U.S. patent application number 11/996400 was filed with the patent office on 2008-08-28 for heat exchanger.
Invention is credited to Peter Geskes, Ulrich Maucher, Jens Richter, Jens Ruckwied.
Application Number | 20080202735 11/996400 |
Document ID | / |
Family ID | 37102470 |
Filed Date | 2008-08-28 |
United States Patent
Application |
20080202735 |
Kind Code |
A1 |
Geskes; Peter ; et
al. |
August 28, 2008 |
Heat Exchanger
Abstract
The invention relates to a heat exchanger (1) with flow channels
(3), which can be flowed through from a common first inlet to a
common first outlet by a first fluid, comprising a housing (2),
which accommodates the flow channels (3) and which can be flowed
through by a second fluid from a second inlet area to a second
outlet area. The flow channels (3) have a flat cross-section as
well as longitudinal sides (3a) and are flow-connected to one
another. The invention provides that the longitudinal sides (3a) of
the flow channels (3) are integrally connected to the housing (2),
particularly by soldering.
Inventors: |
Geskes; Peter; (Ostfildern,
DE) ; Maucher; Ulrich; (Korntal-Munchingen, DE)
; Richter; Jens; (Grossbottwar, DE) ; Ruckwied;
Jens; (Stuttgart, DE) |
Correspondence
Address: |
FOLEY AND LARDNER LLP;SUITE 500
3000 K STREET NW
WASHINGTON
DC
20007
US
|
Family ID: |
37102470 |
Appl. No.: |
11/996400 |
Filed: |
July 17, 2006 |
PCT Filed: |
July 17, 2006 |
PCT NO: |
PCT/EP2006/006997 |
371 Date: |
March 17, 2008 |
Current U.S.
Class: |
165/166 ;
165/157 |
Current CPC
Class: |
F28D 2021/0084 20130101;
F28D 2021/0096 20130101; F28D 2021/0089 20130101; F28D 21/0003
20130101; F28D 9/0043 20130101; F28F 9/0265 20130101; F28D
2021/0085 20130101; F28F 2250/102 20130101; F28D 9/0006
20130101 |
Class at
Publication: |
165/166 ;
165/157 |
International
Class: |
F28D 9/00 20060101
F28D009/00; F28F 3/12 20060101 F28F003/12 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 19, 2005 |
DE |
10 2005 034 137.3 |
Mar 24, 2006 |
DE |
10 2006 014 187.3 |
Claims
1. A heat exchanger having flow channels through which a first
fluid can flow from a common first inlet to a common first outlet,
having a housing which holds the flow channels in it and through
which a second fluid, which differs from the first fluid
(alternatively: and a second fluid different from the first fluid),
can flow from a second inlet area to a second outlet area, with the
flow channels having a flat cross section and longitudinal faces,
wherein the longitudinal faces of the flow channels are integrally
connected to the housing.
2. The heat exchanger as claimed in claim 1, wherein the flow
channels are integrally connected to the housing essentially over
the entire length of the longitudinal faces.
3. The heat exchanger as claimed in claim 1, wherein flow channels
are in the form of plate pairs and, in conjunction with the
housing, form channels for the second fluid to pass through.
4. The heat exchanger as claimed in claim 1, wherein the flow
channels and the channels for the second fluid to pass through are
essentially accommodated in their entirety by the housing.
5. The heat exchanger as claimed in claim 1, wherein at least one
flow channel for the first fluid is formed between a cover and a
lower plate which is adjacent to the cover.
6. The heat exchanger as claimed in claim 1, wherein at least one
flow channel for the first fluid is formed between an upper plate,
which is adjacent to a base section of a housing shell, and between
the base section of the housing shell.
7. The heat exchanger as claimed in claim 1, wherein the plate
pairs have a lower plate and an upper plate which are connected to
one another at the rim by a fold.
8. The heat exchanger as claimed in claim 1, wherein at least one
inlet flow channel and/or at least one outlet flow channel run/runs
transversely through the plate pairs.
9. The heat exchanger as claimed in claim 1, wherein the plate
pairs have at least one depression or at least one protrusion.
10. The heat exchanger as claimed in claim 1, wherein the
protrusion on a plate pair extends to an adjacent plate pair,
touches them, and is integrally connected to the adjacent plate
pair.
11. The heat exchanger as claimed in claim 1, wherein the
protrusion is incorporated in the upper plate and the protrusion
has an upper plate annular surface which touches a lower plate
annular surface of the lower plate of an adjacent plate pair and,
is integrally connected to the lower plate annular surface by.
12. The heat exchanger as claimed in claim 1, wherein a protrusion
is incorporated in the lower plate and the protrusion has a lower
plate annular surface which touches an upper plate annular surface
of the upper plate of an adjacent plate pair and is integrally
connected to the upper plate annular surface soldering.
13. The heat exchanger as claimed in claim 1, wherein the flow
channels are stacked.
14. The heat exchanger as claimed in claim 1, wherein the cover is
placed on the housing or the housing shells in a stacking
direction.
15. The heat exchanger as claimed in claim 1, wherein the upper
plate of a plate pair has an upper plate rim surface, and the
associated lower plate has a lower plate rim surface, with the
upper plate rim surface corresponding to the lower plate rim
surface and being integrally connected.
16. The heat exchanger as claimed in claim 1, wherein the
longitudinal faces of two plate pairs which form a flow channel
clasp one another at least in places, in particular over the entire
plate length, and in that, in particular, the longitudinal face
which touches the housing clasps the longitudinal face of an
adjacent plate, in particular the other plate of the respective
plate pair.
17. The heat exchanger as claimed in claim 1, wherein broader faces
of two plate pairs which form a flow channel clasp one another at
least in places, in particular over the entire plate width.
18. The heat exchanger as claimed in claim 1, wherein the plate
pairs have turbulence-generating devices, in particular turbulence
inserts or stamped-in structure elements which are arranged in the
flow channels.
19. The heat exchanger as claimed in claim 9, wherein the
protrusions are conical.
20. The heat exchanger as claimed in claim 19, wherein the
protrusions are streamlined in the direction of the longitudinal
faces, in particular with an elongated or elliptical cross
section.
21. The heat exchanger as claimed in claim 1, wherein
turbulence-generating devices, comprising turbulence inserts or
structure elements formed from the plate pairs, are arranged
between flow channels and/or in the channels for the second fluid
to pass through.
22. The heat exchanger as claimed in claim 1, wherein the plate
pairs are connected to the housing via their longitudinal-face
folded connections.
23. The heat exchanger as claimed in claim 1, wherein the inlet
area of the housing is arranged in front of the plate pairs in the
flow direction of the second fluid.
24. The heat exchanger as claimed in claim 1, wherein the outlet
area of the housing is arranged behind the plate pairs in the flow
direction of the second fluid.
25. The heat exchanger as claimed in claim 1, wherein the second
fluid can flow around the plate pairs essentially parallel to their
longitudinal faces.
26. The heat exchanger as claimed in claim 1, wherein the fold on
the longitudinal face is formed by rims of an upper plate and lower
plate that are bent in the same sense, and forms a contact surface
for the housing.
27. The heat exchanger as claimed in claim 1, wherein the fold on
the longitudinal face is formed by rims of an upper plate and lower
plate that are bent in opposite senses, and forms a contact surface
for the housing.
28. The heat exchanger as claimed in claim 1, wherein the plate
pairs have side channels for the first fluid on the longitudinal
face in the area of the housing walls.
29. The heat exchanger as claimed in claim 28, wherein the side
channels are in the form of an extension of the flow cross section
of the plate pairs.
30. The heat exchanger as claimed in claim 29, wherein the
extension has a channel height which corresponds essentially to the
distance between the plate pairs.
31. The heat exchanger as claimed in claim 1, wherein the plate
pairs have a flow cross section with a channel width b, and the
housing walls are separated by a distance w, where b<w and
material bridges are arranged between the flow cross sections and
the housing wall, in particular formed from a lower plate and/or an
upper plate.
32. The heat exchanger as claimed in claim 1, wherein the housing
is formed in at least two parts, and has a housing shell as well as
a cover.
33. The heat exchanger as claimed in claim 1, wherein the inlet
area of the housing has an inlet connecting stub, which is arranged
in the housing shell or in the cover.
34. The heat exchanger as claimed in claim 1, wherein the outlet
area of the housing has an outlet connecting stub, which is
arranged in the housing shell or in the cover.
35. The heat exchanger as claimed in claim 1, wherein the housing
has an inlet connecting stub and an outlet connecting stub for the
first fluid.
36. The heat exchanger as claimed in claim 1, wherein the inlet and
outlet connecting stubs for the first fluid are arranged in the
cover or in the housing shell.
37. The heat exchanger as claimed in claim 1, wherein the inlet
and/or the outlet connecting stubs have longitudinal axes which are
at an angle to the plate pairs.
38. The heat exchanger as claimed in claim 1, wherein the heat
exchanger has a bypass.
39. The heat exchanger as claimed in claim 1, wherein a bypass
channel for the second fluid is arranged within the housing and
parallel to the plate pairs.
40. The heat exchanger as claimed in claim 1, wherein a separating
wall is arranged in the inlet area for the second fluid.
41. The heat exchanger as claimed in claim 1, wherein a separating
wall is arranged in the outlet area for the second fluid.
42. The heat exchanger as claimed in claim 1, wherein the heat
exchanger contains at least one non-return valve, which is
preferably integrated in the housing and is located in the outlet
area.
43. The heat exchanger as claimed in claim 1, wherein the bypass
channel is arranged above or below the plate pairs.
44. The heat exchanger as claimed in claim 1, wherein the bypass
channel is in the form of a bypass tube which can be inserted into
the housing.
45. The heat exchanger as claimed in claim 1, wherein the bypass
channel is thermally insulated from the flow channels and/or from
the channels for the second fluid to pass through.
46. The heat exchanger as claimed in claim 1, wherein the bypass
channel is essentially arranged at a distance from the flow
channels and/or from the channels for the second fluid to pass
through.
47. The heat exchanger as claimed in claim 1, wherein the bypass
channel and/or a flow channel which is adjacent to the bypass
channel and/or the channel for the second fluid to pass through
have or has projections by means of which the flow channels or the
channels for the second fluid to pass through are preferably
essentially separated from the bypass tube.
48. The heat exchanger as claimed in claim 1, wherein the bypass
channel comprises at least one partial element which is preferably
in the form of an open profile and particularly advantageously is
in the form of a U-profile or half-tube.
49. The heat exchanger as claimed in claim 1, wherein the bypass
channel comprises two tube halves.
50. The heat exchanger as claimed in claim 1, wherein the bypass
channel has at least one longitudinal separating wall.
51. The heat exchanger as claimed in claim 1, wherein a bypass flap
can be integrated in the inlet or outlet area of the housing.
52. The heat exchanger as claimed in claim 1, wherein the inlet
area has two separate inlet connecting stubs as well as one
separating wall.
53. The heat exchanger as claimed in claim 1, wherein the plate
pairs form a pack through which the second fluid flows on two
paths.
54. The heat exchanger as claimed in claim 1, wherein an inlet
chamber and an outlet chamber are arranged on one side of the plate
pack and a deflection chamber for the second fluid is arranged on
the other side of the plate pack.
55. The heat exchanger as claimed in claim 39, wherein the bypass
is integrated in the housing.
56. The heat exchanger as claimed in claim 39, wherein the bypass
is integrated in the cover.
57. The heat exchanger as claimed in claim 1, wherein the heat
exchanger has at least one flap.
58. The heat exchanger as claimed in claim 1, wherein the flap is
arranged in the inlet area or in the outlet area.
59. The heat exchanger as claimed in claim 1, wherein the heat
exchanger has at least one bypass valve.
60. The heat exchanger as claimed in claim 59, wherein the bypass
valve is integrated in the housing.
61. The heat exchanger as claimed in claim 59, wherein the bypass
valve is arranged in the inlet area and/or in the outlet area.
62. The heat exchanger as claimed in claim 59, wherein the bypass
valve is a combination valve.
63. The heat exchanger as claimed in claim 60, wherein the
integrated bypass has a separating wall which can pivot and by
means of which the inlet connecting stub and the outlet connecting
stub can be short-circuited.
64. The heat exchanger as claimed in claim 1, wherein the first
fluid is a liquid coolant, in particular the coolant from the
cooling circuit of an internal combustion engine for a motor
vehicle, and the second fluid is fed-back exhaust gas from the
internal combustion engine.
65. The heat exchanger as claimed in claim 1, wherein the first
fluid is air, and the second fluid is fed-back exhaust gas from an
internal combustion engine for a motor vehicle.
66. The heat exchanger as claimed in claim 1, wherein the heat
exchanger has an oxidation catalytic converter.
67. The heat exchanger as claimed in claim 1, wherein the plate
pack is preceded by the oxidation catalytic converter.
68. The heat exchanger as claimed in claim 1, wherein the first
fluid is a liquid coolant, in particular the coolant in the cooling
circuit of an internal combustion engine for a motor vehicle, and
the second fluid is boost air which can be supplied to the internal
combustion engine.
69. The heat exchanger as claimed in claim 1, wherein the first
fluid is air and the second fluid is boost air which can be
supplied to an internal combustion engine for a motor vehicle.
70. The use of the heat exchanger as claimed in claim 1, comprising
an exhaust-gas cooler in an exhaust-gas feedback system for an
internal combustion engine for a motor vehicle or as a heater for
heating the interior of a motor vehicle.
71. An internal combustion engine for a motor vehicle comprising a
heat exchanger as claimed in claim 1, employed as a boost-air
cooler for direct or indirect cooling of boost air for the internal
combustion engine.
72. A motor vehicle comprising a heat exchanger as claimed in claim
1, employed as an oil cooler for cooling engine oil for an internal
combustion engine or for cooling gearbox oil for the motor vehicle
by means of a liquid coolant.
73. A climate control system for a motor vehicle comprising a heat
exchanger as claimed in claim 1, employed as a coolant condenser in
a coolant circuit of a climate-control system.
74. A climate control system for a motor vehicle comprising a heat
exchanger as claimed in claim 1, employed as a coolant exhaust-gas
cooler in a coolant circuit of a climate-control system.
75. A climate control system for a motor vehicle comprising a heat
exchanger as claimed in claim 1, employed as a coolant vaporizer in
a coolant circuit of the climate-control system.
Description
[0001] The invention relates to a heat exchanger as claimed in the
precharacterizing clause of patent claim 1, known from DE 100 60
102 A1.
[0002] US 2003/0010479 A1 discloses a heat exchanger which can be
used as an exhaust-gas cooler in an exhaust-gas feedback system.
Exhaust-gas tubes are arranged in a housing through which liquid
coolant in the cooling circuit of an internal combustion engine
flows and are held at the end in tube bases which are themselves
connected to the housing. The exhaust gas is supplied to the
exhaust-gas cooler via a diffusor, then flows through the
exhaust-gas tubes around which the coolant flows, and emerges from
the cooler via an exhaust-gas connecting stub. All the parts of the
exhaust-gas cooler are soldered to one another. This design with
tube bases in which the tube ends are held has the disadvantage
that the tubes are fixed in the tube bases during the soldering
process and therefore cannot move towards one another during
soldering and during melting of the solder layer which, inter alia,
also has a disadvantageous effect on the soldering of the
turbulence inserts to the tube inner walls. This disadvantage is
avoided by systems without tube bases, as shown by the following
example:
[0003] DE 100 60 102 A1 discloses a heat exchanger which can
likewise be used as an exhaust-gas cooler in an exhaust-gas
feedback system. In this case, fed-back exhaust gas is cooled by
coolant which is taken from the cooling circuit of the internal
combustion engine for the motor vehicle. The known exhaust-gas
cooler has a housing which is essentially in two parts and in which
a heat sink is arranged, through whose primary side coolant can
flow and which comprises a multiplicity of flat small tubes and
through whose secondary side exhaust gas flows. In this case, the
exhaust gas is passed through the housing in a relatively straight
line, that is to say without any significant direction changes. The
coolant is input and output at right angles to the flat small
tubes, thus resulting in 90.degree. direction changes in each case.
In order to improve the heat transfer between the exhaust gas and
the coolant, so-called turbulence sheets are arranged between the
flat small tubes. The entire exhaust-gas cooler comprising the
housing, small tubes and turbulence sheets is produced by "integral
soldering".
[0004] The application subject matter of DE 100 60 102 A1 results
from the prior art as shown in FIG. 9, which relates to an
exhaust-gas heat exchanger without a housing, with flat exhaust-gas
tubes being formed from plates whose fold has angled raised rim
strips on the longitudinal faces, which are soldered to adjacent
rim strips to form a housing wall. This has the disadvantage that
there are a multiplicity of solder points, each of which is
intrinsically subject to the risk of leakage, and thus of
exhaust-gas leakage. The application subject matter of DE 100 60
102 A1 has the disadvantage that the exhaust-gas flow acts directly
on the housing walls which are therefore heated to a temperature
which is incompatible with the area surrounding the built-in
exhaust-gas cooler, for example the engine bay of a motor
vehicle.
[0005] One object of the present invention is to design a heat
exchanger of the type mentioned in the introduction on the one hand
to be suitable for joining techniques, in particular soldering,
welding, adhesive bonding etc., and on the other hand to keep its
external temperature low when using hot media to be cooled.
[0006] This object is achieved by the features of patent claim
1.
[0007] The invention provides that the flow channels, which are
preferably in the form of plate pairs, are preferably integrally
connected on the longitudinal faces to the walls of the housing,
that is to say by soldering, welding, adhesive bonding etc. The
plate pairs are placed in layers on top of one another to form a
pack, and are connected to one another for flow purposes by means
of lateral channels. When the flow passes through these lateral
channels, this results in a comparatively high pressure loss, on
the one hand as a result of the direction of the fluid being
changed from the lateral channel into the channels which are
enclosed by the plate pairs, but in particular because the lateral
channels normally have sharp end edges between the plate pairs
which lead to severe vortexing of the fluid, and thus to high
pressure losses. A first fluid, preferably a liquid coolant,
therefore flows through the plate pairs, with this first fluid
being less critical in terms of the pressure losses in the cooler.
At the end, a second fluid, in particular a hot medium to be
cooled, flows into and through the pack of the plate pairs, thus
resulting in the flow passing in a relatively straight line through
the plate pack, that is to say without any significant direction
changes. This results in little pressure loss for the second,
preferably gaseous, fluid. Turbulence-generating devices are
provided between the plates as appropriate for the heat-transfer
conditions. The heat exchanger according to the invention is
preferably soldered, welded, adhesively bonded etc. in one process.
Those parts which are to be soldered, welded or adhesively bonded
are in this case arranged flexibly with respect to one another,
that is to say such that they can move with respect to one another,
and can therefore in particular move relative to one another when
the soldered layers are melted during the soldering process, thus
resulting in minimal solder gaps and good soldering. The plate
pairs can advantageously be prefolded in a method step which
precedes the joining process, in particular the soldering process,
welding process, adhesive-bonding process etc., and/or can be
crimped, that is to say the plate pair comprising two plates and if
appropriate including any turbulence inserts to be provided can be
prefabricated in such a way that the plate pair is fixed by means
of lugs which are formed from one plate and surround the rim of the
other plate, so that the two plate sheets of the plate pair can no
longer slide with respect to one another, can no longer be moved
with respect to one another, or can no longer gape open during the
actual soldering process, thus ensuring that the plate pair is
soldered such that they are sealed. Crimped plates can prevent, for
example, relative movements between the housing and the plate pair
resting on it along it as a result of the components being heated
at different rates and the solder layers melting leading to
inadequate soldering of the plate pair. This also simplifies
tolerance matching between the longitudinal face of the plate pair
and the housing since, essentially, all that is necessary is to
ensure that the crimped plate pair rest on the housing during the
soldering process, without any need to consider possible movements
of the two plates with respect to one another. This ensures that
the integral connection of the flow channels and plate pairs
results in thermal conduction between the first flow, the cooling
medium, and the housing walls. Because of the thermal coupling, the
housing wall also contributes to the heat transfer, and the linking
of the plate pairs makes it possible to considerably increase the
heat-transfer area for the second fluid, depending on the
heat-exchanger geometry and the configuration of the turbulence
generators: from about 2% to more than 10% when one turbulence
sheet is provided in the channel for the second fluid, and even up
to more than 25% when turbulence generators (for example a vortex
body that is stamped into the plate) are used in the channel of the
second fluid. This results in an increase in the heat-exchanger
performance, which may be considerable. Furthermore, when using a
hot medium to be cooled, the housing wall can be adequately cooled
and can be kept at a relatively low temperature level. However,
particularly in the case of exhaust-gas coolers and boost-air
coolers, adequate cooling of the housing is often absolutely
essential in many other heat-exchanger applications since,
otherwise, very large thermal stresses will occur at the connecting
points between the housing and the plate pairs, caused by the large
temperature differences and the correspondingly different thermal
expansions of the housing carrying exhaust gas, and the cooled
plate pairs. A further major advantage of linking the longitudinal
faces of the plate pairs to the housing is the considerable
increase in the pressure resistance of the heat exchanger with
respect to the second fluid, since the plates represent a tie rod
between the two housing sides, opposing the internal pressure. The
proposed heat-exchanger concept is therefore particularly suitable
for media in which the pressure-loss requirements for the second
fluid are highly restrictive, the second fluid is very hot, or the
pressures of the second fluid are high, or combinations of these
requirements.
[0008] In one development of the invention, the flow channels are
integrally connected to the housing essentially over the entire
length of the longitudinal faces. The integral connection is
produced in particular by soldering, welding, adhesive bonding
etc., but in principle it is also possible to use any other type of
connection, such as an interlocking connection or a combination of
an integral connection and an interlocking connection.
[0009] In one development of the invention, the flow channels are
in the form of plate pairs. The plate pairs form channels for a
second fluid to pass through. There is a connection between the
plate pairs and the housing, so that the second fluid has access to
the housing and to the housing wall, and therefore, for example,
cools or heats the housing wall and the housing.
[0010] In one development of the invention the flow channels and/or
the channels for the second fluid to pass through are essentially
held in their entirety by the housing, so that the heat transfer
between the first and the second fluid takes place essentially
entirely in the interior of a housing which can be closed by a
cover, with heat likewise being transferred between the second
fluid and the housing and/or the cover, as well as between the
first fluid and the housing and/or the housing cover.
[0011] In one development of the invention, at least one flow
channel for a fluid, in particular the first fluid, is formed
between the cover of an adjacent plate, in particular a lower
plate, thus saving an upper plate, with the cover being
additionally cooled at the same time. Since the cover is integrally
connected to the housing, for example by soldering, welding,
adhesive bonding etc., and/or is connected by means of an interlock
such as forming, heat is transferred between the cover and the
housing, and vice versa, so that the housing is also cooled.
[0012] In another development of the invention, at least one flow
channel for the first fluid is formed between the base section of
the housing or the housing shell and an adjacent plate, in
particular the upper plate, and between the base section of the
housing shell, in this way likewise saving one plate, in particular
a lower plate. In particular, the first fluid then cools the
housing and the housing shell. Furthermore, however, it is also
possible to connect the upper plate to a lower plate, in particular
integrally, thus forming a plate pair which is integrally
connected, in particular by soldering, welding, adhesive bonding
etc., via at least one plate to the housing shell in the base area,
in particular to the lower plate adjacent to the base area.
[0013] In one development of the invention, the lower plate and
upper plate which in each case form a plate pair are connected to
one another by means of a fold that is formed at the rim, with the
plates therefore being connected to one another in an interlocking
manner, in particular by bending. In this case, at least one plate,
in particular the lower plate, clasps the other plate, in
particular the upper plate, thus resulting in the plates being
hooked to one another with tolerance compensation at the same time
being possible in the stacking direction of the plates and of the
plate pairs, so that, during the joining process, for example
soldering, welding, adhesive bonding etc., by means of which the
integral connection is produced, it is possible to compensate for
any openings or gaps between the plates, so that the joining
process can be carried out successfully by means of a reliable
process, thus resulting in a complete, integral connection between
the plates, in particular the upper plate and the lower plate, as
well as between adjacent plate pairs and between adjacent upper
plates and lower plates.
[0014] In one development of the invention, an inlet flow channel
and/or at least one outlet flow channel run/runs transversely
through the plate pairs, and in this case the inlet flow channel
and/or the outlet flow channel may run through the plate pairs, at
an angle of 0.degree. to 360.degree., or -360.degree., to the
stacking direction of the plates and/or to the longitudinal
direction of the plates, in particular at an angle of -50.degree.
to +500 to the stacking direction, and particularly advantageously
at an angle of 0.degree. to the stacking direction, that is to say
the inlet flow channel and/or the outlet flow channel run
essentially parallel to the stacking direction. The angles of the
outlet flow channel and of the inlet flow channel to the stacking
direction and/or to the longitudinal direction may in this case
differ, and may assume values between 0.degree. and 360.degree. or
-360.degree..
[0015] In one development of the invention, the plate pairs have at
least one depression or at least one protrusion. The depression or
the protrusion is in this case incorporated in at least one plate
of a plate pair in each case, preferably by forming techniques such
as bending, stamping, etc., or by primary forming, etc.
[0016] In one development of the invention, the protrusion or the
depression on or in a plate pair extends to an adjacent plate pair,
with the plates and the plate pairs touching, and in particular
being integrally connected to one another by soldering, welding,
adhesive bonding etc. Furthermore, an interlocking connection
and/or a combination of an interlocking connection and an integral
connection are also possible, in the same way as other
connections.
[0017] In one development of the invention, the protrusion or the
depression is incorporated in the upper plate, in particular by
forming or primary forming, in the same way as an upper plate
annular surface which touches a lower plate annular surface, which
is incorporated by forming or primary forming, of the lower plate
of an adjacent plate pair and, in particular, is integrally
connected to the lower plate annular surface by soldering, welding,
adhesive bonding, etc. and/or by means of an interlock, such as
hooking.
[0018] In another development of the invention, another protrusion
is incorporated in the lower plate, in particular by forming and/or
primary forming, in the same way as a lower plate annular surface
which touches an upper plate annular surface of the upper plate of
an adjacent plate pair and in particular is integrally connected to
the upper plate annular surface by soldering, welding, adhesive
bonding etc., and/or by an interlock, for example by hooking.
[0019] In one development of the invention, the flow channels are
stacked. The channels for the second fluid to pass through can
likewise also be stacked. In one development, the plates are
stacked such that one plate is stacked on another adjacent plate
and such that, in particular, an upper plate is placed on a lower
plate and the upper plate has a further lower plate placed on it,
on which, in turn, a further upper plate is placed, so that
adjacent plate pairs are stacked one on top of the other. The stack
formed by the plates, or the stack of plate pairs, is itself
inserted into the housing shell, which is closed by a cover. The
cover is in this case placed on the housing such that it is placed
on the housing in a stacking direction and is connected to it by an
interlock, in particular by soldering, welding, adhesive bonding
etc., and/or integrally, in particular by forming, hooking, etc.,
thus allowing tolerances to be compensated for in the stacking
direction of the flow channels and of the channels for the second
fluid to pass through, during the joining process, in particular
the soldering, welding or adhesive bonding.
[0020] In one development of the invention, the plates in a plate
pair have plate rim surfaces such that the upper plate of a plate
pair has an upper plate rim surface, and the adjacent lower plate
has a lower plate rim surface, with the upper plate rim surface
corresponding to the lower plate rim surface and being integrally
connected in particular by soldering, welding, adhesive bonding
etc. The upper plate rim surface runs in the longitudinal direction
of the plate essentially parallel to the lower plate rim surface,
and the upper plate rim surface likewise runs in the same way in
the direction of the plate width which, in particular, is formed
essentially at right angles to the longitudinal direction of the
plate and essentially at right angles to the stacking direction of
the plates, as well as essentially parallel to the lower plate rim
surface. An abutment between the lower plate rim surface and the
upper plate rim surface is formed in those sections of the upper
plate rim surface and of the lower plate rim surface in which the
longitudinal face of the plate merges into the plate width in the
stacking direction, such that the abutment of a plate rim surface
in the longitudinal direction is essentially in the form of a
quarter cylinder, and such that the quarter cylinders of the lower
plate and upper plate essentially touch like two concentric quarter
cylinders that are pushed one inside the other, and are integrally
connected, in particular by soldering, welding, adhesive bonding
etc.
[0021] In one development of the invention, the longitudinal faces
of two plate pairs which form a flow channel clasp one another at
least in places, in particular over the entire plate length, such
that the longitudinal face which touches the housing clasps the
longitudinal face of an adjacent plate, in particular the other
plate of the respective plate pair, and such that the two plates
are in this way crimped to one another.
[0022] In one development of the invention, broader faces of two
plate pairs which form a flow channel clasp one another at least in
places, in particular over the entire plate width. In this way, the
two plates, in particular the upper plate and the lower plate of a
plate pair, are crimped to one another.
[0023] In one development of the invention, the plate pairs have
turbulence-generating devices, in particular turbulence inserts or
stamped-in structure elements. In this case, the turbulence inserts
may be designed such that they are sheets with stamped-out areas
and/or meshes composed of wire. The content of the unpublished
DE102004037391.4, DE19718064B4 and DE19709601C2 is hereby expressly
disclosed.
[0024] In one development of the invention, the protrusions are
conical and are in the form of truncated cones which are produced
from a plate, preferably by forming techniques such as stamping or
primary forming. That side surface of the truncated cone which has
the smaller of the two diameters is in the form of an annular
surface, which touches the adjacent plate, preferably the lower
plate of the next plate pair, and in particular is integrally
connected to it by soldering, welding, adhesive bonding etc.
[0025] In one development of the invention, the protrusions are
streamlined, in particular with an elongated, elliptical or round
cross section.
[0026] In one development of the invention, turbulence-generating
devices are incorporated between flow channels and/or in the
channels for the second fluid to pass through. The contents of the
unpublished DE102004037391.4, DE19718064B4 and DE19709601C2 are
expressly disclosed in this context.
[0027] In one development of the invention, the folded connections
are connected to the housing, in particular to the inner surface of
the housing, with the connection being produced in particular
integrally by soldering, welding, adhesive bonding etc.
[0028] In one development of the invention, the inlet area of the
housing is arranged in front of the plate pairs in the flow
direction of the second fluid.
[0029] In one development of the invention, the outlet area of the
housing is arranged behind the plate pairs in the flow direction of
the second fluid.
[0030] In one development of the invention, the second fluid can
flow around the plate pairs essentially parallel to their
longitudinal faces.
[0031] In one development of the invention, the fold on the
longitudinal face is formed by rims of an upper plate and lower
plate in the same sense that are bent. The fold on the longitudinal
face furthermore forms a contact surface for the housing.
[0032] In one development of the invention, the fold on the
longitudinal face is formed by rims of an upper plate and lower
plate in opposite senses that are bent. The fold on the
longitudinal face furthermore forms a contact surface for the
housing.
[0033] In one development of the invention, the plate pairs have
side channels for the first fluid on the longitudinal face in the
area of the housing walls.
[0034] In this case, the side channels are in the form of an
extension of the flow cross section of the plate pairs. The
extension has a channel height which corresponds essentially to the
distance between the plate pairs.
[0035] In one development of the invention, the plate pairs have a
flow cross section with a channel width b, and the housing walls
are separated by a distance w, where b<w and material bridges
are arranged between the flow cross sections and the housing wall,
and are in particular formed from a lower plate and/or an upper
plate.
[0036] In one development of the invention, the housing is formed
in at least two parts, and has a housing shell as well as a
cover.
[0037] In one development of the invention, the inlet area of the
housing has an inlet connecting stub which is arranged in the
housing shell or in the cover. Moreover the outlet area of the
housing has an outlet connecting stub which is arranged in the
housing shell or in the cover.
[0038] In one development of the invention, the housing has an
inlet connecting stub and an outlet connecting stub for the first
fluid, with the inlet and outlet connecting stubs for the first
fluid being arranged in the cover or in the housing shell, and
having longitudinal axes which are at an angle to the plate
pairs.
[0039] In one development of the invention, the heater exchanger
has a bypass. A bypass channel for the second fluid is arranged
within the housing and parallel to the plate pairs. The mass flow
of the second fluid is for this purpose split into at least two
mass flow elements, in particular by means of a separating wall,
with at least one first mass flow element of the second fluid
flowing through the channels for the second fluid to pass through,
and with at least one second mass flow element of the second fluid
flowing through the bypass.
[0040] In one development of the invention, the plate pairs form a
pack through which the second fluid flows on two paths. A
separating wall is arranged in the inlet area for the second fluid
and/or in the outlet area for the second fluid. In this case, in
particular, the separating wall is arranged such that it can
rotate, so as to make it possible to set an angle of between
0.degree. and 360.degree. between the flow direction of the second
fluid and a longitudinal face of the separating wall.
[0041] In one development of the invention, the heat exchanger
contains at least one non-return valve, which is preferably
integrated in the housing and is located in the outlet area.
[0042] In one development of the invention, the bypass channel is
arranged above or below the plate pairs in the heat exchanger.
[0043] In one development of the invention, the bypass channel is
in the form of a bypass tube which can be inserted into the
housing. The bypass tube is in this case thermally insulated from
the flow channels (3) and/or from the channels for the second fluid
to pass through, in particular in such a way that as little heat as
possible is transferred between the second mass flow element, which
flows through the bypass channel and/or the bypass tube, and the
first mass flow element which, in particular, is cooled.
[0044] In one development of the invention, the bypass tube is
essentially arranged at a distance from the flow channels and/or
from the channels for the second fluid to pass through. The
separation is preferably provided by protrusions or stamped-out
areas which are incorporated in the bypass tube and/or in the flow
channels and/or the channels for the second fluid to pass
through.
[0045] In one development of the invention, the bypass tube
comprises at least one partial element which is preferably in the
form of an open profile and particularly advantageously is in the
form of a U-profile or half-tube.
[0046] In one development of the invention, the bypass tube
comprises two tube halves, which are preferably integrally
connected to one another by soldering, welding, adhesive bonding,
etc.
[0047] In one development of the invention, the bypass tube has at
least one longitudinal separating wall.
[0048] In one development of the invention, at least one bypass
flap is integrated in the inlet or outlet area of the housing. The
bypass flap is variable and may assume an angle from 0.degree. to
360.degree., thus splitting the mass flow of the second fluid into
the first mass flow element and the second mass flow element. The
first mass flow element flows through the channels for the second
fluid to pass through and, in particular, is cooled in the process.
The second mass flow element flows, in particular without being
cooled, through the bypass. The bypass valve can be used to adjust
and/or to provide open-loop and/or closed-loop control for the
first mass flow element of the second fluid through the channels
for the second fluid to pass through. The second mass flow element
of the second fluid through the bypass is a function of the set
first mass flow element, and can therefore likewise be subjected to
open-loop and/or closed-loop control.
[0049] In one development of the heat exchanger, the inlet area has
two separate inlet connecting stubs as well as one separating
wall.
[0050] In one development of the invention, the plate pairs form a
pack through which the second fluid flows on two paths. An inlet
chamber and an outlet chamber are arranged on one side of the plate
pack. A deflection chamber for the second fluid is arranged on the
other side of the plate pack.
[0051] In one development of the invention, the bypass is
integrated in the housing. In particular, the bypass is formed
integrally with the housing.
[0052] In one development of the invention, the bypass is
integrated in the cover. In particular, the bypass is formed
integrally with the cover.
[0053] A heat exchanger as claimed in one of the preceding claims,
characterized in that the flap is arranged in the inlet area or in
the outlet area.
[0054] In one development of the invention, the heat exchanger has
at least one bypass valve which provides open-loop and/or
closed-loop control for the volume flow and/or mass flow in
particular of the second fluid through the bypass. The bypass valve
is preferably integrated in the housing and, in particular, is
formed integrally with it. The bypass valve is arranged in the
inlet area and/or in the outlet area.
[0055] In one development of the invention, the bypass valve is a
combination valve, which is referred to in the following text as a
heat-exchanger valve device. The heat-exchanger valve device is
characterized in that the valve plate can be rotated between a
first open position, in which the bypass output is closed and the
heat-exchanger output is open, and a second open position, in which
the bypass output is open and the heat-exchanger output is closed.
The rotating valve plate makes it possible to ensure adequate
sealing, even at high pressures.
[0056] A further preferred exemplary embodiment of the
heat-exchanger valve device is characterized in that the rotating
valve plate has an opening through which fluid can pass, which, by
at least partial rotation, can be made to coincide with one of two
further openings through which fluid can pass, and which are
provided in a valve plate which is fixed relative to the valve
housing. The three openings through which fluid can pass are
preferably designed to be coincident with one another.
[0057] A further preferred exemplary embodiment of the
heat-exchanger valve device is characterized in that one of the
openings through which fluid can pass in the fixed valve plate is
connected to the heat-exchanger output, and the other opening
through which fluid can pass is connected to the bypass output.
Depending on the extent to which the openings through which fluid
can pass in the valve plates cover one another, more or less or
even no fluid is passed to the bypass output and/or to the
heat-exchanger output.
[0058] A further preferred exemplary embodiment of the
heat-exchanger valve device is characterized in that the fixed
valve plate has a depression in which the rotating valve plate is
guided. This results in the advantage that there is no need for the
valve plate to be guided on the valve housing.
[0059] A further preferred exemplary embodiment of the
heat-exchanger valve device is characterized in that the fixed
valve plate has an external thread by means of which the fixed
valve plate can be screwed into a complementary internal thread in
the valve housing. This makes it easier to fit the fixed valve
plate.
[0060] A further preferred exemplary embodiment of the
heat-exchanger valve device is characterized in that an actuator
rod projects from the rotating valve plate. The actuator rod, which
is preferably passed out of the valve housing, makes it easy to
operate the rotating valve plate.
[0061] A further preferred exemplary embodiment of the
heat-exchanger valve device is characterized in that the valve
plates are at least partially formed from ceramic. Stainless steel
can also be used instead of ceramic.
[0062] One preferred exemplary embodiment of the heat-exchanger
valve device is characterized in that the valve slide can be moved
backwards and forwards between a first extreme position, in which
the bypass output is closed and the heat-exchanger output is open,
and a second extreme position, in which the bypass output is open
and the heat-exchanger output is closed. The valve slide makes it
possible to ensure adequate sealing even at high pressures.
[0063] A further preferred exemplary embodiment of the
heat-exchanger valve device is characterized in that the valve
slide is formed partially from ceramic. Stainless steel can also be
used instead of ceramic.
[0064] A further preferred exemplary embodiment of the
heat-exchanger valve device is characterized in that the valve
housing is formed partially from ceramic. The contact surface for
the valve slide is preferably formed from ceramic.
[0065] A further preferred exemplary embodiment of the
heat-exchanger valve device is characterized in that the valve
slide is equipped with a sealing element for the input. The input
is preferably equipped with a sealing seat for the sealing
element.
[0066] A further preferred exemplary embodiment of the
heat-exchanger valve device is characterized in that the sealing
element has a sealing surface facing the input, in the form of a
spherical section. The use of a spherical section with a large
diameter makes it easier for the valve slide to move.
[0067] A further preferred exemplary embodiment of the
heat-exchanger valve device is characterized in that the sealing
element is guided such that it can move backwards and forwards on
the valve slide. This makes it easier to close the input by means
of the sealing element, which is also referred to as a closing
element.
[0068] A further preferred exemplary embodiment of the
heat-exchanger valve device is characterized in that the sealing
element is prestressed against the input by a spring device. This
allows the input to be closed to form a seal.
[0069] A further preferred exemplary embodiment of the
heat-exchanger valve device is characterized in that the valve
slide has a pressure equalizing channel. This makes it easier to
move the valve slide in the valve housing.
[0070] In one development of the invention, the integrated bypass
has a separating wall which can pivot and by means of which the
inlet connecting stub and the outlet connecting stub can be
short-circuited.
[0071] In one development of the invention, the first fluid is a
liquid coolant, in particular the coolant from the cooling circuit
of an internal combustion engine for a motor vehicle, and the
second fluid is fed-back exhaust gas from the internal combustion
engine.
[0072] In one development of the invention, the first fluid is air,
and the second fluid is fed-back exhaust gas from an internal
combustion engine for a motor vehicle.
[0073] In one development of the invention, the plate pack is
preceded by an oxidation catalytic converter, for example as
disclosed in the unpublished DE 10 2005 014 295.8. The entire
content of the unpublished DE 10 2005 014 295.8 is hereby disclosed
expressly.
[0074] In one development of the invention, the first fluid is a
liquid coolant, in particular the coolant in the cooling circuit of
an internal combustion engine for a motor vehicle, and the second
fluid is boost air which can be supplied to the internal combustion
engine.
[0075] In one development of the invention, the first fluid is air
and the second fluid is boost air which can be supplied to an
internal combustion engine for a motor vehicle.
[0076] In one development of the invention, the heat exchanger is
used as an exhaust-gas cooler in an exhaust-gas feedback system for
an internal combustion engine for a motor vehicle or as a heater
for heating the interior of a motor vehicle, in which case the heat
transferred from the second fluid to the first fluid is used to
heat the interior of the passenger compartment of a vehicle.
[0077] In one development of the invention, the heat exchanger is
used as an oil cooler for cooling engine oil for an internal
combustion engine or gearbox oil for a motor vehicle by means of a
liquid coolant, preferably the coolant in the cooling circuit of
the internal combustion engine.
[0078] In one development of the invention, the heat exchanger is
used as a coolant condenser in the coolant circuit of a
climate-control system for motor vehicles.
[0079] In one development of the invention, the heat exchanger is
used as a coolant exhaust-gas cooler in the coolant circuit of a
climate-control system for motor vehicles.
[0080] In one development of the invention, the heat exchanger is
used as a coolant vaporizer in the coolant circuit of a
climate-control system for motor vehicles.
[0081] Further advantageous refinements of the invention are
specified in the dependent claims.
[0082] One particularly advantageous refinement of the invention is
represented by concepts in which the rims of both plates of the
plate pair are formed circumferentially and without any
interruptions such that they make flat contact with one another
everywhere (FIGS. 1, 2c, 3a, 3b, 3c). This can also be described by
the two plates being formed on the circumferential outer rim
everywhere along their contact line such that they are at an angle
of 0.degree. with respect to one another on the plane at right
angles to this contact line, with this angle being greater than
10.degree. only exceptionally. In this case, the two plates can
rest flat on one another, for example, on their contact line so
that, in the section at right angles to the contact line, the two
plates run largely parallel to one another over a certain distance.
One or both plates may also, for example, be formed to be curved
with respect to one another in the area of the contact line, so
that, in the section at right angles to the contact line, the
contact of a straight line with a circle segment or, if both are
designed to be curved, the point contact of two circle segments
results, with just one contact point but no contact line.
Furthermore, for example, the rims of the two plates can also be
designed such that one has a concave shape and the other has a
convex shape, with two circle segments on the plane at right angles
to the contact line, which circle segments touch either only as a
point or points or over a certain circle-arc segment. All of these
examples have an angle of exactly 0.degree. with respect to one
another on the circumferential contact line. According to the
invention, the embodiment of the plate pairs which is described as
being straight may therefore be deigned to be very flexible,
because the housing results in the flow channel for the second
fluid being sealed everywhere on the longitudinal faces so that no
soldering to adjacent plate rims is required at the outer rims of
the plate pair. FIG. 2c represents a good compromise between
process-optimized design of the plate pair, allowing
circumferential flat contact with a small contact angle between the
two plates, and excellent thermal connection of the housing to the
channel for the first fluid.
[0083] According to a further advantageous refinement of the
invention, the housing is formed in at least two parts, that is to
say for example from a first housing part in the form of a trough,
a housing shell, and a second part in the form of a cover. The two
parts can be placed one inside the other and can easily be joined
to one another, in particular by soldering, welding, adhesive
bonding etc. A housing concept such as this also results in an
optimum joining process, in particular a soldering process, welding
process, adhesive-bonding process, etc., between the stacked plate
pairs, when the housing parts are likewise pushed one inside the
other, or placed one on top of the other, in the stacking direction
of the plate pairs, and are joined to the housing by soldering,
welding, adhesive bonding etc. during the joining process, in
particular the soldering process, welding process, adhesive-bonding
process etc. In one suitable embodiment, the housing parts can then
also move towards one another to the same extent with the plate
pairs so that, for example, no gaps or solder, welding and/or
adhesive bonding faults occur as a result of the melting solder
layers. Like the cover, the housing shells can advantageously be
produced as formed and/or primary-formed parts such as thermoformed
or deep-drawn parts, in which case the housing shells may also form
the inlet and outlet areas for the second fluid. Furthermore, inlet
and outlet connecting stubs both for the first and the second fluid
can be integrally formed, for example in the form of passages, on
the housing, irrespective of whether this is the housing shell or
the housing cover. The position and shape of the connecting stubs
can be chosen as required, depending on the requirements for the
heat exchanger. For example, the inlet and outlet connecting stubs
for the second fluid may be located at the same cooler end or at
opposite ends (see the explanatory notes relating to this further
below), and the inlet and outlet may be provided in any desired
direction, that is to say for example in the longitudinal direction
of the cooler, upwards--in this case out of the cover, downwards
from the housing or at the side out of the housing.
[0084] According to a further advantageous refinement of the
invention, a bypass channel can be arranged parallel to the plate
pack in the housing, in which case, for example, the bypass may be
in the form of a tube which is inserted into the housing and is
soldered to the other parts. A bypass such as this is particularly
advantageous when using the heat exchanger as an exhaust-gas cooler
in an exhaust-gas feedback system. Bypass arrangements such as
these in conjunction with appropriate bypass flaps for control of
the exhaust-gas flow through the heat exchanger or through the
bypass are known per 5e from the prior art. The design of the heat
exchanger according to the invention allows a bypass channel and a
bypass flap to be integrated in the exhaust-gas cooler, using
simple means. The fluid flow which is carried in the bypass must
also be carried separately from the fluid flow in the inlet area,
which flows through the heat-exchanger channels. For this purpose,
a separating plate or separating element, in the simplest form a
separating plate, can be provided in the inlet area for the second
fluid, separating the inlet area into two areas, one for the bypass
fluid flow and the other for the heat-exchanger fluid flow. By way
of example, separating elements may be clamped, welded or soldered
in one housing part or between housing parts. The separated inlet
areas may either each have their own inlet openings in the housing
or may be supplied with the fluid flows through a common inlet
opening, but which is split in two by the separating element. In
the case of the common inlet opening, of course, the two fluid
flows must also be separated in the supply line of the second
fluid, or a bypass flap must be fitted directly to the inlet
opening in a manner such that it is directly closed by the
separating element and no unacceptable leakages can occur from the
bypass side to the heat-exchanger side, and vice versa. For
example, this can be achieved by flange connection or a
flange-connected module comprising a flap, housing and actuator.
Furthermore, the bypass flap can also be integrated in the inlet
area of the second fluid such that the gas flow is passed directly
into the bypass channel or into the heat-exchanger channels, as
required. In the case of an integrated bypass flap such as this as
well, an additional separating element may also be required between
the start of the bypass and the flap for sealing purposes. All the
described solutions can likewise be provided with the same
functionality in the outlet area for the second fluid, that is to
say a separating element and bypass flap in the described
arrangements and combinations. The statements relating to the need
to separate the fluid flows in the supply line then apply in a
corresponding manner to the output line. All the solutions are also
possible with a combination valve instead of a bypass flap, that is
to say it is also possible to completely block the second fluid, in
addition to the fluid being passed into the heat-exchanger channels
or into the bypass. For example, the described bypass flaps or
valves can be operated via an electrical actuator or via a pressure
control element.
[0085] The heat exchanger according to the invention allows the
bypass channel to be embodied in widely differing ways. In one
development of the invention, the bypass is inserted underneath the
lowermost plate or above the uppermost plate in the stacking
direction of the plate pairs. It is directly adjacent to the
housing. In one development of the invention, the bypass is
inserted into the housing at the side, alongside the stacked plate
pairs. In one development of the invention, the bypass channel is
formed integrally with the housing by impressing one or more
longitudinal beads into the housing such that the bypass channel is
formed in this way and is bounded on one side by the housing wall
and on the other side by the first plate of the plate stack. In one
development of the invention, a bypass is formed such that an
essentially U-shaped shell is placed on one housing side, and in
particular is joined to it, and in particular is soldered, welded,
or adhesively bonded, etc., to it. In this case, the bypass is
enclosed between the fitted shell and the housing wall.
Furthermore, a heat exchanger according to the invention can also
be combined with a completely external bypass, that is to say a
closed flow channel for the second fluid, which can be connected to
the heat exchanger, for example by welding or soldering, or can be
fixed with the heat exchanger in common holders. However, an
external bypass may also be routed completely separately from the
heat exchanger.
[0086] In one development of the invention, any form of spacer may
be used between the plate stack and the housing wall, such as a
corrugated plate or a ribbed plate. Furthermore, it is possible to
use permeable structures such as wire meshes, porous materials or
the like. A shell extending in the longitudinal direction may also
be particularly advantageous, having a U-profile and being open
towards a housing wall. It supports the plate stack by means of the
closed side.
[0087] In one development of the invention, the structures which
form the channel project in the longitudinal direction beyond the
heat-exchanger channels formed by the stacked plates into the inlet
and/or outlet area of the second fluid. This means there is no need
for a separating element between the bypass fluid flow and the
heat-exchanger fluid flow. In one development of the invention, the
integrated bypass flap is designed such that no additional
separating element is required for the bypass channel.
[0088] The bypass channel is intended to allow the second fluid to
bypass the heat-exchanger channels without any major energy
transfer from or to the first fluid, and it should therefore be
thermally decoupled as well as possible from the first fluid. The
decoupling can be achieved, for example, by a stud or bead support
for the bypass channel against the housing wall and/or against the
plate stack. The studs or beads may in this case be stamped out
both from a structure which forms the bypass channel, for example a
tube, and/or from the housing wall or the adjacent first plate in
the plate stack. Additional insulation can also be inserted between
the bypass channel and adjacent structures as an insulating element
with poor thermal conductivity (a good insulating effect). The
insulating effect is achieved by insulating materials and/or by
shaping, in particular by means of a ribbed structure.
[0089] In one development of the invention, the bypass channel has
double walls, in particular with a thicker, load-bearing outer wall
and a thinner, inner wall. The two walls are designed such that the
outer wall is subject to less thermal stresses than the inner
wall.
[0090] A further refinement of the invention provides for the flow
to pass through the heat exchanger on two or more paths, that is to
say for the second fluid to be split into flow elements which are
each passed through some of the heat-exchanger channels parallel or
in opposite directions. The same requirements for separating plates
and inlet/outlet openings may be used to separate the flow elements
as those already described in conjunction with integration of the
bypass tube.
[0091] In one development of the invention, the exhaust-gas flow
elements are each passed in one flow from two cylinder banks. The
respective pressure surges which result in the two paths can thus
be used to increase the exhaust-gas feedback rate and the fuel
efficiency, provided that a return flow into the other path is
avoided. The return flow is therefore prevented by non-return
valves which, in particular, are integrated in the exhaust-gas
cooler in the outlet area of the second fluid or are arranged in
conjunction with a separating plate in the outlet area adjacent to
the outlet opening of the cooler housing, for example by flange
connection.
[0092] In one development of the invention, multiple-path heat
exchangers are formed with a minimum of one direction change for
the second fluid. In this case, the second fluid is not split into
flow elements but is passed through some of the fluid channels from
the inlet end of the second fluid to the other end, where this
direction is changed, in particular being changed essentially
through 180.degree., then being passed again through others of the
fluid channels. In this case, the direction may be changed in a
plurality of step elements. However, it is also possible to provide
a plurality of direction changes, with the second fluid being
output at the inlet end of the heat exchanger if there are an odd
number of direction changes, or with the outlet being at the other
end of the heat exchanger if there are an even number of direction
changes.
[0093] In one development of the invention, the direction change is
in the form of a U-flow, with the inlet and the outlet for the
second fluid being located closely adjacent to one another at one
cooler end, thus allowing the heat exchanger to be integrated to
optimize the physical space.
[0094] In one development of the invention, the heat exchanger is
in the form of a boost-air intercooler between the compressor
stages of a turbine engine, in particular with no separating
elements or other direction-changing elements being formed in the
direction-changing area, since the direction change is produced by
a housing that is closed at this end.
[0095] In one development of the invention, no separate bypass tube
is required for the U-flow embodiment since, in the bypass mode,
the connection between the inlet and outlet connecting stubs is
short-circuited in the combined inlet/output area of the cooler. In
the case of cooled exhaust-gas feedback, the path between the inlet
and outlet connecting stubs is blocked, and the second fluid, in
particular the exhaust gas, is passed through the heat-exchanger
channels.
[0096] In one development of the invention of the heat exchanger
with a U-flow, the design has an internal bypass flap and/or a
combination valve and/or an external bypass flap and/or a
combination valve. When using an external bypass flap in
conjunction with a U-flow cooler, the inlet/output area must be
split by means of a separating element, and the bypass flap is then
integrated in particular in a module which can directly
short-circuit the path through the exhaust-gas cooler.
[0097] As mentioned, the heat exchanger according to the invention
can be used particularly advantageously as an exhaust-gas cooler;
in this case, in particular, it is advantageous to cool the housing
casing, because the coolant makes direct contact with the housing
wall in places and is indirectly connected to the housing wall via
material bridges. Depending on whether it is being used for
high-pressure or low-pressure exhaust-gas feedback (exhaust-gas
extraction before or after the exhaust-gas turbine), the
exhaust-gas cooler can be cooled by the coolant in the cooling
circuit of the internal combustion engine or by air, in which case
the flow cross sections and the heat transfer are matched, for
example by means of turbulence inserts. When used as an exhaust-gas
cooler, it is also advantageous to arrange an oxidation catalytic
converter in the flow direction of the exhaust gas upstream of the
plate pairs, that is to say in the inlet area of the exhaust-gas
cooler. It is particularly worthwhile integrating an oxidation
catalytic converter upstream of the heat-exchanger tubes and any
bypass flap which may be required in the outlet area of the cooler,
since the flap/combination valve is then protected against
dirt.
[0098] The heat exchanger according to the invention can also
advantageously be used as a boost-air cooler, either with direct
cooling (air) or with indirect cooling (liquid coolant).
Furthermore, the heat exchanger according to the invention can
advantageously be used as a coolant-cooled oil cooler or as an
air-cooled condenser for a motor vehicle climate-control system.
All that is necessary for the various applications is matching to
the various media and heat-transfer relationships.
[0099] Furthermore, in addition to the two simple types of
connection comprising flow in the same direction between the first
and the second fluid or flow in the opposite direction between the
first and the second fluid (with the U-flow cooler representing a
combination of the two), it is also possible to provide more than
one circuit for the first fluid, that is to say for the first
medium. For example, in an exhaust-gas cooler application, the
coolant flow may be carried parallel to the exhaust gas in the
inlet area of the exhaust gas, thus achieving effective boiling
prevention, and the coolant flow can be carried in the opposite
direction to the exhaust gas in the outlet area of the exhaust gas,
thus achieving particularly efficient heat transfer in the rear
part of the heat exchanger, see DE10328746, whose content is hereby
expressly disclosed. The first fluid can be tapped off in the
center of the heat exchanger through a common outlet for the two
circuits, or through separate outlets. However, in order to improve
the heat transfer, it is also possible, for example, to arrange two
circuits one behind the other for the first medium, with the flow
passing through both of them in the opposite direction to the
second fluid. In this case, both circuits for the first medium have
their own inlet and outlet.
[0100] Concepts with two circuits for the first fluid flowing in
the opposite direction to the second fluid are particularly
worthwhile when the first and second media have similar thermal
capacities, or the second medium has a higher thermal capacity than
the first, and in particular also when both media are gaseous.
[0101] Exemplary embodiments of the invention will be explained in
more detail in the following text, and are illustrated in the
drawing, in which:
[0102] FIG. 1 shows a section through an exhaust-gas cooler
according to the invention with coolant channels in the form of
plates,
[0103] FIGS. 2a, 2b, 2c show further exemplary embodiments of the
design of the coolant channels with direct cooling of the housing
wall,
[0104] FIGS. 3a, 3b, 3c show further exemplary embodiments of the
design of the coolant channels with indirect cooling of the housing
walls,
[0105] FIG. 4 shows an exploded illustration of the exhaust-gas
cooler with housing shell, plate pairs and a cover,
[0106] FIG. 5a shows an exploded illustration of the plate pairs
and of the cover,
[0107] FIG. 5b shows an exploded illustration of an unjoined plate
pair which comprises at least one upper plate and at least one
lower plate, and a further lower plate of an adjacent plate
pair,
[0108] FIG. 5c shows a section C-C through an exploded illustration
of an unjoined plate pair, which comprises at least one upper plate
and at least one lower plate,
[0109] FIG. 5d shows a perspective illustration of a joined plate
pair,
[0110] FIG. 5e shows a view of a joined plate pair in the flow
direction of the second fluid,
[0111] FIGS. 6a, 6b, 6c show embodiments of a two-part housing for
the exhaust-gas cooler,
[0112] FIGS. 7a, 7b show longitudinal sections through the
exhaust-gas cooler with different exhaust-gas and coolant
routing,
[0113] FIGS. 8a, 8b show longitudinal sections through the
exhaust-gas cooler with an integrated bypass tube and separating
wall in the inlet or outlet area,
[0114] FIG. 9 shows a longitudinal section through an exhaust-gas
cooler with a bypass tube and an integrated bypass flap,
[0115] FIG. 10 shows a longitudinal section through an exhaust-gas
cooler with a bypass tube and two separate inlet connecting
stubs,
[0116] FIG. 11 shows a longitudinal section through an exhaust-gas
cooler with an exhaust-gas flow direction change (two-path
through-flow),
[0117] FIG. 12 shows a longitudinal section through an exhaust-gas
cooler with a two-path flow through it and with an integrated
bypass with a bypass flap,
[0118] FIG. 13 shows a longitudinal section through an exhaust-gas
cooler with an oxidation catalytic converter in the exhaust-gas
inlet area,
[0119] FIG. 14 shows a longitudinal section through an exhaust-gas
cooler with two paths and in each case one non-return valve for
each path in the outlet area of the second fluid,
[0120] FIG. 15 shows a longitudinal section D-D through two crimped
and joined plate pairs, and
[0121] FIG. 16 shows a longitudinal section through an exhaust-gas
cooler with a change in the direction of the exhaust-gas flow
(two-path flow through it), with the fluid in one path entering the
exhaust-gas cooler, and emerging from the exhaust-gas cooler
through the other path.
[0122] FIG. 1 shows a heat exchanger 1 according to the invention
which is in the form of an exhaust-gas cooler and can be used in an
exhaust-gas feedback system for an internal combustion engine for
motor vehicles. Exhaust-gas feedback systems are known from the
prior art: in this case, the exhaust gas from the internal
combustion engine is tapped off upstream or downstream of an
exhaust-gas turbine (high-pressure or low-pressure feedback), and
is supplied again to the induction manifold of the internal
combustion engine having been cooled in one or two stages. The
amount of exhaust gas tapped off is controlled by an exhaust-gas
feedback valve. Exhaust gas flows through the illustrated
exhaust-gas cooler 1 and is cooled by a liquid coolant which is
preferably taken from the cooling circuit of the internal
combustion engine. The exhaust-gas cooler 1 has a two-part housing
2 which comprises a housing shell 2a in the form of a trough and a
cover 2b--in which case both parts are preferably in the form of
sheet-metal parts and can be produced by thermoforming or
deep-drawing. A pack of plate pairs 3 is arranged in the housing
shell 2a, and the coolant flows through it. The plate pairs 3
extend over the entire width of the housing shell 2a, which has two
housing walls 2c and 2d, which are illustrated at right angles in
the drawing, and run parallel to one another. The plate pairs 3
have longitudinal faces 3a which rest on the housing walls 2c, 2d,
and form flow channels which are fitted with turbulence inserts 4
in order to increase the heat transfer. The plate pairs 3 are
arranged parallel and at a distance from one another, and form
channels 5 for the exhaust gas to pass through. Turbulence inserts
6 are arranged in the channels 5 for the exhaust gas to pass
through, in order to increase the heat transfer. All of the parts
of the exhaust-gas cooler 1 are integrally connected to one
another, that is to say by means by soldering. The soldering is
preferably carried out in one process in a solder oven that is not
illustrated. The plate pairs each have an upper plate 80b and a
lower plate 80c.
[0123] FIG. 2a shows a further exemplary embodiment of the
invention in the form of a detail comprising an exhaust-gas cooler,
with the same reference numbers as in FIG. 1 being used for the
same parts. Two plate pairs 7 are arranged between the two housing
walls 2c, 2d, facing away from one another and connected by their
longitudinal faces 7a to the housing walls 2c, 2d, by soldering.
The plate pairs 7 each comprise an upper plate 7b and a lower plate
7c, which are connected to one another by a fold at the rim. The
flow cross section through which the coolant flows extends to the
housing walls 2c, 2d and thus provides cooling for the housing
walls which are heated by the exhaust-gas flow.
[0124] FIG. 2b shows a further exemplary embodiment of the
invention relating to the design of a plate pair 8 which is
composed of an upper plate 8a, 80b and a lower plate 8b, 80c and is
closed at the side by a respective fold 8c. The flow cross section
of the plate pair 8 is extended at the side to form side channels
8d, 8e which are approximately the same height as the exhaust-gas
channels 5 and the turbulence inserts 6 which are arranged in the
exhaust-gas channels 5. The side channels 8d, 8e through which the
coolant flows therefore extend from one plate pair 8 to the
adjacent plate pair, and rest over their entire area on the housing
walls 2c, 2d. This results in very good cooling of the housing
walls 2c, 2d, which are therefore insulated from the exhaust-gas
flow. The same features are provided with the same reference
symbols as in the previous figures.
[0125] FIG. 2c shows a further embodiment of the plate pairs 9,
comprising an upper plate 80b and a lower plate 80c, between
housing walls 2c, 2d, with an extension of the flow cross section
forming side channels 9a, 9b, although these are not as high as the
exhaust-gas channels, but are only a portion of its height, for
example 50%, with the rest of the channel height in each case being
bridged by a longitudinal fold 9c, 9d. This embodiment also results
in very good cooling of the housing walls 2c, 2d, since coolant
flows around them. The same features are provided with the same
reference symbols as in the previous figures.
[0126] FIGS. 3a, 3b, 3c show further exemplary embodiments of the
invention of embodiments of plate pairs 10, 11, 12 which are each
formed from an upper plate 80b and a lower plate 80c, whose flow
channels have a width b which is less than the unobstructed width w
of the housing--material bridges 10a, 10b, 11a, 11b, 12a, 12b which
each run in the longitudinal direction are arranged between the
flow channels of the plate pairs 10, 11, 12 and, in each case in
different embodiments, rest on the housing walls 2c, 2d and are
soldered to them. This likewise results in a good cooling effect,
that is to say the housing walls 2c, 2d are cooled indirectly, that
is to say by thermal conduction via the material bridges 10a, 10b,
11a, 11b, 12a, 12b. The same features are provided with the same
reference symbols as in the previous figures.
[0127] FIG. 4 shows a 3D illustration of the individual parts of an
exhaust-gas cooler which corresponds to the exemplary embodiment
shown in FIG. 1. The same features are provided with the same
reference symbols as in the previous figures. A housing shell 13 in
the form of a trough is shown at the bottom of the drawing, and has
an exhaust-gas inlet opening 13a at the end, that is to say on its
narrow face, and an exhaust-gas outlet opening 13b on the opposite
narrow face (the majority of which is concealed). Three plate pairs
14, a cover plate 15 and the housing cover 16 are shown above the
housing shell 13. The approximately rectangular plate pairs 14 have
angled rim strips 14a, which are in the form of folds and can be
soldered to the inside of the housing shell 13, on each of their
longitudinal faces. Coolant flows through the plate pairs 14 and
they therefore have depression-like protrusions 14b, 14c, which, in
the soldered state, respectively form an inlet channel and an
outlet channel for the plate pairs, through which flow can then
pass parallel to one another. The coolant connections (not shown
here) are located in the cover 16 of the housing. As can also be
seen from this illustration, the individual parts of the
exhaust-gas cooler can be joined and prepared for the soldering
process in a simple manner.
[0128] FIG. 5a shows a further illustration of the plate pairs 14
shown in FIG. 4, viewed from the front, that is to say seen in the
flow direction of the exhaust gas. The same reference numbers are
used as those in FIG. 4. The plate pairs 14 are arranged parallel
and at a distance from one another and form approximately
rectangular flow channels (channels for the flow to pass through)
17 for the exhaust gas, with turbulence inserts, as illustrated in
FIGS. 1 to 3, in this case having been omitted. The plate pairs 14
each comprise two plates, specifically an upper plate 14d and a
lower plate 14e, which are connected to one another on each of
their longitudinal faces by the angled fold 14a. The end faces 14f,
which form the inlet flow edges for the exhaust gas, are in
contrast connected to one another by a flat fold. The plate pairs
14 are therefore circumferentially sealed at the rim. The
depression-like protrusions 14b are formed from the upper plate 14d
and rest on the adjacent lower plate 14e-thus creating an
inlet-flow and an outlet-flow channel, which run transversely with
respect to the exhaust-gas flow direction, for the coolant. The
protrusions are streamlined in order to achieve a small pressure
drop on the exhaust-gas side, for example as is shown in FIG. 4
with an oval or elliptical cross section. Apart from this,
depending on the application, structure elements in the form of
beads or so-called winglets can also be formed in the plates,
instead of the turbulence inserts.
[0129] FIG. 5b shows an exploded illustration of an unjoined plate
pair 3, 14 which comprises at least one upper plate 80b and at
least one lower plate 80c, as well as a further lower plate 80c of
an adjacent plate pair. The same features are provided with the
same reference symbols as in the previous figures. The upper plate
80b and the lower plate 80c each have a plate opening 81, which is
in the form of a hole. The upper plate 80b has at least one
protrusion 14b, in particular two protrusions 14b, which are in the
form of truncated cones in the stacking direction. The truncated
cone has an upper plate annular surface 82, 82c on the side with
the smallest external diameter, which upper plate annular surface
82, 82c is arranged parallel to the plate surface 92 of the upper
plate 80b and of the lower plate 80c, and at right angles to the
stacking direction of the plate pairs 3, 14. The lower plate 80c
has a lower plate annular surface 83, 83c, which is formed
integrally with the plate surface 92 and is identical to it in the
area of the plate opening. In the joined state, in particular in
the soldered, welded, adhesively bonded, etc. state, the upper
plate annular surface 82, 82c of a plate pair 3, 14 and the lower
plate annular surface 83, 83c of an adjacent plate pair 3, 14
touch, and are integrally connected to one another. The upper plate
80b has an upper plate rim surface 85 at the plate rims. The lower
plate 80c has a lower plate rim surface 86 at the plate rims. The
upper plate rim surface 85 and the lower plate rim surface 86
correspond to one another and are integrally connected to one
another, in particular by soldering, welding, adhesive bonding etc.
The upper plate rim surface 85 runs in the longitudinal direction
of the plate essentially parallel to the lower plate rim surface
86, in the same way as the upper plate rim surface 85 in the
direction of the plate width, which runs essentially parallel to
the lower plate rim surface, in particular aligned essentially at
right angles to the longitudinal direction of the plate and
essentially at right angles to the stacking direction of the
plates. An abutment 93 between the lower plate rim surface and the
upper plate rim surface is formed in those sections of the upper
plate rim surface and of the lower plate rim surface in which the
longitudinal face of the plate merges into the plate width in the
stacking direction, such that the abutment 93 of one plate rim
surface is essentially in the form of a quarter cylinder in the
longitudinal direction, and such that the quarter cylinders of the
lower plate and upper plate touch essentially like two concentric
quarter cylinders which have been pushed one inside the other, and
are integrally connected to one another, in particular by
soldering, welding, adhesive bonding etc.
[0130] FIG. 5c shows a section C-C through the exploded
illustration in FIG. 5b of an unjoined plate pair, which has at
least one upper plate 80b and at least one lower plate 80c. The
same features are provided with the same reference symbols as in
the previous figures.
[0131] FIG. 5d shows a perspective illustration of a joined plate
pair 3, 14. The same features are provided with the same reference
symbols as in the previous figures. In the joined state, in
particular in the soldered, welded, adhesively bonded etc. state,
the upper plate annular surface 82, 82c of a plate pair 3, 14 and
the lower plate annular surface 83, 83c of an adjacent plate pair
3, 14 touch and are integrally connected to one another. At the
plate rims, the upper plate 80b has an upper plate rim surface 85.
The lower plate 80c has a lower plate rim surface 86 at the plate
rims. The upper plate rim surface 85 and the lower plate rim
surface 86 correspond to one another and are integrally connected
to one another, in particular by soldering, welding, adhesive
bonding etc. The upper plate rim surface 85 runs essentially
parallel to the lower plate rim surface 86 in the longitudinal
direction of the plate, in the same way as the upper plate rim
surface 85 runs in the direction of the plate width, essentially
parallel to the lower plate rim surface, and in particular is
aligned essentially at right angles to the longitudinal direction
of the plate and essentially at right angles to the stacking
direction of the plates. An abutment 93 between the lower plate rim
surface and the upper plate rim surface is formed in those sections
of the upper plate rim surface and of the lower plate rim surface
in which the longitudinal face of the plate merges into the plate
width in the stacking direction, such that the abutment 93 of the
plate rim surface is essentially in the form of a quarter cylinder
in the longitudinal direction, and in such a way that the quarter
cylinders of the lower plate and upper plate essentially touch one
another like two concentric quarter cylinders which have been
pushed one inside the other, and are integrally connected to one
another, in particular by soldering, welding, adhesive bonding
etc.
[0132] FIG. 5e shows a view of a joined plate pair in the flow
direction of the second fluid. The same features are provided with
the same reference symbols as in the previous figures.
[0133] FIGS. 6a, 6b, 6c show different forms of the embodiment of
housings 17, 18, 19, which each have housing shells 17a, 18a, 19a
in the form of boxes or troughs. The same features are provided
with the same reference symbols as in the previous figures. The
cover shapes 17b, 18b, 19b are different. The cover 17b has a
circumferential bead (groove) 17c, which can be placed on the
circumferential upper edge of the housing shell 17a, and can thus
be soldered. The cover 18b has a circumferential rim 18c which
projects upwards and rests on the inner wall of the housing shell
18a. The cover 18b can thus "sag" during soldering (during melting
of the solder layers in the plate pack). The cover 19b has an
angled rim 19c, which clasps the outside of the upper edge of the
housing shell 19a and can therefore also be soldered
circumferentially. All the illustrated parts can be produced at low
cost as deep-drawn or thermoformed parts.
[0134] FIG. 7a shows an exhaust-gas cooler 20 in the form of a
longitudinal section with a housing 21, comprising a housing shell
21a, a cover 21b, an inlet for the first fluid 90 and an outlet for
the first fluid 91. A pack 22 (illustrated by dashed lines)
comprising the already mentioned plate pairs, which are not
illustrated here but through which coolant can flow, is arranged in
the housing 21. The same features are provided with the same
reference symbols as in the previous figures. The relevant coolant
connections are arranged as connecting stubs 23, 24 in the cover
21b of the housing 21. The exhaust gas, represented by arrows A,
enters the exhaust-gas cooler 20 through an inlet connecting stub
25, and leaves it via an outlet connecting stub 26. An inlet area
27 is incorporated in the exhaust-gas flow direction upstream of
the plate pack 22 and acts as a diffuser, and an outlet area 28 is
incorporated in the housing 21 downstream from the plate pack 22,
and merges into the outlet connecting stub 26. The exhaust gas,
represented by the arrows A, therefore flows essentially in the
longitudinal direction ("axially") through the exhaust-gas cooler
20 and through the plate pack 22.
[0135] FIG. 7b shows a similar exhaust-gas cooler 29 with the
difference that the coolant connections 30, 31 are arranged in the
base part of the cooler, and the exhaust-gas connecting stop 32 on
the outlet side is arranged in the cover part of the housing, thus
making it possible to change the direction of the emerging exhaust
gas through 90.degree., represented by an arrow A. The same
features are provided with the same reference symbols as in the
previous figures. Changes such as these in the exhaust-gas and
coolant inlet and outlet are therefore possible by simple measures
on the housing. FIGS. 7a, 7b show exhaust-gas and coolant flows in
the same direction. However, it is also possible for the two media
to flow in opposite directions to one another.
[0136] FIGS. 8a and 8b show further exemplary embodiments of the
invention, to be precise an exhaust-gas cooler 33 with a bypass
channel 34 arranged at the bottom, and an exhaust-gas cooler 35
with a bypass channel 36 arranged at the top. The same features are
provided with the same reference symbols as in the previous
figures. The two bypass channels 35, 36 may be in the form of a
tube and may be introduced into the housing, in each case parallel
to the plate packs 37a, 37b, which are illustrated in shaded form.
In the exhaust-gas inlet area, the exhaust-gas cooler 33 shown in
FIG. 8a has a separating or sealing element 38, which is used to
separate the exhaust-gas flow into two flow elements for the plate
pack 37a on the one hand and the bypass tube 34 on the other hand.
The exhaust-gas cooler 35 shown in FIG. 8b has an exhaust-gas
supply with a direction change through 90.degree. from the cover
side, corresponding to which an angled separating element 39 is
arranged in the exhaust-gas inlet area, and seals the exhaust-gas
flow elements from one another. A bypass valve, which is not
illustrated, is therefore arranged outside the exhaust-gas cooler
in both cases.
[0137] FIG. 9 shows a further exemplary embodiment of the invention
in the form of an exhaust-gas cooler 40 with a plate pack 41 and a
bypass channel 42 arranged under it, with a bypass flap 43, which
can pivot, being arranged in the exhaust-gas inlet area,
represented by the exhaust-gas arrow A. The same features are
provided with the same reference symbols as in the previous
figures. The exhaust-gas flow can therefore be passed either
through the plate pack 41 or through the bypass channel 42, with
intermediate positions also being possible. The design of a bypass
flap is known from the prior art, and is also referred to as an
exhaust-gas switch.
[0138] FIG. 10 shows a further exemplary embodiment of the
invention in the form of an exhaust-gas cooler 44 with a plate pack
45 (heat-exchanger part) and a bypass channel 46 arranged at the
top, each of which have separate associated exhaust-gas inlets 47,
48 in the housing of the exhaust-gas cooler 44. The same features
are provided with the same reference symbols as in the previous
figures. A separating element or separating wall 49 is arranged
between the two exhaust-gas inlets 47, 48, and can be soldered to
the housing.
[0139] FIG. 11 shows a further exemplary embodiment of the
invention in the form of an exhaust-gas cooler 50 through which
flow passes on two paths and which has a plate pack 51
(heat-exchanger part), an exhaust-gas inlet chamber 52, an
exhaust-gas outlet chamber 53, which is separated by a separating
wall, and a deflection chamber 54 for the exhaust-gas flow,
represented by an elongated U-shaped arrow A. The same features are
provided with the same reference symbols as in the previous
figures.
[0140] FIG. 12 shows a further exemplary embodiment of the
invention, specifically an exhaust-gas cooler 55 through which the
flow passes on two paths and which has an exhaust-gas chamber 56
with an exhaust-gas inlet connecting stub 57 and an exhaust-gas
outlet connecting stub 58. The same features are provided with the
same reference symbols as in the previous figures. An exhaust-gas
flap 59 (solid line) which can pivot is arranged in the exhaust-gas
chamber 56 and can be pivoted to a position 59' represented by
dashed lines. In the position 59, the inlet connecting stub 57 and
the outlet connecting stub 58 are separated from one another, that
is to say the exhaust-gas flow flows through the heat-exchanger
part 60 corresponding to the U-shaped arrow A, and emerges through
the exhaust-gas connecting stub 58; the entire exhaust-gas flow is
therefore cooled. In the situation in which no exhaust-gas cooling
is required, the exhaust-gas flap 59 is moved to the position 59'
represented by dashed lines, so that the exhaust-gas flow entering
the inlet connecting stub 57 is passed
directly--short-circuited--into the outlet connecting stub 58, and
emerges from the exhaust-gas cooler 55. The exhaust-gas chamber 56
therefore forms a bypass channel, represented by a dashed arrow B.
The plate pack 60 can therefore be bypassed in the bypass. The
exhaust-gas cooler 55 therefore has an integrated bypass, with an
integrated bypass flap.
[0141] As a further exemplary embodiment of the invention, FIG. 13
shows an exhaust-gas cooler 61 with a heat-exchanger part 62 (plate
pack) through which exhaust gas can flow on one path ("axially"),
corresponding to the exhaust-gas arrows A. The same features are
provided with the same reference symbols as in the previous
figures. The exhaust-gas cooler 61 has an exhaust-gas inlet area
63, which is in the form of a diffuser and in which an oxidation
catalytic converter 64 is arranged which, as is known from the
prior art, is used for exhaust-gas purification. In addition to the
space-saving design, this arrangement has the advantage that the
exhaust-gas channels in the oxidation catalytic converter, which
are not illustrated, allow the exhaust-gas flow to be carried in
one direction and therefore allow this flow to be passed in a
better manner to the downstream plate pack 62.
[0142] FIG. 14 shows a longitudinal section through an exhaust-gas
cooler with two paths, and in each case a non-return valve for each
path, in the outlet area of the second fluid. The same features are
provided with the same reference symbols as in the previous
figures. A first path 87 of the second fluid enters the inlet area
of the second fluid into the heat exchanger and, in particular,
this first path 87 is in the form of a bypass, as well as a second
path 88 for the second fluid. The first path 87 and the second path
88 are separated from one another, such that they are sealed, by a
sealing element 89 in the form of a separating wall. The sealing
element 89 is designed to be streamlined for the second fluid, such
that the paths which enter the heat exchanger at an angle to the
plate longitudinal direction are passed through the radiused
sealing element to the inlet to the plate pack in the plate
longitudinal direction. A first non-return valve 94 for the first
path and a second non-return valve 95 for the second path are
integrated in particular in the outlet area of the heat exchanger
and are designed such that the first non-return valve 94 has a
first rotating joint 98 adjacent to the housing base which allows a
pivoting movement of a first valve flap 96 about a rotation axis
which is arranged parallel to the plate width and at right angles
to the plate longitudinal direction. The second non-return valve 95
has a second rotating joint 99, which is arranged adjacent to the
housing cover and allows a pivoting movement of a second valve flap
97 about a rotation axis which is arranged parallel to the plate
width and at right angles to the plate longitudinal direction. This
prevents the second fluid from flowing back from the outlet area
into the plate pack.
[0143] FIG. 15 shows a longitudinal section D-D through two crimped
and joined plate pairs. The same features are provided with the
same reference symbols as in the previous figures. The upper plates
80b and the lower plates 80c are arranged essentially parallel and
at a distance from one another, with the distance between an upper
plate 80b and a lower plate 80c of a plate pair 3, 14 forming the
height of the flow channel for the first fluid, and the distance
between a lower plate 83 and the upper plate 82 of an adjacent
plate pair forming the height of the channel for the second fluid
to pass through. The lower plates 81c have an opening 81, around
which a lower plate annular surface 83 is formed, concentrically.
The upper plates 81b likewise have an opening 81. Conical
protrusions 14b are formed conically in the area of these openings,
at right angles to the plate surface and out of the upper plates in
the stacked-plate direction. The protrusion bends in the section of
the protrusion 14b with the smaller of the two cone diameters which
are located at the two cone ends, and runs parallel to the plate
surface, thus forming an upper plate annular surface 82 which
touches the lower plate annular surface 83 of an adjacent plate
pair, and is integrally connected to it, in particular by
soldering, welding, adhesive bonding, etc. The upper plates bend
beyond the protrusions 14b in the direction of the inlet area for
the second fluid in the direction of the housing base. The height
of the flow channel decreases until the upper plate 80b and the
lower plate 80c of a plate pair touch and run parallel to one
another, and are integrally connected to one another, in particular
by soldering, welding, adhesive bonding etc. The lower plate 80c
projects somewhat beyond the length of the upper plate 80b in the
longitudinal direction, thus creating an end-width area 101 of the
lower plate 80c which is bent around the associated upper plate 80b
of the plate pair 3, 14, at least in places, over the entire plate
width, and therefore clasps the upper plate, which is referred to
as crimping. The crimping also reduces the flow losses at the inlet
of the second fluid to the plate pairs in comparison to the inlet
arriving at an edge. In the same way, the lower plates are crimped
to the upper plates at least in places over the entire plate width
on the outlet side of the plate pack, although this is not
illustrated in FIG. 15. The crimping is also carried out at least
in places over the two longitudinal faces of the plates, although
this is likewise not illustrated in FIG. 15. In a further
embodiment which is not illustrated, the upper plate can also clasp
the lower plate.
[0144] FIG. 16 shows a longitudinal section through an exhaust-gas
cooler with the direction of the exhaust-gas flow being changed
(flow through it on two paths), with the fluid entering the
exhaust-gas cooler on one path, and leaving the exhaust-gas cooler
through the other path. The same features are provided with the
same reference symbols as in the previous figures. The inlet and
the outlet of the second fluid are located on one of the same sides
of the heat exchanger. They are separated from one another, with a
seal, by a sealing element 89, which is in the form of a wall. The
second fluid enters the heat exchanger through the inlet/outlet
area and its direction is changed as a U-flow, with the second
fluid flowing in the opposite direction to the outlet area, and
leaving the heat exchanger. The inlet and the outlet for the second
fluid are arranged close to one another at one cooler end, thus
allowing the heat exchanger to be integrated, in an optimum
physical space.
[0145] The turbulence-generating elements and the turbulence
inserts are in the form of web ribs in a further embodiment, which
is not illustrated.
[0146] Turbulence inserts with web ribs have comparatively less
tendency to accumulate deposits despite their flow cross sections
being fundamentally smaller than those of other inserts. In
principle, there was a concern that turbulence inserts with web
ribs would lead to increased blocking of individual channels for
the flow to pass through, owing to the fine-element structure of
the web ribs. However, this is true to a surprisingly small extent,
particularly if the webs of the web ribs are relatively short. One
possible explanation for this could be that the turbulent flow
which is created over large parts of the web-rib insert in the
exhaust gas reduces the deposition of particles while in contrast
organized flows are formed in longer, single-form channels, which
promote the deposition of particles close to walls, because the
flow speed is very low there.
Re FIGS. 1 to 16
[0147] In one preferred embodiment, the webs of the web ribs have a
length which is no more than about 10 mm, preferably no more than
about 5 mm, and particularly preferably no more than about 3 mm.
Depending on the available physical space and the internal
combustion engine, there may be specific requirements for the
pressure drop across the exhaust-gas heat exchanger. One of the
abovementioned length ranges may be preferred, depending on these
requirements.
[0148] Furthermore, the density of the web ribs transversely with
respect to the exhaust-gas flow direction is preferably between
about 20 web ribs per dm and about 50 web ribs per dm, preferably
between about 25 web ribs per dm and 45 web ribs per dm. These web
rib densities have been found to be particularly suitable in
trials. In particular, the web ribs particularly advantageously
represent a good compromise between the risk of blocking and
cooling performance.
[0149] With respect to the height of the web ribs, it should be
remembered that, if they are high, only relatively small primary
areas, that is to say surfaces cooled by coolant, are available,
via which all of the heat must be dissipated into the coolant. If
the primary areas are relatively small, the risk of a liquid
coolant burning is then increased. Furthermore, the efficiency of
the inserts decreases as the height of the web ribs increases. A
preferred height for the insert or web rib is therefore between
about 3.5 mm and about 10 mm, particularly preferably between about
4 mm and about 8 mm, and in particular preferably between about 4.5
mm and about 6 mm.
[0150] In one preferred development of the apparatus according to
the invention, it is possible for an oxidation catalytic converter
to be arranged upstream of the plurality of flow channels. In
general, a catalytic converter such as this makes it possible to
reduce the particle sizes, particle densities and the proportions
of hydrocarbons in the exhaust gas, by oxidation. In this case,
additionally or alternatively, it is possible to provide for the
inserts themselves to be provided with a coating for catalytic
oxidation of the exhaust gas. Particularly in conjunction with
oxide-catalytic means, the web rib densities that can sensibly be
used transversely with respect to the exhaust-gas flow direction
may be more than about 50 web ribs per dm, in particular about 75
web ribs per dm. This will result in particularly good
heat-exchanger performance for a given physical space without the
long-term risk of blocking as a result of deposits.
[0151] In one particularly preferred embodiment, the web ribs have
inclined teeth. Ribs with inclined teeth have been found
experimentally to be particularly suitable for ensuring good
long-term stability of the exhaust-gas heat exchanger against
deposits. In this case, in one preferred embodiment, the angle
between the web walls and a main direction of the web ribs is
between about 1.degree. and about 45.degree.. In one particularly
preferred embodiment the angle is between about 5.degree. and about
25.degree., although, in an alternative preferred embodiment, it
may also be between about 25.degree. and about 45.degree.. The
first-mentioned value range from 5.degree. to 25.degree. is
particularly highly suitable for normal applications, which are
particularly sensitive to pressure losses, with the
second-mentioned value range being suitable to achieve an optimized
power density, in particular for applications which are less
sensitive to pressure losses.
[0152] In general, a correlation can be found between the angle of
the walls and a longitudinal pitch of the web ribs for optimization
of an insert with obliquely toothed web ribs. In this case, in
particular, optimum embodiments with small angles may have greater
pitches 1 than optimized embodiments with large angles. Embodiments
with a moderate pressure loss result in particular with small
inclination angles. Embodiments with optimized power density can be
obtained in particular with large inclination angles. Particularly
in the case of small inclination angles, the longitudinal pitch may
be greater while, for large inclination angles, the longitudinal
pitch may in particular be less, in order to obtain optimized
embodiments.
[0153] In one preferred embodiment, the apparatus is in the form of
a stacked-plate heat exchanger. This embodiment is particularly
appropriate both in terms of the width of a flow channel and in
terms of cost-effective manufacture and the capability to combine a
heat-exchanger housing with web-rib inserts. Alternatively, the
apparatus may, however, also be in the form of a tube-bundle heat
exchanger, or may be some other heat-exchanger form that is known
per se.
[0154] It is generally preferable for the insert to be manufactured
from a stainless steel, in particular from an austenitic steel, in
order to prevent corrosion being caused by the corrosive exhaust
gas.
[0155] In a further advantageous refinement, aluminum materials may
be used, in which case it may then be particularly advantageous to
provide suitable corrosion protection, in particular such as an
alloy and/or a coating.
[0156] In one advantageous embodiment, the insert is formed from
aluminum. Inserts formed from aluminum have a particularly light
weight. It is particularly advantageous to form the inserts from
aluminum by means of an alloy or coating, for corrosion
protection.
[0157] Depending on the flow parameters, in particular the Reynolds
number, the length of inlet area of the flow channels, in
particular tubes and/or stacked-plate pairs, 1/s is approximately
2.5 to 5, and the length of the web ribs must be chosen to be below
this limit value. S denotes the mean cross-sectional width between
two webs, and is therefore b/2-t, where t is the metal-sheet
thickness. This results in a required ratio 1/s of less than 4, in
particular 1/s of less than 2. If there is a high risk of blocking
as a result of a critical exhaust-gas composition, 1/s should be
chosen to be less than 1.5, in particular 1/s<1.
[0158] The inclined position of the webs results in a higher flow
speed on the wall on the swirl side, counteracting particulate
deposits. A further major advantage of web ribs with inclined teeth
is that, in situations in which a low web-rib density in the
direction at right angles to the flow is necessary in order to
avoid blocking, particularly with a poor exhaust-gas composition,
adequate cooler performance can be ensured despite a small rib
surface area.
[0159] The stacked-plate heat exchanger according to the invention
has an outer housing with a cover, with an inlet and an outlet
being provided for the exhaust gas, as well as an inlet and an
outlet for a liquid coolant. A plurality of plate elements are
provided within the housing, with each of the plate elements
comprising an upper half and a lower half. The plate elements are
welded to one another and to the housing by means of collars that
are placed on them, such that the coolant in each case flows from
the inlet to the outlet between the two halves of one plate
element. An insert, which is not shown but has web ribs, is
arranged between two plate elements in each case, with the
intermediate space between two plate elements in each case forming
a flow channel for the exhaust gas. The inserts are not
illustrated, for clarity reasons. The inserts are composed of a
stainless steel. In order to improve the thermal contact between
the inserts and the plate elements and/or the housing, the inserts
may be welded or soldered flat to the said elements.
[0160] In a further embodiment, the turbulence insert is formed
from a thin sheet-metal material, in which parallel web ribs are
incorporated by forming measures. Each of the web ribs has a row of
webs arranged one after the other in the exhaust-gas flow
direction. Two webs which follow one another in the exhaust-gas
flow direction are in each case arranged offset with respect to one
another through half the web width transversely with respect to the
exhaust-gas flow direction, so that each web is followed by a sharp
edge followed by a web. In the present example, the walls are
aligned parallel to the flow direction of the exhaust gas and form
an angle of 0.degree. with an axis B of the web ribs and the main
flow direction of the exhaust gas A. A web rib insert such as this
is referred to as a straight-toothed web rib.
[0161] In the first exemplary embodiment, the length 1 of a web is
about 4 mm. The width b of a single web rib is defined as the width
of the cyclic unit of the periodic structure transversely with
respect to the main flow direction of the exhaust gas. The web rib
density 2/b in the present example is about 40 web ribs per dm. The
width b of a web rib is thus about 5 mm.
[0162] The height h of the web ribs corresponds to the distance
between two adjacent plate elements of the heat exchanger, and in
the present case is about 5 mm.
[0163] In a further refinement of the web-rib insert, the side
walls of the individual webs are in this case not aligned parallel
to the main direction B of the web ribs. In fact, each of the walls
of the webs includes an angle W of about 30.degree. with the main
direction B of the web ribs. The further dimensions of the
obliquely toothed web-rib inserts correspond to the dimensions of
the straight-toothed web rib.
[0164] Suitable longitudinal pitches 1 for corresponding angles of
the walls W in suitable embodiments are 10.degree. with
longitudinal pitches 1 of less than about 10 mm, 20.degree. with 1
less than about 6 mm, 30.degree. with 1 less than about 4 mm, and
45.degree. with 1 less than about 2 mm.
[0165] The minimum longitudinal pitch 1 is about 1 mm for all
angles. The permissible channel extent 1/s is within approximately
the same limit as that for straight-toothed web ribs, with s being
the web separation transversely with respect to the main flow
direction B. It is generally difficult to produce longitudinal
pitches 1 of less than 1 mm, for manufacturing reasons.
[0166] The at least one heat exchanger is at least one exhaust-gas
heat exchanger and/or a boost-air cooler and/or an oil cooler
and/or a coolant cooler and/or a coolant condenser for a
climate-control system and/or a gas cooler for a climate-control
system and/or a coolant vaporizer for a climate-control system
and/or a cooler for cooling electronic components.
[0167] In a first embodiment, the boost-air cooler and/or
exhaust-gas cooler is a direct boost-air cooler and/or direct
exhaust-gas cooler. In this case, direct should be understood as
meaning that at least one medium to be cooled, such as exhaust gas
and/or boost air, is cooled directly by a cooling medium such as
air.
[0168] In a second embodiment, the boost-air cooler and/or
exhaust-gas cooler is an indirect boost-air cooler and/or indirect
exhaust-gas cooler. In this case, indirectly should be understood
as meaning that at least one medium to be cooled, such as exhaust
gas and/or boost air, is cooled by a coolant such as a fluid
containing water and/or a liquid such as cooling water, with this
fluid containing water and/or the liquid such as cooling water
being cooled by some other cooling medium, such as ambient air.
[0169] The at least one boost-air cooler in another embodiment is
cooled directly and the at least one exhaust-gas cooler is cooled
indirectly, or vice versa the at least one boost-air cooler in
another embodiment is cooled indirectly, and the at least one
exhaust-gas cooler is cooled directly.
[0170] In order to improve the heat transfer, in a further
embodiment, at least two circuits, in particular two, three, four
or more circuits, for the first medium are stacked one behind the
other, that is to say in particular they are stacked in the
direction A and/or in the stacking direction in which the plates
are stacked, which in particular farms an angle 0.degree. to
90.degree. with the direction A. For example, the two, three, four
or more than four circuits may have flow passing through them in
opposite directions or in the same direction, or at an angle of
0.degree. to 90.degree. to the second fluid, in particular to the
flow direction of the second fluid.
[0171] If the at least two circuits, in particular two, three, four
or more than four circuits, for the first medium are arranged one
behind the other, that is to say in particular in the direction A,
at least one high-temperature circuit is arranged first flowing in
the direction A, and is at a higher temperature than an at least
second low-temperature circuit. In particular, the temperature
difference between the high-temperature circuit and the
low-temperature circuit is 10K to 100K, in particular 30K to 80K,
more particularly 30K to 60K.
[0172] The high-temperature circuit is at temperatures between
70.degree. C. and 100.degree. C., in particular between 80.degree.
C. and 95.degree. C., in particular in the operating state. The low
temperature is at temperatures between 10.degree. C. and 70.degree.
C., in particular between 20.degree. C. and 60.degree. C., in
particular between 30.degree. C. and 65.degree. C., and more
particularly between 40.degree. C. and 50.degree. C., in particular
in the operating state.
[0173] In this way, the exhaust gas that is fed back and/or the
boost air or at least one medium to be cooled is cooled in two,
three, four or more stages.
[0174] The at least two circuits, in particular two, three, four or
more circuits for the first medium are in the form of at least one
U-flow circuit and/or at least one I-flow circuit. For example, at
least two I-flow circuits or at least two U-flow circuits are
arranged in series, in particular one after the other. In another
example, at least one U-flow circuit follows at least one I-flow
circuit, or vice versa. In particular, when at least two U-flow
circuits are provided, the coolant connections for the at least two
circuits are in one example arranged on one side of the cooler, for
example at the top or bottom in the stacking direction of the
plates, or at an angle of between 0.degree. and 90.degree. to the
stacking direction.
[0175] In another example, the forward flow takes place in at least
one high-temperature circuit, and the return flow in the at least
one low-temperature circuit, or vice versa.
[0176] Furthermore, in another embodiment, a combination valve is
integrated in the at least one heat exchanger, for example in the
exhaust-gas heat exchanger and/or in the at least one boost-air
cooler and/or in the at least one oil cooler and/or in the at least
one coolant cooler and/or in the at least one coolant condenser for
a climate-control system and/or in the at least one gas cooler for
a climate-control system and/or in the at least one coolant
vaporizer for a climate-control system and/or in the at least one
cooler for cooling electronic components, in particular integrated
in the housing of the heat exchanger, and/or formed integrally with
it. The combination valve combines the function of at least one
exhaust gas feedback valve for open-loop and/or closed-loop control
of the fed-back exhaust gas or exhaust gas/air mixture, and/or the
function of at least one bypass valve, in particular a bypass flap,
for bypassing exhaust gas that has been fed back around the at
least one heat exchanger, in particular the exhaust-gas heat
exchanger and/or one of the other heat exchangers mentioned further
above, so that a medium which is fed back, in particular exhaust
gas and/or air, is not cooled in the at least one heat exchanger,
in particular the exhaust-gas heat exchanger and/or one of the
other heat exchangers mentioned further above. A combination valve
such as this is disclosed in the unpublished DE 10 2005 034 136.5,
the unpublished DE 10 2005 041 149.5, the unpublished DE 10 2005
041 150.9, the unpublished DE 10 2005 034 135.7 and in the
published DE 103 21 636, the published DE 10321637 and the
published DE 10 2005 041 146, whose entire content is hereby
expressly regarded as disclosed.
[0177] The features of various exemplary embodiments can be
combined with one another as required. The invention can also be
used for fields other than those described.
* * * * *