WO2017109356A1

WO2017109356A1 - Heat exchanger, notably for a motor vehicle

Info

Publication number: WO2017109356A1
Application number: PCT/FR2016/053505
Authority: WO
Inventors: Isabelle Citti; Sébastien JACOPE
Original assignee: Valeo Systemes Thermiques
Priority date: 2015-12-21
Filing date: 2016-12-16
Publication date: 2017-06-29
Also published as: FR3045804A1; FR3045804B1; EP3394545A1; EP3394545B1

Abstract

The invention relates to a heat exchanger, notably for a motor vehicle, said exchanger comprising a heat exchange core bundle defining circulation canals (9) for at least one fluid. According to the invention, - the heat exchanger comprises a predefined number of frames (15) respectively defining a circulation canal (9) for said fluid, each frame (15) defining an internal width and an internal length (L), and – each frame (15) comprises at least one internal strip (150) of smaller width (W) than the said frame (15), and extending longitudinally inside said frame (15) over a length (l) less than the internal length (I) of the said frame (15) so as to define an at least two-pass path for the said fluid in the said frame (15).

Description

Heat exchanger, in particular for a motor vehicle

The invention relates to the field of heat exchangers.

In this respect, the invention relates more particularly to heat exchangers able to be traversed by a refrigerant fluid having a relatively high operating pressure, as is the case with natural gases such as carbon dioxide designated by CO ₂ , having an operating pressure higher than the refrigerant gases used in the solutions of the state of the art.

Such heat exchangers find particular application in motor vehicles. They may in particular constitute a gas cooler in which the cooling fluid such as CO ₂ is cooled by a second fluid, such as liquid. Conversely, the second fluid can be cooled by the first fluid for example in gaseous form, the heat exchanger is then commonly referred to as "Water chiller" in English.

Such heat exchangers can in particular be used in the thermal regulation of one or more batteries of an electric or hybrid vehicle. The thermal regulation of the batteries is an important point because if the batteries are subjected to temperatures too cold, their autonomy can decrease strongly and if they are subjected to too high temperatures, there is a risk of thermal runaway up to to the destruction of the battery, or even the motor vehicle. In order to regulate the temperature of the batteries, it is known to use a coolant, generally coolant comprising a mixture of brine, which circulates in a heat exchanger in contact with the battery or batteries. The cooling liquid can thus bring heat to the battery or batteries to heat them, this heat having been absorbed by the cooling liquid for example during the heat exchange with the C0 ₂ flowing in the gas cooler. The coolant can also, if necessary, absorb the heat emitted by the battery or batteries to cool them and remove this heat at one or more other heat exchangers.

Such heat exchangers can also be used like any other gas cooler in an air conditioning circuit.

However, the use of a cooling fluid such as C0 ₂ under a very high pressure, generally greater than 100 bar, with a burst pressure which can reach, for example, up to 340 bar, implies that heat exchangers such as gas coolers must withstand such high pressures.

Heat exchangers are known, for example, comprising a stack of plates allowing the circulation of the first fluid, such as the refrigerant or refrigerant gas, and the second fluid such as the cooling liquid. In order to improve the heat exchange, it is known to provide partition walls on these plates delimiting several passes of circulation of a fluid or two fluids. A problem related to the circulation of a fluid in several passes is to improve the heat exchange while reducing the pressure losses of the fluid. Furthermore, plate heat exchangers known from the prior art do not allow to withstand such high pressures.

Thermal heat exchangers are also known from the prior art, comprising a stack of tubes interconnected by at least one collector of the first fluid, in particular the refrigerant fluid on each side of the tubes, and the second fluid, for example in liquid form, can circulate. around the tubes in an envelope connected to a water box.

However, such an architecture is complex to achieve and in particular has drawbacks in terms of sealing, particularly in the case of a brazed heat exchanger for which it proves necessary to provide multiple soldering points for several pieces of the heat exchanger. In addition, with this architecture, the two fluids circulate generally at cross flow. It is not always possible to provide a flow against the current or in several passes of the two fluids, which limits the efficiency of the heat exchanger. It has also been found that such a heat exchanger does not always have good mechanical strength.

Moreover, a constant problem of heat exchangers implemented in a motor vehicle lies in the allocation of a reduced space, in order to meet the requirements of the manufacturers.

The present invention aims to improve the solutions of the state of the art and to at least partially solve the disadvantages described above by providing a simple heat exchanger to achieve having a better heat exchange performance, this by limiting the losses of charge.

For this purpose, the subject of the invention is a heat exchanger, in particular for a motor vehicle, said exchanger comprising a heat exchange bundle defining circulation channels for at least one fluid.

According to the invention,

the heat exchanger comprises a predefined number of frames respectively defining a circulation channel for said fluid, each frame defining an internal width and an internal length, and

each frame has at least one inner bar:

"Of smaller width than the said frame, and

Extending longitudinally inside said frame for a length less than the internal length of said frame,

so as to define a path in at least two passes for said fluid in said frame.

Such frames allow, in a simple manner, a circulation in at least two passes of at least one fluid, for example coolant, in the heat exchanger, thus improving the performance of the heat exchanger.

In the invention, the frames designate a part, or an assembly of parts, which can be rigid, delimiting a closed space or not. In this space can be positioned, in our example, heat exchange tubes.

It will be noted that the heat exchange bundle, which comprises a plurality of heat exchange tubes, is distinct from the frames.

The heat exchanger may further comprise one or more of the following features taken alone or in combination:

the inner bar extends over a length at least equal to half the length internal of said frame. The dimensions of the strip thus chosen make it possible to optimize the thermal performances while limiting the pressure drops;

said frame and the inner bar are shaped to verify the following relationship: 0.49 <- <0.95;

The

the internal length of said frame is in a range of about 30mm to 500mm;

each frame is of substantially rectangular shape, and the inner bar extends from an edge of said frame forming a small side extending in the width direction;

said frame comprises an edge substantially parallel to the inner bar and having at least one fluid inlet extending over a length of fluid inlet, and the inner bar is arranged inside said frame away from said edge presenting fluid inlet by a lateral distance, such that the fluid inlet length is greater than or equal to the lateral distance, according to the relation: L1> L2;

the inner strip is arranged substantially in the center of said frame in the width direction of said frame;

the lateral distance between the inner bar and the two opposite edges of said frame parallel to the inner bar is the same on each side of the inner bar; said frame has no bar on a remaining length between the free longitudinal end of the inner bar and the edge of said frame facing the free longitudinal end of the inner bar extending substantially perpendicular to the inner bar, and the length extension of the inner bar is chosen so that the lateral distance is greater than or equal to the remaining length, according to the relation: L2≥ L3 = L-1;

the lateral distance is in a range of about 15mm to 60mm;

the heat exchanger comprises at least one inlet pipe and an outlet pipe for said fluid, and said frames respectively have through-openings for placing in fluid communication with the inlet and outlet pipes, and opening respectively onto the pipe. inside said frame, at least one through opening defining a fluid inlet;

said frames respectively have at least two handles defining the fluidic communication opening openings, and formed on two opposite edges of said frame extending substantially parallel to the inner bar;

said frame and each fluidic communication opening are shaped to define a fluidic communication area within a range of which:

The upper limit corresponds to three times the product of the length of fluid inlet with the remaining length, and

The lower limit is the tenth of the product of the fluid inlet length with the remaining length,

in order to verify the following relation:

0.1 x 11 x L3 <51 <3 x L x L 3

the thickness of said frame is of the order of 0.5mm to 4mm, preferably of the order of 2mm, in the stacking direction of said frames;

the width of the inner bar is greater than or equal to, preferably greater than, the thickness of said frame, in the stacking direction of said frames; each frame includes flow turbulators of said fluid disposed on either side of the inner bar;

the thickness of the turbulators is substantially equal to the thickness of said frame, in the stacking direction of said frames.

According to another aspect of the invention, the heat exchanger allows a heat exchange between at least a first fluid and a second fluid, and comprises an alternating stack of first heat exchange tube receiving frames defining first circulation channels. for the first fluid, and second frames respectively defining second circulation channels for the second fluid and respectively comprising said at least one inner bar.

The heat exchanger thus comprises a stack of simple elements, namely first frames in which the first fluid circulates, such as a fluid refrigerant, and between which second frames are arranged, the second fluid such as coolant flowing in these second frames.

The superimposed frames make it possible to create the flow path of the first fluid such as a refrigerant, when the frames are assembled, preferably by brazing, and likewise the superposed frames make it possible to create the flow path of the second fluid. such as coolant in particular on two opposite sides of the heat exchange bundle.

Such an architecture allows a simpler embodiment of the heat exchanger as a whole which has a small footprint while having interesting properties to best withstand high local pressures, particularly due to the circulation of CO ₂ as a refrigerant in the first frames.

According to yet another aspect, the heat exchanger is assembled by soldering. Other features and advantages of the invention will emerge more clearly on reading the following description, given by way of illustrative and nonlimiting example, and the appended drawings among which:

FIG. 1 is a perspective view of a heat exchanger, and

FIG. 2 is a perspective view of a frame of the heat exchanger of FIG.

In these figures, substantially identical elements have the same references.

The following achievements are examples. Although the description refers to one or more embodiments, this does not necessarily mean that each reference relates to the same embodiment, or that the features apply only to a single embodiment. Simple features of different embodiments may also be combined to provide other embodiments.

In the present, the terms upper and lower, or high and low, or vertical and horizontal, are designated by reference to the arrangement of the elements on the FIGS. This arrangement corresponds to the inverted arrangement of the elements in the mounted state in a motor vehicle in particular.

Heat exchanger

With reference to FIG. 1, the invention relates to a heat exchanger 1, in particular for a motor vehicle, for a heat exchange between at least a first fluid and a second fluid.

The first fluid can enter the heat exchanger 1 in gaseous form and the second fluid in liquid form.

It is in particular a heat exchanger assembled by brazing. To do this, the heat exchanger 1 has at least partially, that is to say on at least some elements or parts, a coating intended to melt to ensure the joining of elements of the heat exchanger during the heat exchange. soldering assembly.

Such a coating is commonly referred to as "clad" in English in the field of brazing metal parts, in particular aluminum.

The heat exchanger 1 according to the invention is particularly suitable for the circulation of at least one fluid having a high operating pressure, in particular greater than 100 bar.

For example, the first fluid is a refrigerant intended to circulate at high pressure such as C0 ₂ , also designated R744 according to the industrial nomenclature.

The heat exchanger 1 can in particular be a gas cooler in which the cooling fluid such as CO ₂ is cooled by a second fluid for example in liquid form, such as cooling liquid comprising a mixture of brine.

The second fluid such as the coolant can also be cooled by the first fluid such as CO ₂ , such a heat exchanger is then commonly referred to as "Water chiller" in English.

The heat exchanger 1 comprises a heat exchange bundle 3 for the heat exchange between the first fluid and the second fluid.

In the illustrated example, the heat exchange bundle 3 has a shape generally parallelepipedal.

The circulation of the first and second fluids is advantageously countercurrent in the heat exchange bundle 3.

The introduction and the evacuation of the first fluid in the heat exchange bundle 3 or outside the heat exchange bundle 3 is shown schematically by way of example by the arrows Fli for the introduction and Flo for the evacuation.

Similarly, the introduction of the second fluid into the heat exchange bundle 3 and the evacuation of the second fluid out of the heat exchange bundle 3 is shown schematically by way of example by the arrows F2i for the introduction and F2o for evacuation.

Finally, the heat exchanger 1, and more precisely the heat exchange bundle 3, can be configured for circulation in at least two passes of one of the two fluids, in this case at least the second fluid, or even a circulation at minus two passes of both fluids.

An example of circulation of the two fluids against the current and in two passes is illustrated schematically by the arrows F1 and F1 in FIG.

More precisely, the heat exchange bundle 3 alternately comprises first circulation channels for the first fluid (not visible in the figures) and second circulation channels 9 for the second fluid (see FIG. 2).

According to a preferred embodiment, the heat exchange bundle 3 comprises a plurality of heat exchange tubes (not visible in the figures) stacked so as to alternately define the first circulation channels for the first fluid in the tubes. heat exchange (not visible in the figures) and the second circulation channels 9 for the second fluid between the heat exchange tubes (not visible in the figures).

The heat exchange tubes may be made by extrusion, for example in the form of flat tubes, advantageous in terms of space.

The first channels or micro-channels (not visible in the figures) then extend substantially longitudinally, in a direction parallel to the direction longitudinal heat exchange tubes (not visible in the figures).

The first fluid can follow a circulation in a so-called "I" or rectilinear flow, but also alternatively a circulation in at least two passes, for example a circulation called "U".

Advantageously, the heat exchange tubes (not visible in the figures) can be received in first frames 13.

Interlayers are advantageously arranged between the first frames 13, and define the pitch between the heat exchange tubes (not visible in the figures) for example received in the first frames 13.

According to the invention, the second circulation channels 9 are defined by frames 15, hereinafter referred to as second frames 15.

Moreover, turbulators (not shown) of the flow of the second fluid may advantageously be arranged in the second circulation channels 9 defined by the second frames 15, thus improving the heat exchange between the two fluids.

The turbulators (not shown) may for example be substantially crenellated in shape, forming projections in the second circulation channels 9.

According to one embodiment, the heat exchange bundle 3 comprises an alternating stack of first frames 13 and second frames 15.

A plurality of second frames 15 arranged between two successive first frames 13 form the spacers.

The stack is here substantially vertically.

Each first frame 13 is able to define at least one first circulation channel for the first fluid, for example each first frame 13 is adapted to receive at least one heat exchange tube, and this assembly forms a stage of the exchange beam thermal 3.

The first frames 13 can be designated by tube frames.

Each second frame 15 can receive turbulators and this assembly forms another stage of the heat exchange bundle 3.

These two sets or floors are repeated as many times as necessary following Γ available space and performance to achieve.

The first frames 13 and the second frames 15 are described in more detail below.

By way of example, closure plates 17, 18, in particular at least one bottom closure plate 17 and at least one top closure plate 18, can be arranged on either side of the stack of the first frames. 13 and second frames 15, so as to close the heat exchange bundle 3.

The closure plates 17, 18 advantageously have a shape complementary to the shape of the first frames 13 and the second frames 15.

The heat exchanger 1 further comprises at least one manifold 19 of the first fluid arranged in fluid communication with the first circulation channels in the first frames 13.

The collecting box 19 is according to the illustrated example arranged on an upper closure plate 18 disposed at the top of the heat exchange bundle 3.

Of course, according to a variant not illustrated, the manifold 19 can be arranged on the lower closure plate 17 disposed at the bottom of the heat exchange bundle 3.

The same manifold 19 can be compartmentalized, so as to define firstly the introduction of the first fluid shown schematically by the arrow Fli in Figure 1 and secondly the evacuation of the first fluid schematized by the arrow Fl ₀ on Figure 1.

The heat exchanger 1 further comprises at least two inlet and fluid outlet pipes 21 for introducing and evacuating the second fluid.

In this example, the two tubes 21 are arranged on the same upper closure plate 18 as the manifold 19 for the first fluid.

Of course, according to a variant not illustrated, it is possible to arrange the two pipes 21 on the bottom plate 17.

According to a variant not illustrated, provision can be made to arrange separately the pipes 21, with a pipe 21 on the upper closure plate 18 and the other tubing 21 on the lower closure plate 17.

In particular, the manifold 19 can be arranged on one side of the heat exchange bundle 3 and the tubes 21 can be arranged on the other side of the heat exchange bundle 3, thus allowing a counter-current circulation of two fluids.

According to the arrangement illustrated in Figure 1, the manifold 19 is arranged on the left while the pipes 21 are arranged on the right.

Furthermore, it is preferable to provide a two-pass, so-called "U" circulation, of the first fluid in a first reception frame 13, and a two-pass circulation, called a "U" circulation, of the second fluid in a second frame 15.

The heat exchanger 1 is then double "U" circulation.

First frames called tubes-frames

Regarding the first frames 13, they can be at least partially made of aluminum.

These first frames 13 may have a thickness of the order of a few millimeters, for example of the order of 1 mm.

When they receive heat exchange tubes (not shown in the figures), these first frames 13 may have the same thickness as the heat exchange tubes they receive.

The thickness is considered in the direction of the height of the heat exchange bundle 3, we can also speak of the height of the first frames 13. This is the thickness in the stacking direction of the frames 13, 15.

Thus, the heat exchange tubes can be maintained in the first respective frames 13 before superposition of the different frames.

Each first frame 13 may receive a heat exchange tube or alternatively at least two heat exchange tubes, so that the heat exchange bundle 3 then has at least two rows of heat exchange tubes.

Moreover, in order to allow a circulation in at least two passes of the first fluid, two adjacent heat exchange tubes arranged in a first frame 13 can communicate with one another at one end.

The first frames 13 are for example of substantially rectangular general shape.

However, according to other embodiments, one could provide frames having a general shape that is not rectangular, for example elliptical, or diamond-shaped.

Moreover, in order to allow the flow of the first fluid in the heat exchange bundle 3, the first frames 13 comprise means for placing in fluid communication (not visible in the figures) the first circulation channels of the first fluid with the collector box 19.

The means of fluid communication (not visible in the figures) of each first frame 13 are advantageously arranged in fluid communication with the means for placing in fluid communication the other first frames 13 of the heat exchange bundle 3 and with the collecting box 19.

These means of setting fluid communication (not visible in the figures) are for example made in the form of recesses defining through openings for setting fluid communication, in which open the first flow channels of the first fluid, including the longitudinal ends, heat exchange tubes received in the first frames 13.

Through-openings are advantageously arranged on two opposite edges of the first frames 13. This is for example the lateral edges of the first frames 13 extending in the width direction of the heat exchanger 1.

The means of fluid communication provided on the first frames allow, in a simple manner, to collect the first fluid and distribute it for example in the heat exchange tubes held in these first frames.

It is no longer necessary to provide the collectors on each side of the tubes as in the known solutions.

Moreover, in order to allow the flow of the second fluid into the heat exchange bundle 3, the first frames 13 also have guides 134 for the passage of the second fluid.

According to the illustrated example, the first frames 13 are respectively shaped with at least one loop 134 which when at least one heat exchange tube is arranged in the first frame 13 defines a through hole for the flow of the second fluid .

The loops 134 of each first frame 13 are arranged in alignment with the handles 134 of the other first frames 13 of the heat exchange bundle 3 so as to allow the flow of the second fluid through the heat exchange bundle 3.

As an illustrative example, in the figures there is shown an embodiment of the loops 134 of substantially rounded shape.

Of course, any other form of the handles 134 may be considered.

The first reception frames 13 may be made by stamping cut.

Second frames

With reference to FIG. 2, the second frames 15 are now described in more detail.

The second frames 15 may be at least partially made of aluminum.

The second frames 15 may be made by stamping cut.

The second frames 15 have a thickness Th which is of the order of a few millimeters, for example of the order of 0.5mm to 4mm, preferably of the order of 2mm.

The thickness is here considered in the direction of the height of the heat exchange bundle 3, we can also speak of the height of the second frames 15. In this example, it is the thickness in the stacking direction of the frames 13, 15.

The thickness or height of the second frames 15 makes it possible to define the pitch between the first frames 13.

A plurality of second frames 15 called interleaves, arranged between two first frames 13 for receiving the heat exchange tubes 5, thus define the pitch between two stages of the heat exchange bundle 3 in which the first fluid flows.

When the second frames 15 receive turbulators (not shown), the second frames 15 are said frames-turbulators or turbulators frames. The thickness of the turbulators (not shown) may be substantially equal to the thickness Th of a second frame 15.

Advantageously, the second fluid can circulate in at least two passes in each second frame 15.

According to the illustrated embodiment, the second fluid can circulate in two passes, according to a circulation called "U" circulation, in each second frame 15.

The second frames 15 have two opposite edges 15A, 15B extending perpendicular to the general direction of flow of the second fluid and two other opposite edges 15C, 15D extending parallel to the general direction of the second fluid.

The general direction of flow of the second fluid here means the direction of the branches of the "U" in the case of a two-pass circulation of the second fluid.

In the illustrated examples, the second frames 15 are of generally rectangular shape. The second frames 15 present in this case:

two side edges 15A, 15B, forming short sides, extending in the width direction, and

two longitudinal edges 15C, 15D, forming long sides.

The second frames 15 advantageously have a shape similar to and complementary to the shape of the first frames 13.

In particular, the outer contours of the first frames 13 and second frames 15 are substantially identical so that the alternating stack of the first frames 13 and second frames 15 forms a block.

According to the illustrated embodiment, the second frames 15 extend on the same length and on the same width as the first frames 13. As said above, the heat exchanger 1 is preferably assembled by brazing. In this case, the second frames 15 are intended to be assembled by soldering to the first frames 13.

In particular, the longitudinal edges 15C, 15D of the second frames 15 are intended to be assembled by soldering to the longitudinal edges of the first frames 13 and the lateral edges of the second frames 15 are intended to be soldered to the lateral edges of the first frames 13.

More particularly, each second frame 15 defines an internal width and an internal length L (see FIG. 2).

The term "internal width", the width defined between the inner walls, giving on the inside of the second frame 15, opposite longitudinal edges 15C and 15D.

The term "internal length", the length L defined between the inner walls, giving on the inside of the second frame 15, opposite side edges 15A and 15B.

In addition, the lateral edges of the second frames 15 may be slightly larger than the lateral edges of the first frames 13, so that when heat exchange tubes are received in the first frames 13, the ends of these exchange tubes thermal (not shown), rest on the peripheral edge of the lateral edges of the second frames 15.

The second frames 15 define in this case an internal length L less than the internal length defined by the interior space of the first frames 13.

In other words, the internal length L of a second frame 15 is defined relative to the surface of the second frame 15 which is actually traversed by the second fluid.

In addition, the second frames 15 each comprise at least one bar 150, arranged inside the second frame 15 so as to separate two flow passes for the second fluid. It is therefore an internal bar 150.

In the illustrated example, the bar 150 makes it possible to shape the second circulation channel 9 defined by a second frame 15 that is substantially "U" shaped. According to the illustrated embodiment, a second frame 15 comprises a single bar 150.

Of course, it would be possible to provide a circulation of the second fluid in addition to two passes in a second frame 15 and for this purpose more than one bar 150 inside the second frame 15 which would be, by way of non-limiting example, arranged in an offset manner and opposite to each other.

When the second frames 15 receive turbulators (not shown) flow of the second fluid, the turbulators are then advantageously arranged on either side of the or each inner bar 150.

The or each bar 150 extends longitudinally inside a second frame 15.

The or each bar 150 therefore extends in this example substantially parallel to the longitudinal edges 15C and 15D of the second frame 15.

The bar 150 does not extend over the entire internal length L of the second frame 15. In other words, the bar 150 extends from a lateral edge 15A of a second frame 15 towards the opposite lateral edge 15B but without reaching this point. opposite side edge 15B.

The inner bar 150 thus extends longitudinally from a side edge 15A of a second frame 15 towards the opposite side edge 15B but without reaching the opposite side edge 15B.

The bar 150 is secured to a side edge 15A of a second frame 15 and projects with its free end towards the internal space of the second frame 15 towards the opposite side edge 15B, leaving a space.

The inner bar 150 thus extends longitudinally from a lateral edge 15A of a second frame 15 over a length l less than the internal length L of a second frame 15.

The inner bar 150 does not extend over the entire internal width of the second frame 15. More specifically, the inner bar 150 has a width W smaller than the internal width of the second frame 15.

The width W of the inner bar 150 may be greater than or equal to preferably strictly greater than the Th thickness of the second frame 15.

The inlet and the outlet of the flow path for the second fluid are thus defined on each side of the bar 150. The bar 150 may also be called tongue.

In addition, the bar 150 is substantially of the same thickness as the second frame 15.

The bar 150 is for example arranged substantially centrally. More specifically, the bar 150 is arranged substantially in the center of a second frame 15 in the width direction of the second frame 15. In this way, the bar 150 divides the second frame 15 into two parts of the same size.

Advantageously, the inner bar 150 extends over a length l at least equal to half the internal length L of a second frame 15.

In particular, each second frame 15 and the inner bar 150 of this second given frame 15 can be shaped so as to verify the following relation (a):

(a): 0.49 <- <0.95 with

the length of extension of the inner bar 150, and

L = internal length of the second frame 15.

Preferably, the upper bound is also defined by a strict relation, so that the second frame 15 and its inner bar 150 satisfy the following relation (a '):

(a '): 0.49 <- <0.95.

According to an exemplary embodiment, each second frame 15 may have an internal length L in a range of about 30mm to 500mm.

Furthermore, complementary to the first reception frames 13, the second frames 15, in particular the second spacer frames 15 arranged between two first frames 13, have guides for the passage of the first fluid allowing its flow in the stack of the first frames 13 and second frames 15.

The guides, for example made in the form of through holes, are, for example, arranged in the alignment of the fluidic communication connection means of the first reception frames 13.

In addition, the second frames 15 respectively have means for fluid communication 152 of the second circulation channels 9 between them on the one hand and with the pipes 21 for the second fluid on the other hand.

The means of fluid communication 152 provided on the second frames 15 allow, in a simple way, to collect the second fluid and distribute it in the second frames 15.

According to the example illustrated in FIG. 2, each second frame 15 has a predefined number of through-openings 152 for fluidic communication, for example here two through-openings 152 for putting into fluid communication. These through openings 152 are here arranged on the longitudinal edges 15C and 15D of the second frames 15 and are aligned with each other in the direction of the height of the heat exchange bundle 3.

The through openings 152 open respectively to the inside of a second frame 15.

In addition, in the example illustrated in Figures 1 and 2, the through openings 152 are arranged on the same side of a second frame 15 in the longitudinal direction, that is to say here to the right or left, in a complementary manner to the arrangement of the pipes 21 on the same side of the heat exchange bundle 3.

The through openings 152 make it possible to define a fluid inlet 152 towards the interior space of the second frame 15, which is in the illustrated example, provided on a longitudinal edge 15C, and a fluid outlet 152 outside the second frame 15, which is in the illustrated example, arranged on the opposite longitudinal edge 15D.

More specifically, according to the illustrated example, the second frames 15 have handles 153 which define the through openings 152.

The loops 153 of the second frames 15 are made similarly to the loops 134 of the first frames 13 and are aligned with these handles 134 which allow the passage of the second fluid through the heat exchange bundle 3.

By way of illustration, the figures show an embodiment of the handles 153 substantially rounded shape.

The shape of the handles 153 of the second frames 15 is complementary to the shape of the handles 134 of the first frames 13.

Of course, any other form of the handles 153 may be considered.

Among the two loops 153 of the second frames 15, the opening delimited by a first loop 153 is arranged in fluid communication with a first pipe 21 and the opening delimited by a second loop 153 is arranged in fluid communication with a second pipe 21.

In addition, according to the embodiment illustrated in FIG. 2, the fluid inlet 152 extends over a maximum fluid inlet length L1.

This maximum fluid inlet length L1 is, according to the particular embodiment illustrated, defined by the maximum length of the loop 153, at the beginning of its formation on the second frame 15.

Furthermore, the inner bar 150 is arranged inside a second frame 15 so that the bar 150 is spaced from a lateral distance L2, here in the width direction, of the longitudinal edge 15C of the second frame 15 presenting the fluid inlet 152.

In particular in this example, the central strip 150 is spaced from the same lateral distance L2 of each longitudinal edge 15C, 15D of the second frame 15.

This lateral distance L2 is considered with respect to the portion of the edge, here the longitudinal edge 15C or 15D, which extends parallel to the bar 150, and not with respect to the handle 153 formed on the side of the longitudinal edge 15C or 15D.

Advantageously, the fluid inlet length L1 is greater than or equal to the lateral distance L2 according to relation (b):

(b): L1> L2

with

Ll = maximum fluid inlet length and

L2 = lateral distance between the bar and the longitudinal edge of the frame.

Preferably, the fluid inlet length L1 is strictly greater than the lateral distance L2 according to the relation (b '): (b '): L1> L2

In addition, the lateral distance L2 between the inner bar 150 and the edge, here the longitudinal edge 15C or 15D, of a second frame 15, extending parallel to the inner bar 150, is greater than or equal to the remaining length L3 of the second frame 15:

between the free longitudinal end of the inner bar 150 and

the edge, here the lateral edge of the 15B, of the second frame 15 facing the end of the inner bar 150 extending substantially perpendicular to the inner bar 150, in other words the remaining length L3 without bar 150, according to the relation: (c): 12≥ L3 = L - l

with

L3 = remaining length without internal bar 150,

the length of extension of the inner bar 150, and

L = internal length of the second frame 15. Preferably, the lateral distance L2 and the remaining length L3 satisfy a strict relation (c '):

(c '): 12> L3 = L - 1.

As a nonlimiting example, the lateral distance L2 is in a range of the order of 15mm to 60mm.

Furthermore, each through opening 152 defines a fluid communication connection area S 1.

According to a particular embodiment, each through aperture 152 is shaped so that the fluid communication connection area SI is in a range having:

an upper limit corresponding to three times the product of the length of fluid inlet L1 with the remaining length L3, and

a lower bound corresponding to one-tenth of the product of the fluid inlet length L1 with the remaining length L3.

In other words, each through opening 152 is shaped so that the fluidic communication establishment area SI verifies the following relation (d):

(d): 0.1 x L1 x L3 <51 <3 x L1 x L3

with

51 = area of fluid communication.

Ll = maximum fluid inlet length and

L3 = remaining length without internal bar 150.

Preferably, each through aperture 152 is shaped such that the fluid communication setup area S1 satisfies a strict relation (d '):

(d '): 0.1 x L1 x L3 <51 <3 x L1 x L3.

The through openings 152 further define respectively a fluid inlet area S2 which is therefore equal to the product of the maximum length of fluid inlet L1 by the thickness Th or height of the second frame 15, according to the relation (e) next :

(e): 52 = L1 x Th.

with

52 = area of fluid inlet,

Ll = length d! maximum fluid inlet and

Th = thickness of the second frame 15 in the stacking direction.

Similarly, the second frame 15 defines a lateral deviation area S3 between the inner bar 150 and a longitudinal edge 15C of the second frame 15 which is therefore equal to the product of the lateral distance L2 by the thickness Th or height of the second frame 15, according to the following relation (f):

(f): 53 = L 2 x Th.

with

53 = area of lateral deviation.

L2 = lateral distance between the bar and the longitudinal edge of the frame, Th = thickness of the second frame 15 in the stacking direction. Finally, the second frame 15 defines a remaining area S4 equal to the product of the remaining length L3 by the thickness Th of the second frame 15, according to the following relation (g):

(g): 54 = L3 x Th = (L - 1) x Th.

with

54 = remaining area,

the length of extension of the inner bar 150, and

L = internal length of the second frame 15.

Thus, the internal strip 150 as described above, defining several flow passes for the second fluid, for example the cooling liquid, in a second frame 15 has dimensions advantageously chosen to optimize the thermal efficiency of the heat exchanger 1 while limiting the coolant pressure losses.

Claims

1. Heat exchanger (1), in particular for a motor vehicle, said exchanger (1) comprising a heat exchange bundle (3) defining circulation channels (9) for at least one fluid,

characterized in that

the heat exchanger (1) comprises a predefined number of frames (15) respectively defining a circulation channel for said fluid, each frame (15) defining an internal width and an internal length (L), and in that - each frame (15) comprises at least one inner bar (150) of smaller width (W) than said frame (15), and extending longitudinally inside said frame (15) to a length (l) less than the internal length (L) of said frame (15), so as to define a path in at least two passes for said fluid in said frame (15).

2. Heat exchanger (1) according to the preceding claim, wherein the inner bar (150) extends over a length (l) at least equal to half the internal length (L) of said frame (15).

3. Heat exchanger (1) according to the preceding claim, wherein said frame (15) and the inner bar (150) are shaped so as to verify the following relationship: 0.49 <- <0.95

The

4. Heat exchanger (1) according to one of the preceding claims, wherein the internal length (L) of said frame (15) is in a range of the order of

30mm to 500mm.

5. Heat exchanger (1) according to any one of the preceding claims, wherein: said frame (15) comprises an edge substantially parallel to the inner bar (150) and having at least one fluid inlet (152) extending over a fluid inlet length (L1), and wherein

the inner bar (150) is arranged inside said frame (15) away from said edge having the fluid inlet (152) by a lateral distance (L2), such as the fluid inlet length ( Ll) is greater than or equal to the lateral distance (L2), according to the relation: L1> L2

Heat exchanger (1) according to the preceding claim, wherein:

said frame (15) has no bar (150) on a remaining length (L3) between the free longitudinal end of the inner bar (150) and the edge of said frame (15) facing the free longitudinal end of the inner bar (150) extending substantially perpendicular to the inner bar (150), and wherein

the length (l) of extension of the inner bar (150) is chosen so that the lateral distance (L2) is greater than or equal to the remaining length (L3), according to the relation: L2≥ L3 = L-1

Heat exchanger (1) according to one of claims 5 or 6, wherein the lateral distance (L2) is in a range of the order of 15mm to 60mm.

Heat exchanger (1) according to any one of claims 5 to 7, comprising at least one inlet pipe and an outlet pipe (21) for said fluid, and wherein said frames (15) respectively have through openings ( 152) in fluid communication with the inlet and outlet pipes (21), and opening respectively on the inside of said frame (15), at least one through opening (152) defining a fluid inlet.

Heat exchanger (1) according to the preceding claim, wherein said frames (15) respectively have at least two handles (153) defining the fluidic communication opening openings (152), and formed on two edges opposed (15C, 15D) of said frame (15) extending substantially parallel to the inner bar (150).

The heat exchanger (1) according to claims 5 and 6 taken in combination with any one of the preceding claims, wherein said frame (15) and each fluidic communication opening (152) are shaped to define a area of fluid communication (SI) within a range of which:

the upper limit corresponds to three times the product of the fluid inlet length (L1) with the remaining length (L3), and

the lower limit is the tenth of the product of the fluid inlet length (L1) with the remaining length (L3),

in order to verify the following relation:

0.1 x L1 L3 <L <3 L x L x L3

11. heat exchanger (1) according to any one of the preceding claims, wherein the thickness (Th) of said frame (15) is of the order of 0.5mm to 4mm, preferably of the order of 2mm, in the stacking direction of said frames (15).

12. Heat exchanger (1) according to any one of the preceding claims, wherein the width (W) of the inner bar (150) is greater than or equal to, preferably greater than, the thickness (Th) of said frame ( 15) in the stacking direction of said frames (15).

13. Heat exchanger (1) for a heat exchange between at least one premeir fluid and a second fluid, according to any one of the preceding claims, comprising an alternating stack of:

first frames (13) for receiving heat exchange tubes defining first circulation channels for the first fluid, and

second frames (15) respectively defining second circulation channels for the second fluid and respectively comprising said least one inner bar (150).