The various aspects of the present invention concern the field of heat exchangers and in particular the protection of the heat exchangers placed on the front panel of a motor vehicle.

Heat exchangers interact with a fluid circulation loop in order to generate an exchange of calories between the fluid and air from outside the vehicle directed so as to pass through these heat exchangers.

In these heat exchangers, a plurality of tubes are stacked on one another with spacers arranged between them. The fluid circulates inside the tubes and exchanges calories with the air from outside that passes through the spacers of the heat exchanger.

These heat exchangers are conventionally arranged on the front panel of the motor vehicles for optimum capture of the air from the outside and on the upstream side of the engine that for its part is disposed in the engine compartment of the vehicle.

The position of these heat exchangers on the front panel exposes the heat exchanger of the vehicle closest to the front to the projection of debris or gravel that can damage or even perforate the tubes inside which the fluid circulates. The side facing toward the front of the vehicle of the tubes of this heat exchanger situated closest to the front of the vehicle are exposed to the gravel and projections.

In order to protect these heat exchangers, it is known to place in front of them a protection grille that can retain the gravel, or any other projectile, and therefore prevent impacts on the tubes of the exchangers. It is known from the document FR3035956 for example to dispose a protection grille on the upstream side of the heat exchanger or exchangers of the motor vehicle by clipping that grille onto the heat exchanger. The protection provided by this grille improves the situation but is nevertheless not totally satisfactory because the shock following the impact of a gravel stone can cause the grille to break.

Accordingly, one aim is to improve the strength of the tubes of the heat exchanger that are at risk of being struck by gravel or other projectiles.

One aspect of the invention consists in a device for protecting a heat exchanger, the heat exchanger comprising a bundle of tubes able to have a first fluid pass through them and delimited by an inlet face and by an outlet face, the inlet face being configured so that a second fluid passes through the bundle of tubes and exchanges calories with the first fluid, the protection device comprising a series of longitudinal elements for protecting the tubes configured to be disposed facing the inlet face and a frame carrying the series of longitudinal protection elements and configured to connect the protection device to the heat exchanger, recognisable in that the frame is made of a first material whilst the series of longitudinal protection elements is made of a second material more flexible than the first material.

The modulus of elasticity of the first material is between 2300 and 16000 MPa inclusive and the modulus of elasticity of the second material is between 1 .5 and 100 MPa inclusive. It is clear here that the first material is more rigid and harder than the second material, so that the frame forms a structural support of the protection device, whilst the series of longitudinal protection elements forms shock-absorbing means.

It will be noted that the series of longitudinal protection elements is configured so that at least one longitudinal element of the series covers at least partially a side of a tube of the bundle. Thus the longitudinal elements are rectilinear, or substantially rectilinear, and are disposed relative to one another with a pitch identical or similar to the pitch of the tubes of the heat exchanger.

The first material is advantageously a polypropylene or a polyamide, in particular charged with glass fibres, carbon fibres or natural fibres. The second material is an elastomer thermoplastic or a natural rubber. It can equally well be an elastomer of ethylene-propylene-diene monomer type. The second material is generally speaking any material capable of damping and resisting a shock generated by a projectile projected against the longitudinal element at a speed of sixty kilometres/hour.

In accordance with one embodiment, the frame comprises at least one upright fastened to a plurality of longitudinal protection elements, the upright being configured to be arranged facing the inlet face of the heat exchanger. The upright then forms a mechanical support for a plurality of longitudinal elements, which extends transversely, for example perpendicularly, to the direction in which the longitudinal elements extend. An upright of this kind extends along the inlet face of the heat exchanger and crosses the second fluid that enters the heat exchanger via this inlet face.

Instead of or in addition to the above, the frame may comprise a surround that peripherally surrounds the series of longitudinal protection elements. In accordance with one example, the frame is therefore constituted exclusively of the surround. In accordance with another example, the frame comprises the surround and the uprights as described above.

The invention is also directed to a heat exchanger device including a heat exchanger comprising a bundle of tubes able to have a first fluid pass through them and are delimited by an inlet face and by an outlet face, the inlet face being configured to have pass through it a second fluid that exchanges calories with the first fluid, and a protection device as described in the present document fastened to the heat exchanger. In such a situation, the longitudinal elements of the series of longitudinal protection elements are disposed in front of the sides of the tubes of the bundle of the heat exchanger so as to protect those sides against an impact caused by a projectile.

The invention finally covers a motor vehicle including on the front panel a heat exchanger device as described in the present document characterized in that the heat exchanger device is configured so that the protection device is oriented toward the front of the vehicle.

Other features and advantages of the invention will become more apparent from the following description of one embodiment given by way of nonlimiting illustration with reference to the appended drawings, in which:

- Figure 1 is a front perspective view of a protection device in accordance with the present invention;

- Figure 2 is a front perspective view of a heat exchanger device in accordance with the invention; and

- Figure 3 is a view in section taken along the line l-l shown in Figure 2.

A first subject matter of the invention is a protection device 1 the function of which is to protect a heat exchanger against impacts of projectiles liable to pierce a tube of the heat exchanger. Assembled to one another, this heat exchanger and this protection device 1 form a second subject matter of the invention in the form of a heat exchanger device, as shown in Figure 2 or in Figure 3.

In Figure 1 , the protection device 1 has the general shape of a grille intended to be placed in front of a heat exchanger, with reference to the direction of circulation of a flow of air that passes through the heat exchanger.

The protection device 1 comprises at least one series or plurality of longitudinal protection elements 2, of which only some carry reference numbers in Figure 1 , to prevent overcomplicating the figure. The protection device 1 also comprises at least one frame 3 the function of which is to impart mechanical strength to the plurality of longitudinal protection elements 2. In other words, this frame 3 is a member carrying the series of longitudinal protection elements 2. The longitudinal elements 2 are parallel, or substantially parallel, to one another. As a function of the disposition of the heat exchanger on the vehicle, the longitudinal elements 2 may be aligned horizontally or vertically. Whatever the orientation of the heat exchanger, this series of longitudinal protection elements 2 lies in a plane A visible in Figure 1 , this plane having pass through it the flow of air intended to pass through the heat exchanger.

These longitudinal elements 2 form absorption zones capable of absorbing a vibratory wave following the impact of a gravel stone, preventing the gravel stone from perforating the tube that the impacted longitudinal element protects. It in this sense that the longitudinal elements are longitudinal protection elements 2 of the tubes.

The or each longitudinal element 2 extends parallel to the longitudinal axis of the tube that it protects. The longitudinal element 2 thus forms an elongate protection element of the tube. This or each longitudinal element 2 takes the form of a strip or cord. The section of the longitudinal element 2 is for example circular, oval, rectangular or square.

In accordance with one embodiment, the frame 3 comprises at least one upright 4 that extends transversely to a direction in which the longitudinal elements 2 extend. Such an upright 4 joins at least two longitudinal elements 2, but it will be clear that in the example shown in Figure 1 the upright 4 joins each of the longitudinal elements 2 and mechanically secures the longitudinal elements 2 relative to one another, determining between these longitudinal elements 2 a space corresponding in particular to a transverse distance that separates two tubes of the heat exchanger. Figure 1 shows the presence of four uprights 4, but it is clear that the invention is not limited to that number and that the protection device 1 could comprise more than four or fewer than four uprights 4. The or each upright 4 lies in a plane parallel to and advantageously coinciding with the plane A in which the series of longitudinal protection elements A lies. Instead of or in addition to the upright described above, the frame 3 may comprise a surround 5 that peripherally surrounds the series of longitudinal protection elements 2. This surround 5 then forms a structural element capable of carrying the series of longitudinal protection elements 2. The surround 5 also has the function of mechanically connecting the protection device 1 to the heat exchanger. The surround 5 has a parallelepipedal shape, for example, in particular a rectangular shape. It has two longitudinal sides 6 joined to one another by two lateral sides 7. In accordance with the Figure 1 example, the series of longitudinal protection elements 2 is fastened to the lateral sides 7 of the surround 5. In the situation where the frame 3 comprises uprights 4, the latter are connected to the longitudinal sides 6 of the surround 5, for example extending parallel to the lateral sides 7 of the surround 5.

The protection device 1 also comprises attachment means 8 configured to fasten the protection device 1 to the heat exchanger. In the embodiment shown in Figure 1 , the attachment means 8 are formed by fixing lugs 9 that protrude from the frame 3, in particular from the surround 5. These fixing lugs 9 lie in a plane transverse to the plane A in which the series of longitudinal protection elements 2 is inscribed, in such a manner as to be attached to an outlet face of the heat exchanger. The protection device 1 is a one-piece component made of two distinct materials. A first material is used for its mechanical retention properties in order to form a structure of the protection device 1 , that is to say the frame 3 described above. The second material is used for its damping properties, and more particularly for its shock-absorbing properties. The second material is used for the manufacture of the series of longitudinal protection elements 2 arranged to protect one side of the tubes of the heat exchanger against which the protection device 1 is pressed. The protection device 1 is therefore a two-material member manufactured by a co- moulding process or by an overmoulding process, the second material then being overmoulded onto the first material. The first material is a polymer material. By way of example, the first material constituting the frame 3 is a polypropylene or a polyamide. Either of those polymers may be reinforced by glass or carbon fibres. These fibres may equally be natural fibres. Finally, these polymers may be reinforced by talc or chalk.

The second material is a polymer material. For example, the second constituent material of the series of longitudinal protection elements 2 is a thermoplastic elastomer, for example thermoplastic polyolefin (TPO), vulcanized thermoplastic elastomer (TPE), thermoplastic polyurethane (TPU), thermoplastic polyamide (TPA), styrenic block copolymers (TPS) based on SBS or on SEBS (two-phase sequenced copolymers containing rigid blocks and flexible blocks), or thermoplastic copolyester (TPC) type. In another example, the second material is a physical mixture of thermoplastic and elastomer of ethylene-propylene-diene monomer (EPDM) or propylene (PP).

The second material is more flexible than the first material. By way of example, the modulus of elasticity of the first material is between 2300 and 16000 MPa inclusive whilst the modulus of elasticity of the second material is between 1 .5 and 100 MPa inclusive. In a different frame of reference, the impact resistance of the first material is between 3 KJ/m ² and 90 KJ/m ² inclusive. The Shore A hardness of the second material is between 20 and 95 inclusive. The elongation at rupture of the second material is between 300% and 1000% inclusive. Here it is clear that the first material imparts mechanical strength to the protection device 1 by carrying the series of longitudinal protection elements 2 whilst the second material imparts the property of absorbing shock, in particular shock caused by projectiles such as gravel.

Figures 2 and 3 show the heat exchanger device 10 that comprises the heat exchanger 1 1 and the protection device 1 . This heat exchanger device 10 is represented in an orthonormal system of axes Oxyz, where the direction Ox illustrates a direction along which a second fluid 25 can move on passing through the heat exchanger device 10 whilst the direction Oy illustrates a direction perpendicular to the direction Ox and along which a first fluid 24 can move in the heat exchanger 1 1 . Finally, the direction Oz is perpendicular to the other two directions mentioned above and illustrates a verticality of the heat exchanger device 10.

The heat exchanger 1 1 comprises a bundle 12 of tubes 13 and dissipation elements 14 organized in an alternating stack of tubes and dissipation elements in the direction Oz. In Figure 2, some longitudinal elements 2 of the protection device 1 have been intentionally concealed to show the tubes 13 of the bundle 12. There are as many longitudinal protection elements 2 as there are tubes 13, the tube 13 then being covered by a longitudinal element 2.

The tubes 13 of the heat exchanger 1 1 are disposed horizontally flat and are configured to have the first fluid 24 pass through them, for example a heat transfer fluid such as water containing glycol when heat exchanger 1 1 is a radiator, a refrigerant fluid when the heat exchanger 1 1 is a condenser or a gas cooler or an incoming airflow when the heat exchanger 1 1 is a turbocharger air cooler. Each tube 13 is formed of two large longitudinal walls 22 joined by two small longitudinal walls, thereby delimiting a channel for circulation of the first fluid 24. Each of the small longitudinal walls forms one side 23 of the tube 13, one of these sides being exposed to the second fluid 25 that passes through the bundle 12 of the heat exchanger 1 1 .

The dissipation elements 14 are for example fins or spacers provided with slatted blinds, each fin or spacer being disposed between two immediately adjacent tubes 13. The space between two tubes 13 where a dissipation element 14 is disposed is intended to have the second fluid 25 pass through it, for example a flow of air from outside the vehicle that is to receive the heat exchanger device 10. A transfer of calories therefore occurs between the first fluid 24 and the second fluid 25 via the tubes 13 and the dissipation elements 14.

In the direction Ox the heat exchanger 1 1 is delimited by an inlet face 15 and by an outlet face 16. The inlet face 15 is that which is intended to have the second fluid 25 pass through it when the latter enters the bundle 12 of the heat exchanger 1 1 whilst the outlet face 16 is that which is intended to have the second fluid 25 pass through it when the latter leaves the bundle 12 of the heat exchanger 1 1 . The inlet face 15 lies for example in a plane parallel to and advantageously coinciding with a plane passing through the side of each tube 13 of the bundle 12.

In the direction Oy the heat exchanger 1 1 is delimited by a first manifold box 17 and by a second manifold box 18, each disposed at one longitudinal end of the tubes 12. The first manifold box 17 comprises a first sleeve 19 and a second sleeve 20 through which the first fluid 24 is able to enter or to leave the heat exchanger 1 1 . The heat exchanger 1 1 finally comprises at least one fixing device 21 by means of which the heat exchanger device 10 may be fastened to a front face of a motor vehicle.

In the direction Oz the stack of tubes 13 and of dissipation elements 14 is flanked by two flanges 26 that extend longitudinally from the first manifold box 17 to the second manifold box 18.

The protection device 1 is disposed on the heat exchanger 1 1 so that the series of longitudinal protection elements 2 is disposed facing, that is to say opposite and in front of, the inlet face 15. The plane A in which the series of longitudinal protection elements 2 lies is therefore parallel or substantially parallel to the inlet face 15 of the heat exchanger 1 1 and a projection of the series of longitudinal protection elements 2 is superposed on the sides of the tube 13 that form the inlet face 15.

As seen in Figure 3, at least one of the longitudinal elements 2, and advantageously all the longitudinal elements 2 of the series, cover(s) the side 23 of a tube 13. In other words, each longitudinal element 2 conceals the side 23 of the tube 13 with which it is associated. It is in this sense that a longitudinal element 2 is placed in front of a side 23 of a tube 13. The side 23 of the tube 13 is therefore protected by the longitudinal element 2, the latter being made from a shock- absorbing material.

It will be noted that in figures 2 and 3 the frame 3 is pressed against the inlet face 15 of the heat exchanger 1 1 . The surround 5 surrounds the bundle of tubes 13 whilst the uprights 4 lie in front of the inlet face 15. The attachment means 8 are used to fasten the protection device 1 to the heat exchanger 1 1 , along the flanges 26 of the bundle 12 and coming to hold onto the outlet face 16 of the heat exchanger 1 1 .

Figure 3 shows a vertical cross section of the bundle 12 of the heat exchanger device 10 between two uprights 4 taken along the line l-l in Figure 2. This Figure 3 shows more particularly the shape of a section of the longitudinal elements 2 constituting the series of longitudinal protection elements 2. In this example, this section is circular and the diameter of this section is at least equal to a thickness of the tubes 13, that is to say a distance measured between the large longitudinal walls 22 and perpendicularly to at least one of those walls. Of course, this is merely one example and the section of the longitudinal element could be any shape as long as that section covers the side 23 of the tube 13.

Of course, the features, the variants and the various embodiments of the invention may be associated with one another, in diverse combinations, provided that they are not incompatible or mutually exclusive. In particular variants of the invention might be imagined comprising only a selection of features described hereinafter independently of the other features described if that selection of features is sufficient to confer a technical advantage or to distinguish the invention from the prior art.