Method for controlling a thermal conditioning system for a motor vehicle

Abstract

The invention relates to a method for controlling a thermal conditioning system (100) for a motor vehicle, comprising a main loop (A) of refrigerant (10) successively comprising: -- a compressor (7), -- a first heat exchanger (1) thermally coupled with an interior airflow (Fi) to the passenger compartment, -- a first expansion valve (31), -- a second expansion valve (32), -- a second heat exchanger (2) configured to exchange heat with an exterior airflow (Fe), -- an accumulator (8), -- an internal heat exchanger (6) allowing heat exchange between the refrigerant circulating between the two expansion valves (31, 32), and the refrigerant returning to the compressor (7), the method comprising the steps: - circulating refrigerant at high pressure in the first heat exchanger (1), - expanding the refrigerant to an intermediate pressure and circulating it in the internal heat exchanger (6),- reduce the refrigerant pressure to a low level and circulate it through the second heat exchanger (2). See Figure 3 for an abstract.

Description

Title of the invention: Method for controlling a thermal conditioning system for a motor vehicle. Technical field

[0001] The present invention relates to the field of thermal conditioning systems. Such systems can, for example, be fitted to motor vehicles. These systems ensure thermal regulation of various vehicle components, such as the passenger compartment or an electrical energy storage battery, when the vehicle is electrically powered. Heat exchange is managed primarily by the compression and expansion of a refrigerant circulating in a circuit containing several heat exchangers. A compressor forces the refrigerant into a high-pressure state, allowing its circulation within the circuit. Previous technique

[0002] It is known to use carbon dioxide as a refrigerant, which makes it possible to limit to a minimum the global warming potential (GWP coefficient) of the refrigerant used.

[0003] Various thermal conditioning systems adapted to operate with carbon dioxide as a refrigerant have been proposed. These systems can perform many different functions, depending on the heat exchangers through which the refrigerant circulates and the expansion ratio provided by each of the expansion devices upstream of these exchangers. Possible operating modes include heating and cooling the vehicle cabin, as well as cooling and heating electrical energy storage batteries.

[0004] In order to further optimize such thermal conditioning systems, it is desirable to optimize the operating modes, as well as their control. Summary

[0005] To this end, a method for controlling a thermal conditioning system for a motor vehicle is proposed. The thermal conditioning system comprises a refrigerant circuit, the refrigerant circuit comprising: - A main loop comprising successively, according to the direction of refrigerant flow: — a compressor, — a first heat exchanger thermally coupled with an airflow from inside a vehicle passenger compartment, — a first regulator, — a second regulator, — a second heat exchanger configured to exchange heat with an outside airflow to the vehicle's passenger compartment, — a refrigerant fluid accumulation device. The main loop includes an internal exchanger configured to allow heat exchange between the refrigerant circulating between the first expansion valve and the second expansion valve, and the refrigerant downstream of the accumulation device and upstream of a compressor inlet. The proposed process involves the following successive steps: (i) provide a high-pressure refrigerant flow at the compressor outlet, (ii) circulate high-pressure refrigerant through the first heat exchanger, (iii) reduce the high-pressure refrigerant from the first heat exchanger to an intermediate pressure lower than the high pressure, (iv) circulate the intermediate-pressure refrigerant through the internal heat exchanger, (v) reduce the refrigerant fluid from the internal heat exchanger to a low pressure below the intermediate pressure, (vi) circulating the low-pressure refrigerant through the second heat exchanger.

[0006] The high-pressure refrigerant releases heat to the interior airflow at the first heat exchanger. The low-pressure refrigerant absorbs heat from the outside airflow at the second heat exchanger. The vehicle's interior can thus be heated by recovering energy from the outside airflow. After releasing heat to the interior airflow, the high-pressure refrigerant undergoes two successive expansions. After the first of the two expansions, the intermediate-pressure refrigerant exchanges heat with the low-pressure refrigerant from the second heat exchanger returning to the compressor. The efficiency of the internal heat exchanger can be controlled by adjusting the intermediate pressure.The inlet temperature of the refrigerant into the compressor can thus be adjusted, which also allows the outlet temperature of the compressor to be adjusted. This reduces the thermomechanical stresses experienced by the compressor components. Furthermore, limiting the discharge temperature at the compressor outlet also limits the refrigerant inlet temperature at the first heat exchanger. This reduces the temperature difference of the refrigerant between the inlet and outlet of the first heat exchanger. The temperature gradient of the internal airflow along The direction of refrigerant flow is thus reduced. Passenger comfort is improved, as the air blown into the passenger compartment can be at a more uniform temperature.

[0007] The features listed in the following paragraphs can be implemented independently of each other or in any technically possible combination:

[0008] The refrigerant circuit is configured to circulate a refrigerant.

[0009] The compressor changes the refrigerant fluid from a low-pressure state, at the compressor inlet, to a high-pressure state, at the compressor outlet.

[0010] According to the proposed process, the first exchanger operates as a refrigerant fluid cooler.

[0011] According to one embodiment, the first heat exchanger is configured to exchange heat with the airflow inside the vehicle's passenger compartment.

[0012] According to one embodiment, the first heat exchanger is configured to exchange heat with a heat transfer fluid circulating in a closed heat transfer fluid circuit, the heat transfer fluid circuit comprising a heat exchanger configured to exchange heat with the airflow inside the vehicle's passenger compartment.

[0013] According to the proposed process, the second exchanger operates as a refrigerant fluid evaporator.

[0014] According to other modes of operation, the second exchanger can operate selectively as a refrigerant fluid condenser or as a refrigerant fluid evaporator.

[0015] The internal exchanger includes a first heat exchange section arranged on the main loop between the first expansion valve and the second expansion valve, as well as a second heat exchange section arranged on the main loop downstream of the accumulator and upstream of the compressor inlet.

[0016] The first expansion valve is configured to expand the refrigerant fluid between an outlet of the first exchanger and an inlet of the first heat exchange section of the internal exchanger.

[0017] The second expansion valve is configured to expand the refrigerant fluid between an outlet of the first heat exchange section of the internal exchanger and an inlet of the second exchanger.

[0018] The refrigerant from the first heat exchange section of the internal heat exchanger is expanded to a low pressure by passing through the second expansion valve. The refrigerant, expanded to a low pressure, then enters an inlet of the second heat exchanger.

[0019] According to an example of implementation of the proposed control method, the refrigerant circuit comprises: - a first branch connecting a first connection point located on the main loop downstream of a compressor outlet and upstream of the first exchanger to a second connection point located on the main loop downstream of the second heat exchanger and upstream of the accumulation device, the first branch including a third expansion valve.

[0020] The refrigerant circuit further comprises: - a second branch connecting a third connection point located on the main loop between the first exchanger and the second expansion valve to a fourth connection point located on the main loop downstream of the second exchanger and upstream of the accumulation device, the second branch comprising successively a fourth expansion valve and a third heat exchanger thermally coupled with an element of an electric traction chain of a motor vehicle.

[0021] The refrigerant circuit further comprises: - a third branch connecting a fifth connection point arranged on the main loop between the second expansion valve and the first expansion valve to a sixth connection point arranged on the main loop between the second connection point and the fourth connection point, the third branch comprising successively a fifth expansion valve and a fourth heat exchanger configured to exchange heat with the indoor airflow.

[0022] The refrigerant circuit further comprises: - a fourth branch connecting a seventh connection point located on the second branch downstream of the third exchanger and upstream of the fourth connection point to an eighth connection point located on the main loop between the fifth connection point and the second regulator.

[0023] The second branch of the bypass may include a sixth regulator disposed between the seventh connection point and the fourth connection point.

[0024] According to an example of implementation of the proposed method, the third regulator is in the closed position.

[0025] According to an example of implementation of the proposed method, the fourth regulator is in the closed position.

[0026] According to an example of implementation of the proposed method, the fifth regulator is in the closed position.

[0027] According to an example of implementation of the proposed method, the sixth regulator is in the closed position.

[0028] According to an example of an implementation of the proposed method, in which the second branch branch includes a sixth pressure regulator disposed between the seventh connection point and the fourth connection point, - the third regulator, the fourth regulator, the fifth regulator and the sixth regulator are jointly in the closed position.

[0029] The first exchanger and the second exchanger are thus the only exchangers to participate in the heat exchanges.

[0030] Depending on the operating mode, the third heat exchanger allows the element of the vehicle's electric powertrain to be selectively cooled or heated. The element of the vehicle's electric powertrain can thus be maintained, or placed, within a preferred temperature range corresponding to the optimal operation of that element.

[0031] According to one embodiment, the element of the vehicle's electric drive chain includes an electrical energy storage battery.

[0032] Alternatively or in addition, the element of the vehicle's electric drive chain includes an electric vehicle traction motor.

[0033] Alternatively or in addition, the element of the vehicle's electric traction chain includes an electronic control unit for the vehicle's electric traction motor.

[0034] According to one embodiment, the third heat exchanger is thermally coupled with the element of the electric traction chain via a heat transfer fluid circulating in a heat transfer fluid circuit.

[0035] The fourth exchanger can operate as a refrigerant fluid evaporator.

[0036] The fifth expansion valve is configured to expand the refrigerant circulating between the main loop and an inlet of the fourth exchanger.

[0037] The fourth exchanger is arranged upstream of the first exchanger according to a direction of flow of the internal airflow.

[0038] Each regulator is, for example, an electronic regulator.

[0039] According to one aspect of the proposed control method, the method comprises the step: - receive a temperature setpoint for the indoor airflow exiting the first heat exchanger, - determine the temperature of the indoor airflow at the outlet of the first heat exchanger, - control a refrigerant flow rate in the refrigerant circuit so that the determined temperature of the indoor air flow at the outlet of the first exchanger is equal to the temperature setpoint.

[0040] According to one aspect of the control process, the process comprises the step: - control a compressor rotation speed in order to control the flow of refrigerant in the refrigerant circuit.

[0041] According to one embodiment, the control method includes the substep: - increasing the compressor rotation speed when the determined temperature of the indoor air flow at the outlet of the first exchanger is lower than the setpoint temperature.

[0042] Similarly, the control method may include the substep: - reducing the compressor rotation speed when the determined temperature of the indoor air flow at the outlet of the first exchanger is greater than the setpoint temperature.

[0043] According to another aspect of the proposed control method, the method includes the step: - determining a maximum allowable pressure of the refrigerant at the compressor outlet, - determining a pressure of the refrigerant at the compressor outlet, - controlling an expansion of the refrigerant in the second expansion valve so that the determined pressure of the refrigerant at the compressor outlet is less than the maximum allowable pressure.

[0044] The proposed control method may include the substep: - decrease a cross-section of the refrigerant passage through the second expansion valve if the determined pressure of the refrigerant at the compressor outlet is less than a target value.

[0045] The proposed control method may include the substep: - increase the refrigerant flow area through the second expansion valve if the determined refrigerant pressure at the compressor outlet is greater than a target value.

[0046] According to yet another aspect of the proposed control method, the method may comprise the following steps: - determine a maximum permissible temperature of the refrigerant at the compressor outlet, - determine a temperature of the refrigerant at the compressor outlet, - control an expansion of the refrigerant in the first expansion valve so that the determined temperature is lower than the maximum temperature.

[0047] The proposed control method may include the following step: - decrease a cross-section of the refrigerant flow through the first expansion valve if the determined temperature of the refrigerant at the compressor outlet is greater than a target value.

[0048] Similarly, the proposed control method may include the step: - increase the cross-sectional area of ​​the refrigerant passing through the first expansion valve if the determined temperature of the refrigerant at the compressor outlet is less than a target value.

[0049] A thermal conditioning system for motor vehicles is also proposed, comprising a refrigerant circuit including: - A main loop comprising successively, according to the direction of refrigerant flow: — a compressor, — a first heat exchanger thermally coupled with an airflow inside a vehicle's passenger compartment, — a first regulator, — a second regulator, — a second heat exchanger configured to exchange heat with an outside airflow to the vehicle's passenger compartment, — a refrigerant accumulation device, the main loop comprising an internal exchanger configured to allow heat exchange between the refrigerant circulating between the first and second expansion valves and the refrigerant downstream of the accumulation device and upstream of a compressor inlet, - an electronic control unit configured to implement the process as described above.

[0050] According to one embodiment, the refrigerant circuit further comprises: - a first branch connecting a first connection point located on the main loop downstream of a compressor outlet and upstream of the first heat exchanger to a second connection point located on the main loop downstream of the second heat exchanger and upstream of the accumulation device, the first branch comprising a third expansion valve, - a second branch connecting a third connection point located on the main loop between the first exchanger and the second expansion valve to a fourth connection point located on the main loop downstream of the second exchanger and upstream of the accumulation device, the second branch comprising successively a fourth expansion valve and a third heat exchanger thermally coupled with an element of an electric traction chain of a motor vehicle. - a third branch connecting a fifth connection point located on the main loop between the second regulator and the first regulator to a sixth connection point located on the main loop between the second connection point and the fourth connection point, the third branch a bypass branch comprising successively a fifth expansion valve and a fourth heat exchanger configured to exchange heat with the indoor airflow, - a fourth bypass branch E connecting a seventh connection point disposed on the second bypass branch downstream of the third exchanger and upstream of the fourth connection point to an eighth connection point disposed on the main loop between the fifth connection point and the second expansion valve.

[0051] The second branch includes a sixth regulator disposed between the seventh connection point and the fourth connection point.

[0052] According to one embodiment, the thermal conditioning system comprises: - A fifth branch connecting a ninth connection point located on the main loop downstream of the first connection point and upstream of the first exchanger to a tenth connection point located on the second branch downstream of the fourth expansion valve and upstream of the seventh connection point, the fourth branch comprising a seventh expansion valve.

[0053] The fifth bypass branch allows the high-pressure, high-temperature refrigerant from the compressor outlet to return to the compressor inlet without passing through the first or second heat exchangers. The fifth bypass branch returns the high-pressure refrigerant to the accumulator inlet, with the third heat exchanger being the only heat exchanger it passes through. The flow rate in the fifth bypass branch increases the total refrigerant flow rate supplied by the compressor, thus increasing the heating capacity provided by the refrigerant.

[0054] The refrigerant circuit includes a first one-way valve disposed on the main loop between the first exchanger and the third connection point.

[0055] The first one-way valve is configured to allow refrigerant flow from the first heat exchanger to the third connection point. The first one-way valve is also configured to prevent refrigerant flow from the third connection point to the first heat exchanger.

[0056] The refrigerant circuit includes a second one-way valve disposed on the fourth branch.

[0057] The second one-way valve being configured to allow refrigerant flow from the seventh connection point to the eighth connection point and configured to prohibit refrigerant flow from the eighth connection point to the seventh connection point. The refrigerant circuit includes a third one-way valve located on the main loop between the fourth exchanger and the sixth connection point.

[0058] The third one-way valve is configured to allow refrigerant flow from the fourth heat exchanger to the sixth connection point. The third one-way valve is also configured to prevent refrigerant flow from the sixth connection point to the fourth heat exchanger.

[0059] The first one-way valve is, for example, a check valve. Similarly, the second one-way valve and the third one-way valve can be a check valve.

[0060] The main loop includes a first shut-off valve disposed between the first connection point and the first heat exchanger.

[0061] The main loop includes a second shut-off valve disposed between the second connection point and the sixth connection point.

[0062] The first shut-off valve is an electrically operated valve. Similarly, the second shut-off valve is an electrically operated valve. Brief description of the drawings

[0063] Other features, details and advantages will become apparent upon reading the detailed description below, and upon analysis of the accompanying drawings, on which:

[0064] [Fig-1] is a schematic view of a thermal conditioning system according to a first embodiment of the invention,

[0065] [Fig.2] is a schematic view of a thermal conditioning system according to a second embodiment of the invention,

[0066] [Fig.3] is a schematic view illustrating the operation of the system of thermal conditioning of [Fig.2], when the proposed process is implemented,

[0067] [Fig.4] is a block diagram of the proposed process. Description of the implementation methods

[0068] To facilitate reading the figures, the various elements are not necessarily drawn to scale. In these figures, identical elements bear the same reference numerals. Certain elements or parameters may be indexed, that is, designated, for example, as first element or second element, or first parameter and second parameter, etc. This indexing aims to differentiate similar, but not identical, elements or parameters. This indexing does not imply any priority of one element or parameter over another, and the designations may be interchanged.

[0069] In the following description, the expression "a first element upstream of a second element" means that the first element is placed before the second An element is defined in relation to the direction of flow, or path, of a fluid. Similarly, the term "a first element downstream of a second element" means that the first element is located after the second element in relation to the direction of flow, or path, of the fluid in question. In the case of a refrigerant circuit, the term "a first element upstream of a second element" means that the refrigerant flows successively through the first element, then the second element, without passing through the compression device. In other words, the refrigerant exits the compression device, possibly passes through one or more elements, then passes through the first element, then the second element, and then returns to the compression device, possibly after passing through other elements.

[0070] The expression "a second element is placed between a first element and a third element" means that the shortest path to go from the first element to the third element or from the third element to the first element passes through the second element.

[0071] When it is specified that a subsystem includes a given element, this does not exclude the presence of other elements in that subsystem.

[0072] The thermal conditioning system 100, which will be described below, comprises an electronic control unit 61 that receives information from various sensors measuring, in particular, the characteristics of the refrigerant at various points in the circuit. The electronic control unit 61 also receives instructions from the vehicle occupants, such as the desired temperature inside the passenger compartment. The electronic control unit 61 can also receive instructions from other electronic subsystems, such as the electrical energy storage battery management system. The electronic control unit 61 implements control laws to operate the various actuators in order to control the thermal conditioning system 100 and ensure compliance with the received instructions. Control unit 61 can execute software coding the proposed process.

[0073] A compression device 7, also called a compressor, allows a refrigerant to circulate in a refrigerant circulation circuit 10. The compression device 7 can be an electric compressor, that is, a compressor whose moving parts are driven by an electric motor. The compression device 7 has a low-pressure refrigerant intake side, also called the inlet 7a of the compression device, and a high-pressure refrigerant discharge side, also called the outlet 7b of the compression device 7. The internal moving parts of the compressor 7 cause the refrigerant to go from a low pressure at the inlet 7a to a high pressure at the outlet 7b. After expansion in one or more expansion and circulation devices in at least part of the circuit, the refrigerant returns to the inlet 7a of the compressor 7 and begins a new thermodynamic cycle.

[0074] The refrigerant circuit 10 forms a closed circuit in which the refrigerant can circulate. The refrigerant circuit 10 is leak-proof when it is in a nominal operating state, that is, without any fault or leak. Each connection point of circuit 10 allows the refrigerant to flow into one of the circuit sections that converge at that point. The refrigerant is distributed between these sections by opening or closing the shut-off valves, check valves, or expansion devices located on each section. In other words, each connection point redirects the refrigerant arriving at that point. Various shut-off valves and check valves thus allow the refrigerant to be selectively directed into the different branches of the refrigerant circuit, in order to provide different operating modes, as will be described later.

[0075] The refrigerant used by the refrigerant circuit 10 is here a natural fluid, such as R744. It is also possible to use a chemical refrigerant, such as R1234yf, or R 134a.

[0076] Each refrigerant expansion device, also called an expansion valve, can be an electronic expansion valve. In an electronic expansion valve, the passage area through which the refrigerant flows can be continuously adjusted between a closed position and a maximum open position. To achieve this, an electronic control module drives an electric motor that moves a movable shutter, thus controlling the passage area available to the refrigerant. In the closed position, the circulation of refrigerant is interrupted; that is, the flow of refrigerant through the electronic expansion valve is zero. In the maximum open position, the refrigerant flows through the expansion valve without undergoing any expansion.

[0077] The term "interior airflow Fi" refers to an airflow directed towards the passenger compartment of the motor vehicle. This interior airflow Fi may circulate within a heating, ventilation, and / or air conditioning (HVAC) system. This system is not shown in the various figures. A first motor-fan unit, not shown, is located within the HVAC system to increase the flow rate of the interior airflow Fi if necessary.

[0078] The term "external airflow Fe" refers to an airflow that is not destined for the vehicle's passenger compartment. In other words, this airflow Fe remains outside the passenger compartment. of the vehicle. A second motor-fan unit, also not shown, can be activated to increase the flow rate of the outside airflow Fe if necessary. The airflow provided by the first as well as by the second motor-fan unit can be adjusted in real time according to the heat exchange requirements, for example by the electronic control unit 61 of the thermal conditioning system 100.

[0079] The term "first exchanger" is equivalent to the term "first heat exchanger". Similarly, the term "internal exchanger" is equivalent to the term "internal heat exchanger". The term "storage device" is equivalent to the term "refrigerant storage device".

[0080] The thermal conditioning system 100 may include one or more heat transfer fluid circuits. These heat transfer fluid circuits also form one or more closed and sealed circuits in which a heat transfer fluid can circulate.

[0081] Figure [Fig.1] shows a thermal conditioning system 100 for a motor vehicle, according to a first embodiment. The thermal conditioning system 100 includes a refrigerant fluid circuit 10. The refrigerant circuit 10 comprises a main loop A consisting successively, according to the direction of refrigerant flow: — a 7-inch compressor, — a first heat exchanger 1 thermally coupled with an internal airflow Fi to a vehicle passenger compartment, — a first regulator 31, — a second regulator 32, — a second heat exchanger 2 configured to exchange heat with an outside airflow Fe to the vehicle's passenger compartment, — a refrigerant fluid accumulation device 8. The main loop A includes an internal exchanger 6 configured to allow heat exchange between the refrigerant circulating between the first expansion valve 31 and the second expansion valve 32 and the refrigerant downstream of the accumulation device 8 and upstream of an inlet 7a of the compressor 7, The thermal conditioning system 100 includes an electronic control unit 61 configured to implement the process which will be described in detail below.

[0082] The refrigerant fluid circuit 10 is configured to circulate a refrigerant fluid. The compressor 7 changes the refrigerant fluid from a low pressure state, at the inlet 7a of the compressor 7, to a high pressure state, at the outlet 7b of the compressor 7.

[0083] The accumulation device 8, also called an accumulator, forms a storage volume for liquid refrigerant. The accumulation device 8 compensates for variations in the quantity of refrigerant circulating in the circuit 10, depending on operating conditions. The accumulation device 8 also separates the liquid and gaseous phases of the refrigerant so as to supply the compressor 7 with refrigerant in gaseous form.

[0084] The thermal coupling between the first heat exchanger 1 and the internal airflow Fi can be ensured in different ways.

[0085] According to the illustrated example, the first heat exchanger 1 is configured to exchange heat with the interior airflow Fi to the vehicle's passenger compartment.

[0086] The thermal coupling between the first heat exchanger 1 and the internal airflow Fi is said to be direct. Indeed, the internal airflow Fi is in contact with the walls of the heat exchanger 1 in which the refrigerant circulates. In this embodiment, the first heat exchanger 1 is located in the vehicle's heating, ventilation and / or air conditioning system.

[0087] According to an alternative embodiment not shown, the first heat exchanger 1 is configured to exchange heat with a heat transfer fluid circulating in a closed heat transfer fluid circuit. The closed heat transfer fluid circuit includes a heat exchanger configured to exchange heat with the interior airflow Fi to the vehicle's passenger compartment.

[0088] The thermal coupling between the first heat exchanger 1 and the interior airflow Fi is in this case said to be indirect, since it is achieved through a heat transfer fluid which transfers the heat supplied by the refrigerant fluid to the airflow Fi supplying the passenger compartment of the vehicle. The heat transfer fluid circulating in the circuit is, for example, a mixture of water and glycol. According to this variant, the heat exchanger of the heat transfer fluid circuit, also called a heater core, is located in the vehicle's heating, ventilation and / or air conditioning system.

[0089] The second exchanger 2 is for example located in the front face of the vehicle, in order to directly receive the outside airflow Fe. The second interchange 2, for example, is located behind the vehicle's grille.

[0090] The internal exchanger 6 includes a first heat exchange section 6a arranged on the main loop A between the first expansion valve 31 and the second expansion valve 32, and a second heat exchange section 6b arranged on the main loop A downstream of the accumulator 8 and upstream of the inlet 7a of the compressor 7. The internal exchanger 6, also called the internal heat exchanger, is configured to allow heat exchange between the refrigerant in the first heat exchange section 6a and the refrigerant in the second heat exchange section 6b.

[0091] Figure 2 illustrates a second embodiment of the thermal conditioning system 100. This embodiment differs from the first embodiment by the presence of additional elements.

[0092] The refrigerant circuit 10 further comprises a first branch B connecting a first connection point 11 located on the main loop A downstream of an outlet 7b of the compressor 7 and upstream of the first heat exchanger 1 to a second connection point 12 located on the main loop A downstream of the second heat exchanger 2 and upstream of the storage device 8, the first branch B comprising a third expansion valve 33. The refrigerant circuit 10 further includes a second branch C connecting a third connection point 13 located on the main loop A between the first heat exchanger 1 and the second expansion valve 32 to a fourth connection point 14 located on the main loop A downstream of the second heat exchanger 2 and upstream of the storage device 8, the second branch C comprising successively a fourth expansion valve 34 and a third heat exchanger 3 thermally coupled with an element 25 of an electric traction chain of a motor vehicle. The refrigerant circuit 10 further includes a third branch D connecting a fifth connection point 15 located on the main loop A between the second expansion valve 32 and the first expansion valve 31 to a sixth connection point 16 located on the main loop A between the second connection point 12 and the fourth connection point 14, the third branch D comprising successively a fifth expansion valve 35 and a fourth heat exchanger 4 configured to exchange heat with the internal airflow Fi. The refrigerant circuit 10 further includes a fourth branch E connecting a seventh connection point 17 located on the second branch C downstream of the third heat exchanger 3 and upstream of the fourth connection point 14 to an eighth connection point 18 located on the main loop A between the fifth connection point 15 and the second expansion valve 32.

[0093] The fourth heat exchanger 4 is located in the vehicle's heating, ventilation and / or air conditioning system. The fourth exchanger 4 is positioned upstream of the first exchanger 1 according to a direction of flow of the internal air flow Fi.

[0094] The second branch C includes a sixth regulator 36 disposed between the seventh connection point 17 and the fourth connection point 14.

[0095] The refrigerant circuit 10 includes several one-way valves and shut-off valves, in order to selectively circulate the refrigerant in various parts of the circuit, depending on the desired operating mode for the thermal conditioning system 100.

[0096] The refrigerant fluid circuit 10 includes a first one-way valve 43 disposed on the main loop A between the first exchanger 1 and the third connection point 13. The first one-way valve 43 is configured to allow refrigerant flow from the first heat exchanger 1 to the third connection point 13. The first one-way valve 43 is also configured to prohibit refrigerant flow from the third connection point 13 to the first heat exchanger 1.

[0097] The refrigerant fluid circuit 10 includes a second one-way valve 44 arranged on the fourth branch E. The second one-way valve 44 is configured to allow refrigerant flow from the seventh connection point 17 to the eighth connection point 18 and configured to prohibit refrigerant flow from the eighth connection point 18 to the seventh connection point 17.

[0098] The refrigerant fluid circuit 10 includes a third one-way valve 45 disposed on the main loop A between the fourth exchanger 4 and the sixth connection point 16. The third one-way valve 45 is configured to allow refrigerant flow from the fourth heat exchanger 4 to the sixth connection point 16. The third one-way valve 45 is also configured to prohibit refrigerant flow from the sixth connection point 16 to the fourth heat exchanger 4.

[0099] The first one-way valve 43 is, for example, a check valve. Similarly, the second one-way valve 44 and the third one-way valve 45 can be a check valve. A check valve is a passive device that reacts to the pressure difference between its inlet and outlet. No electrical control is required.

[0100] The main loop A includes a first shut-off valve 41 disposed between the first connection point 11 and the first heat exchanger 1. The first shut-off valve 41 is, for example, a two-way valve. The first shut-off valve 41 is located between the first connection point 11 and the ninth connection point 19. Alternatively, the first shut-off valve 41 can be an electronic expansion valve having a closed position, i.e. a position in which the flow of refrigerant through the expansion valve is zero.

[0101] The main loop A includes a second shut-off valve 42 disposed between the second connection point 12 and the sixth connection point 16. The second shut-off valve 42 is a two-way valve. The second shut-off valve 42 is located between the second connection point 12 and the sixth connection point 16.

[0102] The first shut-off valve 41 is an electrically operated valve. Similarly, the second shut-off valve 42 is an electrically operated valve.

[0103] Depending on the operating mode, the third heat exchanger 3 allows the element 25 of the vehicle's electric powertrain to be selectively cooled or heated. The element 25 of the vehicle's electric powertrain can thus be maintained, or placed, within a preferred temperature range corresponding to the optimal operation of that element.

[0104] According to one embodiment, element 25 of the vehicle's electric drive chain includes an electrical energy storage battery. Alternatively or in addition, element 25 of the vehicle's electric drive chain includes an electric vehicle traction motor. Alternatively or in addition, element 25 of the vehicle's electric drive chain includes an electronic control unit for the vehicle's electric traction motor.

[0105] According to the illustrated example, the third heat exchanger 3 is thermally coupled with the element 25 of the electric traction chain via a heat transfer fluid circulating in a heat transfer fluid circuit 40.

[0106] The heat transfer fluid circulating in the heat transfer fluid circuit 40 can exchange heat on the one hand with the refrigerant circulating in the third heat exchanger 3 and on the other hand with the element 25 of the vehicle's electric powertrain. The heat transfer fluid thus enables heat transfer between the refrigerant and the element 25 of the electric powertrain. For example, the heat transfer fluid circulates between the battery elements, or inside the wall of the electric motor casing. The heat transfer fluid circulating in circuit 40 is, for example, a mixture of water and glycol.

[0107] In this second embodiment, the thermal conditioning system 100 further comprises a fifth branch F connecting a ninth connection point 19 located on the main loop A downstream of the first connection point 11 and upstream of the first heat exchanger 1 to a tenth connection point 20 located on the second branch C downstream of the fourth expansion valve 34 and upstream of the seventh connection point 17. The fourth branch E comprises a seventh expansion valve 37.

[0108] The fifth bypass branch F allows the high-pressure, high-temperature refrigerant fluid exiting the compressor 7 to return to the compressor inlet 7 without passing through the first heat exchanger 1 or the second heat exchanger 2. The fifth bypass branch F forms a refrigerant passage that returns the high-pressure refrigerant fluid to the inlet of the accumulator 8, the third heat exchanger 3 being the only heat exchanger traversed between the outlet 7b of the compressor 7 and the inlet 7a of the compressor 7. The flow circulating in the fifth bypass branch F increases the total flow rate of refrigerant fluid supplied by the compressor 7 and thus increases the heating power supplied by the refrigerant.

[0109] Each regulator 31, ..., 37 is for example an electronic regulator.

[0110] The first branch of derivation B, the second branch of derivation C, and the third branch of derivation D are independent elements. Thus, according to unrepresented variants, only one of these three elements may be present. Similarly, two of these elements may be present. In the example shown, all three elements are present together. Furthermore, the fourth branch E may or may not be present when the second branch C is present. Similarly, the fifth branch F may or may not be present when the second branch C is present.

[0111] The thermal conditioning system 100 can operate in several modes. The proposed method, when implemented, corresponds to a particular operating mode of the thermal conditioning system 100.

[0112] A method for controlling a thermal conditioning system for a motor vehicle is thus proposed. The thermal conditioning system 100 comprises a refrigerant circuit 10, the refrigerant circuit 10 comprising: - a main loop A comprising successively, according to the direction of refrigerant flow: — a 7-inch compressor, — a first heat exchanger 1 thermally coupled with an internal airflow Fi to a vehicle passenger compartment, — a first expansion valve 31, — a second expansion valve 32, — a second heat exchanger 2 configured to exchange heat with an outside airflow Fe to the vehicle passenger compartment, — a refrigerant fluid storage device 8, the main loop A comprising an internal heat exchanger 6 configured to allow heat exchange between the refrigerant circulating between the first expansion valve 31 and the second expansion valve 32 and the refrigerant downstream of the storage device 8 and upstream of an inlet 7a of the compressor 7, the process comprising the successive steps: (i) provide a high-pressure refrigerant flow at the outlet of compressor 7, (ii) circulate high-pressure refrigerant through the first heat exchanger 1, (iii) reduce the high-pressure refrigerant from the first heat exchanger 1 to an intermediate pressure lower than the high pressure, (iv) circulate the intermediate-pressure refrigerant fluid through the internal heat exchanger 6, (v) reduce the refrigerant fluid from the internal heat exchanger 6 to a low pressure below the intermediate pressure, (vi) circulating the low-pressure refrigerant through the second heat exchanger 2.

[0113] The refrigerant releases heat to the interior airflow Fi at the first heat exchanger 1 and absorbs heat from the exterior airflow at the second heat exchanger 2. The vehicle's passenger compartment can thus be heated by recovering energy from the exterior airflow. After releasing heat to the interior airflow Fi, the high-pressure refrigerant undergoes two successive expansions, first in the first expansion valve 31 and then in the second expansion valve 32. After the first of the two expansions, the intermediate-pressure refrigerant exchanges heat in the internal heat exchanger 6 with the low-pressure refrigerant coming from the second heat exchanger 2 and returning to the inlet 7a of the compressor 7.The efficiency of the internal heat exchanger 6 can be controlled by adjusting the intermediate pressure value, by modifying the refrigerant flow area in the first expansion valve 31. The refrigerant inlet temperature in the compressor 7 can thus be adjusted, which also allows adjustment of the discharge temperature at the compressor outlet 7. The thermomechanical stresses experienced by the compressor components are therefore reduced, thus preventing premature degradation of the compressor 7 under the most severe conditions. Furthermore, limiting the discharge temperature at the compressor outlet 7 also limits the refrigerant inlet temperature at the first heat exchanger 1. This reduces the temperature difference of the refrigerant between the inlet 1a and the outlet 1b of the first heat exchanger 1. Consequently, the temperature gradient of the interior airflow Fi along the refrigerant flow direction is reduced. Passenger comfort is improved because the air supplied to the passenger compartment can be at a more uniform temperature. Indeed, since the refrigerant is cooler near outlet 1b than near inlet 1a, the portion of the interior airflow Fi passing through the first heat exchanger 1 in an area close to inlet 1a emerges at a higher temperature than the portion of the interior airflow passing through the first heat exchanger 1 in an area close to outlet 1b.This temperature gradient in the airflow Fi exiting the first heat exchanger 1 is particularly pronounced when the refrigerant is in a supercritical state. The temperature gradient also exists when the refrigerant is in a two-phase state, due to the desuperheating phenomenon in the first heat exchanger 1, and due to subcooling when operating conditions allow for subcooling.

[0114] According to the proposed process, the first exchanger 1 operates as a refrigerant fluid cooler. According to the proposed process, the second exchanger 2 operates as a refrigerant fluid evaporator. According to other operating modes, not illustrated, the second exchanger 2 can operate selectively as a refrigerant fluid condenser or as a refrigerant fluid evaporator.

[0115] The fourth heat exchanger 4 can operate as a refrigerant evaporator. The fifth expansion valve 35 is configured to expand the refrigerant circulating between the main loop A and an inlet of the fourth heat exchanger 4.

[0116] The fourth exchanger 4 is arranged upstream of the first exchanger 1 according to a direction of flow of the internal air flow Fi. The fourth heat exchanger 4 cools the indoor airflow Fi, and the first heat exchanger 1 heats the indoor airflow Fi. The indoor airflow can thus be dehumidified in certain operating modes.

[0117] The first expansion valve 31 is configured to expand the refrigerant fluid between an outlet of the first exchanger 1 and an inlet of the first heat exchange section 6a of the internal exchanger 6. The refrigerant from the first exchanger 1 is expanded to an intermediate pressure by passing through the first expansion valve 31. The refrigerant expanded to an intermediate pressure joins an inlet of the first heat exchange section 6a of the internal exchanger 6.

[0118] The second expansion valve 32 is configured to expand the refrigerant fluid between an outlet of the first heat exchange section 6a of the internal exchanger 6 and an inlet of the second exchanger 2. The refrigerant from the first heat exchange section 6a of the internal exchanger 6 is expanded to a low pressure by passing through the second expansion valve 32. The refrigerant expanded to a low pressure then enters an inlet of the second exchanger 2.

[0119] Figure 3 illustrates the circulation of the refrigerant in the circuit 10 when the proposed process is implemented on a thermal conditioning system 100 according to the second embodiment, the architecture of which is illustrated in Figure 2. The portions of the circuit 10 in which a flow of refrigerant circulates are shown in thick solid lines, while the portions in which the refrigerant does not circulate are shown in thin dashed lines.

[0120] A method for controlling a thermal conditioning system 100 is thus proposed, in which the refrigerant circuit 10 comprises: - a first branch branch B connecting a first connection point 11 located on the main loop A downstream of an outlet 7b of the compressor 7 and upstream of the first exchanger 1 to a second connection point 12 located on the main loop A downstream of the second heat exchanger 2 and upstream of the accumulation device 8, the first branch branch B comprising a third expansion valve 33, - a second branch C connecting a third connection point 13 located on the main loop A between the first exchanger 1 and the second expansion valve 32 to a fourth connection point 14 located on the main loop A downstream of the second exchanger 2 and upstream of the accumulation device 8, the second branch C comprising successively a fourth expansion valve 34 and a third heat exchanger 3 thermally coupled with an element 25 of an electric traction chain of a motor vehicle, - a third branch branch D connecting a fifth connection point 15 arranged on the main loop A between the second expansion valve 32 and the first expansion valve 31 to a sixth connection point 16 arranged on the main loop A between the second connection point 12 and the fourth connection point 14, the third branch branch D comprising successively a fifth expansion valve 35 and a fourth heat exchanger 4 configured to exchange heat with the internal airflow Fi, - a fourth branch E connecting a seventh connection point 17 located on the second branch C downstream of the third interchange 3 and upstream of the fourth connection point 14 to an eighth connection point 18 arranged on the main loop A between the fifth connection point 15 and the second regulator 32, in which the second branch C comprises a sixth regulator 36 disposed between the seventh connection point 17 and the fourth connection point 14, and in which: - the third regulator 33, the fourth regulator 34, the fifth regulator 35 and the sixth regulator 36 are jointly in the closed position.

[0121] The third regulator 33 is in the closed position. Thus, the entire flow of refrigerant fluid passing through the first exchanger 1 also passes through the third exchanger 3. The first branch of bypass B is not traversed by the refrigerant fluid.

[0122] The fourth regulator 34 is in the closed position. Thus, the third heat exchanger 3 does not participate in heat exchange.

[0123] The fifth expansion valve 35 is in the closed position. Thus, the fourth heat exchanger 4 does not participate in heat exchange.

[0124] According to the illustrated example, the sixth expansion valve 36 is in the closed position. Thus, the entire flow of refrigerant passing through the second heat exchanger 2 reaches the accumulator 8 without being redirected to the fourth branch E.

[0125] The second branch C does not carry the refrigerant.

[0126] The value of the so-called "high pressure" at the outlet of the compressor 7 is, for example, between 50 bar and 120 bar. The value of the so-called "intermediate" pressure, after expansion by the first pressure regulator 31, is lower than the value of the high pressure. The intermediate pressure is, for example, between 30 bar and 70 bar. The value of the so-called "low pressure", after expansion by the second regulator 32, is less than the value of the intermediate pressure. Low pressure, for example, is between 10 bars and 35 bars.

[0127] A flow Q of high-pressure refrigerant is supplied by the compressor 7. The high-pressure refrigerant reaches the first connection point 11. The first shut-off valve 41 is in the open position, and the third expansion valve 33 is in the closed position. The entire flow Q of refrigerant therefore circulates in the main loop A, passes through the first shut-off valve 41, and travels through the first heat exchanger 1, transferring heat to the indoor airflow Fi. The first expansion valve 31 is in the partially open position and the fourth expansion valve 34 is in the closed position. At the third connection point 13, the high-pressure refrigerant flows through the main loop A, undergoes expansion in the first expansion valve 31 to an intermediate pressure, and then reaches the fifth connection point 15. The fifth expansion valve 35 is in the closed position, therefore the third branch of the bypass D is not traversed by refrigerant fluid. The seventh expansion valve 37 is in the closed position, and the fifth branch of the bypass F is not traversed by refrigerant fluid. The second expansion valve 32 is in a partially open position. The intermediate-pressure refrigerant thus flows through the first heat exchange section 6a of the internal heat exchanger 6, then undergoes expansion in the second expansion valve 32 and drops to low pressure. The refrigerant evaporates in the second heat exchanger 2, absorbing heat from the outside airflow Fe. The second shut-off valve 42 is in the open position. The low-pressure refrigerant from the second heat exchanger 2 reaches the sixth connection point 16, then circulates through the storage device 8, the second heat exchange section 6b of the internal heat exchanger 6, and returns to the inlet 7a of the compressor 7, thus completing the thermodynamic cycle. The first heat exchange section 6a of the internal exchanger 6 is traversed by refrigerant fluid at intermediate pressure and the second heat exchange section 6b is traversed by refrigerant fluid at low pressure. For identical high-pressure and low-pressure values, the intermediate pressure can be adjusted by controlling the distribution between the expansion rate provided by the first expansion valve 31 and the expansion rate provided by the second expansion valve 32. The temperature of the refrigerant circulating in the second heat exchange section 6b can thus be controlled, which in turn allows control of the efficiency of the internal heat exchanger 6. Controlling the efficiency of the internal heat exchanger 6 allows control of the inlet temperature of the compressor 7 and therefore the outlet temperature of the compressor 7.

[0128] According to one aspect of the proposed process, the temperature of the internal airflow Fi at the outlet of the first exchanger 1 is controlled by acting on the flow rate of refrigerant fluid discharged by the compressor 7.

[0129] The proposed control method thus comprises the following steps: - receive a temperature setpoint Tc_l of the indoor airflow Fi at the outlet of the first exchanger 1, - determine a temperature Tl of the indoor airflow Fi at the outlet of the first exchanger 1, - control a refrigerant flow in the refrigerant circuit 10 so that the determined temperature Tl of the indoor air flow Fi at the outlet of the first exchanger 1 is equal to the temperature setpoint Tc_l.

[0130] The temperature of an airflow exiting a heat exchanger means the temperature of that airflow after having carried out a heat exchange with the refrigerant circulating in that heat exchanger.

[0131] The temperature Tl of the indoor airflow Fi at the outlet of the first exchanger 1 can for example be determined by a measuring sensor placed in the indoor airflow Fi, near the first exchanger 1 and downstream of it in a direction of flow of the indoor airflow Fi. According to alternative embodiments, the temperature Tl of the indoor airflow Fi at the outlet of the first exchanger 1 can be determined from a temperature measurement taken at another point in the passage of the indoor airflow Fi and from a model of temperature evolution between the point where the measurement is taken and the outlet of the first exchanger 1 for the indoor airflow Fi. The temperature measurement sensor was not shown in the figures.

[0132] According to one aspect of the control process, the process comprises the step: - control a compressor rotation speed 7 in order to control the flow of refrigerant in the refrigerant circuit 10.

[0133] In the case of an electric compressor, the rotation speed of the compressor is controlled by modulating the electric current supplied to the electric motor of the compressor 7.

[0134] Increasing the rotation speed of the compressor 7 increases the flow rate of refrigerant circulating in the compressor 7 and therefore in the circuit 10. Conversely, reducing the rotation speed of compressor 7 reduces the flow of refrigerant circulating in circuit 10.

[0135] The control process comprises the substep: - increase the compressor rotation speed 7 when the determined temperature Tl of the indoor airflow Fi is lower than the setpoint temperature Tc_l. By increasing the compressor speed 7, the refrigerant flow rate increases, as does the thermal power supplied to the first heat exchanger 1, which acts as a refrigerant cooler. The temperature of the indoor airflow Fi, after heat exchange with the refrigerant at the first heat exchanger 1, tends to approach its setpoint value Tc_l.

[0136] Similarly, the control method comprises the substep: - decrease the compressor rotation speed 7 when the determined temperature Tl of the indoor airflow Fi is greater than the setpoint temperature Tc_l. By reducing the rotation speed of the compressor 7, the refrigerant flow rate decreases, as does the thermal power supplied at the first exchanger 1. The temperature of the indoor air flow Fi, after heat exchange with the first exchanger 1, tends to approach its setpoint value. Regulating the rotation speed of the compressor 7 thus allows the temperature Tl of the internal airflow Fi to be regulated.

[0137] The control process includes the step: - determine a maximum permissible pressure Pmax of the refrigerant at the compressor outlet 7, - determine a pressure P_c of the refrigerant fluid at the outlet of compressor 7, - control a refrigerant expansion in the second expansion valve 32 so that the determined pressure P_c of the refrigerant at the outlet of the compressor 7 is less than the maximum permissible pressure Pmax.

[0138] The control process thus comprises the following substep: - decrease a cross-section of the refrigerant passage through the second expansion valve 32 if the determined pressure P_c of the refrigerant at the outlet of the compressor 7 is less than a target value.

[0139] The control method further comprising the substep: - increase a cross-section of the refrigerant passage through the second expansion valve 32 if the determined pressure P_c of the refrigerant at the outlet of the compressor 7 is greater than a target value.

[0140] Regulation of the cross-section of the refrigerant passing through the second expansion valve 32 thus makes it possible to regulate the pressure of the refrigerant at the outlet of the compressor 7.

[0141] The inspection process may include the following steps: - determine a maximum permissible temperature Tmax of the refrigerant at the compressor outlet 7, - determine a temperature T_c of the refrigerant fluid at the outlet of compressor 7, - control a refrigerant expansion in the first expansion valve 31 so that the determined temperature T_c is less than the maximum temperature Tmax.

[0142] The proposed control method thus comprises the following substep: - decrease a cross-section of the refrigerant passing through the first expansion valve 31 if the determined temperature T_c of the refrigerant at the outlet of the compressor 7 is greater than a target value.

[0143] The proposed control method further comprises the substep: - increase a cross-section of the refrigerant passing through the first expansion valve 31 if the determined temperature T_c of the refrigerant at the outlet of the compressor 7 is less than a target value.

[0144] Regulation of the cross-section of the refrigerant passing through the first expansion valve 31 thus makes it possible to regulate the temperature of the refrigerant at the outlet of the compressor 7.

[0145] Simultaneous adjustment of the rotational speed of the compressor 7, the passage area of ​​the first expansion valve 31 and the passage area of ​​the second expansion valve 32 makes it possible to simultaneously control the temperature of the internal airflow Fi, the discharge pressure of the compressor 7 and the discharge temperature of the compressor 7. The proposed type of control allows stable operation of the thermal conditioning system and a short response time when changes in setpoints or operating conditions.

Claims

1. Demands Method for controlling a thermal conditioning system for a motor vehicle, the thermal conditioning system (100) comprising a refrigerant circuit (10), the refrigerant circuit (10) comprising a main loop (A) comprising successively, according to the direction of refrigerant flow: - a compressor (7), - a first heat exchanger (1) thermally coupled with an interior airflow (Fi) to a vehicle passenger compartment, - a first regulator (31), - a second regulator (32), - a second heat exchanger (2) configured to exchange heat with an outside airflow (Fe) to the vehicle passenger compartment, - a refrigerant fluid accumulation device (8), the main loop (A) comprising an internal heat exchanger (6) configured to allow heat exchange between the refrigerant circulating between the first expansion valve (31) and the second expansion valve (32) and the refrigerant downstream of the accumulation device (8) and upstream of an inlet (7a) of the compressor (7), the process comprising the following successive steps: (i) provide a high-pressure refrigerant flow at the compressor outlet (7), (ii) circulate high-pressure refrigerant fluid through the first heat exchanger (1), (iii) reduce the high-pressure refrigerant from the first heat exchanger (1) to an intermediate pressure lower than the high pressure, (iv) circulate the intermediate pressure refrigerant fluid in the internal heat exchanger (6), (v) reduce the refrigerant from the internal heat exchanger (6) to a low pressure below the intermediate pressure, (vi) circulate the low-pressure refrigerant through the second heat exchanger (2), and in which the refrigerant circuit (10) comprises: - a first branch branch (B) connecting to a first connection point (11) located on the main loop (A) downstream of a

2. outlet (7b) of the compressor (7) and upstream of the first heat exchanger (1) to a second connection point (12) located on the main loop (A) downstream of the second heat exchanger (2) and upstream of the storage device (8), the first branch (B) comprising a third expansion valve (33), - a second branch (C) connecting a third connection point (13) located on the main loop (A) between the first heat exchanger (1) and the first expansion valve (31) to a fourth connection point (14) located on the main loop (A) downstream of the second heat exchanger (2) and upstream of the storage device (8), the second branch (C) comprising successively a fourth expansion valve (34) and a third heat exchanger (3) thermally coupled with an element (25) of an electric drive chain of a motor vehicle, - a third branch (D) connecting a fifth connection point (15) located on the main loop (A) between the second expansion valve (32) and the first expansion valve (31) to a sixth connection point (16) located on the main loop (A) between the second connection point (12) and the fourth connection point (14), the third branch (D) comprising successively a fifth expansion valve (35) and a fourth heat exchanger (4) configured to exchange heat with the indoor airflow (Fi), - a fourth branch (E) connecting a seventh connection point (17) located on the second branch (C) downstream of the third exchanger (3) and upstream of the fourth connection point (14) to an eighth connection point (18) located on the main loop (A) between the fifth connection point (15) and the second pressure regulator (32), in which the second branch (C) includes a sixth pressure regulator (36) located between the seventh connection point (17) and the fourth connection point (14), and in which: - the third regulator (33), the fourth regulator (34), the fifth regulator (35) and the sixth regulator (36) are jointly in the closed position. A control method according to claim 1, comprising the steps: - receive a temperature setpoint (Tc_l) of the indoor airflow (Fi) at the outlet of the first exchanger (1), - determine a temperature (Tl) of the indoor airflow (Fi) at the outlet of the first exchanger (1), - control a refrigerant flow in the refrigerant circuit (10) so that the determined temperature (Tl) of the indoor airflow (Fi) at the outlet of the first exchanger (1) is equal to the temperature setpoint (Tc_l).

3. A control method according to the preceding claim, comprising the step: - controlling a compressor rotation regime (7) in order to control the flow of refrigerant fluid in the refrigerant fluid circuit (10).

4. A control method according to the preceding claim, comprising the substeps: - increasing the rotation speed of the compressor (7) when the determined temperature (Tl) of the indoor airflow (Fi) is less than the setpoint temperature (Tc_l), - decreasing the rotation speed of the compressor (7) when the determined temperature (Tl) of the indoor airflow (Fi) is greater than the setpoint temperature (Tc_l).

5. A control method according to any one of the preceding claims, comprising the steps: - determining a maximum allowable pressure (Pmax) of the refrigerant at the outlet of the compressor (7), - determining a pressure (P_c) of the refrigerant at the outlet of the compressor (7), - controlling an expansion of the refrigerant in the second expansion valve (32) so that the determined pressure (P_c) of the refrigerant at the outlet of the compressor (7) is less than the maximum allowable pressure (Pmax).

6. A control method according to the preceding claim, comprising the following substeps: - decreasing the cross-sectional area of ​​the refrigerant flow through the second expansion valve (32) if the determined pressure (P_c) of the refrigerant at the outlet of the compressor (7) is less than a target value, - increasing the cross-sectional area of ​​the refrigerant flow through the second expansion valve (32) if the determined pressure (P_c) of the refrigerant refrigerant at compressor outlet (7) is greater than a target value.

7. A control method according to any one of the preceding claims, comprising the steps: - determining a maximum allowable temperature (Tmax) of the refrigerant at the outlet of the compressor (7), - determining a temperature (T_c) of the refrigerant at the outlet of the compressor (7), - controlling an expansion of the refrigerant in the first expansion valve (31) so that the determined temperature (T_c) is less than the maximum temperature (Tmax).

8. A control method according to the preceding claim, comprising the substeps: - decreasing a cross-section of the refrigerant through the first expansion valve (31) if the determined temperature (T_c) of the refrigerant at the outlet of the compressor (7) is greater than a target value, - increasing a cross-section of the refrigerant through the first expansion valve (31) if the determined temperature (T_c) of the refrigerant at the outlet of the compressor (7) is less than a target value.

9. A thermal conditioning system for a motor vehicle, comprising a refrigerant circuit (10) having: - A main loop (A) comprising successively, according to the direction of refrigerant flow: — a compressor (7), — a first heat exchanger (1) thermally coupled with an interior airflow (Fi) to a vehicle passenger compartment, — a first expansion valve (31), — a second expansion valve (32), — a second heat exchanger (2) configured to exchange heat with an exterior airflow (Fe) to the vehicle passenger compartment, — a refrigerant accumulation device (8), the main loop (A) comprising an internal heat exchanger (6) configured to allow heat exchange between the refrigerant flowing between the first expansion valve (31) and the second expansion valve (32) and the refrigerant downstream of the accumulation device (8) and upstream of an inlet (7a) of the compressor (7), - a first branch (B) connecting a first connection point (11) located on the main loop (A) downstream of an outlet (7b) of the compressor (7) and upstream of the first heat exchanger (1) to a second connection point (12) located on the main loop (A) downstream of the second heat exchanger (2) and upstream of the storage device (8), the first branch (B) including a third expansion valve (33), - a second branch (C) connecting a third connection point (13) located on the main loop (A) between the first heat exchanger (1) and the first expansion valve (31) to a fourth connection point (14) located on the main loop (A) downstream of the second heat exchanger (2) and upstream of the storage device (8),the second branch (C) comprising successively a fourth expansion valve (34) and a third heat exchanger (3) thermally coupled with an element (25) of an electric traction chain of a motor vehicle, - a third branch (D) connecting a fifth connection point (15) located on the main loop (A) between the second expansion valve (32) and the first expansion valve (31) to a sixth connection point (16) located on the main loop (A) between the second connection point (12) and the fourth connection point (14), the third branch (D) comprising successively a fifth expansion valve (35) and a fourth heat exchanger (4) configured to exchange heat with the indoor airflow (Fi), - a fourth branch branch (E) connecting a seventh connection point (17) disposed on the second branch branch (C) downstream of the third exchanger (3) and upstream of the fourth connection point (14) to an eighth connection point (18) disposed on the main loop (A) between the fifth connection point (15) and the second regulator (32), wherein the second branch branch (C) includes a sixth regulator (36) disposed between the seventh connection point (17) and the fourth connection point (14), - an electronic control unit (61) configured to implement the method according to any one of the preceding claims.

10. Thermal conditioning system (100) according to the preceding claim, comprising: - A fifth branch (F) connecting a ninth connection point (19) disposed on the main loop (A) downstream of the first connection point (11) and upstream of the first exchanger (1) to a tenth connection point (20) disposed on the second branch (C) downstream of the fourth regulator (34) and upstream of the seventh connection point (17), the fourth branch (E) comprising a seventh regulator (37).

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