HEAT EXCHANGER, IN PARTICULAR A SUPERCHARGING AIR COOLER

Abstract

A heat exchanger is disclosed. The heat exchanger has a heat exchange assembly which defines first circulation channels for the circulation of a gas to be cooled and second circulation channels for the circulation of a cooling liquid, and two gas intake and gas outlet collectors, respectively, which are assembled on two open faces of the heat exchange assembly, respectively, in which the first circulation channels open. A first collector is crimped to the heat exchange assembly and a second collector is soldered or welded to the heat exchange assembly.

Description

The invention relates to the field of heat exchangers, in particular for motor vehicles.

It relates more particularly to a heat exchanger which comprises a thermal exchange assembly which determines first circulation channels for the circulation of a gas to be cooled and second circulation channels for the circulation of a cooling liquid.

Such a heat exchanger can be produced in particular in the form of a supercharging air cooler of a thermal engine of a motor vehicle, the gas to be cooled being constituted by the supercharging air of the engine.

This is because thermal engines which are supercharged or turbo-compressed, in particular diesel engines, are supplied with compressed air which is called supercharging air from a turbo-compressor which is activated by the exhaust gases of the engine.

However, this compression has the effect of heating the air which is at an excessively high temperature and it is desirable, for correct operation of the engine, to cool it in order to reduce the temperature thereof before it is introduced into the cylinders of the engine.

To this end, a heat exchanger which is called a supercharging air cooler is conventionally used.

This cooler has the function of cooling the supercharging air by means of heat exchange with another fluid, such as external air, or a liquid, such as the water of the cooling circuit of the engine, thus forming an exchanger of the air/air or liquid/air type.

In known manner, a heat exchanger, and more specifically a supercharging air cooler, comprises heat exchange elements and fluid flow elements in which fluids which mutually exchange heat flow.

Numerous associations of fluids may be envisaged, whether liquids and/or gases be involved.

Numerous structural configurations may be envisaged.

There are known exchangers which comprise a heat exchange assembly comprising a stack of plates which are arranged parallel with each other in one or more mutually parallel rows, these plates being arranged to define, on the one hand, first circulation channels for a first fluid and, on the other hand, second circulation channels for a second fluid by exchanging heat with the first fluid.

These plates may alternate with elements for disturbing the flow of a fluid, for example, a gaseous fluid, such as the supercharging air.

According to a known solution, an exchanger comprises an intake collection box and an outlet collection box, for the gaseous fluid, such as the supercharging air, which boxes are arranged at one side and the other of the assembly.

These collection boxes enable the supercharging air to be introduced and discharged through the exchanger.

Furthermore, in the case of a cooler of the liquid/air type, it may be fitted in a selected location of the engine compartment, in particular close to the engine. To this end, the outlet box may be assembled with the cylinder head of the engine, either directly or by means of an intermediate element, and ensures in particular the function of introducing supercharging air toward each of the cylinders of the engine.

Such an exchanger is mechanically loaded, in particular in the region of the fixings to the engine cylinder head.

Furthermore, in the case of a supercharging air cooler, the outlet collector for the introduction of supercharging air toward the cylinders of the engine may enable provision of a mixture which comprises the air cooled by the exchanger and a portion of the exhaust gases from the engine, called recirculated exhaust gases. To this end, a valve enables a portion of the recirculated exhaust gases to be injected into a space defined by the gas outlet collector, called the gas intake outlet collector.

In this instance, the gas intake outlet collector has to be capable of maintaining the high temperatures of the exhaust gases from the engine.

An object of the invention is in particular to provide at lower cost a heat exchanger which is capable of adapting to the mechanical stresses and to the temperature conditions at the side of the gas intake and the side of the gas outlet.

An object of the invention is also to provide such a heat exchanger which is most particularly suitable as a supercharging air cooler.

To this end, the invention proposes a heat exchanger comprising:

a heat exchange assembly which defines first circulation channels for the circulation of a gas to be cooled and second circulation channels for the circulation of a cooling liquid, andtwo gas intake and gas outlet collectors, respectively, which are assembled on two open faces of the heat exchange assembly, respectively, in which the first circulation channels open,characterized in that a first collector is crimped to the heat exchange assembly and the second collector is soldered or welded to the heat exchange assembly.

In this manner, the assembly technology of the two collectors and their material may be adapted independently in accordance with the application and the operating conditions in order to comply in particular with the mechanical stresses and/or the temperature conditions. Furthermore, this adaptation enables costs to be reduced.

According to a preferred embodiment, the gas intake collector is crimped to the heat exchange assembly and the gas outlet collector is welded or soldered to the heat exchange assembly. In this manner, the gas outlet collector, for example, fixed to the cylinder head of the engine, can be soldered or welded to the heat exchange assembly in order to comply with the mechanical stresses independently of the fixing and the material of the intake collector.

Advantageously, the first collector which is crimped to the heat exchange assembly is produced from a plastics material or a metal material, such as an aluminum alloy.

The second collector which is soldered or welded to the heat exchange assembly may be produced from a metal material, such as an aluminum alloy.

In this manner, the material and the technology for assembly with the heat exchange assembly may be adapted independently for the two collectors in accordance with the operating conditions of the heat exchanger and, on the one hand, in the region of the gas intake and, on the other hand, in the region of the gas outlet.

The collectors may be produced by means of molding in accordance with the selected shape.

The two collectors are advantageously assembled on two opposing faces of the assembly, respectively.

According to an aspect of the invention, the first collector which is crimped to the heat exchange assembly comprises a collector casing and a collection plate in which the first channels of the heat exchange assembly open, and the collector casing has an open face which is delimited by a peripheral rim which is held by means of crimping against the collection plate.

According to an embodiment, the collection plate is generally in the form of a frame and comprises a generally rectangular peripheral edge which delimits a gas passage opening and which has a crimping rim which surrounds a recess for receiving the peripheral rim of the first collector which is crimped to the heat exchange assembly.

In a preferred application of the invention, the heat exchanger is produced in the form of a supercharging air cooler of a thermal engine of a motor vehicle, the first circulation channels serving to circulate the air to be cooled.

The gas intake collector may comprise a tube which is integrally molded, and the gas outlet collector has a supercharging air intake opening for the thermal engine of the vehicle. The gas outlet collector forms an air intake diffuser for the thermal engine of the vehicle. In this case the supercharging air cooler is connected to the air intake diffuser of the engine.

According to one embodiment, the gas outlet collector defines a gas collection space in which the first circulation channels open, and comprises an injection channel for recirculated exhaust gases, and a plurality of injection holes for recirculated exhaust gases for the injection of recirculated exhaust gases into the gas collection space of the gas outlet collector.

The gas outlet collector may comprise an intake valve for the recirculated exhaust gases into the gas outlet collector.

Other features and advantages of the invention will be appreciated more clearly from a reading of the following description, given by way of illustration and non-limiting example, and the appended drawings, in which:

FIG. 1 is a perspective view of a heat exchanger according to a first embodiment of the invention;

FIG. 2 is a perspective view of the assembly of the heat exchanger of FIG. 1;

FIG. 3 is a sectioned view along line of FIG. 2;

FIG. 4 is a sectioned view along line IV-IV of FIG. 2;

FIG. 5 is a sectioned view along line V-V of FIG. 2;

FIG. 6 is a perspective view showing the assembly of FIG. 2 before assembly of the collectors;

FIG. 7 is a perspective view of a heat exchanger according to a second embodiment, and

FIG. 8 is a perspective view of the heat exchanger of FIG. 7 whose outlet collector for supplying the thermal engine with intake gas comprises a device for injection of recirculated exhaust gases into the outlet collector.

In these Figures, elements which are substantially identical have the same reference numerals.

The invention relates to a heat exchanger 1, in particular for cooling the supercharging air for a thermal engine, such as a motor vehicle diesel engine.

FIG. 1 shows a first embodiment of the heat exchanger 1.

Such an exchanger 1 may be an exchanger which is called an “air/liquid” exchanger, that is to say, an exchanger in which the fluids which exchange heat are air and a liquid such as water. In the case of a cooler of supercharging air, the liquid is preferably water of the “low-temperature” cooling circuit of the engine; it is typically glycol water.

Of course, the invention is not limited to the supercharging air coolers of motor vehicles and can be used for other types of heat exchanger.

The heat exchanger 1 illustrated in FIG. 1 comprises a heat exchange assembly 10 for heat exchange which, in the example, is formed by an assembly of stacked plates, as will be described below. The heat exchange assembly 10 is provided with two tubes 12 and 14 which serve, for example, to introduce and to discharge the cooling liquid, respectively.

The heat exchange assembly 10 is surrounded, on the one hand, by a gas intake collector 16 which is provided with a gas intake tube 20 and, on the other hand, by a gas outlet collector 18.

The two gas intake and gas outlet collectors 16, 18 are in the example illustrated assembled on two opposing faces of the heat exchange assembly, respectively.

The gas outlet collector 18 is also called an air intake diffuser for the thermal engine of the vehicle. This gas outlet collector 18 may be fixed directly or indirectly to the cylinder head of the engine. Such a gas outlet collector 18 is also called a gas intake collector 18.

The collectors 16 and 18 and the tube 20 may be produced by means of molding in the desired shape and are assembled at one side and the other of the heat exchange assembly 10.

At least one collector, in this instance the collector 16, may be assembled with the heat exchange assembly 10 via a collection plate 24.

Reference will now be made to FIGS. 2 to 5 to describe the structure of the heat exchange assembly 10.

In the example illustrated, the heat exchange assembly 10 is formed by an assembly of drawn plates 28 which are also called semi-plates, in accordance with a known technique. However, the invention can also be used for other types of assembly, and in particular for assemblies which comprise tubes and fins.

As shown in FIG. 2, the heat exchange assembly 10 is formed by a stack of drawn plates 28, 28A, 28B which are arranged in pairs and which are produced in an identical manner, with the exception of two opposing end plates 28A and 28B; one of the end plates, for example, the plate 28A, receiving the tubes 12 and 14 mentioned above.

Each of the drawn plates 28, 28A, 28B has according to the example illustrated a generally substantially rectangular shape with two opposing long sides and two opposing short sides.

A plate 28, 28A, 28B comprises, for example, a substantially planar base wall 30 which is delimited by a generally rectangular peripheral rim 32 which is raised relative to the base wall 30 in order to form a shallow bowl.

Furthermore, each of the plates 28, 28A, 28B may comprise two end protrusions 34, 34A, 34B and 36, 36A, 36B.

The protrusions 34 and 36 of the intermediate plates 28 are provided with respective circular openings 38 and 40 (FIG. 5).

The protrusions 34A and 36A of the end plate 28A are different and the protrusions 34 and 36 of the intermediate plates 28 and have respective openings 38A and 40A which are capable of receiving respective tubes 14 and 16. In the same manner, the other end plate 28B has different protrusions 3413 and 36B since they each comprise a closed wall which therefore does not have any opening.

As can be seen more particularly in FIGS. 3 and 4, the drawn plates 28, 28A, 28B are arranged in pairs and the respective protrusions 34, 36 of a plate 28 belonging to a pair are in communication with the respective protrusions 34, 36 of an adjacent plate 28 which belongs to a pair of adjacent plates. This allows a fluid communication to be established between the chambers which the respective pairs of plates delimit.

In the example illustrated in FIG. 5, the plates 28, 28A, 28B are symmetrical and their respective protrusions 34, 36, 34A, 36A form collars which enable mutual self-centering of the plates 28, 28A, 28B in order to ensure good assembly by means of soldering.

The heat exchange assembly 10 may further comprise undulating inserts 42 (FIG. 3) which are arranged in each case between adjacent pairs of plates. These undulating inserts 42 have their respective undulations soldered to the respective base walls 30 of two facing plates 28, 28A, 28B.

With reference to FIG. 2 again, the respective peripheral rims 32 of two plates 28, 28A, 28B which belong to the same pair are, for example, welded over the entire periphery thereof to define channels or plates for circulation of the cooling liquid, which communicate with each other via the respective protrusions.

Furthermore, the short sides of the plates 28, 28A, 28B may have an edge 44 which is folded in the form of a U, which allows the pairs of plates 28 to be assembled together, delimiting circulation channels for the gas to be cooled. The edges 44 are surrounded by an oval in FIG. 3.

In this manner, the heat exchange assembly 10 delimits first channels 46 for the gas to be cooled, in which the undulating inserts 42 can be arranged, and second channels 48 for the circulation of the cooling liquid (FIGS. 3 and 4).

As a result of the fact that the edges 44 of the plates are connected, there is thus defined for the gas to be cooled a gas stream which extends at the same time through all of the first channels 46 in order to be cooled by the cooling liquid which circulates in the second channels 48.

As can be seen in FIG. 4, clips 45 may be formed on the peripheral rim 32 of the plates 28, 28A, 28B in order to enable temporary assembly of the plates of each pair before they are definitively assembled by means of soldering.

Furthermore, the plates 28, 28A, 28B may have respectively on their base wall 30 a rib 50 which extends parallel with the long sides of the plate 28, 28A, 28B over a length smaller than that of a long side, in order to define a U-shaped circulation path in each second channel 48 (FIG. 2).

All of the elements of the heat exchange assembly 10, that is to say, the drawn plates 28, 28A, 28B, the undulating inserts 42, the intake and outlet tubes 12, 14 of the cooling liquid are advantageously produced from an aluminum alloy, assembled together and then soldered in a single operation in a soldering oven.

Furthermore, as can be seen in FIG. 2, the heat exchange assembly 10 comprises two opposing open faces: an open face 52 at the side of the gas intake and an open face 54 at the side of the gas outlet.

The first channels 46 open at the same time in the two above-mentioned faces 52 and 54.

The collectors 16 and 18 are assembled on the open faces 52 and 54, respectively, as can be seen in FIG. 1.

In this manner, with reference to FIGS. 1 and 3, the gas to be cooled is introduced into the gas intake collector 16 through the tube 20, then passes through the first circulation channels 46 of the heat exchange assembly 10 in order to reach the gas outlet collector 18 and to leave it to be introduced into the cylinders of the engine (not illustrated). The gas is cooled by a cooling liquid which is introduced into the heat exchange assembly 10 via the tube 12, flows in the second channels 48 of the heat exchange assembly 10 in order to exchange heat with the gas to be cooled and then leaves the assembly via the tube 14.

With regard to the intake and outlet collectors 16, 18, they are assembled with the heat exchange assembly 10 in accordance with different technologies.

More specifically, a first collector may be assembled by means of crimping whilst the second collector is assembled by means of soldering or welding to the heat exchange assembly 10.

By way of example, the gas intake collector 16 is assembled with the heat exchange assembly 10 by means of crimping via the collection plate 24. To this end, the collector 16 has a collection casing 161 which is assembled with the collection plate 24 by means of crimping.

The casing 161 of the air intake collector 16 which is, for example, capable of being crimped to the collection plate 24 may be produced from plastics material, or another appropriate material, for example, of a metal alloy such as an aluminum alloy.

The collection plate 24 is, for example, soldered to the heat exchange assembly 10. To this end, the collection plate 24 may be produced from an aluminum alloy, and assembled with the elements of the heat exchange assembly 10, and soldered to the heat exchange assembly 10 in a single operation in a soldering oven.

The collection plate 24 may be produced in the form of a generally rectangular frame. More specifically, in accordance with the example illustrated, the collection plate 24 comprises a generally rectangular peripheral edge 56 which delimits a gas passage opening 58 opposite the open face 52 of the heat exchange assembly 20 at the side of the gas intake.

Furthermore, the collection plate 24 may comprise a covered portion 60 (cf. FIG. 6) in order to prevent the passage of the gas into an end region of the heat exchange assembly 10 which does not have any first channels 46. This end region corresponds to the portion of the heat exchange assembly 10 which does not have any undulating inserts 42 and which comprises protrusions 34, 36, 34A, 36A, 34B, 36B. In this manner, the gas to be cooled is channeled into the useful portion of the heat exchange assembly 10, that is to say, the portion which corresponds to the first channels 46 and which comprises, for example, undulating inserts 42.

The peripheral edge 56 of the collection plate 24 has, for example, at the side facing the heat exchange assembly 10, a rim 62 in the form of a shoulder for receiving the open face 52 of the heat exchange assembly 10.

The rim 62 in the form of a shoulder is shaped to enable the collection plate 24 to be fitted with the heat exchange assembly 10 with compression, which enables a retention tool for the soldering to be dispensed with.

As set out above, the intake collector 16 may be assembled by means of crimping with the heat exchange assembly.

To this end, the peripheral edge 56 of the collection plate 24 at the opposing side which does not face the heat exchange assembly 10 may comprise a crimping rim 64 which surrounds a recess (which cannot be seen in the Figures) for receiving a peripheral rim 68 of the casing 161 of the collector 16. The peripheral rim 68 of the casing 161 of the collector 16 can thus be received in the recess of the collection plate 24 and be crimped by the crimping rim 64. This crimping rim 64 may be constituted in conventional manner by a serrated rim with foldable tongues, by an undulating rim. Other construction variants of the crimping rim may be envisaged.

With reference again to FIG. 1, the gas outlet collector 18 according to a first embodiment may be produced in the form of a flange or frame which is generally of substantially rectangular form.

The gas outlet collector 18 is, for example, soldered to the heat exchange assembly 10. To this end, the gas outlet collector 18 may be produced from an aluminum alloy and assembled with the elements of the heat exchange assembly 10 and soldered to the heat exchange assembly 10 in a single operation in a soldering oven.

The gas outlet collector 18 may also be welded to the heat exchange assembly 10. In this instance, the gas outlet collector 18 may also be produced from an aluminum alloy.

Furthermore, according to the example illustrated, the gas outlet collector 18 may comprise in a similar manner to the collection plate 24 a generally rectangular peripheral edge 156 which delimits a gas passage opening 158 opposite the open face 54 of the heat exchange assembly 10 at the gas outlet side. This opening 158 forms an opening for the introduction of supercharging air into the cylinders of the engine (not illustrated).

Furthermore, the gas outlet collector 18 may also comprise a covered portion 60 to prevent the passage of the gas into an end region of the heat exchange assembly 10, which portion does not have any first channels 46. As above, this end region corresponds to the portion of the heat exchange assembly 10 which does not have any undulating inserts 42 and which comprises projections 34, 36, 34A, 36A, 34B, 36B, so that the gas to be cooled is channeled into the useful portion of the heat exchange assembly 10, which portion corresponds to the first channels 46 and comprises, for example, undulating inserts 42.

All of the elements of the heat exchange assembly 10, that is to say, the plates 28, 28A, 28B, the undulating inserts 42 and the intake and outlet tubes of the cooling liquid 12 and 14, and the collection plate 24 and the gas outlet collector, may therefore be assembled together and soldered in a single operation in a soldering oven. The assembly obtained in this manner is then assembled by means of crimping with the casing 161 of the gas intake collector 16.

It is also possible to make provision for the peripheral edge 156 of the gas outlet collector 18 to have, at the side facing the heat exchange assembly 10, a means for temporary retention on the heat exchange assembly 10 before the soldering operation. It may be, for example, a shoulder which is shaped to enable the gas outlet collector 18 to be fitted with respect to the heat exchange assembly 10.

According to a second embodiment illustrated in FIG. 7, the gas outlet collector 218 defines a space for collection of gas, in this instance the supercharging air.

The gas intake and outlet are indicated by arrows in FIG. 7.

It is further possible to provide a valve 270 which enables a portion of the exhaust gases from the engine, called recirculated exhaust gases, to be introduced into the gas intake collector 218.

The valve 270 may be fixed to the gas outlet collector 218.

The valve 270 is known as an EGR valve (Exhaust Gas Recirculation). In this instance, the cooled fluid is mixed with the recirculated exhaust gases in the gas intake collector 218, and the mixture obtained in this manner is introduced into the cylinders of the engine.

To this end, the gas outlet collector 218 comprises a device for injecting recirculated gases comprising, for example, an injection channel 272 which comprises a plurality of injection holes, or injectors 274, which are arranged, for example, in a linear manner, and an intake hole 276 (cf. FIG. 8).

The EGR valve 270 therefore enables the recirculated exhaust gases to pass via the intake hole 276 into the injection channel 272 and the recirculated exhaust gases from the EGR valve 270 are injected into the space defined by the outlet collector 218 via the injection holes 274.

The difference of assembly technology between the intake collector 16 and the outlet collector 218 in particular enables a reduction of cost. This is because the intake collector 16 may be produced from plastics material and crimped to the heat exchange assembly whilst the intake collector 218 in which the supercharging air is mixed with the recirculated exhaust gases is produced by means of casting in order to be welded or soldered to the heat exchange assembly 10 and can thus withstand high temperatures.

There have been described above an intake collector 16 which is assembled by means of crimping to the heat exchange assembly 10 and an outlet collector 18, 218 which is assembled by means of soldering or welding to the heat exchange assembly 10.

Of course, it is possible to make provision, in a variant, for the intake collector 16 to be the component which is soldered or welded to the heat exchange assembly 10 and for the outlet collector 18, 218 to be the component which is crimped to the heat exchange assembly 10.

Claims

1. A heat exchanger comprising: a heat exchange assembly which defines first circulation channels for the circulation of a gas to be cooled and second circulation channels for the circulation of a cooling liquid; andtwo gas intake and gas outlet collectors, respectively, which are assembled on two open faces of the heat exchange assembly, respectively, in which the first circulation channels open,wherein a first collector is crimped to the heat exchange assembly and the second collector is soldered or welded to the heat exchange assembly.

2. The heat exchanger as claimed in claim 1, wherein the gas intake collector is crimped to the heat exchange assembly and the gas outlet collector is welded or soldered to the heat exchange assembly.

3. The heat exchanger as claimed in claim 1, wherein the first collector which is crimped to the heat exchange assembly is produced by means of molding a plastics material or a metal material, such as an aluminum alloy.

4. The heat exchanger as claimed in claim 1, wherein the second collector which is soldered or welded to the heat exchange assembly is produced from a metal material, such as an aluminum alloy.

5. The heat exchanger as claimed in claim 1, wherein the two gas intake and gas outlet collectors are assembled on two opposing faces of the heat exchange assembly , respectively.

6. The heat exchanger as claimed in claim 1, wherein the first collector which is crimped to the heat exchange assembly comprises a collector casing and a collection plate in which the first channels of the heat exchange assembly open, and the collector casing has an open face which is delimited by a peripheral rim which is held by means of crimping against the collection plate.

7. The heat exchanger as claimed in claim 6, wherein the collection plate is generally in the form of a frame and comprises a generally rectangular peripheral edge which delimits a gas passage opening and which has a crimping rim which surrounds a recess for receiving the peripheral rim of the first collector which is crimped to the heat exchange assembly.

8. The heat exchanger as claimed in claim 1, characterized in that it is produced in the form of a supercharging air cooler of a thermal engine of a motor vehicle, the first circulation channels serving to circulate the supercharging air to be cooled.

9. The heat exchanger as claimed in claim 8, wherein the gas intake collector comprises a tube which is integrally molded, and the gas outlet collector has a supercharging air intake opening for the thermal engine of the vehicle.

10. The heat exchanger as claimed in claim 9, wherein the gas outlet collector defines a gas collection space in which the first circulation channels open, and comprises an injection channel for recirculated exhaust gases and a plurality of injection holes for recirculated exhaust gases for the injection of recirculated exhaust gases into the gas collection space of the gas outlet collector.

11. The heat exchanger as claimed in claim 10, wherein the gas outlet collector comprises an intake valve for the recirculated exhaust gases into the gas outlet collector.