surface,
third surface, fourth surface, fifth surface, sixth surface, seventh surface and eighth surface
have a temperature in a range of 250ºC - 650ºC.
[0020] In yet another embodiment of the present invention, the insulation thickness on
overlapping of third heat shield and fourth heat shield is in the range of 9-10 mm, wherein the
third insulation is in linear regression and fourth insulation is in linear progression in the
direction T on the overlapping part, wherein the third insulation is in the range of 3-4 mm and
fourth insulation is in the range of 6-7mm while mating, wherein the total insulation thickness
is in the range of 9-10 mm.
[0021] In yet another embodiment of the present invention, the insulation thickness on
overlapping of third heat shield and fourth heat shield is 10 mm, wherein the third insulation is
in linear regression and fourth insulation is in linear progression in the direction T on the
overlapping part, wherein the third heat shield is 3 mm and fourth heat shield is 7mm while
mating.
[0022] In yet another embodiment of the present invention, the inlet pipe is inside the inlet
cone for 5-6 mm for welding.
6
[0023] In yet another embodiment of the present invention, the inlet pipe and the inlet cone are
completely welded without tack welding.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
The following drawings are illustrative of particular examples for enabling systems and
methods of the present disclosure, are descriptive of some of the methods and mechanism, and
are not intended to limit the scope of the invention. The drawings are not to scale (unless so
stated) and are intended for use in conjunction with the explanations in the following detailed
description.
FIGURE 1 shows a portion of conventional prior art arrangement of heat shield, where the heat
shields covering the substrates or joining the substrates with cone have a gap of 10-15 mm.
FIGURE 2 shows a portion of an overlapped heat shield as shown in FIGURE 3, which shows
overlapping portion between covering or joining of substrates, as an embodiment of the present
invention.
FIGURE 3 shows a front perspective view of the exhaust after-treatment system with
overlapped heat shield, as an embodiment of the present invention.
FIGURE 3A shows an outlet pipe section view of FIGURE 3.
FIGURE 3B shows an inlet pipe section view of FIGURE 3.
FIGURE 3C shows a sectional view of inlet cone, diesel oxidation catalyst (DOC) shell, diesel
particulate filter (DPF) shell and outlet cone of FIGURE 3.
FIGURE 3D shows a sectional view of diesel oxidation catalyst (DOC) shell of FIGURE 3.
FIGURE 3E shows an exploded view of the different layers around and surface of the diesel
oxidation catalyst (DOC) shell.
7
FIGURE 4A shows a portion of the overlapped heat shield, showing diesel particulate filter
(DPF) shell insulation thickness gap of 10 mm, as an embodiment of the present invention.
FIGURE 4B shows a portion of the overlapped heat shield, showing insulation thickness on
overlapping heat insulations of 10 mm, as an embodiment of the present invention.
FIGURE 4C shows a portion of the overlapped heat shield as shown in FIGURE 4B, showing
insulation thickness on overlapping heat shield of 10 mm, also showing separation of
7mm+3mm and 5mm+5mm, as an embodiment of the present invention.
FIGURE 4D shows a portion of the overlapped heat insulation, showing insulation thickness
gap on inlet cone of 10.5 mm, as an embodiment of the present invention.
FIGURE 4E shows a side portion of the overlapped heat shield, showing a gap between pipe
heat shield and cone heat shield, as an embodiment of the present invention.
FIGURES 5A-5G show front view, a side right view, a rear view, a side left view, a top view,
a bottom view, and an isometric view respectively, of the overlapped heat shield, as
embodiments of the present invention.
Persons skilled in the art will appreciate that elements in the figures are illustrated for simplicity
and clarity and may represent both hardware and software components of the system. Further,
the dimensions of some of the elements in the figure may be exaggerated relative to other
elements to help to improve understanding of various exemplary embodiments of the present
disclosure. Throughout the drawings, it should be noted that like reference numbers are used
to depict the same or similar elements, features, and structures.
DETAILED DESCRIPTION OF THE INVENTION
Exemplary embodiments now will be described. The disclosure may, however, be embodied
in many different forms and should not be construed as limited to the embodiments set forth
herein; rather, these embodiments are provided so that this disclosure will be thorough and
complete, and will fully convey its scope to those skilled in the art. The terminology used in
the detailed description of the particular exemplary embodiments illustrated in the
8
accompanying drawings is not intended to be limiting. In the drawings, like numbers refer to
like elements.
It is to be noted, however, that the reference numerals used herein illustrate only typical
embodiments of the present subject matter, and are therefore, not to be considered for limiting
of its scope, for the subject matter may admit to other equally effective embodiments.
The specification may refer to “an”, “one” or “some” embodiment(s) in several locations. This
does not necessarily imply that each such reference is to the same embodiment(s), or that the
feature only applies to a single embodiment. Single features of different embodiments may also
be combined to provide other embodiments.
As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms
as well, unless expressly stated otherwise. It will be further understood that the terms
“includes”, “comprises”, “including” and/or “comprising” when used in this specification,
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. It will be understood
that when an element is referred to as being “connected” or “coupled” to another element, it
can be directly connected or coupled to the other element or intervening elements may be
present. Furthermore, “connected” or “coupled” as used herein may include operatively
connected or coupled. As used herein, the term “and/or” includes any and all combinations and
arrangements of one or more of the associated listed items.
Unless otherwise defined, all terms (including technical and scientific terms) used herein have
the same meaning as commonly understood by one of ordinary skill in the art to which this
disclosure pertains. It will be further understood that terms, such as those defined in commonly
used dictionaries, should be interpreted as having a meaning that is consistent with their
meaning in the context of the relevant art and will not be interpreted in an idealized or overly
formal sense unless expressly so defined herein.
[0024] An arrangement of overlapped heat shield, as disclosed herein, covers the hot surface
such that the surface temperature requirements are fulfilled with efficiency significantly higher
than the conventional heat shield arrangement where a key portion of underlying surface is
9
exposed due to the engineering practicability and welding bead constraints. The innovation in
the arrangement of heat shield is an improvement over conventional arrangements where
exposed area is left for weld bead between either 2 heat shields or between heat shield and
another component. Hence, resulting in a reduced shield thickness and reduced shield length
at the edges. However, in the overlapped heat shield, as disclosed herein, the shield thickness
is not reduced, and shield is chamfered on edges instead of reducing overall thickness and there
is no uncovered area for weld bead as one heat shield overlaps another, and the chamfered
shield is compensated with the insulation thickness of overlapping heat shield such that the
overall insulation thickness remains same.
[0025] The overlapped heat shield in the present invention provides lower surface temperature
especially on the edges and contains the inner surface temperature i.e., the temperature loss is
less and fuel consumption during regeneration is reduced. It solves the problem of higher
temperature loss and more fuel consumption during active regeneration in exhaust aftertreatment system.
[0026] The overlapped heat shield arrangement in the present invention is also used to insulate
any metal surface, specifically cylindrical metal surfaces, for example, exhaust after-treatment
system especially in turbocharged intercooled engines where engine out temperature is in range
or 250-400ºC and continuous passive regeneration along with controlled active regeneration is
required where sustained temperature of 600 ºC is required for soot regeneration. The present
invention with the shield arrangement as disclosed herewith has been both simulated and tested
and the test data is available along with the boundary conditions showing improved results.
[0027] FIGURE. 1 shows a portion of conventional prior art arrangement of heat shield, where
the heat shields covering the substrates or joining the substrates with cone have a gap of 10-15
mm. Based on the heat shield arrangement shown in FIGURE 1, the exposed area is left for
weld bead between either 2 heat shields or between heat shield and another component. Hence,
resulting in a reduced shield thickness and reduced shield length at the edges, which affects the
heat insulating capacity.
[0028] FIGURE. 2 shows a portion of an overlapped heat shield as shown in FIGURE 3, which
shows overlapping portion between covering or joining of substrates, as an embodiment of the
present invention. In order to counter the issues in heat insulating capacity as discussed in
10
FIGURE 1, when the multi-layered insulation is reduced at the edges, the proportional
thickness of insulation is added on the overlapping heat shield. So, the heat stored inside the
exhaust after-treatment system does not escape and the trapped heat helps in continuous passive
regeneration and controlled active regeneration.
[0029] In an embodiment of the present invention, the engine exhaust gas at high temperatures
(400℃ - 550℃) enters the inlet cone (110) and flows through the diesel oxidation catalyst
(DOC) shell (114). During post injection process, higher temperatures are observed after the
diesel oxidation catalyst (DOC) due to the exotherm generated. The excess heat delta is
dissipated at a perceptible high rate especially from the welding joints between inlet cone (110)
and diesel oxidation catalyst (DOC) shell (114). The overlapped heat insulation of the present
invention with overall insulation thickness being alike will keep in-check the heat loss at
mating parts and weld joints.
[0030] FIGURE. 3 shows a front perspective view of the overlapped heat shield. It shows an
inlet flange (102), an inlet pipe (106), an inlet cone (110), a diesel oxidation catalyst (DOC)
shell (114), a diesel particulate filter (DPF) shell (118), an outlet cone (122), an outlet pipe
(126), and an outlet flange (130). The inlet flange (102), inlet pipe (106), and inlet cone (110)
are welded in series and are in fluid communication to receive the exhaust. The diesel oxidation
catalyst (DOC) reduces the volume of carbon monoxide (CO) and hydrocarbons (HC) in the
exhaust gas by oxidizing them to carbon dioxide and water at high temperature. The oxidized
exhaust is transferred to the diesel particulate filter (DPF) shell (118) that removes diesel
particulate matter or soot from the exhaust gas. The exhaust that is oxidized and free of
particulate matter is further transferred to the atmosphere via the series connection of the outlet
cone (122), the outlet pipe (126), and the outlet flange (130).
[0031] The area of interest with respect to the present invention is, for example, the overlapped
portion between the diesel oxidation catalyst (DOC) shell (114) and the inlet cone (110). Here,
the edges have a reduced amount of the multi-layered insulation, and therefore, there is an
addition of a proportional thickness of insulation on the overlapping heat shield. This prevents
the heat stored inside the exhaust system from escaping and traps the heat within, which assists
in two primary aspects, namely continuous passive regeneration and controlled active
regeneration.
11
[0032] In accordance with an embodiment of the present invention, as maximum heat loss is
at inlet cone (110) & diesel oxidation catalyst (DOC) shell (114) inlet, the overlapped heat
shield specifically prevents this heat loss as the inlet cone (110) heat shield is welded on the
diesel oxidation catalyst (DOC) shell (114) heat shield instead of inlet cone (110) itself as it is
in convention heat shield arrangement. Instead of having 10-15 mm gap between diesel
oxidation catalyst (DOC) shell heat shield and inlet cone heat shield where the diesel oxidation
catalyst (DOC) shell heat shield is welded on diesel oxidation catalyst (DOC) shell and inlet
cone heat shield welded on inlet cone, in overlapped heat shield, the diesel oxidation catalyst
(DOC) shell (114) heat shield is similar to conventional heat shield where it is welded on diesel
oxidation catalyst (DOC) shell (114) but inlet cone (110) heat shield is welded on diesel
oxidation catalyst (DOC) shell (114) heat shield so that the reduction in heat shield thickness
of diesel oxidation catalyst (DOC) shell (114) heat insulation is compensated with inlet cone
(110) heat shield.
[0033] The gap of 10-15 mm that is provided between 2 heat shields gets consumed in weld
beads of both the heat shields but in the overlapped heat shield arrangement, as the inlet cone
(110) heat shield is the welded on the diesel oxidation catalyst (DOC) shell (114) heat shield,
so the space required for weld bead of inlet cone (110) heat shield is taken from the diesel
oxidation catalyst (DOC) shell (114) heat shield & the minimum gap requirement constraint is
eliminated.
[0034] FIGURE 3A shows an outlet pipe (106) section view of FIGURE 3 showing an outlet
pipe (126) having a seventh surface (128) and a seventh heat shield (127) sandwiching a
seventh insulation (127a), and an outlet flange (130) having an eighth surface (132).
[0035] FIGURE 3B shows an inlet pipe (126) section view of FIGURE 3 showing an inlet
flange (102) having a first surface (104), an inlet pipe (106) having a second surface (108) and
a second heat shield (109) sandwiching a second insulation (109a).
[0036] FIGURE 3C shows a sectional view of inlet cone (110), diesel oxidation catalyst (DOC)
shell (114), diesel particulate filter (DPF) shell (118) and outlet cone (122) of FIGURE 3
showing an inlet cone (110) having a third surface (112) and a third heat shield (111)
sandwiching a third insulation (111a), a diesel oxidation catalyst (DOC) shell (114) having a
fourth surface (116) and a fourth heat shield (115) sandwiching a fourth insulation (115a), a
12
diesel particulate filter (DPF) shell (118) having a fifth surface (120) and a fifth heat shield
(119) sandwiching a fifth insulation (119a), an outlet cone (122) having a sixth surface (124)
and a sixth heat shield (123) sandwiching a sixth insulation (123a).
[0037] FIGURE 3D shows a sectional view of diesel oxidation catalyst (DOC) shell (114) of
FIGURE 3 showing a diesel oxidation catalyst (DOC) shell (114) having a fourth surface (116)
and a fourth heat shield (115) sandwiching a fourth insulation (115a).
[0038] FIGURE 3E shows an exploded view of the different layers around and surface of the
diesel oxidation catalyst (DOC) shell (114) representing a diesel oxidation catalyst (DOC) shell
(114) having a fourth surface (116) and a fourth heat shield (115) sandwiching a fourth
insulation (115a).
[0039] Referring to FIGURES 4A-4D, FIGURE 4A shows a portion of the overlapped heat
shield, showing diesel particulate filter (DPF) shell (118) insulation thickness gap of 10 mm,
as an embodiment of the present invention. FIGURE 4B shows a portion of the overlapped heat
shield, showing insulation thickness on overlapping heat shields of 10 mm, as an embodiment
of the present invention. FIGURE 4C shows a portion of the overlapped heat shield as shown
in FIGURE 4B, showing insulation thickness on overlapping heat shields of 10 mm, also
showing separation of 7mm+3mm and 5mm+5mm, as an embodiment of the present invention.
FIGURE 4D shows a portion of the overlapped heat shield, showing insulation thickness gap
on inlet cone of 10.5 mm, as an embodiment of the present invention.
[0040] As shown in the FIGURES 4A-4D, the overall insulation thickness is maintained on
complete assembly as 10 mm by overlapping adjacent heat shield. By arranging this way, the
reduction in gap of a heat shield is compensated by other overlapping heat shield, whereas in
other arrangements, insulation thickness reduces at the edges due to weld joint requirement.
Furthermore, due to overlapping, the insulation thickness on inlet cone is further increased to
11 mm. As the major heat loss takes place from inlet side, increased insulation thickness due
to overlapping further reduces the heat loss and reduces fuel consumption by reducing the
interval of active regeneration.
[0041] In an embodiment of the present invention, during the active regeneration of a Diesel
particulate filter (DPF), the post injection process soar the hydrocarbon slip from engine which
13
enter diesel oxidation catalyst (DOC) shell (114), wherein its oxidation occurs, creating a
temperature exotherm. Increased temperature facilitates oxidation of the deposited C-soot
particles on the upstream Diesel particulate filter (DPF). This process (called active
regeneration) requires highly insulated chamber aiming to prevent the generated heat would
not escape the regeneration environment else post injection numbers will rise thereby
increasing the fuel consumption.
[0042] In the conventional heat shield arrangement, the gap between 2 heat shields covering
either 2 substrates or substrate or cone has to be kept 10-15 mm to accommodate the weld bead
nut. In the overlapped heat shield arrangement of the present invention, when the insulation
thickness gets reduced due to heat shield joint on shell or cone, another heat shield with the
proportional insulation thickness overlaps the existing heat shield and the overall insulation
thickness remains same.
[0043] FIGURE 4E shows a side portion of the overlapped heat shield, showing a gap between
pipe heat shield and cone heat shield, as an embodiment of the present invention. In a
conventional arrangement, the gap between 2 heat shields is 10-15 mm as the weld bead of
single heat shield takes 5 mm, therefore, a 10-15 mm gap (where overlapping is not possible)
is required. However, in the arrangement of the present invention, the gap between 2 heat
shields is 6-7 mm so that the heat trapping efficiency is not affected. This gap is achieved
through welding both the heat shields with a single tack i.e., with a weld bead of 4 mm, and
hence both the heat shields can be welded.
BEST MODE OF WORKING THE INVENTION
[0044] In accordance with an embodiment of the present invention, the present
invention discloses an exhaust after-treatment system for reducing temperature loss and lowering
the fuel consumption during active regeneration as shown in Figures 3-3E viewed simultaneously,
comprising an inlet flange (102) having a first surface (104), an inlet pipe (106) having a second
surface (108) and a second heat shield (109) sandwiching a second insulation (109a), an inlet
cone (110) having a third surface (112) and a third heat shield (111) sandwiching a third
insulation (111a), a diesel oxidation catalyst (DOC) shell (114) having a fourth surface (116)
and a fourth heat shield (115) sandwiching a fourth insulation (115a), a diesel particulate filter
(DPF) shell (118) having a fifth surface (120) and a fifth heat shield (119) sandwiching a fifth
14
insulation (119a), an outlet cone (122) having a sixth surface (124) and a sixth heat shield (123)
sandwiching a sixth insulation (123a), an outlet pipe (126) having a seventh surface (128) and
a seventh heat shield (127) sandwiching a seventh insulation (127a), and an outlet flange (130)
having an eighth surface (132). The inlet flange (102), the inlet pipe (106), and the inlet cone
(110) are welded in series and are in fluid communication to receive the exhaust. The outlet
cone (122), the outlet pipe (126), and the outlet flange (130) are welded in series and are in
fluid communication to exit the exhaust. The inlet cone (110) is connected to the diesel
oxidation catalyst (DOC) shell (114) which is connected to the diesel particulate filter (DPF)
shell (118) which is connected to the outlet cone (122). The third heat shield (111) covering
the third surface (112) of the inlet cone (110) is welded on the fourth surface (116) of the diesel
oxidation catalyst (DOC) shell (114) such that a portion of the fourth heat shield (115) of the
fourth surface (116) and the third heat shield (111) overlaps as shown in Figure 4C.
[0045] In a specific example, the second heat shield (109) covering the second surface (108)
of the inlet pipe (106) is welded on the third surface (112) of the inlet cone (110) such that a
portion of the third heat shield (111) of the third surface (112) and the second heat shield (109)
overlaps.
[0046] In a specific example, a clamp is provided between the diesel oxidation catalyst (DOC)
shell (114) and the diesel particulate filter (DPF) shell (118) and between the diesel particulate
filter (DPF) shell (118) and the outlet cone (122).
[0047] In a specific example, the sixth heat shield (123) covering the sixth surface (124) of the
outlet cone (122) is welded on the seventh surface (128) of the outlet pipe (126) such that a
portion of the seventh heat shield (127) of the seventh surface (128) and the sixth heat shield
(123) overlaps.
[0048] In a specific example, the system has an addon efficiency of 10-30% due to overlapping
of the heat shields.
[0049] In a specific example, the exhaust that is oxidized and free of particulate matter is
transferred to the atmosphere via the series connection of the outlet cone (122), the outlet pipe
(126), and the outlet flange (130).
15
[0050] In another specific example, the thickness of the second heat shield (109), third heat
shield (111), fourth heat shield (115), fifth heat shield (119), sixth heat shield (123) and seventh
heat shield (127) are same.
[0051] In another specific example, the thickness of the second heat shield (109), third heat
shield (111), fourth heat shield (115), fifth heat shield (119), sixth heat shield (123) and seventh
heat shield (127) are different.
[0052] In another specific example, the thickness of the second insulation (109a), third
insulation (111a), fourth insulation (115a), fifth insulation (119a), sixth insulation (123a) and
seventh insulation (127a) is in a range of 08 mm to 12 mm.
[0053] In another specific example, the second heat shield (109), fourth heat shield (115), fifth
heat shield (119) and seventh heat shield (127) are compressed in the shape of chamfer on
edges of the second surface (108), fourth surface (116), fifth surface (120) and seventh surface
(128) respectively.
[0054] In another specific example, at least one of the first surface (104), second surface (108),
third surface (112), fourth surface (116), fifth surface (120), sixth surface (124), seventh surface
(128) and eighth surface (132) is a metal surface.
[0055] In yet another specific example, at least one of the second heat shield (109), third heat
shield (111), fourth heat shield (115), fifth heat shield (119), sixth heat shield (123) and seventh
heat shield (127) is non-metallic.
[0056] In yet another specific example, at least one of the first surface (104), second surface
(108), third surface (112), fourth surface (116), fifth surface (120), sixth surface (124), seventh
surface (128) and eighth surface (132) is a cylindrical surface.
[0057] In yet another specific example, at least one of the first surface (104), second surface
(108), third surface (112), fourth surface (116), fifth surface (120), sixth surface (124), seventh
surface (128) and eighth surface (132) is a curved surface.
16
[0058] In yet another specific example, the first surface (104), second surface (108), third
surface (112), fourth surface (116), fifth surface (120), sixth surface (124), seventh surface
(128) and eighth surface (132) have a temperature in a range of 250ºC - 650ºC.
[0059] In yet another specific example, the insulation thickness on overlapping of third heat
shield (111) and fourth heat shield (115) is in the range of 9-10 mm, wherein the third insulation
(111a) is in linear regression and fourth insulation (115a) is in linear progression in the
direction T on the overlapping part, wherein the third insulation (111a) is in the range of 3-4
mm and fourth insulation (115a) is in the range of 6-7mm while mating, wherein the total
insulation thickness is in the range of 9-10 mm.
[0060] In yet another specific example, the insulation thickness on overlapping of third heat
shield (111) and fourth heat shield (115) is 10 mm, wherein the third insulation (111a) is in
linear regression and fourth insulation (115a) is in linear progression in the direction T on the
overlapping part, wherein the third heat shield (111) is 3 mm and fourth heat shield (115) is
7mm while mating.
[0061] In yet another specific example, the inlet pipe (106) is inside the inlet cone (110) for 5-
6 mm for welding.
[0062] In yet another specific example, the inlet pipe (106) and the inlet cone (110) are
completely welded without tack welding.
TEST RESULTS/ COMPARATIVE DATA
17
[0063] FIGURES 5A-5G show front a view, a side right view, a rear view, a side left view, a
top view, a bottom view, and an isometric view respectively, of the overlapped heat shield, as
embodiments of the present invention. FIGURES 5A-5G show the area covered by heat
insulation to ensure complete area coverage for retaining heat and protecting peripheral parts.
[0064] The present invention has an advantage that it provides a uniform insulation thickness
throughout the geometry for better temperature control, in conventional arrangement, thickness
at the end of the heat shield is reduced resulting in high temperature in those regions. The
present invention helps to avoid such high temperature zones and maintains uniform
thickness/temperature throughout the geometry.
Although the invention has been described with reference to specific embodiments, this
description is not meant to be construed in a limiting sense. Various modifications of the
disclosed embodiments, as well as alternate embodiments of the invention, will become
apparent to persons skilled in the art upon reference to the description of the invention. It is
therefore, contemplated that such modifications can be made without departing from the scope
of the present invention as defined.
18
REFERENCE NUMERALS
Inlet flange - 102
First surface - 104
Inlet pipe - 106
Second surface - 108
Second heat shield - 109
Second insulation - 109a
Inlet cone - 110
Third heat shield - 111
Third insulation - 111a
Third surface - 112
Diesel oxidation catalyst (DOC) shell - 114
Fourth heat shield - 115
Fourth insulation - 115a
Fourth surface - 116
Diesel Particulate Filter (DPF) shell - 118
Fifth heat shield - 119
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Fifth insulation - 119a
Fifth surface - 120
Outlet cone - 122
Sixth heat shield - 123
Sixth insulation - 123a
Sixth surface - 124
Outlet pipe - 126
Seventh heat shield - 127
Seventh insulation - 127a
Seventh surface - 128
Outlet flange - 130
Eighth surface - 132

We Claim:
1. An exhaust after-treatment system for reducing temperature loss and lowering the fuel
consumption during active regeneration comprising:
an inlet flange (102) having a first surface (104), an inlet pipe (106) having a second
surface (108) and a second heat shield (109) sandwiching a second insulation (109a), an
inlet cone (110) having a third surface (112) and a third heat shield (111) sandwiching a
third insulation (111a), a diesel oxidation catalyst (DOC) shell (114) having a fourth
surface (116) and a fourth heat shield (115) sandwiching a fourth insulation (115a), a
diesel particulate filter (DPF) shell (118) having a fifth surface (120) and a fifth heat shield
(119) sandwiching a fifth insulation (119a), an outlet cone (122) having a sixth surface
(124) and a sixth heat shield (123) sandwiching a sixth insulation (123a), an outlet pipe
(126) having a seventh surface (128) and a seventh heat shield (127) sandwiching a
seventh insulation (127a), and an outlet flange (130) having an eighth surface (132);
the inlet flange (102), the inlet pipe (106), and the inlet cone (110) are welded in series
and are in fluid communication to receive the exhaust;
the outlet cone (122), the outlet pipe (126), and the outlet flange (130) are welded in
series and are in fluid communication to exit the exhaust;
the inlet cone (110) is connected to the diesel oxidation catalyst (DOC) shell (114)
which is connected to the diesel particulate filter (DPF) shell (118) which is connected to
the outlet cone (122); and
wherein the third heat shield (111) covering the third surface (112) of the inlet cone
(110) is welded on the fourth surface (116) of the diesel oxidation catalyst (DOC) shell
(114) such that a portion of the fourth heat shield (115) of the fourth surface (116) and the
third heat shield (111) overlaps.
2. The exhaust after-treatment system as claimed in claim 1, wherein the second heat shield
(109) covering the second surface (108) of the inlet pipe (106) is welded on the third
surface (112) of the inlet cone (110) such that a portion of the third heat shield (111) of
the third surface (112) and the second heat shield (109) overlaps.
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3. The exhaust after-treatment system as claimed in claim 1, wherein a clamp is provided
between the diesel oxidation catalyst (DOC) shell (114) and the diesel particulate filter
(DPF) shell (118) and between the diesel particulate filter (DPF) shell (118) and the outlet
cone (122).
4. The exhaust after-treatment system as claimed in claim 1, wherein the sixth heat shield
(123) covering the sixth surface (124) of the outlet cone (122) is welded on the seventh
surface (128) of the outlet pipe (126) such that a portion of the seventh heat shield (127)
of the seventh surface (128) and the sixth heat shield (123) overlaps.
5. The exhaust after-treatment system as claimed in claims 1 to 4, wherein the system has an
addon efficiency of 10-30% due to overlapping of the heat shields.
6. The exhaust after-treatment system as claimed in claim 1, wherein the exhaust that is
oxidized and free of particulate matter is transferred to the atmosphere via the series
connection of the outlet cone (122), the outlet pipe (126), and the outlet flange (130).
7. The exhaust after-treatment system as claimed in claim 1, wherein the thickness of the
second heat shield (109), third heat shield (111), fourth heat shield (115), fifth heat shield
(119), sixth heat shield (123) and seventh heat shield (127) are same.
8. The exhaust after-treatment system as claimed in claim 1, wherein the thickness of the
second heat shield (109), third heat shield (111), fourth heat shield (115), fifth heat shield
(119), sixth heat shield (123) and seventh heat shield (127) are different.
9. The exhaust after-treatment system as claimed in claim 1, wherein the thickness of the
second insulation (109a), third insulation (111a), fourth insulation (115a), fifth insulation
(119a), sixth insulation (123a) and seventh insulation (127a) is in a range of 08 mm to 12
mm.
10. The exhaust after-treatment system as claimed in claim 1, wherein the second heat shield
(109), fourth heat shield (115), fifth heat shield (119) and seventh heat shield (127) are
compressed in the shape of chamfer on edges of the second surface (108), fourth surface
(116), fifth surface (120) and seventh surface (128) respectively.
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11. The exhaust after-treatment system as claimed in claim 1, wherein at least one of the first
surface (104), second surface (108), third surface (112), fourth surface (116), fifth surface
(120), sixth surface (124), seventh surface (128) and eighth surface (132) is a metal
surface.
12. The exhaust after-treatment system as claimed in claim 1, wherein at least one of the second
heat shield (109), third heat shield (111), fourth heat shield (115), fifth heat shield (119),
sixth heat shield (123) and seventh heat shield (127) is non-metallic.
13. The exhaust after-treatment system as claimed in claim 1, wherein at least one of the first
surface (104), second surface (108), third surface (112), fourth surface (116), fifth surface
(120), sixth surface (124), seventh surface (128) and eighth surface (132) is a cylindrical
surface.
14. The exhaust after-treatment system as claimed in claim 1, wherein at least one of the first
surface (104), second surface (108), third surface (112), fourth surface (116), fifth surface
(120), sixth surface (124), seventh surface (128) and eighth surface (132) is a curved
surface.
15. The exhaust after-treatment system as claimed in claim 1, wherein the first surface (104),
second surface (108), third surface (112), fourth surface (116), fifth surface (120), sixth
surface (124), seventh surface (128) and eighth surface (132) have a temperature in a range
of 250ºC - 650ºC.
16. The exhaust after-treatment system as claimed in claim 1, wherein the insulation thickness
on overlapping of third heat shield (111) and fourth heat shield (115) is in the range of 9-
10 mm, wherein the third insulation (111a) is in linear regression and fourth insulation
(115a) is in linear progression in the direction T on the overlapping part, wherein the third
insulation (111a) is in the range of 3-4 mm and fourth insulation (115a) is in the range of
6-7mm while mating, wherein the total insulation thickness is in the range of 9-10 mm.
17. The exhaust after-treatment system as claimed in claim 1, wherein the insulation thickness
on overlapping of third heat shield (111) and fourth heat shield (115) is 10 mm, wherein
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the third insulation (111a) is in linear regression and fourth insulation (115a) is in linear
progression in the direction T on the overlapping part, wherein the third heat shield (111)
is 3 mm and fourth heat shield (115) is 7mm while mating.
18. The exhaust after-treatment system as claimed in claim 1, wherein the inlet pipe (106) is
inside the inlet cone (110) for 5-6 mm for welding.
19. The exhaust after-treatment system as claimed in claim 1, wherein the inlet pipe (106) and
the inlet cone (110) are completely welded without tack welding.