FR2907889A1 - Control valve assembly for heat exchange device, has fixation unit i.e. clamp, fixing valve body to heat exchanger, where unit is made of thermal conductive material and arranged for forming thermal bridge between body and exchanger - Google Patents

Abstract

The valve assembly (2) has a fixation unit i.e. clamp, fixing a valve body (21) to a heat exchanger (1). The fixation unit is made of thermally conductive material, and is arranged for forming a thermal bridge between the body and the exchanger. The fixation unit includes fitting surfaces formed from flanges (31) and projections, with the exchanger, where the surfaces are in continuity with the exchanger and/or the body. The clamp includes the projections with the exchanger and the flange with the valve body.

Description

The present invention relates to fluid transport circuits such as

  than those used in motor vehicles, in particular to recirculate the exhaust gases of the engines of these vehicles. BACKGROUND OF THE INVENTION An exhaust gas recirculation circuit for the engine of a motor vehicle (commonly known as EGR for "Exhaust Gas Recirculation") extends between the exhaust circuit and the exhaust circuit. admitting the heat engine and conventionally comprising a heat exchanger for cooling the exhaust gas, an uncooled bypass channel, a bypass valve for selectively directing the gas flow into the heat exchanger or the bypass duct , and a control valve for adjusting the flow rate of the gas stream in the recirculation circuit. The space available in the engine compartment of the vehicle is increasingly restricted, making it difficult to implement the current recirculation circuits and limiting the cooling possibilities of the components of the recirculation circuit which are subjected to the high temperature of the gases. exhaust. OBJECT OF THE INVENTION An object of the invention is to provide a means for solving the aforementioned drawback. SUMMARY OF THE INVENTION For this purpose, it provides, according to the invention a valve for heat exchanger comprising a valve body provided with means for its attachment to the heat exchanger, the fixing means being thermally conductive and arranged to form a thermal bridge between the valve body and the exchanger. Thus, a more compact valve-exchanger assembly can be obtained. In addition, the connection means 2907889 2 allow the establishment of a heat exchange between the valve and the exchanger thereby allowing cooling of the valve. The invention also relates to a heat exchange device 5 comprising an exchanger and such a valve. Other features and advantages of the invention will become apparent on reading the following description of particular non-limiting embodiments of the invention. BRIEF DESCRIPTION OF THE DRAWINGS Reference is made to the accompanying drawings, in which: FIG. 1 is a perspective view of a heat exchanger associated with a valve assembly in accordance with the invention; FIG. this heat exchanger in section along the plane II of FIG. 1, the shutter being in the position of connection of the valve assembly 20 with the exchanger, FIG. 3 is a partial view, similar to that of FIG. 2, showing the valve assembly when the flap is in a bypass position, - Figure 4 is a fragmentary perspective exploded view of the heat exchanger equipped with the valve assembly according to the invention, FIG. 5 is a partial perspective view of the body of the heat exchanger, FIG. 6 is an end view of the body of the heat exchanger according to a first embodiment, FIG. 7 is a similar view. in Figure 6 of the body of the heat exchanger according to a second embodiment, FIG. 8 is a view similar to that of FIG. 6 of the body of the heat exchanger according to a third embodiment, FIG. 9 is a view similar to that of FIG. FIG. 6 of a heat exchanger according to a fourth embodiment; FIG. 10 is a view similar to that of FIG. 2, of the heat exchanger according to the fourth embodiment; FIG. partial view with skin of the body of a heat exchanger with a particular channel partition profile, - Figure 12 is a view similar to that of Figure 6 of a heat exchanger body according to a fifth mode embodiment, - Figures 13 and 14 are end views of the body of the exchanger according to alternative embodiments, before assembly. DETAILED DESCRIPTION OF THE INVENTION The invention is here described in application to an exhaust gas recirculation circuit of a motor vehicle engine. In a manner known per se, the recirculation circuit is provided with means of its connection on the one hand to the exhaust circuit of the engine and on the other hand to the intake circuit of the engine. The operating principle of such a recirculation circuit is known in itself and will not be detailed below. With reference to FIGS. 1 to 6, the exhaust gas recirculation circuit comprises a heat exchange device comprising a heat exchanger, generally designated 1, associated with a valve assembly, generally designated 2. Heat exchanger 1 comprises a body generally designated 3, having an outer shell 4, 2907889 4 of tubular shape, having open ends 4.1, 4.2. The outer casing 4 here has a parallelepipedal shape and comprises walls 4.3, 4.4, 4.5 and 4.6 parallel and opposite two by two.

In the outer casing 4, two central partitions 5 extend parallel to each other and to a longitudinal axis 6 of the outer casing 4. The central partitions 5 have opposite longitudinal edges connected to the walls 4.3, 4.4 to define therewith a central channel 7. The central channel 7 comprises enlarged portions 7.1, 7.2 in the vicinity of the walls 4.3, 4.4 so that the central channel 7 has a cross-section here in the form of I. The portions 7.1 , 7.2 communicate outside the outer casing 4 by openings 8.1, 8.2 formed respectively in the walls 4.3, 4.4 in the vicinity of the ends 4.1, 4.2 of the outer casing 4. In the outer casing 4 Peripheral partitions 9 extend parallel to each other and to the longitudinal axis 6. The peripheral partitions 9 extend on either side of the central channel 7 and have opposite longitudinal edges respectively connected to the walls 4.5. , 4.6 e t to the central partitions 5 so as to define therewith peripheral channels 10. The peripheral channels 10 here have a rectangular cross section. The central channel 7 has a section greater than that of the peripheral channels 10. The body 3 is made of aluminum by extrusion 30 so that at the exit of the extruder, the channels 7 and 10 have open ends. Extrusion manufacturing makes it possible to obtain a one-piece body, which limits assembly operations and minimizes manufacturing costs. The body 3 can also be made of a metal other than aluminum and more generally any material having sufficient thermal conduction properties. On the ends 4.1, 4.2 of the ex-dull envelope 4 are fixed independent fluid circuit defining members 5. These members comprise two closure elements 11, 12 fixed by welding at the ends of the central channel 7, respectively on the end-end 4.1 and end-4.2 side of the outer casing 4.

These members also comprise a return element 13 which has the shape of a cap having a cylindrical segment bottom wall with an axis perpendicular to the walls 4.5, 4.6 and which is fixed on the end 4.2 of the casing 4. The return element 13 makes it possible to return a flux coming from some of the peripheral channels 10, in this case those identified 10.a extending in the upper half of the outer envelope 4, towards the other peripheral channels 10, i.e. those identified 10.b extending in the lower half of the outer shell 4 (see more particularly Figs. 5 and 6). These members further comprise a connecting element of the ends of the peripheral channels 10, if-killed at the end end 4.1, to supply ducts 25 and fluid discharge. This connecting element is here formed by the valve assembly 2. The valve assembly 2 comprises a valve body 21 having an end portion arranged to form a manifold 22 and an end portion 23 delimiting a first conduit 24 opening into the manifold 22 by a seat 25 for a valve 26 movably mounted in the neck-reader 22 between an extreme position of closure and an extreme open position of the first conduit 24. The end portion 23 is equipped with means for connecting the first conduit 24 to an external pipe. The collector 22 extends the first conduit 24 and here forms a flared end thereof. The valve 26 is connected to the rod of an actuator 27 mounted outside the valve body 21 on the side of its end portion 23. The action 27, known in itself, is arranged to make adjustably slid the valve 26 between its two positions. The collector 22 also defines a second duct 28 opening into the collector 22 on the side of the wall 4.3 and perpendicular to the longitudinal axis 6. The second duct 28 is an inlet duct of a gas flow in the set of valve 2 and the first duct 24 is an outlet duct of the gas stream of the valve assembly 2. The second duct 28 is thus intended to be connected to the exhaust circuit of the heat engine and the first duct 24 is intended to be connected to the intake duct of the engine. The collector 22 is fitted between two flanges 31 of a flange, generally designated 30, fitted and fixed by welding on the end 4.1 of the ex-dull envelope 4. The flanges 31 are parallel to the walls 4.5, 4.6 of FIG. the outer casing 4 and are provided with bearings pivotally receiving an axis 32 of a double flap, generally designated 33, having two flap portions 33.1, 33.2 extending in the extension of each other. either side of the axis 32. The flange 30 comprises interlocking surfaces formed of two fins (or projections) 40, 41 parallel to the walls 4.3, 4.4 between which the exchanger is fitted.

The flange 30 and the flap 33 define an inlet opening 34 in the exchanger 1 facing the peripheral channels 10.a and an outlet opening 35 of the exchanger 1 opposite the peripheral channels 10.b. The flap 33 is mounted opposite the second duct 28 and the opening 34 and is movable between a bypass position (FIG. 3) in which the flap 33 deflects a gas flow coming from the second duct 28 directly to the first duct 28. led 24 without passing through the heat exchanger 1 and a connection position 5 (Figure 2) in which the flap 33 guides the gas flow from the second conduit 24 to the inlet opening 34 and the outlet opening 35 to the first duct 24. In the connection position, the lateral and end edges of the flap portion 33.1 respectively bear against sealing surfaces 36, 37 forming a seat extending into the collector 22 and belonging to the body. valve 21; the side and end edges of the flap portion 33.2 are respectively sealing against seat surfaces 38, 39 belonging to the flange 30. The surfaces 36, 37 extend from one side of the bearings opposite the surfaces 38 39. The flap 33 in the connection position thus isolates the portion of the collector 22 into which the second conduit 28 opens out of the portion of the collector 23 into which the first duct 24 opens. In the bypass position, the flap 33 deflects the flow As the inlet and outlet of the exchanger both open into the valve body behind the flap, there is no circulation in the heat exchanger even if the heat exchanger The surface 39 belongs to a cross member of the flange 30 which is secured to the shutter element 11 of the central channel 7. Due to the structure of the flange 30 and divides it Because of the surfaces 36, 37, 38, 39 forming the flap seat 33 between the valve body 21 and the flange 30, the flange 30 is compact and allows a small distance between the valve body 21 to be obtained. and the body 3 of the exchanger 1. The flange 30 is made of a thermally conductive material and constitutes a thermal bridge between the valve body 21 and the body 3 of the exchanger 1.

To improve the heat exchange between the valve body 21 and the body 3 of the heat exchanger 1, the collector 22 is provided with a thermally conductive fin 29 which extends perpendicular to the axis 32 of the flap 33 and which it bears on the body 3 of the exchanger 1, here indirectly via the shutter element 11, made of thermally conductive material. The fin 29 thus promotes thermal conduction between the body 3 of the exchanger 1 and the valve body 21.

The return element 13 and the flange 30 comprise end-pieces 14, 15 intended to extend opposite the apertures 8.1, 8.2 to allow the connection of ducts to the central channel 7. These end-pieces 14, 15 are welded to the walls. 4.3, 4.4 and are intended to be connected to pipes carrying a heat transfer fluid. The central channel 7 thus transports the coolant which will allow the cooling of the exhaust gases that will circulate in the peripheral channels 10. The central partitions 5 are thus in contact with the coolant and the gases to be cooled and allow a transfer direct thermal between them, and the peripheral partitions 9 provide heat transfer between the gases to be cooled and the heat transfer fluid via the central partitions 5. The use of a central channel for the coolant and peripheral channels surrounding the central channel for the fluid to be cooled provides a compact and efficient heat exchanger structure by promoting heat transfer by convection and conduction. In addition, a single central channel for the heat transfer fluid allows the lengths to be sealed to be limited and minimizes the risk of leakage. Note further that, the shutter member 11 being in contact with the heat transfer fluid, the element 5 promotes the cooling of the fin 29 and therefore of the valve body 21. The components welded to the body 3 of the exchanger are laser welded. According to a second embodiment, the valve assembly 2 and the return element 13 are arranged in such a way that the channels 10.a extend on one side of the central channel 7 opposite to the channels 10.b. see Figure 7). According to a third embodiment, as shown in FIG. 8, the body 3 of the exchanger 1 comprises only four main peripheral channels 110 made in the mass of the body 3, each of these peripheral channels 110 being subdivided into a plurality of peripheral sub-channels 111 through a zigzag wall 112 attached to each peripheral channel 110. To create turbulence and increase the efficiency of the heat exchanger, these zigzag walls 112 may have reliefs, for example embossing, to create turbulence in the gas flow.

Although the invention has been described in relation to a U-shaped heat exchanger, the invention is of course applicable to an I-shaped heat exchanger as in the fourth embodiment shown in FIGS. 9 and 10. The body 203 of the exchanger is then connected to the valve body 221 which defines a single conduit 224 while the opposite end of the body 203 is connected to an external conduit by a connecting element 252. In this arrangement, the central channel 207 is identical to the central channel 7 previously described, all the peripheral channels 210 of the body 203 of the exchanger are unidirectional and the body 203 of the exchanger comprises two additional channels, namely a bypass channel 250 uncooled and an isolation channel 251 containing air and thermally isolating the bypass channel 250 of the center channel 207. The valve body 221 of the valve assembly 202 is fixed to the body 203 of the exchanger by a flange 230 having a single flap 233 movable between a position 10 connecting the duct 224 to the peripheral channels 210 and a bypass position in which the duct 224 is connected to the branch channel 250 It will be appreciated that the isolation channel 251 is optional.

According to a fifth embodiment, represented in FIG. 12, the body 3 of the heat exchanger comprises two peripheral partitions 300, parallel to the walls 4.5, 4.6, having longitudinal edges connected to the walls 4.3, 4.4 to define with them ci and with the walls 4.5, 4.6 of the main channels 301 for the passage of heat transfer fluid. Between the peripheral walls 300 extend central partitions 302 delimiting central channels 303 of smaller section than the main channels 301 and intended for the passage of the gases to be cooled. Of course, the invention is not limited to the embodiments described and variants can be made without departing from the scope of the invention as defined by the claims.

In particular, the body of the heat exchanger may have a different structure from that described and result for example from the combination of one or more of the embodiments described or result from an assembly of different parts. The number of channels may be different and the sections thereof may not be rectangular. The outer envelope and the central channel may thus have a circular section and the peripheral channels a section into annular segments. Alternatively, the body may comprise at least one extruded portion incorporating at least some of the partitions delimiting (wholly or in part) a plurality of channels. Thus, as shown in FIGS. 13 and 14, the body 3 of the exchanger may result from the assembly of several extruded parts (the body 3 remains an "extruded body" in the sense of the present description. a first extruded part 3.A forming the envelope 4 and a second part 3.B delimiting the channels 3.B comprises a central portion comprising the two central partitions 15 whose adjacent longitudinal edges are connected. by partitions 5 'to delimit the central channel 7 which is only open at its ends before the introduction of the shutter elements 11, 12 (not visible here) Central partitions 5 extend the partitions 3.B is mounted in part 3.A so that the walls 4.3, 4.4, 4.5 and 4.6 delimit the peripheral channels 10 with the peripheral walls 9. It is not necessary to fix the free ion-gitudinal edges of c peripheral lobes 9 to the casing 4, a sealing of the peripheral channels 9 relative to each other not being necessary for the proper operation of the exchanger 1. In contrast, the central channel 7 is longitudinally watertight him even before the 30 mounting part 4.8 in part 4.A, the risk of leakage of heat transfer fluid to be avoided. It will be noted that ribs 70 project from peripheral partitions to increase the exchange surface area with the gas flow.

In FIG. 14, two identical ex-truss portions forming half-bodies 3.A ', 3.B' may each be de-limiting each: a longitudinal portion of the walls 4.3 and 4.4; one of the walls 4.5, 4.6; one of the central partitions 5 and the peripheral partitions 9.

The half-bodies 3.A ', 3.B' are joined to form the central channel 7 and are connected to each other by a longitudinal weld extending along the walls 4.3 and 4.4. Furthermore, other sounding methods than the laser probing mentioned in the description of the previous embodiments may furthermore be used for producing the exchanger. As a variant, the partitions of the body of the exchanger may locally have plastic deformations intended to generate turbulence in the gas flow. These partitions may for example be corrugated as shown in Figure 11. The seat surfaces for the flap can be made on the flange only. Seat-forming surfaces may also be provided on the valve body, either for only one of the positions of the flap, or for both positions of the flap. In the connection position, the edges of the flap 33 may be spaced apart from the seat surfaces belonging to the valve body 21 and the flange 30 of a distance less than a minimum clearance clearance. By this is meant that there is no impervious support of the shutter on these surfaces but that a space extends between them, this space being of sufficiently small dimensions that the resulting leakage is not not detrimental to the operation of the heat exchange device. It is also possible to arrange the valve assembly so that the shutter in the bypass position cooperates with seat surfaces belonging to the valve body 35 and / or the flange.

The fin 29 is optional or may be replaced by any thermally conductive element capable of forming a thermal bridge such as one or more material thicknesses.

The flow direction of the gases in the valve assembly and the exchanger can of course be reversed with respect to that described. The second duct may be delimited by the flange.

The valve body can be attached directly to the body of the exchanger. The valve body and the flange can be in one piece. The structure of the valve body may be different as well as the structure of the shutter element 15 and / or regulation formed here by the valve. The form of the fastening means may be different from that shown: the fastening means may comprise interlocking surfaces with the exchanger, the engagement surfaces being continuous with the exchanger and / or the valve body (conversely the interlocking surfaces can be attached to the flange, the exchanger or the valve body); The fastening means are arranged in the vicinity of an opening for communication with the exchanger and the interlocking surfaces comprise projections of the body and / or the flange, the projections extending over a whole period of time; the projection of the communication opening (the projections 240 thus extend all around the opening in FIG. 10 to fit the exchanger) or, the opening being rectangular, the projections 40, 41 extending from two opposite sides of the opening.

Claims (18)

  1. Valve (2) for heat exchanger (1), comprising a valve body (21) provided with means for its attachment (30) to the heat exchanger, characterized in that the fixing means are thermally conductive and are arranged to form a thermal bridge between the valve body and the exchanger.   2. Valve according to claim 1, wherein the fastening means comprise interlocking surfaces (31, 40, 41) with the exchanger.   3. Valve according to claim 2, wherein the interlocking surfaces are in continuity of material with the exchanger and / or the valve body.   4. Valve according to claim 2, wherein the fixing means comprise a flange (30) having said interlocking surfaces (40, 41) with the exchanger (1) on the one hand and interlocking surfaces (31). ) with the valve body (21) on the other hand.   5. Valve according to claim 4, wherein the fixing means are disposed in the vicinity of a communication opening with the exchanger (1) and the interlocking surfaces comprise projections (31, 40, 41 of the body and / or the bridle.   The valve of claim 5, wherein the projections (240) extend over an entire periphery of the communication aperture.   The valve of claim 5, wherein the opening is rectangular and the projections (40, 41) extend from two opposite sides of the opening.   8. Valve according to claim 4, wherein a flap (33) is mounted in the flange for pivoting between a connection position of the duct (24) to the exchanger (1) and a bypass position in which the duct is not connected to the exchanger. 2907889 15   Valve according to claim 8, wherein the valve body (21) and the flange (30) comprise seat-forming surfaces (36, 37, 38, 39) for the flap (33) when it is in least one of its positions.   10. Valve according to claim 9, wherein the flap (33) in said at least one of its positions bears against the surfaces (36, 37, 38, 39) forming a seat. 10   11. A valve according to claim 9, wherein the flap (33) in said at least one of its positions is spaced from the seat surfaces of a set of low leakage.   12. A valve according to claim 9, wherein the flap (33) is a double flap having a pivot axis (32) on either side of which flap portions extend symmetrically, the seat surfaces (36) being 37) of the body (21) being symmetrically opposed to the flange-like surfaces (38, 39) of the flange (30) relative to the pivot axis (32).   Valve according to claim 9, wherein the seat-forming surfaces (36, 37, 38, 39) of the body (21) and the flange (30) cooperate with the flap (33) when the latter is in its position. connection. 25   14. Valve according to claim 8, the body de-limiting a first duct (24) and a second duct (28) forming an inlet duct and an outlet duct of the valve, and the flange (30) defining an opening. input port (34) and an outlet opening (35) of the sampler (1), the flap (33) in the connecting position communicating with the inlet duct and the outlet duct of the the valve with the inlet duct and the outlet duct of the exchanger respectively and the vo-let in the bypass position putting the inlet duct of the valve in communication directly with the duct 2907889 16 of the valve outlet .   Valve according to claim 14, in which the second duct (28) is delimited by the valve body (21). 5   16. Valve according to claim 1, wherein the valve body (21) comprises at least one thermally conductive element (29) extending in the conduit (24) from the seat (25) to the exchanger (1).   Valve according to claim 16, wherein the thermally conductive element is a fin (29).   18. Heat exchange device comprising a heat exchanger (1) and a control valve (2) according to any one of the preceding claims.