Method for controlling a thermal conditioning system

Abstract

The invention relates to a method for controlling a thermal conditioning system (100) for an electric or hybrid vehicle, comprising: - a refrigerant circuit (10) including: - a compressor (7), - a first heat exchanger (1) thermally coupled to an airflow (Fi), - a second heat exchanger (2) thermally coupled to an airflow (Fe), - a third heat exchanger (3) thermally coupled to an element (25) of an electric powertrain of the vehicle via a heat transfer fluid circulating in a circuit (20), the control method comprising: - determining a value of a parameter representative of a temperature of the heat transfer fluid, - if the determined value of the temperature parameter (T3) of the heat transfer fluid is greater than a first predetermined threshold (s1): - circulating the refrigerant at high pressure in the first heat exchanger (1), - reducing the refrigerant to a low pressure,-- circulating the low-pressure refrigerant through the third heat exchanger (3). Figure from the abstract: Figure 6,

Description

Title of the invention: Method for controlling a thermal conditioning system. 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] In electric vehicles, climate control systems can commonly operate in a so-called heat pump mode. In this mode of operation, the heat of condensation of the high-pressure refrigerant is dissipated into the air supplying the vehicle's passenger compartment, and the heat of vaporization of the low-pressure refrigerant is supplied by the air outside the vehicle. The passenger compartment can thus be heated without the need for an additional heating device, such as an electric heater located in the passenger compartment. This mode of operation therefore allows the passenger compartment to be heated particularly efficiently, i.e., using very little electrical energy.

[0003] However, the efficiency of this operating mode decreases when the outside temperature drops. This is because the evaporation of the refrigerant, which occurs at a temperature lower than the outside temperature, tends to freeze the water vapor in the outside air. Ice deposits can then accumulate on the heat exchanger where the refrigerant evaporates. As ice accumulates, the efficiency of the heat exchange decreases, and this operating mode may become unusable. In this case, the use of an additional electric heater may be necessary to still heat the passenger compartment. The energy efficiency of the climate control system is then reduced, which degrades the vehicle's driving range.

[0004] It is therefore desirable to have thermal conditioning systems with improved energy efficiency, particularly in cold ambient temperatures. Summary

[0005] To this end, a method for controlling a thermal conditioning system for an electric or hybrid vehicle is proposed, the thermal conditioning system comprising: - a heat transfer fluid circuit, - a refrigerant circuit comprising: — a compressor configured to provide a high-pressure refrigerant flow, — a first heat exchanger thermally coupled to an airflow inside a vehicle passenger compartment, and configured to operate as a high-pressure refrigerant condenser, so as to heat the airflow, — a second heat exchanger thermally coupled to an external airflow to the vehicle's passenger compartment, configured to operate as a low-pressure refrigerant evaporator, — a third heat exchanger thermally coupled to an element of an electric powertrain of the vehicle via a heat transfer fluid circulating in the heat transfer fluid circuit, the third heat exchanger being configured to operate as a low-pressure refrigerant evaporator, the control method comprising: (i) determine a value for a first parameter representative of a temperature of the heat transfer fluid and a value for a second parameter representative of a temperature of the heat transfer fluid, (ii) if the determined value of the first parameter representing the temperature of the heat transfer fluid is greater than a first predetermined threshold and if the determined value of the second parameter representing the temperature of the heat transfer fluid is greater than a second predetermined threshold: (iiil) circulating the high-pressure refrigerant through the first heat exchanger so as to condense the refrigerant and heat the internal airflow, (iii2) reduce at least a portion of the refrigerant from the first heat exchanger to a low pressure lower than the high pressure, (iii3) circulate the refrigerant fluid at low pressure in the third exchanger so as to evaporate the refrigerant fluid.

[0006] The heat transfer fluid receives the heat losses resulting from the operation of the electric drive system element. When the heat transfer fluid is sufficiently hot, the energy required for the evaporation of the refrigerant during the thermodynamic cycle is supplied, at least in part, by this heat transfer fluid. The power drawn from the outside airflow is therefore reduced, which limits the risk of icing of the second heat exchanger.

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

[0008] According to one embodiment, the first exchanger is configured to exchange heat with an airflow inside the passenger compartment of a motor vehicle.

[0009] According to another 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 an airflow inside the vehicle's passenger compartment.

[0010] According to one embodiment, the second exchanger is configured to exchange heat with an outside airflow to the passenger compartment of a motor vehicle.

[0011] According to another embodiment, the second 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 an airflow outside the vehicle's passenger compartment.

[0012] The third exchanger is arranged jointly on the refrigerant circuit and on a heat transfer fluid circuit, so as to allow heat exchange between the refrigerant and the heat transfer fluid.

[0013] According to one embodiment, the element of the vehicle's electric powertrain includes an electrical energy storage battery.

[0014] According to one variant, or in a complementary manner, the element of the vehicle's electric drive chain includes an electric vehicle traction motor.

[0015] Alternatively, or in addition, the element of the vehicle's electric traction chain may include an electronic control unit for the vehicle's electric traction motor.

[0016] According to an example of implementation of the proposed control process, the first parameter representing a temperature of the heat transfer fluid is a temperature of the heat transfer fluid at the inlet of the third exchanger.

[0017] According to another example of implementation of the process, the second parameter representing a temperature of the heat transfer fluid is a temperature of the heat transfer fluid at the outlet of the third exchanger.

[0018] According to one example of implementation of the process, the first threshold determined is equal to the sum of a determined outside ambient temperature and a first predetermined positive value.

[0019] According to one example of implementation of the process, the second determined threshold is equal to the sum of a determined outside ambient temperature and a second predetermined negative value.

[0020] According to another example of implementation of the process, the second threshold determined is a constant value.

[0021] When the heat transfer fluid is at a temperature sufficiently higher than the ambient temperature, it is possible to extract energy from the heat transfer fluid without disturbing the operation of the vehicle's drivetrain element.

[0022] The first predetermined positive value is a constant value. The first predetermined positive value is, for example, 5 °C.

[0023] The second predetermined negative value is a constant value. The second predetermined negative value is, for example, -5 °C.

[0024] The proposed control method comprises: - determine an ambient outdoor temperature.

[0025] According to one aspect of the control method, the low-pressure refrigerant circulates in the third exchanger without circulating in the second exchanger.

[0026] When the temperature of the heat transfer fluid is sufficient, the heat required to evaporate the refrigerant and complete the thermodynamic cycle is drawn solely from the heat transfer fluid, and not from the outside airflow. The risk of icing of the second heat exchanger, operating in heat pump mode, is eliminated.

[0027] According to an example of implementation of the proposed control method, the step of circulating the low-pressure refrigerant fluid in the third exchanger without circulating in the second exchanger is applied at the start of the vehicle.

[0028] Thus, even if during the driving phase it becomes necessary to evaporate the refrigerant simultaneously in the second and third heat exchangers, using only the third heat exchanger when starting the vehicle delays the icing of the second heat exchanger. The availability of the heat pump mode is therefore improved.

[0029] According to another aspect of the control method, the low-pressure refrigerant circulates jointly in the third exchanger and in the second exchanger.

[0030] According to another aspect, the control method includes: - determining a temperature of the indoor airflow, - determining a setpoint temperature of the indoor airflow, - if, in steady-state operation in which the low-pressure refrigerant circulates in the third exchanger without circulating in the second exchanger, a difference between the temperature of the indoor airflow and the setpoint temperature is greater than a third predetermined threshold. - determine the difference between the temperature of the heat transfer fluid at the inlet of the third heat exchanger and the outside ambient temperature, - if the difference determined between the temperature of the heat transfer fluid at the inlet of the third heat exchanger and the outside ambient temperature is between a fourth negative threshold and a fifth positive threshold: — to circulate the low-pressure refrigerant fluid jointly in the third exchanger and in the second exchanger.

[0031] The steady-state operating condition can be determined from the time evolution of the temperature of the internal airflow.

[0032] The temporal evolution of the temperature of the indoor airflow can be determined over a predetermined time period.

[0033] The third predetermined threshold is for example between 0.5°C and 4°C, and is for example equal to 1°C.

[0034] The fourth negative threshold is for example -5°C. The fifth positive threshold is, for example, +5°C.

[0035] According to one example of implementation of the process, the low-pressure refrigerant flows in parallel in the third exchanger and in the second exchanger.

[0036] The low-pressure refrigerant circulates in both the third and second heat exchangers. The heat required to evaporate the refrigerant and complete the thermodynamic cycle is drawn partly from the heat transfer fluid and partly from the outside airflow. This reduces the risk of icing in the second heat exchanger.

[0037] According to one aspect of the control method, in which the heat transfer fluid circuit includes a heating device configured to heat the heat transfer fluid, the method comprises: - if, in steady-state operation in which the low-pressure refrigerant circulates jointly in the third and second heat exchangers, the difference between the temperature of the indoor airflow and the setpoint temperature exceeds a third predetermined threshold: - activate the heating device in order to heat the heat transfer fluid.

[0038] When the sum of the recoverable energy from the outside airflow and the recoverable energy from the thermal losses of the traction chain element is not sufficient to provide enough energy to heat the passenger compartment according to the setpoint received, the heat transfer fluid is heated by a heat transfer fluid heating device in order to increase the recoverable energy at the level of the second exchanger, and to allow the expected setpoint to be met.

[0039] The proposed control method comprises: - if, in steady-state operation in which the low-pressure refrigerant circulates jointly in the third and second heat exchangers, the difference between the temperature of the indoor airflow and the setpoint temperature is less than or equal to the third predetermined threshold: - keep the heating device inactive.

[0040] When the sum of the energy recoverable from the outside airflow and the energy recoverable from the thermal losses of the traction chain element is sufficient to allow the passenger compartment to be heated to the expected setpoint, the heating device is kept inactive in order to minimize the consumption of electrical energy and optimize the energy consumption of the vehicle.

[0041] The heating device is an electric heating device.

[0042] According to one aspect of the proposed process, in which the heat transfer fluid circuit includes a heating device configured to heat the heat transfer fluid, the process comprises: - if, in steady-state operation in which the low-pressure refrigerant circulates in the third heat exchanger without circulating in the second heat exchanger, the difference determined between the temperature of the heat transfer fluid at the inlet of the third heat exchanger and the outside ambient temperature is less than the fourth negative threshold or is greater than the fifth positive threshold: — circulating the low-pressure refrigerant fluid jointly through the third heat exchanger and the second heat exchanger, and — activate the heating device so as to heat the heat transfer fluid.

[0043] According to one embodiment, the control process includes a step of allowing circulation of low-pressure refrigerant fluid in the third exchanger.

[0044] The step of allowing circulation of low-pressure refrigerant fluid in the third exchanger can be a step of the process.

[0045] The refrigerant circulation authorization step is a prerequisite step to the low-pressure refrigerant circulation step in the third exchanger.

[0046] The step authorising the circulation of low-pressure refrigerant fluid in the third exchanger can be information received from an electronic unit separate from the electronic unit implementing the process.

[0047] The invention also relates to a thermal conditioning system comprising: - a heat transfer fluid circuit configured to circulate a heat transfer fluid, - a refrigerant circuit configured to circulate a refrigerant, the refrigerant circuit comprising: — A main loop comprising successively, according to the direction of flow of the refrigerant: — a compression device, — a first heat exchanger thermally coupled to an airflow, — a first regulator, — a second heat exchanger thermally coupled to an airflow, — a first branch connecting a first connection point located on the main loop downstream of the first heat exchanger and upstream of the first expansion valve to a second connection point located on the main loop downstream of the first heat exchanger and upstream of the compressor, the first branch successively comprising a second expansion valve and a third heat exchanger configured to exchange heat with the heat transfer fluid circulating in the heat transfer fluid circuit, - an electronic control unit configured to implement the process described above.

[0048] According to one embodiment, the thermal conditioning system comprises: - a second branch connecting a third connection point located on the first branch downstream of the first connection point and upstream of the second expansion valve to a fourth connection point located on the first branch downstream of the third heat exchanger and upstream of the second connection point, the second branch comprising successively a third expansion valve and a fourth heat exchanger thermally coupled with the indoor airflow.

[0049] The fourth heat exchanger is positioned upstream of the first heat exchanger in the direction of the flow of the internal air. In other words, the internal air flow first exchanges heat with the fourth heat exchanger and then with the first heat exchanger.

[0050] According to one embodiment of the thermal conditioning system, the main loop of the refrigerant circuit includes an accumulation device located downstream of the first exchanger and upstream of the first expansion valve.

[0051] Alternatively, the main loop of the refrigerant circuit includes an accumulation device located downstream of the second connection point and upstream of an inlet of the refrigerant compressor.

[0052] The heat transfer fluid circuit includes a circulation pump.

[0053] The invention also relates to a computer program stored in memory and configured to implement the process described above. Brief description of the drawings

[0054] Other features, details and advantages will become apparent upon reading the detailed description below, and upon analysis of the accompanying drawings, on which:

[0055] [Fig-1] is a schematic view of a first example of a system of thermal conditioning that can implement the proposed process

[0056] [Fig.2] is a schematic view of a second example of a system of thermal conditioning that can implement the proposed process

[0057] [Fig.3] is a schematic view of a first embodiment of the system of thermal conditioning of the [Fig.2],

[0058] [Fig.4] is a schematic view of a second embodiment of the system of thermal conditioning of the [Fig.2],

[0059] [Fig.5] is a block diagram of the proposed process.

[0060] [Fig.6] is a schematic view of the thermal conditioning system of the [Fig. 3], illustrating a first mode of operation,

[0061] [Fig.7] is a schematic view of the thermal conditioning system of the [Fig. 3], illustrating a second mode of operation,

[0062] [Fig.8] is a schematic view of the thermal conditioning system of the [Fig.4], illustrating a third mode of operation. Description of the implementation methods

[0063] 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 a priority of one element or parameter over another, and the designations may be interchanged.

[0064] In the following description, the expression "a first element upstream of a second element" means that the first element is placed before the second element with respect 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 placed after the second element with respect to the direction of flow, or path, of the fluid in question. In the case of the refrigerant circuit, the term "a first element is 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, then returns to the compression device, possibly after passing through other elements.

[0065] 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 passes through the second element.

[0066] When it is specified that a subsystem includes a given element, this does not exclude the presence of other elements in that subsystem.

[0067] The thermal conditioning system 100, which will be described below, comprises an electronic control unit 60 that receives information from various sensors measuring, in particular, the characteristics of the refrigerant at various points in the circuit. The electronic control unit 60 also receives instructions from the vehicle occupants, such as the desired temperature inside the passenger compartment. The electronic control unit 60 can also receive instructions from other electronic subsystems, such as the electrical energy storage battery management system. The electronic control unit 60 implements control laws to operate the various actuators in order to control the thermal conditioning system 100 and ensure compliance with the received instructions.

[0068] A compression device 7 allows a refrigerant to circulate in a refrigerant circulation circuit 10. The refrigerant circuit 10 forms a closed loop in which the refrigerant can circulate. The refrigerant circuit 10 is leak-proof when it is in its nominal operating condition, that is, without any faults or leaks. Each connection point of the circuit 10 allows the refrigerant to flow into one or the other of the circuit sections that converge at that connection point. The distribution of the refrigerant between the circuit sections that converge at a connection point is achieved by opening or closing the shut-off valves, check valves, or expansion devices included on each of these sections. In other words, each connection point is a means of redirecting the refrigerant arriving at that connection 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 ensure different operating modes, as will be described later.

[0069] The refrigerant used by the refrigerant circuit 10 is here a chemical fluid such as R1234yf, or 134a. A natural refrigerant, such as R290 or R744, can also be used.

[0070] 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 passes can be continuously adjusted. between a closed position and a maximum open position. For this, an electronic control module of the expansion valve drives an electric motor which moves a movable shutter controlling the passage cross-section offered to the refrigerant.

[0071] The heat transfer fluid circuit(s) also form one or more closed and sealed circuits in which a heat transfer fluid can circulate. The heat transfer fluid can exchange heat during its circulation.

[0072] 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.

[0073] The term "external airflow Fe" refers to an airflow that is not directed towards the vehicle's passenger compartment. In other words, this airflow Fe remains outside the vehicle's passenger compartment. A second motor-fan unit, also not shown, can be activated to increase the flow rate of the external airflow Fe if necessary. The airflow provided by both the first and second motor-fan units can be adjusted in real time according to heat exchange requirements, for example, by the electronic control unit of the climate control system 100.

[0074] The term "first exchanger" is equivalent to the term "first heat exchanger". The term "storage device" is equivalent to the term "refrigerant storage device".

[0075] A first example of a thermal conditioning system 100 has been schematically represented in [Fig.1]. The 100 thermal conditioning system includes: - a heat transfer fluid circuit 20 configured to circulate a heat transfer fluid, - a refrigerant circuit 10 configured to circulate a refrigerant. The refrigerant circuit 10 comprises a main loop A including, successively according to the direction of flow of the refrigerant: - a compression device 7, - a first heat exchanger 1 thermally coupled to an airflow Fi, - a first regulator 21, - a second heat exchanger 2 thermally coupled to an air flow Fe. The refrigerant circuit 10 includes a first branch B connecting a first connection point 11 located on the main loop A downstream of the first heat exchanger 1 and upstream of the first expansion valve 21 to a second point connection 12 arranged on the main loop A downstream of the first heat exchanger 1 and upstream of the compressor 7. The first branch B includes successively a second expansion valve 22 and a third heat exchanger 3 configured to exchange heat with the heat transfer fluid circulating in the heat transfer fluid circuit 20. The thermal conditioning system 100 includes an electronic control unit 60 configured to implement a process which will be described in detail below.

[0076] The thermal conditioning system 100 is here a thermal conditioning system for a motor vehicle.

[0077] The first exchanger 1 can receive the high-pressure, high-temperature refrigerant fluid discharged by the compressor 7. The second exchanger 2 can receive the refrigerant from the first expansion valve 21. The second exchanger 2 can therefore receive low-pressure refrigerant.

[0078] The third exchanger 3 is arranged jointly on the refrigerant circuit 10 and on a heat transfer fluid circuit 20, so as to allow heat exchange between the refrigerant and the heat transfer fluid. The third exchanger 3 includes a refrigerant inlet and a refrigerant outlet, as well as a heat transfer fluid inlet and a heat transfer fluid outlet. The refrigerant and the heat transfer fluid can exchange heat in the third exchanger 3.

[0079] The third heat exchanger 3 is thermally coupled with an element 25 of an electric powertrain of the vehicle. The thermal coupling is achieved via a heat transfer fluid circulating in the heat transfer fluid circuit 20. Element 25 is part of circuit 20, and the heat transfer fluid can circulate in element 25 and exchange heat. The third exchanger 3 can receive the refrigerant from the second expansion valve 22. The third exchanger 3 can therefore receive low-pressure refrigerant. The third exchanger 3 thus allows the element 25 to be cooled, or at least partially recovered from the heat dissipated by the operation of the element 25.

[0080] According to one embodiment, element 25 of the vehicle's electric drive chain includes an electrical energy storage battery. According to one variant, or in a complementary manner, element 25 of the vehicle's electric drive chain includes an electric vehicle traction motor. Alternatively, or as a complement, element 25 of the vehicle's electric drive chain may include an electronic control unit for the vehicle's electric traction motor.

[0081] The heat transfer fluid circuit 20 includes a circulation pump 17. The pump 17 is, for example, an electrically controlled pump. The pump 17 can be selectively switched on or off. Pump 17, when activated, allows the heat transfer fluid to circulate in the heat transfer fluid circuit 20. The heat transfer fluid is, for example, a mixture of water and glycol.

[0082] Figure 2 schematically represents a second example of a thermal conditioning system 100 on which the proposed method can be implemented. According to this second example, the thermal conditioning system 100 comprises a second branch C connecting a third connection point 13 located on the first branch B downstream of the first connection point 11 and upstream of the second expansion valve 22 to a fourth connection point 14 located on the first branch B downstream of the third heat exchanger 3 and upstream of the second connection point 12. The second branch of the C branch successively includes a third expansion valve 23 and a fourth heat exchanger 4 thermally coupled with the internal airflow Fi.

[0083] The fourth exchanger 4 can receive the refrigerant from the third expansion valve 23. The fourth exchanger 4 can therefore receive low-pressure refrigerant. The fourth exchanger 4 is located in the heating, ventilation and / or air conditioning system. The interior airflow Fi reaches the surface of the fourth exchanger 4, which allows heat exchange between the interior airflow circulating outside the fourth exchanger 4 and the refrigerant circulating inside the fourth exchanger 4. The fourth exchanger 4, called the passenger compartment evaporator, cools the passenger compartment of the vehicle.

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

[0085] According to one embodiment, illustrated in particular in [Fig.3], the first exchanger 1 is configured to exchange heat with an internal airflow Fi to the passenger compartment of a motor vehicle. The thermal coupling between the first exchanger 1 and the internal airflow Fi is then said to be direct. The first heat exchanger 1 is located in the vehicle's heating, ventilation and / or air conditioning system. The fourth heat exchanger 4 is arranged upstream of the first heat exchanger 1 according to a flow direction of the indoor airflow Fi. In other words, the indoor airflow Fi first exchanges heat with the fourth heat exchanger 4 and then with the first heat exchanger 1.

[0086] The embodiment of [Fig.3] is based on the second example, shown in [Fig.2], in which the third branch branch C and the fourth heat exchanger 4 are present. This embodiment is also applicable to the first example in which the third branch of derivation C is not present.

[0087] According to another embodiment, illustrated in [Fig.4], the first heat exchanger 1 is configured to exchange heat with a heat transfer fluid circulating in a closed heat transfer fluid circuit 30, the heat transfer fluid circuit 30 comprising a heat exchanger IA configured to exchange heat with an interior airflow Fi to the vehicle's passenger compartment. The thermal coupling between the first exchanger 1 and the indoor airflow Fi is in this case said to be indirect. The IA exchanger, also known as the heater radiator, is located in the vehicle's heating, ventilation and / or air conditioning system. The heating radiator is downstream of the fourth exchanger 4 according to the direction of flow of the indoor air flow Fi. The heat transfer fluid circuit 30 includes a circulation pump, not shown.

[0088] As before, the embodiment of [Fig.4] is based on the second example, shown in [Fig.2], which includes the third branch of bypass C and the fourth exchanger 4. This embodiment is also applicable to the first example in which the third branch of derivation C is not present.

[0089] Similarly, the thermal coupling between the second exchanger 2 and the outside airflow Fe can be ensured directly or indirectly.

[0090] According to the embodiment illustrated in [Fig.3], the second exchanger 2 is configured to exchange heat with an outside airflow Fe to the passenger compartment of a motor vehicle. The thermal coupling between the second exchanger 2 and the outside airflow Fe is then said to be direct. The second interchange 2 is located in the front of the vehicle, for example just behind the grille. The outside airflow Fe thus reaches the surface of the second exchanger 2 directly.

[0091] According to the embodiment illustrated in [Fig.4], the second exchanger 2 is configured to exchange heat with a heat transfer fluid circulating in a closed heat transfer fluid circuit 40, the heat transfer fluid circuit 40 comprising a heat exchanger 2A configured to exchange heat with an outside airflow Fe to the vehicle's passenger compartment. The thermal coupling between the second exchanger 2 and the outside air flow Fe is in this case said to be indirect. The 2A intercooler, also known as the external radiator, is located in the front of the vehicle, for example just behind the grille. The heat transfer fluid circuit 40 includes a circulation pump, not shown.

[0092] According to the illustrated examples, the main loop of the refrigerant circuit includes an accumulation device 9 located downstream of the first exchanger 1 and upstream of the first expansion valve 21. The accumulation device 9 makes it possible to compensate for variations, depending on the operating mode used and the thermal operating conditions, in the mass of refrigerant circulating in the refrigerant circuit 10. Accumulation device 9 is a desiccant bottle.

[0093] According to an unrepresented variant, the main loop A of the refrigerant circuit 10 includes an accumulation device disposed downstream of the second connection point 12 and upstream of an inlet 7a of the refrigerant compressor 7. The accumulation device is then called an accumulator.

[0094] The main loop A includes a 4L one-way valve The one-way valve 41 is configured to allow refrigerant flow through valve 41 from the second connection point 12 to the second exchanger 2, and is configured to prohibit refrigerant flow through valve 41 from the second exchanger 2 to the second connection point 12. The one-way valve 41 is, for example, a non-return valve.

[0095] The thermal conditioning system can operate according to various operating modes.

[0096] One of these operating modes, called a heat pump, allows the passenger compartment to be heated by recovering energy from the outside air Fe, which is at ambient temperature. For this, the refrigerant fluid discharged by the compressor 7 in a state of high pressure and high temperature is condensed in the first exchanger 1, which allows the interior airflow Fi to be heated, either directly or indirectly, as seen previously. The refrigerant from the first heat exchanger 1 is expanded by the first expansion valve 21 to a low-pressure state, the low pressure being lower than the high pressure. The expanded refrigerant circulates in the second heat exchanger 2 and evaporates. The heat of vaporization is extracted from the outside air stream Fe. The evaporated refrigerant from the second exchanger 2 joins the inlet 7a of the compressor 7, thus completing the thermodynamic cycle.

[0097] In this operating mode known as heat pump, the heat extracted from the ambient air helps to heat the passenger compartment of the vehicle, which allows the passenger compartment to be heated with good energy efficiency. However, when this operating mode is used in cold ambient temperatures, the second heat exchanger 2 is susceptible to frosting, meaning it becomes covered in ice. This is because the heat absorbed by the evaporation of the refrigerant can cause the water vapor in the outside air stream Fe to freeze solid. This ice accumulates on the surface of the second heat exchanger 2 and impairs the heat exchange between the refrigerant and the outside air stream Fe. The available heating capacity decreases, and this operating mode can become unusable when the heat exchange becomes too weak. A cold ambient temperature is defined as a temperature close to 0°C, or below 0°C. Heat sources other than ambient air can contribute to heating the passenger compartment.

[0098] A method for controlling a thermal conditioning system 100 for an electric or hybrid vehicle is thus proposed, the thermal conditioning system 100 comprising: - a 20-circuit heat transfer fluid system, - a refrigerant fluid circuit 10 comprising: — a compressor 7 configured to provide a high-pressure refrigerant flow, — a first heat exchanger 1 thermally coupled to an airflow Fi inside a vehicle passenger compartment, and configured to operate as a high-pressure refrigerant condenser, so as to heat the airflow Fi, — a second heat exchanger 2 thermally coupled to an external airflow Fe outside the vehicle's passenger compartment, configured to operate as a low-pressure refrigerant evaporator, — a third heat exchanger 3 thermally coupled with an element 25 of an electric drive chain of the vehicle via a heat transfer fluid circulating in the heat transfer fluid circuit 20, the third heat exchanger 3 being configured to operate as a low-pressure refrigerant fluid evaporator. The proposed control procedure includes: (i) determine a value for a first parameter representative of a temperature of the heat transfer fluid and a value for a second parameter representative of a temperature of the heat transfer fluid, (ii) if the determined value of the first parameter representing the temperature of the heat transfer fluid is greater than a first threshold if predetermined and if the determined value of the second parameter representing the temperature of the heat transfer fluid is greater than a second predetermined threshold s2: (iiil) circulating the high-pressure refrigerant through the first heat exchanger 1 so as to condense the refrigerant and heat the indoor airflow Fi, (iii2) reducing at least a portion of the refrigerant from the first heat exchanger 1 to a low pressure lower than the high pressure, (iii3) circulate the refrigerant fluid at low pressure in the third exchanger 3 so as to evaporate the refrigerant fluid.

[0099] The heat transfer fluid of circuit 20 receives the heat losses resulting from the operation of the element 25 of the electric traction chain. When the heat transfer fluid is sufficiently hot, the energy required for the evaporation of the refrigerant during the thermodynamic cycle is supplied at least in part by this heat transfer fluid. The power drawn from the outside airflow Fe can therefore be reduced, which limits the risk of icing of the second heat exchanger 2.

[0100] The term "operating as a high-pressure refrigerant condenser" means condensing at least part of the refrigerant. The condensed fraction, for example, is greater than 80%. Operating as a low-pressure refrigerant evaporator means evaporating at least part of the refrigerant. The evaporated fraction, for example, is greater than 80%.

[0101] According to an example of implementation of the proposed control process, the first parameter representative of a temperature of the heat transfer fluid is a temperature T3a of the heat transfer fluid at the inlet of the third exchanger 3.

[0102] According to this example of implementation of the process, the second parameter representing a temperature T3 of the heat transfer fluid is a temperature T3b of the heat transfer fluid at the outlet of the third exchanger 3.

[0103] The first threshold determined if is equal to the sum of a determined outside ambient temperature Text and a first predetermined positive value. The first predetermined positive value is a constant value. The first predetermined positive value is, for example, 5°C.

[0104] The second determined threshold s2 is equal to the sum of the determined outside ambient temperature Text and a second predetermined negative value. The second predetermined negative value is a constant value. The second predetermined negative value is, for example, -5°C.

[0105] When the heat transfer fluid circulating in the heat transfer fluid circuit 20 is at a temperature sufficiently higher than the ambient temperature, and also above a predetermined minimum threshold, it is possible to extract energy from the heat transfer fluid without disrupting the operation of the vehicle's powertrain component 25. The third heat exchanger 3 is thus used to evaporate at least part of the refrigerant.

[0106] In other words, step (ii) comprises two cumulative conditions, that is to say, conditions which must be verified simultaneously. A first condition relates to the temperature T3a of the heat transfer fluid at the inlet of the third exchanger 3, and a second condition relates to the temperature T3b of the heat transfer fluid at the outlet of the third exchanger 3. If the temperature T3a of the heat transfer fluid at the inlet of the third exchanger 3 is sufficiently above the ambient temperature, for example at least 5°C above the ambient temperature, and if at the same time the temperature T3b of the heat transfer fluid at the outlet of the third exchanger 3 is above a minimum threshold, for example 5°C below the ambient temperature, steps (üil), (iii2), (iii3) are carried out.

[0107] The ambient temperature Text is an input variable for the proposed control law. The proposed control procedure thus includes: - determining an external ambient temperature. The external temperature is determined, for example, by a direct measurement using a sensor located outside the vehicle.

[0108] According to a first mode of operation, illustrated in [Fig.6], the low-pressure refrigerant circulates in the third exchanger 3 without circulating in the second exchanger 2. This operating mode is referred to as energy recovery mode.

[0109] For this, the first expansion valve 21 is in the closed position. There is no refrigerant circulation in the main loop A between the first connection point 11 and the second connection point 12. Similarly, the third expansion valve 23 is in the closed position, and there is no refrigerant fluid circulation in the second branch of the bypass B.

[0110] When the temperature of the heat transfer fluid in circuit 20 is sufficient, the heat required to evaporate the refrigerant and complete the thermodynamic cycle is taken solely from this heat transfer fluid, and not from the outside air flow Fe. The risk of icing of the second heat exchanger 2, when operating in heat pump mode, is eliminated.

[0111] This step of circulating the refrigerant fluid at low pressure in the third exchanger 3 without circulating in the second exchanger 2 can in particular be applied to the starting of the vehicle.

[0112] In other words, if at the start of the vehicle the heat transfer fluid in circuit 20 is sufficiently hot, with both of the aforementioned conditions satisfied, the heating of the passenger compartment is achieved without taking heat from the outside airflow Fe at the level of the second exchanger 2, and by taking heat only from the heat transfer fluid of circuit 20, at the level of the third exchanger 3.

[0113] Thus, even if during a later driving phase it becomes necessary to carry out the evaporation of the refrigerant jointly in the second heat exchanger 2 and in the third heat exchanger 3, using only the third heat exchanger 3 when starting the vehicle makes it possible to delay the icing of the second heat exchanger 2. The availability of the heat pump mode is thus improved.

[0114] According to a second mode of operation, the low-pressure refrigerant circulates jointly in the third exchanger 3 and in the second exchanger 2.

[0115] Once the energy recovery mode is activated, it is checked whether the thermal power recovered from the heat transfer fluid at the level of the third exchanger 3 is sufficient to ensure sufficient heating at the level of the first exchanger 1.

[0116] The control method thus comprises: - determine a temperature of the indoor airflow Fi, - determine a setpoint temperature Te for the indoor airflow Fi, - if, in steady-state operation in which the low-pressure refrigerant circulates in the third exchanger 3 without circulating in the second exchanger 2, a difference between the temperature of the indoor air flow Fi and the setpoint temperature Te is greater than a third predetermined threshold s3. - determine the difference between the temperature T3a of the heat transfer fluid at the inlet of the third heat exchanger 3 and the ambient outside temperature (Text), - if the difference determined between the temperature T3a of the heat transfer fluid at the inlet of the third heat exchanger 3 and the outside ambient temperature Text is between a fourth negative threshold s4 and a fifth positive threshold s5: — circulating the low-pressure refrigerant fluid jointly in the third exchanger 3 and in the second exchanger 2.

[0117] The steady-state operating condition can be determined from the time evolution of the temperature of the internal airflow Fi. The temporal evolution of the temperature of the indoor airflow Fi can be determined over a predetermined time period. The predetermined duration for evaluating the steady-state operating condition is, for example, between 30 seconds and 2 minutes.

[0118] The third predetermined threshold s3 is for example between 0.5°C and 4°C, and is for example equal to 1°C. The fourth negative threshold s4 is, for example, -5°C. The fifth positive threshold s5 is, for example, +5°C.

[0119] In other words, when the temperature of the indoor airflow Fi is too far, in steady state, from its setpoint temperature, the process determines the difference between the temperature of the heat transfer fluid of the circuit 20 and the outside ambient temperature Text. If this temperature of the heat transfer fluid is located in a range of for example plus or minus 5°C around the ambient temperature Text, the circulation of refrigerant fluid in the second exchanger 2 is activated, in addition to the circulation in the third exchanger 3. This second mode of operation is referred to as energy recovery mode and heat pump.

[0120] According to the illustrated example, the low-pressure refrigerant flows in parallel in the third exchanger 3 and in the second exchanger 2.

[0121] The low-pressure refrigerant circulates in both the third heat exchanger 3 and the second heat exchanger 2. Part of the refrigerant evaporates in the third heat exchanger 3, and another part evaporates in the second heat exchanger 2. The heat required to evaporate the refrigerant and complete the thermodynamic cycle is drawn partly from the heat transfer fluid in circuit 20, and partly from the outside airflow Fe. The risk of icing of the second heat exchanger 2 is thus reduced.

[0122] This second mode of operation, called energy recovery and heat pump mode, is schematically represented in [Fig.7]. In [Fig. 7], the thermal coupling of the first heat exchanger 1 with the indoor airflow Fi is direct. The direct thermal coupling of the second heat exchanger 2 with the outdoor airflow Fe is also direct.

[0123] A flow rate Qr of refrigerant is discharged at high pressure by the compressor 7. The high-pressure refrigerant circulates in the first heat exchanger 1 and condenses. At the first connection point 11, the refrigerant flow rate Qr splits into a flow rate Qrl circulating in the main loop A towards the first regulator 21, and a flow Qr2 circulating in the first branch of bypass B towards the third connection point 13. The Qrl flow of refrigerant fluid is expanded by passing through the first expansion valve 21 and goes to low pressure, the low pressure being lower than the high pressure. The low-pressure refrigerant fluid from the first expansion valve 21 circulates in the second exchanger 2 and evaporates, then reaches the second connection point 12. The refrigerant flow Qr2 circulates through the second expansion valve 22 and drops to low pressure. The low-pressure refrigerant from the second expansion valve 22 circulates through the third heat exchanger 3 and evaporates, then passes through the fourth connection point 14 and returns to the second connection point 12. The respective passage section of the first regulator 21 and the second regulator 22 allows the distribution of the total flow Qr to be adjusted into a part Qrl circulating in the second exchanger 2 and a complementary part Qr2 circulating in the third exchanger 3. The Qrl and Qr2 flow rates meet at the second connection point 12. The flow rate formed by the combination of these two low-pressure refrigerant flow rates returns to the inlet 7a of the compressor 7. Figures 7 and 8 illustrate steady-state operation. The outflow rate of a heat exchanger is therefore equal to the inflow rate. A flow Qc of heat transfer fluid circulates in the circuit 20, and passes through the pump 17, the third exchanger 3 and the element 25.

[0124] Once the energy recovery and heat pump mode is activated, it is again checked whether the thermal power recovered by the two exchangers 2, 3 is sufficient to ensure adequate heating.

[0125] According to one aspect of the method for controlling the thermal conditioning system 100, in which the heat transfer fluid circuit 20 includes a heating device 15 configured to heat the heat transfer fluid, the method comprises: - if, in steady-state operation in which the low-pressure refrigerant circulates jointly in the third heat exchanger 3 and in the second heat exchanger 2, a difference between the temperature of the indoor air flow Fi and the setpoint temperature Te is greater than a third predetermined threshold s3: - activate the heating device 15 in order to heat the heat transfer fluid.

[0126] This operating mode, referred to as the third operating mode, is illustrated in [Fig. 8]. The activation of the electric heater 15 is schematically represented by a thick, solid line for the frame symbolizing the electric heater 15. In [Fig. 8], the thermal coupling of the first heat exchanger 1 with the indoor airflow Fi is indirect. The same is true for the thermal coupling of the second heat exchanger 2 with the outdoor airflow Fe. This mode of operation could of course be implemented with a system in which the thermal couplings are direct.

[0127] In [Fig.7], the heating device 15 is not activated, which is symbolized by the dotted line for the frame symbolizing electric heating 15.

[0128] An excessive difference between the actual temperature of the air blown into the passenger compartment and the setpoint temperature, during so-called steady-state operation, indicates that the combined energy recoverable from the outside airflow Fe and the energy recoverable from the heat losses of the powertrain element 25 is insufficient to provide enough energy to heat the passenger compartment according to the received temperature setpoint. A heating device 15 for the heat transfer fluid is therefore activated in order to increase the energy recoverable at the second heat exchanger 2 and thus increase the heating capacity. The temperature setpoint can then be reached.

[0129] The third predetermined threshold s3 is here the same as that used previously. According to one variant, a threshold with a different value may be used.

[0130] When the difference between the actual temperature of the air blown into the passenger compartment and the setpoint temperature is sufficiently small, it is not necessary to activate the heating device 15.

[0131] The proposed control method thus comprises: - if, in steady-state operation in which the low-pressure refrigerant circulates jointly in the third heat exchanger 3 and in the second heat exchanger 2, a difference between the temperature of the indoor air flow Fi and the setpoint temperature Te is less than or equal to the third predetermined threshold s3: - keep the heating device 15 inactive.

[0132] When the combined thermal power recovered from the outside airflow Fe and the thermal power recovered from the traction chain element 25 is sufficient to heat the passenger compartment according to the setpoint, the heating device 15 remains inactive. The vehicle's electrical energy consumption is thus optimized.

[0133] The heating device 15 is an electric heating device. The heating device 15 includes an electrical resistance that can dissipate heat when an electric current passes through it. The dissipated heat warms the heat transfer fluid. The heating device 15 can be selectively activated or deactivated, by circulating electric current or by interrupting the circulation of electric current.

[0134] According to the above, when the energy recovery mode is not sufficient to obtain sufficient heating power, the thermal conditioning system 100 first switches to the energy recovery and heat pump mode. If activating this mode is still not enough to obtain sufficient heating power, electric heating 15 is then activated in order to increase the recoverable thermal power. In other words, the transition from the initial energy recovery mode to the energy recovery and heat pump mode with electric heating activated is done with an intermediate step. The switch from energy recovery mode to energy recovery and heat pump mode with electric heating activated can also be done without an intermediate step. In other words, the system switches directly from the initial energy recovery mode to energy recovery and heat pump mode with electric heating also activated. This direct transition occurs when the thermal power of the energy recovery mode is insufficient and the temperature of the heat transfer fluid in circuit 20 is not within the range of plus or minus 5°C around the ambient temperature.

[0135] Thus, according to one aspect of the proposed process, in which the heat transfer fluid circuit 20 comprises a heating device 15 configured to heat the heat transfer fluid, The process involves: - if, in steady-state operation where the low-pressure refrigerant circulates in the third heat exchanger 3 without circulating in the second heat exchanger 2, the difference determined between the temperature T3a of the heat transfer fluid at the inlet of the third heat exchanger 3 and the outside ambient temperature Text is less than the fourth negative threshold s4 or is greater than the fifth positive threshold s5: — circulate the low-pressure refrigerant simultaneously in the third heat exchanger 3 and in the second heat exchanger 2, and — activate the heating device 15 so as to heat the heat transfer fluid.

[0136] The control process includes a step of allowing circulation of low-pressure refrigerant fluid in the third exchanger 3.

[0137] The refrigerant circulation authorization step is a prerequisite to the low-pressure refrigerant circulation step in the third exchanger 3.

[0138] According to one embodiment, the step of allowing circulation of low-pressure refrigerant fluid in the third exchanger 3 can be a step of the proposed process.

[0139] According to another embodiment, the step of authorizing the circulation of low-pressure refrigerant fluid in the third exchanger 3 can be information received from an electronic unit separate from the electronic unit 60 implementing the process.

[0140] The authorization may be information received by a digital communication protocol between the control unit 60 implementing the proposed process and a control unit managing the operation of the electrical energy storage battery 25.

[0141] The process described above can be coded in the form of a computer program. The computer program is stored in memory and is configured to implement the described process.

Claims

1. Demands Method for controlling a thermal conditioning system (100) for an electric or hybrid vehicle, the thermal conditioning system (100) comprising: - a heat transfer fluid circuit (20), - a refrigerant circuit (10) comprising: — a compressor (7) configured to supply a high-pressure refrigerant flow, — a first heat exchanger (1) thermally coupled to an airflow (Fi) inside a vehicle passenger compartment, and configured to operate as a high-pressure refrigerant condenser, so as to heat the airflow (Fi), — a second heat exchanger (2) thermally coupled to an airflow (Fe) external to the vehicle's passenger compartment, configured to operate as a low-pressure refrigerant evaporator, — a third heat exchanger (3) thermally coupled with an element (25) of an electric drive chain of the vehicle via a heat transfer fluid circulating in the heat transfer fluid circuit (20), the third heat exchanger (3) being configured to operate as a low-pressure refrigerant fluid evaporator, the control process comprising: (i) determine a value of a first parameter representing a temperature of the heat transfer fluid and a value of a second parameter representing a temperature of the heat transfer fluid, (ii) if the determined value of the first parameter representing the temperature of the heat transfer fluid is greater than a predetermined first threshold (s1) and if the determined value of the second parameter representing the temperature of the heat transfer fluid is greater than a predetermined second threshold (s2): (iiil) circulating the high-pressure refrigerant through the first heat exchanger (1) so as to condense the refrigerant and heat the internal airflow (Fi), (iii2) reduce at least a portion of the refrigerant from the first heat exchanger (1) to a low pressure lower than the high pressure, (iii3) circulating the refrigerant fluid at low pressure in the third exchanger (3) so as to evaporate the refrigerant fluid.

2. A control method according to claim 1, wherein the first parameter representing a temperature of the heat transfer fluid is a temperature (T3a) of the heat transfer fluid at the inlet of the third exchanger (3), and wherein the first determined threshold (si) is equal to the sum of a determined outside ambient temperature (Text) and a first predetermined positive value.

3. A control method according to any one of the preceding claims, wherein the second parameter representing a temperature of the heat transfer fluid is a temperature (T3b) of the heat transfer fluid at the outlet of the third exchanger (3), and wherein the first determined threshold (s2) is equal to the sum of a determined outside ambient temperature (Text) and a second predetermined negative value.

4. A control method according to any one of claims 1 to 3, wherein the low-pressure refrigerant circulates in the third exchanger (3) without circulating in the second exchanger (2).

5. A control method according to the preceding claim, wherein the step of circulating the refrigerant fluid at low pressure in the third exchanger (3) without circulating in the second exchanger (2) is applied at the start of the vehicle.

6. A control method according to any one of claims 1 to 3, wherein the low-pressure refrigerant circulates jointly in the third exchanger (3) and in the second exchanger (2).

7. A control method according to any one of the preceding claims, comprising: - determining an internal airflow temperature (Fi), - determining a setpoint temperature (Te) of the internal airflow (Fi), - whether, in steady-state operation in which the low-pressure refrigerant circulates in the third heat exchanger (3) without circulating in the second heat exchanger (2), a deviation between the If the temperature of the indoor airflow (Fi) and the setpoint temperature (Te) is greater than a third predetermined threshold (s3): - determine a difference between the temperature (T3a) of the heat transfer fluid at the inlet of the third exchanger (3) and the outside ambient temperature (Text), - if the difference determined between the temperature (T3a) of the heat transfer fluid at the inlet of the third exchanger (3) and the outside ambient temperature (Text) is between a fourth negative threshold (s4) and a fifth positive threshold (s5): — circulate the refrigerant fluid at low pressure jointly in the third exchanger (3) and in the second exchanger (2).

8. A control method according to the preceding claim, wherein the low-pressure refrigerant flows in parallel in the third exchanger (3) and in the second exchanger (2).

9. A control method according to claim 7 or 8, wherein the heat transfer fluid circuit (20) includes a heating device (15) configured to heat the heat transfer fluid, the method comprising: - if, in steady-state operation in which the low-pressure refrigerant circulates jointly in the third heat exchanger (3) and in the second heat exchanger (2), a difference between the temperature of the indoor airflow (Fi) and the setpoint temperature (Te) is greater than a third predetermined threshold (s3): - activating the heating device (15) so as to heat the heat transfer fluid.

10. A control method according to claim 7 or 8, comprising: - if, in steady-state operation in which the low-pressure refrigerant circulates jointly in the third exchanger (3) and in the second exchanger (2), a difference between the temperature of the indoor airflow (Fi) and the setpoint temperature (Te) is less than or equal to the third predetermined threshold (s3): - keep the heating device (7) inactive.

11. A method according to any one of claims 7 to 10, wherein the heat transfer fluid circuit (20) comprises a heating device (15) configured to heat the heat transfer fluid, the method comprising: - if, in steady-state operation in which the low-pressure refrigerant circulates in the third heat exchanger (3) without circulating in the second heat exchanger (2), the difference determined between the temperature (T3a) of the heat transfer fluid at the inlet of the third heat exchanger (3) and the outside ambient temperature (Text) is less than the fourth negative threshold (s4) or is greater than the fifth positive threshold (s5): — circulate the low-pressure refrigerant fluid jointly in the third heat exchanger (3) and in the second heat exchanger (2), and — activate the heating device (15) so as to heat the heat transfer fluid.

12. A control method according to any one of the preceding claims, comprising a step of allowing circulation of low-pressure refrigerant fluid in the third exchanger (3).

13. Thermal conditioning system (100) comprising: - a heat transfer fluid circuit (20) configured to circulate a heat transfer fluid, - a refrigerant fluid circuit (10) configured to circulate a refrigerant fluid, the refrigerant fluid circuit (10) comprising: — A main loop (A) comprising successively, according to the direction of flow of the refrigerant fluid: — a compression device (7), — a first heat exchanger (1) thermally coupled to an airflow (Fi), — a first expansion valve (21), — a second heat exchanger (2) thermally coupled to an airflow (Fe), — a first branch (B) connecting a first connection point (11) located on the main loop (A) downstream of the first heat exchanger (1) and upstream of the first expansion valve (21) to a second connection point (12) located on the main loop (A) downstream of the first heat exchanger (1) and upstream of the compressor (7),the first branch of the bypass (B) comprising successively a second expansion valve (22) and a third heat exchanger (3) configured to exchange heat with the heat transfer fluid circulating in the heat transfer fluid circuit (20),

14.

15. - an electronic control unit (60) configured to implement the process according to any one of the preceding claims. Thermal conditioning system (100) according to the preceding claim, comprising: - a second branch branch (C) connecting a third connection point (13) located on the first branch branch (B) downstream of the first connection point (11) and upstream of the second expansion valve (22) to a fourth connection point (14) located on the first branch branch (B) downstream of the third heat exchanger (3) and upstream of the second connection point (12), the second branch branch (C) comprising successively a third expansion valve (23) and a fourth heat exchanger (4) thermally coupled with the indoor airflow (Fi). Computer program stored in memory and configured to implement the method according to any one of claims 1 to 12.

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