U.S. patent application number 13/753660 was filed with the patent office on 2014-07-31 for air shielded water cooled exhaust manifold with exhaust tube support.
This patent application is currently assigned to CATERPILLAR, INC.. The applicant listed for this patent is CATERPILLAR, INC.. Invention is credited to Daniel Richard Barb, MD Anwarul Karim, Robert A. Sarsfield.
Application Number | 20140208726 13/753660 |
Document ID | / |
Family ID | 51163621 |
Filed Date | 2014-07-31 |
United States Patent
Application |
20140208726 |
Kind Code |
A1 |
Karim; MD Anwarul ; et
al. |
July 31, 2014 |
Air Shielded Water Cooled Exhaust Manifold With Exhaust Tube
Support
Abstract
An internal combustion engine includes a cylinder block defining
at least one cylinder, and a cylinder head coupled to the cylinder
block. An exhaust manifold is coupled to the cylinder head and
configured to receive exhaust gas from the cylinder head. The
exhaust manifold includes a water jacket tube defining a plurality
of liquid coolant passages and an exhaust tube received within the
water jacket tube. The exhaust manifold also includes an air gap
between the exhaust tube and the water jacket tube. A support mat
is positioned in the air gap and compressed between an outer
surface of the exhaust tube and an inner surface of the water
jacket tube.
Inventors: |
Karim; MD Anwarul; (Peoria,
IL) ; Sarsfield; Robert A.; (Dunlap, IL) ;
Barb; Daniel Richard; (Germantown Hills, IL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
CATERPILLAR, INC. |
Bloomington |
IN |
US |
|
|
Assignee: |
CATERPILLAR, INC.
Bloomington
IN
|
Family ID: |
51163621 |
Appl. No.: |
13/753660 |
Filed: |
January 30, 2013 |
Current U.S.
Class: |
60/321 ;
29/890.08 |
Current CPC
Class: |
F01N 13/102 20130101;
F01N 3/046 20130101; Y10T 29/49398 20150115; Y02T 10/20 20130101;
Y02T 10/12 20130101 |
Class at
Publication: |
60/321 ;
29/890.08 |
International
Class: |
F01N 3/04 20060101
F01N003/04 |
Claims
1. An internal combustion engine, comprising: a cylinder block
defining at least one cylinder; a cylinder head coupled to the
cylinder block; an exhaust manifold coupled to the cylinder head
and configured to receive exhaust gas from the cylinder head,
wherein the exhaust manifold includes a water jacket tube defining
a plurality of liquid coolant passages and an exhaust tube received
within the water jacket tube, wherein the exhaust manifold includes
an air gap between the exhaust tube and the water jacket tube; and
a support mat positioned in the air gap, wherein the support mat is
compressed between an outer surface of the exhaust tube and an
inner surface of the water jacket tube.
2. The internal combustion engine of claim 1, wherein the support
mat includes a high temperature insulation material.
3. The internal combustion engine of claim 2, wherein the support
mat defines a continuous annular band.
4. The internal combustion engine of claim 2, wherein the high
temperature insulation material is intumescent.
5. The internal combustion engine of claim 2, wherein the support
mat has a compressed radial thickness of between about 3
millimeters and about 20 millimeters.
6. The internal combustion engine of claim 5, wherein the support
mat has an axial length of between about 75 millimeters and about
125 millimeters.
7. The internal combustion engine of claim 1, wherein the exhaust
manifold is a modular exhaust manifold including a plurality of
exhaust manifold segments coupled together along a common axis,
wherein each of the exhaust manifold segments includes a segment of
the water jacket tube and a segment of the exhaust tube received
within the water jacket tube segment.
8. The internal combustion engine of claim 7, wherein each exhaust
manifold segment includes at least one support mat compressed
between the exhaust tube segment and the water jacket tube
segment.
9. The internal combustion engine of claim 8, wherein the at least
one support mat is positioned at a first end of each exhaust
manifold segment, and at a second end of each exhaust manifold
segment the exhaust tube segment has a flared end for receiving the
exhaust tube segment of an adjacent exhaust manifold segment.
10. The internal combustion engine of claim 7, wherein the exhaust
tube is configured to direct exhaust gas in a first direction
relative to the common axis and the liquid coolant passages are
configured to direct liquid coolant in a second direction relative
to the common axis that is opposite the first direction.
11. A modular exhaust manifold for an internal combustion engine,
comprising: a first exhaust manifold segment including a first
segment of a water jacket tube defining a first plurality of liquid
coolant passages and a first segment of an exhaust tube received
within the first water jacket tube segment; wherein the first
exhaust manifold segment includes a first air gap between the first
exhaust tube segment and the first water jacket tube segment; and a
first support mat positioned in the first air gap, wherein the
first support mat is compressed between an outer surface of the
first exhaust tube segment and an inner surface of the first water
jacket tube segment.
12. The modular exhaust manifold of claim 11, wherein the first
support mat includes a high temperature insulation material.
13. The modular exhaust manifold of claim 12, wherein the first
support mat defines a continuous annular band.
14. The modular exhaust manifold of claim 12, wherein the high
temperature insulation material is intumescent.
15. The modular exhaust manifold of claim 12, wherein the support
mat has a compressed radial thickness of between about 3
millimeters and about 20 millimeters.
16. The modular exhaust manifold of claim 15, wherein the support
mat has an axial length of between about 75 millimeters and about
125 millimeters.
17. The modular exhaust manifold of claim 11, further including: a
second exhaust manifold segment including a second segment of the
water jacket tube defining a second plurality of liquid coolant
passages and a second segment of the exhaust tube received within
the second water jacket tube segment; wherein the second exhaust
manifold segment includes a second air gap between the second
exhaust tube segment and the second water jacket tube segment; and
a second support mat positioned in the second air gap, wherein the
second support mat is compressed between an outer surface of the
second exhaust tube segment and an inner surface of the second
water jacket tube segment.
18. The modular exhaust manifold of claim 17, wherein the first
support mat is positioned at a first end of the first exhaust
manifold segment and the second support mat is positioned at a
first end of the second exhaust manifold segment, wherein at a
second end of the first exhaust manifold segment the first exhaust
tube segment has a flared end for receiving the second exhaust tube
segment.
19. A method of assembling a modular exhaust manifold for an
internal combustion engine, comprising steps of: assembling a first
exhaust manifold segment by: positioning a first support mat around
a first segment of an exhaust tube; receiving the first exhaust
tube segment within a first segment of a water jacket tube defining
a first plurality of liquid coolant passages; wherein the receiving
step includes compressing the first support mat between an outer
surface of the first exhaust tube segment and an inner surface of
the first water jacket tube segment; and maintaining an air gap
between the first exhaust tube segment and the first water jacket
tube segment with the first support mat.
20. The method of claim 19, further including: attaching a second
exhaust manifold segment to the first exhaust manifold segment;
wherein the attaching step includes receiving the first exhaust
tube segment of the first exhaust manifold segment within a flared
end of the second exhaust tube segment.
Description
TECHNICAL FIELD
[0001] The present disclosure relates generally to an air shielded
water cooled exhaust manifold including an exhaust tube received
within a water jacket tube, and more particularly to a support mat
positioned in an air gap between the exhaust tube and the water
jacket tube.
BACKGROUND
[0002] An exhaust manifold of an internal combustion engine is a
collection of conduits through which exhaust gases produced during
combustion are carried away from the engine. The exhaust manifold
typically receives exhaust gases from each of the engine cylinders
through exhaust valve ports in the cylinder head or cylinder block
of the engine. The exhaust manifold then routes the exhaust gases
through one or more aftertreatment components and/or one or more
turbines of a turbocharger before expelling the exhaust gases into
the atmosphere. During operation of the engine, the exhaust
manifold becomes very hot due to the extremely high temperatures of
the exhaust gases passing through the manifold. To reduce skin
temperature and improve heat rejection, some exhaust manifolds
include a water jacket near an exterior surface of the
manifold.
[0003] An exemplary exhaust gas line for an internal combustion
engine having a cooling liquid space is taught in U.S. Pat. No.
4,693,079 to Wuensche et al. (hereinafter Wuensche). In particular,
the Wuensche reference teaches an exhaust gas line assembled of
several housings, with each housing containing a cooling liquid
space. The cooling liquid spaces of adjacent housings are connected
with each other using a connecting nipple. It appears the
connecting nipples, along with interconnections between exhaust
tube segments, form the connections between the multiple housings.
Although there exists a variety of different manifold designs in
the art, it should be appreciated that there remains a continuing
need for manifold designs offering improvements, including, for
example, increased surface cooling, ease of manufacture or use, and
improved sealing.
[0004] The present disclosure is directed to one or more of the
problems or issues set forth above.
SUMMARY OF THE DISCLOSURE
[0005] In one aspect, an internal combustion engine includes a
cylinder block defining at least one cylinder, and a cylinder head
coupled to the cylinder block. An exhaust manifold is coupled to
the cylinder head and configured to receive exhaust gas from the
cylinder head. The exhaust manifold includes a water jacket tube
defining a plurality of liquid coolant passages and an exhaust tube
received within the water jacket tube. The exhaust manifold also
includes an air gap between the exhaust tube and the water jacket
tube. A support mat is positioned in the air gap and compressed
between an outer surface of the exhaust tube and an inner surface
of the water jacket tube.
[0006] In another aspect, a modular exhaust manifold for an
internal combustion engine includes a first exhaust manifold
segment including a first segment of a water jacket tube defining a
first plurality of liquid coolant passages and a first segment of
an exhaust tube received within the first water jacket tube
segment. The first exhaust manifold segment includes a first air
gap between the first exhaust tube segment and the first water
jacket tube segment. A support mat is positioned in the first air
gap and compressed between an outer surface of the first exhaust
tube segment and an inner surface of the first water jacket tube
segment.
[0007] In another aspect, a method of assembling a modular exhaust
manifold for an internal combustion engine includes a step of
assembling a first exhaust manifold segment by positioning a first
support mat around a first segment of an exhaust tube and receiving
the first exhaust tube segment within a first segment of a water
jacket tube defining a first plurality of liquid coolant passages.
The receiving step includes compressing the first support mat
between an outer surface of the first exhaust tube segment and an
inner surface of the first water jacket tube segment. The
assembling step also includes maintaining an air gap between the
first exhaust tube segment and the first water jacket tube segment
with the first support mat.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is a perspective view of an exemplary embodiment of
an internal combustion engine including a modular exhaust manifold,
according to the present disclosure;
[0009] FIG. 2 is a perspective view of a portion of an exhaust
manifold segment of the exemplary modular exhaust manifold of FIG.
1;
[0010] FIG. 3 is a perspective view of an exhaust manifold segment
defining an end of the modular exhaust manifold of FIG. 1;
[0011] FIG. 4 is a perspective view of an exemplary embodiment of a
bypass tube of the exhaust manifold segment of FIG. 2; and
[0012] FIG. 5 is a cross-sectional view of a joint between adjacent
exhaust manifold segments.
DETAILED DESCRIPTION
[0013] Referring to FIG. 1, there is shown a schematic view of an
internal combustion engine 10, which, for purposes of illustration,
and not limitation, may be that of a four-stroke, compression
ignition engine. The engine 10 generally includes a cylinder block
12, which extends along a longitudinal axis X between opposing ends
12a and 12b and defines a plurality of combustion chambers or
cylinders 14. According to the present disclosure, the engine 10
may be any type of engine (e.g., internal combustion, gas, diesel,
gaseous fuel, natural gas, propane, etc.), may be of any size, with
any number of cylinders, any type of combustion chamber (e.g.,
cylindrical, rotary spark ignition, compression ignition, 4-stroke
and 2-stroke, etc.), and in any configuration (e.g., "V," in-line,
radial, etc.). According to the exemplary configuration, the
cylinder block 12 defines two rows of eight longitudinally spaced
cylinders 14, resulting in a V-16 configuration. However, those
skilled in the art will appreciate that any configuration and
number of cylinders 14 may be applicable.
[0014] The exemplary engine 10 also includes a cylinder head 16 for
providing intake and exhaust flow communication with the cylinders
14 of each row. According to the exemplary embodiment, each
cylinder head 16 may include a number of cylinder head modules 18
corresponding to the number of cylinders 14 defined by the cylinder
block 12. However, it is contemplated that each cylinder head
module 18 may serve to provide flow communication with more than
one cylinder 14, such as, for example, two, three, or four
cylinders 14. The cylinder head modules 18 may be configured to be
decoupled individually from the cylinder block 12, thereby
permitting removal of a single cylinder head module 18, without
necessarily removing any other cylinder head modules 18. This
exemplary configuration may serve to simplify maintenance of the
engine 10, as should be appreciated by those skilled in the
art.
[0015] According to the present disclosure, the exemplary engine 10
also includes an exhaust manifold or, more specifically, a modular
exhaust manifold 20 coupled to each cylinder head 16 to provide
flow communication between exhaust ports of the cylinder head 16
and the surroundings. The exemplary engine 10 includes four
turbochargers 22 located generally at one longitudinal end of
engine 10 (e.g., the opposite end 12b of the engine 10). According
to the exemplary embodiment, two turbochargers 22 may be associated
with each row of cylinders 14; however, other numbers of
turbochargers 22 are contemplated, along with embodiments having no
turbochargers. In the exemplary embodiment shown, the modular
exhaust manifold 20 extends along the longitudinal axis X and
provides flow communication between the cylinder heads 16 and the
turbochargers 22.
[0016] As shown in FIG. 1, each exemplary modular exhaust manifold
20 includes a plurality of exhaust manifold segments 24 coupled to
one another in end-to-end fashion along the common longitudinal
axis X of the engine 10. Although a segmented exhaust manifold 20
is shown, it should be appreciated that a unitary, or
non-segmented, manifold may alternatively be utilized. According to
some embodiments, the exhaust manifold segments 24 may have a
substantially circular cross-section, although other cross-sections
are contemplated. According to the exemplary embodiment, the
exhaust manifold segments 24 may be configured to direct exhaust
gas in a first direction d.sub.1 relative to the longitudinal axis
X, while liquid coolant, such as water and/or a known coolant
(e.g., a glycol-based coolant), is directed in a second direction
d.sub.2 relative to the longitudinal axis X that is opposite the
first direction d.sub.1.
[0017] In the example shown, an exhaust manifold segment 24a
located at an end of the modular exhaust manifold 20 opposite
turbochargers 22 (i.e., end 12a) includes an end cap 26 (e.g., a
removable end cap) preventing flow communication between modular
exhaust manifold 20 and the surroundings via exhaust manifold
segment 24a. At an end of the modular exhaust manifold 20 opposite
the exhaust manifold segment 24a (i.e., end 12b), an exhaust
manifold segment 24b is coupled to a rise manifold section 28
extending between exhaust manifold segment 24b and turbochargers
22.
[0018] As shown at exhaust manifold segment 24c (shown with
portions removed), each exhaust manifold segment 24 includes an
exhaust tube segment 30 configured to receive exhaust gas from an
exhaust port 32 of the respective cylinder head module 18. Each
exhaust manifold segment 24 also includes a water jacket tube
segment 34 (shown, for example, at segment 24b) configured to
receive a liquid coolant. As will become more apparent below, the
exhaust tube segment 30 of each exhaust manifold segment 24 is
telescopically received within a respective water jacket tube
segment 34. Although not discussed in detail herein, each exhaust
manifold segment 24 may include an adaptor tube coupled at one end
to the water jacket tube segment 24 and at an opposite end to the
respective cylinder head module 18. The adaptor tubes may be
configured to provide flow communication between the cylinder head
16 and the exhaust tube segment 30 of each exhaust manifold segment
24. However, alternative arrangements for fluidly connecting the
exhaust tube segments 30 with the cylinder head 16 are also
contemplated.
[0019] Turning now to FIG. 2, an exemplary exhaust manifold segment
24, components of which may be made from aluminum or other suitable
material, will be discussed in greater detail. In particular, and
according to the present disclosure, at least one end 40 of each
exhaust manifold segment 24 may include a radial flange 42 defining
an engagement face 44, or surface, configured for coupling adjacent
exhaust manifold segments 24 together using known attachment means.
For example, removable fasteners, such as bolts, may be positioned
through corresponding openings, such as threaded bores, of each
engagement face 44 to secure a coupled position of adjacent exhaust
manifold segments 24. However, alternative coupling means are also
contemplated. As shown, a first sealing member 46 may be positioned
along the engagement face 44 and may include a gasket 48, such as a
multiple layers steel (MLS) gasket, positioned over the engagement
face 44 and around the exhaust tube segment 30.
[0020] At least one bypass opening 50 may be provided through the
engagement face 44 for transferring liquid coolant from one exhaust
manifold segment 24 to another. According to the exemplary
embodiment, the liquid coolant passages defined by the water jacket
tube segment 34 may converge toward one of exactly two bypass
openings 50; however, the number of bypass openings 50 may vary.
For example, as shown in FIG. 3, three bypass openings 50 may be
provided. The exhaust manifold segment 24 of FIG. 3, which includes
features similar to those of FIG. 2, may represent exhaust manifold
segment 24a positioned at end 12a of the engine 10. The end cap 26,
shown in FIG. 1, may be positioned over the engagement face 44 of
the exhaust manifold segment 24 of FIG. 3. As should be
appreciated, the first sealing member 46 may have differing sizes
and/or shapes, depending on the particular application.
[0021] As shown in both FIG. 2 and FIG. 3, the bypass openings 50
may be radially spaced from the exhaust tube segment 30 and may be
free of contact with the gasket 48. A bypass tube 52, shown also in
FIG. 4, may be positioned through each bypass opening 50 of each of
the adjacent exhaust manifold segments 24 to fluidly connect the
liquid coolant passages of adjacent exhaust manifold segments 24. A
second sealing member 54 may be positioned about the bypass tube 52
and may include a radial seal positioned within an external groove
56 within the external surface of the bypass tube 52. As shown in
FIG. 4, and as will be discussed in greater detail below, each
bypass tube 52 may include a first o-ring seal 58 positioned about
the bypass tube 52 at a first longitudinal position and a second
o-ring seal 60 positioned about the bypass tube 52 at a second
longitudinal position which is spaced from the first longitudinal
position.
[0022] Turning now to FIG. 5, coupled exhaust manifold segments,
which are similar to exhaust manifold segments 24 described above,
will be discussed. In particular, a first exhaust manifold segment
70 includes a first segment 72 of a water jacket tube 74 defining a
first plurality of liquid coolant passages 76 and a first segment
78 of an exhaust tube 80 received within the first water jacket
tube segment 72. Similarly, a second exhaust manifold segment 82
includes a second segment 84 of the water jacket tube 74 defining a
second plurality of liquid coolant passages 86 and a second segment
88 of the exhaust tube 80 received within the second water jacket
tube segment 84. The first and second exhaust tube segments 78 and
88 each receive exhaust gases from a respective cylinder head
module 18 and, when coupled together to define a modular exhaust
manifold such as exhaust manifold 22 of FIG. 1, define the engine
exhaust tube 80. Further, each of the sets of liquid coolant
passages 76 and 86 are joined together when the water jacket tube
segments 72 and 84 are coupled to ultimately define the water
jacket tube 74.
[0023] An air gap 91 is provided between the exhaust tube 80 and
the water jacket tube 74. In particular, the first exhaust manifold
segment 70 includes a first air gap 91a between the first exhaust
tube segment 78 and the first water jacket tube segment 72, and the
second exhaust manifold segment 82 includes a second air gap 91b
between the second exhaust tube segment 88 and the second water
jacket tube segment 84. The air gap 91 may provide an insulation
shield between the exhaust tube 80 and the water jacket tube 74,
and may contain a fluid, such as, for example, air and/or another
gas. In particular, the air gap 91 may reduce the amount of energy
transmitted to the liquid coolant from the exhaust tube 80.
[0024] A support mat 90 is positioned in the air gap 91 and, more
particularly, is compressed between an outer surface 93 of the
exhaust tube 80 and an inner surface 95 of the water jacket tube
74. The support mat 90 may assist in maintaining the air gap 91
between the exhaust tube 80 and the water jacket tube 74 and,
according to some embodiments, may be made from a high temperature
insulation material, such as, for example, refractory ceramic
fibers, vermiculite, mullite, and/or polycrystalline. These
materials may be intumescent or non-intumescent. For example, the
thermal expansion of an intumescent material, such as vermiculite,
may be preferred to increase the pressure acting on the support mat
90 and help secure the positioning of the support mat 90 within the
air gap 91. The high temperature insulation material of the support
mat 90, which may be held together using a known binder, may
transfer a relatively low amount of thermal energy from the exhaust
tube 80 to the water jacket tube 74, particularly when compared to
support structures made from alternative materials.
[0025] According to an exemplary embodiment, the support mat 90 may
define a continuous annular band 97 having a substantially uniform
compressed radial thickness tx. For example, according to one
particular embodiment, the compressed radial thickness tx may be
between about 3 millimeters and about 20 millimeters. An axial
length/of the support mat 90 may be between about 75 millimeters
and about 125 millimeters. It should be appreciated that
configurations of the support mat 90, including dimensions and
materials, may vary depending on the particular application.
Further, although a continuous structure is described, it should be
appreciated that the support mat 90 may alternatively be defined by
a plurality of discontinuous members.
[0026] Although any number of support mats 90 may be used, some
embodiments may include a single support mat 90 positioned at a
first end 92 of each of the exhaust manifold segments 70 and 82.
That is, the first support mat 90a may be positioned at a first end
92a of the first exhaust manifold segment 78, and the second
support mat 90b may be positioned at a first end 92b of the second
exhaust manifold segment 82. At a second end 102 of each of the
exhaust manifold segments 70 and 82, the exhaust tube segment 78,
88 may have a flared end 99 for receiving the exhaust tube segment
78, 88 of an adjacent exhaust manifold segment, such as exhaust
manifold segments 78 and 88, when coupled. As shown, the flared end
99 of the second exhaust tube segment 88 may receive the first
exhaust tube segment 78. According to some embodiments, at the
second end 102 of each of the exhaust manifold segments 70 and 82,
the water jacket tube segment 72, 84 may include a longitudinally
extending portion 101 received within a respective one of the water
jacket tube segments 72, 84. The longitudinally extending portion
101 may contact the support mat 90 and restrict axial movement of
the support mat 90 beyond the longitudinally extending portion
101.
[0027] The first end 92a of the first water jacket tube segment 72
includes a first radial flange 94 defining a first engagement face
96 configured for coupling the first exhaust manifold segment 70
with the second exhaust manifold segment 82. The first water jacket
tube segment 72 also defines a first radial bypass channel 98,
extending radially as the channel 98 approaches the first end 92a,
fluidly connecting at least one of the first plurality of liquid
coolant passages 76 with a first bypass opening 100 through the
first engagement face 96. Similarly, the second end 102b of the
second water jacket tube segment 84 includes a second radial flange
104 defining a second engagement face 106 configured for coupling
the second exhaust manifold segment 82 with the first exhaust
manifold segment 70. The second water jacket tube segment 84 also
defines a second radial bypass channel 108 fluidly connecting at
least one of the second plurality of liquid coolant passages 86
with a second bypass opening 110 through the second engagement face
106.
[0028] A joint 112 between the first and second exhaust manifold
segments 70 and 82 includes a first sealing member 114 configured
to seal the exhaust tube 80 at the joint 112, and a second sealing
member 116 configured to seal the liquid coolant passages 76 and 86
of the water jacket tube 74 at the joint 112. According to the
present disclosure, the first and second sealing members 114 and
116 are supported on and movable with different components. For
example, the first sealing member 114 may include a gasket 118
positioned between the first and second engagement faces 96 and 106
and attached in a known manner. The second sealing member 116 may
include first and second o-ring seals 120 and 122 positioned about
a bypass tube 124, as described above with reference to FIG. 4. The
bypass tube 124 may be positioned through the first bypass opening
100 and the second bypass opening 110 to fluidly connect a portion
of the first plurality of liquid coolant passages 76 and a portion
of the second plurality of liquid coolant passages 86. The first
o-ring seal 120 may be positioned about the bypass tube 124 and
within the first radial bypass channel 98, and the second o-ring
seal 122 may be positioned about the bypass tube 124 and within the
second radial bypass channel 108.
[0029] Gaps 126 and 128 may be provided at either end of the bypass
tube 124 between the bypass tube 124 and an end stop or shoulder
within the respective radial bypass channel 98 and 108. Such gaps
126 and 128 may permit movement of the bypass tube 124 as the water
jacket tube segments 72 and 84 shift or bow as a result of thermal
expansion. Positioning the o-ring seals 120 and 124 within the
radial bypass channels 98 and 108 allows for the sealing of the
liquid coolant passages 76 and 86 of the water jacket tube 74 at
the joint 112 even during any axial shifting of the bypass tube 124
that may occur. It should be appreciated that the exhaust tube
segments 78 and 88 may also be joined at a slip joint to permit
limited movement.
[0030] Industrial Applicability
[0031] The present disclosure may be applicable to internal
combustion engines having exhaust manifolds. Further, the present
disclosure may be applicable to exhaust manifolds having water
jackets for reducing the skin temperature of the exhaust manifold.
Further, the present disclosure may be applicable to air shielded
water cooled exhaust manifolds. Yet further, the present disclosure
may be applicable to modular manifold designs offering improved
manufacturability and serviceability.
[0032] Referring generally to FIGS. 1-5, an exemplary internal
combustion engine 10 generally includes a cylinder block 12
defining a plurality of cylinders 14. A cylinder head 16 is coupled
to the cylinder block 12 and provides intake and exhaust flow
communication with the cylinders 14. The exemplary engine 10 also
includes a modular exhaust manifold 20, as disclosed herein,
coupled to each cylinder head 16 to provide flow communication
between exhaust ports of the cylinder head 16 and the surroundings.
As shown in FIG. 1, each exemplary modular exhaust manifold 20
includes a plurality of exhaust manifold segments 24 coupled to one
another in end-to-end fashion along a common longitudinal axis X of
the engine 10.
[0033] The modularity of the exhaust manifold 20, as described
herein, provides advantages at least from a manufacturability
and/or serviceability standpoint. In particular, by utilizing a
plurality of similar exhaust manifold segments 24, similar parts
may be manufactured for engines of different sizes and/or
configurations. For example, manufacturing the engine 10 shown in
FIG. 1 requires the use of four exhaust manifold segments 24 for
each cylinder head 16, with each exhaust manifold segment 24
corresponding to two cylinders 14. The resulting V-16 engine 10
thus requires the use of eight exhaust manifold segments 24.
Manufacturing a V-12 engine, however, may only require the use of
six of the exhaust manifold segments 24.
[0034] Serviceability may also be improved by the modularity of the
manifold design. In particular, maintenance times and resulting
costs may be reduced by minimizing the number of parts to be
removed during the servicing or repair. In particular, accessing a
cylinder 14 or cylinder head module 18 may require removal of only
the corresponding exhaust manifold segment 24 without the need to
remove the entire exhaust manifold 20. Thus, according to the
modular exhaust manifold 20 disclosed herein, it may be possible to
perform maintenance associated with one cylinder 14 more easily
relative to an engine that includes a unitary manifold.
[0035] As described above, and with specific reference to FIG. 5,
adjacent exhaust manifold segments 70 and 82 each include a water
jacket tube segment 72 and 84 and an exhaust tube segment 78 and 88
received within the water jacket tube segment 72 and 84. A joint
112 between adjacent exhaust manifold segments 70 and 82 includes a
first sealing member 114 configured to seal the exhaust tube 80 at
the joint 112 and a second sealing member 116 configured to seal
the liquid coolant passages 76 and 86 at the joint 112. For
example, the first sealing member 114 may include a gasket 118
positioned bb of the adjacent exhaust manifold segments 70 and 82.
In particular, adjoining ends 92a and 102b of the adjacent exhaust
manifold segments 70 and 82 each include a radial flange 94 and 104
defining the engagement faces 96 and 106, which are configured for
coupling the adjacent exhaust manifold segments 70 and 82 together.
When the exhaust manifold segments 70 and 82 are coupled, the first
sealing member 114, supported on one or both of the engagement
faces 96 and 106, effectively seals the exhaust tube 80 at the
joint 112.
[0036] Coupling the adjacent exhaust manifold segments 70 and 82
also secures a relative position of one or more bypass tubes 124
within radial bypass channels 98 and 108 of the respective exhaust
manifold segments 70 and 82. In particular, each bypass tube 124 is
positioned through bypass openings 100 and 110 through the
respective engagement faces 96 and 106. A first o-ring seal 120 is
positioned about the bypass tube 124 and within the radial bypass
channel 98 of the first exhaust manifold segment 70, and a second
o-ring seal 122 is positioned about the bypass tube 124 and within
the radial bypass channel 108 of the second exhaust manifold
segment 82. The second sealing member 116, which may include the
first and second o-ring seals 120 and 122, is supported on the
bypass tube 124 and effectively seals the liquid coolant passages
76 and 86 of the water jacket tube 74 at the joint 112.
[0037] Support mats 90a and 90b may be positioned in a respective
one of air gaps 91a and 91b between the exhaust tube 80 and the
water jacket tube 74. During assembly, each of the first and second
exhaust manifold segments 70 and 82 may be assembled prior to
coupling the first and second exhaust manifolds segments 70 and 82
as shown in FIG. 5. In particular, a first support mat 90a may be
positioned around the first exhaust tube segment 78 before the
first exhaust tube segment 78 is received within the first water
jacket tube segment 72. During this assembly, the first support mat
90a is compressed between an outer surface 93 of the first exhaust
tube segment 78 and an inner surface 95 of the first water jacket
tube segment 72. After the second exhaust manifold segment 82 is
similarly assembled, the first and second exhaust manifold segments
70 and 82 may be coupled together as described above. When the
adjacent exhaust manifold segments 70 and 82 are coupled together,
the first exhaust tube segment 78 of the first exhaust manifold
segment 70 is received within a flared end 99 of the second exhaust
tube segment 88. Thus, at a first end 92b of the second exhaust
manifold segment 82, the second exhaust tube segment 88 is
supported within the second water jacket tube segment 84 using the
second support mat 90b, while, at a second end 102b of the second
exhaust manifold segment 82, the flared end 99 is supported by the
first exhaust tube segment 78.
[0038] The air gap 91 may provide an insulation shield between the
exhaust tube 80 and the water jacket tube 74. In particular, the
air gap 91 may reduce the amount of thermal energy transmitted to
the liquid coolant from the exhaust tube 80. The support mats 90
may assist in supporting the exhaust tube 80 and maintaining the
air gap 91. Preferably, the support mats 90 are made from a high
temperature insulation material and, thus, may transfer a
relatively low amount of thermal energy from the exhaust tube 80 to
the water jacket tube 74, particularly when compared to support
structures made from alternative materials. Further, the support
mats 90 may be sized and configured to distribute forces, including
vibrations, transmitted between the components over a larger area
than alternative structures. Ultimately, the support mats 90 may
reduce premature wear of the water jacket tube 74 that might
otherwise be caused by heat and forces transferred from the exhaust
tube 80.
[0039] It should be understood that the above description is
intended for illustrative purposes only, and is not intended to
limit the scope of the present disclosure in any way. Thus, those
skilled in the art will appreciate that other aspects of the
disclosure can be obtained from a study of the drawings, the
disclosure and the appended claims.
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