Heat Exchanger for an Internal Combustion Engine, Having a Stiffening Element in the Region of a Join Between Two Partitions, and Internal Combustion Engine Having a Heat Exchanger

Abstract

A heat exchanger for an internal combustion engine transfers heat between fluids, and includes a housing which has a housing wall and a housing interior that is bounded at least in certain regions by the housing wall. The housing interior has a fluid inlet region for the introduction of a first of the fluids into the housing interior, and a fluid outlet region for discharging the first fluid from the housing interior. The heat exchanger has at least two partitions which are at least predominantly accommodated in the housing interior and which are connected to the wall of the housing at at least one connection region. In order to separate the fluids from one another, the partitions bound, at least in certain regions, a fluid receiving space through which a second of the fluids can be made to flow. The partitions are connected to one another at least at a joining region that is assigned to the fluid inlet region and that adjoins the fluid receiving space in a main flow direction of the first fluid. The heat exchanger additionally has a stiffening element which, in order to stiffen a stiffening portion of the joining region adjoining the connection region, is arranged at the joining region and is configured to brace the stiffening portion at least against a buckling load arising from a change in length in the event of a temperature-induced change in length of the joining region.

Claims

1.-10. (canceled)

11. A heat exchanger for an internal combustion engine for transferring heat between at least two fluids, comprising: a housing having a housing wall and a housing interior which is delimited at least in regions by the housing wall, and which has a fluid inlet region for introducing a first fluid of the at least two fluids into the housing interior and a fluid outlet region for discharging of the first fluid from the housing interior; at least two partitions which are accommodated at least predominantly in the housing interior and which are connected to the housing wall of the housing in at least one connecting region, and which, in order to separate the at least two fluids from one another, at least in regions delimit a fluid-receiving space through which a second fluid of the at least two fluids flows, wherein the at least two partitions are connected to one another at least at a joining region which is assigned to the fluid inlet region and adjoins the fluid-receiving space in a main fluid flow direction of the first fluid; at least one stiffening element which, in order to stiffen at least in regions at least one stiffening portion of the joining region adjoining the connecting region, is arranged at the joining region and is configured to brace the stiffening portion at least against a buckling load induced by a length change in an event of a temperature-related length change of the joining region.

12. The heat exchanger according to claim 11, wherein the stiffening element at least in regions surrounds the at least two partitions at the stiffening portion.

13. The heat exchanger according to claim 11, wherein the stiffening element clamps the at least two partitions at the stiffening portion.

14. The heat exchanger according to claim 11, wherein the joining region comprises a joining region portion without a stiffening element.

15. The heat exchanger according to claim 14, wherein the stiffening element has a tapering region at which the stiffening element tapers in a direction of the joining region portion without the stiffening element.

16. The heat exchanger according to claim 11, wherein the stiffening element is connected by material bonding to at least one of the at least two partitions.

17. The heat exchanger according to claim 11, wherein the at least two partitions are connected to the housing wall at the connecting region in a T-shaped butt joint.

18. The heat exchanger according to claim 11, wherein the stiffening element is connected by material bonding to at least one of the at least two partitions and/or to the housing wall at the connecting region.

19. An internal combustion engine comprising a heat exchanger according to claim 11.

20. The internal combustion engine according to claim 19, wherein the heat exchanger is configured as an exhaust gas cooler of the internal combustion engine.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0036] FIG. 1 is a perspective sectional illustration of a heat exchanger (shown in extract) of an internal combustion engine, which serves for transfer of heat between two fluids, of which a first fluid is an exhaust gas and a second fluid a coolant of the internal combustion engine, wherein the internal combustion engine, illustrated in highly abstract form, is assigned to a vehicle, also illustrated in highly abstract form;

[0037] FIG. 2 is an enlarged view of a segment of the heat exchanger shown in FIG. 1; and

[0038] FIG. 3 is an enlarged illustration of a region A, outlined in dotted lines in FIG. 2, which shows a stiffening element in enlarged perspective view.

DETAILED DESCRIPTION OF THE DRAWINGS

[0039] FIG. 1 shows a schematic illustration of a motor vehicle K, with an also schematically illustrated internal combustion engine 100 which is configured to drive the motor vehicle K. The internal combustion engine 100 comprises a heat exchanger 10 which is configured as an exhaust gas cooler, namely an EGR cooler of the internal combustion engine 100. By means of the heat exchanger 10, a so-called cooled exhaust gas recirculation is possible during operation of the internal combustion engine 100. FIG. 2 shows an enlarged illustration of a segment of the heat exchanger shown in FIG. 1

[0040] The heat exchanger 10 serves to transfer heat between two fluids. A first fluid of the two fluids is in this case an exhaust gas, while a second fluid of the two fluids is in this case a coolant, for example in the form of a water-antifreeze mixture.

[0041] The heat exchanger 10 (here the EGR cooler) comprises a housing 20 with at least one housing wall 22. In this case, the housing wall 22 is formed as a sheet metal part and may also be described as a cooling jacket.

[0042] The housing wall 22 peripherally delimits a housing interior 24 of the housing. The housing interior 24 has a fluid inlet region 30 for introduction of the first fluid into the housing interior 24, and a fluid outlet region for discharge of the first fluid from the housing interior 24. The fluid outlet region (not shown further here) is arranged downstream of the fluid inlet region in a main fluid flow direction x of the first fluid. The main fluid flow direction x corresponds to a longitudinal direction of the heat exchanger 10. In other words, on correct use of the heat exchanger 10, the first fluid flows through the housing interior 24 in the longitudinal direction of the heat exchanger 10.

[0043] As also evident from FIG. 1 and FIG. 2, in the present case the heat exchanger is configured as a plate heat exchanger.

[0044] The plates of the heat exchanger 10 are formed by pairs of interconnected partitions 40, 50, namely a first partition 40 and a second partition 50, in the present case each formed as sheet-metal half shells. A plate is thus formed by the first partition 40 and the second partition 50, wherein the heat exchanger 10 has a plurality of such plates, as evident in FIG. 1. Only a single plate formed by the two partitions 40, 50 is discussed below, but in principle the statements below also apply to the other plates of the heat exchanger 10.

[0045] The partitions 40, 50 are received in the housing interior 24 and connected to the housing wall 22 at connecting regions 60, 62 lying opposite one another in a height (vertical) direction z of the heat exchanger 10. The first partition 40 has respective partition regions 42 opposite one another in the height direction z, while the second partition 50 has partition regions 52 opposite one another in the height direction z. The respective partition regions 42, 52 are molded onto the housing wall 22. In other words, at the corresponding connecting regions 60, 62, the partition regions 42, 52 run at least largely parallel to the housing wall 22 and in this case also parallel to one another, and are connected to the housing wall 22 at the connecting regions 60, 62 by substance bonding, in particular by a solder connection.

[0046] The partitions 40, 50 serve to separate the fluids from one another and, on correct use of the heat exchanger 10, at least in regions delimit a fluid-receiving space 70 through which the second fluid (here coolant) flows. The fluid-receiving space 70 is also delimited by the housing wall 22 in regions, namely in the height direction z of the heat exchanger 10 oriented perpendicularly to the main fluid flow direction x. The fluid-receiving space 70 is covered by the partitions 40, 50 in all FIGS. 1 to 3 and therefore not visible, but it is quite clear how the respective partitions 40, 50 formed as sheet-metal half shells may delimit the fluid-receiving space 70. Thus each of the sheet-metal half shells (partitions 40, 50) may delimit around half the fluid-receiving space 70.

[0047] The pairs of partitions 40, 50 are in each case connected together by substance bonding, and here soldered, at least at a joining region 80 assigned to the fluid inlet region 30 and adjoining the fluid-receiving space 70 in the main fluid flow direction x of the first fluid. A gap 84 extending over the joining region 80 between the partitions 40, 50 is filled with metal solder, whereby the partitions 40, 50 are soldered together and the gap 84 sealed against an undesired escape of the second fluid (coolant, in particular cooling water) from the fluid-receiving space 70 extending between the partitions 40, 50. In addition, the partitions 40, 50 are also connected together at a further joining region opposite the joining region 80 in the main fluid flow direction x and assigned to the fluid outlet region, but this is not however visible in all FIGS. 1 to 3 since the fluid outlet region is not shown.

[0048] The respective partitions 40, 50 are oriented towards the respective partition regions 42, 52 at the common joining region 80 at an angle, namely in this case a right angle (90°). The partitions 40, 50 are thereby connected to the housing wall 22 at the connecting regions 60, 62 in a T-shaped butt joint, as particularly evident in FIG. 2.

[0049] It is clear from FIG. 2 and FIG. 3 that the heat exchanger 10 comprises a plurality of stiffening elements 90 which are arranged at the joining region 80 for at least regional stiffening of stiffening portions 86 of the joining region 80 adjoining the connecting regions 60, 62. The stiffening elements 90 are designed to brace the respective stiffening portions 86 at least against a buckling load induced by a change of length in the event of a temperature-related length change of the joining region 80. The bracing against buckling load may in particular prevent a lateral buckling in the form of a bulging or wavy deformation in the region of the stiffening portions 86. An illustration of the stiffening element 90 has been omitted in FIG. 1 purely for reasons of clarity.

[0050] In the present case, for each joining region 80 and hence each plate (comprising the partitions 40, 50), two stiffening elements 90 are arranged on stiffening portions 86 lying opposite one another in the height direction z. One of the stiffening portions 86 is assigned to the connecting region 60, and another of the stiffening portions 86 is assigned to the second connecting region 62. Thus one of the stiffening elements 90 is arranged at the connecting region 60, and one of the stiffening elements 90 (in the present example, opposite in the height direction z) is arranged on the connecting region 62.

[0051] The stiffening elements 90 surround the partitions 40, 50 at the respective stiffening portions 86 in regions, whereby an effective stiffening can be achieved at both partitions 40, 50.

[0052] In addition, the stiffening elements 90 clamp the partitions 40, 50 at the stiffening portion 86. In other words, the stiffening elements 90 each exert a clamping force on the partitions 40, 50.

[0053] It is evident from FIG. 2 that the joining region 80 comprises a joining region portion 82 without stiffening element. The joining region portion 82 extends between the mutually opposite stiffening portions 86. If a temperature-related length change of the joining region 80 occurs on correct use of the heat exchanger 10, the design of the joining region portion 82 without stiffening element allows a slight deformation caused by length change, for example in the form of a wave-like local buckling, and hence limits this in targeted fashion to this joining region portion 82, while buckling and associated mechanical stress loading in the region of the stiffening portions 86 and at the connecting regions 60, 62 can be prevented by the stiffening elements 90.

[0054] The stiffening elements 90 each have a tapering region 98 at which the respective stiffening elements 90 taper in the direction of the joining region portion 82 without stiffening element. It is clear from FIG. 3 that because of their taper, the stiffening elements 90 are pointed in the direction of the joining region portion 82. The tapering region 98 may preferably extend over the entire length of the stiffening elements 90, as can be seen in FIG. 3 in which the tapering region 98 extends over the entire length of the stiffening elements 90 in the height direction z.

[0055] The stiffening elements 90 in the present case are formed as hollow cuboids at least in regions. Each stiffening element 90 has two side wall regions 92, 94 lying opposite one another in a direction y different from the main fluid flow direction x. Of these side wall regions 92, 94, a first side wall region 92 braces the first partition 40 along the stiffening portion 86 and preferably also at one of the connecting regions 60, 62. A second side wall region 94 of the side wall regions 92, 94, lying opposite the first side wall region 92 in the direction y, braces the second partition 50 along the stiffening portion 86 and preferably also at one of the connecting regions 60, 62, as shown in FIG. 3. The side wall regions 92, 94 are integrally connected together via an end wall region 96 of the respective stiffening element 90. The end wall region 96 comprises an end face 97 facing the main fluid flow direction x (see FIG. 3). In the present case, the direction y corresponds to a transverse direction of the heat exchanger 10.

[0056] The direction y is oriented perpendicularly to a central plane M, to which the partitions 40, 50 may be oriented at least substantially parallel. The central plane M in the present case is spanned by the main fluid flow direction x and the height direction z. The main fluid flow direction x (longitudinal extent of the heat exchanger 10), the direction y (transverse direction of the heat exchanger 10), and the height direction z are each oriented perpendicularly to one another.

[0057] The stiffening elements 90 are each connected by substance bonding, in particular soldered, to the partitions 40, 50.

[0058] The respective stiffening elements 90 are connected by substance bonding to the partitions 40, 50 at the respective connecting regions 60, 62, and are at least indirectly connected to the housing wall 22. An at least indirect connection here means that the stiffening elements 90 may be substance-bonded to the partitions 40, 50 at the partition regions 42, 52, wherein the partition regions 42, 52 are in turn substance-bonded to the housing wall 22.

[0059] The stiffening elements 90 are each provided and configured to prevent any buckling, for example in the form of wave formation or bulging, resulting from mechanical stresses induced by length change at the connecting regions 60, 62, following a temperature-related length change of the joining region 80. The stiffening elements 90 thus allow a particularly failure-proof transfer of heat between the fluids.

[0060] The partitions 40, 50 are connected together by substance bonding, namely soldered, along the entire joining region 80.

[0061] The partitions 40, 50 (sheet-metal half shells) may firstly be joined together at the joining region 80 and secondly to the housing wall 82 at the connecting regions 60, 62 during production of the present heat exchanger 10. Because of minimal solder widths in the design of the heat exchanger 10, the connecting regions 60, 62 constitute particularly stiff zones of the heat exchanger 10, in particular at the fluid inlet region 30.

[0062] The stiffening elements 90 may prevent an unacceptably high mechanical load, for example in the form of a thermal shock load, at the connecting regions 60, 62. The stiffening elements 90 prevent buckling of the partitions 40, 50, which are connected to the housing wall 22 with a T-shaped butt joint, at the stiffening portions 86, whereby excessive loads on the connecting regions 60, 62 can be prevented even under high transient flows of particularly hot exhaust gas (first fluid) through the housing interior 24. The stiffening elements 90 as a whole may form a targeted local reinforcement at which buckling is suppressed even under temperature-related length change.

[0063] The geometric design of the stiffening elements 90 leads to a targeted local increase in stiffness of the sheet-metal half shells (partitions 40, 50) in the joining region 80. By means of the stiffening elements 90, therefore, the soldered sheet-metal half shells are stiffened locally within limits, whereby thermal shock loads cause less deformation at the stiffening portions 86. The stiffening portions 86 constitute respective edge regions of the joining region 80 adjoining the connecting regions 60, 62. The stresses from thermal shock loads on the connecting regions 60, 62 as a whole are relieved.

[0064] In the present heat exchanger 10, the stiffening elements 90 help prevent any stress cracks induced by temperature-related length changes in the region of the connecting regions 60, 62. In addition, the stiffening elements 90 substantially reduce any sudden stiffness changes in the T-shaped butt joint connection and extend any crack propagation paths.

[0065] The stiffening elements 90 may in general, for ease of installation, also be configured as stiffening clips. The stiffening clips may then for example be latched onto at least one of the partitions 40, 50 or both partitions 40, 50 at the stiffening portion 86.

[0066] The stiffening elements 90 may be connected, preferably soldered, to the joining region 80 during production of the heat exchanger 10.

LIST OF REFERENCE SIGNS

[0067] 10 Heat exchanger [0068] 20 Housing [0069] 22 Housing wall [0070] 24 Housing interior [0071] 30 Fluid inlet region [0072] 40 First partition [0073] 42 Partition region [0074] 50 Second partition [0075] 52 Partition region [0076] 60 Connecting region [0077] 62 Second connecting region [0078] 70 Fluid-receiving space [0079] 80 Joining region [0080] 82 Joining region portion [0081] 84 Gap [0082] 86 Stiffening portion [0083] 90 Stiffening element [0084] 92 Side wall region [0085] 94 Second side wall region [0086] 96 End wall region [0087] 97 End face [0088] 98 Tapering region [0089] 100 Internal combustion engine [0090] K Motor vehicle [0091] M Central plane [0092] x Main fluid flow direction [0093] Y Direction [0094] z Height (vertical) direction