FLUID CONNECTION AND FLUID HEATING DEVICE

Description

Domaine technique de l'invention

[0001] The present invention relates in particular to a fluid connection and fluid heating device, in particular for a motor vehicle, this device being able for example to be used for an application such as the connection of an air intake nozzle to a gas leak pipe of an internal combustion engine. Arrière-plan technique

[0002] A gas leak pipe of an internal combustion engine, for the passage of gases from the combustion chamber to the engine crankcase, is widely known by the English name " blow-by ". Generally speaking, the function of quick connectors in motor vehicles is to connect fluid transfer pipes to the engine components. In particular, fluid connection and heating devices are used in pollution control systems where the gaseous residues from the engine combustion that accumulate in the engine crankcase and which contain water in particular are reinjected into the air intake pipe. In very cold weather, this water can freeze and cause the pipe to become blocked, which, in the event of total blockage, can cause an increase in pressure in the crankcase, leading to the evacuation of the lubricating oil contained in the crankcase through the gauge ports. This can result in significant damage to the engine.

[0003] In the current technique, such a connection device comprises means for heating the fluid. The fluid to be heated circulates in a tube which is heated.

[0004] Document FR-A1-2 943 718 describes a fluid connection device for this application.

[0005] Another application for a heated fluid connection device is an SCR (Sensor Controlled Refrigeration) decontamination circuit. Selective Catalytic Reduction ). In document EP-A1-2 363 627, a fluid line comprises a heating wire which is wrapped around a plastic fitting for this further application.

[0006] However, these technologies are not entirely satisfactory because the devices are complex and therefore time-consuming and expensive to produce. Using a heating wire, for example, requires manual winding of the wire around the connection, and the quality of this manual operation has an impact on the quality of the heating and its reproducibility.

[0007] There is therefore a need for a fluid connection and fluid heating device that includes a limited number of parts so as to simplify its manufacture and reduce its manufacturing cost. Résumé de l'invention

[0008] The present invention provides an improvement to the aforementioned technologies which makes it possible to meet the needs of the prior art.

[0009] The present invention relates to a fluid connection and fluid heating device for a fluid circuit, in particular for a motor vehicle, this device comprising a single-piece tubular body made of plastic or composite material comprising: an inlet and an outlet each equipped with fluid connection means, which are of the force-fitting or male / female cooperation type, at least one internal annular surface defining a fluid flow path from the inlet to the outlet of the body, and at least one external annular surface extending around the path and on which is located at least one resistive heating element, such that the resistive heating element is a resistive circuit which comprises at least one elongated resistive track whose longitudinal ends are connected to electrical connection terminals which are oversized relative to the or each track so as to be connected to wires or electrical terminals, said circuit being formed in situ on said at least one outer annular surface. The resistive element is thus in the form of a circuit which is directly formed on at least one annular surface of the body of the device. The formation of the heating circuit directly on the body makes it possible to eliminate the step of mounting the resistive element of the prior technology, as well as the disadvantages associated with it. This also makes it possible to produce a series of bodies with identical heating circuits and therefore with identical fluid heating capacities. The formation in situ of the circuit also makes it possible to eliminate any space or play between the resistive element and the body, which tends to harm the heating efficiency of the fluid.

[0010] According to the invention, the circuit extends continuously over several adjacent external annular surfaces.

[0011] The terminals are also formed directly on the body, which facilitates the electrical connection of the track. For this, the terminals are oversized compared to the track and in particular are widened (they include a width greater than that of the tracks) so that each one is able to receive a solder point.

[0012] The device according to the invention may comprise one or more of the following characteristics, taken in isolation from one another or in combination with one another: the resistive track forms a serpentine; the resistive track has a width less than or equal to 5 mm, and for example less than or equal to 1 mm; the terminals are soldered to the ends of electrical wires or to electrical terminals; - electrical terminals are integrated into the body and connected to the terminals by simple contact; the circuit extends all around said at least one external annular surface; said at least one external annular surface is cylindrical or frustoconical; the circuit extends over the entire periphery of a bottom of an annular groove; the circuit has a thickness less than or equal to 0.5 mm; the circuit extends over a surface representing at least 100 mm 2< , and preferably at least 250 mm 2< ; the circuit has a length of between 5 and 100 mm, and for example between 5 and 50 mm, and a diameter of between 6 and 80 mm; the circuit is configured to provide a thermal power between 0.5 and 10W;and the circuit is at least partially covered and protected by a body coating material, for example thermoplastic; and -- a passivation layer or dielectric layer covers at least part of the circuit and in particular said at least one track; -- said passivation layer or dielectric layer covers contact or soldering points for connecting the terminals to the wires or electrical terminals. ;

[0013] The present invention also relates to a fluid circuit, in particular for a motor vehicle, comprising at least one device as described above. This is for example an SCR circuit.

[0014] The present invention also relates to a method of manufacturing a device as described above, in which it comprises a step of producing the circuit by a technique chosen from printing a resistive or conductive ink and selective metallization.

[0015] A resistive ink is often an ink with a semiconducting charge (carbon type). It would also be possible to make a resistive track with a conductive ink (charged with metal) by adapting for example the dimensions of the track. Selective metallization can be carried out by laser (optional) then immersion in one or more metallization baths (electrolytic or non-electrolytic deposition). The laser can be used to carry out a chemical modification of the treated surface and / or to increase the roughness of this surface.

[0016] The body material may include an additive intended to be activated by laser and to facilitate the adhesion of one or more layers of metal during immersion or successive immersions.

[0017] Alternatively, the body material could not contain a laser-activatable additive and the body surface could be chemically activated by immersion in one or more chemical activation baths before being metallized.

[0018] The body can be produced by two-material injection into a mold, of a first material having an affinity with an electroconductive and resistive material, and of a second non-electroconductive material.

[0019] The ink can be printed by inkjet, aerosol jet, stamping, or any other suitable technique. Brève description des figures

[0020] Other characteristics and advantages of the invention will appear during the reading of the detailed description which follows for the understanding of which reference will be made to the appended drawings in which: [ Fig. 1 ] there figure 1 is a schematic perspective view of a fluid connection and fluid heating device according to one embodiment of the invention; [ Fig. 2 ] there figure 2 is another schematic perspective view of the device of the figure 1 ; [ Fig. 2a ] there figure 2a is a very schematic sectional view of a device and more specifically shows the electrical connection of a wire to a terminal of the resistive circuit of the device; [ Fig. 2b ] there figure 2b is a very schematic sectional view of a device and more specifically shows the electrical connection of a terminal to a terminal of the resistive circuit of the device; [ Fig. 3 ] there figure 3 is a larger-scale schematic view of a detail of the device of the figure 1 ; [ Fig. 4 ] there figure 4 is a schematic perspective view of a fluid connection and fluid heating device according to an alternative embodiment of the invention; [ Fig. 5 ] there figure 5 is a schematic perspective view of a fluid connection and fluid heating device covered with a coating material; and [ Fig. 6a-6f ] THE figures 6a à 6f are very schematic views of an injected plastic body during metallization, and illustrates a metallization process by LDS; [ Fig. 7a-7e ] THE figures 7a à 7e are very schematic views of a plastic body being metallized, and illustrates a laser-assisted selective metallization process (optional step) with a chemical activation step; and [ Fig. 8 ] there figure 8 is a very schematic view of a plastic body during metallization, and illustrates a two-material injection metallization process. Description détaillée de l'invention

[0021] THE figures 1 à 3 illustrate an embodiment of a device 10 according to the invention for fluid connection and fluid heating. The device 10 is particularly designed for use in a motor vehicle.

[0022] The fluid can be a gas or a liquid. Examples include fuel, coolant, exhaust gas from an internal combustion engine, etc.

[0023] The device 10 is part of a fluid circuit such as a fuel supply circuit, an air conditioning circuit, a vacuum brake circuit, an SCR circuit, etc. As its name indicates, the device 10 has a dual function of fluid connection and heating of the fluid that it conveys.

[0024] To ensure fluid connection, it naturally includes fluid connection means and, to ensure heating, it includes heating means.

[0025] The device 10 comprises a body 12 which has a generally tubular shape and which is a single piece. This body 12 may have a straight or bent shape, as in the example shown. It is a single piece, that is to say that it is formed from a single piece, even if additional elements such as fixing elements could be added and fixed to the body 12.

[0026] The body is made of plastic or composite material, and for example of thermoplastic in particular. It can be manufactured by injection molding for example. The body 12 comprises a fluid inlet 14 and a fluid outlet 16. The body 12 further comprises one or more internal annular surfaces 18 which define a vein 20 for the flow of the fluid from the inlet 14 to the outlet 16 of the body. figure 3 is a sectional view of the device 10 and allows one of these surfaces 18 to be seen.

[0027] In the example shown, the device 10 and therefore the body 12 are bent and the transverse dimension of the body 12 varies, and in particular decreases, from the inlet 14 to the outlet 16. It is therefore understood that the internal surfaces 18 are not all coaxial and of the same diameter.

[0028] The body 12 comprises several external annular surfaces 22 which extend around the vein 20 from the inlet 14 to the outlet 16 of the body 12.

[0029] A first fluid connection means 24 is located at the inlet 14 of the body 12 and comprises a cage 26 forming a female part and intended to receive a tip forming a male part. This cage 26 is configured to cooperate with a locking member intended to prevent accidental detachment of the tip from the device 10. One or more seals can ensure the sealing of the connection. This type of fluid connection is well known to those skilled in the art.

[0030] A second fluid connection means 28 is located at the outlet 16 of the body 12 and is of the fir-tree fixing type, which here comprises a single annular anchoring rib 30 projecting from a section 32 of the body 12. This section 32 of the body 12 is intended to be forcefully engaged in the end of a pipe and the anchoring rib 30 is configured to ensure that this section is held in the pipe. This type of fluid connection is well known to those skilled in the art.

[0031] From the cage 26 to the section 32, the body 12 comprises several surfaces 22 and successively a cylindrical surface 22a, one or more annular surface(s) 22b (22c, 22d) defining an annular groove 34, a frustoconical surface 22e, and another cylindrical surface 22f. The connection of the frustoconical surface 22e to the cylindrical surface 22f is made at the elbow of the body 12 by means of a surface 22g in the form of a portion of a sphere.

[0032] The heating means comprise at least one resistive heating element located on at least one of the surfaces 22a-22f of the body 10.

[0033] According to the invention, the resistive heating element is a resistive circuit 36 ​​which is formed in situ on at least one of the surfaces 22a-22f of the body 10.

[0034] The circuit 36 ​​is thus formed directly on the body 10. In the preferred embodiment of the invention where the circuit 36 ​​comprises at least one resistive track 38 of elongated shape whose longitudinal ends are connected to electrical connection terminals 40, the track 38 and the terminals 40 are formed directly on the body 12.

[0035] The conductive and resistive material of the circuit 36 ​​is therefore in contact with the material of the body 12 which is however not conductive. It is however conceivable to provide a passivation layer or dielectric layer between the circuit 36 ​​and the body 12. Such a passivation layer may, as a variant or as an additional characteristic, be provided on the circuit 36 ​​in order to protect it from the external atmosphere.

[0036] The body 12 may be coated in a coating material 48, for example an elastic thermoplastic, as seen in FIG. figure 5 . This coating material 48 covers and protects the circuit 36.

[0037] As mentioned above, one or more tracks 38 extend between the terminals 40. In the example shown, a single track 38 has its longitudinal ends connected to the terminals 40. This track 38 advantageously forms a serpentine with several straight lines (and curved due to the annular shape of the surfaces 22 of the body 12) and several U-shaped back and forths.

[0038] The or each track 38 may have a length greater than or equal to 5 mm, or even 100 mm, or even more. The or each track 38 (or portion of track) may have a width L greater than or equal to 80 µm, and preferably greater than or equal to 100 µm ( figure 3 ). This width is preferably less than or equal to 5 mm. The or each track 38 may have a thickness less than or equal to 10 µm ( figure 3 ).

[0039] Each portion of the or each track 38 can be arranged so as to always be separated by a distance D of between 100 µm and 5 mm from one or more adjacent track portions or from the terminal(s) ( figure 3 ).

[0040] In a particular embodiment of the invention, L≤D≤80 mm. The minimum distance between two portions or turns of the track can be comparable to the width L of the track, which is for example approximately 100-300µm.

[0041] The terminals 40 may have a generally rectangular shape with dimensions of, for example, 1mm x 1mm or 1mm x 2mm.

[0042] The method of realization of the figures 1 à 3 shows a resistive track 38 which extends between the terminals 40 and on the surface 22a, and in particular over its entire periphery. The variant embodiment of the figure 4 shows a resistive track 38 which extends between the terminals 40 all around the surfaces 22a-22f including at the bottom of the groove 34.

[0043] The circuit 36 ​​may extend over a surface or area representing at least 10 cm 2 < . The circuit 36 ​​may have a length H1, H2 of between 5 and 100 mm, and a diameter R1, R2 of between 6 and 80 mm. The circuit 36 ​​may be configured to provide a thermal power of between 0.5 and 10 W. The device 10 may be heated to have a maximum temperature of between approximately 20 and 90°C, and preferably between 40 and 60°C.

[0044] In the examples shown, the terminals 40 are located close to each other, on the surface 22a. They are preferably made of the same conductive and resistive material as the track 38.

[0045] These terminals 40 are used to electrically connect the circuit 36 ​​to a heating control and command device (not shown). The connection can be made by means of two conductive wires 42 whose longitudinal ends are welded respectively to the terminals 40. It is therefore understood that the terminals 40 are advantageously sized to receive a solder point 44 from one end of one of the wires 42. The terminals 40 are therefore oversized relative to the track 38, and in particular widened.

[0046] In the aforementioned case where a passivation layer covers the circuit 36, it is understood that, if this layer is deposited before the electrical connection of the terminals 40, the passivation layer will be deposited on the track 38 and will not be deposited on the terminals to allow the deposition of the solder points 44. If the passivation layer is deposited after the electrical connection of the terminals, this layer may cover the tracks as well as the solder points. In the aforementioned case of the use of a coating material 48, this may be designed to ensure that the points 44 and the wires 42 are held on the body 12. figure 2a illustrates an embodiment showing these features.

[0047] There figure 2b illustrates a variant in which the electrical connection of the electrical terminals to a wire or terminal is not made by soldering ( figure 1 ) but by simple contact. In the case illustrated in the figure 2b , the contact is made by integrating the terminal 45 into the body 12 of the device and then depositing or forming the track 38 and the terminal 40 on the body and the terminal. The circuit and the contact area of ​​the terminal 40 on the terminal 45 are then coated with the coating material 48.

[0048] Circuit 36 ​​can be formed in situ on the body in several ways, and in particular by a plastronics technique. Plastronics brings together all the techniques for printing printed electronics or selective metallization on a rigid plastic or composite substrate and in three dimensions, and is also known under the name MID (which is the acronym for the English Molded Interconnect Device).

[0049] The circuit 36 ​​can be produced for example by a technique chosen from printing a resistive or conductive ink and selective metallization.

[0050] The ink can be printed by inkjet printing for example.

[0051] Selective metallization can be achieved by bi-material injection, of a first electrically conductive and resistive material and a second non-electroconductive material, into a mold for manufacturing the body. It is understood that the first material will form the tracks 38 and the terminals 40 and the second material will form the rest of the body 12.

[0052] Alternatively, the first material could not be conductive but only comprise an additive (such as copper seeds) facilitating the attachment of the circuit 36.

[0053] Alternatively, selective metallization can be achieved by LDS technology (laser direct etching or Laser Direct Structuring in English) which is one of the MID technologies that allows the production of tracks on complex injected parts. The body 12 is manufactured from a material incorporating an organometallic additive ( figure 6a ). Then, a 50 laser beam directly engraves the tracks to activate the material using a physicochemical process between the additive and the laser ( figure 6b ). For fine circuits, metallization is carried out by non-electrolytic deposition. Once this material is activated, the body is immersed in different baths containing metal ions (copper, then nickel, then gold) to produce several successive deposits 52, 54, 56 of metal in the activated zone ( figures 6c-6e ). The successive layers are for example of the type Cu / Ni / Au, Cu / Ni / Ag, Cu / Ni / (Pd / Au), Ni / Pd / Au, Cu / Ni, Cu / Sn, etc. The last step consists of soldering the wires 42 as mentioned above ( figure 6f ).

[0054] The thicknesses of the metal layers are for example; Cu = 15 µm max (preferably between 4 and 10 µm) Ni = 20 µm max (preferably less than 15 µm) Au = 1 µm max (normally 0.11µm with a tolerance of ± 0.05µm)

[0055] The relatively thick layers (greater than 15µm in the case of copper) are produced by electrolytic deposition, i.e. electroplating.

[0056] Metallizable polymers are thermoplastic polymers, liquid crystal polymers (LCPs), some thermosetting resins and some crosslinked elastomers. For applications requiring resistance to high temperatures (110-150°C), thermoplastics such as PA, PPA and PPS are preferred.

[0057] A polymer compatible with LDS generally includes an additive capable of producing germs on the surface of the body by being activated by laser. This can be a copper-chromium oxide (CuO·Cr 2 O 3 ) or an organic complex of Cu or Pd. Typically, a polymer of this type comprises between 1 and 15% by weight of LDS additive, the remainder being formed by the polymer matrix and possible reinforcing fillers.

[0058] Several materials are currently available on the market for LDS applications, including the TECACOMP ®< PEEK LDS black 3980 material marketed by Ensinger, and the Preperm 260 LDS (PPE) material marketed by Premix.

[0059] There are also metallic paints. The paint is sprayed onto a conventional polymer (without LDS additives) to make it metallizable.

[0060] Alternatively, the first material could be non-conductive and not contain a laser-activatable additive. The roughness of the surface of the body could be increased by laser treatment. The activation of the surface could be achieved chemically, as illustrated in figures 7a (plastic injection for example), 7b (optional laser activation), 7c (chemical activation), 7d (rinsing for selective cleaning of particles from the non-activated surface), and 7e (selective non-electrolytic metallization). For example, this activation could be achieved by treating the body with a colloid solution (technology Laser Induced Selective Activation, LISA), typically Pd-Sn chloride. Another example is to use a non-colloid solution (technology Selective Surface Activation by Laser, SSAIL), such as Ag nitride. The body is then rinsed to remove particles of activation solution from the untreated surface, and is then metallized by immersion in a chemical metallization bath (according to the previous protocol).

[0061] Another type of metallization is the metallization called bi-material injection ( Two Shot Molding Or 2K Molding in English), which is illustrated in the figure 8 (from top to bottom, bi-material injection, chemical activation, selective rinsing and selective metallization). The plastic part is molded in two successive injections, by a metallizable material and a conventional material. The first plastic is treated with a chemical mordant (such as chromium acid or potassium hydroxide), then the circuit is deposited by liquid process similar to the LDS technique (non-electrolytic deposition preferred). The metals used, the thickness of the manufactured circuit and the process control are similar to those of the LDS technique.

[0062] These plastronic technologies allow the heating function to be transferred directly to the plastic body, reducing the number of components (wires), which lowers the cost, especially labor.

[0063] There are other selective metallization techniques, such as those known under the Anglo-Saxon names Hot Embossingor Plasmacoat 3D ®< . The first technique can form metallic patterns by stamping on polymers with a low glass transition temperature (Tg). As for Plasmacoat 3D ®< , it involves spraying a metal through a plasma torch. This method allows the depositing of metallic patterns in copper or zinc for example.

Claims

1. A fluidic connection and fluid heating device (10) for a fluid circuit, in particular for a motor vehicle, this device comprising a one-piece tubular body (12) made of plastic or composite material comprising: - an inlet (14) and an outlet (16) each equipped with fluidic connection means, which are of the press-fit or male / female cooperation type, - at least one internal annular surface (18) defining a fluid flow duct (20) from the inlet (14) to the outlet (16) of the body, and - at least one external annular surface (22) extending around the duct and on which is located at least one resistive heating element, the resistive heating element being a resistive circuit (36) which comprises at least one elongated resistive track (38) whose longitudinal ends are connected to electric connection terminals (40) which are oversized relative to the or each track so as to be connected to electrical wires or lugs, said circuit being formed in situ on said at least one external annular surface, characterized in that the circuit (36) extends continuously over a plurality of adjacent external annular surfaces (22a-22f) of the tubular body (12).

2. The device (10) of claim 1, wherein the resistive track (38) forms a serpentine.

3. The device (10) of claim 1 or 2, wherein the resistive track (38) has a width (L) less than or equal to 5mm, and for example less than or equal to 1mm.

4. The device (10) of any of the preceding claims, wherein the circuit (36) extends all-around said at least one external annular surface (22).

5. The device (10) according to any of the preceding claims, wherein said at least one external annular surface (22) is cylindrical or frustoconical.

6. The device (10) of any preceding claims, wherein the circuit (36) extends over the entire circumference of a bottom of an annular gorge (34).

7. The device (10) according to any of the preceding claims, wherein the circuit (36) has a thickness (E) less than or equal to 0.5 mm.

8. The device (10) according to any of the preceding claims, wherein the circuit (36) extends over a surface area of at least 100 mm2, and preferably at least 250 mm2.

9. The device according to any of the preceding claims, wherein the circuit (36) has a length (H1, H2) of between 5 and 100 mm, and a diameter (R1, R2) of between 6 and 80 mm.

10. The device (10) of any of the preceding claims, wherein the circuit (36) is at least partially covered and protected by a coating material of the body, for example thermoplastic.

11. A fluid circuit, for instance SCR, in particular for a motor vehicle, comprising at least one device (10) according to one of the preceding claims.

12. A method for manufacturing a device according to any of claims 1 to 10, wherein it comprises a step of realizing the circuit (36) by a technique selected from printing a resistive or conductive ink and the selective metallization.

13. The method of claim 12, wherein the selective metallization is realized by laser followed by immersion in one or more metallization baths.

14. The method of claim 13, wherein the material of the body comprises an additive intended to be laser activated and to facilitate the attachment of one or more metal layers during the immersion or the successive immersions.

15. The method according to claim 13 or 14, wherein the body is made by two-material injection into a mould, of a first material having an affinity for an electrically conductive and resistive material, and a second, non-electrically conductive material.

16. The method of claim 12, wherein the ink is printed by inkjet or aerosol jet or stamping.