Centralized heat exchange system for motor vehicles

Abstract

The invention relates to a heat exchange system for a motor vehicle. The heat exchange system comprises: a hydraulic circuit (32); a closed loop (30) isolated from the hydraulic circuit (32) and having a compressor (34) adapted to compress a first heat transfer fluid in said closed loop, an expansion valve (36); the hydraulic circuit comprising a first heat exchanger (26) capable of ensuring a heat exchange with the environment (40) of the motor vehicle, a second heat exchanger (42) capable of ensuring a heat exchange with the passenger compartment (14), a third heat exchanger (44) thermally coupled to the closed loop, a first branch (48) connecting the first heat exchanger to the third heat exchanger; a fourth heat exchanger (46) thermally coupled to the closed loop (30), and a second branch (50) connecting the fourth heat exchanger to the second heat exchanger.Figure to be published with the abstract: Figure 2.

Description

Title of the invention: Centralized heat exchange system for a motor vehicle

[0001] The invention relates to air conditioning systems comprising a heat transfer fluid and a refrigerant fluid for a motor vehicle. The subject of the invention is an indirect heat exchange system without risk of contact between a refrigerant fluid and the air in the passenger compartment. The subject of the invention is also a motor vehicle.

[0002] Current motor vehicles, in particular electric vehicles with traction batteries, require fine management of the temperature of their various elements, both motors and batteries, in order to maintain optimal performance. At the same time, the regulation of the temperature of the passenger compartment has become a key element in terms of passenger comfort and the perceived quality of a vehicle.

[0003] Air conditioning systems use heat pump devices, comprising a refrigerant fluid absorbing excess calories from one compartment and transferring them to another compartment or to the outside. In some cases, the refrigerant circuit can transfer or receive heat via a heat exchange with a second circuit comprising a heat transfer fluid; such as water. Said second circuit can then be in contact with the element to be air conditioned.

[0004] Document FR3101020A1 describes a heat treatment system intended for a vehicle comprising at least one refrigerant circuit and a heat transfer fluid loop based on glycolated water, the circuit comprising two heat exchangers, the loop comprising a radiator carrying out a heat exchange with an outside air flow. The heat treatment system comprises a heat exchanger configured to implement a heat exchange between the refrigerant circulating in the refrigerant circuit and the heat transfer fluid circulating in the heat transfer fluid loop. This heat exchanger is interposed between the first heat exchanger and the second heat exchanger of the refrigerant circuit. The refrigerant circuit, however, remains in direct contact with the interior air flow intended to be sent into the passenger compartment via one of the heat exchangers.

[0005] New environmental regulations require the abandonment of refrigerants used until now for their good thermal performance, due to their high global warming potential or their composition using per- and polyfluoroalkyl substances (also referred to by the English term "per- and polyfluoroalkyl substances" and by the acronym "PFAS"), such as 1,1,1,2-tetrafluoroethane, also known as R-134a fluid, or 2,3,3,3-Tetrafluoropropene (R-1234yf).

[0006] Alternative fluids are known, having better environmental characteristics and good thermal performance. However, these fluids also have certain constraints conditioning their use in air conditioning systems. In the event of a leak in the cooling circuit, these fluids can become harmful to passengers.

[0007] The invention aims to address at least one of the problems or drawbacks encountered in the prior art. In particular, the invention aims to increase the safety of passengers in a motor vehicle. The invention also aims to optimize the level of safety and compliance with environmental standards of a heat exchange system of a motor vehicle.

[0008] According to a first aspect, the invention proposes a heat exchange system for a motor vehicle with a passenger compartment; the heat exchange system comprising: at least one hydraulic circuit; a closed loop cut off from the at least one hydraulic circuit and having a compressor adapted to compress a first heat transfer fluid in said closed loop, an expansion valve; the at least one hydraulic circuit comprising a first heat exchanger capable of ensuring a heat exchange with the environment of the motor vehicle, a second heat exchanger capable of ensuring a heat exchange with the passenger compartment, a third heat exchanger thermally coupled to the closed loop, a first branch connecting the first heat exchanger to the third heat exchanger;remarkable in that the at least one hydraulic circuit further comprises a fourth heat exchanger thermally coupled to the closed loop, and a second branch connecting the fourth heat exchanger to the second heat exchanger.;

[0009] The invention places a closed loop outside the passenger compartment, and isolates it from the hydraulic circuit communicating with the passenger compartment. This makes it possible to fill this loop with a heat transfer fluid that is incompatible with a passenger compartment. Therefore, the invention makes it possible to use fluids that comply with environmental standards.

[0010] Preferably, the closed loop comprises a first flammable heat transfer fluid.

[0011] Preferably, the first flammable heat transfer fluid comprises propane or difluoroethane.

[0012] Preferably, the at least one hydraulic circuit comprises a fifth heat exchanger capable of ensuring a heat exchange with the passenger compartment, a third branch connecting the third heat exchanger to the fifth heat exchanger.

[0013] Preferably, the at least one hydraulic circuit comprises a sixth heat exchanger thermally coupled to the closed loop, a fourth branch connecting the sixth heat exchanger to the first heat exchanger.

[0014] Preferably, the heat exchange system comprises an electric heating module of the sixth heat exchanger; more preferably, via a seventh branch.

[0015] Preferably, the at least one hydraulic circuit comprises a second heat transfer fluid which is different from the first heat transfer fluid.

[0016] Preferably, the second heat transfer fluid comprises a mixture of water and glycol.

[0017] Preferably, the first heat transfer fluid is a compressible gas.

[0018] Preferably, the closed loop is a cooling loop.

[0019] Preferably, the third heat exchanger is opposite the fourth heat exchanger and / or the sixth heat exchanger with respect to the compressor and the expander.

[0020] Preferably, the fourth heat exchanger and the sixth heat exchanger are between the compressor and the expander.

[0021] According to another aspect, the invention proposes a motor vehicle comprising a heat exchange system, a passenger compartment, a front compartment; remarkable in that the heat exchange system is in accordance with the invention.

[0022] Preferably, the motor vehicle further comprises an electric motor for driving the motor vehicle and an electric drive battery, the closed loop being in the front compartment.

[0023] Preferably, the at least one hydraulic circuit comprises an eighth branch connecting the first heat exchanger to the electric drive battery; and / or a ninth branch connecting the electric drive battery to the third heat exchanger.

[0024] Preferably, the at least one hydraulic circuit comprises a tenth branch connecting the first heat exchanger to the electric drive motor.

[0025] Preferably, the at least one hydraulic circuit further comprises an eleventh branch connecting the electric drive motor to the electric drive battery.

[0026] Preferably, the electric drive battery is capable of powering the electric drive motor.

[0027] Preferably, the at least one hydraulic circuit further comprises a twelfth branch connecting the electric drive motor to the sixth heat exchanger.

[0028] Preferably, the at least one hydraulic circuit comprises a thirteenth branch connecting the electric drive battery to the sixth heat exchanger.

[0029] Each characteristic introduced by the expression “preferably” given in relation to one of the aspects of the invention applies to all the other aspects of the invention.

[0030] The invention will be well understood and other aspects and advantages will appear clearly on reading the description which follows, given with reference to the figures appended and listed below.

[0031] [Fig.l] is a side view of a motor vehicle according to the invention.

[0032] [Fig.2] shows a diagram of a heat exchange system for a motor vehicle according to the invention.

[0033] In the following description, the term "comprise" is synonymous with "include" and is not limiting in that it allows the presence of other elements in the motor vehicle or the heat exchange system to which it relates. It is understood that the term "comprise" includes the terms "consist of". The terms "external" and "internal" will designate respectively that which is oriented towards the outside of the vehicle and towards the inside of the vehicle.

[0034] In the present description, the expression “thermally coupled” means that which allows a heat exchange during which a first fluid gives off calories while another fluid captures them.

[0035] The X axis represents the longitudinal direction, the Y axis represents the transverse direction, and the Z axis represents the vertical direction of the motor vehicle. These three axes define a direct trihedron.

[0036] In the present description, the technical characteristics are defined in the heat exchange system, unless explicitly mentioned otherwise.

[0037] Throughout the description, the different figures use the same reference signs to designate identical or similar entities.

[0038] [Fig.l] represents a motor vehicle 10, according to one embodiment of the invention.

[0039] The motor vehicle 10 comprises a structure 12. The structure 12 forms an outer body, or a main frame of the motor vehicle. The structure 12 forms a mounting support for various systems, including the drive system, the suspension systems, the steering system, the braking systems.

[0040] The structure 12 delimits different compartments of the motor vehicle 10, including the passenger compartment 14, the loading trunk, the engine compartment, also called the front compartment 16 in the sense that it is in front of the passenger compartment 14. The passenger compartment 14 is separated from the front compartment 16, in particular by a front apron 18 capable of blocking air circulation. The front apron 18 is a structural partition.

[0041] The propulsion system, also called a powertrain, comprises energy storage means and at least one motor, adapted to drive said motor vehicle 10. They respectively comprise an electric drive motor 20 and an electric drive battery 22. In the present illustration, the electric drive motor 20 is associated with the front wheels. According to an option or an alternative, an electric drive motor 20 is associated with the rear wheels. The electric drive battery 22 is arranged in the underbody, however it could be placed at any other location. The electric drive battery 22 is generally an electric energy accumulator.

[0042] The motor vehicle 10 further comprises a heat exchange system 24. The heat exchange system 24 is configured to regulate the temperature of the passenger compartment 14 and of various components such as the electric drive motor 20 and the electric drive battery 22. The heat exchange system 24 comprises a first heat exchanger 26, arranged on the front panel. It is also referred to as a radiator. The first heat exchanger 26 is, for example, a main exchanger or a front exchanger.

[0043] When the motor vehicle is moving, it is crossed by an incoming air flow coming from the environment. The heat exchange system 24 also comprises a module 28 for treating the air in the passenger compartment 14. The treatment module 28 is capable of cooling the air in the passenger compartment 14. It is optionally capable of drying it and / or heating it. The air in the passenger compartment 14 is renewed or recycled. It is blown by a fan (not shown).

[0044] The heat exchange between the first heat exchanger 26 and the processing module 28 is carried out through a closed loop 30. The closed loop 30 allows indirect heat exchange, it forms an intermediate heat transfer zone; which allows the use of different heat transfer fluids. The closed loop 30 is in the front compartment 16. The closed loop 30 is outside the passenger compartment 14. Thus, in the event of a leak of its heat transfer fluid, the latter does not spread into the passenger compartment 14, and dissipates into the environment via the front compartment 16. This aspect makes it possible to use heat transfer fluids to which the passengers must not be exposed. This contributes to health and safety, and opens the door to environmentally friendly fluids.

[0045] The motor vehicle 10 may for example be a private motor vehicle or a utility motor vehicle.

[0046] [Fig.2] shows a heat exchange system 24 of a motor vehicle, according to one embodiment of the invention. The motor vehicle may correspond to that presented in relation to [Fig.l].

[0047] The heat exchange system 24 comprises: at least one hydraulic circuit 32. The at least one hydraulic circuit 32 may be the same hydraulic circuit, or a plurality of hydraulic circuits interconnected via members. By hydraulic circuit, we mean a circuit which relates to the circulation of a liquid, such as water. It forms a network.

[0048] The heat exchange system 24 also comprises a closed loop 30. The closed loop 30 is fluidically isolated from the at least one hydraulic circuit 32. Thus, the heat exchange system 24 avoids mixing, contact between the fluids present. The closed loop 30 has at least one compressor 34 adapted to compress a first heat transfer fluid in said closed loop 30, and at least one expander 36.

[0049] The first heat transfer fluid is a compressible gas. It is a refrigerant. The first heat transfer fluid is flammable. It comprises difluoroethane and / or propane. Difluoroethane is also referred to as 1,1-Difluoroethane, or R-152a. It is commonly referred to by its acronym “DFE”.

[0050] The compressor 34 makes it possible to increase the pressure of the first heat transfer fluid in order to increase its temperature; and the expander 36 to lower the pressure; and therefore to reduce the temperature downstream in a direction of circulation corresponding to use in cooling. The first heat transfer fluid follows a thermodynamic cycle of compression then expansion in the closed loop 30, and possibly undergoes phase changes there. The closed loop 30 comprises a set of hydraulic pipes 38 connecting each of its members. The hydraulic pipes 38 form an auxiliary circuit. They connect said members in series.

[0051] The at least one hydraulic circuit 32 comprises a second heat transfer fluid which is different from the first heat transfer fluid. Preferably, the second heat transfer fluid comprises liquid. In operation, the second heat transfer fluid can combine its liquid phase and its gaseous phase. The second heat transfer fluid comprises a mixture of water and glycol.

[0052] The at least one hydraulic circuit 32 comprises a first heat exchanger 26 capable of ensuring a heat exchange between the second heat transfer fluid and the environment 40 of the motor vehicle. This heat exchange is carried out via the air flow entering the motor vehicle. The first heat exchanger 26 is an exchanger of the liquid air type. It is open to the environment 40.

[0053] The at least one hydraulic circuit 32 further comprises a second heat exchanger 42 capable of ensuring a heat exchange with the passenger compartment 14, via the second heat transfer fluid. The second heat exchanger 42 is integrated in the processing module 28. The second heat exchanger 42 is of the liquid-gas type.

[0054] The at least one hydraulic circuit 32 also comprises a third heat exchanger 44 and a fourth heat exchanger 46 which are thermally coupled to the closed loop 30. The third heat exchanger 44 and the fourth heat exchanger 46 each allow heat exchanges between the first heat transfer fluid and the second heat transfer fluid.

[0055] The at least one hydraulic circuit 32 comprises a first branch 48 connecting the first heat exchanger 26 to the third heat exchanger 44; and a second branch 50 connecting the fourth heat exchanger 46 to the second heat exchanger 42.

[0056] Thus, the transport of calories via the second heat transfer fluid is carried out indirectly. This makes it possible to use a first heat transfer fluid without the passengers being exposed to it. From then on, it becomes possible to carry a highly flammable gas such as propane or difluoroethane. Generally speaking, the first heat transfer fluid is a first flammable heat transfer fluid. The invention opens up the use of other fluids despite their constraints. It makes it possible to meet environmental constraints while respecting safety criteria.

[0057] The at least one hydraulic circuit 32 comprises a fifth heat exchanger 52 capable of ensuring a heat exchange with the passenger compartment 14, a third branch 54 connecting the third heat exchanger to the fifth heat exchanger 52. The fifth heat exchanger 52 is a liquid-air type exchanger.

[0058] The at least one hydraulic circuit 32 comprises a sixth heat exchanger 56 thermally coupled to the closed loop 30, and a fourth branch 58 connecting the sixth heat exchanger 56 to the first heat exchanger 26. The sixth heat exchanger 56 is a liquid-air type exchanger. The heat exchange system 24 comprises an electric heating module 60 of the sixth heat exchanger 56. The heating is carried out via a seventh branch 62. According to an alternative of the invention, the electric heating module is directly in the sixth heat exchanger. The fourth heat exchanger and the sixth heat exchanger are each associated with a dedicated expansion valve of the closed loop. The compressor is shared. According to an alternative of the invention, the fourth heat exchanger and the sixth heat exchanger are each associated with a dedicated compressor of the closed loop.

[0059] The presence of the electric heating module 60 makes it possible to supply calories to the sixth heat exchanger 56, and therefore to the closed loop 30. This allows operation in cold temperatures, between -20°C and -40°C. The operating range of the heat exchange system 24 is extended.

[0060] The at least one hydraulic circuit 32 comprises an eighth branch 64 connecting the first heat exchanger 26 to the electric drive battery 22; and a ninth branch 66 connecting the electric drive battery 22 to the third heat exchanger 44. Thus, the temperature of the electric drive battery 22 is controllable via the heat exchange system 24.

[0061] The at least one hydraulic circuit 32 comprises a tenth branch 68 connecting the first heat exchanger 26 to the electric drive motor 20; and an eleventh branch 70 connecting the electric drive motor 20 to the electric drive battery 22. By this means, the electric battery can be heated. A twelfth branch 72 connects the electric drive motor 20 to the sixth heat exchanger 56. A thirteenth branch 74 connects the electric drive battery 22 to the sixth heat exchanger 56. The electric drive motor 20 is generally a rotating electric machine. It is capable of electrically recharging the electric drive battery 22 by operating in mechanical energy recovery mode.

[0062] The third heat exchanger 44 is opposite the fourth heat exchanger 46 and the sixth heat exchanger 56 with respect to the compressor and the expansion valve. The fourth heat exchanger 46 and the sixth heat exchanger 56 are between the compressor 34 and the expansion valve 36. The closed loop 30 is preferably a cooling loop. It is configured, structurally and functionally, to cool the fourth heat exchanger 46 and the sixth heat exchanger 56 via the first heat transfer fluid.

[0063] The heat exchange system 24 comprises at least one drive pump (not shown) for the second heat transfer fluid through its different branches, and at least one valve authorizing or blocking the circulation of the second heat transfer fluid through said branches.

[0064] At least one or each branch comprises a forward pipe and a return pipe. They are parallel. Thus, each pair formed of a forward pipe and a return pipe forms a sub-circuit between two components.

[0065] According to one embodiment of the invention, each branch is provided with a drive pump.

[0066] According to one embodiment, the at least one hydraulic circuit is split between a passenger compartment part connected to the processing module 28, and a second part separated from the passenger compartment part by the third heat exchanger 44 and the sixth heat exchanger 56. The separations are carried out by the actuation of the valves and the pumps. Other separations of the at least one hydraulic circuit are provided. The heat exchange between these two parts of the at least one hydraulic circuit is carried out via the closed loop 30. The at least one hydraulic circuit can be split into three parts or more.

[0067] The heat exchange system 24 is adapted to operate according to several heat exchange modes, for example in heating or acclimatization of the passenger compartment 14.

[0068] The heat exchange system 24 is adapted to operate in heating demand mode of the electric drive battery 22 and / or the passenger compartment 14. The calories produced by the closed loop 30 are transferred to the second heat transfer fluid via the third heat exchanger 44; which operates as a condenser of the first heat transfer fluid. The recovered heat is selectively distributed to the electric drive battery 22 and / or to the passenger compartment 14, or to both.

[0069] The cooling of the first heat transfer fluid caused by the closed loop 30 is evacuated by the second heat transfer fluid in the sixth heat exchanger 56. This cooling phenomenon is also referred to as the production of “frigories”. The cooling of the second heat transfer fluid is distributed: either to the first heat exchanger 26 to recover the heat from the environment 40; or to the electric drive motor 20 to recover the calories produced during its operation; or to the electric heating module 60 when it is powered; or according to a combination of the three depending on the available energies.

[0070] The heat exchange system 24 is adapted to operate in cooling demand mode of the electric drive battery 22 and / or the passenger compartment 14.

[0071] The cooling of the first heat transfer fluid generated in the closed loop 30 is transferred to the second heat transfer fluid via the fourth heat exchanger 46 and the sixth heat exchanger 56. Once cooled, the proportion of the cold second heat transfer fluid is selectively distributed to the electric drive battery 22 or to the passenger compartment 14, or to both.

[0072] The calories produced by the closed loop 30 are evacuated via the third heat exchanger 44. The proportion of the second heat transfer fluid thus heated is sent to the first heat exchanger 26 in order to dissipate the heat into the environment 40.

[0073] The heat exchange system 24 is adapted to operate in cooling demand mode of the electric drive motor 20. The electric drive battery 22 and the passenger compartment 14 then do not need to be cooled. The heat produced by the electric drive motor 20 is directly transferred to the first heat exchanger 26 via the tenth branch 68 and the portion of second heat transfer fluid that it contains. From then on, the calories are dissipated into the environment 40.

[0074] The heat exchange system 24 is adapted to operate in cooling and heating demand mode for the passenger compartment 14. This allows in particular accelerated demisting of the windshield, thanks to drying by condensation then heating of the blown air.

[0075] The calories produced by the closed loop 30 are transferred to the second heat transfer fluid via the third heat exchanger 44. The second heat transfer fluid thus heated is distributed to the passenger compartment 14 via the fifth heat exchanger 52. The resulting cooling in the closed loop 30 is transferred to the second heat transfer fluid via the fourth heat exchanger 46. The quantity of cooled second heat transfer fluid which is produced is distributed to the passenger compartment 14 via the second heat exchanger 42.

[0076] Any surplus calories present in the second heat transfer fluid are evacuated by the second heat transfer fluid at the first heat exchanger 26. Any surplus cooled second heat transfer fluid is evacuated via the sixth heat exchanger 56, which itself dissipates the cooling in the first heat exchanger 26, to the electric drive motor 20, to the electric heating module 60, using the associated branches.

[0077] The invention allows an architecture with a single heat exchanger exposed to the environment. This aspect simplifies the heat exchange system 24, allows for varied operating modes, and respects a level of safety with a first heat transfer fluid itself having restrictions as to its use cases.

[0078] The invention comprises the combination of all the embodiments illustrated by all the figures.

Claims

Claims

1. Heat exchange system (24) for a motor vehicle (10) with a passenger compartment (14); the heat exchange system (24) comprising: at least one hydraulic circuit (32); a closed loop (30) cut off from the at least one hydraulic circuit (32) and having a compressor (34) adapted to compress a first heat transfer fluid in said closed loop (30), an expansion valve (36); the at least one hydraulic circuit (32) comprising a first heat exchanger (26) capable of ensuring a heat exchange with the environment (40) of the motor vehicle (10), a second heat exchanger (42) capable of ensuring a heat exchange with the passenger compartment (14), a third heat exchanger (44) thermally coupled to the closed loop (30), a first branch (48) connecting the first heat exchanger (26) to the third heat exchanger (44);characterized in that the at least one hydraulic circuit (32) further comprises a fourth heat exchanger (46) thermally coupled to the closed loop (30), and a second branch (50) connecting the fourth heat exchanger (46) to the second heat exchanger (42).;

2. Heat exchange system (24) according to claim 1, characterized in that the closed loop (30) comprises a first flammable heat transfer fluid; preferably, the first flammable heat transfer fluid comprises propane or difluoroethane.

3. Heat exchange system (24) according to one of claims 1 to 2, characterized in that the at least one hydraulic circuit (32) comprises a fifth heat exchanger (52) capable of ensuring a heat exchange with the passenger compartment (14), a third branch (54) connecting the third heat exchanger (44) to the fifth heat exchanger (52).

4. Heat exchange system (24) according to one of claims 1 to 3, characterized in that the at least one hydraulic circuit (32) comprises a sixth heat exchanger (56) thermally coupled to the closed loop (30), a fourth branch (58) connecting the sixth heat exchanger (56) to the first heat exchanger (26).

5. Heat exchange system (24) according to claim 4, characterized in that the heat exchange system (24) comprises an electric heating module (60) of the sixth heat exchanger (56); preferably, via a seventh branch (62).

6. Heat exchange system (24) according to one of claims 1 to 5, characterized in that the at least one hydraulic circuit (32) comprises a second heat transfer fluid which is different from the first heat transfer fluid; preferably, the second heat transfer fluid comprises a mixture of water and glycol.

7. Motor vehicle (10) comprising a heat exchange system (24), a passenger compartment (14), a front compartment; characterized in that the heat exchange system (24) is in accordance with one of claims 1 to 6; preferably, the motor vehicle (10) further comprises an electric drive motor (20) of the motor vehicle (10) and an electric drive battery (22), the closed loop (30) being in the front compartment.

8. Motor vehicle (10) according to claim 7, characterized in that the at least one hydraulic circuit (32) comprises an eighth branch (64) connecting the first heat exchanger (26) to the electric drive battery (22); and / or a ninth branch (66) connecting the electric drive battery (22) to the third heat exchanger (44).

9. Motor vehicle (10) according to one of claims 7 to 8, characterized in that the at least one hydraulic circuit (32) comprises a tenth branch (68) connecting the first heat exchanger (26) to the electric drive motor (20).

10. Motor vehicle (10) according to one of claims 7 to 9, characterized in that the at least one hydraulic circuit (32) further comprises an eleventh branch (70) connecting the electric drive motor (20) to the electric drive battery (22).

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