EP2084388A1

EP2084388A1 - Egr/by pass valve unit and heat exchanger device provided with such a valve unit

Info

Publication number: EP2084388A1
Application number: EP07858454A
Authority: EP
Inventors: Laurent Albert; Olivier Delgarde
Original assignee: Valeo Systemes de Controle Moteur SAS
Current assignee: Valeo Systemes de Controle Moteur SAS
Priority date: 2006-10-27
Filing date: 2007-10-16
Publication date: 2009-08-05
Anticipated expiration: 2027-10-16
Also published as: FR2907890A1; WO2008053091A1; EP2084388B1; FR2907890B1

Abstract

The invention relates to a valve unit, comprising a body (21), defining at least one first channel and a valve (26) mounted in the body and which is mobile with relation to a seat (25) formed in the first channel, characterised in that a connector flange (30) for a heat exchanger (1) is mounted on the body, a flap (33) being mounted on the flange such as to pivot between a connecting position for the first channel to the heat exchanger and a bypass position in which the first channel is not connected to the exchanger. The invention further relates to a heat exchanger comprising such a valve.

Description

EGR-BY PASS valve assembly and heat exchange device equipped with such a valve assembly

The present invention relates to fluid transport circuits such as those used in motor vehicles, in particular to recirculate the exhaust gases of the combustion engines of these vehicles.

BACKGROUND OF THE INVENTION An exhaust gas recirculation circuit of the engine of a motor vehicle (commonly called EGR for "Exhaust Gas Recirculation") extends between the exhaust circuit and the intake circuit of the engine. thermal engine and conventionally comprises 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 valve regulator for regulating the flow rate of the gas stream in the recirculation circuit.

The structure of these recirculation circuits and the large number of parts that constitute them give them a large footprint and also complicate the manufacture. However, the available space in the engine compartment of the vehicle is increasingly restricted, making it difficult to implement current recirculation circuits. In addition, this restricted space limits the cooling possibilities of the components of the recirculation circuit which are subjected to the high temperature of the exhaust gas.

OBJECT OF THE INVENTION

An object of the invention is to provide a means for solving at least one of the aforementioned drawbacks.

SUMMARY OF THE INVENTION For this purpose, provision is made, according to the invention, of a valve assembly comprising a body defining at least one a first conduit and a valve mounted in the body and movable facing a seat formed in the first conduit, a connecting flange having a heat exchanger is fixed on the body, a flap being mounted in the flange for pivoting between a position connecting the first conduit to the exchanger and a bypass position in which the first conduit is not connected to the exchanger.

Thus, the valve assembly comprises a body with a movable valve and a flange for attaching the body to an exchanger. The flange not only provides this function of connecting the body with the exchanger, but also a support function of the flap. The valve assembly thus incorporates in a compact structure a valve, a flap and a flange for fixing the assembly on

1 exchanger.

Preferably, the body and the flange comprise seat surfaces for the flap when the flap is in at least one of its positions. Thus, the body and the flange both comprise seat surfaces for the flap, which limits the size of the flange and bring the body of the exchanger.

The invention also relates to a heat exchange device comprising an exchanger and such a valve assembly.

Other features and advantages of the invention will emerge on reading the following description of particular non-limiting embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

Reference will be made to the appended drawings, among which:

FIG. 1 is a perspective view of a heat exchanger associated with a valve assembly according to the invention, FIG. 2 is a view of this heat exchanger in section along the plane II of FIG. 1, the flap being in the position of connection of the valve assembly with the exchanger, FIG. 3 is a partial view, analogous to FIG. to that of Figure 2, showing the valve assembly when the flap is in a bypass position,

FIG. 4 is a partial exploded perspective 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 view similar to FIG. 6 of the body of the heat exchanger according to a second embodiment,

- Figure 8 is a view similar to that of Figure 6 of the body of the heat exchanger according to a third embodiment,

FIG. 9 is a view similar to that of 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. embodiment,

FIG. 11 is a partial cutaway view of the body of a heat exchanger with a particular profile of the channel separation partition,

FIG. 12 is a view similar to that of FIG. 6 of a heat exchanger body according to a fifth 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.

The heat exchanger 1 comprises a body generally designated 3, comprising an outer casing 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 so as to define with 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 with each other. 1 outside of 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, partitions 9 peripheral devices extend parallel to each other and 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 and 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 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 outer casing 4 are fixed independent fluid circuit defining members.

These members comprise two sealing elements 11, 12 fixed by welding at the ends of the central channel 7, respectively on the end side 4.1 and the end 4.2 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. L return element 13 makes it possible to send back a stream coming from some of the peripheral channels 10, in this case those identified 10. As it extends in the upper half of the outer envelope 4, towards the other peripheral channels 10, it is ie those identified 10.bs' extending into the lower half of the outer casing 4 (see more particularly Figures 5 and 6).

These members further comprise a connecting member of the ends of the peripheral channels 10, located on the side of the end 4.1, to fluid supply and discharge conduits. 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 mounted movable in the manifold 22 between an extreme position of closure and an extreme open position of the first conduit 24. The end portion 23 is provided 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 actuator 27, known per se, is arranged to slide in such a way that adjustable 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 for a gas flow in the valve assembly 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 envelope 4. The wings 31 are parallel to the walls 4.5, 4.6 of the outer casing 4 and are provided with bearings pivotally receiving an axis 32 of a double flap, generally designated 33, having two parts of flap 33.1, 33.2 s extending in the extension of one another on either side of the axis 32.

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 10b.

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 deviates a gas flow from the second conduit 28 directly to the first conduit 24 without passing through the heat exchanger 1 and a connection position (Figure 2) in which the flap 33 guides the gas flow from the second conduit 24 to the inlet opening 34 and outlet opening 35 to first conduit 24.

In the connection position, the side and end edges of the flap portion 33.1 are respectively pressed against seat surfaces 36, 37 extending into the manifold 22 and belonging to the valve body 21; the lateral and end edges of the flap portion 33.2 are in sealing engagement respectively against surfaces 38, 39 forming a seat and belonging to the flange 30. The surfaces 36, 37 extend on one side of the bearings opposite to the surfaces 38, 39. The flap 33 in connection position thus isolates the portion of the collector 22 into which the second duct 28 of the portion of the collector 23 into which the first duct 24 opens.

In the bypass position, the flap 33 deflects the gas flow directly to the first duct 24. As the inlet and the outlet of the exchanger open all two in the valve body behind the shutter, there is no circulation in the heat exchanger even if it is not sealed with respect to the conduits 24, 28. The surface 39 belongs to a crosspiece of the flange 30 which is integral with the shutter element 11 of the central channel 7.

Due to the structure of the flange 30 and the distribution of the surfaces 36, 37, 38, 39 forming the seat of the flap 33 between the valve body 21 and the flange 30, the flange 30 is compact and makes it possible to obtain a small distance between the valve body 21 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 perpendicularly to the axis 32 of the flap 33 and which comes be supported 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. It is possible to use any element or any shape that can form a thermal bridge between the valve body 21 and the body 3, for example one or more local increases in thickness. The return element 13 and the flange 30 comprise end-pieces 14, 15 intended to extend opposite the openings 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 carries the heat transfer fluid that will allow the cooling of the exhaust gas that will flow 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 direct heat transfer between them, and the peripheral partitions 9 provide a 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 allows to obtain a compact and efficient heat exchanger structure by favoring heat transfer by convection and conduction. In addition, a single central channel for the heat transfer fluid limits the lengths to be sealed and minimizes the risk of leakage.

It will further be noted that, since the shut-off element 11 is in contact with the coolant, the element promotes the cooling of the fin 29 and thus 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 10a extend from one side of the central channel 7 opposite the channels 10b. Figure 7).

According to a third embodiment, as represented 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 via a zigzag wall 112 reported in each peripheral channel 110. To create turbulence and increase the efficiency of the heat exchanger, these walls in zigzag 112 may have reliefs, for example embossing, to create turbulence in the gas stream.

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. One end of 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 member 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 branch channel 250 uncooled and an isolation channel 251 containing air and thermally isolating the bypass channel 250 of the central channel 207. The valve body 221 of the valve assembly 202 is attached to the body 203 of the exchanger by a flange 230 having a single flap 233 movable between a connection position of the duct 224 to the peripheral channels 210 and a bypass position in which the duct 224 is connected to the bypass channel 250.

Note 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 these and with the walls 4.5, 4.6 of the main channels 301 for the passage of the coolant. 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 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 structure different 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 of those 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 (in whole 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" within the meaning of the present description.

In Figure 3, we can see a first extruded part 3.A forming the envelope 4 and a second part 3.B delimiting the channels. Part 3.B comprises a central portion comprising the two central partitions 5 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 peripheral partitions 9.

Part 3.B is mounted in part 3.A in such a way 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 longitudinal edges of the peripheral partitions 9 to 1 envelope 4, a sealing of the peripheral channels 9 relative to each other is not necessary for the proper operation of the exchanger 1. In contrast, the central channel 7 is longitudinally waterproof him even before the assembly of part 4.8 in part 4.A, the risk of leakage of the coolant to be avoided.

It will be noted that ribs 70 project from peripheral partitions to increase the exchange surfaces with the gas flow.

In FIG. 14, two identical extruded parts can be seen forming half-bodies 3.A ¹ , 3.B 'each delimiting: 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 ¹ , 3.B 'are joined to form the central channel 7 and are connected to one another by a longitudinal weld extending along the walls 4.3 and 4.4.

Moreover, other sounding methods than the laser sounding 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 cause 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 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 surfaces forming a seat belonging to the valve body 21 and the flange 30 by a distance less than a minimum clearance clearance. This means that there is no impervious support of the flap on these surfaces but that a space extends between them, this space being of sufficiently small dimensions so that the resulting leakage is 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 and / or the flange.

The fin 29 is optional.

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.

Claims

1. Valve assembly, comprising a body (21) delimiting at least a first duct (24) and a valve (26) mounted in the body and movable facing a seat (25) formed in the first duct, characterized in that a flange (30) for connection to a heat exchanger (1) is fixed to the body, a flap (33) being mounted in the flange for pivoting between a connection position of the first duct to the exchanger and a position bypass in which the first conduit is not connected to the exchanger.

2. The assembly of claim 1, wherein the valve body (21) and the flange (30) comprise surfaces (36, 37, 38, 39) forming a seat for the flap (33) when it is in the least one of his positions.

3. An assembly according to claim 2, wherein the flap (33) in said at least one of its positions bears against the surfaces (36, 37, 38, 39) forming a seat.

4. The assembly of claim 2, wherein the flap (33) in said at least one of its positions is spaced from the seat surfaces of a set of low leakage.

5. An assembly according to claim 2, 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, 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).

6. The assembly of claim 2, wherein the surfaces (36, 37, 38, 39) forming the seat of the body (21) and the flange (30) cooperate with the flap (33) when it is in its position. connection.

7. An assembly according to claim 1, delimiting a second duct (28), the first duct (24) and the second duct forming an inlet duct and an outlet duct of the valve assembly, and the flange () defining an inlet opening (34) and an outlet opening (35) of the exchanger (1), the flap (33) in the connecting position putting in communication the inlet duct and the outlet duct of the assembly valve with the inlet duct and the outlet duct of the exchanger respectively and the shutter in bypass position putting the inlet duct of the valve assembly in communication directly with the outlet duct of the set of valve.

The valve assembly of claim 7, wherein the second conduit (28) is delimited by the valve body (21).

The valve assembly of claim 1, wherein the flange (30) is thermally conductive and is arranged to form a thermal bridge between the valve body (21) and the exchanger (1).

10. Heat exchange device comprising an exchanger (1) and a valve assembly (2) according to any one of the preceding claims.