Thermal management system for a hybrid or electric vehicle

Abstract

The invention relates to a thermal management system of a hybrid or electric vehicle, which system comprises a reversible air-conditioning circuit (10) comprising a compressor (12), a first heat exchanger (14), a second heat exchanger (16), a first refrigerant storage device (18), a first expansion member (20) and a bi-fluid heat exchanger (22) arranged jointly on a circuit (11) of a heat-transfer fluid. The circuit (10) further comprises a first bypass branch (24) between a first bypass point (26) located on the main loop (LP) between the first heat exchanger (14) and the second heat exchanger (16) and a first junction point (28) located on the main loop (LP) between the first refrigerant storage device (18) and the first expansion member (20), the main loop (LP) further comprising a second refrigerant storage device (30) between the first heat exchanger (14) and the first bypass point (26). The circuit (11) of the third heat-transfer fluid comprises, in addition to the bi-fluid heat exchanger (22), a fourth heat exchanger (32).

Description

[0001] DESCRIPTION

[0002] TITLE: THERMAL MANAGEMENT SYSTEM FOR HYBRID OR ELECTRIC VEHICLE

[0003] Technical field of the invention

[0004] The invention relates to the field of motor vehicles and more particularly to a thermal management circuit for a hybrid or electric motor vehicle.

[0005] Technical background

[0006] In electric and hybrid vehicles, the thermal management of the passenger compartment is generally managed by a reversible air conditioning circuit. By reversible, we mean that this air conditioning circuit can operate in a cooling mode to cool the air going to the passenger compartment and in a heat pump mode to heat the air going to the passenger compartment. This reversible air conditioning circuit can also include a bypass to manage the temperature of the batteries of the electric or hybrid vehicle. It is thus possible to cool or even heat the batteries thanks to the reversible air conditioning loop. In heat pump mode, calories are taken from the outside air to be transmitted to an internal air flow which is blown into the passenger compartment to heat it.

[0007] It is known to use a refrigerant circuit successively comprising a compressor, an internal condenser, an expansion valve and an evaporator. The evaporator is for example used to cool the cabin air. In addition, the circuit can also typically include a bypass branch to an evapo-condenser on the front of the vehicle, which is used as a condenser in air conditioning mode and as an evaporator in heat pump mode. One of the aims of the present invention is therefore to improve the performance in air conditioning mode of such a system, while maintaining good performance in heat pump mode.

[0008] Summary of the invention

[0009] One aspect of the invention relates to a thermal management system for a hybrid or electric vehicle, the thermal management system comprising a reversible air conditioning circuit in which a refrigerant circulates, the reversible air conditioning circuit successively comprising, in a main refrigerant loop, a compressor, a first heat exchanger arranged to exchange calories with a first heat transfer fluid, for example directly or indirectly, the first heat transfer fluid being for example an internal air flow blown into the passenger compartment of the vehicle, a second heat exchanger arranged to exchange calories with a second heat transfer fluid, for example directly or indirectly, the second heat transfer fluid being for example an external air flow on the front of the vehicle, a first refrigerant storage device, in particular to provide a gas / liquid separation function,a first refrigerant fluid expansion member and a two-fluid heat exchanger arranged jointly on a circuit of a third heat transfer fluid, the third heat transfer fluid being for example a heat transfer liquid, the refrigerant fluid circuit further comprising a first bypass branch between a first bypass point located on the main loop between the first heat exchanger and the second heat exchanger, and a first junction point located on the main loop between the first refrigerant fluid storage device and the first expansion member, said main refrigerant fluid loop further comprising a second refrigerant fluid storage device between the first heat exchanger and said first bypass point, said third heat transfer fluid circuit comprising, in addition to said two-fluid heat exchanger, a fourth heat exchanger arranged to exchange calories,directly or indirectly, with a fourth heat transfer fluid, the fourth heat transfer fluid being, for example, an external air flow at the front of the vehicle.,

[0010] This system allows, thanks to the sub-cooling allowed by the first refrigerant storage device, to reduce the enthalpy of the fluid at the inlet of the evaporator and thus the performance of the system in air conditioning mode. This aspect of the invention is also an original and inexpensive way of implementing the heat pump mode, by using the two-fluid heat exchanger ("chiller") which is also used to cool the batteries in battery cooling mode, as a refrigerant evaporator, said third heat transfer fluid circulating in the two-fluid heat exchanger being passively cooled by the external heat exchanger (called the fourth heat exchanger).

[0011] According to certain aspects of the invention, the above system comprises one or more of the following characteristics taken in isolation or in all technically possible combinations:

[0012] - the first refrigerant storage device is integrated into the second heat exchanger, the second heat exchanger comprising a sub-cooling pass downstream of the first refrigerant storage device.

[0013] - the refrigerant circuit comprises a first three-way valve connecting the second refrigerant storage device, the second heat exchanger and the first bypass branch to the first junction point. - the two-fluid heat exchanger is connected to the compressor without the presence of another heat exchanger between the two-fluid heat exchanger and the compressor.

[0014] - the refrigerant circuit further comprises a second refrigerant bypass branch between a second bypass point and a second junction point, the second bypass point being located on the main loop between the second heat exchanger and the first expansion member, for example between the first junction point and the first expansion member, and the second junction point being located on the main loop between the two-fluid heat exchanger and the compressor.

[0015] - the second bypass branch comprises, in the direction of circulation of the refrigerant fluid, a second expansion member and a fifth heat exchanger arranged to exchange calories, directly or indirectly, with a fifth heat transfer fluid, in particular so that said fifth heat exchanger can operate as a refrigerant fluid evaporator when the system is in air conditioning mode and in dehumidification mode, the fifth heat transfer fluid being, for example, an internal air flow blown into the passenger compartment of the vehicle.

[0016] - the refrigerant circuit further comprises a third refrigerant bypass branch between a third bypass point and a third junction point, the third bypass point being located on the main loop between the first refrigerant storage device and the first junction point of the first bypass branch, and the third junction point being located on the second bypass branch between the fifth heat exchanger and the second junction point of the second bypass branch.

[0017] - the third branch branch comprises a stop valve. - the second branch branch comprises a first non-return valve located between the third junction point of the third branch branch and the second junction point of the second branch branch.

[0018] - the main loop comprises a second non-return valve located between the first refrigerant storage device and the first junction point of the first bypass branch.

[0019] - the second non-return valve is located between the third branch point of the third branch branch and the first junction point of the first branch branch.

[0020] - the system comprises an indoor air ventilation device in which said first heat exchanger is arranged.

[0021] - the third heat transfer fluid circuit comprises a first heat transfer fluid circulation branch, the first heat transfer fluid branch comprising a first pump and the two-fluid heat exchanger, the third heat transfer fluid circuit also comprising a so-called "external" branch for circulation of the third heat transfer fluid, said external branch comprising said fourth heat exchanger, an upstream end of said external branch being connected to a downstream end of said first branch and a downstream end of said external branch being connected to an upstream end of said first branch, in particular so as to together form a third heat transfer fluid circulation loop.

[0022] - said first branch also comprises an electric heating device, preferably upstream of the two-fluid heat exchanger, preferably directly upstream.

[0023] - the third heat transfer fluid circuit comprises a second circulation branch for the third heat transfer fluid, an upstream end of the second circulation branch being connected to a downstream end of said first branch, for example downstream of the two-fluid heat exchanger, and a downstream end of said second branch being connected to an upstream end of said first branch, in particular so as to together form a circulation loop for the third heat transfer fluid, said second branch preferably not comprising any device capable of significantly modifying the quantity of heat accumulated by the third heat transfer fluid.

[0024] -the third heat transfer fluid circuit comprises a third branch for circulating the third heat transfer fluid, said third branch comprising a second pump and a sixth heat exchanger, for example of the “electrical machines” type for exchanging heat with “electrical machines” of the vehicle.

[0025] - the third heat transfer fluid circuit comprises a fourth branch for circulation of the third heat transfer fluid, said fourth branch comprising a seventh heat exchanger, for example of the “battery” type for exchanging heat with “batteries” of the vehicle, an upstream end of said fourth branch being connected to a downstream end of said first branch and a downstream end of said fourth branch being connected to an upstream end of said first branch by a fifth branch for circulation of the third heat transfer fluid, in particular so as to form together a heat transfer fluid circulation loop, for example so as to allow the electric heating device to heat the third heat transfer fluid circulating in the seventh heat exchanger, or for example so as to allow, the two-fluid heat exchanger being active,to cool the third heat transfer fluid circulating in the seventh heat exchanger.,

[0026] - an upstream end of the fourth branch is connected to a downstream end of said third branch, and a downstream end of said fourth branch is connected to an upstream end of said third branch, in particular so as to form together a circulation loop for a third heat transfer fluid, for example so as to allow the third heat transfer fluid circulating in the seventh heat exchanger to be heated by recovering heat in the sixth heat exchanger.

[0027] - the third heat transfer fluid circuit comprises a sixth branch for circulation of the third heat transfer fluid, an upstream end of said sixth branch being connected to a downstream end of said third branch and a downstream end of said sixth branch being connected to an upstream end of said external branch, in particular so that said third branch, said sixth branch and said external branch together form a circulation loop for the third heat transfer fluid, in particular so as to allow the “passive” cooling of the third heat transfer fluid circulating in said sixth heat exchanger.

[0028] - the third heat transfer fluid circuit includes an expansion tank, for example located on said external branch.

[0029] - the third heat transfer fluid circuit comprises a second three-way valve connecting a downstream end of said first branch, an upstream end of said second branch and an upstream end of said external branch, configured to allow the circulation of the third heat transfer fluid between said first branch and said second branch or between said first branch and said external branch, the first branch being for example connected via a seventh branch.

[0030] - the third heat transfer fluid circuit comprises a third non-return valve on an eighth branch connecting an upstream end of said first branch and a downstream end of said fourth branch, downstream of a fourth branch point towards said seventh branch and upstream of a fourth branch point of junction of said third branch to said fourth branch.

[0031] - the third heat transfer fluid circuit comprises a third three-way valve connecting a downstream end of said fourth branch, an upstream end of said fifth branch and an upstream end of said third branch, configured to allow the circulation of the third heat transfer fluid between said fourth branch and said fifth branch or between said fourth branch and said third branch.

[0032] - the third heat transfer fluid circuit comprises a fourth three-way valve connecting a downstream end of said third branch, an upstream end of said fourth branch and an upstream end of said sixth branch to allow the circulation of the third heat transfer fluid between said third branch and said fourth branch or between said third branch and said sixth branch.

[0033] - said main loop comprises a third expansion member located between said first branch point of said first branch and said second heat exchanger, in particular so that said second heat exchanger can operate as a refrigerant fluid evaporator when the system is in heat pump mode, for example jointly or not with the dual-fluid heat exchanger also operating, for example, as a refrigerant fluid evaporator when the system is in heat pump mode.

[0034] - said third expansion member is integrated in a first three-way valve connecting the second refrigerant storage device, the second heat exchanger and the first bypass branch at the first junction point. Another aspect of the invention relates to a method of operating a system produced according to any one of the preceding claims, in which, in a first heat pump mode, said first heat exchanger operates as a refrigerant condenser or cooler, the two-fluid heat exchanger operating as a refrigerant evaporator.

[0035] According to certain aspects of the invention, the above method comprises one or more of the characteristics below taken in isolation or in all technically possible combinations:

[0036] - in a second heat pump mode, said first heat exchanger and said second heat exchanger operate as a refrigerant fluid condenser or cooler, the bifluid heat exchanger operating as a refrigerant fluid evaporator.

[0037] - in a first air conditioning mode, said first heat exchanger and said second heat exchanger operate as a refrigerant fluid condenser or cooler, the fifth heat exchanger operates as a refrigerant fluid evaporator.

[0038] - in a vehicle battery cooling mode, said first heat exchanger and said second heat exchanger operate as a refrigerant fluid condenser or cooler, the bifluid heat exchanger operating as a refrigerant fluid evaporator.

[0039] - in a mode of joint air conditioning and cooling of the vehicle batteries, said first heat exchanger (and said second heat exchanger) operate as a refrigerant fluid condenser or cooler, the bifluid heat exchanger and said fifth heat exchanger operating as a refrigerant fluid evaporator. - in a mode of dehumidification of the vehicle cabin, said first heat exchanger operates as a refrigerant fluid condenser or cooler, and said fifth heat exchanger operates as a refrigerant fluid evaporator.

[0040] - in a third heat pump mode, said first heat exchanger operates as a refrigerant condenser or cooler, said second heat exchanger operating as a refrigerant evaporator.

[0041] -in a fourth heat pump mode, said first heat exchanger operates as a refrigerant fluid condenser or cooler, said second heat exchanger and the two-fluid heat exchanger operating as a refrigerant fluid evaporator, said third heat transfer fluid circulating in said two-fluid heat exchanger being for example heated in said fourth heat exchanger.

[0042] Brief description of the figures

[0043] Other features and advantages of aspects of the invention will become apparent upon reading the following detailed description, provided by way of illustrative example, and for the understanding of which reference will be made to the appended drawings described briefly below.

[0044] Figure 1 is a schematic view which represents an example of an air conditioning circuit which equips the thermal management system produced according to one aspect of the invention.

[0045] Figure 2 is a view of an example of a heat transfer fluid circuit passing through the two-fluid heat exchanger of Figure 1.

[0046] Figure 3 is a schematic view showing the circuit of Figure 1 in a first heat pump mode.

[0047] Figure 4 is a schematic view showing the circuit of Figure 1 in a battery cooling mode. Figure 5 is a schematic view showing the circuit of Figure 1 in a joint dehumidification and heat pump mode.

[0048] Figure 6 is a schematic view which represents an example of an air conditioning circuit which equips the thermal management system produced according to another aspect of the invention.

[0049] Figure 7 is a schematic view showing the circuit of Figure 6 in a heat pump mode.

[0050] Figure 8 is a schematic view showing the circuit of Figure 6 in another heat pump mode.

[0051] Figure 9 is a schematic view showing the circuit of Figure 6 in a combined heat pump and dehumidification mode.

[0052] Detailed description of the invention

[0053] In the remainder of the description, elements having an identical structure or similar functions will be designated by the same reference.

[0054] In the following description, the term "a first element upstream of a second element" means that the first element is placed before the second element relative to the direction of circulation, or path, of a fluid. Similarly, the term "a first element downstream of a second element" means that the first element is placed after the second element relative to the direction of circulation, or path, of the fluid in question. The direction of circulation is defined by the arrows of the compressor or by the arrows of the pumps where applicable.

[0055] The term "branch" here refers to a section of circuit open at both ends comprising only elements arranged in series.

[0056] It should also be noted that the term "batteries" should not be understood as all the batteries in the vehicle, but as several batteries. The term "battery" should be understood as any energy storage unit capable of restoring this energy in electrical form.

[0057] In the drawings, the pipes in which the refrigerant fluid is moving will be shown in bold lines and the pipes in which the heat transfer fluid is not moving will be shown in thin lines.

[0058] Note that the terms "first", "second", "third" are simple names that do not imply a specific number of components. Thus, we can refer to a "fifth" heat exchanger without there being five or more heat exchangers in the circuit, the circuit may, for example, have fewer than five.

[0059] As illustrated in the various figures, the invention relates to a thermal conditioning system. This is, for example, a thermal management system for a motor vehicle. This concerns an electric or hybrid motor vehicle which comprises an electric motor which provides engine torque to the drive wheels of the vehicle. The electric motor is supplied with electric current at least by batteries, called traction batteries. During operation of the vehicle, the electric motor and the battery are likely to produce heat.

[0060] As more particularly illustrated in Figure 1, said system comprises a first air conditioning circuit 10 in which a refrigerant fluid (or “refrigerant fluid circuit”) circulates, as shown in Figure 1, and a second heat transfer fluid circuit 11 in which a heat transfer fluid circulates, as shown in Figure 2.

[0061] The heat transfer fluid is, for example, a heat transfer liquid such as water comprising an antifreeze, in particular glycolated water, or any other suitable heat transfer fluid. The refrigerant is, for example, a hydrofluorocarbon, such as R-134a or R1234yf or R744. As shown in Figure 1, the circuit 10 is a reversible air conditioning circuit in which a refrigerant circulates.

[0062] The refrigerant circuit 10 successively comprises, in the direction of circulation of the refrigerant, in a main loop LP of refrigerant, a compressor 12, a first heat exchanger 14 arranged to exchange calories with a first heat transfer fluid, a second heat exchanger 16 arranged to exchange calories with a second heat transfer fluid, a first storage device 18 of refrigerant, in particular to ensure a gas / liquid separation function, a first expansion member 20 of the refrigerant and a two-fluid heat exchanger 22 arranged jointly on a circuit 11 of a third heat transfer fluid.

[0063] The first refrigerant storage device 18 is commonly referred to as a “bottle”. It may include a refrigerant desiccant. It provides a gas / liquid separation function so that the outgoing fluid is liquid.

[0064] The first expansion member 20 is typically an electronic fluid expansion valve or “electronic expansion valve”.

[0065] The two-fluid heat exchanger 22 is here connected directly to the compressor 12, i.e. without the presence of another heat exchanger between the two-fluid heat exchanger 22 and the compressor 12.

[0066] The two-fluid heat exchanger 22 is configured to allow heat exchange between the refrigerant fluid, circulating in the air conditioning circuit 10, and the third heat transfer fluid, circulating in the circuit 11 of the third heat transfer fluid, without mixing between the heat transfer fluid and the refrigerant fluid. This type of heat exchanger is commonly called a "chiller" by those skilled in the art, in the example of FIG. 1. It is more generally a liquid / liquid type heat exchanger capable of exchanging calories between two separate liquids. The first heat exchanger 14 arranged to exchange calories with a first heat transfer fluid is here an internal condenser of a ventilation device 56 for interior air in the passenger compartment of the vehicle. Thus, said first heat transfer fluid is in this example an internal air flow Fi blown into the passenger compartment of the vehicle.

[0067] The first heat exchanger 14 is more generally a heat exchanger operating as a condenser or cooler of the refrigerant fluid.

[0068] The second heat exchanger 16 arranged to exchange calories with the second heat transfer fluid is here a condenser on the front of the vehicle. The second heat transfer fluid is therefore in this example an external air flow Fe on the front of the vehicle. More generally, the second heat exchanger 16 is a heat exchanger arranged to act as a condenser or cooler of the refrigerant fluid.

[0069] The first refrigerant storage device 18 is here integrated into the second heat exchanger 16, which comprises a downstream refrigerant sub-cooling pass.

[0070] The refrigerant circuit 10 further comprises a first bypass branch 24 between a first bypass point 26 located on the main loop LP between the first heat exchanger 14 and the second heat exchanger 16 and a first junction point 28 located on the main loop LP between the first refrigerant storage device 18 and the first expansion member 20.

[0071] The first bypass branch 24 makes it possible to short-circuit the second heat exchanger 16 and thus bring the refrigerant fluid to the two-fluid heat exchanger 22 as will be explained in more detail further below with reference to FIG. 3.

[0072] Said main refrigerant loop LP also comprises a second refrigerant storage device 30 between the first heat exchanger 14 and said first branch point 26.

[0073] The second refrigerant storage device 30 is commonly referred to as a “bottle”. It may include a refrigerant desiccant. It provides a gas / liquid separation function so that the outgoing fluid is liquid.

[0074] The third heat transfer fluid circuit 11 comprises, in addition to said two-fluid heat exchanger 22, a fourth heat exchanger 32 arranged to exchange calories, directly or indirectly, with a fourth heat transfer fluid.

[0075] The fourth heat exchanger 32 is here a radiator (“external”) on the front of the vehicle, the fourth heat transfer fluid being in this example an external air flow (Fe) on the front of the vehicle. It is more generally a heat exchanger for cooling or heating the third heat transfer fluid, i.e. for cooling or heating the heat transfer liquid circulating in the fourth heat exchanger 32.

[0076] The third heat transfer fluid is here, for example, glycolated water or another heat transfer fluid of any suitable type.

[0077] The refrigerant circuit 10 further comprises a second refrigerant bypass branch 34 between a second bypass point 36 and a second junction point 38, the second bypass point 34 being located on the main loop LP between the second heat exchanger 26 and the first expansion member 20, for example between the first junction point 26 and the first expansion member 20, and the second junction point 38 being located on the main loop LP between the two-fluid heat exchanger 22 and the compressor 12.

[0078] The first branch branch 24 comprises, in the direction of circulation of the refrigerant fluid, a second expansion member 40 and a fifth heat exchanger 42 arranged to exchange calories, directly or indirectly, with a fifth heat transfer fluid, in particular so that said fifth heat exchanger 42 can operate as a refrigerant fluid evaporator when the system is in air conditioning mode and in dehumidification mode, the fifth heat transfer fluid being in this example an internal air flow (Fi) blown into the passenger compartment of the vehicle. Indeed, the fifth heat exchanger 42 is typically an evaporator integrated into the interior air ventilation device 56. It is more generally a heat exchanger for evaporating the refrigerant fluid circulating within it.

[0079] The second expansion member 40 is typically an electronic expansion valve, or electronic “expansion valve”.

[0080] The refrigerant circuit 10 further comprises a third refrigerant bypass branch 44 between a third bypass point 46 and a third junction point 48, the third bypass point 46 being located on the main loop LP between the first refrigerant storage device 18 and the first junction point 28 of the first bypass branch 24, and the third junction point 48 being located on the second bypass branch 34 between the fifth heat exchanger 42 and the second junction point 38 of the second bypass branch 34.

[0081] The refrigerant circuit 10 is also equipped with different types of valves or flaps.

[0082] The refrigerant circuit 10 comprises a first three-way valve 33 connecting the second refrigerant storage device 30, the second heat exchanger 16 and the first bypass branch 24 to the first junction point 26. This first three-way valve 33 makes it possible to circulate the refrigerant from the first heat exchanger 14 to the second heat exchanger 16 or to the first bypass branch 24. Alternatively, these are two stop valves respectively on one and the other of the branches downstream of the first bypass point 26. The third bypass branch 44 comprises a stop valve 50, but does not comprise, in this example, a heat exchanger.

[0083] The second bypass branch 34 comprises a first non-return valve 52 located between the first junction point of the second bypass branch 34 and the third junction point 48 of the third bypass branch 44.

[0084] The main loop LP comprises a second non-return valve 54 located between the first refrigerant storage device 18 and the first junction point 28 of the first bypass branch 24, more precisely between the third bypass point 46 of the third bypass branch 44 and the first junction point 28 of the first bypass branch 24.

[0085] The main circuit operation modes of Figure 1 will be explained in more detail with reference to Figures 3 to 5.

[0086] Figure 2 illustrates by way of example a possible heat transfer fluid circuit for said third heat transfer fluid passing through said two-fluid heat exchanger 22.

[0087] The third heat transfer fluid circuit 11 comprises a first branch B1 for circulating the heat transfer fluid comprising a first pump 58 and the two-fluid heat exchanger 22. The third heat transfer fluid circuit 11 also comprises a so-called “external” branch BE for circulating the third heat transfer fluid, said external branch BE comprising said fourth heat exchanger (32).

[0088] In order to form a circulation loop of the third heat transfer fluid, an upstream end of said external branch BE is connected to a downstream end of said first branch B1 and a downstream end of said external branch being connected to an upstream end of said first branch B1. In this way, when the first pump 58 is active, the heat transfer liquid circulates through the two-fluid heat exchanger 22 and through the fifth heat exchanger 32, which allows passive heating of the heat transfer liquid and thus passive heating of the refrigerant passing through the two-fluid heat exchanger.

[0089] The third heat transfer fluid circuit 11 also comprises a second branch B2 for circulating the third heat transfer fluid, an upstream end of the second circulation branch B2 being connected to a downstream end of said first branch B1, for example downstream of the two-fluid heat exchanger 22, and a downstream end of said second branch B2 being connected to an upstream end of said first branch B1, so as to together form a third heat transfer fluid circulation loop.

[0090] Said second branch B2 preferably does not include any device capable of significantly modifying the quantity of heat accumulated by the first heat transfer fluid.

[0091] This arrangement of the first and second branches B1, B2 allows the circulation of the third heat transfer fluid in a loop in the first pump 58, the electric heating device 60 and in the bifluid heat exchanger 22, which allows this active heating of the refrigerant fluid when the electric heating device 60 is active. Preferably the electric heating device 60 is directly upstream of the bifluid heat exchanger 22. This mode of heating the refrigerant fluid is useful for example when the outside temperature is too cold to heat the refrigerant fluid. This minimum temperature will depend on the type of refrigerant used.

[0092] The third heat transfer fluid circuit 11 comprises a third branch B3 and a fourth branch B4 for circulating the third heat transfer fluid.

[0093] The third branch B3 comprises a second pump 62 and a sixth heat exchanger 66, for example of the “electrical machine” type for exchanging heat with electrical machines of the vehicle.

[0094] The fourth branch B4 comprises a seventh heat exchanger 68, for example of the “battery” type for exchanging heat with batteries of the vehicle, an upstream end of said fourth branch B4 being connected to a downstream end of said first branch B1 and a downstream end of said fourth branch B4 being connected to an upstream end of said first branch B1 by a fifth branch B5 for circulating the third heat transfer fluid, in particular so as to form together a heat transfer fluid circulation loop, for example so as to allow the electric heating device 60 to heat the third heat transfer fluid circulating in the seventh heat exchanger 68, or for example so as to allow, the two-fluid heat exchanger 22 being active, to cool the third heat transfer fluid circulating in the seventh heat exchanger 68 and thus cool the batteries of the vehicle.

[0095] An upstream end of the fourth branch B4 is here connected to a downstream end of said third branch B3, and a downstream end of said fourth branch B4 is connected to an upstream end of said third branch B3, so as to form together a circulation loop of third heat transfer fluid, for example so as to allow the third heat transfer fluid circulating in the seventh heat exchanger 68 to be heated by recovering heat in the sixth heat exchanger 66, i.e. in the electrical machines of the vehicle (electric motor or power electronics for example).

[0096] The third heat transfer fluid circuit 11 also comprises a sixth branch B6 for circulation of the third heat transfer fluid, an upstream end of said sixth branch being connected to a downstream end of said third branch B3 and a downstream end of said sixth branch B6 being connected to an upstream end of said external branch BE, in particular so that said third branch B3, said sixth branch B6 and said external branch BE together form a circulation loop for the third heat transfer fluid, in particular so as to allow the “passive” cooling of the third heat transfer fluid circulating in said sixth heat exchanger (66).

[0097] Furthermore, the heat transfer fluid circuit 11 here comprises different valves or flaps so as to direct the circulation of the heat transfer fluid.

[0098] The third heat transfer fluid circuit 11 comprises a “second” three-way valve 74, a “third” three-way valve 76 and a “fourth” three-way valve 78.

[0099] Said second three-way valve 74 connects a downstream end of said first branch B1, an upstream end of said second branch B2 and an upstream end of said external branch BE, configured to allow the circulation of the third heat transfer fluid between said first branch B1 and said second branch B2 or between said first branch B1 and said external branch BE, the first branch B1 being for example connected via a seventh branch B7.

[0100] The third three-way valve 76 connects a downstream end of said fourth branch B4, an upstream end of said fifth branch B5 and an upstream end of said third branch B3, configured to allow the circulation of the third heat transfer fluid between said fourth branch B4 and said fifth branch B5 or between said fourth branch B4 and said third branch B3.

[0101] The fourth three-way valve 78 connects a downstream end of said third branch B3, an upstream end of said fourth branch B4 and an upstream end of said sixth branch B6 to allow the circulation of the third heat transfer fluid between said third branch B3 and said fourth branch B4 or between said third branch B3 and said sixth branch B6.

[0102] Furthermore, a “third” non-return valve 80 is arranged on an eighth branch B8 connecting an upstream end of said first branch B1 and a downstream end of said fourth branch B4, downstream of a fourth branch point 82 to said seventh branch B7 and upstream of a fourth junction point 84 of said third branch B3 to said fourth branch B4. This non-return valve 80 allows for example the circulation in a loop in the second pump 62, the sixth heat exchanger 66 and the seventh heat exchanger 68, while also allowing the circulation of heat transfer fluid from the first branch B1 to the fourth branch B4.

[0103] The circulation of heat transfer fluid from the first branch B1 to the seventh branch B7 is here obtained by closing the downstream end of the fourth branch B4 at the level of said third three-way valve 76.

[0104] It should also be noted that the third heat transfer fluid circuit 11 comprises an expansion tank 72, located on said external branch BE. Alternatively, the expansion tank is located elsewhere in the third heat transfer fluid circuit 11.

[0105] Different operating modes of the reversible air conditioning circuit are illustrated with reference to Figures 3 to 5.

[0106] In Figure 3, the refrigerant circuit 10 operates in a first heat pump mode.

[0107] The first three-way valve 33 closes the circulation to said second heat exchanger 16 and ensures the circulation from the first heat exchanger 14 to the first bypass branch 24. The second expansion member 40 is closed, preventing circulation to said fifth heat exchanger 42. The first expansion member 20 is, however, partially open, so as to subject the refrigerant fluid to expansion before arriving in said two-fluid heat exchanger 22. The refrigerant fluid is then conducted to the compressor 12 due to the non-return valve 52. The stop valve 50 is opened if necessary to bring the load from the condenser to the active loop.

[0108] The refrigerant circuit 10 thus forms a closed loop of refrigerant circulating successively in the compressor 12, in the first heat exchanger 14 operating as a refrigerant condenser or cooler, in the second storage device 30 of the bottle type, in the first expansion member 20, and in the two-fluid heat exchanger 22 operating as a refrigerant evaporator, thus heating the refrigerant. To bring this necessary heat to the refrigerant, the third heat transfer fluid is, for example, set in motion towards the external radiator 32 to capture calories in the external air flow Fe, as previously explained above with reference to FIG. 2.

[0109] To summarize, this first heat pump mode uses the chiller 22 (“bidluide heat exchanger”) for cooling the batteries as an evaporator.

[0110] In a battery cooling mode illustrated in FIG. 4, the first three-way valve 33 closes the circulation to the first bypass branch 24 and ensures the circulation from the first heat exchanger 14 to said second heat exchanger 16. The stop valve 50 is closed. The second expansion member 40 is closed and the first expansion member 20 is partially open to achieve expansion of the refrigerant fluid.

[0111] The refrigerant circuit 10 thus forms an active loop of refrigerant circulating successively through the compressor 12, the first heat exchanger 14 operating as a refrigerant condenser or cooler, in the second bottle-type storage device 30, in the second heat exchanger 16 operating as a refrigerant condenser or cooler, in the first expansion member 20, and in the two-fluid heat exchanger 22 operating as a refrigerant evaporator, thus heating the refrigerant. The refrigerant thus cools the third heat transfer fluid, which makes it possible to cool the batteries by circulating the third heat transfer fluid in the seventh “battery” heat exchanger 68.The removal of heat from the batteries jointly in the first heat exchanger 1' and in the second heat exchanger 16 makes it possible to maximize the cooling power of the batteries.

[0112] In a mode of operation not shown, which differs from the mode of FIG. 2 in that the first expansion member 20 is closed and the second expansion member 40 partially open so as to evaporate the refrigerant fluid in the fifth heat exchanger 42, a mode of air conditioning of the passenger compartment is obtained with significant refrigeration power.

[0113] In another operating mode not shown, which differs from the mode of FIG. 2 by the fact that both the first expansion member 20 and the second expansion member 40 are partially open so as to evaporate the refrigerant fluid in the two-fluid heat exchanger 22 and in the fifth heat exchanger 42, a combined mode of cooling the batteries and air conditioning the passenger compartment is obtained.

[0114] Figure 5 illustrates a combined dehumidification and heat pump mode.

[0115] The first three-way valve closes the circulation to the first bypass branch 24 and ensures the circulation from the first heat exchanger 14 to the second heat exchanger 16. The first expansion member 20 and the second expansion member 40 are partially open so as to expand the refrigerant fluid and so that the two-fluid heat exchanger 22 and said fifth heat exchanger 42 operate as a refrigerant fluid evaporator. The stop valve 50 is opened if necessary to bring charge from the condenser to the active loop.

[0116] The first heat exchanger 14 and the second heat exchanger 16 both operate as a refrigerant condenser (or cooler). As in the operating mode of FIG. 3, the two-fluid heat exchanger captures heat from the refrigerant, which heat is returned to the first heat exchanger 14 to heat the passenger compartment of the vehicle. Furthermore, the fifth heat exchanger 42 makes it possible to dehumidify the air by lowering the temperature of the internal air passing through it and by condensing a portion of the humidity present in this internal air.

[0117] Another dehumidification mode not shown simply differs from the mode of FIG. 5 in that the first expansion member 20 is closed, which prevents the circulation of refrigerant fluid in the two-fluid heat exchanger 22 (or “chiller”).

[0118] Figure 6 illustrates a second embodiment of a refrigerant circuit according to another aspect of the invention, which simply differs from the circuit of Figure 1 in that it comprises a third expansion member 70 located between said first branch point 26 of said first branch branch 24 and said second heat exchanger 16.

[0119] In this example, said third expansion member 70 is integrated into the first three-way valve (33). Alternatively, the third expansion member 70 is independent of the first three-way valve 26.

[0120] The third expansion member 70 is of any suitable type. It is, for example, a device of an electronic fluid expansion valve or “electronic expansion valve”.

[0121] The third expansion member 70 makes it possible to subject the refrigerant fluid arriving in the second heat exchanger 16 to an expansion and thus to operate the second heat exchanger as a refrigerant fluid evaporator while circulating in the same direction in said second heat exchanger, compared to the direction of circulation in which the second heat exchanger 16 is used as a refrigerant fluid condenser (or cooler). so that said second heat exchanger 16 can operate as a refrigerant fluid evaporator when the system is in heat pump mode, for example jointly or not with the bifluid heat exchanger (22) also operating, for example, as a refrigerant fluid evaporator when the system is in heat pump mode.

[0122] The circuit of Figure 6 enables the illustrated modes of operation described with reference to Figures 3 to 5 and also enables other modes of operation which are described with reference to Figures 7 to 9.

[0123] In Figure 7, the first three-way valve 33 closes the first bypass branch 24 and allows the circulation of refrigerant from the first heat exchanger to the second heat exchanger 16. The third expansion member 70 is partially open. The first expansion member 20 and the second expansion member 40 are closed. The stop valve 50 is open. The refrigerant circuit thus ensures circulation of refrigerant in a loop of the compressor 12, to the first heat exchanger 141e second heat exchanger 16, then again to the compressor. The first heat exchanger 16 operates as a refrigerant condenser (or cooler) while the second heat exchanger 16 operates as a refrigerant evaporator. This is therefore an alternative heat pump mode to the heat pump mode in which the two-fluid heat exchanger 22 is used as an evaporator.

[0124] Figure 8 illustrates another heat pump mode corresponding to the combination of the operating modes of Figures 3 and 7. The refrigerant circuit 10 of Figure 8 compared to Figure 7 is that said first expansion member 20 is partially open so as to allow the circulation of refrigerant fluid to the bifluid heat exchanger 22 while subjecting the refrigerant fluid water to expansion in said first expansion member 20 and in that the stop valve 50 is closed.

[0125] The refrigerant circuit 10 thus forms a refrigerant circulation loop from the compressor 12 to the first heat exchanger 14 then to the second heat exchanger 16 before circulating to the two-fluid heat exchanger 22.

[0126] The first heat exchanger 1' operates as a condenser (or refrigerant cooler), while the second heat exchanger 14 and the bifluid heat exchanger 22 operate as an evaporator.

[0127] More particularly, the second heat exchanger 16 operates as an evaporator on the outside air Fe and the two-fluid heat exchanger 22 operates as an evaporator on the third heat transfer fluid, which, as explained with reference to FIG. 2, is heated passively by circulating in the external radiator 32 (or fourth heat exchanger) or actively by circulating in the electric heating device 60.

[0128] The embodiment of figure 8 allows for increased heating power in heat pump mode.

[0129] Finally, Figure 9 illustrates an operating mode combining the increased power heat pump mode of Figure 8 with a dehumidification mode. The refrigerant circuit 10 differs from Figure 8 in that the second expansion member 40 is partially open, so as to allow the circulation of refrigerant to the fifth heat exchanger 42 while subjecting the refrigerant to water expansion in said second expansion member. In this way, a portion of the refrigerant coming from the second exchanger 16 branches off to the first expansion member 20 and the dual-fluid heat exchanger 22 and another portion of the refrigerant arriving at the second branch point 36 flows to the second expansion member 40 then to the fifth heat exchanger 42 before returning to the compressor 12.The fifth heat exchanger 42 thus operates as a refrigerant evaporator in parallel with the dual-fluid heat exchanger 22, which also operates as a refrigerant evaporator 22. The indoor air ventilation device 16 thus dehumidifies the internal air fluid which is first cooled in the fifth heat exchanger 42 before being reheated in said first heat exchanger 16.

Claims

CLAIMS 1. Thermal management system of a hybrid or electric vehicle, the thermal management system comprising a reversible air conditioning circuit (10) in which a refrigerant circulates, the reversible air conditioning circuit (10) comprising, in the direction of circulation of the refrigerant, in a main loop (LP) of refrigerant, a compressor (12), a first heat exchanger (14) arranged to exchange calories with a first heat transfer fluid, for example directly or indirectly, the first heat transfer fluid being for example an internal air flow (Fi) blown into the passenger compartment of the vehicle, a second heat exchanger (16) arranged to exchange calories with a second heat transfer fluid, for example directly or indirectly, the second heat transfer fluid being for example an external air flow (Fe) on the front of the vehicle,in particular so that said second heat exchanger (16) can operate as a cooler or condenser of refrigerant fluid when the system is in air conditioning mode, a first storage device (18) of refrigerant fluid, in particular to ensure a gas / liquid separation function, a first expansion member (20) of the refrigerant fluid and a two-fluid heat exchanger (22) arranged jointly on a circuit (11) of a third heat transfer fluid, the third heat transfer fluid being for example a heat transfer liquid,the refrigerant circuit (10) further comprising a first bypass branch (24) between a first bypass point (26) located on the main loop (LP) between the first heat exchanger (14) and the second heat exchanger (16) and a first junction point (28) located on the main loop (LP) between the first refrigerant storage device (18) and the first expansion member (20), in particular so that said two-fluid heat exchanger (22) can, operate as a refrigerant fluid evaporator when the system is in heat pump mode, said main refrigerant fluid loop (LP) further comprising a second refrigerant fluid storage device (30) between the first heat exchanger (14) and said first branch point (26), said third heat transfer fluid circuit (11) comprising, in addition to said two-fluid heat exchanger (22), a fourth heat exchanger (32) arranged to exchange calories, directly or indirectly, with a fourth heat transfer fluid, the fourth heat transfer fluid being, for example, an external air flow (Fe) at the front of the vehicle.

2. System according to the preceding claim, in which the first refrigerant storage device (18) is integrated into the second heat exchanger (16), the second heat exchanger (16) comprising a sub-cooling pass downstream of the first refrigerant storage device (18).

3. System according to claim 1 or 2, in which the refrigerant circuit (10) further comprises a second refrigerant bypass branch (34) between a second bypass point (36) and a second junction point (38), the second bypass point (36) being located on the main loop (LP) between the second heat exchanger (16) and the first expansion member (20), for example between the first junction point (28) and the first expansion member (20), and the second junction point (38) being located on the main loop (LP) between the two-fluid heat exchanger (22) and the compressor (12).

4. System according to the preceding claim, in which the second bypass branch (34) comprises, in the direction of circulation of the refrigerant fluid, a second expansion member (40) and a fifth heat exchanger (42) arranged to exchange calories, directly or indirectly, with a fifth heat transfer fluid, in particular so that said fifth heat exchanger (42) can operate as a refrigerant fluid evaporator when the system is in air conditioning mode and in dehumidification mode, the fifth heat transfer fluid being for example an internal air flow (Fi) blown into the passenger compartment of the vehicle.

5. System according to claim 3 or 4, wherein the refrigerant circuit (10) further comprises a third refrigerant bypass branch (44) between a third bypass point (46) and a third junction point (48), the third bypass point (46) being located on the main loop (LP) between the first refrigerant storage device (18) and the first junction point (28) of the first bypass branch (24), and the third junction point (48) being located on the second bypass branch (34) between the fifth heat exchanger (42) and the second junction point (38) of the second bypass branch (34).

6. System according to any one of the preceding claims, in which the circuit (1 1 ) of third heat transfer fluid comprises a first branch (B1 ) for circulation of heat transfer fluid, the first branch (B1 ) of heat transfer fluid comprising a first pump (58) and the two-fluid heat exchanger (22), the circuit (1 1 ) of third heat transfer fluid also comprising a so-called "external" branch (BE) for circulation of the third heat transfer fluid, said external branch (BE) comprising said fourth heat exchanger (32), an upstream end of said external branch (BE) being connected to a downstream end of said first branch (B1 ) and a downstream end of said external branch (BE) being connected to an upstream end of said first branch (B1 ), in particular so as to form together a third heat transfer fluid circulation loop.

7. System according to the preceding claim, in which said first branch (B1) also comprises an electric heating device (60), preferably upstream of the two-fluid heat exchanger (22), preferably directly upstream.

8. System according to claim 6 or 7, in which the circuit (11) of third heat transfer fluid comprises a second branch (B2) for circulation of the third heat transfer fluid, an upstream end of the second circulation branch (B2) being connected to a downstream end of said first branch (B1), for example downstream of the two-fluid heat exchanger (22), and a downstream end of said second branch (B2) being connected to an upstream end of said first branch (B1), in particular so as to form together a circulation loop of third heat transfer fluid, said second branch (B2) preferably not comprising any device capable of substantially modifying the quantity of heat accumulated by the third heat transfer fluid.

9. System according to any one of the preceding claims, in which said main loop (LP) comprises a third expansion member (70) located between said first bypass point (34) of said first bypass branch (24) and said second heat exchanger (16), in particular so that said second heat exchanger (16) can operate as a refrigerant fluid evaporator when the system is in heat pump mode, for example jointly or not with the bifluid heat exchanger (22) also operating, for example, as a refrigerant fluid evaporator when the system is in heat pump mode.

10. Method of operating a system according to any one of the preceding claims, wherein, in a first heat pump mode, said first heat exchanger (14) operates as a refrigerant condenser or cooler, the bifluid heat exchanger (22) operating as a refrigerant evaporator. 1 1. Method according to the preceding claim in which the system is according to any one of the preceding claims taken together with claim 4, and in which, in a first air conditioning mode, said first heat exchanger (14) and said second heat exchanger (16) operate as a refrigerant fluid condenser or cooler, the fifth heat exchanger (42) operates as a refrigerant fluid evaporator.

12. Method according to claim 10 or 11, wherein, in a battery cooling mode of the vehicle, said first heat exchanger (14) and said second heat exchanger (16) operate as a refrigerant condenser or cooler, the bifluid heat exchanger (22) operating as a refrigerant evaporator.

13. Method according to any one of claims 10 to 12, in which the system is according to any one of the preceding claims taken together with claim 9, in a second heat pump mode, said first heat exchanger (14) operates as a refrigerant condenser or cooler, said second heat exchanger (16) operating as a refrigerant evaporator.

14. Method according to the preceding claim, in which, in a third heat pump mode, said first heat exchanger (14) operates as a refrigerant fluid condenser or cooler, said second heat exchanger (16) and the two-fluid heat exchanger (22) operating as a refrigerant fluid evaporator, said third heat transfer fluid circulating in said two-fluid heat exchanger (22) being for example heated in said fourth heat exchanger (32).

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