EP1636533B1 - Heat exchanger comprising a casing and a bundle which are made from aluminium sheet and which are brazed together - Google Patents

Abstract

The invention relates to a heat exchanger comprising a heat exchanger bundle (14) consisting of a stack of embossed plates (28) which define therebetween first circulation channels for the circulation of a gas to be cooled and second circulation channels for the circulation of a liquid to be cooled. Moreover, the aforementioned bundle (14) is housed in a casing (4, 6). The inventive exchanger includes play compensation means between the bundle (14) and the casing, said means comprising a regulating wedge (5) which is disposed between said bundle and casing. The regulating wedge is equipped with a base (52) and two raised edges (54) which clasp the bundle (14).

Description

The invention relates to heat exchangers, and more particularly to plate heat exchangers for motor vehicles, for example charge air coolers.

It relates more particularly to a heat exchanger comprising a heat exchange bundle consisting of a stack of stamped plates which define between them first circulation channels for the circulation of a gas to be cooled and second circulation channels for circulation. a coolant, the beam being housed in a housing.

In an exchanger of this type, the plates are assembled by soldering, which results in a variation in the height of the stack of the plates, variation inherent to the assembly method used. Consequently, it is not possible, as in the case of a bundle consisting of tubes, to mount a collector adapted to receive a seal and a molded plastic or aluminum box.

In order to solve this difficulty, it is known ( DE 199 02 504 and JP 102 38 969 ) housing the heat exchange bundle inside a molded plastic or aluminum housing having fluid inlet and outlet nozzles and closing the housing with a welded or crimped lid.

A heat exchanger for a motor vehicle comprising a heat exchange bundle constituted by a stack of plates and housed in a housing, comprising spacers allowing a clearance clearance between the beam and the housing, is known from the document DE 29 03 543 A .

To resist the pressure of the gas to be cooled, which can reach several bars and avoid any deformation of the housing walls likely to create air leaks, the housing must be reinforced especially if it is plastic. This problem is all the more crucial as the volume subjected to the pressure of the gas is important. The strengthening of the housing leads to a penalizing congestion.

It is also known to weld aluminum boxes molded onto the bundle by the TIG welding process or to glue a box molded on the envelope surrounding the bundle. TIG welding of an aluminum foundry box on the bundle is not a design suitable for large series due to weight and cost. As regards the bonding of a molded box on the envelope which surrounds the beam, the peripheral zone necessary for mounting the box can be disadvantageous from the point of view of space, especially when the dimensional constraints are severe.

The present invention specifically relates to a heat exchanger that overcomes these disadvantages. The heat exchanger comprises means for catching a clearance between the beam and the housing. In a preferred embodiment, the catching means are constituted by a catch-up wedge disposed between the beam and the housing.

Thanks to the presence of these catching means, the heat exchange beam is held in abutment by two faces against two inner walls of the housing. As a result, the housing can be assembled by soldering on the beam on these two faces, which has the effect of stiffening it and giving it good pressure resistance.

The housing consists of two half-shells each having a bottom wall and a rim consisting of side wall, the side walls of a half-shell sliding relative to the side walls of the other half-shell.

With this feature, the two parts that make up the housing can move relative to each other so as to adapt to the height of the beam of so that the lower face of the housing is in contact with the bottom of the lower half-shell, while the upper face of the heat exchange bundle is in contact with the bottom wall of the upper half-shell. It is therefore possible to braze together the beam with each of the two bottom walls of the upper half-shell and the lower half-shell.

In total, the beam is brazed to the housing by four of its faces so that the walls of the housing are held rigidly and can not deviate from the beam. This prevents the appearance of gas leaks. The exchanger made thus allows to retain the advantages of an aluminum design, namely a small footprint, a good resistance to pressure and temperature. In addition, since the exchanger is made of a single material, it is easily recyclable. '

Advantageously, the sliding of the two half-shells takes place in a direction perpendicular to the plane of the plates of the heat exchange bundle. In other words, the joint plane of the two half-shells is parallel to the plane of the plates. However, it goes without saying that this characteristic is not imperative and that other achievements can be envisaged. It is also conceivable that the joint plane between the two half-shells is inclined relative to the plates of the heat exchange bundle. This feature allows to leave more room for the implantation of the inlet and outlet pipes of the gas to be cooled.

In a particular embodiment, the take-up wedge has a general U-shape comprising a bottom wall disposed between the heat exchange bundle and the housing and two raised edges which take place on either side of the exchange bundle. heat.

This embodiment is advantageous because the raised edges make it possible to seal gas leaks that could occur between the heat exchange zone of the beam and the inner wall of the housing.

Advantageously, the raised edges are clipped onto the heat exchange bundle.

Advantageously, the bottom wall of the catch-up shim has corrugations. These corrugations give it elasticity, which allows the absorption of play between the beam and the housing.

Preferably, the catch-up wedge, and particularly the bottom wall, comprise bevelled edges. These beveled edges facilitate the insertion of the catch between the beam and the housing.

Finally, in an advantageous embodiment, the housing is larger than the heat exchange bundle on either side of the faces to which it is not soldered so as to clear free spaces which form a collecting box. inlet and an outlet manifold for a gas.

According to yet another characteristic of the invention, the beam is brazed on four sides to the housing.

• la figure 1 est une vue extérieure en perspective d'un échangeur de chaleur conforme à la présente invention ;
• la figure 2 est une vue en coupe selon le plan de coupe II-II de la figure 1 ;
• la figure 3 est une vue éclatée en perspective de l'échangeur de chaleur représenté sur les figures 1 et 2 ;
• la figure 4 est une vue de détail en coupe qui illustre la réalisation du faisceau d'échange de chaleur ;
• la figure 5 est une vue en coupe selon la ligne V-V de la figure 2 ; et
• la figure 6 est une vue extérieure en perspective d'un second mode de réalisation d'un échangeur conforme à la présente invention.

Other features and advantages of the present invention will become apparent upon reading the following description of exemplary embodiments given by way of illustration with reference to the appended figures. In these figures:

• the figure 1 is an external perspective view of a heat exchanger according to the present invention;
• the figure 2 is a sectional view along the section plane II-II of the figure 1 ;
• the figure 3 is an exploded view in perspective of the heat exchanger shown on the Figures 1 and 2 ;
• the figure 4 is a sectional detail view illustrating the realization of the heat exchange bundle;
• the figure 5 is a sectional view along line VV of the figure 2 ; and
• the figure 6 is an external perspective view of a second embodiment of an exchanger according to the present invention.

The figure 1 is an external perspective view of a heat exchanger according to the present invention, a charge air cooler in the example shown. It comprises a housing consisting of two half-shells, namely a lower half-shell 4 and an upper half-shell 6 connected along a joint plane 7.

The lower half-shell 4 has a generally flat bottom wall 8 of square or rectangular shape and four side walls 9 connected to the bottom wall 8 and substantially perpendicular to the latter. The upper half-shell 6 comprises a generally flat bottom wall 10 of rectangular or square shape and four side walls 11 connected to the bottom wall 10 and substantially perpendicular to it. In addition; the side walls 11 terminate in an enlarged part 13 ( figure 2 ) which allows the reception, with sliding, side walls 9 of the lower half-shell 4. The length of the enlarged portion 13 is provided long enough to allow the half-shells 4 and 6 to adapt to variations in height of the heat exchange beam 14 (see figure 5 ) that they contain. An inlet manifold 16 of the charge air is provided on the lower half-shell 4 and an outlet manifold 18 of the charge air is provided on the upper half-shell 6. As can be seen in particular in FIG. figure 2 , the charge air enters the exchanger through the inlet pipe 16, as shown by the arrow 17. It reaches in an inlet air box 20 and then passes through the heat exchange bundle 14 whose structure will be described in more detail later by exchanging heat with a cooling fluid. After having passed through the heat exchange bundle 14, the cooled supercharging air arrives in an outlet air box 22, then leaves the charge air cooler through the manifold 18, as shown by the arrow 19.

In the example shown, the inlet pipe 16 is made of aluminum sheet. It is attached to the lower half-shell 4. On the contrary, the outlet pipe 18 is made of plastic material and is brazed together, in a single operation, at the same time as the entire heat exchanger in a furnace. brazing.

An inlet pipe 23, and an outlet pipe 25 of the cooling liquid, in general the cooling water of the engine of the motor vehicle, are provided on the upper wall of the half-shell 6. In the example, the inlet and outlet pipes 23 and 25 are made of aluminum and they are soldered to the upper half-shell. The coolant enters the heat exchange bundle through the inlet manifold 23 as schematized by the arrow 24, traverses the heat exchange bundle 14 by exchanging heat with the charge air, and then returns by the outlet pipe 25 as shown schematically by the arrow 26.

The heat exchange bundle 14 ( figure 3 ) is constituted by a stack of plates 28 between which corrugated spacers 29 are arranged which improve the heat exchange between the charge air and the plates. Each plate 28 has a substantially rectangular shape with two small sides 28a and two long sides 28b. Each plate 28 has a bottom wall 31 limited by a peripheral flange 32. Ribs 33 are provided in the bottom wall 31 of each of the plates to delimiting circulation passes for the coolant.

The bottom wall 31 and the peripheral rim 32 define a shallow bowl. As can be seen more particularly on the figure 4 , the plates 28 are grouped in pairs assembled by their peripheral rim 32. In this way, the bowl of the upper plate and the bowl of the lower plate belonging to the same pair of plates are added to form a channel 34 for circulation of the cooling fluid. Furthermore, two bosses 36 are formed along a small side 28a of each of the plates 28. The bottom of each boss has a circulation passage 27 for the cooling fluid. The bosses of a pair of plates are supported on the bosses of adjacent pairs of plates. Thus, an inlet manifold and an outlet manifold (on the figure 4 the inlet manifold 38) is shown for the cooling fluid. The cooling fluid enters the beam as shown schematically by the arrow 24 and then circulates in the circulation channels 34 as shown schematically by the arrows 39. The output of the fluid out of the heat exchange bundle 14 is in the opposite direction.

The bosses 36 of two pairs of plates also determine between them circulation channels 41 for the gas to be cooled, the supercharging air in the example described. The corrugated spacers 29 disposed in the circulation passages 41 improve the heat exchange. They are in the form of corrugated inserts that extend to the boss 36. There is, therefore, between the side walls 9, 11 of the lower half shell 4 and the upper half shell 6 located along the small side 28a of the heat exchange bundle in which are arranged the bosses 36 passages 43 which directly communicate the inlet air box 20 and the outlet air box 22 without the charge air passes through the heat exchange surface materialized by the turbulator generators 29. the passages 43 thus constitute leaks detrimental to the proper functioning of the exchanger.

We have shown on the figure 3 an exploded view in perspective of the exchanger represented on the Figures 1 to 5 . Note in particular in this figure the presence of means of catching a game between the heat exchange beam 14 and the side walls 9 and 11 of the lower half-shell and the upper half-shell. In the example, the catch-up means are constituted by a catch-up wedge 50 disposed between the heat exchange bundle 14 and an inner wall of the housing. Advantageously, as will be explained later, the catch-up wedge is disposed between the short side 28a of the plates 28 along which the bosses 36 are arranged (not visible on the figure 3 ) and the inner wall of the housing located opposite these small sides 28a of the plates.

In the example, the catch 50 has a generally flat bottom wall 52 and two raised edges 54 substantially perpendicular to the bottom wall 52 and located at each end thereof. Thus, the catch 50 has in section the shape of a very elongated U. The raised edges take place on either side of the long sides 28b of the plates 28 of the heat exchange bundle 14. The bottom wall 50 has corrugations 56 whose function is to give it elasticity. In addition, the shim 50 has beveled edges 58 at its upper part and at its lower part. The beveled edges 58 serve to facilitate the insertion of the catch-up wedge between the end of the heat exchange bundle 14 and the front wall of the housing. The raised edges 54 comprise fastening means which make it possible to hold them on the heat-exchange bundle 14. In the example described, the catch-up wedge 50 is clipped onto the bundle. The raised edges 54 have projections 60 made by stamping and directed towards the heat exchange bundle. The projections 60 are housed in housing (not shown) provided in the beam to receive them.

Thanks to the presence of the catch 50, the short sides 28a of the plates of the heat exchange bundle are firmly pressed against the inner walls of the lower half-shell 4 and the upper half-shell 6. As a result, when the exchanger is brazed, the side walls 9 and 11 of the lower and upper half-shells 4 and 6 are secured to the bundle 14 so that they can not deviate from the latter under the effect of the pressure of the supercharging air, which can reach several bars.

In addition, as explained above, the lower half-shell and the upper half-shell can slide freely relative to each other a sufficient distance to allow adjustment to changes in height of the stack. plates 28. Thus, the lower plate of the heat exchange bundle rests on the bottom wall 8 of the lower half-shell 4 and further, the bottom wall 10 of the upper half-shell 6 comes to apply. against the upper plate 28 of the heat exchange bundle 14. At the time of the brazing operation, the bottom walls 8 and 10 are thus brazed together respectively to the lower plate and to the upper plate of the exchange bundle. 14. The combination of this arrangement with the one above makes it possible to assemble four of the six faces of the housing to the heat exchange beam by soldering so that these four faces which surround the exchange beam of c. hauler 14 can not deviate from him. This prevents the appearance of air leakage to cool.

Thanks to all these features, a compact heat exchanger is made, since the thickness of the two half-shells is small. Its cost is low because it is assembled in a single operation by a simple assembly process. It ensures a good resistance to temperature and the pressure. And in addition, as explained previously, it is easily recyclable.

As explained above, the adjustment wedge 50 is advantageously arranged along the short side 28a of the plates along which the bosses 36 are formed, the stack of which forms the inlet and outlet collectors of the cooling fluid. Indeed, the raised edges 54 are designed to have a length sufficient to close the leakage passages 43 located between the end of the corrugated inserts 29 and the side walls 9 and 11 of the two half shells. In other words, the upstanding edges 54 must be sufficiently long to partially cover the end of the corrugated tabs 29. Thus, the raised edges 54 allow the leakage passages 43 to be closed completely so that the overall thermal efficiency of the the exchanger is improved, which is another advantage of the exchanger according to the invention.

In the embodiment described with reference to Figures 1 to 5 , the joint plane 7 between the two half-shells 4 and 6 is parallel to the plane of the plates 28 of the heat exchange bundle 14. However, this characteristic is not imperative and it is shown on the figure 6 an alternative embodiment of the two half-shells 4 and 6 in which the joint plane 64 is arranged obliquely with respect to the plane of the plates 28. For example, the joint plane 64 may be arranged substantially diagonally with respect to the walls of ends 65. The inclination of the joint plane 64 is intended to clear enlarged spaces 66 and 68 on the lower half shell 4 and the upper half shell 6 respectively. The enlarged spaces make it possible to facilitate the implantation of the inlet pipe 60 and the outlet pipe (not visible on the figure 6 ) air to cool.

Claims (13)

1. Heat exchanger comprising a heat exchange bundle (14) consisting of a stack of pressed plates (28) which between them define first flow passages (41) for the flow of a gas that is to be cooled and second flow passages (34) for the flow of a cooling liquid, the bundle (14) being housed in a casing (4, 6), characterized in that the said exchanger comprises means (50) for compensating for clearance between the bundle (14) and the casing (4, 6), and in that the casing is made of two half-shells (4, 6), each of the half-shells comprising an end wall (8, 10) and side walls (9, 11), and in that the said compensating means (50) allow the sides of the plates of the heat exchange bundle to be pressed firmly against the interior walls of the lower half-shell (4) and of the upper half-shell (6) in such a way that, when the exchanger is brazed, the side walls (9; 11) of the lower (4) and upper (6) half-shells become secured to the bundle (14).
2. Heat exchanger according to Claim 1, characterized in that the compensating means consist of a compensating packing piece (50) positioned between the bundle (14) and the casing (4, 6).
3. Heat exchanger according to Claim 1 or 2, characterized in that the side walls (9) of one half-shell (4) slide relative to the side walls (11) of the other half-shell (6).
4. Heat exchanger according to Claim 3, characterized in that the joining plane (7) of the two half-shells (4, 6) is parallel to the plane of the plates (28) of the heat exchange bundle (14).
5. Heat exchanger according to Claim 3, characterized in that the joining plane (64) where the two half-shells (4, 6) meet is inclined with respect to the plane of the plates (28) of the heat exchange bundle.
6. Heat exchanger according to one of Claims 3 to 5, characterized in that the compensating packing piece (50) is in the overall shape of a U having an end wall (52) positioned between the bundle (14) and the casing (4, 6) and two turned-up edges (54) which lie one on each side of the heat exchange bundle (14).
7. Heat exchanger according to Claim 6, characterized in that the compensating packing piece (50) is positioned along the short sides (28a) of the plates (28), along which sides there are formed bosses (36) the superposing of which creates an inlet or outlet header (38) for the cooling fluid.
8. Heat exchanger according to one of Claims 6 and 7, characterized in that the turned-up edges (54) are clipped to the heat exchange bundle (14).
9. Heat exchanger according to Claim 8, characterized in that the turned-up edges (54) have projections (60) which fit into corresponding housings belonging to the heat exchange bundle (14).
10. Heat exchanger according to one of Claims 6 to 9, characterized in that the end wall (50) has corrugations (56).
11. Heat exchanger according to Claim 10, characterized in that the corrugations (56) of the end wall (52) of the compensating packing piece have chamfered edges (58).
12. Heat exchanger according to one of Claims 1 to 11, characterized in that the casing (4, 6) is larger than the heat exchange bundle (14) on each side of the faces (28b) to which it is not attached by brazing so as to leave empty spaces (20, 22) which form an inlet header box (20) and an outlet header box (22) for a gas.
13. Heat exchanger according to one of Claims 1 to 12, characterized in that the bundle (14) is brazed to the casing (4, 6) along four faces.

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