U.S. patent application number 14/713494 was filed with the patent office on 2015-11-19 for device for heat exchange.
This patent application is currently assigned to BorgWarner Emissions Systems Spain, S.L.U.. The applicant listed for this patent is BorgWarner Inc.. Invention is credited to Rodolfo Prieto Dominguez, Xoan Xose Hermida Dominguez, Simon Pineiro Losada.
Application Number | 20150330712 14/713494 |
Document ID | / |
Family ID | 51059397 |
Filed Date | 2015-11-19 |
United States Patent
Application |
20150330712 |
Kind Code |
A1 |
Losada; Simon Pineiro ; et
al. |
November 19, 2015 |
DEVICE FOR HEAT EXCHANGE
Abstract
The present invention is a device for heat exchange particularly
suitable for cooling recirculated gas in EGR (Exhaust Gas
Recirculation) systems, with a constructive configuration
incorporating the heat exchanger together with a bypass conduit and
a bypass valve, where most of the parts forming said device allow
manufacturing same in stamped sheet metal, thereby reducing
manufacturing costs.
Inventors: |
Losada; Simon Pineiro;
(Vigo, ES) ; Dominguez; Rodolfo Prieto; (Vigo,
ES) ; Dominguez; Xoan Xose Hermida; (Gondomar,
ES) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
BorgWarner Inc. |
Auburn Hills |
MI |
US |
|
|
Assignee: |
BorgWarner Emissions Systems Spain,
S.L.U.
Vigo
ES
|
Family ID: |
51059397 |
Appl. No.: |
14/713494 |
Filed: |
May 15, 2015 |
Current U.S.
Class: |
165/103 ;
165/154 |
Current CPC
Class: |
F02M 26/26 20160201;
F02M 26/32 20160201; F28D 21/0003 20130101; F28F 2250/06 20130101;
F28D 1/053 20130101; F28F 27/02 20130101; F28D 7/16 20130101; F28D
1/0408 20130101; F28F 13/06 20130101; F28D 1/0443 20130101 |
International
Class: |
F28D 1/04 20060101
F28D001/04; F28F 13/06 20060101 F28F013/06; F28D 1/053 20060101
F28D001/053 |
Foreign Application Data
Date |
Code |
Application Number |
May 16, 2014 |
EP |
14382172.6 |
Claims
1. A heat exchange device for heat exchange between a first fluid
circulating through a first conduit; and a second fluid circulating
through a second conduit, where said device is intended for being
intercalated between both conduits and comprises: a sheet metal
shell having a tubular configuration, a first sheet metal baffle
and a second sheet metal baffle assembled in the sheet metal shell
and spaced from one another, a bundle of conduits extending along a
longitudinal direction at least from the first baffle to the second
baffle, a bypass conduit extending at least from the first baffle
to the second baffle and it is parallel to the bundle of conduits,
a fluid communication inlet and a fluid communication outlet for
the second fluid, both arranged in the sheet metal shell and giving
access to the space located between the first baffle and the second
baffle for cooling the bundle of conduits, a first fluid
communication inlet/outlet arranged at one of the ends of the
bundle of conduits and of the bypass conduit, and a second fluid
communication inlet/outlet arranged at the opposite end of the
bundle of conduits and of the bypass conduit, both the fluid
communication inlet/outlet giving access to the first fluid through
the bundle of conduits, through the bypass conduit or through both,
where the tubular sheet metal shell extends longitudinally beyond
the second baffle giving rise to a chamber such that said chamber
comprises a valve that can be actuated from outside the chamber and
is adapted to at least close the bypass conduit, and where said
valve comprises a shaft attached to the sheet metal shell and
capable of rotating with respect to said shell, prolonging into the
chamber where said shaft comprises a sheet metal flap adapted to
sit on the perimetric edge of the end of the bypass conduit for
closing same.
2. The device according to claim 1, where the shaft is attached to
the sheet metal shell by means of the interposition of a support
with the shaft going through same, such that said support is
integral with the sheet metal shell, and where the support allows
rotation of the shaft.
3. The device according to claim 2, where the sheet metal shell
comprises a perforation for the passage of the rotating shaft, and
where the support of the shaft and said shaft are adapted to allow
mutual coupling by inserting the shaft from inside the chamber
through the perforation.
4. The device according to claim 2, where the sheet metal shell
comprises an open groove for the passage of the rotating shaft
extending to the end where the chamber is located, and where said
groove is configured such that the assembly formed by the support
of the shaft and said shaft as well as the base allows inserting
the shaft through the open groove to the final position of the base
on the sheet metal shell.
5. The device according to claim 2, where the support is integral
with the sheet metal shell by means of the interposition of a base
such that the base is attached to the sheet metal shell and the
support of the shaft is arranged on the base.
6. The device according to claim 5, where the sheet metal shell
comprises an open groove for the passage of the rotating shaft
extending to the end where the chamber is located, and where said
groove is configured such that the assembly formed by the support
of the shaft and said shaft as well as the base allows inserting
the shaft through the open groove to the final position of the base
on the sheet metal shell.
7. The device according to claim 5, where an extension of the base
is the support of an actuator for operating the shaft.
8. The device according to claim 1, where the sheet metal shell
having a tubular configuration shows an expansion step intended for
housing the second sheet metal baffle.
9. The device according to claim 1, where the bypass conduit
comprises a first outer tube and a second inner tube forming
between them a thermal insulation chamber.
10. The device according to claim 1, where the chamber is closed by
means of a sheet metal cover.
11. The device according to claim 1, where the chamber comprises a
stamped sheet metal part dividing the chamber into an inner
sub-chamber in communication with the inside of the tubes of the
bundle of conduits and an outer sub-chamber, and where said stamped
sheet metal part comprises a first opening and a second opening
such that: the stamped sheet metal part establishes a perimetric
closure with the shell, the first opening establishes fluid
communication between the inner sub-chamber and the outer
sub-chamber, the second opening perimetrically surrounds the bypass
conduit; and the second fluid communication inlet/outlet is in
direct communication with the outer sub-chamber.
12. The device according to claim 11, where the first opening and
the second opening of the stamped sheet metal part comprise a valve
seat.
13. The device according to claim 12, where the shaft of the valve
comprises a second flap such that: the first flap is adapted to
close on the seat of the second opening, the second flap is adapted
to close on the seat of the first opening of the stamped sheet
metal part; and where the first flap and the second flap are
configured for adopting at least two end positions, a first end
position where the first flap establishes the closure of the bypass
conduit in a first angular position of the shaft; and a second end
position where the second flap establishes the closure of the
second opening in a second angular position of the same shaft.
14. The device according to claim 11, where the seat of the second
opening is either: in a tube end-shaped termination of said second
opening; or on the perimetric edge of the end of the bypass conduit
where this bypass conduit axially goes beyond the position of said
second opening.
15. The device according to claim 11, where the shaft of the valve
comprises a second flap such that: the first flap is adapted to
close on the seat of the second opening, the second flap is adapted
to close on the seat of the first opening of the stamped sheet
metal part; and where the first flap and the second flap are
configured for adopting at least two end positions, a first end
position where the first flap establishes the closure of the bypass
conduit in a first angular position of the shaft; and a second end
position where the second flap establishes the closure of the
second opening in a second angular position of the same shaft.
16. The device according to claim 1, where the flap or flaps have a
concave protuberance adapted to enter the cavity on which the seat
of said flap is located for making it stiff in the event of
temperature changes.
17. A heat exchange device for heat exchange between a first fluid
circulating through a first conduit; and a second fluid circulating
through a second conduit, where said device is intended for being
intercalated between both conduits and comprises: a sheet metal
shell having a tubular configuration, a first sheet metal baffle
and a second sheet metal baffle assembled in the sheet metal shell
and spaced from one another, a bundle of conduits extending along a
longitudinal direction at least from the first baffle to the second
baffle, a bypass conduit extending at least from the first baffle
to the second baffle and it is parallel to the bundle of conduits,
a fluid communication inlet and a fluid communication outlet for
the second fluid, both arranged in the sheet metal shell and giving
access to the space located between the first baffle and the second
baffle for cooling the bundle of conduits, a first fluid
communication inlet/outlet arranged at one of the ends of the
bundle of conduits and of the bypass conduit, and a second fluid
communication inlet/outlet arranged at the opposite end of the
bundle of conduits and of the bypass conduit, both the fluid
communication inlet/outlet giving access to the first fluid through
the bundle of conduits, through the bypass conduit or through both,
where the tubular sheet metal shell extends longitudinally beyond
the second baffle giving rise to a chamber such that said chamber
comprises a valve that can be actuated from outside the chamber and
is adapted to at least close the bypass conduit, and where said
valve comprises a shaft attached to the sheet metal shell and
capable of rotating with respect to said shell, prolonging into the
chamber where said shaft comprises a sheet metal flap adapted to
sit on the perimetric edge of the end of the bypass conduit for
closing same, and where the support is integral with the sheet
metal shell by means of the interposition of a base such that the
base is attached to the sheet metal shell and the support of the
shaft is arranged on the base and where the sheet metal shell
comprises an open groove for the passage of the rotating shaft
extending to the end where the chamber is located, and where said
groove is configured such that the assembly formed by the support
of the shaft and said shaft as well as the base allows inserting
the shaft through the open groove to the final position of the base
on the sheet metal shell, and where the shaft of the valve
comprises a second flap such that: the first flap is adapted to
close on the seat of the second opening, the second flap is adapted
to close on the seat of the first opening of the stamped sheet
metal part; and where the first flap and the second flap are
configured for adopting at least two end positions, a first end
position where the first flap establishes the closure of the bypass
conduit in a first angular position of the shaft; and a second end
position where the second flap establishes the closure of the
second opening in a second angular position of the same shaft.
18. The device according to claim 17 where the flap or flaps have a
concave protuberance adapted to enter the cavity on which the seat
of said flap is located for making it stiff in the event of
temperature changes.
19. A heat exchange device for heat exchange between a first fluid
circulating through a first conduit; and a second fluid circulating
through a second conduit, where said device is intended for being
intercalated between both conduits and comprises: a sheet metal
shell having a tubular configuration, a first sheet metal baffle
and a second sheet metal baffle assembled in the sheet metal shell
and spaced from one another, a bundle of conduits extending along a
longitudinal direction at least from the first baffle to the second
baffle, a bypass conduit extending at least from the first baffle
to the second baffle and it is parallel to the bundle of conduits,
a fluid communication inlet and a fluid communication outlet for
the second fluid, both arranged in the sheet metal shell and giving
access to the space located between the first baffle and the second
baffle for cooling the bundle of conduits, a first fluid
communication inlet/outlet arranged at one of the ends of the
bundle of conduits and of the bypass conduit, and a second fluid
communication inlet/outlet arranged at the opposite end of the
bundle of conduits and of the bypass conduit, both the fluid
communication inlet/outlet giving access to the first fluid through
the bundle of conduits, through the bypass conduit or through both,
where the tubular sheet metal shell extends longitudinally beyond
the second baffle giving rise to a chamber such that said chamber
comprises a valve that can be actuated from outside the chamber and
is adapted to at least close the bypass conduit, and where said
valve comprises a shaft attached to the sheet metal shell and
capable of rotating with respect to said shell, prolonging into the
chamber where said shaft comprises a sheet metal flap adapted to
sit on the perimetric edge of the end of the bypass conduit for
closing same, and where the support is integral with the sheet
metal shell by means of the interposition of a base such that the
base is attached to the sheet metal shell and the support of the
shaft is arranged on the base and where the sheet metal shell
comprises an open groove for the passage of the rotating shaft
extending to the end where the chamber is located, and where said
groove is configured such that the assembly formed by the support
of the shaft and said shaft as well as the base allows inserting
the shaft through the open groove to the final position of the base
on the sheet metal shell, where the shaft of the valve comprises a
second flap such that: the first flap is adapted to close on the
seat of the second opening, the second flap is adapted to close on
the seat of the first opening of the stamped sheet metal part;
where the first flap and the second flap are configured for
adopting at least two end positions, a first end position where the
first flap establishes the closure of the bypass conduit in a first
angular position of the shaft; and a second end position where the
second flap establishes the closure of the second opening in a
second angular position of the same shaft, and where the flap or
flaps have a concave protuberance adapted to enter the cavity on
which the seat of said flap is located for making it stiff in the
event of temperature changes, and where the chamber comprises a
stamped sheet metal part dividing the chamber into an inner
sub-chamber in communication with the inside of the tubes of the
bundle of conduits and an outer sub-chamber, and where said stamped
sheet metal part comprises a first opening and a second opening
such that: the stamped sheet metal part establishes a perimetric
closure with the shell, the first opening establishes fluid
communication between the inner sub-chamber and the outer
sub-chamber, the second opening perimetrically surrounds the bypass
conduit; and the second fluid communication inlet/outlet is in
direct communication with the outer sub-chamber.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of European Patent
Application Serial No. EP14382172.6 filed May 16, 2014.
TECHNICAL FIELD
[0002] The present invention is a device for heat exchange
particularly suitable for cooling recirculated gas in EGR (Exhaust
Gas Recirculation) systems, with a constructive configuration
incorporating the heat exchanger together with a bypass conduit and
a bypass valve, where most of the parts forming said device allow
manufacturing same in stamped sheet metal, thereby reducing
manufacturing costs.
BACKGROUND
[0003] Heat exchanger devices for EGR systems are devices intended
for cooling recirculated gas originating from combustion in an
internal combustion engine until it reaches a temperature suitable
for being reintroduced into the intake. The reintroduction of
recirculated gas reduces the amount of oxygen entering the
combustion chamber, such that nitrogen oxide emission is
reduced.
[0004] Cooling of exhaust gases is not suitable when the engine has
just been started and the temperature thereof is too low. It is of
interest for the engine and specific conduits to reach a specific
temperature in the shortest time possible, since the existence of
condensates causes very significant engine damage.
[0005] To prevent cooling of said exhaust gases in these
conditions, the heat exchanger of the EGR system has a bypass
conduit which is open depending on the position of a bypass valve.
The exhaust gas goes through the bypass conduit without giving off
its heat to the coolant circulating in the heat exchanger.
[0006] The configuration of this bypass valve usually has seats
made on injected or molten metal parts, where these metal parts are
machined to assure both the proper operation of the moving portions
of the valve and the correct closure of the flap on the seats.
[0007] It is expensive to manufacture these metal parts obtained
either by injection or by melting and subsequently assemble them
compared to other types of techniques such as stamping.
Nevertheless, stamping is also severely limited by the shapes that
each of the stamped parts can adopt.
[0008] An object of the present invention is to provide a
configuration of a heat exchanger with a bypass conduit and bypass
valve, where most of the parts of the device allow manufacturing
same in stamped sheet metal, reducing manufacturing costs.
DESCRIPTION OF THE INVENTION
[0009] The heat exchange device establishes exchange between a
first fluid and a second fluid. In the preferred example, the first
fluid is the gas to be cooled in an internal combustion engine with
an EGR system for reintroduction into the intake manifold; and the
second fluid is a coolant absorbing the heat given off by the gas.
The heat exchanging device is intercalated between the conduit of
the first fluid and the conduit of the second fluid existing in an
internal combustion engine.
[0010] It is of particular interest to reduce manufacturing costs
by establishing a configuration in which most of the parts of the
exchanger can be manufactured in die cut and/or pressed sheet
metal. The expression "can be manufactured" is used because
although the invention establishes a particular configuration that
allows the manufacture of part of the exchanger in sheet metal,
some of the parts that allow said manufacture in sheet metal can be
reproduced by means of injection or machining techniques, but this
by itself does not mean that the invention is not being
reproduced.
[0011] The heat exchanger comprises: [0012] a sheet metal shell
having a tubular configuration, [0013] a first sheet metal baffle
and a second sheet metal baffle assembled in the sheet metal shell
spaced from one another, [0014] a bundle of conduits extending
along a longitudinal direction X-X' at least from the first baffle
to the second baffle, [0015] a bypass conduit extending at least
from the first baffle to the second baffle and it is parallel to
the bundle of conduits.
[0016] The tubular configuration of the shell must be interpreted
in the most generic sense, where the section of the tubular body is
the generatrix and the longitudinal direction is the directrix. By
way of example, the tubular configuration of the sheet metal shell
can be formed by two U-shaped stamped sheet metal bodies that are
attached to one another giving rise to a tubular configuration
having a square or rectangular section.
[0017] The same applies to use of the expression bundle of
conduits. By way of example, the bundle of conduits can be formed
as a bundle of tubes, a bundle of hybrid tubes, each of them having
a flat or oval section, or each of them can also be obtained by
stamping two half-portions which are subsequently attached to one
another by welding. The bundle of conduits can also be interpreted
as a bundle formed by a stack of stamped metal sheets, being able
to have exchange fins, giving rise to the bundle of conduits.
[0018] The second fluid, the coolant in the preferred example,
flows through the inside of the shell in contact with the conduits
of the bundle of conduits. The first fluid, the gas to be cooled in
the preferred example, usually circulates through this bundle of
conduits such that the surface of the conduits of the bundle of
conduits is the exchange surface for transferring heat from the
first fluid to the second fluid.
[0019] The bypass conduit is arranged parallel to the bundle of
conduits. The bypass conduit is sized to allow the partial or
complete passage of the first fluid, depending on the position of
the flaps, preventing the complete or partial passage of said first
fluid through the conduits of the bundle of conduits, and therefore
preventing cooling thereof. When the bypass conduit has a large
diameter, even if it is immersed in the second fluid or coolant,
the ratio between the volume of circulating second fluid and the
exchange surface with respect to said second fluid is high, so heat
transfer is small, and although cooling occurs, the cost reduction
resulting from the incomplete insulation of the bypass conduit can
be justified considering the small heat transfer that has been
indicated. From another point of view, the bypass conduit has a
diameter that is much larger than the diameter of the conduits of
the bundle of conduits, such that the ratio between the exchange
surface and the flow is much lower in this case, giving rise to a
much lower degree of heat transfer. Diverting gas flow through the
bypass conduit involves drastically reducing the heat removed from
the gas flow.
[0020] According to other embodiments, the bypass conduit is
located inside another conduit or tube having a larger diameter,
leaving a chamber therein which drastically reduces the heat
transfer capacity between the first fluid and the second fluid.
[0021] a fluid communication inlet and a fluid communication outlet
for the second fluid, both arranged in the sheet metal shell and
giving access to the space located between the first baffle and the
second baffle for cooling the bundle of tubes.
[0022] This fluid communication allows circulating the second fluid
through the exchanger discharging, in the various embodiments, the
heat provided by the first fluid. The position in the shell of the
fluid communication inlet and outlet for the second fluid is found
at points located, according to the axial or longitudinal direction
X-X', between the end baffles, i.e., the baffles between which the
bundle of conduits and the bypass conduit extend. The second fluid
is thus circulated through the inside of the space located in the
shell, outside of both the conduits of the bundle of conduits and
the bypass conduit, and between the baffles. [0023] a first fluid
communication inlet/outlet arranged at one of the ends of the
bundle of conduits and of the bypass conduit, and a second fluid
communication inlet/outlet arranged at the opposite end of the
bundle of conduits and of the bypass conduit, both the fluid
communication inlet/outlet giving access to the first fluid through
the bundle of conduits, through the bypass conduit or through
both.
[0024] In most of the examples, the ends of the shell either
incorporate manifolds configured as closure parts for closing the
ends of the tubular shell which form a cavity, or they prolong the
tubular body of the shell leaving a space to form an intermediate
chamber. In this second case, in the embodiments that will be
described below, the chamber is closed by an end cover. Both the
closure parts and the covers are also stamped parts. [0025] where
the tubular sheet metal shell extends longitudinally beyond the
second baffle giving rise to a chamber such that said chamber
comprises a valve that can be actuated from outside the chamber and
is adapted to at least close the bypass conduit, and where said
valve comprises a shaft attached to the sheet metal shell and
capable of rotating with respect to said shell, prolonging into the
chamber where said shaft comprises a sheet metal flap adapted to
sit on the perimetral edge of the end of the bypass conduit for
closing same.
[0026] According to some embodiments, the tubular shell has one or
more steps after which the tubular body has a larger diameter.
These steps will also be identified in this description as
expansions where the term expansion must be interpreted as a change
in diameter. The change in diameter being from larger to smaller or
vice versa, from smaller to larger, depends on the chosen
direction. In all the examples, the use of the term expansion in
reference to the step must be interpreted in the broadest sense
indicated, i.e., a change in diameter that gives rise to a step
formation. When the term diameter is used, it must be interpreted
as a characteristic dimension, i.e., if the section is a circular
section, it is clearly the diameter of the circumference and if the
section is a square section or a section having any other
configuration, it is possible to establish a dimension that
considers the change of said section in the step formation.
[0027] According to one embodiment, this stepped shape is generated
by stamping. The step allows housing one of the baffles,
determining the position of the baffle inside the shell. The
position thereof will be described in later examples. This solution
is the preferred solution of the examples in which an intermediate
chamber is defined from the baffle to the closure cover.
[0028] As indicated, according to some embodiments, said one or
more steps give rise to a smaller diameter of the tubular body. The
step allows quick assembly since it automatically establishes
correct positioning of the parts that are fitted therein during
assembly.
[0029] According to some embodiments, the tubular shell has the
same diameter along its length, reducing shell manufacturing
costs.
[0030] Use of the expression closure cover or manifold is primarily
determined based on whether the stamping operation gives rise to a
flat plate or whether the concavity generates an inner cavity, and
therefore an intermediate chamber. The closure cover, the manifold
or both are the closure means for closing the ends of the tubular
shell.
[0031] The valve is also primarily manufactured in sheet metal.
According to embodiments, the base is configured in sheet metal
with the curvature of the outer surface of the shell. This base is
preferably attached to the shell by brazing. Other welding
techniques such as laser welding are other possible modes of
operation in each of the possible embodiments of the invention. The
support of the shaft of the valve emerges from the base, prolonging
into the chamber. In the embodiments, the shaft is arranged in
cantilever fashion, extending according to a transverse projection
of the heat exchanger to one side of the end of the bypass conduit.
The rotation of the shaft therefore gives rise to the movement of a
flap integral with the shaft, such that in one of its positions,
the flap sits on the perimetral edge of the end of the bypass
conduit for closing same. In this closed position, the first fluid
completely goes through the bundle of tubes, and in any other
position, the passage of the first fluid through the bypass conduit
is allowed. According to other embodiments, the shaft may not be
arranged in cantilever fashion and may have a support capable of
rotating with respect to two points of the shell such that the
shaft extends into the chamber between both points, thereby
increasing robustness. Additionally, the use of a cantilever
configuration allows reducing the parameters involved in the
correct position of the flap integral with the shaft, allowing
better positioning with respect to the closure seat.
[0032] Among other advantages, the use of the perimetral edge of
the bypass conduit allows doing away with the machining of seats
made of molten parts. Nevertheless, this perimetral edge could be
formed by additional tubular bodies prolonging the bypass conduit
according to a complex configuration of more than one part, for
example the tubular body that serves as an insulator so that the
bypass conduit does not transfer heat to the first fluid. According
to some embodiments, the flap of the valve is also obtained from
stamped sheet metal, with a suitable convex surface so that said
convex surface partially enters the bypass conduit, and where this
convex shape provides greater stiffness to the flap.
DESCRIPTION OF THE DRAWINGS
[0033] The foregoing and other advantages and features of the
invention will be better understood from the following detailed
description of a preferred embodiment given only by way of
illustrative and non-limiting example in reference to the attached
drawings.
[0034] FIG. 1 shows an exploded perspective view of a first
embodiment of the invention. In this embodiment, the valve allows
closing only the bypass conduit.
[0035] FIG. 2 shows a perspective view of the same embodiment as in
FIG. 1 with the parts assembled except for the end cover that gives
access to the inside of the chamber.
[0036] FIG. 3 shows an elevational view of the same embodiment as
in the preceding figures, indicating section A-A shown to the left.
Cross-section A-A goes through the shaft of the valve.
[0037] FIGS. 4A-4B show an elevational view of the same embodiment
as in the preceding figures according to a longitudinal section. A
first position leaving the bypass conduit open and a second
position leaving the bypass conduit closed are shown in these two
sections.
[0038] FIG. 5 shows an exploded perspective view of a second
embodiment of the invention. In this embodiment, a stamped sheet
metal part which allows closing the tubes of the bundle of tubes
with a particular configuration allowing the passage of the bypass
conduit therethrough, is incorporated. The particular configuration
of this part allows the valve to be able to close both the passage
to the bypass conduit and the passage to the tubes of the bundle of
tubes.
[0039] FIG. 6 shows a perspective view of the same second
embodiment with the parts assembled except for the end cover and
the assembly of parts giving rise to the valve. These parts are
shown in an exploded view.
[0040] FIGS. 7A-7B show an elevation of the same second embodiment
according to a longitudinal section. A first position closing the
tubes of the bundle of tubes and leaving the bypass conduit open,
and a second position closing the bypass conduit and leaving the
passage through the tubes of the bundle of tubes open, are shown in
these two sections.
[0041] FIG. 8 shows an exploded partial perspective view of a third
embodiment of the invention. This perspective view shows all the
components in their final position and only those components
associated with the valve and the closure cover are shown in an
exploded view. The seat of the valve has been modified in this
embodiment, where the shaft does not go through a perforation but
rather through a groove. This configurative change allows quicker
assembly of the components.
[0042] FIG. 9 shows a perspective view of the same third example
where a partial section has been made which allows showing the
valve in its final position and the configuration thereof.
DETAILED DESCRIPTION
[0043] According to the first inventive aspect, the present
invention is a device for heat exchange between a first fluid and a
second fluid. The embodiments show three EGR exchangers, where the
first fluid is the recirculated gas which is cooled by transferring
heat to a second fluid which is a coolant in the three
examples.
[0044] In the three embodiments, the heat exchanger has a bypass
conduit as well as a closure valve for closing the bypass conduit.
The components of the heat exchanger and most of the components of
the valve are made of sheet metal formed by stamping.
[0045] FIG. 1 shows a first embodiment having a simple
construction. According to this embodiment, the main body of the
heat exchanger is formed by a sheet metal shell (1) having a
tubular configuration. The sheet metal shell (1) has an expansion
step (1.1) at one of its ends, the end shown to the right of the
drawing, giving rise to an end portion having a larger
diameter.
[0046] This step (1.1) defines an end portion having a larger
diameter which establishes a chamber (C) when it is closed by means
of a cover (9).
[0047] The opposite end of the sheet metal shell (1) also has a
ring-shaped step (1.7) at the end. A first sheet metal baffle (3)
and a second sheet metal baffle (4) are housed in both the
expansion step (1.1) and the ring-shaped step (1.7).
[0048] The first and second sheet metal baffles (3, 4) are
configured according to a main flat plate with a perimetral edge
generated by pressing, which gives rise to a cylindrical perimetral
seat that fits in the inner wall of the sheet metal shell (1),
being supported on the corresponding step (1.1, 1.7).
[0049] The flat area of the first and second sheet metal baffles
(3, 4) show a perforation (3.1, 4.1) for a bypass conduit (5) and a
plurality of perforations (3.2, 4.2) having a smaller diameter for
each of the conduits of a bundle of conduits. Given that the
conduits are tubes in this embodiment, they will be referred to as
tubes of a bundle of tubes (2) hereinafter and for the examples
described based on the drawings.
[0050] Both the bypass conduit (5) and the bundle of tubes (2)
extend from the first baffle (3) to the second baffle (4), their
ends being housed in the corresponding perforation (3.1, 3.2, 4.1,
4.2). Each end of each tube (2) and of the bypass conduit (5) is
perimetrically attached to the also perimetral edge of the
corresponding perforation (3.1, 3.2, 4.1, 4.2) by means of
brazing.
[0051] The bundle of tubes (2) is housed inside the sheet metal
shell (1), giving rise to the exchange surface between the gas to
be cooled circulating through the inside of said bundle of tubes
(2) and the coolant circulating through the intermediate space
between the bundle of tubes (2) and the inner wall of the sheet
metal shell (1).
[0052] In this embodiment, the bypass conduit (5) is also in
contact with the coolant. Nevertheless, the bypass conduit (5) has
a much larger diameter than the tubes of the bundle of tubes (2),
such that the ratio between the exchange surface and the flow is
much lower in this case, giving rise to a much lower degree of heat
transfer. Diverting gas flow through the bypass conduit (5)
involves drastically reducing the heat removed from the gas
flow.
[0053] The bundle of tubes (2), the bypass conduit (5) and the main
axis of the tubular body of the sheet metal shell (1) extend in the
same direction referred to as the axial or longitudinal direction
X-X'.
[0054] The inside of the sheet metal shell (1) located between the
first baffle (3) and the second baffle (4) according to
longitudinal direction X-X' is the portion containing the coolant.
The fluid communication inlet (1.4) for the coolant is located
close to the second baffle (4), and the fluid communication outlet
(1.5) for the coolant is located close to the first baffle (3).
Depending on whether the exchanger operates in cocurrent or
countercurrent mode, the inlet and the outlet (1.4, 1.5) are
interchangeable. According to the perspective view and the view
point selected for depicting FIG. 1, both fluid communication inlet
and outlet (1.4, 1.5) for the coolant are concealed by the sheet
metal shell (1), only a small portion of the inlet (1.4) being seen
through the right end of the sheet metal shell (1) where the
chamber (C) is located. Although the exploded perspective view
shows the inlet (1.4) through the visual access allowed by the
chamber (C), this chamber (C) is not in fluid communication with
the inlet (1.4).
[0055] The end of the heat exchanger arranged on the side opposite
the chamber (C) is closed by a manifold (10), which is stamped in
sheet metal in this embodiment. The manifold (10) forms a chamber
that receives or distributes, according to whether the exchanger
operates in a cocurrent or countercurrent mode, the exhaust gas
circulating through the tubes of the bundle of tubes (2) or the
bypass conduit (5). The manifold (10) has a first fluid
communication inlet/outlet (10.1) communicated with the engine
exhaust system. A second fluid communication inlet/outlet (1.6) for
the exhaust gas is located laterally at the other end of the sheet
metal shell (1), giving rise to the flow of said exhaust gas
through the heat exchanger.
[0056] Both the tubes of the bundle of tubes (2) and the bypass
conduit (5) open into the chamber (C) at the end of the heat
exchanger arranged on the side of the chamber (C). The chamber (C)
is defined according to longitudinal direction X-X' between the
second baffle (4) and the cover (9) located at the end of the sheet
metal shell (1).
[0057] The heat exchanger transfers heat from the gas to the
coolant through the bundle of tubes (2). For the heat exchanger to
operate in this manner, a valve closes the bypass conduit (5) so
that the flow between the chamber (C) and the manifold (10) located
at the end opposite completely goes through the bundle of tubes (2)
and not through the bypass conduit (5).
[0058] In view of FIGS. 1 and 2, the valve of this embodiment is
formed by an actuator, not shown in this FIG. 1, acting on a
connecting rod (6.3) transforming axial movement of the actuator
into rotational movement about the rotating shaft (6) where the
connecting rod (6.3) is assembled.
[0059] The rotating shaft (6) is housed in a support (8) that
retains said shaft axially but allows its rotational movement. This
support (8) is attached to a base (7) which in this embodiment is
formed by a sheet metal portion curved according to a cylindrical
sector, adapted to be supported on the surface of the sheet metal
shell (1) of the exchanger.
[0060] In this embodiment, the attachment of the shaft (6) to the
sheet metal shell (1) maintaining the rotation, the primary degree
of freedom allowed to the shaft (6), is carried out in this
embodiment by means of the interposition of a support (8) which is
in turn attached to the base (7). Nevertheless, in all the
embodiments of the invention, it is possible to link the shaft (6)
to the shell (1) in another way. Depending on the stiffness of the
attachment, the support (8) can be directly brazed onto the sheet
metal shell (1) or be attached to a base (7) which is in turn
attached to the shell (1). The presence of the base (7) allows
increasing stiffness of the attachment and also allows
incorporating extensions offering a fixing seat to the actuator,
for example.
[0061] Continuing with the description of the first embodiment, the
rotating shaft (6) extends from the outside, where it is linked to
the connecting rod (6.3), to the inside of the chamber (C) going
through a perforation (1.2) for the passage of the rotating shaft
(6), where it is prolonged a specific distance in cantilever
fashion. As shown in FIG. 3, in the cross-section going through the
rotating shaft (6), the geometric axis of said rotating shaft (6)
is located transverse to the bypass conduit (5) and spaced from
said conduit (5).
[0062] There is a flap (6.1) at the cantilevered end such that the
rotation of the rotating shaft (6) causes the former to rotate,
said flap (6.1) being positioned on the perimetral edge of the
bypass conduit (5) and therefore giving rise to the closure of said
conduit. The rotation of the shaft (6) in the opposite direction
completely or partially opens the passage through the bypass
conduit (5) according to the opening angle.
[0063] In view FIGS. 4A and 4B, the described valve allows closing
the bypass conduit (5) so that gas flow goes through the bundle of
tubes (2) completely. The opening of the bypass valve leaves the
bypass conduit (5) open but does not prevent passage through the
bundle of tubes (2). Nevertheless, the smaller diameter of the
tubes of the bundle of tubes (2) confers greater resistance against
passage than the bypass conduit (5) does and therefore favors
passage to a greater extent through the bypass conduit (5). In this
case, passage of a large portion of the flow through the bypass
conduit (5), which has a much lower degree of heat transfer than
the bundle of tubes (2), gives rise to less cooling of the gas.
[0064] FIG. 5 shows a second embodiment according to an exploded
perspective view where most of the components are common components
with respect to the first embodiment, therefore only the
differences shown in this second example with respect to the first
embodiment are addressed in this description.
[0065] In this second embodiment, instead of being arranged in the
wall of the sheet metal shell (1) coinciding with the chamber (C)
as indicated with reference 1.6, the second fluid communication
inlet/outlet for the gas in this embodiment is located in the cover
(9), this fluid communication inlet/outlet (9.1) being arranged in
the center of said cover (9).
[0066] As a first improvement, in this embodiment it is possible to
completely close the bypass conduit (5) so that the flow goes
through the bundle of tubes (2) as well as the passage through the
bundle of tubes (2) so that the flow goes through the bypass
conduit (5) completely. The possibility of completely closing the
passage of flow through the bundle of tubes (2) allows reducing
minimum cooling of the device to a greater extent, for example, for
applications during engine startup when it is cold.
[0067] To achieve the complete closure of the passage of flow
through the bundle of tubes (2), the device according to this
embodiment incorporates a stamped sheet metal part (11) housed in
the chamber (C). This stamped part (11) is formed by a metal sheet
perimetrically fitted to the inner wall of the chamber (C), in this
case coinciding with the inner wall of the portion of sheet metal
shell (1) closing the chamber (C). The part establishes a partition
wall in the chamber (C) except for two openings, a first opening
(11.1) and a second opening (11.2). The partition wall in turn
gives rise to two sub-chambers, an inner sub-chamber (Ci) located
between the second baffle (4) and the stamped sheet metal part
(11), and an outer sub-chamber (Co) located between the stamped
sheet metal part (11) and the cover (9).
[0068] The first opening (11.1) establishes the passage from the
side where the valve is located and the side where access to the
tubes of the bundle of tubes (2) is located. This first opening
(11.1) has a tube end-shaped termination, such that its perimetral
edge establishes a seat for a flap (6.2). The final tube end shape
is configured by stamping.
[0069] The second opening (11.2) is also tube end-shaped and
receives the end of the bypass conduit (5). According to this
embodiment, the bypass conduit (5) is prolonged beyond the second
baffle (4) until reaching the stamped sheet metal part (11).
Therefore, the inside of the bypass conduit (5) and the inner
sub-chamber (Ci) are not in fluid communication. In this
embodiment, the bypass conduit (5) is internally housed in the
second opening (11.2) until going beyond same such that the
perimetral edge of its end continues to be the seat for the flap
(6.1) of the valve.
[0070] In this embodiment, therefore, there are two flaps, a first
flap (6.1) closing the passage through the bypass conduit (5) and a
second flap (6.2) closing the passage through the bundle of tubes
(2).
[0071] According to another alternative embodiment, the bypass
conduit (5) is not prolonged beyond the second opening (11.2) of
the stamped sheet metal part (11) but rather opens into said
opening (11.2). The seat of the first flap (6.1) is therefore
located directly on the perimetral edge of the tube end-shaped
second opening (11.2).
[0072] Another improvement of the second embodiment consists of the
bypass conduit (5) in turn being formed by two tubes, an inner tube
(5a) and an outer tube (5b). The outer tube (5b) is in contact with
the coolant. The inner tube (5a) is where the gas flow circulates
when the bypass conduit (5) is open. Given that there is a chamber
or space between the inner tube (5a) and the outer tube (5b) having
a larger diameter, a thermal bather reducing the cooling of the gas
going through the bypass conduit (5) is established.
[0073] In this embodiment, the outer tube (5b) extends from the
first baffle (3) to the second baffle (4), and the inner tube (5a)
is prolonged until reaching the stamped sheet metal part (11). In
this embodiment, the two ends of the outer tube (5b) are expanded
to assure the attachment with the baffles (3, 4).
[0074] The section shown in FIGS. 7A and 7B shows both the
structure of the bypass conduit (5), in turn formed by two tubes
(5a, 5b), and the arrangement of the stamped sheet metal part (11)
with its two openings (11.1, 11.2).
[0075] These same drawings show the valve with two flaps (6.1, 6.2)
formed from the same metal sheet by stamping. The flaps (6.1, 6.2)
are positioned 90 degrees with respect to one another about the
same rotating shaft (6), such that a 90 degree rotation is
established between two end positions; a first position closing the
bypass conduit (5) and a second position closing the bundle of
tubes (2) by means of closing the first opening (11.1).
[0076] In one embodiment, the two flaps (6.1, 6.2) are independent
from one another, both being attached to the rotating shaft
(6).
[0077] In one embodiment, the angle according to which the two
flaps (6.1, 6.2) are positioned depends on the valve actuation
system, and the rotation of the shaft between the two end positions
will depend on the angle formed between both (6.1, 6.2). Said angle
usually depends on the actuation mechanism and its travel.
[0078] FIG. 6 shows a perspective view where only the parts
associated with the valve are shown in an exploded view.
Particularly, the rotating shaft (6) with the two flaps (6.1, 6.2)
attached to said rotating shaft (6) is shown in the intermediate
assembly position. In other words, the rotating shaft (6) is
installed through the inside of the chamber (C) once all the parts
are brazed, particularly the stamped sheet metal part (11) shown
towards the back of the outer chamber (Co). The rotating shaft (6)
is introduced in the outer sub-chamber (Co), and goes through the
perforation (1.2) until it is attached to the support (8) of the
rotating shaft (6).
[0079] According to this embodiment, the rotating shaft (6) is also
arranged in cantilever fashion, like what has been described in the
first embodiment.
[0080] FIGS. 8 and 9 show a third embodiment. In this third
embodiment, a structure such as that described in the second
embodiment except for some dimensional changes and the differences
highlighted below, is used.
[0081] The most significant difference between the third embodiment
and the second embodiment is the substitution of the perforation
(1.2) for the passage of the rotating shaft (6) with a groove (1.3)
reaching the edge of the end of the sheet metal shell (1) where the
chamber (C), also the outer chamber (Co) in this case, is
located.
[0082] Although the perforation (1.2) requires assembling the
rotating shaft (6) from inside the chamber (C) until reaching the
support (8) located outside the sheet metal shell (1), the groove
(1.3) allows being able to assemble the rotating shaft (6) first on
the support (8), this support (8) in turn being previously placed
on the base (7), and to insert the entire assembly from the front.
In other words, the assembly of the rotating shaft (6) previously
located on the support (8) and the base (7) is carried out by
introducing the rotating shaft (6) through the groove (1.3) until
it reaches its final position. The base (7) is brazed onto the
sheet metal shell (1) in this position.
[0083] The solution of incorporating the rotating shaft (6) through
the groove (1.3) is also applicable to other embodiments, for
example the first embodiment.
[0084] In addition to facilitating assembly, the configuration
according to this embodiment allows positioning the rotating shaft
(6) so that the seat or seats of the flaps (6.1, 6.2) is correct
and welding the base (7) in this position once said shaft is
positioned.
[0085] Openings (11.1, 11.2) and flaps (6.1, 6.2) with an elongated
shape instead of a circular shape have been configured in the third
embodiment only as a constructive detail. This embodiment shows
both the linear actuator (13) and the actuation rod (12) reaching
the connecting rod (6.3) which are not shown in the graphical
depictions of other embodiments.
[0086] Likewise, the second fluid communication inlet/outlet (1.6)
is again placed in the wall of the sheet metal shell (1) as
described in the first embodiment.
* * * * *