Heat exchanger for a motor vehicle

Abstract

The invention relates to a heat exchanger (50) for a motor vehicle, comprising:-a first heat exchange section (1) configured to allow heat exchange between a refrigerant fluid and an air flow (F), comprising a first bundle tube (3) forming a set of flow-through channels for the refrigerant fluid,-a second heat exchange section (2) configured to allow heat exchange between the refrigerant fluid and the air flow (F), comprising a second bundle tube (3) forming a set of flow-through channels for the refrigerant fluid, the invention relates to a heat exchanger (1) configured to allow heat exchange between a heat transfer liquid and an air flow (F), comprising a second bundle tube (4) forming a set of heat transfer liquid flow channels, in which the tubes (3) in the first bundle tube have a U-shape with a first branch (5) and a second branch (7) connected by a base (6), in which the first branch (5) is arranged upstream of the second branch (7) in the flow direction of the air flow (F), and the second branch (7) is arranged downstream of the base (6) in the flow direction of the air flow (F). And wherein the second bundle tube (4) is arranged between the first branch (5) and the second branch (7) of the tube (3).

Description

Technical Field

[0001] The present invention relates to the field of heat exchangers, in particular to heat exchangers for motor vehicles. Such an exchanger can be installed in a thermal regulation system mounted on a motor vehicle. In the case of an electric vehicle, such a thermal regulation system makes it possible to ensure the thermal regulation of various parts of the vehicle, such as the interior of the car or an electrical energy storage battery. The heat exchange is mainly managed by the compression and expansion of a refrigerant circulating in a circuit in which a plurality of heat exchangers are arranged. A compressor makes it possible to bring the refrigerant to high pressure and circulate it in the circuit. Background Art

[0002] A refrigerant circuit generally includes a first heat exchanger that ensures the condensation of the high-pressure refrigerant discharged by the compressor, or its cooling in the case where the fluid is in a supercritical state. The refrigerant circulates in this first exchanger and releases heat to an air flow passing through the heat exchanger.

[0003] In addition, it is also common to cool the components of a vehicle powertrain by circulating a heat transfer liquid. To this end, the heat transfer liquid receives heat from the components of the powertrain and dissipates the heat, for example, in an air flow, in a second heat exchanger.

[0004] Integrating these two heat exchangers in a vehicle can be tricky, especially due to their volume when the two heat exchangers are offset from each other in order to receive the same air flow simultaneously. To limit the volume, the two exchangers can also be aligned in the direction of the air flow so that they are successively passed through by the same air flow. However, when the air passes through the upstream exchanger, the heating of the air tends to impair the efficiency of the downstream exchanger.

[0005] The present invention aims to propose solutions that are easier to integrate due to being more compact and that provide improved thermodynamic performance. Summary of the Invention

[0006] To this end, the present invention proposes a heat exchanger for a motor vehicle, comprising:

[0007] - a first heat exchange section configured to allow heat exchange between a refrigerant and an air flow,

[0008] The first heat exchange section includes a first bundle of tubes forming a set of refrigerant circulation channels configured to be arranged in the air flow,

[0009] - a second heat exchange section configured to allow heat exchange between a heat transfer liquid and an air flow,

[0010] The second heat exchange section includes a second bundle of tubes forming a set of heat transfer liquid circulation channels configured to be arranged in the air flow,

[0011] Among them, the tubes in the first bundle have a U shape, which includes a first branch and a second branch connected by a base,

[0012] wherein the first branch is upstream of the second branch in the flow direction of the air flow, and

[0013] wherein the second bundle of tubes is arranged between the first branch and the second branch of the first bundle of tubes in the flow direction of the air flow.

[0014] The U shape of the tubes in the first bundle allows increasing the length of the heat exchange involved in the first heat exchange section while limiting the front surface area of the exchanger. Since the second heat exchange section is arranged in the free volume formed by the intervals between the branches of each U-shaped tube in the first bundle, the presence of the second heat exchange section does not change the external volume of the heat exchanger. Therefore, the heat exchanger has a very compact shape.

[0015] In addition, for the flow of the air flow, the first branch of the tube is upstream of the second heat exchange section, and the second heat exchange section itself is upstream of the second branch of the tube in the first heat exchange section. Therefore, each tube or part of the tube receives an air flow whose temperature is adapted to the temperature of the fluid flowing inside. In other words, the first branch of the first heat exchange section receives a fresh ambient air flow that has not been heated by passing through the heat exchanger, which improves its efficiency. The air flow leaving the first branch of the first heat exchange section has a low enough temperature to ensure good exchange efficiency with the second heat exchange section. Similarly, the air flow heated by passing through the second heat exchange section still has a low enough temperature to ensure good exchange efficiency with the refrigerant flowing in the second branch of the first heat exchange section. Therefore, for a given volume, the efficiency of the heat exchanger is optimized. In addition, due to the proposed arrangement, any limitation regarding the maximum temperature of the heat transfer liquid at the outlet of the second heat exchange section can be met.

[0016] The functions listed in the following paragraphs can be implemented independently of each other or in any technically possible combination:

[0017] According to one aspect of the proposed heat exchanger, the second bundle of tubes is located downstream of the first branch tube of the tubes in the first bundle and upstream of the second branch of the tubes in the first bundle.

[0018] According to an operating mode of the heat exchanger, the first heat exchange section operates as a condenser for the refrigerant.

[0019] According to an operating mode of the exchanger, the refrigerant flowing in the first heat exchange section releases heat to the air flow.

[0020] According to this operating mode, the refrigerant flows from the second branch of the tube to the first branch of the tube.

[0021] According to another operating mode of the heat exchanger, the first heat exchange section operates as an evaporator of the refrigerant.

[0022] According to one operating mode, the refrigerant flowing through the first heat exchange section receives heat from the air stream.

[0023] According to this operating mode, the refrigerant flows from the first branch of the tube to the second branch of the tube.

[0024] According to an exemplary embodiment of the heat exchanger, the air stream is the air stream outside the vehicle.

[0025] According to another exemplary embodiment of the heat exchanger, the air stream is the air stream inside the vehicle.

[0026] In one application of the heat exchanger, the refrigerant can be a chemical fluid, such as R1234yf or R134a.

[0027] In another application of the heat exchanger, the refrigerant can be R744 or R290.

[0028] The heat transfer liquid can be a mixture of water and ethylene glycol.

[0029] According to one aspect of the heat exchanger, each tube in the first bundle of tubes extends in a plane.

[0030] The tubes in the first bundle of tubes are arranged in parallel planes.

[0031] The tubes in the first bundle of tubes are aligned in a direction perpendicular to the plane of the tubes.

[0032] According to an embodiment of the heat exchanger, the second bundle of tubes extends between two parallel planes that are perpendicular to the plane of the tubes of the first bundle.

[0033] The heat exchanger thus has a compact shape, and the second heat exchange section fills the free space between all the first branches of the tubes of the first heat exchange section and all the second branches of the tubes.

[0034] The first branches of the tubes in the first bundle of tubes are connected to the first branches of adjacent tubes by a first set of fins.

[0035] The second branches of the tubes in the first bundle of tubes are connected to the second branches of adjacent tubes by a second set of fins.

[0036] The fins improve the heat transfer between the air stream and the refrigerant flowing through the tubes in the first heat exchange section.

[0037] The fins have slots for the air stream to pass through.

[0038] According to one aspect of the heat exchanger, the bases of the tubes in the first bundle of tubes are spaced apart from the bases of adjacent tubes.

[0039] When the first heat exchange section operates as an evaporator and the external temperature is below 0 °C or close to 0 °C, ice forms on at least a portion of the tubes in the tube bundle. When the ice melts, water flows down the tubes to the base of the tubes. The gap between two adjacent tubes allows the water to flow and prevents water from accumulating at the base of the tubes. Thus, the risk of frosting and restructuring on the first heat exchange section is reduced.

[0040] The outer periphery of the tubes in the first tube bundle has an oval cross-section.

[0041] The tubes in the first tube bundle are, for example, microchannel tubes.

[0042] According to one embodiment of the heat exchanger, the outer periphery of the tubes in the first tube bundle has an oval cross-section defining a major axis and a minor axis, and the major axis of the first branch of the tube is parallel to the air flow.

[0043] According to one embodiment, the major axis of the second branch of the tube is parallel to the air flow.

[0044] The tubes in the first tube bundle can be twisted near the junction between the first branch and the base.

[0045] Similarly, the tubes in the first tube bundle can be twisted near the junction between the base and the second branch.

[0046] In this embodiment, the major axis of the base of the tube is perpendicular to the air flow.

[0047] According to an exemplary embodiment of the heat exchanger, when the heat exchanger is in its nominal position installed in a vehicle, the base of the tubes in the first tube bundle defines the lower side of the heat exchanger.

[0048] According to this exemplary embodiment of the heat exchanger, when the heat exchanger is in its nominal position installed in a vehicle, the first branch of the tubes in the first tube bundle extends along a vertical axis.

[0049] When the ice deposits accumulated on the surfaces of the first heat exchange section and / or the second heat exchange section melt, this configuration facilitates the discharge of the water generated by the defrosting of the heat exchanger. Specifically, the liquid water can flow along the tubes without encountering any obstacles that could cause it to be retained.

[0050] According to another exemplary embodiment, when the heat exchanger is in its nominal position installed in a vehicle, the base of the tubes of the first bundle defines the lateral side of the heat exchanger.

[0051] According to this exemplary embodiment of the heat exchanger, when the heat exchanger is in its nominal position installed in a vehicle, the first branch of the tubes in the first tube bundle extends along a horizontal axis.

[0052] This configuration makes it possible to prevent any corrosion of the lowest part of the heat exchanger due to the accumulation of moisture. In addition, when the heat exchanger has a low height and a large width, this configuration makes it possible to limit the number of tubes required. When the exchanger is nominally installed in a vehicle, the height is understood as the dimension along the vertical axis, and the width is understood as the dimension along the transverse axis of the vehicle. This helps to manufacture an exchanger for applications with a low front end of the vehicle.

[0053] The first ends of the tubes in the first bundle lead to a first distributor configured to distribute refrigerant between all the tubes in the first bundle.

[0054] The first distributor extends transversely to the axes of the tubes in the first bundle.

[0055] The first distributor has a cylindrical shape.

[0056] The first distributor includes a refrigerant inlet.

[0057] The second ends of the tubes in the first bundle lead to a first manifold configured to collect refrigerant from all the tubes in the first bundle.

[0058] The first manifold extends transversely to the axes of the tubes in the first bundle.

[0059] The first manifold has a cylindrical shape.

[0060] The first manifold includes a refrigerant outlet.

[0061] The first manifold and the first distributor extend in a parallel direction.

[0062] The tubes in the first bundle are identical.

[0063] According to one embodiment, the refrigerant inlet and the refrigerant outlet are opposite to each other in a direction perpendicular to the axis of the first distributor.

[0064] According to an example embodiment of the heat exchanger, when the heat exchanger is in its nominal position installed in a vehicle, the first distributor is downstream of the first manifold in the direction of the air flow.

[0065] In another example embodiment of the heat exchanger, when the heat exchanger is in its nominal position installed in a vehicle, the first manifold is downstream of the first distributor in the direction of the air flow.

[0066] According to one embodiment of the heat exchanger, the first branch of the tubes in the first bundle and the second branch of the tubes in the first bundle have the same length. The length of the first branch and the second branch of the tubes in the first bundle is, for example, between 300 millimeters and 600 millimeters.

[0067] According to another embodiment of the heat exchanger, the length of the first branch of the tubes in the first tube bundle is less than the length of the second branch of the tubes in the first tube bundle.

[0068] Thus, the amount of material used to manufacture the first tube bundle is reduced. In addition, the portion of the tubes in the second tube bundle directly receives the air flow F, and no tube of the first bundle is located upstream. The production cost of the exchanger can be reduced without compromising its efficiency.

[0069] In this case, the length of the first branch of the tubes in the first tube bundle is, for example, between 100 mm and 300 mm.

[0070] The length of the second branch of the tubes in the first tube bundle is, for example, between 300 mm and 600 mm.

[0071] According to one embodiment, the tubes in the second tube bundle extend transversely to the tubes in the first tube bundle.

[0072] The tubes in the second tube bundle are parallel to each other.

[0073] The tubes in the second tube bundle are identical.

[0074] The second heat exchange section has a generally parallelepiped shape.

[0075] The first ends of the tubes in the second tube bundle lead to a second distributor configured to distribute the heat transfer liquid between all the tubes in the second tube bundle.

[0076] The second distributor extends transversely to the axes of the tubes in the second tube bundle.

[0077] The second distributor includes a heat transfer liquid inlet.

[0078] The second ends of the tubes in the second tube bundle lead to a second manifold configured to collect the heat transfer liquid from all the tubes in the second tube bundle.

[0079] The second manifold extends transversely to the axes of the tubes in the second tube bundle.

[0080] The second manifold includes a heat transfer liquid outlet.

[0081] The perimeter of the tubes in the second tube bundle has an oval cross-section.

[0082] According to one embodiment, the heat exchanger includes a support arranged between at least a portion of the tubes in the second tube bundle and the base of at least a portion of the tubes in the first tube bundle.

[0083] The heat exchanger may include a support connecting the second heat exchange section to the base of the tubes in the first tube bundle.

[0084] The support member provides mechanical support for the base of the tubes of the first heat exchange section relative to the second heat exchange section, which helps to attenuate the propagation of vehicle vibrations in the tubes of the first heat exchange section.

[0085] According to an exemplary embodiment of the heat exchanger, the thermal conductivity of the support member is lower than that of the tubes of the first bundle, preferably lower than 10% of the thermal conductivity of the tubes of the first bundle.

[0086] Thus, the support member thermally insulates the base of the tubes of the first heat exchange section from the second heat exchange section, preventing the formation of a thermal bridge.

[0087] The support member is made of, for example, plastic, in particular glass fiber-reinforced polyamide (e.g., PA6 reinforced with 30% glass fiber) or glass fiber-reinforced polypropylene (e.g., PP reinforced with 30% glass fiber).

[0088] The support member can rigidly fix the second heat exchange section to the base of the tubes in the first bundle.

[0089] According to an exemplary embodiment, the second heat exchange section includes a face disposed opposite to the base of the tubes in the first bundle, and the support member connects the base of the tubes in the first bundle to the opposite face.

[0090] According to an embodiment of the heat exchanger, the support member includes a sealing wall that connects the second heat exchange section to the base of the tubes in the first bundle, thereby preventing air flow from circulating between the second heat exchange section and the base of the tubes in the first bundle.

[0091] The sealing wall prevents air flow from circulating in the space between the base of the tubes of the first bundle and the face of the second heat exchange section that is positioned opposite. Thus, the sealing wall prevents a portion of the air flow F from leaving the exchanger without exchanging heat with the second heat exchange section.

[0092] The support member can have a trapezoidal cross-section.

[0093] The smaller base of the trapezoid is opposite to the second heat exchange section. The larger base is opposite to the base of the tubes in the first bundle.

[0094] Thus, the support member directs the air flow flowing near the base of the tubes in the first bundle towards the second heat exchange section. In addition, the water generated during the defrosting phase can also be directed to the bottom of the exchanger, which promotes the drainage of this water.

[0095] According to an exemplary embodiment, the support member is rigidly fixed to the base of each tube in the first bundle.

[0096] The support member provides mechanical support for the tubes relative to each other, which limits the amplitude of vibrations. This improves the mechanical strength of the heat exchanger.

[0097] The support member, for example, is overmolded on the base of the tube in the first tube bundle.

[0098] Alternatively, the surface of the second heat exchange section can be rigidly fixed to the base of the tube of the first heat exchange section, in particular by brazing.

[0099] According to an alternative embodiment, the tubes in the second tube bundle extend parallel to the first branch of the tubes in the first tube bundle.

[0100] This arrangement allows the second manifold or the second distributor to be arranged opposite the base of the tubes in the first tube bundle. Accordingly, the base of the refrigerant tubes can be attached to the second manifold or the second distributor. Thus, the support for rigidly fixing the second heat exchange section to the base of the tubes in the first tube bundle is unnecessary.

[0101] Furthermore, one of the distributor and the manifold of the second tube bundle can be aligned with the upstream refrigerant manifold / distributor. Accordingly, the air flow through the heat exchanger is less disturbed, which improves the efficiency for a given volume. Description of the Drawings

[0102] Further features, details and advantages will become apparent by reading the following detailed description and studying the drawings, in which:

[0103] Figure 1 is a schematic side cross-sectional view of a heat exchanger according to a first embodiment of the present invention,

[0104] Figure 2 is Figure 1 a schematic end view of the heat exchanger,

[0105] Figure 3 is a schematic side cross-sectional view of a heat exchanger according to a second embodiment of the present invention,

[0106] Figure 4 is a schematic detailed side cross-sectional view of a variant of the heat exchanger according to the present invention,

[0107] Figure 5 is a schematic partial perspective view of the heat exchanger according to the present invention,

[0108] Figure 6 is a schematic partial top view of three variants of the heat exchanger according to the present invention,

[0109] Figure 7 is a schematic partial view of the tube in the first tube bundle of the heat exchanger according to the present invention. Detailed Description

[0110] For ease of reading the figures, the various elements are not necessarily shown to scale. In these figures, identical elements have the same reference numerals. Some elements or parameters may be indexed, that is to say designated as for example a first element or a second element, or indeed a first parameter and a second parameter etc. The purpose of such indexing is to distinguish similar but not identical elements or parameters. Such indexing does not imply that one element or parameter is prior to another, and the names can be interchanged.

[0111] In the following description, the expression "a first element upstream of a second element" means that, with respect to the direction of flow or travel of a fluid, the first element is located before the second element. Similarly, the expression "a first element downstream of a second element" means that, with respect to the said direction of flow or travel of the fluid, the first element is located after the second element.

[0112] The expression "a second element is placed between a first element and a third element" means that the shortest path from the first element to the third element passes through the second element.

[0113] When it is specified that a subsystem has a given element, this does not exclude the presence of other elements in the subsystem.

[0114] The term "exchanger" is equivalent to the term "heat exchanger".

[0115] The heat exchanger 50 described below can be integrated in a thermal regulation system. The thermal regulation system includes a refrigerant circuit and a heat transfer liquid circuit. The refrigerant circuit forms a closed circuit in which the refrigerant can circulate. When the refrigerant circuit is in a nominal operating state, that is to say without defects or leaks, the refrigerant circuit is fluid-tight. Similarly, the heat transfer liquid circuit forms a closed and fluid-tight circuit in which the heat transfer liquid can circulate.

[0116] The thermal regulation system includes a compressor that places the refrigerant in a high-pressure and high-temperature state. The high-pressure, high-temperature refrigerant can be sent to a first heat exchange section 1 of the heat exchanger 50, where the refrigerant releases heat to the air flow F. The heat exchanger 50 is arranged for example at the front end of a vehicle and receives the air flow F outside the vehicle interior, which is especially generated by the forward movement of the vehicle. The cooled refrigerant can then pass through an expansion valve and become a low-pressure refrigerant, and then evaporate in a second heat exchanger. The second heat exchanger is located for example in the HVAC (heating, ventilation and air conditioning) equipment of the vehicle. Thus, the second heat exchanger makes it possible to cool the vehicle interior. Alternatively, the second heat exchanger can be a cooling exchanger thermally coupled to an electrical energy storage battery. Thus, the second exchanger allows the battery to be cooled, especially during the fast charging phase.

[0117] According to other usage modes of the thermal regulation system, the heat exchanger 50 can receive low-pressure refrigerant and perform evaporation of the refrigerant. The heating or dehumidification phases of the air inside the vehicle correspond to these usage modes.

[0118] The heat transfer fluid circuit of the thermal regulation system makes it possible to cool the components of the electric powertrain of the vehicle. The components of the electric powertrain can include an electrical energy storage battery, or an electronic module for controlling the electric drive motor of the vehicle, or the motor itself. The heat transfer fluid thus receives heat from the components of the powertrain, and this heat is dissipated in the second heat exchange section 2 of the exchanger 50.

[0119] Figure 1 The heat exchanger 50 according to the first embodiment is shown. The heat exchanger 50 is, for example, a heat exchanger for a motor vehicle. In the various figures, the X-axis corresponds to the longitudinal axis of the vehicle, the Y-axis corresponds to the transverse axis, and the Z-axis corresponds to the vertical axis.

[0120] The heat exchanger 50 for a motor vehicle includes:

[0121] - A first heat exchange section 1 configured to allow heat exchange between the refrigerant and the air flow F,

[0122] The first heat exchange section 1 includes a first bundle 11 of tubes 3 forming a set of refrigerant circulation channels configured to be arranged in the air flow F,

[0123] - A second heat exchange section 2 configured to allow heat exchange between the heat transfer fluid and the air flow F,

[0124] The second heat exchange section includes a second bundle 12 of tubes 4 forming a set of heat transfer fluid circulation channels configured to be arranged in the air flow F.

[0125] The tubes 3 in the first bundle 11 have a U shape, which includes a first branch 5 and a second branch 7 connected by a base 6.

[0126] The first branch 5 is positioned upstream of the second branch 7 in the flow direction of the air flow F, and

[0127] The second bundle 12 of tubes is arranged between the first branch 5 and the second branch 7 of the tubes 3 in the first bundle 11 in the flow direction of the air flow F.

[0128] The U-shape of the tubes 3 in the first bundle 11 of tubes 3 enables an increase in the length of the heat exchange taking place in the first heat exchange section while limiting the front surface area of the exchanger 50. In addition, a part of the tubes forming the first branch 5 directly receives ambient air that has not been heated by another heat exchanger, which increases the efficiency of the heat exchange. The second heat exchange section 2 is arranged in the free volume formed by the spaces between the branches 5, 7 of each U-shaped tube 3 in the first bundle 11 of tubes. The presence of the second heat exchange section 2 does not change the external volume of the heat exchanger 50. The heat exchanger 50 thus has a very compact and thermally optimized shape.

[0129] Furthermore, the first branch 5 of the tube 3 is positioned upstream of the second heat exchange section 2 with respect to the flow of the air stream F, and the second heat exchange section 2 itself is positioned upstream of the second branch 7 of the tube 3 of the first heat exchange section 1. Thus, each tube or part of a tube receives an air stream whose temperature is adapted to the temperature of the fluid flowing in that tube. In other words, the first branch 5 of the first heat exchange section 1 receives a fresh ambient air stream that has not been heated by passing through the heat exchanger, which increases its heat exchange efficiency. The air stream leaving the first branch 5 of the first heat exchange section 1 has a low enough temperature to ensure good exchange efficiency with the fluid flowing in the second heat exchange section 2. Similarly, the air stream heated by passing through the second heat exchange section 2 still has a low enough temperature to ensure good exchange efficiency with the refrigerant flowing in the second branch 7 of the first heat exchange section 1. Thus, for a given volume, the efficiency of the heat exchanger 50 is optimized.

[0130] The fact that the tubes of the first bundle 11 have a U-shape is understood to mean that the tubes include a first straight portion called the first branch 5, which is fluidly connected by an intermediate portion called the base 6 to a second straight portion called the second branch 7. The first branch 5 and the second branch 7 extend parallel and opposite to each other. The intermediate portion 6 extends transversely to the first branch 5 and the second branch 7. In this case, the intermediate portion is straight. The first branch 5, the second branch 7, and the intermediate portion 6 are arranged in the same plane.

[0131] According to a variant not shown, the intermediate portion may have a curved shape.

[0132] The second bundle 12 of tubes is located downstream of the first branch of the tubes 3 of the first bundle 11 and upstream of the second branch 7 of the tubes 3 of the first bundle 11.

[0133] According to one operating mode of the heat exchanger 50, the first heat exchange section 1 operates as a condenser for the refrigerant.

[0134] According to this operating mode of the exchanger 50, the refrigerant flowing in the first heat exchange section 1 releases heat to the air flow F. This is also the case when the refrigerant used is in a supercritical state. In this case, the exchanger 50 operates as a cooler for the refrigerant without any condensation. For example, this operation occurs when the refrigerant used is R744.

[0135] According to this operating mode as a condenser and / or cooler, the refrigerant flows from the second branch 7 of the tube 3 to the first branch 5 of the tube 3. In other words, the hottest refrigerant reaches the first heat exchange section 1 through the tube part that is the most downstream with respect to the flow of the air flow F.

[0136] According to another operating mode of the heat exchanger 50, the first heat exchange section 1 operates as an evaporator for the refrigerant.

[0137] According to this operating mode, the refrigerant flowing in the first heat exchange section 1 receives heat from the air flow F. This operating mode corresponds, for example, to the heat pump mode.

[0138] According to this operating mode, the refrigerant flows from the first branch 5 of the tube 3 to the second branch 7 of the tube 3. In other words, the refrigerant reaches the first heat exchange section 1 through the tube part that is the most upstream with respect to the flow of the air flow F. Preferably, the flow direction of the refrigerant is reversed according to whether the exchanger 50 operates as a condenser or an evaporator. This reversal of the flow direction is optional depending on the operating mode of using the heat exchanger.

[0139] According to an exemplary embodiment of the heat exchanger 50, the air flow F is an air flow outside the vehicle. In this case, the exchanger 50 is arranged, for example, at the front end of the vehicle, behind the radiator grille.

[0140] According to another exemplary embodiment of the heat exchanger 50, the air flow F is an air flow inside the vehicle. The exchanger 50 is then arranged in the heating, ventilation, and / or air conditioning equipment of the vehicle.

[0141] In one application of the heat exchanger 50, the refrigerant can be a chemical fluid, such as R1234yf or R134a. In another application of the heat exchanger, the refrigerant can be R744 or R290.

[0142] The refrigerant flows in parallel in the tube 3 of the first bundle of 11 tubes.

[0143] Similarly, the heat transfer liquid flows in parallel in the tube 4 of the second bundle of 12 tubes. The heat transfer liquid can be a mixture of water and ethylene glycol.

[0144] Figure 5The first heat exchange section 1 and the second heat exchange section 2 are shown separately. In other words, the second heat exchange section 2 and the first heat exchange section 1 have been moved along the transverse axis Y for easier differentiation. As schematically shown in this figure, each tube 3 in the first bundle 11 of tubes extends in the plane P1.

[0145] The tubes 3 in the first bundle 11 of tubes are arranged in parallel planes. In Figure 5 , nine tubes 3 are depicted. More generally, the first bundle 11 can include any number of tubes 3.

[0146] The tubes 3 in the first bundle 11 of tubes are aligned in the direction D perpendicular to the tube plane.

[0147] The tubes 3 of the first bundle 11 can in particular be made of aluminum or copper. Similarly, the tubes 4 of the second bundle 12 can be made of aluminum or copper, for example.

[0148] According to the example shown, the tubes 4 of the second bundle 12 extend between two parallel planes P2, P2', which are perpendicular to the plane of the tubes 3 of the first bundle 1. The plane P2 is shown in Figure 6 , Figure 6 which is a schematic top view of the heat exchanger 50.

[0149] The heat exchanger 50 thus has a compact shape, and the second heat exchange section 2 fills the free space between all the first branches 5 of the tubes 3 of the first heat exchange section 1 and all the second branches 7 of the tubes 3.

[0150] In particular, as shown in Figure 2 , the first branches 5 of the tubes 3 in the first bundle 11 of tubes are connected to the first branches of adjacent tubes by a first group of fins 23. In other words, two adjacent tubes in the first bundle 11 of tubes are connected by a group of fins 23.

[0151] Similarly, the second branches 7 of the tubes 3 in the first bundle 11 of tubes are connected to the second branches of adjacent tubes by a second group of fins 24.

[0152] The fins 23, 24 improve the heat transfer between the air flow F and the refrigerant flowing in the tubes 3 of the first heat exchange section 1.

[0153] The fins 23, 24 have slots 25 for the air flow F to pass through. The slots 25 improve the heat transfer between the air flow F and the fins 23, 24.

[0154] Similarly, the tubes 4 in the second bundle 12 are connected to adjacent tubes by a group of fins 32. These fins improve the heat transfer between the air flow F and the heat transfer liquid flowing in the second heat exchange section 2. In Figure 2 , only a part of the tubes in the first bundle 11 is shown to make a part of the second heat exchange section 2 visible.

[0155] The base 6 of the tube 3 in the first bundle of 11 tubes is spaced apart from the base of the adjacent tube 3. In other words, the bases of the tubes 3 in the first bundle of 11 tubes are spaced apart from each other. The free space between the bases 6 of two adjacent tubes can be constant.

[0156] When the first heat exchange section 1 operates as an evaporator and the external temperature is below 0 °C or close to 0 °C, ice forms on at least a part of the tubes in the bundle of 11 tubes. When the ice melts, water flows along the tube 3 to the base 6 of the tube. The gap between two adjacent tubes 3 allows the water to flow and prevents water from accumulating at the base 6 of the tube. Thus, the risk of frost reformation on the first heat exchange section 1 is reduced.

[0157] The outer periphery of the tube 3 in the first bundle of 11 tubes has an oval cross-section. The tube 3 in the first bundle of 11 tubes is, for example, a microchannel tube. In other words, each tube 3 includes a plurality of parallel channels. The microchannel tube is formed by extrusion and then shaped to obtain the desired U-shape. The outer periphery of the tube 3 in the first bundle of 11 tubes has an oval cross-section, defining a major axis a and a minor axis b. The major axis a of the first branch 5 of the tube is parallel to the air flow F. The major axis of the second branch 7 of the tube 3 is also parallel to the air flow F. Figure 7 is a schematic detailed view of the external shape of the tube 3. In this figure, the microchannels are not shown.

[0158] The tube 3 in the first bundle of 11 tubes can be twisted near the joint 35 between the first branch 5 and the base 6. Similarly, the tube 3 in the first bundle of 11 tubes can be twisted near the joint 36 between the base 6 and the second branch 7. In other words, in the region of the joint 35 between the first branch 5 and the base 6, the major axis a of the cross-section of the tube 3 gradually rotates 90° around the extension axis D5 of the first branch 5 of the tube 3. This deformation of the tube allows a U-shape to be produced without excessive deformation of the material of the tube.

[0159] In this embodiment, the major axis a of the base 6 of the tube 3 is perpendicular to the air flow F.

[0160] According to an exemplary embodiment of the heat exchanger 50, when the heat exchanger 50 is in the nominal position installed in a vehicle, the base 6 of the tube 3 in the first bundle of 11 tubes defines the lower side of the heat exchanger 50. In other words, the base 6 extends in a plane parallel to the plane X, Y. The various figures show the exchanger 50 oriented in this way.

[0161] When the heat exchanger 50 is in the nominal position installed in a vehicle, the first branch 5 of the tube 3 in the first bundle of 11 tubes extends along the vertical axis Z.

[0162] When the ice deposits accumulated on the surface of the first heat exchange section melt, this configuration facilitates the discharge of the water generated by defrosting the heat exchanger. Specifically, the liquid water can flow along the tube without encountering any obstacles that could cause it to be retained.

[0163] According to another exemplary embodiment (not shown), when the heat exchanger 50 is in its nominal position mounted in the vehicle, the first branch 5 of the tube 3 in the first bundle 11 extends along a horizontal axis. This horizontal axis is, for example, the transverse axis Y of the vehicle.

[0164] When the heat exchanger 50 is in its nominal position mounted in the vehicle, the base 6 of the tube 3 in the first bundle 11 defines the lateral side of the heat exchanger 50. In other words, the base 6 then extends in a plane parallel to the plane Y, Z. This configuration is particularly suitable for applications where the vehicle has a low and wide front end.

[0165] As Figure 5 shown, the first end 15 of the tube 3 in the first bundle 11 of tubes leads to a first distributor 9, which is configured to distribute the refrigerant between all the tubes 3 in the first bundle 11 of tubes. The first distributor 9 extends transversely to the axis of the tubes 3 in the first bundle 11 of tubes.

[0166] The first distributor 9 has, for example, a cylindrical shape. The first distributor 9 includes a refrigerant inlet 13.

[0167] The second end 16 of the tube 3 in the first bundle 11 of tubes leads to a first manifold 10, which is configured to collect the refrigerant from all the tubes 3 in the first bundle 11 of tubes. The first manifold 10 extends transversely to the axis of the tubes 3 in the first bundle 11 of tubes.

[0168] The first manifold 10 has, for example, a cylindrical shape. The first manifold 10 includes a refrigerant outlet 14.

[0169] The first manifold 10 and the first distributor 9 extend in a parallel direction.

[0170] The tube 3 is sealingly connected to the first distributor 9 at its first end 15. Similarly, the tube 3 is sealingly connected to the first manifold 10 at its second end 16. The tube 3 is, for example, brazed to the first distributor 9 and the first manifold 10.

[0171] In the example shown, and in particular in Figure 5 it, the tubes 3 in the first bundle 11 of tubes are identical.

[0172] The refrigerant inlet 13 and the refrigerant outlet 14 can be arranged relative to each other in different ways. Figure 6 A number of possible configurations are schematically shown.

[0173] According to the example shown, the refrigerant inlet 13 and the refrigerant outlet 14 are opposite to each other in a direction perpendicular to the axis of the first distributor 9. In other words, the refrigerant inlet 13 and the outlet 14 are arranged on the same side edge of the exchanger 50.

[0174] According to a variant not shown, the refrigerant inlet 13 and the refrigerant outlet 14 may be arranged on opposite side edges along the axis of the first distributor 9.

[0175] The refrigerant inlet 13 and the refrigerant outlet 14 may also be arranged near the middle of the first distributor 9 and the first manifold 10 relative to their main extension directions. This arrangement enables the reduction of refrigerant pressure loss and the improvement of refrigerant distribution. Specifically, the distance between the refrigerant inlet and the farthest tube is thus reduced. The same applies to the distance between the refrigerant outlet and the farthest outlet.

[0176] Note that the refrigerant inlet 13 and the outlet 14 are not inherent limitations of the exchanger 50, but may vary according to the flow pattern of the refrigerant within the thermal regulation system in which the exchanger is integrated. In other words, the part corresponding to the refrigerant inlet 13 in one operating mode may become the refrigerant outlet 14 in another operating mode. Specifically, once the heat exchanger 50 has been integrated into the thermal regulation system, the flow direction of the refrigerant is controlled by a set of valves that can be selectively opened or closed. By controlling the various valves, the flow direction of the refrigerant in the first heat exchange section 1 can be reversed. Thus, the flow direction of the refrigerant can be changed according to the required operating mode, for example, in the condenser or evaporator mode.

[0177] According to Figure 6 the exemplary embodiment of the heat exchanger 50 shown in part A of

[0178] In Figure 6 another exemplary embodiment of the heat exchanger 50 schematically shown in part B of

[0179] In particular, as in Figure 1 and Figure 2In the first embodiment shown, the first branch 5 and the second branch 7 of the tube 3 of the first bundle 11 have substantially the same length. This length is, for example, between 300 millimeters and 600 millimeters. The tubes 4 of the second bundle 12 extend along the axis Z, along the entire length of the first branch 5 and the second branch 7. In other words, the entire second bundle 12 of tubes is arranged between the first branch 5 and the second branch 7 of the tubes 3 in the first bundle 11 in the flow direction of the air flow F.

[0180] Figure 3 A second embodiment of the heat exchanger 50 is shown. In this embodiment, the length L1 of the first branch 5 of the tube 3 in the first bundle 11 of tubes is less than the length L2 of the second branch 7 of the tube 3 in the first bundle 11 of tubes. In other words, only a part of the tubes 4 of the second heat exchange section 2 is opposite the first branch 5 of the tubes 3 of the first heat exchange section 1.

[0181] The amount of material used to manufacture the first bundle 11 of tubes is thus reduced. In addition, a part of the tubes 4 in the second bundle 12 directly receives the air flow F, and no tube of the first bundle 11 is located upstream. Therefore, this part of the tubes 4 is particularly effective in terms of heat exchange. The production cost of the exchanger 50 can be reduced without compromising its efficiency.

[0182] In this case, the length L1 of the first branch 5 of the tube 3 in the first bundle 11 of tubes is, for example, between 100 millimeters and 300 millimeters. The length L2 of the second branch 7 of the tube 3 in the first bundle 11 of tubes is, for example, between 300 millimeters and 600 millimeters.

[0183] According to the embodiment shown in the figure, the tubes 4 in the second bundle 12 extend transversely to the tubes 3 in the first bundle 11. The tubes 4 in the second bundle 12 are parallel to each other. The tubes 4 in the second bundle 12 are, for example, identical. As Figure 5 Schematically shown, the tubes 4 in the second bundle 12 extend along the transverse axis Y.

[0184] The second heat exchange section 2 has a substantially parallelepiped shape.

[0185] In the longitudinal direction X, there is a gap between the first branch 5 of the tubes 3 in the first bundle 11 and the tubes 4 in the second bundle 12. Similarly, in the same longitudinal direction X, there is a gap between the tubes 4 of the second bundle 12 and the second branch 7 of the tubes 3 of the first bundle 11.

[0186] The first ends 17 of the tubes 4 in the second bundle 12 lead to the second distributor 19, which is configured to distribute the heat transfer liquid between all the tubes 4 in the second bundle 12. The second distributor 19 extends transversely to the axis of the tubes 4 in the second bundle 12. The second distributor 19 includes a heat transfer liquid inlet 21.

[0187] The second end 18 of tube 4 in the second bundle of twelve tubes 12 leads to a second manifold 20, which is configured to collect the heat transfer liquid from all of the tubes 4 in the second bundle of twelve tubes 12. The second end of tube 4 and the second manifold 20 are Figure 2 not visible in [[]], as they are arranged behind the first branch 5 of tube 3 shown.

[0188] The tubes 4 in the second bundle of twelve tubes 12 are sealingly connected at their first ends 17 to a second distributor 19. Similarly, the tubes 4 in the second bundle of twelve tubes 12 are sealingly connected at their second ends 18 to the second manifold 20. The tubes 4 in the second bundle of twelve tubes 12 are, for example, brazed to the second distributor 19 and the second manifold 20.

[0189] The second manifold 20 extends transversely to the axis of the tubes 4 in the second bundle of twelve tubes 12. The second manifold 20 includes a heat transfer liquid outlet 22. The second manifold 20 and the second distributor 19 extend along a vertical axis Z.

[0190] According to various examples of the embodiment, the relative positions of the heat transfer liquid inlet 21 and the outlet 22 can vary. In Figure 5 Figure 2 Figure 6 in the example of part C of [[[]]], the heat transfer liquid inlet 21 and the heat transfer liquid outlet 22 are arranged on opposite lateral sides of the heat exchanger 50. In Figure 6 in the examples of part A and part B of [[[]]], the inlet 21 and the outlet 22 are on the same lateral side. The flow of the heat transfer liquid in the manifolds and distributors is adjusted accordingly.

[0191] The outer periphery of the tubes 4 in the second bundle of twelve tubes 12 has an oval cross-section.

[0192] Figure 4 An alternative embodiment is shown, in which the heat exchanger 50 includes a support 30, which is arranged between the bases 6 of at least a part of the tubes 4 in the second bundle of twelve tubes 12 and at least a part of the tubes 3 in the first bundle of eleven tubes 11.

[0193] In the example shown, the heat exchanger 50 includes a support 30, which connects the second heat exchange section 2 to the base 6 of the tubes 3 in the first bundle of eleven tubes 11.

[0194] The support 30 provides mechanical support for the base 6 of the tubes 3 in the first heat exchange section 1 relative to the second heat exchange section 2, which helps to attenuate the propagation of vehicle vibrations in the tubes 3 in the first heat exchange section 1.

[0195] The thermal conductivity of the support 30 is lower than the thermal conductivity of the tubes 3 in the first bundle of eleven tubes 11, preferably lower than 10% of the thermal conductivity of the tubes 3 in the first bundle of eleven tubes 11.

[0196] Thus, the support 30 thermally insulates the base 6 of the tubes 3 in the first heat exchange section 1 from the second heat exchange section, preventing the formation of a thermal bridge.

[0197] The support member 30 is made of, for example, plastic, in particular glass fiber-reinforced polyamide (such as PA6 reinforced with 30% glass fiber) or glass fiber-reinforced polypropylene (such as PP reinforced with 30% glass fiber).

[0198] The support member 30 can rigidly fix the second heat exchange section 2 to the base 6 of the tube 3 in the first bundle 11 of tubes.

[0199] In Figure 6 In the illustrated example, the second heat exchange section 2 includes a face 26 disposed opposite to the base 6 of the tube 3 in the first bundle 11 of tubes, and the support member 30 connects the base 6 of the tube 3 in the first bundle 11 of tubes to the oppositely disposed face 26.

[0200] In this case, the support member 30 includes a sealing wall 27 that connects the second heat exchange section 2 to the base 6 of the tube 3 in the first bundle 11 of tubes, thereby preventing the air flow F from flowing between the second heat exchange section 2 and the base 6 of the tube 3 in the first bundle 11 of tubes.

[0201] The sealing wall 27 prevents the air flow from flowing in the space between the base of the tube 3 in the first bundle 11 and the face 26 of the second heat exchange section positioned opposite. Therefore, the sealing wall 27 prevents a part of the air flow F from leaving the exchanger 1 without exchanging heat with the second heat exchange section 2.

[0202] In this case, the support member 30 has a trapezoidal cross-section. The small base 28 of the trapezoid is opposite to the second heat exchange section 2. The large base 29 is opposite to the base 6 of the tube 3 in the first bundle 11 of tubes.

[0203] Therefore, the support member 30 guides the air flow F flowing near the base 6 of the tube 3 in the first bundle 11 of tubes to the second heat exchange section 2. In addition, the water generated during the defrosting phase can also be guided by the sealing wall 27 to the bottom of the exchanger 50, which facilitates the discharge of this water.

[0204] According to an example of the embodiment, the support member 30 is rigidly fixed to the base 6 of each tube 3 in the first bundle 11 of tubes.

[0205] The support member 30 provides mechanical support for the tubes 3 relative to each other, which limits the amplitude of vibration. This improves the mechanical strength of the heat exchanger 50.

[0206] The support member 30 is, for example, overmolded on the base 6 of the tube 3 in the first bundle 11 of tubes.

[0207] According to a variant not shown, the face 26 of the second heat exchange section 2 can be rigidly fixed to the base 6 of the tubes 3 of the first heat exchange section 1, in particular by brazing. In this case, there is no support 30. There is no gap along the axis Z between the face 26 of the second heat exchange section 2 and the base 6 of the tubes 3 of the first heat exchange section 1.

[0208] According to another alternative embodiment, the tubes 4 in the second bundle 12 of tubes are parallel to the first branch 5 of the tubes 3 in the first bundle 11 of tubes.

[0209] This arrangement allows the second manifold 20 or the second distributor 19 to be arranged opposite the base 6 of the tubes 4 in the first bundle 11 of tubes. Thus, the base 6 of the refrigerant tubes can be attached to the second manifold 20 or the second distributor 19 in order to provide support for the U-shaped tubes in the bundle 11 of tubes of the first heat exchange section 1.

[0210] Since the tubes 3 of the first bundle 11 of refrigerant tubes can be horizontal or vertical, and the tubes 4 of the second bundle 12 of heat transfer liquid tubes can also be horizontal or vertical, four arrangements are possible.

Claims

1. A heat exchanger (50) for a motor vehicle, comprising: - A first heat exchange section (1) configured to allow heat exchange between a refrigerant and an air flow (F), The first heat exchange section (1) includes a first bundle (11) of tubes (3) forming a set of refrigerant flow channels configured to be arranged in the air flow (F), - A second heat exchange section (2) configured to allow heat exchange between a heat transfer liquid and the air flow (F), The second heat exchange section includes a second bundle (12) of tubes (4) forming a set of heat transfer liquid flow channels configured to be arranged in the air flow (F), Wherein, the tubes (3) in the first bundle (11) have a U shape, the U shape includes a first branch (5) and a second branch (7) connected by a base (6), Wherein, the first branch (5) is positioned upstream of the second branch (7) in the flow direction of the air flow (F), and Wherein, the second bundle (12) of tubes is arranged between the first branch (5) and the second branch (7) of the tubes (3) in the first bundle (11) in the flow direction of the air flow (F).

2. The heat exchanger (50) according to claim 1, wherein, Each tube (3) in the first bundle (11) extends in a plane, Wherein, the tubes (3) in the first bundle (11) are arranged in parallel planes, and Wherein, the tubes (3) in the first bundle (11) are aligned in a direction (D) perpendicular to the plane of the tubes.

3. The heat exchanger (50) according to claim 2, wherein, The second bundle (12) of tubes (4) extends between two parallel planes (P2, P2'), the two planes (P2, P2') being perpendicular to the plane of the tubes (3) of the first bundle (11).

4. The heat exchanger (50) according to any one of the preceding claims, wherein, The base (6) of the tubes (3) in the first bundle (11) is spaced apart from the bases of adjacent tubes (3).

5. The heat exchanger (50) according to any one of the preceding claims, wherein, The outer periphery of the tubes (3) in the first bundle (11) has an oval cross-section defining a major axis and a minor axis, wherein the major axis of the first branch (5) of the tube is parallel to the air flow (F), Wherein, the major axis of the second branch (7) of the tube (3) is parallel to the air flow (F), and Wherein, the major axis of the base (6) of the tube (3) is perpendicular to the air flow (F).

6. The heat exchanger (50) according to any one of the preceding claims, wherein, When the heat exchanger (50) is in its nominal position installed in a vehicle, the base (6) of the tubes (3) in the first bundle (11) defines the lower side of the heat exchanger (50), and Wherein, when the heat exchanger (50) is in its nominal position installed in a vehicle, the first branch (5) of the tubes (3) in the first bundle (11) extends along a vertical axis (Z).

7. The heat exchanger (50) according to any one of claims 1 to 6, wherein, When the heat exchanger (50) is in its nominal position installed in a vehicle, the base (6) of the tubes (3) in the first bundle (11) defines the lateral side of the heat exchanger (50), and Wherein, when the heat exchanger (50) is in its nominal position installed in a vehicle, the first branch (5) of the tubes (3) in the first bundle (11) extends along a horizontal axis.

8. The heat exchanger (50) according to any one of claims 1 to 7, wherein, The first end (15) of the tube (3) in the first bundle (11) of tubes leads to a first distributor (9) configured to distribute the refrigerant among all the tubes (3) in the first bundle (11) of tubes. wherein the second end (16) of the tube (3) in the first bundle (11) of tubes leads to a first manifold (10) configured to collect the refrigerant from all the tubes (3) in the first bundle (11) of tubes, and wherein when the heat exchanger (50) is in its nominal position installed in a vehicle, the first distributor (9) is positioned downstream of the first manifold (10) in the direction of flow of the air stream (F).

9. The heat exchanger (50) according to any one of claims 1 to 7, Among them, The first end (15) of the tube (3) in the first bundle (11) of tubes leads to a first distributor (9) configured to distribute the refrigerant among all the tubes (3) in the first bundle (11) of tubes. wherein the second end (16) of the tube (3) in the first bundle (11) of tubes leads to a first manifold (10) configured to collect the refrigerant from all the tubes (3) in the first bundle (11) of tubes, and wherein when the heat exchanger (50) is in its nominal position installed in a vehicle, the first manifold (10) is positioned downstream of the first distributor (9) in the direction of flow of the air stream (F).

10. The heat exchanger (50) according to any one of the preceding claims, wherein, The length (L1) of the first branch (5) of the tube (3) in the first bundle (11) of tubes is less than the length (L2) of the second branch (7) of the tube (3) in the first bundle (11) of tubes.

11. The heat exchanger (50) according to any one of the preceding claims, comprising a support (30) connecting the second heat exchange section (2) to the base (6) of the tube (3) in the first bundle (11) of tubes.

12. The heat exchanger (50) according to claim 11, wherein, The thermal conductivity of the support (30) is lower than the thermal conductivity of the tubes (3) of the first bundle (11), preferably less than 10% of the thermal conductivity of the tubes (3) of the first bundle (11).

13. The heat exchanger (50) according to claim 11 or 12, wherein, The support (30) includes a sealing wall (27) that connects the second heat exchange section (2) to the base (6) of the tube (3) in the first bundle (11) of tubes, thereby preventing the air stream (F) from flowing between the second heat exchange section (2) and the base (6) of the tube (3) in the first bundle (11) of tubes.

14. The heat exchanger (50) according to any one of claims 1 to 13, wherein, The tubes (4) in the second bundle (12) of tubes extend transversely to the tubes (3) in the first bundle (11) of tubes.

15. The heat exchanger (50) according to any one of claims 1 to 13, wherein, The tubes (4) in the second bundle (12) of tubes extend parallel to the first branch (5) of the tubes (3) in the first bundle (11) of tubes.

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