Heat transfer fluid circuit for a vehicle's heat treatment system

Abstract

Heat transfer fluid circuit for a vehicle thermal treatment system. 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), characterized 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). (Figure 1)

Description

Title of the invention: Heat transfer fluid circuit for a vehicle's heat treatment system

[0001] The present invention relates to the field of heat treatment systems of a motor vehicle, and more particularly concerns a heat transfer fluid circuit integrated into such heat treatment systems.

[0002] Motor vehicles are commonly equipped with a refrigerant circuit and at least one heat transfer fluid circuit, both used to contribute to the thermal treatment of different areas or components of the vehicle. It is particularly known to use the refrigerant circuit and / or the heat transfer fluid circuit to thermally treat an airflow sent into the passenger compartment of a vehicle equipped with such a circuit. This thermal treatment is achieved, in particular, by circulating the refrigerant within a ventilation, heating, and / or air conditioning system installed in the vehicle.

[0003] 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 propelling the vehicle. The heat treatment system thus provides the energy needed to cool the electrical storage device during its use in driving phases.

[0004] Several refrigerants have been used for this type of heat treatment system, such as R134a or R1234yf. However, due to new European standards, these refrigerants may be banned from use in Europe because of their environmental impact. For future heat treatment systems, the use of R290 as the refrigerant is being considered. 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 vehicle's interior is heated indirectly by the refrigerant, and only the heat transfer fluid circulates within the ventilation, heating, and / or air conditioning system.

[0005] Within this type of circuit, improvements in thermal performance are constantly being developed, particularly with the aim of improving heat transfer between different fluids, or improving the capacity to dissipate such heat.

[0006] The present invention falls within this context and, as such, proposes a heat transfer fluid circuit for a vehicle heat treatment system, intended to be traversed by a heat transfer fluid, comprising: - a first loop comprising a first pumping device, a first heat exchanger and a second heat exchanger both configured to operate a heat exchange between the heat transfer fluid and an outside airflow to a vehicle passenger compartment, a third heat exchanger and a fourth heat exchanger both configured to operate a heat exchange between the heat transfer fluid and a refrigerant circulating in a refrigerant circuit equipping said vehicle, - a second loop comprising a fifth heat exchanger configured to perform 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 perform heat exchange between the heat transfer fluid and an interior airflow intended to be sent into the vehicle's passenger compartment,

[0007] characterized in that the heat transfer fluid circuit comprises a first branch extending between a first junction point disposed on the first loop between the first heat exchanger and the second heat exchanger and a first convergence point disposed on the second loop downstream of the sixth heat exchanger and upstream of the fifth heat exchanger, a second branch extending between a first divergence point disposed on the second loop downstream of the fifth heat exchanger and upstream of the sixth heat exchanger and a second convergence point disposed on the first loop between the fourth heat exchanger and the first heat exchanger, and a third branch extending between the first junction point and a third convergence point disposed on the first loop between the third heat exchanger and the fourth heat exchanger.

[0008] A heat transfer fluid circuit structured in this way thus makes it possible to improve the thermal performance of the heat treatment system to which said heat transfer fluid circuit is associated.

[0009] The first loop allows for improved dissipation of the heat absorbed by the heat transfer fluid. The first pumping device circulates the heat transfer fluid, and the first and second heat exchangers ensure that the heat from the heat transfer fluid is dissipated via the outside airflow. The first and second heat exchangers must therefore be positioned along the path of the outside airflow, for example by being arranged at the front of the vehicle to allow the outside airflow to pass through these two heat exchangers during driving.

[0010] The third and fourth heat exchangers improve the thermal treatment of the refrigerant circulating in the refrigerant circuit. In the refrigerant circuit, the refrigerant first circulates through the fourth heat exchanger and then through the third heat exchanger. The refrigerant is then under high pressure and high temperature and is therefore condensed as it passes through the fourth and third heat exchangers, transferring its heat to the heat transfer fluid also flowing through these heat exchangers.

[0011] 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 perform the complete condensation of the refrigerant on its own, while the third heat exchanger acts as a refrigerant cooler.

[0012] The second loop's function is, in particular, 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 using the refrigerant. Unlike when it passes through the third and fourth heat exchangers, the refrigerant is at low pressure here and therefore absorbs heat from the heat transfer fluid.

[0013] Once at a low temperature, the heat transfer fluid then circulates within the sixth heat exchanger. The interior airflow passes through this exchanger, lowering its temperature and transferring heat to the heat transfer fluid. The cooled interior airflow is then sent into the vehicle's passenger compartment to perform the air conditioning function. As such, the sixth heat exchanger is advantageously located within a ventilation, heating, and / or air conditioning system.

[0014] The first and second branches ensure a fluidic connection between the first and second loops. This allows for diversification of the operating modes of the heat transfer fluid circuit and improves its thermal performance.

[0015] The first and second branches allow, in particular, for the fluid connection of the first heat exchanger and the fifth heat exchanger. In such a configuration, the outside airflow does not dissipate heat from the heat transfer fluid but rather transfers it to it. This subsequently improves 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 thermal 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.

[0016] The third branch allows for the distribution of heat exchange within the heat transfer fluid. Thus, all of the heat transfer fluid circulating in the first loop flows through the first heat exchanger. Then, upon reaching the first junction point, the heat transfer fluid can be divided into several fractions. One fraction of the heat transfer fluid can continue circulating in the first loop to pass through the second and then the third heat exchanger, while another fraction can flow through the third branch to directly reach the fourth heat exchanger, bypassing the second and third heat exchangers. The heat transfer fluid can also, from the first junction point, flow through 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.

[0017] According to one feature of the invention, the heat transfer fluid circuit comprises a fourth branch extending between a second divergence point disposed on the first loop between the fourth heat exchanger and the second convergence point and a second junction point disposed on the first loop between the second heat exchanger and the third heat exchanger, the fourth branch comprising a seventh heat exchanger configured to operate a heat exchange between the heat transfer fluid and the internal airflow.

[0018] Just like the sixth heat exchanger, the seventh heat exchanger is advantageously positioned in the ventilation, heating, and / or air conditioning system to heat the interior airflow, particularly for the purpose of heating the vehicle's passenger compartment. The fourth branch therefore begins downstream of the fourth heat exchanger so that the heat transfer fluid can absorb heat from the high-pressure refrigerant and then transfer it to the interior airflow as it circulates through the seventh heat exchanger. The fourth branch then extends to the second junction point, upstream of the third heat exchanger.

[0019] According to one feature of the invention, the heat transfer fluid circuit comprises a third loop including a third pumping device, an eighth heat exchanger configured to thermally treat an electric motor of the vehicle, a ninth heat exchanger configured to perform heat exchange between the heat transfer fluid and the refrigerant circulating in the refrigerant circuit, and a tenth heat exchanger configured to treat thermally 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 convergence point located downstream of the tenth heat exchanger and upstream of the eighth heat exchanger and a sixth branch extending between a third divergence point located on the third loop between the eighth heat exchanger and the ninth heat exchanger and a fifth convergence point located on the first loop between the first junction point and the second heat exchanger.

[0020] The third loop is dedicated to the heat treatment of the vehicle's powertrain components. The eighth and tenth heat exchangers are used to heat the electric motor and the electrical storage device, respectively. The electric motor is likely to generate heat during operation, for example, when the vehicle is traveling at high speed, and requires cooling to regulate its temperature. The electrical storage device is also likely to generate heat, for example, after rapid recharging.

[0021] The ninth heat exchanger functions identically to the fifth heat exchanger, i.e., it cools the heat transfer fluid using the low-pressure refrigerant. The cooled heat transfer fluid in the ninth heat exchanger can then circulate to the eighth or tenth heat exchanger to provide heat to the electric motor or the electrical storage device, respectively, as required.

[0022] The fifth and sixth branches allow the first loop to be fluidly connected to the third loop. Such a fluid connection is particularly useful for connecting the second heat exchanger to the eighth heat exchanger in order to passively heat the electric motor by capturing its heat and dissipating it via the second heat exchanger using the outside airflow. In general, the branches that fluidly link the loops together increase the number of functionalities of the heat transfer fluid circuit according to the invention.

[0023] According to one feature of the invention, the heat transfer fluid circuit comprises a seventh branch extending between a fourth divergence point located on the third loop between the tenth heat exchanger and the fourth convergence point, and a sixth convergence point located on the third loop between the third divergence point 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 parallel to 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 can 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 it promotes the evaporation of the refrigerant as it subsequently circulates within the ninth heat exchanger. Advantageously, the electric heating element is used when no other heat source is available to perform an associated heat treatment function.

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

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

[0027] According to one feature of the invention, the heat transfer fluid circuit comprises a ninth branch extending between a sixth divergence point located on the first loop between the fourth heat exchanger and the first heat exchanger and an eighth convergence point located on the third loop between the fifth divergence point and the tenth heat exchanger, and a tenth branch extending between a seventh divergence point located on the third loop between the tenth heat exchanger and the seventh convergence point and a third junction point located on the fifth branch. The ninth and tenth branches allow the tenth heat exchanger to be fluidly linked to the third and fourth heat exchangers, so that the electrical storage device can be heated 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 one feature of the invention, the sixth divergence point includes a bypass element. This bypass element is, for example, a three-way valve allowing the heat transfer fluid to be directed to the first heat exchanger or to the ninth branch as required.

[0029] According to one feature of the invention, the first heat exchanger and the second heat exchanger are superimposed relative to each other along the direction of the outside airflow, the first heat exchanger being located downstream of the second heat exchanger with respect to said direction of the outside airflow. Such a configuration makes it possible to improve the compactness of the heat transfer fluid circuit, particularly the section arranged at the front of the vehicle, without compromising the thermal performance of the heat transfer fluid.

[0030] With respect to the direction of the outside airflow, the second heat exchanger is positioned 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 airflow thus increases in temperature as it passes through the second heat exchanger, but at a sufficiently low temperature to subsequently heat the heat transfer fluid circulating in the first heat exchanger effectively as it passes through it.

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

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

[0033] Following this, the refrigerant circuit divides into two paths, each of which includes an expansion valve. Downstream of these valves, one of these paths includes the fifth heat exchanger, while the other path includes the Ninth heat exchanger. Expansion valves are used to expand the refrigerant and reduce its pressure and temperature. The refrigerant is then evaporated within the fifth or eighth heat exchanger, simultaneously cooling the heat transfer fluid circulating within it. Depending on the operating mode, the refrigerant may 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 rejoin and the evaporated refrigerant is recompressed by the compression device. The refrigerant circuit may optionally include an accumulation device to retain a non-evaporated liquid fraction to prevent it from damaging the compression device as it passes through it. The refrigerant circuit may also include an internal heat exchanger that performs heat exchange between the high-pressure and low-pressure refrigerants to regulate the thermodynamic equilibrium of the refrigerant while improving the performance of the thermodynamic cycle of said refrigerant.

[0035] Other features and advantages of the invention will become apparent from the following description on the one hand, and from several illustrative and non-limiting examples of embodiments given by reference to the accompanying 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,

[0037] [Fig.2] represents a first mode of fluid circulation within said heat treatment system,

[0038] [Fig.3] represents a second mode of fluid circulation within said heat treatment system,

[0039] [Fig.4] represents a third mode of fluid circulation within said heat treatment system,

[0040] [Fig.5] represents a fourth mode of fluid circulation within said heat treatment system,

[0041] [Fig.6] represents a heat treatment system comprising a variant of the heat transfer fluid circuit according to the invention,

[0042] [Fig.7] represents a mode of fluid circulation within the heat treatment system comprising the variant of the heat transfer fluid circuit.

[0043] The terms "upstream" and "downstream" used in the following description refer to the direction of flow of the fluid in question, i.e. the refrigerant or the heat transfer fluid.

[0044] In Figures 1 and 6, a heat transfer fluid circuit 2 is shown with solid lines, and several sections of a refrigerant circuit 3 are shown with dashed lines. In Figures 2 to 5 and 7, for each circuit, the portions through which their respective fluid flows are shown with solid lines, and the portions without fluid circulation are shown with dashed lines. The solid lines indicating fluid circulation are also of different thicknesses for the refrigerant circuit 3 when it is in use. More specifically, the thickest solid lines correspond to portions where the refrigerant flows at high pressure, and the thinnest solid lines correspond to portions where the refrigerant flows at low pressure.

[0045] Figure 1 represents a heat treatment system 1 that can be integrated into a motor vehicle and includes 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 for the vehicle's passenger compartment, as well as heat treatment for various components of the vehicle's powertrain.

[0046] To achieve this, the heat treatment system comprises a heat transfer fluid circuit 2 through which a heat transfer fluid circulates, and a refrigerant fluid circuit 3 through which a refrigerant circulates. The heat treatment system 1 is configured to operate various interactions between the heat transfer fluid and the refrigerant in order to optimally heat the vehicle passenger compartment and the various components of the vehicle's powertrain. The heat transfer fluid can, for example, be glycol water, while the refrigerant can advantageously be an R290 type fluid, i.e., propane, which meets European environmental protection standards, unlike other types of refrigerants used for heat treatment.

[0047] The heat transfer fluid circuit 2 is divided into several fluidly connected sections in order to multiply the functionalities of the heat treatment system 1.

[0048] The heat transfer fluid circuit 2 includes 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.

[0049] The first pumping device 5 is used to circulate the heat transfer fluid. The first heat exchanger 6 and the second heat exchanger 7 are configured to exchange heat between the heat transfer fluid circulating within them and an outside airflow 10 passing through them. Outside airflow is defined as airflow not intended to be directed into the vehicle's passenger compartment. To be positioned along the path of the outside airflow 10, the first heat exchanger 6 and the second heat exchanger 7 can, for example, be arranged on the front of the vehicle.

[0050] In [Fig. 1] and the following figures, the first heat exchanger 6 and the second heat exchanger 7 are separated from each other for clarity of the figures, but advantageously, the first heat exchanger 6 and the second heat exchanger 7 are superimposed with respect to each other in a direction of the outside airflow so that an outside airflow 10 passes through the first heat exchanger 6 and the second heat exchanger 7 in series.

[0051] The third heat exchanger 8 and the fourth heat exchanger 9 are configured to operate a heat exchange between the heat transfer fluid circulating in them and the refrigerant circulating in the refrigerant circuit 3.

[0052] 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 and then in the fourth heat exchanger 9, while the refrigerant circulates in the fourth heat exchanger 9 and then in the third heat exchanger 8.

[0053] 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, heat is therefore transferred from the refrigerant to the heat transfer fluid. The heat exchange taking place in the first heat exchanger 6 and in the second heat exchanger 7 via the outside air flow 10 can, in particular, dissipate this heat absorbed by the heat transfer fluid.

[0054] The heat transfer fluid circuit 2 also includes a second loop 11 through which the heat transfer fluid can also circulate. The second loop 11 includes 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 allows the heat transfer fluid to be circulated.

[0055] The fifth heat exchanger 13 is configured to perform a heat exchange between the heat transfer fluid circulating in the second loop 11 and the refrigerant 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 13 is with the refrigerant at low pressure and low temperature, thus allowing the heat transfer fluid to be cooled.

[0056] The sixth heat exchanger 14 is configured to perform heat exchange between the heat transfer fluid and an internal airflow 15. Unlike the external airflow 10, the internal airflow 15 is intended to be sent to the vehicle's passenger compartment for thermal treatment. As such, the sixth heat exchanger 14 can be arranged within a ventilation, heating, and / or air conditioning system that allows the internal airflow 15 to be directed, in particular, through the sixth heat exchanger 14 before sending it to the vehicle's passenger compartment. Within the sixth heat exchanger 14, the heat transfer fluid absorbs heat from the interior airflow 15, and this air is then sent, cooled, to air-condition the vehicle's passenger compartment.

[0057] Within the heat transfer fluid circuit 2, the first loop 4 and the second loop 11 are fluidly connected to each other by a first branch 16 and a second branch 17. The first branch 16 begins at a first junction point 18 located 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 located 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 divergence point 20 located 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 convergence point 21 located 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 fluidic 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 thermal 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 located 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 link the first heat exchanger 6 to the fourth heat exchanger 9 by bypassing the second heat exchanger 7 and the third heat exchanger 8.

[0060] The heat transfer fluid circuit 2 also includes a fourth branch 24 extending between a second divergence point 25 located on the first loop 4 between the fourth heat exchanger 9 and the second convergence point 21, and a second junction point 26 located on the first loop 4 between the second heat exchanger 7 and the third heat exchanger 8. The fourth branch 24 includes a seventh heat exchanger 27 configured to perform heat exchange between the heat transfer fluid and the interior airflow 15. Like the sixth heat exchanger 14, the seventh heat exchanger 27 is advantageously located within the ventilation, heating, and / or air conditioning system mentioned above. As will be detailed later, the seventh heat exchanger 27 contributes to heating the vehicle's passenger compartment.

[0061] The heat transfer fluid circuit 2 also includes a third loop 28. This third loop 28 is dedicated to the thermal regulation of the components of a vehicle's powertrain. The third loop 28 includes 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 for the thermal 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 according to their respective temperatures.

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

[0064] The tenth heat exchanger 32 enables the thermal 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 according to their respective temperatures.

[0065] The first loop 4 and the third loop 28 are fluidly connected by a fifth branch 33 and a sixth branch 34. The fifth branch 33 extends between the second junction point 26 and a fourth convergence point 35 located 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 divergence point 36 located on the third loop 28 between the eighth heat exchanger 30 and the ninth heat exchanger 31 and a fifth convergence point 37 located 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 notably allow the fluidly connection of the second heat exchanger 7 and the eighth heat exchanger 30.

[0066] The heat transfer fluid circuit 2 includes a seventh branch 38 extending between a fourth divergence point 39 located on the third loop 28 between the tenth heat exchanger 32 and the fourth convergence point 35, and a sixth convergence point 40 located on the third loop 28 between the third divergence point 36 and the ninth heat exchanger 31. The seventh branch 38 also includes a fourth pumping device 41 and an electric heating element 42. The fourth pumping device 41 allows the heat transfer fluid to circulate in the seventh branch 38. The electric heating element 42 provides additional heating of the heat transfer fluid when required.

[0067] Finally, the heat transfer fluid circuit 2 includes an eighth branch 43 extending between a fifth divergence point 44 located on the third loop 28 between the ninth heat exchanger 31 and the tenth heat exchanger 32 and a seventh convergence point 45 located on the third loop 28 between the tenth heat exchanger 32 and the fourth divergence point 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 in 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 include a bypass element 46. Such a bypass element 46 may be in the form of a three-way valve for determining the flow of the heat transfer fluid. The heat transfer fluid circuit 2 may also include one or more check valves 47 that allow the heat transfer fluid to flow in one direction but prevent it in the opposite direction.

[0069] The refrigerant circuit 3 is only partially shown in the figures, but its essential elements are represented. The refrigerant circuit 3 comprises a main channel 48 equipped with a compression device 49, the third heat exchanger 8, and the fourth heat exchanger 9. The refrigerant circulating in the main channel 48 passes successively through the fourth heat exchanger 9 and then the third heat exchanger 8.

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

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

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

[0073] The refrigerant is then divided into two fractions. A first fraction circulates in the first channel 50 and a second fraction circulates in the second channel 51. The first fraction is expanded to low pressure by the first expansion valve 52 and then circulates within the fifth heat exchanger 13 to cool the heat transfer fluid circulating in the second loop 11. The latter is put into circulation 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 airflow 15 which is cooled and sent to the vehicle's passenger compartment to provide the air conditioning function.

[0074] The second fraction is expanded to low pressure by the second expansion valve 53 and circulates within the ninth heat exchanger 31 to cool the heat transfer fluid circulating in the third loop 28. This fluid is circulated by the fourth pumping device 41 and cooled within the ninth heat exchanger 31. The cooled heat transfer fluid then circulates within the tenth heat exchanger 32 to cool the electrical storage device. The latter is likely to release heat during its operation, for example after a rapid recharge. The cold heat transfer fluid thus captures the heat released by the electrical storage device. 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] For the refrigerant to expand and effectively cool the heat transfer fluid, condensation and possibly prior subcooling are essential. Therefore, 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, the heat transfer fluid also circulates in the first loop 4, being put into circulation 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 to condense by circulating in the third heat exchanger 8 and in the fourth heat exchanger 9. The heat transfer fluid then absorbs the heat from the refrigerant, and this heat is subsequently dissipated by the outside air flow 10 when the heat transfer fluid circulates in the first heat exchanger 6 and in the second heat exchanger 7. However, only part of the heat transfer fluid circulates in the second heat exchanger 7 and in the third heat exchanger 8. This allows for two-stage condensation or condensation followed by cooling (or "subcooling") of the refrigerant as it circulates within the fourth heat exchanger 9 and then the third heat exchanger 8 in order to improve the performance of the heat treatment system 1.

[0079] As previously mentioned, the first heat exchanger 6 and the second heat exchanger 7 are superimposed with respect to each other with respect to the direction of circulation of the outside air flow 10. The latter thus passes first through the second heat exchanger 7 and then through the first heat exchanger 6. The heat transfer fluid circulating within the second heat exchanger 7 being necessarily at a lower temperature than the heat transfer fluid circulating within the first heat exchanger 6, the outside air flow 10 thus rises in temperature as it passes through the second heat exchanger 7 but in a sufficiently small way to subsequently heat efficiently treat the heat transfer fluid circulating in the first heat exchanger 6 as it passes through the latter.

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

[0081] According to this second operating mode, the electric motor also requires cooling, as it is likely to generate heat during operation, for example, when the vehicle is traveling at moderate speed. The third pumping device 29 therefore circulates the heat transfer fluid, which then flows within the eighth heat exchanger 30 separately from the heat transfer fluid responsible for cooling the electrical storage device. The heat transfer fluid thus absorbs the heat generated by the electric motor and subsequently circulates in the sixth branch 34 via the third divergence point 36 in order to rejoin the first loop 4.

[0082] Having done this, the heat transfer fluid circulates within the second heat exchanger 7, joining the fraction of heat transfer fluid that thermally treats the refrigerant within the third heat exchanger 8. Thus, the calories captured from the electric motor by the heat transfer fluid are dissipated by the outside air flow 10.

[0083] At the outlet of the second heat exchanger 7, part of the heat transfer fluid circulates within the fifth branch 33 until it again joins the eighth heat exchanger 30 to cool the electric motor.

[0084] Figure 4 illustrates a third operating mode of the heat treatment system 1. The objective of this third operating mode is to dehumidify the vehicle's passenger compartment while passively cooling the electric motor. The dehumidification process consists of first cooling the interior airflow 15 via the sixth heat exchanger 14 to condense and retain the moisture contained in the interior airflow 15, and then reheating the interior airflow 15 using the seventh heat exchanger 27 to send warm, dry air into the vehicle's passenger compartment.

[0085] For this purpose, as described in [Fig.2], the heat transfer fluid circulates in the second loop 11 to be cooled by the refrigerant within the fifth heat exchanger 13 and subsequently cools the internal airflow 15 within the sixth heat exchanger 14.

[0086] In parallel, the heat transfer fluid is also circulated in the first loop 4 and heats up by condensing the refrigerant within at least the fourth heat exchanger 9. The hot refrigerant then separates into two fractions at the second divergence point 25. A first fraction circulates in the fourth branch 24 to the seventh heat exchanger 27 and transfers the heat captured in at least the fourth heat exchanger 9 to the indoor airflow 15. At the outlet of the seventh heat exchanger 27, the heat transfer fluid continues its circulation in the fourth branch 24 and rejoins the first loop 4 via the second junction point 26. The dehumidification function is thus implemented.

[0087] The second fraction circulates within the first heat exchanger 6 in which the calories are dissipated by the outside air flow 10. The entirety of said heat transfer fluid then circulates within the third branch 22 to reach the fourth heat exchanger 9.

[0088] Just as has been described for the second mode of operation, the electric motor is passively cooled by means of the fluidic connection, via the fifth branch 33 and the sixth branch 34, between the eighth heat exchanger 30 where the heat from the heat engine is captured by the heat transfer fluid and the second heat exchanger 7 where the heat captured by the heat transfer fluid is dissipated by the outside air flow 10.

[0089] 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 engine electric. 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 circulating in the main channel 48 and circulating in particular within the third heat exchanger 8.

[0090] It should be noted that, with regard to this third mode of operation, the refrigerant does not circulate in the second path 51 because it is not necessary to operate the ninth heat exchanger 31.

[0091] Figure 5 represents a fourth operating mode of the heat treatment system 1 according to the invention. This fourth operating mode allows the vehicle's passenger compartment to be heated and implements in parallel several means of improving the performance of the thermodynamic cycle of the refrigerant, particularly with regard to its evaporation.

[0092] Regarding the heating of the passenger compartment, the heat transfer fluid is heated by means of the high-temperature refrigerant and the heat exchange taking place in the third heat exchanger 8 and in the fourth heat exchanger 9. Then the refrigerant circulates in the fourth branch 24 to heat the interior airflow 15 by means of the seventh heat exchanger 27.

[0093] Heating the vehicle's passenger compartment 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 cases where no component requires cooling, as illustrated in [Fig. 5], another heat source must be used to promote the evaporation of the refrigerant.

[0094] At the level of the fifth heat exchanger 13, the heat transfer fluid circulates between the latter and the first heat exchanger 6 by means of the first branch 16 and the second branch 17. The heat transfer fluid is thus heated by the outside air flow 10 and then circulates within the fifth heat exchanger 13 to evaporate the refrigerant which circulates in the first channel 50.

[0095] The refrigerant is also evaporated within the ninth heat exchanger 31 by circulating in the second channel 51. To promote this evaporation, the heat transfer fluid can circulate within the eighth heat exchanger 30 to capture the heat released by the electric motor. The heat transfer fluid can also circulate within the seventh channel 38 to be heated by the electric heating element 42. The heat transfer fluid is thus at a sufficient temperature to transfer its heat to the refrigerant so that the latter evaporates during the heat exchange taking place in the ninth heat exchanger 31. Since the electrical storage device does not require treatment Thermally, 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 even though it does not need to be cooled, the heat transfer fluid can circulate in the heat exchanger 32 to recover this available heat.

[0096] Fig. 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 Fig. 1 for the characteristics common to the heat transfer fluid circuit 2 and its variant.

[0097] The variant illustrated in [Fig.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 divergence point 55 located on the first loop 4 between the fourth heat exchanger 9 and the first heat exchanger 6 and an eighth convergence point 56 located on the third loop 28 between the fifth divergence point 44 and the tenth heat exchanger 32, and a tenth branch 57 extending between a seventh divergence point 58 located on the third loop 28 between the tenth heat exchanger 32 and the seventh convergence point 45 and a third junction point 59 located on the fifth branch 33.

[0098] The ninth branch 54 and the tenth branch 57 allow the third heat exchanger 8 and the fourth heat exchanger 9 to be fluidly connected to the tenth heat exchanger 32. This allows the electrical storage device to be heated 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 indeed need to be heated, for example when starting the vehicle and / or in case of low ambient temperature.

[0099] The sixth divergence point 55 may also include 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 located 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, allowing the heat transfer fluid to be directed to the fourth branch 24 and / or to the ninth branch 54 and / or to the first heat exchanger 6.

[0100] 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 shown in Figure 5 but exploiting the specific structural and functional characteristics of the variant. Therefore, refer to the description in [Fig. 5] for the fluid flows common to both circulation modes.

[0101] In addition to heating the vehicle's passenger compartment and improving the performance of the thermodynamic cycle with heat input 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.

[0102] To this end, the heat transfer fluid circulating in the first loop is heated by circulating through the third heat exchanger 8 and the fourth heat exchanger 9. It is then sent partly to the fourth branch 24, as described previously, but also to the ninth branch 54. The heat transfer fluid then circulates to the tenth heat exchanger 32 to transfer its heat to the electrical storage device to heat it. From 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 from what was described previously is that the heat transfer fluid circulates in the fifth branch 33 in the opposite direction to that described in [Fig. 3] or 4, for example.The heat transfer fluid therefore flows 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.

[0103] Of course, the invention is not limited to the examples just described and many modifications can be made to these examples without departing from the scope of the invention.

[0104] The invention, as described above, achieves its intended purpose and provides a heat transfer fluid circuit that improves the thermal performance of the treatment system to which said heat transfer fluid circuit is connected. Variations not described here could be implemented without departing from the scope of the invention, provided that, in accordance with the invention, they include a heat transfer fluid circuit conforming to the invention.

Claims

1. Demands 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 perform a heat exchange between the heat transfer fluid and an outside airflow (10) to a vehicle passenger compartment, a third heat exchanger (8) and a fourth heat exchanger (9) both configured to perform 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 perform 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 perform heat exchange between the heat transfer fluid and an interior airflow (15) intended to be sent into the vehicle's passenger compartment, characterized in that the heat transfer fluid circuit (2) comprises a first branch (16) extending between a first junction point (18) located on the first loop (4) between the first heat exchanger (6) and the second heat exchanger (7) and a first convergence point (19) located 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 divergence point (20) located on the second loop (11) downstream of the fifth heat exchanger (13) and upstream of the sixth heat exchanger (14) and a second convergence point (21) located 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 convergence point (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 divergence point (25) disposed on the first loop (4) between the fourth heat exchanger (9) and the second convergence point (21) and a second junction point (26) disposed 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 operate a heat exchange between the heat transfer fluid and the internal airflow (15).

3. Heat transfer fluid circuit (2) according to claim 2, comprising a third loop (28) having 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 operate 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) located 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) located on the third loop (28) between the eighth heat exchanger (30) and the ninth heat exchanger (31) and a fifth convergence point (37) located 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 divergence point (39) disposed on the third loop (28) between the tenth heat exchanger (32) and the fourth convergence point (35) and a sixth convergence point (40) disposed on the third loop (28) between the third divergence point (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 divergence point (44) disposed on the third loop (28) between the ninth heat exchanger (31) and the tenth heat exchanger (32) and a seventh convergence point (45) disposed on the third loop (28) between the tenth heat exchanger (32) and the fourth divergence point (39).

6. Heat transfer fluid circuit (2) according to the preceding claim, wherein the first divergence point (20) and / or the second divergence point (25) and / or the third divergence point (36) and / or the fifth divergence point (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 divergence point (55) disposed on the first loop (4) between the fourth heat exchanger (9) and the first heat exchanger (6) and an eighth convergence point (56) disposed on the third loop (28) between the fifth divergence point (44) and the tenth heat exchanger (32), and a tenth branch (57) extending between a seventh divergence point (58) disposed on the third loop (28) between the tenth heat exchanger (32) and the seventh convergence point (45) and a third junction point (59) disposed on the fifth branch (33).

8. Heat transfer fluid circuit (2) according to the preceding claim, wherein the sixth divergence point (55) comprises a bypass element (46).

9. Heat transfer fluid circuit (2) according to any one of the preceding claims, wherein the first heat exchanger (6) and the second heat exchanger (7) are superimposed with respect to each other in a direction of circulation of the outside airflow (10), the first heat exchanger (6) being disposed downstream of the second heat exchanger (7) with respect to said direction of circulation of the outside airflow (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 coolant fluid circuit (3).

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