EP4004475A1

EP4004475A1 - Heat exchanger, in particular for a motor vehicle, and process for manufacturing such a heat exchanger

Info

Publication number: EP4004475A1
Application number: EP20754335.6A
Authority: EP
Inventors: Kamel Azzouz; Cédric DE VAULX; Mathieu Caparros; Xavier Marchadier
Original assignee: Valeo Systemes Thermiques SAS
Current assignee: Valeo Systemes Thermiques SAS
Priority date: 2019-07-25
Filing date: 2020-07-22
Publication date: 2022-06-01
Also published as: FR3099238A1; FR3099238B1; WO2021014091A1

Abstract

The invention relates to a heat exchanger comprising a heat exchange bundle (3) transferring heat between a first fluid (F1) and a second fluid (F2), said heat exchange bundle (3) being composed of: at least two hollow elements (31) that are designed to form a channel inside which the first fluid (F1) is intended to flow and to allow the second fluid (F2) to flow in a space (37) between the stacked hollow elements (31), wherein at least one of the hollow elements (31) has a plurality of protrusions (5) that are located at least on one of the first (33a) and/or second (33b) faces of the hollow element (31), said protrusions (5) extending into the space (37) defined for the second fluid (F2) to flow in; and the heat exchange bundle (3) comprises at least one additional fin (6) in the space (37) defined between two adjacent hollow elements (31).

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 a large number of motor vehicles. These heat exchangers can for example be dedicated to cooling motors or batteries, or to the operation of air conditioning devices.

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 circulating inside the hollow elements and a second coolant, such as air, circulating 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 this heat exchanger. However, the heat exchange bundle described in this document requires at least one comb in order to keep the various elements forming this heat exchange bundle together. The arrangement of this comb can be complex and the latter may be caused to move, in particular due to vibrations linked to the operation of the motor vehicle. Thus, the mechanical strength of this heat exchange bundle can be improved. On the other hand, the method of manufacturing the heat exchange bundle can be simplified.

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 each having a first and a second face, said hollow elements being configured to form a channel inside which the first fluid is intended to circulate and to allow circulation of the second fluid in a space between the superimposed hollow elements,

at least one of the hollow elements comprises a plurality of protrusions disposed at least on one of the first and / or second faces of the hollow element, said protuberances extending in the space defined for the circulation of the second fluid, and

the heat exchange bundle comprises at least one additional fin arranged in the space defined between two adjacent hollow elements, said additional fin cooperating with the protuberances. The presence of protuberances extending in the space for the circulation of the second fluid allows a disturbance of the second fluid during its passage through the heat exchanger, which allows an improvement in the homogenization of its temperature and therefore an improvement in its heat exchanges with the first fluid circulating inside the hollow elements. On the other hand, the presence of at least one additional fin also disposed in this space for the circulation of the second fluid also contributes to the disturbance of the circulation of this second fluid between two hollow elements of the heat exchange bundle. Thus, the combination of at least one additional fin and the protuberances contributes to the improvement of the heat exchanges between the first and second fluids within the 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 particular embodiment, the heat exchange bundle further comprises two end elements arranged parallel to the superimposed hollow elements and respectively on either side of the superposition of hollow elements. According to this particular embodiment, each end element has a face disposed opposite a first or a second face of the hollow element and defines a space between the end element and the hollow element for allow the circulation of the second fluid. The face of at least one end element disposed facing the first or the second face of the hollow element and / or the face of the hollow element disposed facing the end element comprises a plurality protuberances. In addition, the space defined between the end member and the hollow member for the passage of the second fluid has at least one additional fin.

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

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

According to one aspect, the superimposed hollow elements can be made of aluminum. Alternatively or in addition, the hollow elements can be made of a material having a thermal conductivity greater than or equal to 45 W.nrhK · ¹ at 20 ° C.

According to a first variant, the protuberances can be formed directly on the first and / or second faces of the at least one hollow element and / or on the face of at least one end element arranged opposite the hollow element. .

According to a second variant, the protuberances can be attached to the first and / or second faces of the at least one hollow element and / or to the face of at least one end element arranged opposite the hollow element.

According to a first particular embodiment, the protuberances may have a shape of constant cross section and a first end disposed in contact with the first face or the second face of the hollow element and a second free end, opposite the first end. , arranged in contact with the adjacent element.

According to this first particular embodiment, the cross section of the protuberance may be circular, oblong, or even parallelepiped.

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

According to this second particular embodiment, the protuberances may have a conical shape having a pointed or flat second free end, or a dome shape.

According to a first aspect, the second free ends of the protuberances carried by the first face of a first hollow element and by the second face of a second hollow element can be in contact with each other in the assembled state of the bundle d heat exchange. According to a second aspect, the second free ends of the protuberances carried by the first face or the second face of a hollow element can be in contact with a surface of an adjacent element of the heat exchange bundle in the assembled state of the bundle. heat exchange.

According to a third aspect, the second free ends of the protuberances carried by the first face of a first hollow element can alternatively be in contact with the second free ends of the protuberances carried by the second face of a second hollow element and with the second face of the second hollow element in the assembled state of the heat exchange bundle, the first face of the first hollow element being disposed opposite the second face of the second hollow element.

The second free end of the protuberances can be configured to provide the mechanical connection of the adjacent elements by brazing.

The at least one additional fin may extend throughout a length of the hollow members and / or the end members.

According to a variant, the at least one additional fin can have openings configured to cooperate with the protuberances carried by the first and / or the second face of the hollow element and / or the face of the end element arranged in sight of the hollow element.

According to a first particular embodiment, at least one additional fin can be planar.

According to a particular aspect, at least one additional fin may be solid and configured to be sandwiched between two protuberances carried by the faces of two adjacent elements arranged opposite one another.

According to one aspect of this first particular embodiment, the heat exchange bundle may comprise:

at least two additional flat fins arranged superimposed on each other in the space defined for the circulation of the second fluid, and

protuberances of variable cross section carried by at least one first and / or a second face of a hollow element and / or a face of an end element arranged opposite the hollow element,

at least one of the additional fins has the openings, and the openings have a section whose dimensions are adapted to the section of the protuberance of variable cross section so as to define the

positioning of the additional fin in the space for the passage of the second fluid of the heat exchange bundle.

The openings in the at least one additional fin may be circular in shape.

Alternatively or in addition according to this first particular embodiment, at least one additional fin may include at least one louver.

The at least one shutter can be arranged between the openings intended to cooperate with the protuberances carried by the first and / or the second face of the hollow element and / or of the face of the adjacent element arranged opposite the hollow element.

According to one aspect of this first particular embodiment, the at least one additional fin may further include at least one spacer extending parallel to the general direction of extension of the protuberances in space for the circulation of the second fluid.

The spacers can be configured to define an additional inter-fin space when the heat exchange bundle has more than one additional fin, the additional inter-fin space being intended to allow circulation of the second fluid.

The spacers can be configured to define a gap between the additional fin and the adjacent member to allow circulation of the second fluid between the additional fin and the adjacent member.

According to a second particular embodiment, the heat exchange bundle may comprise a single additional fin and the additional fin has at least one portion of sinusoidal shape, the curvature of which is arranged in the space defined for the circulation of the second fluid and between two consecutive protuberances in the direction of circulation of the first fluid in the hollow elements.

According to one aspect of this second particular embodiment, the faces of a hollow element and of an adjacent element arranged facing one another may have protuberances, and the additional fin of sinusoidal shape may have flat portions sandwiched between these protuberances.

As a variant or in addition, the additional fin of sinusoidal shape may have openings configured to cooperate with at least one protuberance carried by the first and / or second faces of the hollow element and / or the face of the element. end disposed opposite the hollow element so as to ensure the installation of this additional sinusoidal fin between two adjacent elements.

A subject of the present invention is also a method of manufacturing a heat exchanger as defined above. The manufacturing process includes the following steps:

making protrusions on at least a first and / or second face of at least one hollow element;

preparation of a stack comprising:

* at least two hollow elements, and

* at least one additional fin arranged between two adjacent hollow elements; and

heating and compression of the stack in order to allow brazing of the second free ends of the protuberances carried by the first and / or the second faces of the at least one hollow element with the adjacent hollow element arranged opposite these second free ends .

Such a manufacturing process is therefore simple to implement. In addition, the formation of a brazed mechanical connection between adjacent elements ensures good mechanical strength of the heat exchange bundle.

The method of manufacturing 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 one aspect, 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 disposed facing the first or the second face of a hollow element, the face of at least one of the end elements disposed facing the element hollow and / or the face of the hollow element arranged opposite the end element comprises a plurality of protuberances extending in a space defined for the circulation of the second fluid, the stack further comprising at least one fin additional disposed in this space defined between the hollow element and the adjacent end element for the passage of the second fluid.

According to a first particular embodiment, the protuberances can be produced directly on the first and / or second faces of the hollow element and / or on the face of at least one end element arranged opposite the hollow element. during the step of making the protuberances.

According to a second particular embodiment, the step of carrying out

protrusions may comprise a first sub-step of forming protuberances on a strip distinct from the hollow element and / or from the end element and a second sub-step of positioning this strip having the protuberances on the first and / or the end element. or second faces of the hollow element and / or on the face respectively of the end element disposed opposite the hollow element; said strip being sandwiched between at least one additional fin and the hollow member and / or the end member.

According to a first aspect, the protuberances can be produced by deformation of a surface of the first and / or second faces of the hollow element and / or of the face respectively of at least one end element arranged opposite the hollow element, or the strip, and in particular by stamping, during the step of producing the protuberances.

According to a second aspect, the protuberances can be produced by depositing material on a surface of the first and / or second faces of the hollow element and / or of the face respectively of at least one end element placed opposite the elements. hollow or strip during the protuberance production step. According to a first variant of this second aspect, the step of producing protuberances can be carried out by a cold metallization process on the first and / or second faces of the hollow elements and / or on the face of at least one element d. end disposed opposite the hollow element or on the strip.

The cold metallization process can involve the use of a mask.

According to a particular embodiment of this first variant, the cold metallization process can implement a first sub-step of spraying particles composed of a first material followed by a second sub-step of spraying a second material, different from the first material, on the face of the element having the protuberances or on the strip.

The cold metallization process can use a gas at a pressure which may be between 5 bars and 50 bars and at a temperature which may be less than or equal to 1100 ° C.

The gas used in the cold metallization process can be chosen from argon, helium, hydrogen, alone or as a mixture.

According to a second variant, the step of producing protuberances can be carried out by a direct metal deposition process on the first and / or second faces of the hollow element and / or on the face respectively of at least one element of end disposed opposite the hollow element or on the strip.

The direct metal deposition process uses a laser whose power can be between 0.3 kW and 4 kW.

According to a particular embodiment, the manufacturing method may further comprise a step of making openings intended to cooperate with the protuberances carried by the first and / or the second face of the hollow element and / or the face

respectively of at least one end element arranged opposite the hollow element in the at least one additional fin, said step of making openings being carried out upstream of the step of preparing the stack. Alternatively or in addition, the manufacturing process may further comprise a step of producing at least one louver in the at least one additional louver, this step of producing at least one louver being carried out upstream of the louver. step of preparing the stack.

According to a particular embodiment, the step of making at least one louver can be carried out simultaneously with the step of making openings in at least one additional fin.

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 strip having protrusions;

[Fig. 3B] Figure 3B is an exploded schematic perspective view of a heat exchange bundle with protrusions attached to hollow elements of the heat exchanger of Figure 1;

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

[Fig. 4B] FIG. 4B is a schematic perspective representation of a set of protuberances according to a second variant;

[Fig. 4C] FIG. 4C is a schematic perspective representation of a set of protrusions according to a third variant; [Fig. 5A] FIG. 5A is a schematic perspective representation of a set of protuberances according to a fourth variant;

[Fig. 5B] FIG. 5B is a schematic perspective representation of a set of protrusions according to a fifth variant;

[Fig. 5C] FIG. 5C is a schematic representation of a set of protuberances according to a sixth variant;

[Fig. 6] Figure 6 is a schematic front view of the heat exchange bundle of the heat exchanger of Figure 1 according to a first particular embodiment;

[Fig. 7A] FIG. 7A is a schematic front view of a portion of an additional fin according to a first alternative;

[Fig. 7B] Figure 7B is a schematic front view of the portion of the additional fin of Figure 7A according to a variant;

[Fig. 8A] FIG. 8A is a schematic front view of a heat exchange bundle of the heat exchanger of FIG. 1 according to a variant of the first particular embodiment;

[Fig. 8B] FIG. 8B is a schematic front view of a heat exchange bundle of the heat exchanger of FIG. 1 according to another variant of the first particular embodiment;

[Fig. 9A] FIG. 9A is a schematic front view of a portion of an additional fin according to a second alternative;

[Fig. 9B] Figure 9B is a schematic front view of the portion of the additional fin of Figure 9A according to a variant;

[Fig. 10A] FIG. 10A is a schematic front view of a heat exchange bundle of the heat exchanger of FIG. 1 according to a second particular embodiment; [Fig. 10B] FIG. 10B is a schematic front view of a heat exchange bundle of the heat exchanger of FIG. 1 according to a variant of the second particular embodiment;

[Fig. 10C] FIG. 10C is a schematic front view of a heat exchange bundle of the heat exchanger of FIG. 1 according to another variant of the second particular embodiment;

[Fig. 11A] FIG. 11A is a schematic front view of a portion of an additional fin according to a third alternative;

[Fig. 11B] Figure 11B is a schematic front view of a portion of the additional fin of Figure 11A according to a variant;

[Fig. 12A] FIG. 12A is a schematic front view of a portion of an additional fin according to a fourth alternative;

[Fig. 12B] FIG. 12B is a schematic front view of a portion of the additional fin of FIG. 12A according to a variant;

[Fig. 13] Figure 13 is a schematic front view of a heat exchange bundle of the heat exchanger of Figure 1 according to a third particular embodiment; and

[Fig. 14] Figure 14 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 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 which are similar but not identical. This indexing does not imply a priority of an element, parameter or criterion with respect to another and it is easily possible to interchange such names without departing from the scope of the present description. This indexation does not imply an order in time, for example, to assess such and such criteria.

In the following description, the term “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.nrhK- ¹ ).

On the other hand, the term “surface” is understood in the following description to mean an extent representing at least a portion of the first or of the second face of the hollow element, of the face of the first or of the second end element arranged. facing the hollow elements, or the strip.

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 composed of at least two hollow elements 31 superimposed. Each hollow element 31 forms a 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 and the second manifold 13 has for example an outlet 13a in order to supply the hollow elements 31 with the first fluid F1. This first heat transfer fluid F1 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 for the first fluid F1 can be attached to the heat exchange bundle 3 by brazing or by a mechanical connection, in particular by crimping, for example. The hollow elements 31 superimposed on 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 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 F1 and the second F2 fluids in this heat exchange bundle 3 in order in particular to allow heat exchanges of the first fluid F1.

The hollow elements 31 each have a first 33a and a second 33b faces (visible in FIG. 2). These hollow elements are also configured to allow the circulation of the second fluid F2 in a space 37 (better visible in FIG. 2) between the hollow elements 31 in order to allow heat exchange between the first F1 and the second F2 fluids during the operation of this heat exchanger 1. The second heat transfer fluid 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 by example. According to a first variant, the hollow elements 31 of the heat exchange bundle 3 can be plates in order to form a plate heat exchanger 1. According to a first variant, the hollow elements 31 of the heat exchange bundle 3 can be flat tubes in order to form a tube heat exchanger 1.

Referring to Figures 1 and 2, at least one hollow element 31 comprises a plurality of protuberances 5 arranged on at least one of the first 33a and / or second 33b face of the hollow element 31. The protuberances 5 extend into 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. According to a first particular embodiment, the protuberances 5 can be carried by the first face 33a of a first hollow element 31a arranged opposite the second face 33b of a second hollow element 31b. The second face 33b of the second hollow element 31b has no protuberance 5. In such a case, the space 37 then comprises protuberances 5 coming from a single hollow element 31.

According to a variant and as shown with reference to FIG. 2, the protuberances 5 can be carried by the first 33a and second 33b faces of each hollow element 31 constituting the heat exchange bundle 3. The space 37 then comprises protuberances 5 coming from two adjacent hollow elements 31.

On the other hand, the protuberances 5 provide a mechanical connection by brazing with the adjacent hollow element 31 having a face disposed opposite the protuberances 5 carried by the at least one hollow element 31. The term adjacent element is understood here to mean an element. of the heat exchange bundle 3 arranged opposite a first 33a or a second 33b face of a hollow element 31. The assembly of the heat exchange bundle 3 by brazing makes it possible to ensure good mechanical retention of this heat exchange bundle 3. Moreover, it is the protuberances 5 which define the space 37 for the passage of the second fluid F2. In the case of heat exchangers of the prior art, this space was provided by the presence of fins arranged between the hollow elements 31 and substantially

perpendicular to these hollow elements 31. The presence of the protrusions 5 therefore makes it possible to limit the number of constituents of the heat exchange bundle 3, which in particular makes it possible to simplify its structure and its assembly. Such a heat exchange bundle 3 therefore has fairly low production costs while ensuring good mechanical strength thereof.

According to the particular embodiment of FIG. 1, the heat exchange bundle 3 can further include two end elements 38, 39. The end elements 38, 39 of the heat exchange bundle 3 are arranged parallel to the ends. hollow elements 31 superimposed and respectively on either side of the superposition of hollow elements 31. These end elements 38, 39 have a face disposed facing a first 33a or a second 33b face of a hollow element 31. These end elements 38, 39 may in particular define a space 37 'between the end element 38, 39 and the adjacent hollow element 31 to allow the circulation of the second fluid F2. Thus, the second fluid F2 is intended to pass at the level of the first 33a and second 33b faces of each hollow element 31. These end elements 38, 39 can be produced by a plate, for example of metal, of a metal alloy, such as for example of aluminum or of an alloy of 'aluminum. According to one variant, the material constituting the end elements 38, 39 is identical to that forming the hollow elements 31.

On the other hand, the face of this at least one end element 38, 39 disposed opposite the first 33a or the second 33b face of the hollow element 31 may include a plurality of protuberances. Thus, and as before, the protuberances extend into the space 37 ’for the circulation of the second fluid F2 between the hollow member 31 and the adjacent end member 38, 39.

In addition, the space 37 'defined for the passage of the second fluid F2 between the hollow element 31 and the adjacent end element 38, 39 may include at least one additional fin 6 (visible for example in FIG. 6) . As before, this additional fin also contributes to the disturbance of the circulation of the second fluid F2 in this space 37 'and therefore allows in particular a better homogenization of the temperature of the second fluid F2 and therefore an improvement of the heat exchanges between the first F1 and second F2 fluids within this heat exchange bundle 3.

According to a first aspect, one, the other or both end elements 38, 39 may have protuberances arranged on the face of these end elements 38, 39 arranged respectively facing the first 33a or the second 33b face of a hollow element 31.

According to this first aspect, the first 33a or second 33b faces of the hollow elements 31 arranged opposite the end elements 38, 39 may be planar, that is to say not have any protuberance. In this case, only the protrusions 5 carried by the at least one end member 38, 39 extend into the space 37 ’. In the case where only one or the other of the end elements 38, 39 has the protuberances, then the end element 38, 39 not having any protuberances can be placed in contact with the hollow element 31 adjacent.

According to a variant of this first aspect and as shown with reference to FIG. 2, the first 33a and second 33b faces of the hollow elements 31 arranged facing the end elements 38, 39 have protrusions 5. In this case, the protuberances 5 carried by the different elements 31, 38, 39 forming the heat exchange bundle 3 extend in the space 37, 37 'defined for the passage of the second fluid F2 on either side of the first 33a and second 33b faces of the hollow elements 31 of the heat exchange bundle 3.

According to a second aspect, the faces of the end elements 38, 39 arranged opposite the first 33a or the second 33b face of the adjacent hollow element 31 are smooth, that is to say they do not have no protrusions, and the first 33a and second 33b faces of the hollow elements 31 have protrusions 5 (as shown with reference to Figure 2) in order to ensure the formation of the space 37, 37 'for the circulation of the second fluid F2 in the assembled state of the heat exchange bundle 3.

Furthermore, the protuberances 5 carried by the face of the hollow element 31 or by the end element 38, 39 provide a mechanical connection by brazing with the face of the adjacent element 31, 38, 39 arranged opposite the protrusions 5. By adjacent element 31, 38, 39 is meant an element arranged facing a first 33a or a second 33b face of a hollow element 31. An adjacent element can therefore be another hollow element 31 or one of the end elements 38, 39.

According to the particular embodiment of FIG. 2, the protuberances 5 are formed directly on the first 33a and / or second 33b faces of the hollow element 31. According to the variant in which the heat exchange bundle 3 has the elements d 'ends 38, 39 (visible in figure 1), the protuberances can also be formed

directly on the face of the end elements 38, 39 arranged opposite the hollow elements 31. According to this particular embodiment, the protuberances 5 can be produced by deformation of a surface of the first 33a and / or second 33b faces of the elements hollow 31 and / or of the face of the end elements 38, 39 disposed opposite the hollow elements 31. Alternatively, these protuberances 5 can be formed by adding material to this surface as will be described in more detail later.

According to an alternative shown with reference to FIGS. 3A and 3B, the protuberances 5 may be attached to the first 33a and second 33b faces of the hollow elements 31 or to at least one end element 38, 39 intended to present protuberances 5 when 'they are here. The protuberances 5 can in particular be formed on a strip 7, shown in FIG. 3A. This strip 7 is distinct from the hollow elements 31 or else from the end elements 38, 39. This strip 7 is then placed opposite the first 33a and / or second 33b faces of the hollow element 31, for example, as shown. with reference to FIG. 3B, or of the face of at least one end element 38, 39 intended to include protuberances. The representation of FIG. 3B is an exploded view of the strip 7 and of the hollow elements 31, but this exploded view is only presented to clearly distinguish the strip 7 from the hollow elements 31. The fixing of this strip 7 on the surface of the elements 31, 38, 39 may be produced by brazing during a step of brazing the heat exchange bundle 3, for example as described in more detail

later. On the other hand, the strip 7 can be made of the same material as the hollow elements 31. The strip 7 can in particular be made of metal or a metal alloy, such as for example aluminum or an aluminum alloy. Furthermore, the protuberances 5 can be formed on the strip 7 by deformation of the surface of this strip 7 or even by adding material to this strip 7.

With reference to FIGS. 4A to 4C, examples of protuberances 5 according to a first variant are shown. According to this first variant, the protuberances 5 may have a shape of constant cross section. By constant cross-sectional shape, it is understood here that the protuberance 5 has a diameter (in the case of a cylindrical protuberance) or a constant cross-section over the whole of its height h, 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 protuberances 5 have a first end 51 disposed in contact with the face of the element 31, 38, 39 which carries the protuberance 5 and a second free end 53, opposite the first end 51, in contact with the hollow element 31. or the adjacent end member 38, 39. According to the various embodiments shown with reference to FIGS. 4A to 4C, there is shown two protuberances 5, the second free ends 53 of which are respectively arranged in contact with one another. Such an arrangement of the protuberances 5 can offer significant resistance to the deformations associated with the passage of the second fluid F2 in the space 37, 37 '. More particularly according to this first variant, the cross section of the protuberance 5 may be oblong (FIG. 4A), parallelepiped (FIG. 4B), or even circular (FIG. 4C). With reference to FIGS. 5A to 5C, examples of protuberances according to a second variant are shown. According to this second variant, the protuberances 5 may have a shape of variable cross section. The expression variable cross-sectional shape is understood here to mean that the protuberance 5 has a diameter or a cross-section

transverse variable over the whole of its height h, 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 s 'extends. In such a case, the protuberances 5 have a first end 51 disposed in contact with the face of the element 31, 38, 39 which carries the protuberance 5 and a second free end 53, opposite the first end 51, in contact with the hollow member 31 or the adjacent end member 38, 39. The first end 51 has an area greater than that of the second free end 53. According to the various embodiments shown with reference to FIGS. 5A to 5C, there is shown two protuberances 5, the second free ends 53 of which are respectively arranged in contact with one another. other. Such protuberances 5 can make it possible to limit the pressure drop and 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 at the same time disrupting the circulation of this second fluid F2 in space 37, 37 '. More particularly according to this second variant, the protuberances 5 may have a conical shape having a second free end 53 pointed (FIG. 5A), flat (FIG. 5B), or even a dome shape (FIG. 5C).

With reference to FIGS. 4A to 5C, the shape of the protuberances 5 can 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 exchange bundle. thermal 3. The shape of these protuberances 5 can also be chosen according to the disturbances of the flow of the second fluid F2 desired in the space 37, 37 '(visible in particular in FIG. 1) ·

According to different variants not shown here, the second free ends 53 of the protuberances 5 carried by the faces of the two adjacent elements 31, 38, 39 arranged opposite one another can cooperate in different ways in the assembled state of the bundle. heat exchange 3. According to a first variant, the second free ends 53 of the protuberances 5 carried by the faces of two adjacent elements 31, 38, 39 arranged opposite one another can be in contact with one another.

According to a second variant, the second free ends 53 of the protuberances 5 carried by a face of an element 31, 38, 39 may be in contact with a surface of an adjacent element 31, 38, 39. More particularly, the second free ends 53 of the protuberances 5 carried by the first face 33a of the first hollow element 31a are in contact with the second face 33b of the second hollow element 31b and vice versa. Such cooperation is also conceivable for the cooperation of the second ends 53 of the protuberances 5 carried by a face of a hollow element 31 arranged opposite the end element 38, 39 (visible in FIG. 1) adjacent in the case of where the face of this end element 38, 39 is smooth.

According to a third variant, the second free ends 53 of the protuberances 5 carried by the first face 33a of the first hollow element 31a can be in contact alternately with the second free ends 53 of the protuberances 5 carried by the adjacent element 31, 38, 39. and with the face of the adjacent element 31, 38, 39 disposed opposite the first face 33a of the first hollow element 31a. More particularly, the adjacent element may correspond to a second hollow element 31b, the second face 33b of which has protrusions 5 configured to have their second ends 53 disposed in contact with certain protuberances 5 carried by the first face 33a of the first hollow element 31a and zones devoid of protuberances configured to be in contact with the second end 53 of protuberances 5 having a size equal to a height of the space 37 defined for the circulation of the second fluid F2 between the first 31a and second 31b hollow elements. Such a configuration of the protuberances 5 can make it possible to modify the disturbances of the second fluid F2 during its flow through the heat exchange bundle 3, and also to play on the speed of movement of this second fluid F2 inside it. space 37, 37 'during its passage through the heat exchange bundle 3.

On the other hand, and with reference to FIG. 6, the heat exchange bundle 3 comprises at least one additional fin 6 (better shown with reference to FIGS. 7A to 9B) in this case five additional fins 6a - 6c. These additional fins 6a, 6b, 6c are arranged in the space 37 defined for the passage of the second fluid F2 between two adjacent hollow elements 31. These additional fins 6a, 6b, 6c are arranged

parallel to the hollow elements 31. These additional fins 6a, 6b, 6c also contribute to the disturbance of the flow of the second fluid F2 in the space 37. Thus, these additional fins 6a, 6b, 6c ensure a homogenization of the temperature of the second fluid F2 improved compared to the heat exchange beams known from the prior art. As a result, these additional fins 6a, 6b, 6c contribute to the improvement of heat exchanges between the first Fl and second F2 fluids within this heat exchange bundle 3 and therefore within the heat exchanger 1 ( visible in figure 1). On the other hand, these additional fins 6a, 6b, 6c cooperate with the protuberances 5.

Such an additional fin 6, 6a, 6b, 6c is for example shown with reference to Figures 7A and 7B. This additional fin 6, 6a, 6b, 6c can for example be made of metal, and in particular of a material having a thermal conductivity greater than or equal to 45 W.nrhK- ¹ . According to a particular aspect, the material constituting the at least one additional fin 6, 6a, 6b, 6c is identical to that forming the hollow elements 31 (visible for example in FIG. 2), in order in particular to allow fixing of the 'fin

6, 6a, 6b, 6c by brazing with the protuberances 5. Fixing by brazing the additional fin 6, 6a, 6b, 6c on the protuberances 5 also contributes to

improving heat exchange between the first F1 and second F2 fluids within the heat exchange bundle 3 by preventing the formation of a thermal bridge between the protuberances 5 and the additional fin 6, 6a, 6b, 6c. According to these different embodiments, the additional fin 6, 6a, 6b, 6c is flat.

According to the particular embodiment of FIG. 7A, the additional fin 6, 6a is solid and corresponds to a plate intended to be placed in the space 37, 37 'for the circulation of the second fluid F2 between two elements 31, 38 , 39 adjacent. Such an additional fin 6, 6a can in particular be configured to be sandwiched between two protuberances 5 carried respectively by the faces of two adjacent elements 31, 38, 39 arranged opposite one another. Such an additional fin 6, 6a can in particular be brazed between these two protuberances 5 in order to allow the formation of the heat exchange bundle 3. According to the embodiment of FIG. 7B, the additional fin 6, 6b, 6c may have openings 61. These openings 61 are configured to cooperate with the protuberances 5 carried by at least one element 31, 38, 39 of the beam of heat exchange. To this end, the openings 61 have a section s, the dimensions of which are adapted to the dimensions of the protuberance 5 with which this opening 61 is intended to cooperate. Such openings 61 allow in particular an arrangement of the additional fin 6, 6b, 6c at different places in the space 37, 37 'defined for the circulation of the second fluid F2, as well when the protuberances 5 are carried by a single element. 31, 38, 39 of the heat exchange bundle 3 than by two adjacent elements 31, 38, 39 whose faces presenting the protuberances 5 are arranged opposite one another. In addition, such openings 61 can cooperate equally well with protrusions 5 of constant cross section (as shown with reference to Figures 4A to 4C) or of variable cross section (as shown with reference to Figures 5A to 5C). In addition, the edge of these openings is intended to be brazed on the outer surface of the protuberances 5 in order to allow this additional fin 6, 6b, 6c to be held in position in the heat exchange bundle 3. According to the embodiment Particularly of FIG. 7B, the openings 61 are circular in shape. Such shapes are easy to obtain and their section s can easily be modified as well. According to other variants not shown, other shapes for the openings 61 can be envisaged, such as for example substantially parallelepipedal or even triangular shapes, these other shapes being adapted to the shape of the cross section of the protuberances 5.

According to the particular embodiment of Figure 6, the protuberances 5 carried by the hollow elements 31 are of variable cross section and the heat exchange bundle 3 has five additional fins 6a, 6b, 6c arranged in the space 37 for the passage of the second fluid F2. According to other variants described later, other

configurations of the heat exchange bundle 3 can be envisaged. According to the particular embodiment of FIG. 6, the heat exchange bundle 3 has a first additional fin 6a, arranged in the center of the space 37 for the circulation of the second fluid F2, two second additional fins 6b arranged opposite the first additional fin 6a, and two third additional fins 6c arranged between the face 33a, 33b of the hollow element 31 and the second additional fin 6b. According to this particular embodiment, the first additional fin 6a does not have openings 61 and corresponds therefore to the additional fin 6a shown with reference to FIG. 7A, and the second 6b and third 6c additional fins have at least the openings 61 and therefore correspond to the additional fin 6b, 6c shown with reference to Figure 7B. These first 6a, second 6b and third 6c additional fins are arranged superimposed with respect to each other in the space 37 defined for the circulation of the second fluid F2. In addition, in order to allow the positioning of the second 6b and third 6c additional fins, the section s of the openings 61 present in these additional fins 6b, 6c is not constant. More particularly the section s of the openings 61 of the third additional fins 6c has larger dimensions than the section s of the openings 61 of the second additional fins 6b. Thus, the positioning of the second 6b and third 6c additional fins is determined by the dimensions of the section s of the openings 61 present in these second 6b and third 6c additional fins. More particularly according to the embodiment of FIG. 6, the protuberances 5 are of conical shape with a pointed second free end 53 as shown with reference to FIG. 5A. In order to allow their insertion and their positioning on these protuberances 5, the second 6b and third 6c additional fins have openings 61 of circular shape. With such cooperation of the additional fins 6 with the protuberances 5 it is possible to adapt their positioning in the space 37 by adapting the diameter of the openings 61 to the external diameter of the protuberance 5 of conical shape. Such

positioning can also be envisaged in the space 37 'defined between a hollow element 31 and an end element 38, 39, the protuberances 5 being able to be carried by a face 33a, 33b of the hollow element 31 or even by the face one, the other, or each end element 38, 39.

Referring to Figures 8A and 8B, there are shown variants of the first particular embodiment of the heat exchange bundle 3 described above with reference to Figure 6.

According to the particular embodiment of FIG. 8A, the protuberances 5 of the heat exchange bundle 3 have a section of variable shape (shown with reference to FIGS. 5A to 5C). More particularly, these protuberances are carried respectively by the first face 33a of a first hollow element 31a and by the second face 33b of a second hollow element arranged opposite the first face 33a of the first hollow element 31a. On the other hand, the heat exchange bundle 3 has a single fin additional 6 sandwiched between the second free ends 53 of the protuberances 5. This additional fin 6 may for example correspond to the additional fin 6 shown with reference to FIG. 7A.

Referring to Figures 9A and 9B, there is shown the additional fin 6 according to a variant. According to this variant, the additional fin 6 may have at least one spacer 65 extending parallel to the general direction of extension of the protuberances 5 in the space 37, 37 'for the circulation of the second fluid F2, as is by example best seen in Figure 8B. More particularly, these spacers 65 are arranged

perpendicular to the direction of flow of the second fluid F2 within the heat exchange bundle 3. This spacer 65 can also contribute to the disruption of the flow of the second fluid F2 within the heat exchange bundle 3 so

to improve the heat exchanges between the first F1 and second F2 fluids within this heat exchange bundle 3.

According to the particular embodiment of FIG. 9A, the additional fin 6 has spacers 65 arranged peripherally and perpendicularly to the general direction of circulation of the second fluid F2 inside the space 37. According to others variants not shown here, the spacers 65 may have a different arrangement on an additional fin 6.

On the other hand, according to the particular embodiment of FIG. 9B, the fin

additional 6 further presents the openings 61 intended to cooperate with

protrusions 5. According to this particular embodiment, the spacers 65 are offset with respect to the openings 61 on the additional fin 6. Such an arrangement of the spacers 65 makes it possible in particular to improve the disturbances in the circulation of the second fluid F2 at the level of its entry into the heat exchange bundle 3. In addition, the arrangement of the spacers 65 on either side of the additional fin 6 makes it possible to facilitate its

positioning in the heat exchange bundle 3.

According to the particular embodiment of FIG. 8B, there is shown another variant of the first particular embodiment. More particularly, the first 6a, second 6b and third 6c additional fins each have spacers 65. These spacers 65 have a dual role. On the one hand, these spacers allow define a space between these various additional fins 6a, 6b, 6c, and on the other hand they also play a role of disturbing the circulation of the second fluid F2. According to this particular embodiment, the spacers 65 all extend in the same direction and can be carried only by certain additional fins 6a, 6b, 6c. More particularly, one of the third additional fins 6c does not have any spacers 65 and may correspond for example to the additional fin 6c shown with reference to FIG. 7B while the other additional fins 6 of the heat exchange bundle 3 all have spacers 65 and may correspond to the additional fins 6 shown with reference to Figures 9A and 9B.

According to other variants of this first particular embodiment not

shown here, the protuberances 5 may be of variable cross section and carried only by the first 33a or the second 33b face of the hollow element 31, or alternatively by at least one of the end elements 38, 39 when they are present . In such a case, the additional fin 6 has the openings 61 (shown with reference to FIGS. 7B, 9B) intended to cooperate with the protuberances 5. In addition, the openings 61 have a section s whose dimensions are configured to allow the positioning of this additional fin 6 in the heat exchange bundle 3, this positioning being dependent on the dimensions of the cross section of the protuberance 5 of variable cross section.

Referring to Figures 10A to 10C, there is shown different variants of a second embodiment of the heat exchange bundle 3. According to these different variants of the second embodiment, the protuberances 5 are of constant cross section and can therefore correspond. the protrusions described with reference to Figures 4A to 4C.

According to the embodiment of FIG. 10A, the heat exchange bundle 3 has a first hollow element 31a having protuberances 5 on its first face 33a. On the other hand, the second face 33b of the second hollow element 31b, disposed opposite the first face 33a of the first hollow element 31a, is smooth, that is to say that it does not have any protuberances 5. According to this first variant, the space 37 defined for the passage of the second fluid F2 has a single additional fin 6. According to this particular embodiment, the additional fin 6 has at least the openings 61 configured to cooperate with the protuberances 5 carried by the first face 33a of the first hollow element 31a, and in particular the insertion of the protuberances 5 into the openings 61 of the additional fin 6 in order to allow its positioning in the space 37 defined for the circulation of the second fluid F2. The additional fin 6 therefore corresponds to the additional fin 6 described with reference to FIG. 7B for example. More particularly according to this particular embodiment, the protuberance 5 has a cylindrical shape (as shown in FIG. 4C) and the additional fin 6 has an opening 61 whose section s has a diameter such as the outer wall of the protuberance 5. is in contact with the inside of the opening 61 in the engaged state of the additional fin 6 on the

protrusion 5 to allow attachment by brazing of the additional fin 6 on the protrusion 5.

According to the particular embodiment shown with reference to FIG. 10B, the heat exchange bundle 3 has protuberances 5 carried by only one face of the elements 31, 38, 39 forming this heat exchange bundle 3 as described previously with reference in Figure 10A. This heat exchange bundle 3 has a single additional fin 6 arranged in the space 37, 37 ’defined for the circulation of the second fluid F2. This additional fin 6 has spacers 65 oriented on either side of this additional fin 6. The ends of these spacers 65 are in contact with the adjacent elements 31, 38, 39. Thus, these spacers 65 define a distance between the different adjacent elements 31, 38, 39 forming this heat exchange bundle 3. In addition, these additional fins 6 have the openings 61 configured to cooperate with the protuberances 5 carried by the different elements. 31, 38, 39 of this heat exchange bundle 3. These additional fins 6 therefore correspond to the additional fin 6 described with reference to FIG. 9B.

According to the particular embodiment of Figure 10C, the heat exchange bundle 3 has protuberances 5 carried by the first 33a and second 33b faces of the first 31a and second 31b hollow elements. These protrusions 5 are also protrusions 5 having a constant cross section, and in particular of cylindrical shape as shown with reference to FIG. 4C. According to this particular embodiment, the heat exchange bundle 3 has three additional fins 6a, 6b superimposed in the space 37 defined for the circulation of the second fluid F2. More

in particular, the heat exchange bundle 3 has a first fin additional 6a intended to be sandwiched between the second free ends 53 of the protuberances 5 carried by the first 33a and second 33b faces of the first 31a and second 31b hollow elements. Thus, this first additional fin 6a is solid and may correspond to those described with reference to FIGS. 7A or 9A. On the other hand, the heat exchange bundle 3 has two second additional fins 6b arranged respectively between the first additional fin 6a and the first 31a or the second 31b hollow element. In order to allow their positioning in the heat exchange bundle 3, these second additional fins 6b have the openings 61

configured to cooperate with the protuberances 5 (as shown with reference to Figures 7B, 9B). According to this particular embodiment, the second additional fins 6b have spacers 65 in order to allow their positioning relative to each other in the heat exchange bundle 3. Thus, these spacers 65 define an additional inter-fin space b in order to allow the circulation of the second fluid F2 in the space 37, 37 '. In addition, and still according to this particular embodiment, the spacers 65 also define a distance between at least one of the second additional fins 6b and the adjacent element 31, 38, 39, and more particularly the second hollow element 31b. This spacing is also configured to allow the circulation of the second fluid F2 between this second additional fin 6b and the second hollow element 31b.

Referring to Figures 11A to 12B, there is shown other variations of the additional fin 6.

According to the embodiments shown with reference to FIGS. 11A and 11B, the additional fin 6 may also have at least one louver 63. This at least one louver 63 corresponds to a device for disturbing the flow of the second fluid F2. Thus, this louver 63 also contributes to improving the homogenization of the temperature of the second fluid F2 during its circulation through the heat exchange bundle 3. This louver 63 therefore contributes to improving the heat exchanges between the first F1 and second F2 fluids within this heat exchange bundle 3. More particularly according to the embodiments shown with reference to FIGS. 11A and 11B, the louvers 63 are arranged so as to have an extension arranged perpendicular to the direction general flow of the second fluid F2 through the heat exchange bundle 3 (visible in particular in FIG. 6). In addition, these FIGS. 11A, 11B, only a portion of the additional fin 6 is shown.

According to the particular embodiment of FIG. 11A, the portion of the additional fin 6 has three rows of louvers 63. Such an additional fin 6 is intended to be sandwiched between two protuberances 5 carried respectively by the faces of two elements. 31, 38, 39 adjacent arranged opposite one another as has been previously described.

On the other hand, according to the particular embodiment of FIG. 11B, the additional fin 6 comprises, in addition to the louvers 63, the openings 61 intended to cooperate with the protuberances 5 carried by at least one face of an element 31, 38 , 39 of the heat exchange bundle 3. According to this particular embodiment, the louvers 63 are arranged in rows and these rows are arranged between the openings 61. Furthermore, according to this particular embodiment, each space defined between two openings 61 intended to cooperate with protuberances 5 on the additional fin 6 has a row of louvers 63. According to other variants not shown here, the rows of louvers 63 may have different arrangements depending on the desired disturbance of the circulation of the second fluid. F2.

In addition, with reference to FIGS. 11A and 11B, the additional fin 6 may have the rows of louvers 63 as shown over the entire length of the heat exchange bundle 3. Alternatively, the additional fin 6 may have louvers 63 randomly over the length of the heat exchange bundle 3. For example, according to the embodiment of FIG. 11B, the additional fin 6 may have a row of louvers 63 between two openings 61 and then be full between the next two openings 61 and so on along the length of the heat exchange bundle 3.

Furthermore, according to the particular embodiments, described with reference to FIGS. 12A and 12B, the additional fin 6 may have, in addition to the louvers 63, the spacers 65. These additional fins 6 shown with reference to FIGS. 12A and 12B have the same. characteristics than those described previously with reference to Figures 9A and 9B. According to a third particular embodiment shown with reference to FIG. 13, the heat exchange bundle 3 has a single additional fin 6. This additional fin 6 has at least one portion of sinusoidal shape. This portion of sinusoidal shape has a curvature 67 disposed in the space 37, 37 'defined for the circulation of the second fluid F2 and between two consecutive protuberances 5 in the direction of circulation of the first fluid F1. Such a sinusoidal shape for the fin additional 6 also makes it possible to disturb the circulation of the second fluid F2 as it passes through the heat exchange bundle.

According to the particular embodiment of Figure 13, the elements 31, 38, 39 of the heat exchange bundle 3 each have protrusions 5 having second free ends 53 arranged facing each other. On the other hand, this additional fin 6 has flat portions 69 arranged at the level of the protuberances 5. According to this particular embodiment, the flat portions 69 of the additional fin 6 are solid and sandwiched between the second free ends 53. of

protuberances 5 carried by two adjacent elements 31, 38, 39 arranged facing each other.

According to an alternative not shown here, the protuberances 5 can be carried only by one face of an element 31, 38, 39 of the heat exchange bundle 3. In order to allow its installation, the flat portion 69 of the additional fin 6 of sinusoidal shape may have the openings 61 in order to allow its installation and its positioning between two adjacent elements 31, 38, 39 of the heat exchange bundle 3.

Referring to Figure 14, there is shown a manufacturing process 100 of a heat exchanger 1 as described above. The manufacturing process 100 comprises a step of producing E1 protuberances 5 on at least one face of at least one hollow element 31. These protuberances 5 can be produced directly on the hollow element 31 or be produced upstream on the strip 7. (visible in Figures 3A and 3B).

When the protuberances 5 are produced directly on the hollow element 31, they can be produced by deformation, and in particular by stamping, of a surface of the first 33a and / or second 33b face of the hollow element 31. Such a face preparation of the protuberances 5 is quick to implement and also allows the first fluid F1 to pass inside these protuberances 5, which makes it possible to improve the heat exchanges between the first Fl and second F2 fluids when they pass through the heat exchange bundle 3.

According to an alternative, the protuberances 5 can be made on the hollow element 31 by adding material to a surface of the first 33a and / or second 33b faces of the hollow element 31. Such additions of material can for example be made by a cold metallization process, or even by a direct metal deposition process, on this surface and in particular on the first 33a and / or second 33b faces of the hollow elements 31. Such embodiments of the protuberances by additive processes make it possible to for example have access to complex shapes for these protuberances which would only be difficult to access by a stamping process, or else to give the protuberances 5 thus produced particular properties.

The cold metallization process can implement the use of a mask in order to be able to define sections of particular shapes for these protuberances. The cold metallization process corresponds to the projection of a material on the surface in order to allow the formation of protuberances 5. The cold metallization process uses a gas under a pressure which may be between 5 bars and 50 bars and at a temperature which may be less than or equal to 1100 ° C. The projection temperature of the material must be lower than the melting point of this material in order to avoid any crystalline modification or even any oxidation thereof. Furthermore, the use of pressurized gas makes it possible to give a sufficient speed to this material so that it undergoes a plastic deformation at the time of its impact on the hollow element 31 and forms the protuberance 5 by accumulation of material linked to this. plastic deformation. The gas used for this cold metallization process can for example be chosen from argon, helium and dihydrogen, alone or as a mixture. According to a particular embodiment, the cold metallization process can implement a first sub-step of spraying particles composed of a first material followed by a second sub-step of spraying a second material, different from first material, on the surface of the hollow elements 31. According to this aspect, the second material may have brazing properties superior to those of the first material in order to facilitate a subsequent step of this manufacturing process 100. Furthermore, the first and second materials intended to form the protuberances 5 must have sufficient chemical compatibility to ensure the mechanical retention of the beam heat exchange 3. It is thus possible to modify certain physicochemical properties of the protuberances 5.

As for the direct metal deposition process, it uses a laser whose power can be between 0.3 kW and 4 kW. In fact, the direct metal deposition process corresponds to the projection of a powder on the surface of the desired hollow element 31 and then to the irradiation of this powder with the aid of the laser in order to allow the latter to melt. This direct metal deposition process makes it possible to produce protuberances 5 on the first 33a and / or the second 33b faces of the hollow element 31 having small thicknesses, and in particular being able to reach thicknesses of the order of 0.2 mm.

According to a variant, the protuberances 5 can be produced on the strip 7 (shown with reference to FIGS. 3A and 3B) distinct from the hollow elements 31. For this, the production step E1 of the protuberances 5 comprises a first formation sub-step protuberances on the strip 7 then a second sub-step of

positioning of this strip 7 having the protuberances 5 on the first 33a and / or second 33b faces of the hollow elements 31. The various techniques for forming the protuberances 5 described above, as well as regards the deformation of a surface of the strip 7 that as regards the deposit of material on the surface of the strip 7 in order to form the protuberances 5, can also be used during the first sub-step of forming the protuberances 5 on the strip 7. Moreover, the second sub-step of positioning this strip 7 corresponds to the arrangement of this strip 7 facing the first 33a and / or second 33b faces of the hollow element 31. This strip 7 is therefore placed opposite the face of the element hollow 31 intended to present the

protrusions 5.

The manufacturing process 100 then implements a step of preparing a stack E2. This stack comprises at least two hollow elements 31, at least one of which has at least one face comprising the protuberances 5, and at least one additional fin 6 disposed between two hollow elements 31. In addition, when the protuberances 5 have been produced on the strip 7, this stack further comprises the strip 7 disposed between a hollow element 31 and at least one additional fin 6. According to a variant, the stack may further comprise two end elements 38, 39. These end elements 38, 39 are arranged on either side of the superposition of hollow elements 31 and parallel to these hollow elements. 31. These end elements 38, 39 respectively have a face arranged opposite a first 33a or a second 33b face of a hollow element 31. On the other hand, at least one of the elements

ends 38, 39 may include a plurality of protuberances 5 on its face disposed opposite the first 33a or the second 33b face of the hollow element 31. On the other hand, these protuberances 5 can be produced directly on the end element 38, 39 by deformation of a surface of this end element 38, 39 or by depositing material on this surface as described above. Alternatively, the

protrusions 5 can be attached to the end element 38, 39 with the strip 7 described above. These protuberances 5 extend into the space 37 ’defined for the circulation of the second fluid F2. Furthermore, the stack may further include at least one additional fin 6 disposed in this space 37 ’defined between the hollow element 31 and the adjacent end element 38, 39.

The manufacturing process 100 then implements a heating step and

compression E3 of the stack in order to allow brazing of the second free ends 53 of the protuberances 5 with the adjacent hollow element 31 disposed opposite these second free ends 53 and of at least one additional fin 6 with the protuberances 5 in order to ensure the cooperation of this additional fin 6 with the protuberances 5 in the assembled state of the heat exchange bundle 3. Thus, the manufacturing process 100 is simple and quick to implement, in particular due to the reduction in constituent elements of the heat exchange bundle 3 of the heat exchanger 1. In addition, the strip 7 having the protuberances 5, when it is present, is brazed to the faces of the hollow elements 31 having it during this step of heating and compression E3. In addition, when the heat exchange bundle 3 presents the end elements 38, 39, these end elements 38, 39 are brazed with the hollow elements 31 during this heating and compression step E3.

The manufacturing method 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. According to a particular embodiment, the method 100 may further comprise a step of producing (not shown) openings 61 intended to cooperate with the protuberances 5 carried by the first 33a and / or second 33b faces of the hollow element 31. and / or the face respectively of at least one end element 38, 39 arranged opposite the hollow element 31 in at least one additional fin 6. This step of making openings 61 is carried out upstream of the step of preparing the stack E2.

Alternatively or in addition, the manufacturing process 100 can comprise a step of producing (not shown) at least one louver 63 in at least one additional fin 6. This step of producing at least one louver 63 is also carried out upstream of the step of preparing the stack E2. According to a particular embodiment in which the additional fin 6 has openings 61 and louvers 63, the steps for producing openings 61 and louvers 63 can be carried out simultaneously, which makes it possible, among other things, to limit the manufacturing times of such a heat exchange bundle 3 and facilitate the positioning of the louvers 63 between the openings 61 of the additional fin 6.

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 protrusions 5 than those described previously, such as for example cross sections of triangular shape or even protrusions 5 of pyramidal shape. , without departing from the scope of the present description. On the other hand, those skilled in the art will be able to use other deposition methods to form the

protuberances by depositing material on the surface of the elements 31, 38, 39 or of the strip 7 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 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 the joining of the various adjacent hollow elements 31 of the heat exchange bundle 3 and allows an increase in the heat exchange surface improving the exchanges between the first F1 and second F2 fluids. On the other hand, the joining of the various hollow elements 31 adjacent to this heat exchange bundle 3 by brazing at the level of the protuberances 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 of the heat exchanger 1. In addition, the presence of at least one additional fin 6 also allows an improvement in the heat exchanges between the first F1 and second F2 fluids thanks to the increase in the disturbance of the circulation of the second fluid F2 to through the heat exchange bundle 3.

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 each having a first (33a) and a second (33b) faces, said hollow elements (31) being configured to 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 hollow elements (31) superimposed,

characterized in that

at least one of the hollow elements (31) comprises a plurality of protuberances (5) arranged at least on one of the first (33a) and / or second (33b) faces of the hollow element (31), said protrusions (5) s 'extending into the space (37) defined for the circulation of the second fluid (F2), and in that

the heat exchange bundle (3) comprises at least one additional fin (6) arranged in the space (37) defined between two adjacent hollow elements (31), said additional fin (6) cooperating with the protuberances (5).

2. Heat exchanger (1) according to the preceding claim, characterized in that the heat exchange bundle (3) further comprises 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 first (33a) or a second (33b) face of the hollow element (31) and defining a space (37 ') between the end element (38, 39) and the hollow element (31) to allow the circulation of the second fluid (F2), in that the face of at least one end element (38, 39) disposed opposite the first (33a) or the second (33b) face of the hollow element (31) and / or the face (33a, 33b) of the hollow element (31) disposed opposite the end element (38, 39) comprises a plurality of protuberances (5), and in that the space (37 ') defined between the element of end (38, 39) and the hollow element ( 31) for the passage of the second fluid (F2) comprises at least one additional fin (6).

3. Heat exchanger (1) according to claims 1 or 2, characterized in that the at least one additional fin (6) has openings (61) configured to cooperate with the protuberances (5) carried by the first (33a). ) and / or the second face (33b) of the hollow element and / or the face of the end element (38, 39) arranged opposite the hollow element (31).

4. Heat exchanger (1) according to any one of claims 1 to 3, characterized in that at least one additional fin (6) is planar.

5. Heat exchanger (1) according to claim 4, characterized in that the

heat exchange bundle (3) comprises:

at least two additional plane fins (6) arranged superimposed with respect to each other in the space (37, 37 ’) defined for the circulation of the second fluid (F2), and

protuberances (5) of variable cross section carried by at least a first (33a) and / or a second (33b) face of a hollow element (31) and / or a face of an end element (38, 39) arranged opposite the hollow element

(31),

in that at least one of the additional fins (6) has the openings (61), and

in that the openings (61) have a section (s) whose dimensions are adapted to the cross section of the protuberance (5) of variable cross section so as to define the positioning of the additional fin (6) in the space (37, 37 ') for the passage of the second fluid (F2) of the heat exchange bundle (3).

6. Heat exchanger (1) according to any one of claims 3 to 5, characterized in that at least one additional fin (6) comprises at least one louver (63).

7. Heat exchanger (1) according to any one of claims 3 to 6, characterized in that the at least one additional fin (6) further comprises at least one spacer (65) extending parallel to the direction. general extension of the protuberances (5) in the space (37) for the circulation of the second fluid (F2).

8. Heat exchanger (1) according to claim 1 or 3, characterized in that the heat exchange bundle (3) comprises a single additional fin (6) and in that the additional fin (6) has at least a portion of sinusoidal shape whose curvature (67) is disposed in the space (37, 37 ') defined for the circulation of the second fluid (F2) and between two consecutive protuberances (5) in the direction of circulation of the first fluid ( Fl) in the hollow elements (31).

9. Heat exchanger (1) according to claim 8, characterized in that the faces of a hollow element (31) and of an adjacent element (31, 38, 39) arranged opposite one another have protuberances (5), and in that the additional sinusoidal fin (6) has flat portions (69) sandwiched between these protuberances (5).

10. Manufacturing process (100) of a heat exchanger (1) according to a

any of the preceding claims, characterized in that it comprises the following steps:

production (El) of protuberances (5) on at least a first (33a) and / or second (33b) face of at least one hollow element (31);

preparation of a stack (E2) comprising:

* at least two hollow elements (31), and

* at least one additional fin (6) disposed between two adjacent hollow elements (31); and

heating and compression (E3) of the stack in order to allow brazing of the second free ends (53) of the protuberances (5) carried by the first (33a) and / or the second (33b) faces of the at least one element hollow (31) with the adjacent hollow element (31) disposed opposite these second free ends (53).