Heat transfer fluid circuit for a thermal treatment system of a vehicle

Abstract

The present invention relates to a heat transfer fluid circuit (2) comprising: - a first loop (4) comprising a first heat exchanger (6), and a second heat exchanger (7), a third heat exchanger (8), and a fourth heat exchanger (9); - a second loop (11) comprising a fifth heat exchanger (13) and a sixth heat exchanger (14), characterised in that the heat transfer fluid circuit (2) comprises a first branch (16) extending between a first junction point (18) and a first convergence point (19), a second branch (17) extending between a first divergence point (20) and a second convergence point (21), and a third branch (22) extending between the first junction point (18) and a third convergence point (23).

Description

[0001] DESCRIPTION

[0002] Title of the invention: Heat transfer fluid circuit for a vehicle heat treatment system

[0003] The present invention relates to the field of heat treatment systems for a motor vehicle, and more particularly concerns a heat transfer fluid circuit integrated into such heat treatment systems.

[0004] Motor vehicles are commonly equipped with a refrigerant circuit and at least one heat transfer fluid circuit, both used to participate in a heat treatment of different areas or different components of the vehicle. It is particularly known to use the refrigerant circuit and / or the heat transfer fluid circuit to heat treat an air flow sent into the passenger compartment of the vehicle equipped with such a circuit. This heat treatment is carried out in particular by means of a circulation of the refrigerant within a ventilation, heating and / or air conditioning system arranged in the vehicle.

[0005] In another application of this circuit, it is known to use the heat transfer fluid circuit to cool components of the vehicle's powertrain, such as for example an electrical storage device, the latter being used to supply energy to an electric motor capable of setting the vehicle in motion. The heat treatment system thus supplies the energy capable of cooling the electrical storage device during its use in driving phases.

[0006] Several refrigerants have been used for this type of heat treatment system, such as Ri34a or Ri234yf. However, following new European standards, these refrigerants could be banned from use in Europe due to their environmental harm. For future heat treatment systems, it is planned to use R290 as a refrigerant. However, R290 is pure propane. As a safety precaution, it is therefore essential to avoid circulating propane directly in the ventilation, heating and / or air conditioning system. Thus, the heat treatment of the vehicle interior is done indirectly by the refrigerant, and only the heat transfer fluid circulates within the ventilation, heating and / or air conditioning system.

[0007] Within this type of circuit, an improvement in thermal performance is constantly being developed, particularly with the aim of improving the transfer of calories between the different fluids, or even improving the dissipation capacity of such calories.

[0008] The present invention falls within this context and as such proposes a heat transfer fluid circuit for a vehicle heat treatment system and intended to be traversed by a heat transfer fluid, comprising:

[0009] - a first loop comprising a first pumping device, a first heat exchanger and a second heat exchanger both configured to carry out a heat exchange between the heat transfer fluid and an air flow outside a passenger compartment of the vehicle, a third heat exchanger and a fourth heat exchanger both configured to carry out a heat exchange between the heat transfer fluid and a refrigerant circulating in a refrigerant circuit equipping said vehicle,

[0010] - a second loop comprising a fifth heat exchanger configured to carry out a heat exchange between the heat transfer fluid and the refrigerant circulating in the refrigerant circuit, a second pumping device and a sixth heat exchanger configured to carry out a heat exchange between the heat transfer fluid and an interior air flow intended to be sent into the passenger compartment of the vehicle, characterized in that the heat transfer fluid circuit comprises a first branch extending between a first junction point arranged on the first loop between the first heat exchanger and the second heat exchanger and a first convergence point arranged on the second loop downstream of the sixth heat exchanger and upstream of the fifth heat exchanger,a second branch extending between a first point of divergence arranged on the second loop downstream of the fifth heat exchanger and upstream of the sixth heat exchanger and a second point of convergence arranged on the first loop between the fourth heat exchanger and the first heat exchanger, and a third branch extending between the first point of junction and a third point of convergence arranged on the first loop between the third heat exchanger and the fourth heat exchanger.,

[0011] A heat transfer fluid circuit structured in this way thus makes it possible to improve the thermal performance of the heat treatment system with which said heat transfer fluid circuit is associated.

[0012] The first loop allows for improved dissipation of the calories captured by the heat transfer fluid. The first pumping device allows the heat transfer fluid to be circulated and the first heat exchanger and the second heat exchanger ensure dissipation of the calories from the heat transfer fluid via the outside air flow. The first heat exchanger and the second heat exchanger must therefore be positioned on a path of the outside air flow, for example by being arranged on the front of the vehicle in order to allow the outside air flow to pass through these two heat exchangers during the driving phase.

[0013] The third heat exchanger and the fourth heat exchanger improve the heat treatment of the refrigerant circulating in the refrigerant circuit. In fact, in the refrigerant circuit, the refrigerant circulates first within the fourth heat exchanger and then the third heat exchanger. The refrigerant is then under high pressure and high temperature and is therefore condensed as it passes through the fourth heat exchanger and the third heat exchanger, giving up its calories to the heat transfer fluid also passing through these heat exchangers.

[0014] Depending on the configuration of the heat treatment system, both the third and fourth heat exchangers can participate in the condensation of the refrigerant. In another example, the fourth heat exchanger can operate the condensation of the entire refrigerant while the third heat exchanger has a function of cooling the refrigerant.

[0015] The second loop's function is to provide air conditioning for the vehicle's passenger compartment. The second pumping device circulates the heat transfer fluid within this second loop, and the fifth heat exchanger cools the heat transfer fluid via the refrigerant. The latter, unlike when it passes through the third and fourth heat exchangers, is at low pressure and therefore captures the heat from the heat transfer fluid.

[0016] Once at low temperature, the heat transfer fluid then circulates within the sixth heat exchanger. The latter is crossed by the interior air flow, which drops in temperature by giving up its calories to the heat transfer fluid. The cooled interior air flow is then sent into the vehicle's passenger compartment to operate the air conditioning function. As such, the sixth heat exchanger is advantageously placed within a ventilation, heating and / or air conditioning system.

[0017] The first branch and the second branch ensure a fluid connection between the first loop and the second loop. This allows the operating modes of the heat transfer fluid circuit to be diversified and its thermal performance to be improved.

[0018] The first branch and the second branch allow in particular to fluidically connect the first heat exchanger and the fifth heat exchanger. In such a configuration, the outside air flow does not dissipate the calories of the heat transfer fluid but gives them to it. This subsequently allows to improve the performance of the heat exchange taking place in the fifth heat exchanger. A flow of heat transfer fluid having circulated within the first heat exchanger is at a high temperature at the inlet of the fifth heat exchanger, which promotes the evaporation of the refrigerant and thus optimizes a thermodynamic cycle of the latter. The third branch allows to distribute the heat exchanges of the heat transfer fluid. Thus the entirety of the heat transfer fluid circulating in the first loop circulates within the first heat exchanger.Then, upon reaching the first junction point, the heat transfer fluid can be divided into several fractions. Thus, a fraction of heat transfer fluid can continue its circulation in the first loop to circulate within the second heat exchanger and then the third heat exchanger while another fraction can circulate in the third branch to directly reach the fourth heat exchanger by bypassing the second heat exchanger and the third heat exchanger. The heat transfer fluid can also, from the first junction point, circulate in the first branch to reach the second loop. The heat transfer fluid is thus distributed within several sections of the first loop in order to optimize the thermal performance of the heat transfer fluid circuit as much as possible.

[0019] According to a characteristic of the invention, the heat transfer fluid circuit comprises a fourth branch extending between a second point of divergence arranged on the first loop between the fourth heat exchanger and the second point of convergence and a second junction point arranged on the first loop between the second heat exchanger and the third heat exchanger, the fourth branch comprising a seventh heat exchanger configured to carry out a heat exchange between the heat transfer fluid and the interior air flow.

[0020] Just like the sixth heat exchanger, the seventh heat exchanger is advantageously arranged in the ventilation, heating and / or air conditioning system in order to heat the interior air flow, in particular for the purpose of heating the passenger compartment of the vehicle. The fourth branch therefore begins downstream of the fourth heat exchanger so that the heat transfer fluid can capture the calories from the high-pressure refrigerant fluid in order to subsequently transfer them to the interior air flow by circulating within the seventh heat exchanger. The fourth branch then extends until it reaches the second junction point, upstream of the third heat exchanger. According to a characteristic of the invention, the heat transfer fluid circuit comprises a third loop comprising a third pumping device, an eighth heat exchanger configured to thermally treat an electric motor of the vehicle,a ninth heat exchanger configured to carry out a heat exchange between the heat transfer fluid and the refrigerant fluid circulating in the refrigerant circuit and a tenth heat exchanger configured to thermally treat an electrical storage device of the vehicle, the heat transfer fluid circuit comprising a fifth branch extending between the second junction point and a fourth point of convergence arranged downstream of the tenth heat exchanger and upstream of the eighth heat exchanger and a sixth branch extending between a third point of divergence arranged on the third loop between the eighth heat exchanger and the ninth heat exchanger and a fifth point of convergence arranged on the first loop between the first junction point and the second heat exchanger.,

[0021] The third loop is dedicated to the heat treatment of the vehicle's powertrain components. The eighth heat exchanger and the tenth heat exchanger are used to heat treat the electric motor and the electrical storage device respectively. The electric motor is likely to release heat during operation, for example when the vehicle is traveling at high speed, and needs to be cooled to regulate its temperature. The electrical storage device is also likely to release heat, for example after rapid recharging.

[0022] The ninth heat exchanger operates in the same way as the fifth heat exchanger, i.e. it allows cooling of the heat transfer fluid using the low-pressure refrigerant. The heat transfer fluid cooled within the ninth heat exchanger can then circulate to the eighth heat exchanger or to the tenth heat exchanger in order to heat treat the electric motor or the electrical storage device respectively if necessary. The fifth branch and the sixth branch allow the first loop to be fluidically connected to the third loop. Such a fluid connection is useful in particular for connecting the second heat exchanger to the eighth heat exchanger in order to passively heat treat the electric motor by capturing its calories and dissipating them via the second heat exchanger using the outside air flow.Generally speaking, the branches allowing the loops to be fluidically linked together make it possible to increase the number of functionalities of the heat transfer fluid circuit according to the invention.

[0023] According to a characteristic of the invention, the heat transfer fluid circuit comprises a seventh branch extending between a fourth point of divergence arranged on the third loop between the tenth heat exchanger and the fourth point of convergence and a sixth point of convergence arranged on the third loop between the third point of divergence and the ninth heat exchanger, the seventh branch comprising a fourth pumping device and an electric heating element. In other words, the seventh branch extends in parallel with a portion of the third loop comprising the third pumping device and the eighth heat exchanger.

[0024] The electric heating element provides additional heating of the heat transfer fluid. Such additional heating may be useful, for example, when the electrical storage device needs to be heated when the vehicle is started. More generally, the electric heating element is also used to heat the heat transfer fluid so that the latter promotes the evaporation of the refrigerant fluid subsequently by circulating within the ninth heat exchanger. Advantageously, the electric heating element is used when there is no other heat source available to provide an associated heat treatment function.

[0025] According to a characteristic of the invention, the heat transfer fluid circuit comprises an eighth branch extending between a fifth point of divergence arranged on the third loop between the ninth heat exchanger and the tenth heat exchanger and a seventh point of convergence arranged on the third loop between the tenth heat exchanger and the fourth point of divergence. In other words, the eighth branch is arranged in parallel with a portion of the first loop comprising the tenth heat exchanger.The eighth branch is useful in case of need to bypass the electrical storage device, for example for the purpose of cooling the electric motor within the eighth heat exchanger with coolant cooled within the ninth heat exchanger, or to improve the evaporation of the refrigerant by circulating heat transfer fluid, heated by the electric heating element, within the ninth heat exchanger without passing through the tenth heat exchanger while it is not necessary to heat treat the electrical storage device.

[0026] According to a feature of the invention, the first point of divergence and / or the second point of divergence and / or the third point of divergence and / or the fifth point of divergence comprise a bypass member. Such a bypass member may for example be a three-way valve making it possible to control towards which loop or branch the heat transfer fluid is directed from the first point of divergence and / or the second point of divergence and / or the third point of divergence and / or the fifth point of divergence.

[0027] According to a characteristic of the invention, the heat transfer fluid circuit comprises a ninth branch extending between a sixth point of divergence arranged on the first loop between the fourth heat exchanger and the first heat exchanger and an eighth point of convergence arranged on the third loop between the fifth point of divergence and the tenth heat exchanger, and a tenth branch extending between a seventh point of divergence arranged on the third loop between the tenth heat exchanger and the seventh point of convergence and a third junction point arranged on the fifth branch.The ninth branch and the tenth branch allow the tenth heat exchanger to be fluidically connected to the third and fourth heat exchangers, in order to be able to heat the electrical storage device using the calories captured by the heat transfer fluid within the third and fourth heat exchangers rather than using the electric heating element.

[0028] According to a feature of the invention, the sixth point of divergence comprises a bypass element. This bypass element is for example a three-way valve making it possible to direct the heat transfer fluid towards the first heat exchanger or towards the ninth branch depending on the need.

[0029] According to a characteristic of the invention, the first heat exchanger and the second heat exchanger are superimposed relative to each other in a direction of circulation of the outside air flow, the first heat exchanger being arranged downstream of the second heat exchanger relative to said direction of circulation of the outside air flow. Such a configuration makes it possible to improve the compactness of the heat transfer fluid circuit, in particular the section arranged at the front face of the vehicle, without disturbing the thermal capacities of the heat transfer fluid.

[0030] With respect to the direction of circulation of the outside air flow, the second heat exchanger is placed in front of the first heat exchanger because the heat transfer fluid circulating within the second heat exchanger is necessarily at a lower temperature than the heat transfer fluid circulating within the first heat exchanger. The outside air flow thus increases in temperature by passing through the second heat exchanger but in a sufficiently low manner to subsequently effectively thermally treat the heat transfer fluid circulating in the first heat exchanger by passing through the latter.

[0031] The invention also covers a heat treatment system comprising a heat transfer fluid circuit as described above and a refrigerant circuit. As previously mentioned, the refrigerant circuit and the heat transfer fluid circuit interact with each other to heat treat the passenger compartment of the vehicle and the elements of the vehicle's powertrain.

[0032] According to the direction of circulation of the refrigerant, the refrigerant is compressed and put under high pressure and high temperature in the gaseous state by a compression device, then passes through the fourth heat exchanger and the third heat exchanger in this order to be condensed and cooled by the heat transfer fluid circulating in the heat transfer fluid circuit.

[0033] Following this, the refrigerant circuit is divided into two paths and each of these paths includes an expansion member and, downstream of these, one of these paths includes the fifth heat exchanger while the other path includes the ninth heat exchanger. The expansion members are used to expand the refrigerant and lower it to low pressure and low temperature. The refrigerant is then evaporated within the fifth heat exchanger or the eighth heat exchanger while cooling the heat transfer fluid which also circulates there. Depending on the operating mode, the refrigerant can circulate in one of these paths or be divided into two fractions, each circulating in one of the paths.

[0034] Downstream of the heat exchangers ensuring the evaporation of the refrigerant, the two paths join and the evaporated refrigerant is compressed again by the compression device. The refrigerant circuit may optionally include an accumulation device in order to retain a non-evaporated liquid fraction so that it avoids damaging the compression device by passing through it. The refrigerant circuit may also include an internal heat exchanger operating a heat exchange between the high-pressure refrigerant and the low-pressure refrigerant in order to regulate the thermodynamic equilibrium of the refrigerant while improving the performance of the thermodynamic cycle of said refrigerant.

[0035] Other characteristics and advantages of the invention will become apparent from the following description on the one hand, and from several examples of embodiment given for informational and non-limiting purposes with reference to the attached schematic drawings on the other hand, in which:

[0036] [fig 1] represents a heat treatment system comprising a heat transfer fluid circuit according to the invention, [fig 2] represents a first mode of circulation of the fluids within said heat treatment system,

[0037] [fig 3] represents a second mode of circulation of fluids within said heat treatment system,

[0038] [fig 4] represents a third mode of circulation of fluids within said heat treatment system,

[0039] [fig 5] represents a fourth mode of circulation of fluids within said heat treatment system,

[0040] [fig 6] represents a heat treatment system comprising a variant of the heat transfer fluid circuit according to the invention,

[0041] [fig 7] represents a mode of circulation of fluids within the heat treatment system including the variant of the heat transfer fluid circuit.

[0042] The terms "upstream" and "downstream" used in the following description refer to the direction of circulation of the fluid in question, i.e. the refrigerant fluid or the heat transfer fluid.

[0043] In Figures 1 and 6, a heat transfer fluid circuit 2 is illustrated in solid lines and a plurality of sections of a refrigerant circuit 3 are illustrated in dotted lines. In Figures 2 to 5 and 7, for each of the circuits, the portions traversed by their respective fluid are in solid lines and the portions without fluid circulation are in dotted lines. The solid lines indicating the circulation of fluid are also of different thicknesses with respect to the refrigerant circuit 3 when the latter is used. More precisely, the thickest solid lines correspond to portions where the refrigerant circulates at high pressure and the thinnest solid lines correspond to portions where the refrigerant circulates at low pressure.

[0044] Figure 1 represents a heat treatment system 1 that can be integrated within a motor vehicle and comprising a first embodiment of a heat transfer fluid circuit 2 according to the invention. This heat treatment system 1 is capable of providing heat treatment of the passenger compartment of the vehicle, but also heat treatment of different components of a powertrain of the vehicle.

[0045] To do this, the heat treatment system comprises the heat transfer fluid circuit 2 in which a heat transfer fluid circulates, and a refrigerant circuit 3 in which a refrigerant circulates. The heat treatment system 1 is configured to operate different interactions between the heat transfer fluid and the refrigerant in order to optimally heat treat the passenger compartment of the vehicle and the various components of the vehicle's powertrain. The heat transfer fluid may for example be glycolated water, while the refrigerant may advantageously be a fluid of type R290, i.e. propane, meeting European environmental protection standards unlike other types of refrigerant used for heat treatment.

[0046] The heat transfer fluid circuit 2 is divided into several fluidically linked sections in order to multiply the functionalities of the heat treatment system 1.

[0047] The heat transfer fluid circuit 2 therefore comprises a first loop 4. This first loop 4 is provided with a first pumping device 5, a first heat exchanger 6, a second heat exchanger 7, a third heat exchanger 8 and a fourth heat exchanger 9.

[0048] The first pumping device 5 has the function of circulating the heat transfer fluid. The first heat exchanger 6 and the second heat exchanger 7 are configured to carry out a heat exchange between the heat transfer fluid circulating therein and an outside air flow 10 passing through them. By outside air flow, it is necessary to understand an air flow which is not intended to be sent into the passenger compartment of the vehicle. In order to be positioned at a path of the outside air flow 10, the first heat exchanger 6 and the second heat exchanger 7 may for example be arranged at a front face of the vehicle.In Figure 1 and the following figures, the first heat exchanger 6 and the second heat exchanger 7 are spaced apart from each other for reasons of clarity of the figures, but advantageously, the first heat exchanger 6 and the second heat exchanger 7 are superimposed relative to each other in a direction of the external air flow so that an external air flow 10 passes through the first heat exchanger 6 and the second heat exchanger 7 in series.

[0049] The third heat exchanger 8 and the fourth heat exchanger 9 are configured to carry out a heat exchange between the heat transfer fluid circulating therein and the refrigerant circulating in the refrigerant circuit 3.

[0050] The direction of circulation between the two fluids is reversed with respect to each other: the heat transfer fluid circulates in the third heat exchanger 8 then in the fourth heat exchanger 9, while the refrigerant fluid circulates in the fourth heat exchanger 9 then in the third heat exchanger 8.

[0051] At this stage of the refrigerant circuit 3, the refrigerant is at high pressure and high temperature. Within the third heat exchanger 8 and the fourth heat exchanger 9, the calories are therefore transferred from the refrigerant to the heat transfer fluid. The heat exchanges taking place in the first heat exchanger 6 and in the second heat exchanger 7 via the outside air flow 10 can in particular make it possible to dissipate these calories captured by the heat transfer fluid.

[0052] The heat transfer fluid circuit 2 also comprises a second loop 11 within which the heat transfer fluid can also circulate. The second loop 11 comprises a second pumping device 12, a fifth heat exchanger 13 and a sixth heat exchanger 14. Just like the first pumping device 5, the second pumping device 12 makes it possible to circulate the heat transfer fluid.

[0053] The fifth heat exchanger 13 is configured to carry out a heat exchange between the heat transfer fluid circulating in the second loop 11 and the refrigerant fluid circulating in the refrigerant circuit 3. Unlike the heat exchange taking place in the third heat exchanger 8 and in the fourth heat exchanger 9, the heat exchange taking place within the fifth heat exchanger

[0054] 13 is done with the refrigerant fluid at low pressure and low temperature, thus allowing the heat transfer fluid to be cooled.

[0055] The sixth heat exchanger 14 is configured to carry out a heat exchange between the heat transfer fluid and an interior air flow 15. Unlike the exterior air flow 10, the interior air flow 15 is intended to be sent to the passenger compartment of the vehicle in order to thermally treat it. As such, the sixth heat exchanger 14 can be arranged within a ventilation, heating and / or air conditioning installation which makes it possible to direct the interior air flow 15 through in particular the sixth heat exchanger.

[0056] 14 before sending it to the passenger compartment of the vehicle. Within the sixth heat exchanger 14, the heat transfer fluid captures the calories from the interior air flow 15 and the latter is subsequently sent cooled in order to air condition the passenger compartment of the vehicle.

[0057] Within the heat transfer fluid circuit 2, the first loop 4 and the second loop 11 are fluidically linked together by a first branch 16 and by a second branch 17. The first branch 16 begins at a first junction point 18 arranged on the first loop 4 between the first heat exchanger 6 and the second heat exchanger 7 and extends to a first convergence point 19 arranged on the second loop 11 downstream of the sixth heat exchanger 14 and upstream of the fifth heat exchanger 13. The heat transfer fluid can thus circulate from the first loop 4 to the second loop 11 via this first branch 16.

[0058] The second branch 17 begins at a first point of divergence 20 arranged on the second loop 11 downstream of the fifth heat exchanger 13 and upstream of the sixth heat exchanger 14 and extends to a second point of convergence 21 arranged on the first loop 4 between the fourth heat exchanger 9 and the first heat exchanger 6. It is thus understood that the first branch 16 and the second branch 17 allow in particular a fluid connection between the first heat exchanger 6 and the fifth heat exchanger 13. As will be described later, such a configuration is useful for the heat treatment of the vehicle.

[0059] The heat transfer fluid circuit 2 further comprises a third branch 22 extending between the first junction point 18 and a third convergence point 23 arranged on the first loop 4 between the third heat exchanger 8 and the fourth heat exchanger 9. The third branch 22 makes it possible to directly connect the first heat exchanger 6 to the fourth heat exchanger 9, bypassing the second heat exchanger 7 and the third heat exchanger 8.

[0060] The heat transfer fluid circuit 2 also comprises a fourth branch 24 extending between a second point of divergence 25 arranged on the first loop 4 between the fourth heat exchanger 9 and the second point of convergence 21 and a second junction point 26 arranged on the first loop 4 between the second heat exchanger 7 and the third heat exchanger 8. The fourth branch 24 comprises a seventh heat exchanger 27 configured to carry out a heat exchange between the heat transfer fluid and the interior air flow 15. Just like the sixth heat exchanger 14, the seventh heat exchanger 27 is advantageously arranged within the ventilation, heating and / or air conditioning installation mentioned above. As will be detailed later, the seventh heat exchanger 27 participates in heating the passenger compartment of the vehicle.

[0061] The heat transfer fluid circuit 2 also comprises a third loop 28. This third loop 28 is dedicated to the thermal regulation of the elements of a vehicle's powertrain. The third loop 28 comprises a third pumping device 29, an eighth heat exchanger 30, a ninth heat exchanger 31 and a tenth heat exchanger 32.

[0062] The eighth heat exchanger 30 allows heat treatment of an electric motor of the vehicle by the heat transfer fluid. By circulating in the eighth heat exchanger 30, the heat transfer fluid is thus able to heat or cool the electric motor depending on their respective temperatures.

[0063] The ninth heat exchanger 31, like the fifth heat exchanger 13, is configured to carry out a heat exchange between the heat transfer fluid circulating in the second loop 11 and the low pressure and low temperature refrigerant fluid circulating in the refrigerant circuit 3.

[0064] The tenth heat exchanger 32 allows heat treatment of an electrical storage device of the vehicle by the heat transfer fluid. By circulating in the tenth heat exchanger 32, the heat transfer fluid is thus able to heat or cool the electrical storage device depending on their respective temperature.

[0065] The first loop 4 and the third loop 28 are fluidly connected to each other by a fifth branch 33 and by a sixth branch 34. The fifth branch 33 extends between the second junction point 26 and a fourth point of convergence 35 arranged on the third loop 28 downstream of the tenth heat exchanger 32 and upstream of the eighth heat exchanger 30. The seventh branch 34 extends between a third point of divergence 36 arranged on the third loop 28 between the eighth heat exchanger 30 and the ninth heat exchanger 31 and a fifth point of convergence 37 arranged on the first loop 28 between the first junction point 18 and the second heat exchanger 7. The fifth branch 33 and the sixth branch 34 make it possible in particular to fluidly connect the second heat exchanger 7 and the eighth heat exchanger 30.

[0066] The heat transfer fluid circuit 2 comprises a seventh branch 38 extending between a fourth point of divergence 39 arranged on the third loop 28 between the tenth heat exchanger 32 and the fourth point of convergence 35 and a sixth point of convergence 40 arranged on the third loop 28 between the third point of divergence 36 and the ninth heat exchanger 31. The seventh branch 38 further comprises a fourth pumping device 41 and an electric heating element 42. The fourth pumping device 41 allows the circulation of the heat transfer fluid in the seventh branch 38. The electric heating element 42 ensures additional heating of the heat transfer fluid when needed.

[0067] Finally, the heat transfer fluid circuit 2 comprises an eighth branch 43 extending between a fifth point of divergence 44 arranged on the third loop 28 between the ninth heat exchanger 31 and the tenth heat exchanger 32 and a seventh point of convergence 45 arranged on the third loop 28 between the tenth heat exchanger 32 and the fourth point of divergence 39. The eighth branch 43 is thus arranged in parallel with the tenth heat exchanger 32 and allows the heat transfer fluid to bypass the latter.

[0068] Several points of divergence of the heat transfer fluid circuit, for example the first point of divergence 20, the second point of divergence 25, the third point of divergence 36 and the fifth point of divergence 44, may comprise a bypass element 46. Such a bypass element 46 may be in the form of a three-way valve making it possible to determine a circulation of the heat transfer fluid. The heat transfer fluid circuit 2 may also comprise one or more non-return valves 47 authorizing the circulation of the heat transfer fluid in one direction of circulation but prohibiting it in the opposite direction of circulation.

[0069] The refrigerant circuit 3 is only partially shown in the figures, but the essential elements of the latter are shown therein. The refrigerant circuit 3 comprises a main path 48 provided with a compression device 49, the third heat exchanger 8 and the fourth heat exchanger 9. The refrigerant circulating in the main path 48 passes in order through the fourth heat exchanger 9 then the third heat exchanger 8.

[0070] Downstream of the third heat exchanger 8, the main path 48 divides into a first path 50 and a second path 51. The first path comprises a first expansion member 52 and the fifth heat exchanger 13 while the second path 51 comprises a second expansion member 53 and the ninth heat exchanger 31. The first path 50 and the second path 51 then join to form the main path 48 again.

[0071] Figure 2 illustrates a first mode of operation of the heat treatment system 1 illustrated in Figure 1. In this first mode of operation, the objective is to operate air conditioning of the passenger compartment of the vehicle as well as cooling of the electrical storage device.

[0072] For this, the refrigerant circulating in the refrigerant circuit 3 is compressed by the compression device 49 then circulates within the fourth heat exchanger 9 then the third heat exchanger 8 to be condensed.

[0073] The refrigerant fluid is then divided into two fractions. A first fraction circulates in the first path 50 and a second fraction circulates in the second path 51. The first fraction is expanded to low pressure by the first expansion member 52 then circulates within the fifth heat exchanger 13 to cool the heat transfer fluid circulating in the second loop 11. The latter is circulated by the second pumping device 12 and is cooled within the fifth heat exchanger 13. The cooled heat transfer fluid then circulates within the sixth heat exchanger 14 and captures the calories from the interior air flow 15 which is cooled and sent to the passenger compartment of the vehicle to provide the air conditioning function.

[0074] The second fraction is expanded to low pressure by the second expansion member 53 and circulates within the ninth heat exchanger 31 to cool the heat transfer fluid circulating in the third loop 28. The latter is circulated by the fourth pumping device 41 and is cooled within the ninth heat exchanger 31. The cooled heat transfer fluid then circulates within the tenth heat exchanger 32 in order to cool the electrical storage device. The latter is indeed likely to release heat during its operation, for example after rapid recharging. The cold heat transfer fluid thus makes it possible to capture the calories released by the electrical storage device. In order to promote the evaporation of the refrigerant circulating in the ninth heat exchanger 31, the heat transfer fluid can be heated by the electric heating element 42 before circulating within the ninth heat exchanger.

[0075] In order for the refrigerant to be expanded and to effectively cool the heat transfer fluid, condensation and possible pre-cooling are essential. For this reason, the refrigerant is condensed by the heat transfer fluid during the heat exchange taking place in the fourth heat exchanger 9 and possibly in the third heat exchanger 8.

[0076] In order to promote the condensation of the refrigerant fluid, the heat transfer fluid also circulates in the first loop 4 by being circulated by the first pumping device 5 and then circulates within the first heat exchanger 6. At the outlet of the latter, the heat transfer fluid divides into two fractions at the first junction point 18.

[0077] The first fraction continues its circulation in the first loop 4 and circulates within the second heat exchanger 7, then the third heat exchanger 8. The second fraction circulates in the third branch 22, directly joins the first fraction upstream of the fourth heat exchanger 9 and the two fractions circulate within the latter.

[0078] It is thus understood that the heat transfer fluid allows the refrigerant fluid to be condensed by circulating in the third heat exchanger 8 and in the fourth heat exchanger 9. The heat transfer fluid then captures the calories from the refrigerant fluid and these calories are subsequently dissipated thanks to the flow of outside air 10 when the heat transfer fluid circulates in the first heat exchanger 6 and in the second heat exchanger 7. However, only a portion of the heat transfer fluid circulates in the second heat exchanger 7 and in the third heat exchanger 8. This allows two-stage condensation or condensation then cooling (or “sub-cooling”) of the refrigerant fluid when it circulates within the fourth heat exchanger 9 then the third heat exchanger 8 in order to improve the performance of the heat treatment system i.

[0079] As mentioned previously, the first heat exchanger 6 and the second heat exchanger 7 are superimposed relative to each other relative to the direction of circulation of the outside air flow 10. The latter thus initially passes through the second heat exchanger 7 and then the first heat exchanger 6. The heat transfer fluid circulating within the second heat exchanger 7 is necessarily at a lower temperature than the heat transfer fluid circulating within the first heat exchanger 6, the outside air flow 10 thus increases in temperature by passing through the second heat exchanger 7 but in a sufficiently low manner to subsequently effectively thermally treat the heat transfer fluid circulating in the first heat exchanger 6 by passing through the latter.

[0080] Figure 3 shows a second mode of operation of the heat treatment system 1. This second mode of operation has the same objectives as the first mode of operation, namely to air-condition the passenger compartment of the vehicle and to cool the electrical storage device, but also allows passive cooling of the electric motor. Only this function will be described and reference will be made to the description of Figure 2 for the elements common to the first mode of operation and the second mode of operation.

[0081] According to this second mode of operation, the electric motor also needs to be cooled, as it is likely to release heat during its operation, for example when the vehicle is traveling at moderate speed. The third pumping device 29 therefore circulates the heat transfer fluid which then circulates within the eighth heat exchanger 30 separately from the heat transfer fluid responsible for cooling the electrical storage device. The heat transfer fluid thus captures the calories generated by the electric motor and subsequently circulates in the sixth branch 34 via the third divergence point 36 in order to join the first loop 4. This having been done, the heat transfer fluid circulates within the second heat exchanger 7, joining the fraction of heat transfer fluid thermally treating the refrigerant fluid within the third heat exchanger 8.Thus the calories captured from the electric motor by the heat transfer fluid are dissipated by the external air flow 10.

[0082] At the outlet of the second heat exchanger 7, part of the heat transfer fluid circulates within the fifth branch 33 until it again reaches the eighth heat exchanger 30 to cool the electric motor.

[0083] Figure 4 illustrates a third mode of operation of the heat treatment system 1. The objective of this third mode of operation is to dehumidify the passenger compartment of the vehicle while passively cooling the electric motor. The dehumidification consists of firstly cooling the interior air flow 15 via the sixth heat exchanger 14 to condense the humidity contained in the interior air flow 15 and retain it, then secondly heating the interior air flow 15 using the seventh heat exchanger 27 to send hot and dry air into the passenger compartment of the vehicle.

[0084] For this, as described in figure 2, the heat transfer fluid circulates in the second loop 11 to be cooled by the refrigerant fluid within the fifth heat exchanger 13 and subsequently cool the interior air flow 15 within the sixth heat exchanger 14.

[0085] In parallel, the heat transfer fluid is also circulated in the first loop 4 and rises in temperature by condensing the refrigerant fluid within at least the fourth heat exchanger 9. The hot refrigerant fluid subsequently separates into two fractions at the second point of divergence 25. A first fraction circulates in the fourth branch 24 up to the seventh heat exchanger 27 and transfers the calories captured in at least the fourth heat exchanger 9 to the interior air flow 15. At the outlet of the seventh heat exchanger 27, the heat transfer fluid continues its circulation in the fourth branch 24 and joins the first loop 4 via the second junction point 26. The dehumidification function is thus implemented.

[0086] The second fraction circulates within the first heat exchanger 6 in which the calories are dissipated by the flow of outside air 10. The entirety of said heat transfer fluid then circulates within the third branch 22 to reach the fourth heat exchanger 9-

[0087] Just as described for the second operating mode, the electric motor is passively cooled thanks to the fluid connection, via the fifth branch 33 and the sixth branch 34, between the eighth heat exchanger 30 where the calories of the heat engine are captured by the heat transfer fluid and the second heat exchanger 7 where the calories captured by the heat transfer fluid are dissipated by the outside air flow 10.

[0088] The fraction circulating in the fourth branch 24 and within the second heat exchanger 7 thus join at the second junction point 26. A fraction then circulates within the fifth branch 33 to cool the electric motor. The other fraction passes through the third heat exchanger 8 and the calories lost by the heat transfer fluid within the second heat exchanger 7 or the seventh heat exchanger 27 allow optimal cooling or condensation of the refrigerant fluid circulating in the main path 48 and circulating in particular within the third heat exchanger 8.

[0089] It should be noted that, concerning this third mode of operation, the refrigerant fluid does not circulate in the second channel 51 because it is not necessary to operate the ninth heat exchanger 31.

[0090] Figure 5 represents a fourth mode of operation of the heat treatment system 1 according to the invention. This fourth mode of operation allows the heating of the passenger compartment of the vehicle and implements in parallel several means of improving the performance of the thermodynamic cycle of the refrigerant fluid, in particular at the level of its evaporation. Concerning the heating of the passenger compartment, the heat transfer fluid is heated thanks to the high temperature refrigerant fluid and the heat exchange taking place in the third heat exchanger 8 and in the fourth heat exchanger 9. Then the refrigerant fluid circulates in the fourth branch 24 to heat the interior air flow 15 thanks to the seventh heat exchanger 27.

[0091] Heating the vehicle interior allows the refrigerant to condense. To complete the thermodynamic cycle, the refrigerant must then be efficiently evaporated by circulating within the fifth heat exchanger 13 and / or the ninth heat exchanger 31. In the case where no element needs to be cooled, as illustrated in Figure 5, another heat source must be used to promote the evaporation of the refrigerant.

[0092] At the fifth heat exchanger 13, the heat transfer fluid circulates between the latter and the first heat exchanger 6 thanks to the first branch 16 and the second branch 17. The heat transfer fluid is thus heated by the outside air flow 10 and subsequently circulates within the fifth heat exchanger 13 to evaporate the refrigerant which circulates in the first path 50.

[0093] The refrigerant fluid is also evaporated within the ninth heat exchanger 31 by circulating in the second path 51. To promote this evaporation, the heat transfer fluid can circulate within the eighth heat exchanger 30 to capture the calories released by the electric motor. The heat transfer fluid can also circulate within the seventh branch 38 to be heated by the electric heating element 42. The heat transfer fluid is thus at a sufficient temperature to transfer its calories to the refrigerant fluid so that the latter evaporates during the heat exchange taking place in the ninth heat exchanger 31. Since the electrical storage device does not need to be heat treated, the heat transfer fluid bypasses the tenth heat exchanger 32 by circulating in the eighth branch 43 at the outlet of the ninth heat exchanger 31.However, if heat is available in the electrical storage device although it does not need to be cooled, the heat transfer fluid can circulate in the heat exchanger 32 to recover this available heat.

[0094] Figure 6 represents a variant of the heat transfer fluid circuit 2. Only the structural and functional characteristics specific to this variant will be described here and reference will be made to the description of Figure 1 for the characteristics common to the heat transfer fluid circuit 2 and its variant.

[0095] The variant illustrated in Figure 6 differs from what has been described previously in that the heat transfer fluid circuit 2 comprises a ninth branch 54 extending between a sixth point of divergence 55 arranged on the first loop 4 between the fourth heat exchanger 9 and the first heat exchanger 6 and an eighth point of convergence 56 arranged on the third loop 28 between the fifth point of divergence 44 and the tenth heat exchanger 32, and a tenth branch 57 extending between a seventh point of divergence 58 arranged on the third loop 28 between the tenth heat exchanger 32 and the seventh point of convergence 45 and a third junction point 59 arranged on the fifth branch 33.

[0096] The ninth branch 54 and the tenth branch 57 make it possible to fluidly connect the third heat exchanger 8 and the fourth heat exchanger 9 to the tenth heat exchanger 32. This makes it possible to heat the electrical storage device using the calories captured by the heat transfer fluid during the heat exchanges taking place in the third heat exchanger 8 and in the fourth heat exchanger 9. The electrical storage device may in fact need to be heated, for example when starting the vehicle and / or in the event of low ambient temperature.

[0097] The sixth divergence point 55 may also comprise a bypass element 46 which may be in the form of a three-way valve. In Figures 6 and 7, the sixth divergence point 55 is arranged between the second divergence point 25 and the second convergence point 21, but it may also be positioned between the fourth heat exchanger 9 and the second divergence point 25. Alternatively, the second divergence point 25 and the sixth divergence point 55 may also be combined into a single module for directing the heat transfer fluid to the fourth branch 24 and / or to the ninth branch 54 and / or to the first heat exchanger 6.

[0098] Figure 7 represents a circulation mode of the heat treatment system 1 comprising the variant of the heat transfer fluid circuit. This circulation mode is similar to the fourth circulation mode represented in Figure 5 but exploiting the structural and functional characteristics specific to the variant. Reference will therefore be made to the description in Figure 5 for the fluid circulations common to the two circulation modes.

[0099] In addition to heating the passenger compartment of the vehicle and improving the performance of the thermodynamic cycle with a heat supply from the first heat exchanger 6, the electric motor and the electric heating element 42, the heat treatment system 1 also heats the electrical storage device.

[0100] For this, the heat transfer fluid circulating in the first loop is heated by circulating in the third heat exchanger 8 and in the fourth heat exchanger 9 is sent partly within the fourth branch 24 as described previously, but also within the ninth branch 54. The heat transfer fluid then circulates to the tenth heat exchanger 32 in order to transfer its calories to the electrical storage device to heat the latter. At the outlet of the tenth heat exchanger 32, the heat transfer fluid circulates within the tenth branch 57 until it reaches the fifth branch 33. The difference with what has been described previously is that the heat transfer fluid circulates in the fifth branch 33 in a direction of circulation opposite to what has been described in figure 3 or 4 for example.The heat transfer fluid therefore circulates here towards the first loop 4 from the third junction point 59 to the second junction point 26, in order to circulate again within the third heat exchanger 8 and the fourth heat exchanger 9. The variant of the heat transfer fluid circuit 2 thus makes it possible to exploit the calories captured within the third heat exchanger 8 and the fourth heat exchanger 9 to heat the electrical storage device.

[0101] Of course, the invention is not limited to the examples which have just been described and numerous adjustments can be made to these examples without departing from the scope of the invention.

[0102] The invention, as just described, achieves the aim it set for itself, and makes it possible to propose a heat transfer fluid circuit ensuring an improvement in the thermal performance of the treatment system with which said heat transfer fluid circuit is associated. Variants not described here could be implemented without departing from the context of the invention, provided that, in accordance with the invention, they comprise a heat transfer fluid circuit in accordance with the invention.

Claims

CLAIMS i- Heat transfer fluid circuit (2) for a heat treatment system (1) of a vehicle and intended to be traversed by a heat transfer fluid, comprising: a first loop (4) comprising a first pumping device (5), a first heat exchanger (6) and a second heat exchanger (7) both configured to carry out a heat exchange between the heat transfer fluid and an air flow (10) outside a passenger compartment of the vehicle, a third heat exchanger (8) and a fourth heat exchanger (9) both configured to carry out a heat exchange between the heat transfer fluid and a refrigerant circulating in a refrigerant circuit (3) equipping said vehicle, a second loop (11) comprising a fifth heat exchanger (13) configured to carry out a heat exchange between the heat transfer fluid and the refrigerant circulating in the refrigerant circuit,a second pumping device (12) and a sixth heat exchanger (14) configured to carry out a heat exchange between the heat transfer fluid and an interior air flow (15) intended to be sent into the passenger compartment of the vehicle, characterized in that the heat transfer fluid circuit (2) comprises a first branch (16) extending between a first junction point (18) arranged on the first loop (4) between the first heat exchanger (6) and the second heat exchanger (7) and a first convergence point (19) arranged on the second loop (11) downstream of the sixth heat exchanger (14) and upstream of the fifth heat exchanger (13),a second branch (17) extending between a first point of divergence (20) arranged on the second loop (11) downstream of the fifth heat exchanger (13) and upstream of the sixth heat exchanger (14) and a second point of convergence (21) arranged on the first loop (4) between the fourth heat exchanger (9) and the first heat exchanger (6), and a third branch (22) extending between the first junction point (18) and a third point of convergence (23) arranged on the first loop, (4) between the third heat exchanger (8) and the fourth heat exchanger (9). 2- Heat transfer fluid circuit (2) according to claim 1, comprising a fourth branch (24) extending between a second point of divergence (25) arranged on the first loop (4) between the fourth heat exchanger (9) and the second point of convergence (21) and a second junction point (26) arranged on the first loop (4) between the second heat exchanger (7) and the third heat exchanger (8), the fourth branch (24) comprising a seventh heat exchanger (27) configured to carry out a heat exchange between the heat transfer fluid and the interior air flow (15). 3- Heat transfer fluid circuit (2) according to claim 2, comprising a third loop (28) comprising a third pumping device (29), an eighth heat exchanger (30) configured to thermally treat an electric motor of the vehicle, a ninth heat exchanger (31) configured to carry out a heat exchange between the heat transfer fluid and the refrigerant circulating in the refrigerant circuit (3) and a tenth heat exchanger (32) configured to thermally treat an electrical storage device of the vehicle,the heat transfer fluid circuit (2) comprising a fifth branch (33) extending between the second junction point (26) and a fourth convergence point (35) arranged downstream of the tenth heat exchanger (32) and upstream of the eighth heat exchanger (30) and a sixth branch (34) extending between a third divergence point (36) arranged on the third loop (28) between the eighth heat exchanger (30) and the ninth heat exchanger (31) and a fifth convergence point (37) arranged on the first loop (4) between the first junction point (18) and the second heat exchanger (7)., 4- Heat transfer fluid circuit (2) according to the preceding claim, comprising a seventh branch (38) extending between a fourth point of divergence (39) arranged on the third loop (28) between the tenth heat exchanger (32) and the fourth point of convergence (35) and a sixth point of convergence (40) arranged on the third loop (28) between the third point of divergence (36) and the ninth heat exchanger (31), the seventh branch (38) comprising a fourth pumping device (41) and an electric heating element (42). 5- Heat transfer fluid circuit (2) according to the preceding claim, comprising an eighth branch (43) extending between a fifth point of divergence (44) arranged on the third loop (28) between the ninth heat exchanger (31) and the tenth heat exchanger (32) and a seventh point of convergence (45) arranged on the third loop (28) between the tenth heat exchanger (32) and the fourth point of divergence (39)- 6- Heat transfer fluid circuit (2) according to the preceding claim, in which the first point of divergence (20) and / or the second point of divergence (25) and / or the third point of divergence (36) and / or the fifth point of divergence (44) comprise a bypass member (46). 7- Heat transfer fluid circuit (2) according to claim 5 or 6, comprising a ninth branch (54) extending between a sixth point of divergence (55) arranged on the first loop (4) between the fourth heat exchanger (9) and the first heat exchanger (6) and an eighth point of convergence (56) arranged on the third loop (28) between the fifth point of divergence (44) and the tenth heat exchanger (32), and a tenth branch (57) extending between a seventh point of divergence (58) arranged on the third loop (28) between the tenth heat exchanger (32) and the seventh point of convergence (45) and a third junction point (59) arranged on the fifth branch (33). 8- Heat transfer fluid circuit (2) according to the preceding claim, in which the sixth point of divergence (55) comprises a bypass element (46). 9- Heat transfer fluid circuit (2) according to any one of the preceding claims, in which the first heat exchanger (6) and the second heat exchanger (7) are superimposed relative to each other in a direction of circulation of the external air flow (10), the first heat exchanger (6) being arranged downstream of the second exchanger thermal (7) relative to said direction of circulation of the external air flow (10). 10- Heat treatment system (1) of a vehicle, comprising a heat transfer fluid circuit (2) according to any one of the preceding claims and a refrigerant fluid circuit (3).

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