Heat exchangers interact with a loop for circulation of heat transfer fluid or of cold transfer fluid in order to generate an exchange of calories between air outside the vehicle, directed to pass through these heat exchangers, and the heat transfer fluid or the coolant fluid.

Such heat exchangers may be radiators, condensers or, alternatively, supercharger air coolers in which a plurality of tubes are stacked upon one another with inserts arranged between them. The fluid of the loop circulates inside the tubes and exchanges calories with the exterior air traversing the inserts of the heat exchanger.

Conventionally, such heat exchangers are arranged at the front end of motor vehicles in order to optimize the capture of exterior air upstream of the engine that is arranged in the engine compartment of the vehicle.

The position of such heat exchangers at the front end exposes the forwardmost heat exchanger of the vehicle to the kicking-up of debris or chippings that might damage or even pierce the tubes inside which the heat transfer fluid or the coolant fluid circulates. More precisely, the tubes of the forwardmost heat exchanger of the vehicle are arranged transversely relative to the direction of movement of the vehicle, in a flat, horizontal arrangement. As a result, the tubes of this forwardmost heat exchanger of the vehicle are exposed to chippings and kicked-up detritus on their edge that faces the front of the vehicle.

With a view to protecting these heat exchangers, it is known to place facing them a protective grille that can hold back chippings or any other projectile and thus prevent impacts on the tubes of the exchangers. It is, for example, known from document FR3035956 to arrange a protective grille upstream of the one or more heat exchangers of the motor vehicle, clipping this grille onto the heat exchanger.

Although an arrangement of this type allows appropriate protection of the heat exchangers, it should nevertheless be noted that the presence of the grille gives rise, on the one hand, to an increase in the space required longitudinally, which is a problem in this zone where available space is limited. Furthermore, although the protection afforded by a protective grille of this type improves the situation, it is nevertheless not entirely satisfactory because the impact that results from the strike of a chipping may cause the grille to break.

Thus, the intention herein is to improve the mechanical behaviour of the tubes of the heat exchanger that are at risk of being struck by chippings or other projectiles.

The subject matter of the invention is a heat exchange device comprising at least one heat exchanger comprising a plurality of tubes configured for the circulation of a fluid, said tubes being spaced apart from one another in order to delimit a passage for a stream of air, said heat exchanger being delimited by an entry face via which the stream of air is able to enter the heath exchanger. The heat exchange device further comprises at least one protective net arranged along the entry face, the heat exchange device comprising means of attachment of said protective net to said heat exchanger.

The protective net is arranged along the entry face, upstream of the entry face relative to the direction of circulation of the stream of air. In other words, the stream of air traverses the protective net prior to penetrating the heat exchanger. In this configuration, chippings or any other projectile reach the protective net rather than the heat exchanger.

The protective net is arranged along the entry face, i.e. facing all or part of the entry face. Advantageously, the protective net is arranged along the entirety of the entry face, i.e. it fully covers the entry face. A heat exchange device according to the invention may comprise any onest of the following features taken alone or in combination:

- The heat exchange device comprises at least three means of attachment of the protective net to the heat exchanger. Arranged thus, the attachment means allow tensioning of the protective net facing the entry face.

- The protective net is manufactured from a material that makes it possible to obtain elastic properties at the macroscopic scale. As a result, the protective net is able to deform elastically upon impact with chippings, debris or any other projectile before resuming its initial position. This effect enables the protective net to provide protection for one or more consecutive impacts without deformation of its structure that could detract from the protection of the heat exchanger or the flow of the stream of air through the heat exchange device.

- The protective net is manufactured from fabric or from a thermoplastic material. More particularly, the protective net is manufactured from at least one natural fibre, at least one synthetic fibre or a mixture of at least one natural fibre and at least one synthetic fibre. The natural fibres that may be used for the manufacture of the protective net comprise, without being limited thereto, cotton, hemp, linen, Manila fibre and sisal. The synthetic fibres that can be used for the manufacture of the protective net comprise, without being limited thereto, polyamide, polypropylene, polyester, polyvinyl alcohol, polyethylene, copolymers and composite threads.

- The protective net comprises an exterior periphery and an interior mesh.

- The exterior periphery comprises a thread of a first type and the interior mesh comprises a thread of a second type. The first type of thread differs from the second type of thread in terms of at least one parameter, such as the diameter of the thread, the size of the fibres and/or the component material. Other parameters may also vary between the first type of thread and the second type of thread. The interior mesh of the protective net extends at a distance from the tubes. In other words, the interior mesh of the protective net is arranged relative to the tubes with a transverse offset, the transverse direction corresponding to the direction of passage of air through the heat exchanger. The transverse offset is measured between a first plane, in which the protective net extends, and a second plane, in which the transverse end of the tubes that is closest to the entry face extends, in a direction perpendicular to the first plane. The transverse offset has a dimension greater than the maximum elastic deformation of the interior mesh in this transverse direction. The transverse offset is between 5 and 50 millimetres.

The attachment means define a zone of contact with the protective net, the zones of contact extending in a plane set back relative to the plane in which the entry face extends. This feature allows optimum tensioning of the net facing the entry face of the heat exchanger.

At least one insert is arranged in at least one passage between the tubes and is configured to allow the stream of air to pass. Advantageously, an insert is arranged in each passage between the tubes.

The dimension of the inserts in the direction of flow of the stream of air, i.e. in the transverse direction, is greater than the dimension of the tubes in this same direction. The difference between the dimension of the inserts and that of the tubes in the direction of flow of the stream of air is greater than the maximum elastic deformation of the interior mesh in this same direction. The difference is between 5 and 50 millimetres. At least a part of the protective net is in contact with at least one insert. More particularly, the protective net is in contact with one transverse end of at least one insert, the transverse end in question being the transverse end of the insert that is closest to the entry face.

The protective net is attached by four attachment means in such a manner as to be stretched facing the entirety of the entry face of the heat exchanger. The four attachment means are each arranged at a corner of the heat exchanger. More particularly, the attachment means are each arranged at a corner of the entry face of the heat exchanger. In this arrangement, the protective net covers the entirety of the entry face of the heat exchanger.

- The attachment means are inserted in at least one end wall of the heat exchanger and/or at least one manifold and/or at least one water receptacle.

A further aspect of the invention relates to a motor vehicle comprising, at the front end, a heat exchange device as described above, the heat exchange device being arranged such that the protective net is oriented towards the front of the vehicle relative to the heat exchanger. In this aspect of the invention, it will be understood that the fact that the protective net is oriented towards the front of the vehicle means that this net is upstream in the direction of circulation of the stream of air relative to the heat exchanger and thus in position to be the first to receive the impact of chippings.

Other features and advantages of the invention will become further apparent from the following description, on the one hand, and from a number of illustrative embodiments given by way of non-limiting indication, with reference to the appended schematic drawings, on the other, in which:

- Figure 1 is a schematic, expanded representation of a heat exchanger showing two manifolds and a stack of tubes between which inserts are arranged, the figure further illustrating, by means of an arrow, the direction of the stream of air caused to traverse the heat exchanger;

- Figure 2 is an expanded representation of a heat exchange device comprising, in particular, a heat exchanger and a protective net;

- Figure 3 illustrates one embodiment of a protective net according to the invention;

- Figure 4 is a schematic representation of the heat device according to one embodiment of the invention, seen in cross section in a vertical transverse plane, illustrating the arrangement of the protective net along the entry face of the heat exchanger. in the remainder of the description, the terms "longitudinal", "vertical" or "transverse" relate to the orientation of the heat exchanger according to the invention. The longitudinal direction corresponds to the principal direction of the heat exchanger in which its greatest dimension extends, and particularly in the principal direction of the tubes making up this exchanger. The vertical direction corresponds to the direction of stacking of the tubes constituting the heat exchanger, the transverse direction being the direction corresponding to the direction of circulation of the stream of air through the heat exchanger. The longitudinal, transverse and vertical directions are likewise visible in a trihedron L, V, T shown in the figures.

The terms "upstream" and "downstream" are used to describe the arrangement of a component relative to the direction of circulation of a particular fluid.

Naturally, the features, variants and different embodiments of the invention may be associated with one another, in various combinations, in so far as they are not incompatible with one another or do not exclude one another. It will in particular be possible to envisage variants of the invention that comprise only a selection of features described below in isolation from the other features described, if such a selection of features is sufficient to confer a technical advantage or to differentiate the invention from the prior art.

Figure 1 shows a heat exchanger 2 according to the invention that is a component of a fluid circuit, for example a coolant fluid circuit, which equips a vehicle, in particular a motor vehicle. This heat exchanger 2 implements an exchange of calories between two fluids and, in particular, between the fluid circulating in the circuit and a stream of air.

The heat exchanger comprises a plurality of tubes 4 arranged parallel to one another, while being superposed in a stacking direction 6, each tube delimiting one or more conduits in which the fluid is able to circulate. The tubes 4 are stacked between a first end wall 20 and a second end wall 22, which are opposite one another in the vertical direction of stacking of the tubes 4.

The space between two tubes 4 according to the invention delimits a passage 10 where a stream of air is able to circulate with a view to exchanging calories with the fluid circulating in the tubes 4. In order to enhance the thermal exchanges between the fluid and the stream of air, inserts 8 are arranged in the space where the stream of air circulates. These inserts 8 serve to increase the surface of contact with the stream of air in order to optimize the heat exchanges between fluid and stream of air. The inserts 8 are in the form of fins, although it will be understood that other forms of inserts 8 may be used without compromising the spirit of the invention.

All the tubes 4 according to the invention are connected, at one longitudinal end, to a first manifold 12 and, at the other longitudinal end, to a second manifold 14. The first manifold 12 is arranged in order to distribute the fluid entering the heat exchanger 2 into the various tubes 4 constituting said heat exchanger 2. The second manifold 14 is arranged in order to collect the fluid that has traversed the tubes 4 in order to cause it to exit the heat exchanger 2.

The heat exchanger 2 has two principal faces extending in longitudinal and vertical planes, one of the two being identified as an entry face 5, through which the stream of air is able to enter the heat exchanger 2. More particularly, when the heat exchanger 2 is mounted in the front compartment of a motor vehicle, the heat exchanger 2 is arranged such that the principal faces are perpendicular to the direction of forward movement of the vehicle and thus to the direction of flow 3 of the stream of air, and the entry face 5 is oriented towards the exterior at the front of the vehicle. The entry face 5 is thus the face of the heat exchanger 2 that is the first to be in contact with the stream of air in the direction of flow 3 illustrated schematically by an arrow in Figure 1 .

Figure 2 shows a heat exchange device 1 according to the invention. The heat exchange device 1 comprises a heat exchanger 2 on which a protective net 30 is arranged.

The protective net 30 is arranged facing the entry face 5 of the heat exchanger 2. In this configuration, the stream of air traverses the protective net 30 prior to traversing the heat exchanger 2.

In the example illustrated, the protective net 30 extends over the entire entry face 5, i.e. the protective net 30 covers the entry face 5 between the first manifold 12 and the second manifold 14 on the one hand and between the first end wall 20 and the second end wall 22 on the other. The protective net 30 thus covers the entirety of the tubes 4. Similarly, the protective net 30 covers the entirety of the inserts 8.

The heat exchanger 2 further comprises means for connecting these manifolds to a fluid circuit that is part of a thermal loop of the motor vehicle. Each manifold is connected to a sleeve. The first manifold 12 is thus connected to a first sleeve 16 via which the fluid is able to enter the heat exchanger 2, the second manifold 14 being connected to a second sleeve 18 via which the fluid is able to exit the heat exchanger 2.

Means 40 of attachment of the protective net 30 are provided to fasten and tension the protective net 30 facing the entry face 5 of the heat exchanger 2. The attachment means 40 are positioned in threading 50 provided in a structural element defining the periphery of the heat exchanger 2, in this case a manifold 12, 14. Alternatively, threading 50 may be provided in an end wall 20, 22 of the heat exchanger 2. The attachment means 40 described here are screws.

In the example illustrated here, a part of the attachment means 40, in particular a screw head 54, pinches a part of the exterior periphery 32 against the structural element of the heat exchanger 2 comprising the threading 50, ensuring retention of the protective net 30.

Each attachment means 40 defines a zone 48 of contact with the exterior periphery 32 of the protective net 30, in this case by contact of the net with the screw head 54, this screw head forming a stop to the transverse disengagement of the protective net once said protective net is in position. According to one feature of the invention, the attachment means 40 and the protective net are configured such that the zones 48 of contact defined previously extend in a plane forming a setback 52 relative to the plane of extension of the forwardmost members of the heat exchanger that play a part in defining the entry face 5. This feature allows optimum tensioning of the protective net 30 facing the entry face 5 of the heat exchanger 2, the exterior periphery 32 of the protective net being drawn rearwards whilst the interior mesh 34 is held back against the members of the heat exchanger, in this case the inserts, as will be described by way of example in connection with Figure 4.

The attachment means 40 are securely connected to the structural elements of the heat exchanger, such as the manifolds or the end walls, by screwing in the embodiment illustrated, in which these attachment means are screws that may, as will be described below, be inserted by screwing to a greater or lesser depth in the threading. This embodiment makes it possible to adjust the tensioning of the protective net, but without departing from the context of the invention there could be fixed attachment means secured to the structural elements by gluing, brazing, riveting, snap-riveting, welding or any other appropriate method, around which attachment means the protective net is attached. Other attachment means 40 can be envisaged, in particular spikes, snap-fit means, or any other appropriate attachment means. In a variant of the invention, the screws forming the attachment means 40 may comprise a notch arranged on the screw stem and dimensioned in order to receive the thread of a protective net meshwork in order to facilitate retention of this protective net.

Figure 3 shows the protective net 30 that constitutes the invention. The protective net 30, of rectangular shape, comprises an exterior periphery 32 and an interior mesh 34. The interior mesh 34 comprises a plurality of criss-crossed threads forming meshwork 36 and attached to the exterior periphery 32.

The meshwork 36 is of a size to allow the retention of the majority of chippings, debris and projectiles without overly disrupting the flow of the stream ot air through the interior mesh 34.

The exterior periphery 32 comprises at least one thread of a first type. The term "thread" here denotes both a single thread and a strand composed of a plurality of threads. The interior mesh 34 comprises at least one thread of a second type.

Having a first type of thread that is different from the second type of thread makes it possible to confer different properties on each part of the protective net 30. By way of example, it is thus possible on the one hand to increase the stiffness of the exterior periphery 32 in order to facilitate the interaction with the attachment means 40 for installation and holding of the protective net 30 on the heat exchanger 2 and, on the other hand, to increase the capacity of the interior mesh 34 to deform and to withstand impacts upon contact of chippings.

This functional difference can be achieved by means of a choice of particular materials, and these may, in particular, be natural fibres such as cotton, hemp, flax, Manila fibre or sisal, synthetic fibres such as polyamide, polypropylene, polyester, polyvinyl alcohol, polyethylene, copolymers or composite threads, or a mixture of synthetic fibres and natural fibres. In particular, the first type of thread is a thread manufactured from hemp or from flax. The second type of thread is a thread composed of cotton.

This functional difference may also be achieved by means of the two types of thread having different sizes, with, as illustrated in Figure 3, a diameter of the thread of first type, involved in forming the exterior periphery 32, being greater than the diameter of the thread of second type involved in forming the interior mesh 34, it being possible for the exterior periphery 32 to form a rigid frame.

The nature and manufacture of the protective net 30 gives it elastic properties. These elastic properties are characterized by a limited capacity of the protective net 30 to deform such that the interior mesh 34 never enters into contact with the tubes 4 of the heat exchanger 2. Figure 4 shows an example of the positioning of the protective net 30 on the heat exchanger 2 and, in particular, the fastening of the protective net 30.

The protective net 30 is tensioned by means of the cooperation of the exterior periphery 32 and the attachment means 40. This tensioning at the attachment means 40 thus has the effect of being reproduced on the interior mesh 34 of the protective net 30, which is thus tensioned and substantially planar.

In this example of arrangement of the heat exchange device 1 , the inserts 8 have a dimension greater than that of the tubes 4 considered in the direction 3 of flow of the stream of air.

Since the tubes 4 and the two end walls 20, 22, or the two manifolds 12, 14, depending on the structural element of the heat exchanger 2 on which the attachment means 40 are installed, have an identical dimension, considered in the direction 3 of flow of the stream of air, the protective neck 30 is thus in contact with the transverse ends 44 of the inserts 8 that are closest to the entry face 5. The transverse ends 44 of the inserts 8 correspond to the faces of the inserts 8 that are the first in contact with the stream of air as it flows.

Thus, a transverse offset 46 is present between the protective net 30 and the tubes 4. The transverse offset 46 is measured between a first plane of extension of the protective net 30 and a second plane of extension of a transverse end 42 of the tubes 4 that is closest to the entry face 5, in a direction perpendicular to the first plane. The transverse ends 42 of the tubes 4 correspond to the faces of the tubes 4 that are the first in contact with the stream of air as it flows. The transverse offset is between 10 and 50 millimetres.

In this configuration, chippings, debris or any other projectile reaching the protective net 30 between the transverse ends 44 of two adjacent inserts 8 will be slowed down and deflected by the protective net 30 without reaching or damaging the tube 4 between the two adjacent inserts 8. In this same configuration, the impact of chippings, debris or any other projectile reaching the protective net 30 in contact with a transverse end 44 will be reduced by the thickness of the internal mesh 34 and damage to the insert 8 will be reduced.

In a variant of the invention, the tubes 4 and the inserts 8 have an identical dimension, considered in the direction 3 of flow of the stream of air. In this variant, the two end walls 20, 22 or the two manifolds 12, 14, depending on the structural element of the heat exchanger 2 on which the attachment means 40 are installed, have a dimension greater than that of the tubes 4 and of the inserts 8 considered in the direction 3 of flow of the stream of air, such that, as previously, a transverse offset 46 is present between the protective net 30 and the tubes 4. The transverse offset is between 5 and 50 millimetres.

In this configuration, chippings, debris or any other projectile reaching the protective net 30 between the first end wall 20 and the second end wall 22 will be slowed down and deflected by the protective net 30 without reaching or damaging any of the tubes 4.

A description will now be given of a method for manufacturing and mounting a heat exchange device according to the invention, with reference, in particular, to the embodiment of the attachment means as just described.

The tubes 4 and the inserts 8 of the heat exchanger 2 are manufactured from a sheet of a material that is designed to permit sufficient heat exchanges in order to allow the heat exchanger 2 to fulfil its role. It may, in particular, be aluminium or an aluminium alloy. The tubes 4 and inserts 8 are, respectively, pressed, stamped or rolled from a metal sheet.

The tubes 4 are then stacked, alternating with the inserts 8, between the first end wall 20 and the second end wall 22. The heat exchanger 2 can then be mounted by connecting the tubes 4 to the first manifold 12, to the second manifold 14, to the first sleeve 16 and to the second sleeve 18, and then connected to a fluid circuit. At this stage, and according to the illustrative embodiment of mounting that is described, the screws forming attachment means 40 are inserted into the bores 50 and screwed in such a manner as to assume a first, pre-assembly position.

The protective net 30 is then arranged facing the entry face 5 of the heat exchanger 2 and the operator successively passes the exterior periphery 32 of the protective net 30 around each of the attachment means 40, pulling on the net where appropriate in order to be able to achieve this attachment. The net is thus tensioned overall in a plane parallel to the entry face of the heat exchanger.

It will be understood that it would be possible to reach this intermediate position by, in a first step, positioning an attachment means 40 and attaching an edge of the net around it and then by successively screwing the other attachment means with the protective net already engaged around the corresponding screw.

Once the protective net has been tensioned parallel to the entry face, the screws forming attachment means are screwed into the corresponding bores 50 such that the zone 48 of contact formed between the screw head 54 and the exterior periphery 32 of the protective net 30 draws closer to the structural element in which the bore is made. The exterior periphery 32 continues to move towards the structural elements forming the frame of the heat exchanger until it is pinched between these structural elements and the attachment means 40, whilst the interior mesh 34 remains immobilized in contact with the front end of the forwardmost members of the entry face, in this case the front end of the inserts 8. The setback between the exterior periphery 32 and the interior mesh 34 of the protective net 30 thus plays a part in tensioning the net in the transverse direction, i.e. the direction of movement of the stream of air through the heat exchanger.

As explained above, other manufacturing methods may be employed. In particular, the tube 4 according to the invention may be manufactured by using an additive manufacturing method. The heat exchanger 2 thus set up is capable of functioning in accordance with the following example. This example is non-limiting, and other methods of functioning may be envisaged.

The fluid circulates within the tubes 4 involved in forming the heat exchanger 2. More particularly, the fluid enters the first manifold 12 via the first sleeve 16, the first sleeve 18 being connected to the fluid circuit outside the heat exchanger 2. From the first manifold 12, the fluid is distributed and circulates within the various tubes 4 of the invention. After its circulation along the tubes 4, the fluid is collected in the second manifold 14 and then conveyed to the exterior circuit via the second sleeve 18.

Furthermore, a stream of air circulates in the space 10 left between two successive tubes 4 of the heat exchanger 2. in the course of its circulation within these tubes 4, the fluid will exchange calories with the stream of air via the walls of the tube 4 and the inserts 8 arranged in the space 10 between the tubes 4, i.e. it will heat up or cool down the walls of the tube 4 and the inserts depending on the difference in temperature between the fluid and the air.

Thus, in an example of the functioning of the heat exchanger 2 set up to cool the fluid circulating in the heat exchanger 2, the fluid circulating within the tubes 4 will transfer calories to the walls of the tube 4 and then to the inserts 8 arranged in contact with the walls of the tube 4. The stream of air, in contact with the inserts 8, will absorb the heat diffused by the inserts 8, thereby raising its temperature.

It will be understood that the heat exchanger 2 of the invention may likewise be set up in order to cool the stream of air, the fluid circulating in the heat exchanger 2 then being cooler than the stream of air. The fluid will then absorb the calories from the stream of air traversing the space 10 between the tubes 4, thereby lowering the temperature of the stream of air.

The above description clearly explains how the invention makes it possible to achieve the objectives set by it and, in particular, to propose a heat exchange device comprising a protective net arranged on an entry face of a heat exchanger in order to protect the latter from kicked-up chippings or any other projectile.

Naturally, diverse modifications may be made by a person skilled in the art to the heat exchange device just described by way of non-limiting example provided a flexible protective net protecting a face of a heat exchanger is implemented.

In any event, the invention cannot be limited to the embodiments specifically described in this document and extends, in particular, to all equivalent means and to any technically effective combination of these means.