EP4018146A1 - Heat exchanger, in particular for a motor vehicle, and process for manufacturing such a heat exchanger - Google Patents

Abstract

The present invention relates to a heat exchanger comprising a bundle (3) for heat exchange between at least a first fluid (F1) and a second fluid (F2), the heat exchange bundle (3) being made up of at least two hollow elements (31) that are superposed and configured to respectively form a channel (35) inside of which the first fluid (F1) is intended to circulate, and to allow the circulation of the second fluid (F2) in a space (37) between the superposed hollow elements (31), at least one hollow element has a plurality of protuberances (5) extending within the space (37) for the circulation of the second fluid (F2), the protuberances (5) creating a link between two adjacent hollow elements (31), and at least a first hollow element (31a) and a second hollow element (31b) arranged facing one another are in fluid communication with one another via at least one hollow protuberance (5).

Description

Heat exchanger in particular for a motor vehicle and method of manufacturing such a heat exchanger

The present invention relates to the field of heat exchangers, in particular for motor vehicles, and to methods of manufacturing such heat exchangers.

Nowadays, heat exchangers equip large numbers of motor vehicles. These heat exchangers can for example be dedicated to cooling motors or batteries, or even to the operation of air conditioning systems.

Heat exchangers generally include a heat exchange bundle consisting of a set of superimposed hollow elements in which a first heat transfer fluid, such as glycol water or a refrigerant fluid, is intended to flow. This heat exchange bundle has a plurality of fins arranged between these hollow elements. These fins are configured to increase the heat exchange surface between the first coolant flowing inside the hollow elements and a second coolant, such as air, flowing between these hollow elements. However, such heat exchangers have a large number of parts and can be complex to assemble, in particular due to the mounting of the fins. Such a heat exchanger is for example described in document EP 2869015.

On the other hand, finned heat exchangers generate a certain thermal resistance for the exchange between the first coolant, such as refrigerant, and the second coolant, such as air. Indeed, the surface of the fins allowing to increase the exchange surface is not in direct contact with the two fluids. The heat exchanges between these two fluids with the heat exchangers of the prior art can therefore be improved.

From document US Pat. No. 3,757,856, a heat exchanger is known in which the hollow elements of the heat exchange bundle have protuberances or cavities so as to improve the exchange surfaces between the two fluids circulating in the heat exchanger. this heat exchanger. However, the heat exchanges between the first and second fluid within the heat exchange bundle described in this document can be improved.

The object of the present invention is to provide a heat exchanger having improved heat exchange capacities compared to those known from the prior art and having good mechanical strength.

Another objective of the present invention, different from the previous objective, is to provide a heat exchanger of which the number of parts constituting it is limited.

Another objective of the present invention, different from the preceding objectives, is to provide a heat exchanger which is simple and quick to assemble.

Another objective of the present invention, different from the preceding objectives, is to provide a method of manufacturing a heat exchanger which is simple, fast and inexpensive.

In order to achieve, at least partially, at least one of the aforementioned objectives, the present invention relates to a heat exchanger, in particular for a motor vehicle, comprising a heat exchange bundle between at least a first fluid and a second fluid, said heat exchange bundle being composed of at least two superimposed hollow elements and configured to respectively form a channel inside which the first fluid is intended to circulate and to allow the circulation of the second fluid in a space between the superimposed hollow elements , at least one hollow element of the heat exchange bundle has a plurality of protuberances extending in the space for the circulation of the second fluid, said protuberances making the connection between two adjacent hollow elements, and at least a first hollow element and a second hollow element arranged opposite one another are in fluid communication with one another by at least one protuberance hollow ance carried by at least one of the first and / or second hollow elements.

The possibility for the first fluid to pass from a hollow element to another hollow element through the protuberances connecting these hollow elements, allows a good homogenization of the temperature of this first fluid and also an improvement. heat exchanges between the first and second fluids. On the other hand, the presence of the protuberances allows disruption of the circulation of the second fluid through the heat exchange bundle. Thus, the heat exchanges between the first and second fluids are improved due to the protuberances connecting the hollow elements to one another and also allowing the circulation of the first fluid through certain hollow protuberances. In addition, the protuberances are configured to connect the hollow elements to one another, which also makes it possible to simplify the structure of the heat exchange bundle by making it possible in particular to limit the number of parts making up this heat exchange bundle.

The heat exchanger according to the present invention may further include one or more of the following features taken alone or in combination.

According to a first aspect, the hollow elements of the heat exchange bundle can be plates.

According to this first aspect, the heat exchange beam can be formed by a row of superimposed plates.

According to a second aspect, the hollow elements of the heat exchange bundle can be flat tubes.

According to this second aspect, the heat exchange bundle can be formed by at least one row of superimposed flat tubes.

The hollow elements can be made of a material having a thermal conductivity greater than or equal to 45 W.nrbK ^{· 1} at 20 ° C.

The hollow elements can be made of metal or of a metal alloy, in particular of aluminum.

According to a particular embodiment, the first hollow element can carry at least one hollow protuberance cooperating with an orifice made in the second hollow element arranged opposite the at least one hollow protuberance of the first hollow element, said hollow protuberance ensuring communication. fluidic between the first and second hollow elements and forming a sealed connection with the orifice. According to this particular embodiment, the first and second hollow elements alternately have a hollow protuberance and an orifice intended to cooperate with a hollow protuberance in a sealed manner in the assembled state of the heat exchange bundle.

According to another particular embodiment, the first and the second hollow elements can each have at least one hollow protrusion, the hollow protrusion carried by the first hollow element having an end cooperating with one end of the hollow protrusion carried by the second hollow element. and forming a sealed connection with this hollow protuberance of the second hollow element so as to allow fluid communication between the first and second hollow elements.

In one aspect, each channel for the circulation of the first fluid has a center and a periphery and at least one hollow protuberance allowing fluid communication between two adjacent hollow elements can be disposed at the level of the center of the channel.

According to one variant, the hollow elements may comprise transverse partitions obstructing a section of the channel so that the first fluid circulates between two adjacent hollow elements in fluid communication.

According to this variant, the transverse partitions can form at least one baffle for the circulation of the first fluid in the heat exchange bundle.

In one aspect, the plurality of protrusions carried by the at least one hollow member may be hollow protrusions allowing fluid communication between the first and the second hollow member.

According to a first particular embodiment, the hollow protuberances may have a shape of constant section, a first end of which is disposed in contact with a face of the hollow element carrying the protuberance and a second free end, disposed opposite to the first end and in contact with the adjacent hollow element. According to this first particular embodiment, the section of the hollow protuberance can be circular, oblong, or even parallelepiped.

According to a second particular embodiment, the hollow protuberances may have a shape of variable section, a first end of which is placed in contact with a face of the hollow element carrying the protuberance and a second free end, opposite the first end and disposed in contact with the adjacent hollow element, said first end having a section the area of which is greater than that of the second free end.

According to this second particular embodiment, the hollow protuberance may be of conical shape, the second end of which is flat or in the shape of a dome.

According to a variant of this second particular embodiment, the hollow protuberances have a leading wall and an end wall, the leading wall being the first in contact with the first fluid during the passage of this first fluid at the level of the hollow protuberance.

According to a particular embodiment of this variant, the hollow elements each have at least one hollow protuberance, the second free ends of which are in contact with one another, and these hollow protuberances have a central symmetry with respect to the center of the opening. hollow protuberances for the passage of the first fluid between a first and a second hollow element.

According to this variant, the leading wall of the hollow protuberance and the channel of the hollow element can form an angle of between 90 ° and 180 °, and in particular between 105 ° and 150 °.

Also according to this variant, the end wall of the hollow protuberance and the channel of the hollow element can form an angle of between 90 ° and 180 °, and in particular between 120 ° and 165 °.

Still according to this variant, the hollow element can have at least one transverse partition. The transverse partition can be arranged in the middle of the space defined between two hollow protuberances in the hollow element.

According to a particular embodiment, the heat exchange bundle may further comprise two end elements arranged parallel to the superimposed hollow elements and respectively on either side of the superposition of hollow elements, each end element having a face disposed opposite a face of a hollow element and defining a space between the end element and the hollow element to allow the circulation of the second fluid.

The face of the end element may be smooth and is configured to obstruct the openings of the second ends of the hollow protuberances disposed opposite the end element so as to form a tight connection between the hollow element and the adjacent element.

A subject of the present invention is also a method of manufacturing a heat exchanger as defined above comprising the following steps: producing hollow protuberances by stamping at least one face of a first hollow element, at least part of the hollow protuberances. hollow protrusions having an opening disposed at a second end opposite a first end disposed in contact with the first hollow member; formation of a stack comprising at least a first and a second superimposed hollow element, the face of the first hollow element having the hollow protuberances being arranged opposite a face of the second hollow element having orifices and so that the protuberances cooperate with the orifices; and heating and compressing the stack in order to allow the mechanical connection by brazing at least of the hollow protuberances carried by the first hollow element with the periphery of the orifices carried by the second hollow element in order to form a tight mechanical connection between the first and second hollow elements.

According to a particular embodiment, the orifices of the second hollow element may correspond to the opening of the second end of the protuberances carried by the second hollow element. According to a variant, the stack may further comprise two end elements arranged respectively on either side of the superposition of hollow elements and parallel to these hollow elements, said end elements having a face arranged facing each other. 'one face of the adjacent hollow element, said face of the end elements being smooth.

According to this variant, the hollow elements arranged facing the end elements may have hollow protuberances on their face arranged facing the end elements in order to allow the soldering of the end elements with the adjacent hollow elements and the formation of 'a tight mechanical connection between the hollow elements and the end elements.

Other characteristics and advantages of the present invention will emerge more clearly on reading the following description, given by way of illustration and not limitation, and the accompanying drawings in which:

[Fig. 1] Figure 1 is a schematic perspective view of a heat exchanger;

[Fig. 2] Figure 2 is a schematic partial perspective representation of a heat exchange bundle of the heat exchanger of Figure 1;

[Fig. 3A] FIG. 3A is a schematic perspective representation of a set of protuberances according to a first variant;

[Fig. 3B] FIG. 3B is a schematic perspective representation of a set of protrusions according to a second variant;

[Fig. 3C] FIG. 3C is a schematic perspective representation of a set of protuberances according to a third variant;

[Fig. 4A] FIG. 4A is a schematic perspective representation of a set of protrusions according to a fourth variant;

[Fig. 4B] FIG. 4B is a schematic perspective representation of a set of protuberances according to a fifth variant; [Fig. 5A] FIG. 5A is a schematic representation in cross section of two protuberances cooperating with one another according to a first embodiment;

[Fig. 5B] FIG. 5B is a schematic representation in cross section of two protuberances cooperating with one another according to a second embodiment;

[Fig. 6] Figure 6 is a schematic cross-sectional representation of two hollow elements of the heat exchange bundle of Figure 2 in fluid communication according to a first particular embodiment;

[Fig. 7] Figure 7 is a schematic cross-sectional representation of two hollow elements of the heat exchange bundle of Figure 2 in fluid communication according to a second particular embodiment;

[Fig. 8] Figure 8 is a schematic cross-sectional representation of two hollow elements of the heat exchange bundle of Figure 2 in fluid communication according to a third particular embodiment;

[Fig. 9] Figure 9 is a schematic representation in cross section of two hollow elements of the heat exchange bundle of Figure 2 in fluid communication according to a fourth particular embodiment;

[Fig. 10] Figure 10 is a schematic cross-sectional representation of a heat exchange bundle having hollow elements in fluid communication according to a fifth particular embodiment; and

[Fig. 11] Figure 11 is a schematic representation of a flowchart illustrating a method of manufacturing the heat exchanger of Figure 1.

Identical elements in the various figures bear the same references.

The following embodiments are examples. Although the description refers to one or more embodiments, this does not necessarily mean that each reference relates to the same embodiment, or that the characteristics apply only to one embodiment. Simple features of different modes embodiments can also be combined and / or interchanged to provide other embodiments.

In the present description, it is possible to index certain elements or parameters, such as for example first element or second element as well as first parameter and second parameter or even first criterion and second criterion etc. In this case, it is a simple indexing to differentiate and name elements or parameters or criteria that are similar but not identical. This indexing does not imply a priority of one element, parameter or criterion over another and such names can easily be interchanged without departing from the scope of the present description. This indexing does not imply an order in time, for example, to assess such or such criteria.

In the following description, "thermal conductivity" is understood to mean the energy, or quantity of heat, transferred per unit area and time, expressed in watts per meter-Kelvin (W.m-fK).

Then, by "fluid" is meant in the following description, a body whose molecules have little adhesion and can slide freely with respect to each other (in the case of liquids) or move independently of one another (in the case of liquids). the case of gases), so that the body takes the form of the vessel which contains it.

Referring to Figure 1, there is shown a heat exchanger 1 in particular for a motor vehicle. This heat exchanger 1 comprises a heat exchange bundle 3 between at least a first heat transfer fluid Fl and a second heat transfer fluid F2 (visible in FIG. 2). The heat exchange bundle 3 is made up of at least two hollow elements 31 superimposed. Each hollow element 31 forms at least one channel 35 (visible in FIG. 2) inside which the first fluid F1 is intended to circulate. The heat exchanger 1 further comprises a first 11 and a second 13 manifold boxes. The first 11 and second 13 manifolds are arranged at the ends of the hollow elements 31 and together with the heat exchange bundle 3 form the heat exchanger 1. The first manifold 11 has for example an inlet 11a in order to supply the elements. hollow 31 in the first fluid Fl and the second manifold 13 has for example an outlet 13a in order to allow the circulation of first fluid Fl in a circuit (not shown) allowing the return of this first fluid Fl at the level of the first manifold 11. This first heat transfer fluid Fl can in particular be a liquid, such as for example glycol water or a refrigerant fluid . These first 11 and second 13 header boxes are attached to the heat exchange bundle 3 in order to form the heat exchanger 1. These first 11 and second 13 header boxes can be fixed to the heat exchange bundle 3 by brazing or by a mechanical connection, in particular by crimping, for example. The superimposed hollow elements 31 of the heat exchange bundle 3 may be plates in order to form a plate heat exchanger 1, or else be flat tubes in order to form a tube heat exchanger 1. The heat exchange bundle 3 can therefore be produced by a row of superimposed plates or alternatively by at least one row of superimposed flat tubes. In the case where the heat exchange bundle 3 has more than one row of flat tubes, these rows are arranged side by side in the direction of circulation of the second fluid F2 (shown in FIG. 2). The hollow elements 31 superimposed on the heat exchange bundle 3 can in particular be made of a material having a thermal conductivity greater than or equal to 45 W.nrLK · ¹ at 20 ° C. Typically, these hollow elements can be made of metal or of a metal alloy, and in particular of aluminum. Such thermal conductivity for the material constituting the hollow elements 31 makes it possible to ensure good heat transfers between the first Fluid F1 and the second F2 in this heat exchange bundle 3 in order in particular to allow heat exchanges of the first fluid F1.

Referring to Figures 1 and 2, the hollow elements 31 are also configured to allow the circulation of the second fluid F2 in a space 37 between the hollow elements 31 to allow heat exchange between the first F1 and the second fluid F2 during operation. of this heat exchanger 1. The second coolant F2 may for example be air intended to circulate between the hollow elements 31 in order to exchange thermal energy with the first fluid Fl circulating inside the hollow elements 31 for example.

According to the particular embodiment of FIG. 2, there is shown a hollow element 31 having two channels 35 each comprising a center and a periphery. According to other alternatives, the hollow element 31 may have a different number of channels 35. Referring to Figures 1 and 2, at least one of the hollow elements 31 of the heat exchange bundle 3 has a plurality of protrusions 5. The protrusions 5 extend in the space 37 defined for the circulation of the second fluid F2. Such an arrangement of the protuberances 5 in the space 37 defined for the passage of the second fluid F2 makes it possible to create disturbances in the flow of the second fluid F2 through the heat exchange bundle 3, which allows, among other things, better homogenization of the temperature of this second fluid F2 and an improvement in the heat exchanges between the first F1 and the second F2 fluids circulating in the heat exchange bundle 3. This disturbance of the flow of the second fluid F2 in the space 37 may in particular consist of a reduction in its speed or even a disturbance in its direction of circulation allowing better homogenization of its temperature. On the other hand, the protuberances 5 form the connection between two adjacent hollow elements 31. By adjacent elements is meant here two elements arranged opposite one another. In addition, at least a first hollow element 31a and a second hollow element 31b arranged opposite one another are in fluid communication with one another by at least one hollow protuberance 5 carried by at least one of the hollow elements. first 31a and / or second 31b hollow elements 31.

According to the particular embodiment of Figure 1, the heat exchange bundle 3 can further include two end elements 38, 39 arranged parallel to the hollow elements 31 superimposed and respectively on either side of the superposition of hollow elements 31. Each end element 38, 39 has a face disposed opposite a face of a hollow element 31 and define a space 37 'between the end element 38, 39 and the hollow element 31 to allow the circulation of the second fluid F2. These end elements 38, 39 can be made by a plate, for example made of metal or a metal alloy, such as for example aluminum or an aluminum alloy. According to a particular embodiment, the material constituting the end elements 38, 39 is identical to that forming the hollow elements 31.

According to the particular embodiment of FIG. 2, the protuberances 5 are formed directly on the faces of the hollow elements 31. According to this particular embodiment, the protuberances 5 can be produced by deformation of a surface of the hollow elements 31. Referring to Figures 2 to 5B, the protuberances 5 have a first end 51 disposed in contact with the face of the hollow element 31 which carries the protuberance 5 and a second free end 53, opposite the first end 51, intended to be in contact with the hollow element 31 or the adjacent end element 38, 39 (visible in FIG. 1). The term “adjacent element” is understood here to mean an element of the heat exchange bundle 3 arranged opposite a face of a hollow element 31. An adjacent element can therefore be another hollow element 31, or else an end element 38. , 39. The second free end 53 of the hollow protuberances 5 has an opening configured to provide fluid communication between the first 31a and the second 31b hollow elements.

With reference to FIGS. 3A to 3C, there is shown the hollow protuberances 5 according to a first variant. According to this first variant, the hollow protuberances 5 may have a shape of constant section. By shape of constant section, it is understood here that the hollow protuberance 5 has a constant diameter over the whole of its length, that is to say over the whole of the space 37, 37 'arranged between the elements. 31, 38, 39 for the passage of the second fluid F2 in which it extends. According to the different embodiments shown with reference to Figures 3A to 3C, there is shown two hollow protuberances 5, the second free ends 53 having an opening for the passage of the first fluid F1 are respectively arranged in contact with each other and form a waterproof connection. Such an arrangement of the hollow protuberances 5 corresponds to that described above with reference to the second particular embodiment and can offer resistance to deformations associated with the passage of the second fluid F2 in the space 37, 37 ’significant. More particularly according to this first variant, the section of the hollow protuberance 5 may be oblong (FIG. 3A), parallelepiped (FIG. 3B), or even circular (FIG. 3C).

With reference to FIGS. 4A and 4B, there is shown the hollow protuberances 5 according to a second variant. According to this second variant, the hollow protuberances 5 may have a shape of variable section. By shape of variable section is meant here that the hollow protuberance 5 has a variable diameter over the whole of its length, that is to say over the whole of the space 37, 37 'arranged between the elements 31. , 38, 39 for the passage of the second fluid F2 in which it extends. The first end 51 of the hollow protuberances 5 has an area greater than that of the second free end 53. According to the different embodiments shown with reference to FIGS. 4A and 4B, there is shown two hollow protuberances 5, the second free ends 53 having an opening for the passage of the first fluid F1 are respectively arranged in contact with each other. Thus, such an arrangement of the hollow protuberances 5 also corresponds to the second particular embodiment described above. Such hollow protuberances 5 can make it possible to limit the reduction in the flow speed of the second fluid F2 in the space 37, 37 'defined between a hollow element 31 and an adjacent element 31, 38, 39 while disturbing the flow of water. this second fluid F2 in the space 37, 37 'and the circulation of the first fluid F1 inside the hollow elements 31. More particularly according to this second variant, the hollow protuberances 5 may have a conical shape having a second free end 53 plane (Figure 4A), or a dome shape (Figure 4B).

With reference to FIGS. 3A to 4B, the shape of the hollow protuberances 5 may be chosen as a function of the stresses which they may be subjected to during the operation of the heat exchanger 1 or even during the brazing of the bundle of. heat exchange 3. The shape of these hollow protuberances 5 can also be chosen as a function of the disturbances of the flow of the second fluid F2 and / or of the first fluid F1 (visible in FIG. 2) desired in the space 37, 37 '(visible especially in Figure 1).

Furthermore, with reference to Figures 5A and 5B, there is shown a sectional view of two protuberances 5 cooperating with each other at their second free end 53 to allow their joining by brazing to form a mechanical connection between the first 31a and second 31b hollow elements having these protuberances 5 arranged facing each other. According to the particular embodiment of FIG. 5A, the protuberances 5 have a contact zone 54 at the level of the periphery of their second free ends 53. This contact zone 54 makes it possible to ensure the brazing between these second free ends 53 to allow the formation of the heat exchange bundle 3 (in particular visible in FIG. 3). According to a particular embodiment, this contact zone 54 may have a length greater than or equal to 0.5 mm. This particular embodiment is described here for two protuberances 5 cooperating with one another. However, according to a variant not shown here, the contact zone 54 of the second free end 53 of a protuberance 5 can cooperate with the periphery of a orifice carried by the face of a hollow element 31 disposed opposite this protuberance 5. On the other hand, according to the particular embodiment of FIG. 5B, the second free ends 53 of the protuberances 5 carried respectively by a first 31a and a second hollow elements 31b and arranged opposite one another can be nested in order to allow the brazing of these second free ends 53 and thus the formation of the mechanical connection to form the heat exchange bundle 3.

The assembly of the heat exchange bundle 3 by brazing ensures good mechanical retention of this heat exchange bundle 3. Furthermore, the protuberances 5 occupy the space 37, 37 'for the passage of the second fluid F2. . In the case of the heat exchangers of the prior art, this space was occupied by the presence of fins arranged between the hollow elements 31. The presence of the protuberances 5 therefore makes it possible to limit the number of constituents of the heat exchange bundle 3. which makes it possible in particular to simplify its structure and its assembly by eliminating the presence of the fins known from the prior art. Such a heat exchange bundle 3 therefore has fairly low production costs while ensuring good mechanical strength thereof. Alternatively or in addition, such a mechanical connection of the heat exchange bundle 3 is also possible when the latter has the end elements 38, 39, one face of which is placed opposite the second free ends 53 of the protuberances 5, possibly hollow, and thus defining the space 37 'for the passage of the second fluid F2. On the other hand, this face of the end elements 38, 39 is smooth and configured to obstruct the openings of the second free ends 53 of the hollow protuberances 5 arranged opposite the end element 38, 39 so as to form an opening. sealed connection between the hollow element 31 and the adjacent element 31, 38, 39.

According to a first particular embodiment shown with reference to FIG. 6, a first hollow element 31a can carry at least one hollow protuberance 5 cooperating with an orifice 36 made in a second hollow element 31b disposed opposite this hollow protuberance 5 of the first hollow element 31a. The second free end 53 of this hollow protuberance 5 ensures fluid communication between the first 31a and second 31b hollow elements for the first fluid F1 and forms a sealed connection with the orifice carried by the second hollow element 31b. According to the particular embodiment of FIG. 6, the first hollow element 31a has the hollow protuberances 5 and the second hollow element 31b has the orifices in order to allow fluid communication between these first 31a and second 31b hollow elements and also the formation of the sealed mechanical connection between these hollow elements 31a, 31b.

According to a variant of this first particular embodiment not shown here, the first 31a and second 31b hollow elements may alternately have a hollow protuberance 5 and an orifice 36. This orifice 36 is intended to cooperate with the second free end 53 of a hollow protuberance 5 carried by the face of the hollow element 31 disposed opposite this orifice 36. Furthermore, the connection between the hollow protuberance 5 and the orifice 36 is a sealed mechanical connection, which can in particular be produced by brazing .

According to a second particular embodiment shown with reference to FIG. 7, the first 31a and the second 31b hollow elements each have at least one protuberance 5, the second free end 53 of the hollow protuberance 5 carried by the first cooperating hollow element 31a. with the second free end 53 of the hollow protuberance 5 carried by the second hollow element 31b. These second free ends 53 of the hollow protuberances 5 carried by the first 31a and second 31b hollow elements form a sealed connection so as to allow fluid communication between the first 31a and second 31b hollow elements.

According to these first and second embodiments, the first fluid F1 exhibits turbulences T at the level of the first ends 51 of the hollow protuberances 5. These turbulences T related to the passage of the first fluid F1 at least at the level of the first ends 51 of the protuberances 5 allows a disturbance of the flow of this first fluid F1 in the hollow element 31, thus contributing to an improvement in the homogenization of the temperature of this first fluid F1 and therefore heat exchanges between the first F1 and the second fluid F2. On the other hand, the first fluid F1 can pass from the first hollow element 31a to the second hollow element 31b and vice versa by passing through one of the protuberances 5. In addition, according to these first and second particular embodiments, the plurality of protrusions 5 carried by at least one hollow element 31 are hollow protuberances 5 allowing fluid communication between the first 31a and the second 31b hollow elements. Thus, these hollow protuberances 5 providing fluid communication between the first 31a and second 31b hollow elements allow the first fluid F1 to pass from the first hollow element 31a to the second hollow element 31b and reverse. Such a displacement of the first fluid F1 allows agitation of the latter at least at the level of the hollow protuberance 5, thus contributing to an improvement in the homogenization of its temperature. In addition, such a disturbance of the flow of the first fluid F1 allows an improvement in its heat exchanges with the second fluid F2 circulating in the space 37 between two adjacent hollow elements 31.

On the other hand, according to a third particular embodiment shown with reference to FIG. 8, the hollow elements 31 may comprise transverse partitions 9. The transverse partitions 9 obstruct a section of the channel 35 so that the first fluid F1 circulates between two. hollow elements 31 adjacent and in fluid communication. These transverse partitions 9 therefore allow the formation of a baffle for the first fluid F1. This baffle imposes the circulation of the first fluid F1 between the first hollow element 31a and the second hollow element 31b and vice versa. According to the particular embodiment of FIG. 8, the hollow elements 31 have transverse partitions 9 arranged staggered and between each hollow protuberance 5 in order to maximize the passages of the first fluid F1 between the first 31a and second 31b hollow elements in order to have a good homogenization of its temperature and thus improve the heat exchanges that this first fluid F1 can have with the second fluid F2 within the heat exchange bundle 3. According to an alternative not shown here, the hollow elements 31 may have a number lower transverse partitions 9 and more particularly more spaced from each other within the same hollow element 31.

Referring to Figure 9, there is shown a fourth embodiment of the hollow protuberances 5. This fourth embodiment makes it possible in particular to limit the pressure drops associated with the passage of the first fluid F1 between the first 31a and second 31b hollow elements. According to this fourth embodiment, the first 31a and second 31b hollow elements each have hollow protuberances 5 arranged facing each other. On the other hand, these hollow protuberances 5 have a variable section. More particularly, the hollow protuberances 5 have a leading wall 55 and an end wall 57. According to this fourth particular embodiment, the leading wall 55 of the hollow protuberance 5 is the first encountered in the direction of. circulation of the first fluid F1. According to this fourth particular embodiment, the leading wall 55 of the hollow protuberance 5 and the channel 35 of the hollow element 31 form an angle a of between 0 ° (limit excluded) and 90 ° (limit excluded), and in particular between 15 ° and 60 °. On the other hand, the end wall 57 of the hollow protuberance 5 and the channel 35 of the hollow element 31 form an angle b between 90 ° and 180 ° (limits excluded), and in particular between 105 ° and 150 ° . According to the particular embodiment of FIG. 9, each of the first 31a and second 31b hollow elements has hollow protuberances 5, the second free ends 53 of which are arranged opposite each other in order to ensure the mechanical connection, in particular by brazing. , of these first 31a and second 31b hollow elements. According to this particular embodiment, these second free ends 53 have an opening in order to allow the passage of the first fluid F1 from the first hollow element 31a to the second hollow element 31b and vice versa. Furthermore, these hollow protuberances 5 facing each other have a central symmetry with respect to the center of the opening for the circulation of the first fluid F1 between these first 31a and second 31b hollow elements.

On the other hand, according to the particular embodiment of FIG. 9, the hollow elements 31 also have transverse partitions 9 connecting the walls 35a of the channel 35 to one another. According to this particular embodiment, these transverse partitions are arranged staggered in the first 31a and second 31b hollow elements and separate the hollow protuberances 5 from one another. Furthermore, and still according to this particular embodiment, the transverse partitions 9 are arranged at the center of the length separating two hollow protuberances 5. According to other alternatives not shown here, the transverse partitions 9 may have a different spacing or even a different positioning within the first 31a and second 31b hollow elements.

According to a particular embodiment not shown here, each channel 35 for the circulation of the first fluid F1 has a center and a periphery and at least one hollow protuberance 5 allowing fluid communication between two adjacent hollow elements 31 is arranged at the level of the hollow. center of this channel 35.

On the other hand, according to a fifth particular embodiment shown with reference to FIG. 10, the heat exchange bundle 3 has more than two hollow elements 31, and more particularly a first 31a, a second 31b, and a third 31c. hollow elements, all in fluid communication via the protuberances 5. According to this fifth particular embodiment, the various hollow elements 31a, 31b, 31c have transverse partitions 9 configured to direct the flow in the direction of a channel 35 of an element hollow 31 particular. More particularly according to this fifth particular embodiment, the transverse partitions 9 are arranged so as to define flow directions for the first fluid F1 in directions orthogonal to the channels 35 of the hollow elements 31. Such an arrangement of the transverse partitions 9 increases. the path traveled by the first fluid F1 in the heat exchange bundle 3, which contributes to the improvement of the heat exchanges between the first Fl and second F2 fluids. Moreover, such a configuration of the heat exchange bundle 3 also makes it possible to limit the pressure drops linked to the various changes in direction of the first fluid F1.

Referring to Figure 11, there is shown a manufacturing process 100 of a heat exchanger 1 as described above. The manufacturing process 100 comprises a step of making E1 of hollow protuberances 5 on at least one face of a hollow element 31. At least part of these hollow protuberances 5 has an opening arranged at their second free end 53 opposite to it. their first end 51 disposed in contact with the first hollow element 31a. These hollow protuberances 5 can in particular be produced by stamping at least one face of this hollow element 31.

The manufacturing process 100 then implements a step of preparing a stack E2. This stack comprises at least a first 31a and a second 31b superimposed hollow elements. In addition, the face of the first hollow element 31a having the hollow protuberances 5 is arranged opposite the face of the second hollow element 31b having orifices and so that the hollow protuberances 5 cooperate with the orifices in order to allow fluid communication. between the first 31a and second 31b hollow elements. According to a particular embodiment, the orifices of the second hollow element 31b correspond to the opening of the second free ends 53 of the protuberances carried by the second hollow element 31b. Thus, it is possible to manufacture identical hollow elements 31 and then to make them cooperate to form the heat exchange bundle 3, which makes it possible in particular to facilitate the manufacturing process 100 of this heat exchanger 1. The manufacturing process 100 then implements a heating and compression step E3 of the stack in order to allow the mechanical connection by brazing at least of the hollow protuberances 5 carried by the first hollow element 31a with the periphery of the orifices carried by the second hollow element 31b in order to form a sealed mechanical connection between the first 31a and second 31b hollow elements. Thus, the manufacturing method 100 is simple and quick to implement, in particular due to the reduction in the constituent elements of the heat exchange bundle 3 of the heat exchanger 1.

According to an alternative, the stack may further comprise two end elements 38, 39 (visible in FIG. 1) arranged on either side of the superposition of hollow elements 31 and parallel to these hollow elements 31. Each end element 38, 39 has a face arranged opposite a face of a hollow element 31. This face of the end elements 38, 39 is smooth and intended to be brazed with the hollow elements 31 in the stack . According to a particular embodiment, the face of the hollow elements 31 arranged opposite the end elements 38, 39 has hollow protuberances 5 in order to form the space 37 'for the passage of the second fluid F2 and the brazing of the elements d. 'ends 38, 39 with the hollow elements 31 adjacent. These hollow protrusions 5 may have an opening for the passage of the first fluid F1. This opening is blocked by the end elements 38, 39 during the formation of the tight mechanical connection by brazing between the adjacent elements 31, 38, 39.

The manufacturing process 100 may include a final step of fixing (not shown) of the inlet 11 and outlet 13 (visible in FIG. 1) for the first fluid F1.

The various embodiments described above are examples provided by way of illustration and not by way of limitation. Indeed, it is quite possible for those skilled in the art to consider other shapes for the protuberances 5 than those described above without departing from the scope of the present description. On the other hand, those skilled in the art will be able to envisage a greater number of hollow elements 31 in fluid communication with one another without departing from the scope of the present description.

Thus, obtaining a heat exchanger 1 having improved heat exchange capacities compared to those known from the prior art and having a good mechanical strength while having a limited number of parts is possible thanks to the heat exchanger 1 having a heat exchange bundle 3 as defined above. In particular, the presence of protuberances 5 allows at least the various adjacent hollow elements 31 of the heat exchange bundle 3 to be joined together and allows an increase in the heat exchange surface area improving the exchanges between the first F1 and second F2 fluids. On the other hand, the joining of the various adjacent hollow elements 31 of this heat exchange bundle 3 by brazing at the level of the protrusions 5 makes it possible to simplify the structure of the heat exchange bundle 3 and also to ensure good mechanical strength of this heat exchange bundle 3 and therefore the heat exchanger 1. In addition, the presence of hollow protuberances 5 allowing fluid communication between at least a first 31a and a second 31b hollow elements allows an improvement in the homogenization of the temperature of the first fluid F1 and therefore an improvement in its heat exchanges with the second fluid F2.

Claims

Claims 1. Heat exchanger (1), in particular for a motor vehicle, comprising a heat exchange bundle (3) between at least a first fluid (Fl) and a second fluid (F2), said heat exchange bundle (3) being composed by at least two hollow elements (31) superimposed and configured to respectively form a channel (35) inside which the first fluid (Fl) is intended to circulate and to allow the circulation of the second fluid (F2) in a space (37) between the superimposed hollow elements (31), characterized in that at least one hollow element (31) of the heat exchange bundle (3) has a plurality of protuberances (5) extending in the space ( 37) for the circulation of the second fluid (F2), said protuberances (5) making the connection between two adjacent hollow elements (31), and in that at least a first hollow element (31a) and a second hollow element (31b) arranged opposite each other are in fluid communication with each other through the ego ns a hollow protuberance (5) carried by at least one of the first (31a) and / or second (31b) hollow elements. 2. Heat exchanger (1) according to the preceding claim, characterized in that the first hollow element (31a) carries at least one hollow protuberance (5) cooperating with an orifice made in the second hollow element (31b) disposed opposite at least one hollow protuberance (5) of the first hollow element (31a), said hollow protuberance (5) ensuring fluid communication between the first (31a) and second (31b) hollow elements and forming a sealed connection with the orifice . 3. Heat exchanger (1) according to claim 1, characterized in that the first (31a) and the second (31b) hollow elements each have at least one protrusion (5) hollow, the protrusion (5) carried by the hollow. first hollow element (31a) having one end cooperating with one end of the hollow protuberance (5) carried by the second hollow element (31b) and forming a sealed connection with this hollow protuberance (5) of the second hollow element (31b) so as to allow fluid communication between the first (31a) and second (31b) hollow elements. 4. Heat exchanger (1) according to any one of the preceding claims, characterized in that the hollow elements (31) comprise transverse partitions (9) obstructing a section of the channel (35) so that the first fluid (Fl) circulates between two adjacent hollow elements (31) in fluid communication. 5. Heat exchanger (1) according to any one of the preceding claims, characterized in that the plurality of protrusions (5) carried by the at least one hollow element (31) are protrusions (5) hollow allowing communication. fluidic between the first (31a) and the second (31b) hollow elements. 6. Heat exchanger (1) according to any one of the preceding claims, characterized in that the hollow protuberances (5) have a shape of constant section, a first end (51) is disposed in contact with a face of the 'hollow element (31) carrying the protuberance (5) and a second free end (53), disposed opposite the first end (51) and in contact with the adjacent hollow element (31). 7. Heat exchanger (1) according to any one of claims 1 to 5, characterized in that the protuberances (5) have a shape of variable section, a first end (51) is disposed in contact with a face. of the hollow element (31) carrying the hollow protuberance (5) and a second free end (53), opposite to the first end (51) and disposed in contact with the adjacent hollow element (31), said first end ( 51) having a section whose area is greater than that of the second free end (53). 8. Heat exchanger (1) according to claim 7, characterized in that the protuberances (5) have a hollow leading wall (55) and an end wall (57), the leading wall (55) being the first in contact with the first fluid (F1) during its passage at the level of the hollow protuberance (5). 9. Heat exchanger (1) according to claim 8, characterized in that the leading wall (55) of the hollow protuberance (5) and the channel (35) of the hollow element (31) form an angle ( a) between 0 ° and 90 ° (limits excluded), and in particular between 15 ° and 60 °. 10. Heat exchanger (1) according to any one of claims 8 or 9, characterized in that the end wall (57) of the protuberance (5) hollow and the channel (35) of the hollow element (31 ) form an angle (b) between 90 ° and 180 ° (limits excluded), and in particular between 105 ° and 150 °.