EP0984237A1 - Multi-circuit heat exchanger, particularly for motor vehicles - Google Patents

Abstract

The heat exchanger has two circuits (C1, C2) formed by inner (14) and outer (16) U-shaped channels, and feed and return pipes (50, 52) linked to the channels to deliver identical or different fluids (F1). The channels are bounded by facing pairs of plates (12) and are connected through apertures (28, 32); in a variant they are formed by U-shaped tubes.

Description

The invention relates to a multi-circuit type heat exchanger, intended in particular for motor vehicles.

Conventionally, a heat exchanger comprises a bundle composed of a multiplicity of tubes in contact thermal with fins. The tubes are clean to be crossed by a first fluid (usually water or a refrigerant) which exchanges heat with a second fluid (usually air) that scans the beam. In the automotive field, the heat exchanger can be an engine cooling radiator or a heating radiator, both of which flow through the engine cooling.

It can also be an evaporator or a condenser being part of an air conditioning circuit and traversed both by a coolant.

There are single-circuit type heat exchangers, in which all the tubes of the bundle are traversed by the same fluid.

There are also multi-circuit type heat exchangers, in which the bundle tubes are grouped in at least two subsets that can be browsed by identical or different fluids. In this case, the tubes of the different sub-assemblies can be crossed by common fins, or by fins attached to them clean.

In known heat exchangers of the multi-circuit type, the beam subsets are made up of groups of parallel and juxtaposed tubes, which have in particular for disadvantage of not allowing good uniformity of temperatures, and to be relatively bulky.

The object of the invention is in particular to overcome the drawback cited above.

To this end, it offers a heat exchanger, in particular motor vehicle, which includes first channels in U defining a first fluid circuit, second U-shaped channels surrounding the first U-shaped channels and defining a second fluid circuit, connected supply means to the first channels and to the second channels to supply selectively the first circuit and / or the second circuit by respective fluids, which may be the same or different.

Thus, the heat exchanger of the invention comprises basically two sets of U-shaped channels which are nested tightly together, allowing obtain a reduced footprint compatible with use in modern motor vehicles for which the space allocated to equipment is increasingly reduced.

The first circuit, which can be called "interior circuit" or "central circuit", is wrapped on both sides by the second circuit, which can be called "external circuit".

As indicated above, these two circuits can be supplied by respective fluids, identical or different, which offers great flexibility of use.

In particular, when only the first circuit (circuit interior) is traversed by a fluid, the second circuit (external circuit), which is not powered, plays a role shock absorber and reduces, by mass effect, possible noises of flow of the fluid flowing first circuit.

In addition, this heat exchanger offers the advantage of being compatible with conventional manufacturing processes heat exchangers.

In a preferred embodiment of the invention, the first channels and the second channels are delimited by a stack of plates arranged in pairs, the two plates of the same pair being turned towards each other to jointly delimit a first channel and a second channel, and the pairs of plates communicating with each other by appropriate openings.

Thus, such a heat exchanger can be produced according to the known technology of plate heat exchangers, which find generally an application in the manufacture of evaporators air conditioning.

In another embodiment of the invention, the first and second channels are delimited respectively by a first series of U-shaped tubes and a second series of U-shaped tubes, these U-shaped tubes advantageously passing through parallel fins.

According to a characteristic of the invention, the supply means include only one inlet tubing connected together with the first channels and the second channels, and a single outlet tube connected jointly to the first channels and the second channels.

Alternatively, and according to a preferred characteristic of the invention, the supply means comprise a first inlet manifold and first outlet manifold connected to the first channels, as well as a second tubing inlet and a second outlet tubing connected to the second channels. To facilitate the feeding of the said tubing it is advantageous that the heat exchanger further includes an inlet pipe connected to the first inlet manifold and to the second inlet manifold, and an outlet pipe connected to the first pipe outlet and to the second outlet pipe to supply the first circuit and the second circuit by the same fluid, as well as an input bypass connected to the first inlet manifold and an outlet bypass connected to the first outlet pipe to allow supply to the first circuit by a fluid, selection means being provided to allow either the supply of the pipeline inlet and outlet piping, i.e. power input bypass and output bypass.

It is thus possible to selectively supply the first circuit and / or the second circuit.

In one embodiment, the selection means mentioned above include a set of two valves mounted respectively on the inlet pipe and the pipe of outlet and another set of two valves mounted respectively on the input bypass and the output bypass.

In another embodiment, the selection means aforementioned include two check valves, one of which is mounted on the first inlet pipe between the pipe input and input bypass, and the other is mounted on the first outlet pipe between the pipe of output and output bypass.

According to yet another characteristic of the invention, the first circuit and the second circuit are suitable to be traversed by the same fluid, and one or the other of the first circuit and the second circuit is suitable to be traveled to it alone by another fluid.

In a preferred embodiment of the invention, the first circuit and the second circuit are suitable to be traversed by a cold fluid, while the first circuit is capable of being traversed by itself by a hot fluid.

Thus, in a preferred application of the invention, the first circuit and the second circuit are suitable to be traversed by a refrigerant allowing cooling the surrounding air (operating as an evaporator), while the first circuit is suitable for being covered at it alone by a coolant evacuating heat (in functioning as a condenser).

In such a case, with the same heat exchanger, either operate as an evaporator to cool a flow of air, either function as a heating radiator for reheat an air flow.

According to another characteristic of the invention, the exchanger heat includes supply channels making communicate between them the first channels on the one hand and the second channels on the other hand, and at least one of these channels supply is fitted with a partition capable of modifying the distribution of the fluid in the first channels and / or the second channels.

• la figure 1 est une vue en perspective éclatée d'un échangeur de chaleur selon une première forme de réalisation de l'invention ;
• la figure 2 est une vue partielle de côté de l'échangeur de chaleur de la figure 1 ;
• la figure 3 est une vue en perspective d'une plaque propre à faire partie d'un échangeur de chaleur du type représenté à la figure 1 ;
• la figure 4 est une vue en perspective éclatée d'un échangeur de chaleur selon une deuxième forme de réalisation de l'invention ;
• les figures 5 et 6 illustrent schématiquement les circuits de l'échangeur de chaleur de la figure 4 dans deux modes de fonctionnement différents ;
• la figure 7 est une vue partielle en perspective, analogue à la figure 4, d'un échangeur de chaleur selon une troisième forme de réalisation de l'invention ;
• la figure 8 représente schématiquement les circuits de l'échangeur de chaleur de la figure 7 dans un mode de fonctionnement ;
• la figure 9 est une vue d'extrémité d'un échangeur de chaleur selon une quatrième forme de réalisation de l'invention ;
• la figure 10 est une représentation schématique en perspective d'un exemple d'un circuit d'un échangeur de chaleur selon l'invention fonctionnant en mode climatisation ; et
• la figure 11 est une représentation schématique en perspective d'un exemple d'un circuit d'un échangeur de chaleur selon l'invention fonctionnant en mode chauffage additionnel.

In the description which follows, given solely by way of example, reference is made to the appended drawings, in which:

• Figure 1 is an exploded perspective view of a heat exchanger according to a first embodiment of the invention;
• Figure 2 is a partial side view of the heat exchanger of Figure 1;
• Figure 3 is a perspective view of a plate suitable for being part of a heat exchanger of the type shown in Figure 1;
• Figure 4 is an exploded perspective view of a heat exchanger according to a second embodiment of the invention;
• Figures 5 and 6 schematically illustrate the circuits of the heat exchanger of Figure 4 in two different operating modes;
• Figure 7 is a partial perspective view, similar to Figure 4, of a heat exchanger according to a third embodiment of the invention;
• FIG. 8 schematically represents the circuits of the heat exchanger of FIG. 7 in an operating mode;
• Figure 9 is an end view of a heat exchanger according to a fourth embodiment of the invention;
• Figure 10 is a schematic perspective representation of an example of a circuit of a heat exchanger according to the invention operating in air conditioning mode; and
• Figure 11 is a schematic perspective representation of an example of a circuit of a heat exchanger according to the invention operating in additional heating mode.

We first refer to Figures 1 and 2 which represent a heat exchanger 10 according to a first form of realization of the invention, which is carried out according to technology plate heat exchangers. Interchange 10 comprises a stack of plates 12 arranged in pairs and each made by stamping a metal sheet, or again by molding, to form a first shaped channel 14 of U and a second channel 16 in the shape of U (figure 1). The first channel 14 comprises two parallel branches 18 joined together between them by a bend 20 of semi-circular shape. Of even, the channel 16 comprises two branches 22, parallel between them and a bend 24 of semi-circular shape. Channel 16 completely surrounds the channel 14, the branches 22 being substantially parallel to the branches 18 and the semi-circular part 24 being concentric with the semi-circular part 20. The ends of the branches 18 open into respective bosses 26 provided with corresponding openings 28. Likewise, the branches 22 lead to bosses respective 30, each provided with an opening 32. Each of the plates 12 is delimited by a plane peripheral edge 34 having a substantially rectangular outline.

Thus, when two plates 12 are joined by their edges respective 34, they jointly delimit two channels in U. Furthermore, as can be seen in Figures 1 and 2, the pairs of plates 12, once stacked, are in contact by their respective bosses, which makes it possible to communicate the different channels with each other. We represented schematically in Figure 1, a supply channel 36 which causes the bosses 26 to communicate with each other openings 28 and a supply channel 38 which makes communicate between them the bosses 30 by their openings respective 32.

Below the bosses, the plates 12 define two support planes 40 facing each other (Figure 2), which allows limit a flat space in which is housed, each time, a tab 42, of wavy shape, constituting a fin. To close the ends of the heat exchanger heat, an end plate 44 is provided each time generally planar, of which only one is visible on the Figure 1, the other being placed at the opposite end.

So the heat exchanger consists of a multiplicity shaped plates 12 arranged in pairs, spacers 42 each arranged between two facing plates belonging to different pairs, and two plates end. The different elements of the heat exchanger heat are advantageously made from a sheet metallic, preferably aluminum or base alloy aluminum, and these different elements are brazed together to form an assembled heat exchanger.

Channels 14, also called "interior channels" or "channels exchanges "communicate with each other and constitute a first fluid circuit, which can be called internal circuit. The second channels 16, which can be called "external channels", communicate with each other and constitute what we can call an external circuit, which envelops or surrounds the interior circuit.

In the embodiment of Figure 1, the plate end 44 is provided with a boss 46, called "boss input ", and a boss 48 called" output boss ". bosses are advantageously made by stamping the plate 44. The bosses 46 and 48 communicate respectively with an inlet manifold 50 and an outlet manifold 52. In this example, the bosses 46 and 48 are adapted to come each facing a couple of bosses 26 and 30 of the plate 12 which is immediately adjacent to the plate end 44.

It follows that an F1 fluid, for example a refrigerant, can supply heat exchanger 10. Fluid F1 enters through the inlet pipe 50 and feeds jointly a first circuit C1 formed by the first channels 14 and a second circuit C2 formed by the second channels 16, and leaves then the heat exchanger through the outlet pipe 52. The heat exchanger 10 of FIG. 1 advantageously constitutes an evaporator suitable for being part of a circuit air conditioning, so that an air flow which sweeps the exchanger heat 10 passes between the plates 12 coming in contact of corrugated inserts 42, to produce a flux refrigerated air.

Figure 3 shows a practical embodiment of a plate 12 can be used in the heat exchanger of the figure 1. A clear distinction is made between channels 14 and 16, the bosses 16 and 30, openings 28 and 32 and the edge device 34.

We now refer to Figure 4 which represents a heat exchanger according to a second embodiment of the invention. The main difference from the heat exchanger of figure 1 resides in the mode supply channels. In fact, the means of supply of the previous embodiment, and in particular the bosses 46 and 48 are replaced by supply means different. The exchanger of FIG. 4 comprises a first inlet manifold 54 and a first inlet manifold output 56 connected respectively to the first channels 14, as well as a second inlet pipe 58 and a second outlet pipe 60 connected to the second channels 16.

The heat exchanger according to this second embodiment is particularly advantageous in a thermodynamic loop can operate both in air conditioning mode or in additional heating mode. In cooling mode, the evaporator is used as a cooling medium. In mode additional heating, this same evaporator is used as heating means. It then allows to heat quickly the vehicle interior when the engine is cold.

There is also provided an inlet pipe 62 which is connected to the inlet pipes 54 and 58 and a pipe of outlet 64 connected to outlet pipes 56 and 60.

As a result, a fluid F1 can supply in parallel the two circuits C1 and C2 as in the case of FIG. 1.

As illustrated, the heat exchanger can include plus an input bypass 66 connected to the first tubing 54 and an output bypass 68 connected to the first outlet pipe 56, which makes it possible to supply only the first C1 circuit (central circuit) by a fluid F2 as shown by the arrows. This fluid F2 is advantageously different from the fluid F1.

As can be seen in Figures 5 and 6, the heat exchanger heat further comprises selection means for allow either the supply of pipes 62 and 64, or the supply of leads 66 and 68. In the example, these selection means include a set of two valves 70 and 72 (Figures 5 and 6) mounted respectively on the pipeline inlet 62 and outlet pipe 64 and a another set of two valves 74 and 76 mounted respectively on the input bypass 66 and the output bypass 68.

The air conditioning mode corresponds to the operating mode shown in Figure 5.

In this operating mode, the valves 70 and 72 are open, while valves 74 and 76 are closed. It results that circuits C1 and C2 are supplied jointly and traversed by the same fluid F1.

In this operating mode, the fluid F1 is advantageously refrigerant and the heat exchanger is working then as an evaporator to produce cold.

In addition, the additional heating mode corresponds to operating mode shown in Figure 6.

In this operating mode, the valves 70 and 72 are closed, while valves 74 and 76 are open. It As a result, only the circuit C1 is supplied by the fluid F2.

Fluid F2 is also a refrigerant, but when the circuit C1 is only supplied by the fluid F2, the evaporator then functions as a condenser, to produce heat.

In this latter operating mode, only the channels 14, arranged in the center, are fed, so that the rest of the volume of the heat exchanger, which is not used, serves damper for noise induced by fluid flow F2.

In the third embodiment shown in Figure 7, we find the same general structure of means supply than in the case of FIG. 4: pipes 54, 56, 58 and 60, lines 62 and 64 and branches 66 and 68.

However, and as can be seen in Figure 8, the valves 70, 72, 74 and 76 are deleted and replaced here by two non-return valves 78 and 80, one of which is mounted on the first inlet pipe 54 between the inlet pipe 62 and input bypass 66 and the other is mounted on the first outlet pipe 56 between the pipe of output 64 and output bypass 68. Circuits C1 and C2 can be supplied jointly by the fluid F1, the valves 78 and 80 not opposing the circulation of the fluid.

On the other hand, when only the circuit C1 is supplied by the fluid F2, check valves 78 and 80 allow only the circulation of the fluid F2 in the exchanger.

We now refer to Figure 9 which shows a fourth embodiment. In it, each of the first channels 14 is bounded by a U-shaped tube 82 and each channels 16 is delimited by a U-shaped tube 84, each tube 82 being "wrapped" by a tube 84. We thus has a series of tubes 82 each of which is surrounded by a tube 84. The tubes 82 and 84 pass through a multiplicity 86 flat fins to increase heat exchange between the fluids traveling respectively through the circuits C1 and C2 and an air flow A which scans the beam.

Tubes 82 communicate with an inlet manifold 88 and an outlet manifold 90 and, likewise, the tubes 84 communicate with a manifold inlet 92 and an outlet manifold 94.

As in the previous embodiments, the F1 and F2 circuits can each be powered by identical or different fluids. Feeding means selective or not, of the type described with reference to Figures 1 to 8, can therefore be provided.

Figure 10 shows an example of a circuit of a heat exchanger heat functioning as an evaporator (air conditioning mode), circuits C1 and C2 being both supplied by a cold fluid F1. Supply channels 36 and 38 include respective internal partitions 96 and 98 (Figure 1) placed in selected places, so that these channels have sections of different lengths, for example a section 100 of length L1 and a section 102 of length L2 such that L1 is less than L2 (Figure 10). this allows to ensure a selected distribution of the fluid F1 between the first channels 14 and the second channels 16.

Figure 11 shows an example of a circuit of a heat exchanger heat functioning as a condenser (heating mode additional), only one of the circuits C1 and C2 being supplied by a hot fluid F2. The circuits are the same as in the case of FIG. 10, but the second channels 16 are not not supplied and constitute "dead channels" represented schematically by broken lines.

In an exemplary embodiment, the first circuit C1 and the second circuit C2 are suitable for being traversed by a fluid cold F1, and the first circuit C1 is suitable for being traversed alone by a hot fluid F2. So we can predict that the first circuit C1 and the second circuit C2 are clean to be traversed by a refrigerant allowing cool the surrounding air, and that the first circuit C1 is suitable to be traversed by itself by a coolant dissipating heat.

Of course, the invention is not limited to the forms of realization described previously by way of examples, and extends to other variants.

Claims (11)

Heat exchanger, in particular for a motor vehicle, characterized in that it comprises first channels (14) in U defining a first fluid circuit (C1), second U-shaped channels (16) surrounding the first U-shaped channels (14) and defining a second fluid circuit (C2), means supply connected to the first channels (14) and to the second channels (16) for selectively supplying the first circuit (C1) and / or the second circuit (C2) by respective fluids (F1; F2), which may be the same or different. Heat exchanger according to claim 1, characterized in that the first channels (14) and the second channels (16) are delimited by a stack of plates (12) arranged in pairs, the two plates (12) of a pair being facing each other to jointly delimit a first channel (14) and a second channel (16), and the pairs of plates (12) communicating with each other through openings (28, 32). Heat exchanger according to claim 1, characterized in that the first channels (14) and the second channels (16) are delimited respectively by a first series of U-tubes (82) and a second series of U-tubes (84), these U-shaped tubes advantageously passing through fins (86). Heat exchanger according to one of claims 1 to 3, characterized in that the supply means comprise a single inlet pipe (50) connected jointly the first channels (14) and the second channels (16), and a single outlet pipe (52) connected jointly to the first channels (14) and second channels (16). Heat exchanger according to claim 4, characterized in that it further comprises an inlet pipe (62) connected to the first inlet pipe (54) and to the second inlet pipe (58), and an outlet pipe (64) connected to the first outlet pipe (56) and to the second outlet pipe (60) for supplying the first circuit (C1) and the second circuit (C2) by the same fluid (F1), as well as an input bypass (66) connected to the first inlet pipe (54) and a bypass of outlet (68) connected to the first outlet pipe (56) for allow the first circuit (C1) to be supplied with a fluid (F2), and in that selection means (70, 72, 74, 76; 78, 80) are provided to allow either the supply of the inlet pipe (62) and outlet pipe (64), i.e. the supply of the input bypass (66) and of the output bypass (68). Heat exchanger according to claim 5, characterized in that the selection means include a set of two valves (70, 72) mounted respectively on the pipeline inlet (62) and the outlet pipe (64), and a another set of two valves (74, 76) mounted respectively on the input bypass (66) and the output bypass (68). Heat exchanger according to claim 5, characterized in that the selection means comprise two non-return valves (78, 80), one of which is mounted on the first inlet pipe (54) between the pipe input (62) and input bypass (66), and the other is mounted on the first outlet pipe (56) between the outlet pipe (64) and outlet bypass (68). Heat exchanger according to one of claims 1 to 7, characterized in that the first circuit (C1) and the second circuit (C2) are suitable for being traversed by the same fluid (F1), and in that one or the other of the first circuit (C1) and of the second circuit (C2) is suitable for being traveled alone by a fluid (F2). Heat exchanger according to claim 8, characterized in that the first circuit (C1) and the second circuit (C2) are suitable for being traversed by a cold fluid (F1), and in that the first circuit (C1) is suitable for being traveled alone by a hot fluid (F2). Heat exchanger according to claim 9, characterized in that the first circuit (C1) and the second circuit (C2) are suitable for being traversed by a coolant allowing the surrounding air to be cooled, and in that the first circuit (C1) is suitable for being traveled alone by a coolant evacuating heat. Heat exchanger according to one of claims 1 to 10, characterized in that it comprises supply channels (36, 38) communicating with each other first channels (14) on the one hand and the second channels (16) on the other share and in that at least one of these feed channels is provided with a partition (96; 98) suitable for modifying the distribution of the fluid (F1; F2) in the first channels and / or the second channels.

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