Method for controlling a thermal conditioning system for a motor vehicle

Abstract

The invention relates to a method for controlling a thermal conditioning system comprising: - a main refrigerant circulation loop (A) (10) including: - a compressor (7), - a first heat exchanger (1), - a first expansion valve (31), - a second expansion valve (32), - a second heat exchanger (2), - a first bypass branch (B) including a third expansion valve (33), - a fourth bypass branch (E) including a fifth expansion valve (35), the method comprising the steps: (ii) circulating high-pressure refrigerant through the first heat exchanger (1), through the first branch (B) and through the fourth branch (E), (iv) reducing the refrigerant from the first heat exchanger (1) and the fourth branch (E) to an intermediate pressure, and circulating it through the third heat exchanger (3),(vi) reduce the refrigerant from the third heat exchanger (3) to a low pressure and mix it with the low-pressure refrigerant from the first branch (B). Figure 3,

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 minimizes the global warming potential (GWP) of the refrigerant used. 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, in particular, heating and cooling the vehicle cabin, as well as heating and cooling electrical energy storage batteries.

[0003] According to a heat pump operating mode, the high-pressure refrigerant transfers heat to the air supplying the vehicle's passenger compartment at a first heat exchanger, then expands to a low-pressure state. The low-pressure refrigerant is evaporated in a second heat exchanger by receiving heat from an outside airflow. This outside airflow is thus cooled as it passes through the second heat exchanger. When the ambient temperature is below freezing or close to 0°C, the water vapor in the outside air is likely to freeze and accumulate on the second heat exchanger. Heat exchange is then impaired, and the heating capacity available to the passenger compartment decreases as ice accumulates. Operation in this heat pump mode may become impossible.It may then become necessary to defrost this heat exchanger, that is, to melt the accumulated ice. on its surface. A specific operating mode is then activated. In this defrosting mode, it is generally not possible to simultaneously provide heating for the passenger compartment. The thermal comfort of the passengers is therefore compromised.

[0004] It is therefore desirable to be able to defrost the heat exchanger recovering heat from the outside air, while continuing to provide heating for the passenger compartment. Summary

[0005] To this end, a method for controlling a thermal conditioning system for a motor vehicle is proposed, the thermal conditioning system 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 fluid accumulation device, - 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 first 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 second branch downstream of the third exchanger and upstream of the fourth connection point to a sixth connection point located on the main loop between the first and second regulators, - a fourth branch connecting a seventh connection point located on the main loop downstream of the first connection point and upstream of the first exchanger to an eighth connection point located on the second branch downstream of the fourth pressure regulator and upstream of the third exchanger, the fourth branch comprising a fifth pressure regulator, the process comprising the steps: (i) provide an initial flow of high-pressure refrigerant at the compressor outlet, (ii) divide the first high-pressure refrigerant flow into a second flow circulating in the main loop and a third flow circulating in the first bypass branch, (iii) divide the second high-pressure refrigerant flow into a fourth flow circulating in the main loop to the first heat exchanger and a fifth flow circulating in the fourth bypass branch, (iv) reduce the high-pressure refrigerant from the first heat exchanger to an intermediate pressure lower than the high pressure and reduce the refrigerant circulating in the fourth bypass branch to the intermediate pressure, (v) circulate the intermediate-pressure refrigerant through the third heat exchanger, (vi) reduce the intermediate-pressure refrigerant from the third heat exchanger to a low pressure below the intermediate pressure, (vii) circulate the low-pressure refrigerant through the second heat exchanger, and in which The third flow circulating in the first bypass branch is expanded to low pressure and joins the low-pressure refrigerant from the second exchanger, the low-pressure refrigerant joining the compressor.

[0006] According to the proposed method, the high-pressure refrigerant transfers heat to the interior airflow via the first heat exchanger, thereby heating the vehicle's passenger compartment. The refrigerant from the third heat exchanger is sufficiently hot to transfer heat as it passes through the second heat exchanger. When the second heat exchanger has accumulated ice, resulting from prior operation in heat pump mode, the heat transferred by the refrigerant melts the accumulated ice. The proposed operating method thus allows the second heat exchanger to be defrosted while continuing to heat the passenger compartment. Thermal comfort is therefore maintained during defrosting phases without the need for an additional heating device such as For example, electric heating. Thermal comfort is thus improved without increasing the cost of the heating and cooling system.

[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 the proposed process, the second exchanger operates as a refrigerant fluid cooler.

[0012] According to one embodiment, the first heat exchanger is configured to exchange heat with the airflow inside the vehicle's passenger compartment.

[0013] 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.

[0014] According to the proposed method: - The refrigerant from the first heat exchanger is expanded by the fourth expansion valve to an intermediate pressure lower than the high pressure. - the refrigerant circulating in the fourth branch of the bypass is expanded by the fifth expansion valve to the intermediate pressure, and - the refrigerant circulating in the third branch of the bypass is expanded by the second expansion valve to a low pressure lower than the intermediate pressure.

[0015] According to one aspect of the proposed control method, the flow rate of refrigerant circulating in the first expansion valve is zero.

[0016] According to one aspect of the proposed control method, the refrigerant fluid from the third exchanger joins the second expansion valve without passing through any other heat exchanger.

[0017] According to one embodiment, the second branch branch includes a sixth regulator disposed between the fourth connection point and the fifth connection point.

[0018] The fifth connection point is located on the second branch of the bypass downstream of the third exchanger and upstream of the sixth regulator.

[0019] According to various aspects of the proposed process: - The first regulator is thus in the closed position. - The second regulator is in the partially open position. - The third regulator is in the partially open position. - The fourth regulator is in the partially open position. - The fifth regulator is in the partially open position. - The sixth regulator is thus in the closed position.

[0020] The opening position of the fourth regulator may differ from the opening position of the fifth regulator. The opening position of the third regulator may differ from the opening position of the second regulator.

[0021] According to the proposed process, the third exchanger can be thermally inactive.

[0022] According to one embodiment, the element of the vehicle's electric drive chain includes an electrical energy storage battery.

[0023] Alternatively or in addition, the element of the vehicle's electric drive chain includes an electric vehicle traction motor.

[0024] 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.

[0025] 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.

[0026] Each regulator is, for example, an electronic regulator.

[0027] The value of the so-called "high pressure" at the outlet of the compressor 7 is, for example, between 80 bars and 120 bars. The value of the so-called "intermediate" pressure, after pressure reduction by the fourth regulator on the one hand, and by the fifth regulator on the other, is lower than the high-pressure value. The intermediate pressure is, for example, between 45 bar and 75 bar. The value of the so-called "low pressure", after expansion by the second and third regulators, is lower than the value of the intermediate pressure. Low pressure, for example, is between 35 bars and 45 bars.

[0028] The flow rate of refrigerant circulating in the refrigerant circuit is equal to the flow rate of refrigerant discharged by the compressor.

[0029] According to an example of an implementation of the proposed method, in which the third heat exchanger is thermally coupled to the element of the vehicle's electric powertrain via a circulating heat transfer fluid in a heat transfer fluid circuit, the flow rate of heat transfer fluid in the third exchanger is below a predetermined threshold.

[0030] For example, the flow rate of heat transfer fluid circulating in the third exchanger is zero.

[0031] In this case, the heat exchange in the third heat exchanger is zero. All the heating power is thus dissipated in the first and second heat exchangers. In other words, the heating power is only sufficient to heat the passenger compartment and defrost the second heat exchanger. The time required to remove the accumulated ice is therefore reduced.

[0032] According to an example of an implementation of the proposed control method, in which the thermal conditioning system includes a movable device configured to vary a cross-section of the passage of the outside air flow to the second exchanger, the passage cross-section being able to vary between a minimum value and a maximum value, the control method comprises the step: - control the mobile device for varying the cross-section of the passage of the outside airflow so that the cross-section is equal to the minimum value.

[0033] In other words, the mobile device can be placed in a position where the flow of outside air reaching the second heat exchanger is minimized. The heat transferred by the refrigerant to the outside air flow at the second heat exchanger is therefore also minimized. Heat losses are reduced, and the removal of ice accumulated on the second heat exchanger is thus accelerated.

[0034] The mobile device for varying the cross-section of the passage of the outside air flow is arranged upstream of the second heat exchanger according to the direction of the outside air flow.

[0035] The mobile device for varying the cross-section of the passage of the outside airflow is movable between a position in which the cross-section of the passage of the outside airflow is maximum and a second position in which the cross-section of the passage of the outside airflow is minimum.

[0036] The minimum passage section can be zero.

[0037] In other words, the mobile device can be in the closed position, and the second exchanger does not receive outside air. All the heat released by the refrigerant can be used to melt the ice deposit.

[0038] The mobile device includes, for example, a set of flaps that can be moved by a control mechanism coupled to an electric motor.

[0039] The proposed control method may include the following steps: - determine the thermal power supplied jointly by the first and second heat exchangers, - control the flow rate of refrigerant circulating in the refrigerant circuit so as to control the thermal power supplied jointly by the first and second exchangers to a first target value.

[0040] The control process may include the following step: - control the compressor rotation speed in order to control the flow of refrigerant circulating in the refrigerant circuit.

[0041] The control process may include the following substeps: - increase the compressor speed to increase the flow rate of refrigerant circulating in the refrigerant circuit, and - reduce the compressor rotation speed in order to decrease the flow of refrigerant circulating in the refrigerant circuit.

[0042] According to an example of implementation of the control method, in which the compressor is an electric compressor, the method may include the steps: - determine an electrical power absorbed by the compressor, - control the rotation speed of the compressor so as to control the electrical power absorbed by the compressor to a second target value.

[0043] The process may include the substep: - determine a value for the adiabatic efficiency of the compressor.

[0044] The second target value is for example equal to the first target value divided by the determined value of an adiabatic efficiency of the compressor.

[0045] The proposed method may include a substep for determining the compressor rotation speed.

[0046] The control process may include the following sub-steps: - reduce the compressor's rotation speed if the electrical power absorbed by the compressor exceeds the second target value. - increase the compressor rotation speed if the electrical power absorbed by the compressor is less than the second target value.

[0047] The third expansion valve allows the temperature of the internal airflow to be adjusted after heating.

[0048] The proposed control method thus comprises the following steps: - receive a temperature setpoint for the indoor airflow exiting the first heat exchanger, - determine a temperature of the indoor airflow at the outlet of the first exchanger, - control an expansion of the refrigerant in the fourth expansion valve so that the determined temperature of the indoor airflow at the outlet of the first exchanger is equal to the temperature setpoint.

[0049] The control process may therefore include the following sub-steps: - reduce the passage cross-section of the fourth expansion valve when the determined temperature of the indoor air flow exiting the first heat exchanger is lower than the temperature setpoint, - increase a passage section of the fourth expansion valve when the determined temperature of the indoor air flow at the outlet of the first exchanger is greater than the temperature setpoint.

[0050] The fifth expansion valve allows the temperature of the intermediate pressure refrigerant fluid formed by mixing the refrigerant fluid from the fourth expansion valve and the refrigerant fluid from the fourth branch of the bypass valve to be adjusted.

[0051] The control process thus comprises the following steps: - receive a temperature setpoint for the refrigerant fluid at the inlet of the third heat exchanger, - determine a temperature of the refrigerant at the outlet of the third exchanger, - control an expansion of the refrigerant in the fifth expansion valve in order to control the temperature of the refrigerant at the inlet of the third exchanger to a third target value.

[0052] The control process comprises the following substeps: - reduce the cross-sectional area of ​​the refrigerant flow through the fifth expansion valve if the temperature of the refrigerant at the outlet of the third heat exchanger is higher than the third target value, - increase the refrigerant flow area through the fifth expansion valve if the refrigerant temperature at the outlet of the third exchanger is below the third target value.

[0053] According to another aspect, the control process comprises the following steps: - determine a value for the pressure of the low-pressure refrigerant fluid, - control a refrigerant expansion in the second expansion valve so as to control the low-pressure refrigerant pressure to a fourth target value.

[0054] The control process comprises the following substeps: - reduce the cross-sectional area of ​​the refrigerant flow through the second expansion valve if the low-pressure refrigerant pressure exceeds the fourth target value. - increase the refrigerant passage cross-section through the second expansion valve if the low-pressure refrigerant pressure is below the fourth target value.

[0055] The third regulator makes it possible in particular to maintain the low pressure above an acceptable minimum value.

[0056] The control process may therefore include the following steps: - determine a value for the pressure of the low-pressure refrigerant fluid, - increase the cross-sectional area of ​​the refrigerant passing through the third expansion valve if the value of the low-pressure refrigerant is less than a predetermined minimum value.

[0057] The third expansion valve also makes it possible to maintain the compression ratio of the compressor below an acceptable maximum value.

[0058] The control process may therefore include the following steps: - determine a value for the pressure of the high-pressure refrigerant fluid, - determine a value for the pressure of the low-pressure refrigerant fluid, - determine a ratio between the pressure value of the high-pressure refrigerant and the pressure value of the low-pressure refrigerant, - increase the cross-sectional area of ​​the refrigerant passing through the third expansion valve if the determined ratio is greater than a predetermined maximum value.

[0059] 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 fluid accumulation device, - 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 first 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 to a fifth connection point located on the second branch downstream of the third interchange and in upstream of the fourth connection point to a sixth connection point located on the main loop between the first regulator and the second regulator, - a fourth branch connecting a seventh connection point located on the main loop downstream of the first connection point and upstream of the first exchanger to an eighth connection point located on the second branch downstream of the fourth regulator and upstream of the third exchanger, the fourth branch comprising a fifth regulator, - an electronic control unit configured to implement the process described above.

[0060] According to one embodiment, the thermal conditioning system 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.

[0061] 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 a compressor inlet.

[0062] The internal exchanger, also called the internal heat exchanger, is configured to allow heat exchange between the refrigerant in the first heat exchange section and the refrigerant in the second heat exchange section.

[0063] According to one embodiment, the thermal conditioning system includes a fifth branch connecting a ninth connection point disposed on the main loop between the first expansion valve and the sixth connection point to a tenth connection point disposed on the main loop between the second connection point and the fourth connection point, the fifth branch successively comprising a seventh expansion valve and a fourth heat exchanger configured to exchange heat with an indoor airflow.

[0064] The fourth exchanger is arranged upstream of the first exchanger according to a direction of flow of the internal airflow.

[0065] When the fifth branch of the bypass is present, the internal exchanger is configured to allow heat exchange between the refrigerant flowing between the ninth connection point and the sixth connection point and the refrigerant flowing downstream of the accumulation device and upstream of a compressor inlet.

[0066] The main loop includes a first shut-off valve disposed between the first connection point and the seventh connection point.

[0067] The main loop includes a second shut-off valve disposed between the second connection point and the fourth connection point.

[0068] The main loop includes a second shut-off valve disposed between the second connection point and the tenth connection point.

[0069] The first shut-off valve is an electrically operated valve. Similarly, the second shut-off valve is an electrically operated valve.

[0070] The refrigerant circuit includes a first one-way valve disposed on the main loop between the first exchanger and the third connection point.

[0071] The first one-way valve is configured to allow refrigerant to flow through the first one-way valve from the first heat exchanger to the third connection point. The first one-way valve is also configured to prevent refrigerant to flow through the first one-way valve from the third connection point to the first heat exchanger.

[0072] The refrigerant circuit includes a second one-way valve disposed on the third branch of the bypass.

[0073] The second one-way valve is configured to allow refrigerant flow through the second one-way valve from the fifth connection point to the sixth connection point and configured to prohibit refrigerant flow through the second one-way valve from the sixth connection point to the fifth connection point.

[0074] The refrigerant circuit includes a third one-way valve disposed on the main loop between the fourth exchanger and the tenth connection point.

[0075] The third one-way valve is configured to allow refrigerant fluid to circulate through the third one-way valve of the fourth exchanger to the sixth connection point.

[0076] The third one-way valve is also configured to prohibit refrigerant fluid circulation through the third one-way valve from the sixth connection point to the fourth exchanger.

[0077] The first one-way valve is, for example, a non-return valve.

[0078] Similarly, the second one-way valve and the third one-way valve can also be a check valve.

[0079] Alternatively, each one-way valve can be an electrically operated valve.

[0080] The disclosure also relates to a computer program stored in memory and configured to implement the process described above. Brief description of the drawings

[0081] Other features, details and advantages will become apparent upon reading the detailed description below, and upon analysis of the accompanying drawings, on which:

[0082] [Fig-1] is a schematic view of a thermal conditioning system according to a first embodiment of the invention,

[0083] [Fig.2] is a schematic view of a thermal conditioning system according to a second embodiment of the invention,

[0084] [Fig.3] is a schematic view illustrating the operation of the system of thermal conditioning of [Fig.2] during the implementation of the proposed process,

[0085] [Fig.4] is a diagram illustrating the operation of the system of thermal conditioning of [Fig.2] during the implementation of the proposed process,

[0086] [Fig.5] is a block diagram of the proposed process. Description of the implementation methods

[0087] 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.

[0088] 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, and then returns to the compression device, possibly after passing through other elements..

[0089] 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.

[0090] When it is specified that a subsystem includes a given element, this does not exclude the presence of other elements in that subsystem.

[0091] The thermal conditioning system 100, which will be described below, comprises an electronic control unit 65 that receives information from various sensors measuring, in particular, the characteristics of the refrigerant at various points in a refrigerant circulation circuit. The electronic control unit 65 also receives instructions from the vehicle occupants, for example, the desired temperature inside the passenger compartment. The electronic control unit 65 can also receive instructions from other electronic subsystems, such as a battery management system for electrical energy storage. The electronic control unit 65 implements control laws to operate various actuators in order to control the thermal conditioning system 100 and execute the received instructions. Control unit 65 can execute software coding the proposed process.

[0092] 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 pass from a low pressure at the inlet 7a to a high pressure at the outlet 7b. After expansion in one or more expansion chambers and circulation in at least part of the circuit, the refrigerant returns to the inlet 7a of the compressor 7 and begins a new thermodynamic cycle.

[0093] 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 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 located on each of these sections. In other words, each connection point is a means of redirecting 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 ensure different operating modes, as will be described later.

[0094] 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.

[0095] 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 refrigerant flow is stopped; that is, the flow rate 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.

[0096] 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, also not shown, is located within the HVAC system to increase the flow rate of the interior airflow Fi if necessary.

[0097] 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 60 of the climate control system 100.

[0098] 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".

[0099] 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.

[0100] A thermal conditioning system 100 for a motor vehicle is shown in [Fig.1]. The thermal conditioning system 100 comprises a refrigerant circuit 10 having 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's passenger compartment, — a refrigerant fluid accumulation device 8. The refrigerant circuit 10 includes 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 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. The refrigerant circuit 10 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 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 includes 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 includes a third branch D connecting a fifth connection point 15 located on the second branch C downstream of the third exchanger 3 and upstream of the fourth connection point 14 to a sixth connection point 16 located on the main loop A between the first expansion valve 31 and the second expansion valve 32. The refrigerant circuit 10 includes a fourth branch E connecting a seventh connection point 17 located on the main loop A downstream of the first connection point 11 and upstream of the first heat exchanger 1 to a eighth connection point 18 located on the second branch of the bypass C downstream of the fourth regulator 34 and upstream of the third exchanger 3. The fourth branch of the bypass E includes a fifth regulator 35. The thermal conditioning system 100 includes an electronic control unit 65 configured to implement the process described above.

[0101] A computer program stored in memory can implement the proposed method. The memory can be integrated into the electronic control unit 65.

[0102] The refrigerant circuit 10 is configured to circulate a refrigerant. The compressor 7 changes the refrigerant 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.

[0103] 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.

[0104] The thermal coupling between the first heat exchanger 1 and the internal airflow Fi can be achieved in different ways.

[0105] According to an example embodiment, schematically illustrated in [Fig.2], the first heat exchanger 1 is configured to exchange heat with the interior airflow Fi to the vehicle's passenger compartment.

[0106] The thermal coupling between the first heat exchanger 1 and the interior airflow Fi is, in this case, said to be direct. Indeed, the interior airflow Fi is in contact with the walls of the heat exchanger 1 through 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.

[0107] According to an alternative embodiment, schematically illustrated in [Fig. 1], 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 includes a heat exchanger IA configured to exchange heat with the interior airflow Fi to the vehicle's passenger compartment.

[0108] The thermal coupling between the first heat exchanger 1 and the internal airflow Fi is then said to be indirect. Indeed, the heat from the refrigerant fluid is dissipated in a heat transfer fluid, and the heat from the heat transfer fluid is in turn dissipated in the internal airflow Fi at the level of the exchanger IA, called the heating radiator. The heat transfer fluid thus allows heat transfer between the refrigerant fluid and the internal airflow Fi. The heat transfer fluid circulating in the circuit 30 is, for example, a mixture of water and glycol. In this embodiment, the IA heater radiator is located in the vehicle's heating, ventilation and / or air conditioning system.

[0109] The second heat exchanger 2 is, for example, located at the front of the vehicle so as to receive the outside airflow Fe directly. The second heat exchanger 2 can be located just behind the vehicle's grille.

[0110] According to the embodiment illustrated in the various figures, 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.

[0111] The heat transfer fluid circuit 40 includes, for example, a circulation pump, not shown. When the pump is activated, the heat transfer fluid circulates in the circuit 40. When the pump is inactive, the heat transfer fluid does not circulate in the circuit 40, and the flow rate of the heat transfer fluid in the circuit 40 is zero. The pump is, for example, an electrically driven pump. The pump is, for example, controlled by the electronic control unit 65.

[0112] 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. The third heat exchanger 3 allows the element 25 of the vehicle's electric powertrain to be heated or cooled. The element 25 of the vehicle's electric powertrain can thus be maintained, or placed, within a preferred temperature range corresponding to its optimal operation.

[0113] The heat transfer fluid circulating in the circuit 40 is, for example, a mixture of water and glycol. In the example shown, circuits 30 and 40 are independent, meaning they are not connected. In other, unshown variations, the two circuits can be connected.

[0114] According to the embodiment illustrated in the various figures, 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 may include an electric vehicle traction motor. Alternatively or in addition, element 25 of the vehicle's electric drive chain may include an electronic control unit for the vehicle's electric traction motor.

[0115] The heat transfer fluid of circuit 40 can, for example, circulate between the elements of the electrical energy storage battery, or inside the electric motor, or the housing of the electric motor's electronic control unit. The heat transfer fluid can thus exchange heat with the battery elements, or the electric motor, or the electric motor's electronic control unit.

[0116] In the illustrated example, the second branch of the bypass C includes a sixth regulator 36 disposed between the fourth connection point 14 and the fifth connection point 15. The fifth connection point 15 is located on the second branch of the bypass C downstream of the third exchanger 3 and upstream of the sixth regulator 36.

[0117] Each regulator 31, ..., 36 is for example an electronic regulator.

[0118] The second embodiment of the thermal conditioning system 100, illustrated in [Fig.2], also differs from the first embodiment by the presence of additional elements in the refrigerant circuit 10.

[0119] According to the second embodiment, the thermal conditioning system 100 comprises 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 fluid downstream of the accumulation device 8 and upstream of an inlet 7a of the compressor 7.

[0120] 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 an inlet 7a of the compressor 7.

[0121] 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. The internal exchanger 6 increases the enthalpy variation of the refrigerant during the thermodynamic cycle and thus improves the thermal performance of system 100.

[0122] According to the second embodiment illustrated in [Fig. 2], the thermal conditioning system 100 comprises a fifth branch F connecting a ninth connection point 19 arranged on the main loop A between the first expansion valve 31 and the sixth connection point 16 to a tenth connection point 20 arranged on the main loop A between the second connection point 12 and the fourth connection point 14. The fifth branch F includes successively a seventh expansion valve 37 and a fourth heat exchanger 4 configured to exchange heat with an internal airflow Fi.

[0123] The fourth exchanger 4, called the passenger compartment evaporator, allows the interior airflow Fi and thus the passenger compartment of the vehicle to be cooled. The fourth heat exchanger 4 is located in the vehicle's heating, ventilation and / or air conditioning system. According to the second embodiment, the fourth heat exchanger 4 is arranged upstream of the first heat exchanger 1 in the direction of the internal airflow Fi. According to the first embodiment, the fourth heat exchanger 4 is arranged upstream of the heat exchanger IA in the direction of the internal airflow Fi.

[0124] The presence of the fifth branch F is independent of the presence of the internal exchanger 6. In other words, the thermal conditioning system 100 may include a fifth branch F but not include an internal exchanger 6, and vice versa. Similarly, the method of achieving thermal coupling between the first exchanger 1 and the internal airflow Fi is independent of the presence of the fifth branch of bypass F, as well as the presence of the internal exchanger 6.

[0125] When the fifth branch F is present, the internal exchanger 6 is configured to allow heat exchange between: - the refrigerant circulating between the ninth connection point 19 and the sixth connection point 16, and - the refrigerant fluid circulating downstream of the accumulation device 8 and upstream of an inlet 7a of the compressor 7.

[0126] 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.

[0127] The main loop A includes a first shut-off valve 41 disposed between the first connection point 11 and the seventh connection point 17.

[0128] The main loop A also includes a second shut-off valve 42 located downstream of the second exchanger 2.

[0129] According to the first embodiment, in which the refrigerant circuit 10 does not include a fifth branch F, the main loop A comprises a second shut-off valve 42 arranged between the second connection point 12 and the fourth connection point 14.

[0130] According to the second embodiment, in which the fifth branch F is present on the refrigerant circuit 10, the main loop A includes a second shut-off valve 42 disposed between the second connection point 12 and the tenth connection point 20.

[0131] The first shut-off valve 41 is an electrically operated valve. Similarly, the second shut-off valve 42 is an electrically operated valve. Each shut-off valve 41, 42 is for example controlled by the electronic control unit 65.

[0132] 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.

[0133] The first one-way valve 43 is configured to allow refrigerant fluid to circulate through the first one-way valve 43 from the first heat exchanger 1 to the third connection point 13. The first one-way valve 43 is also configured to prohibit refrigerant fluid to circulate through the first one-way valve 43 from the third connection point 13 to the first heat exchanger 1.

[0134] The refrigerant fluid circuit 10 includes a second one-way valve 44 disposed on the third branch branch D.

[0135] The second one-way valve 44 is configured to allow refrigerant fluid to circulate through the second one-way valve 44 from the fifth connection point 15 to the sixth connection point 16 and configured to prohibit refrigerant fluid to circulate through the second one-way valve 44 from the sixth connection point 16 to the fifth connection point 15.

[0136] According to the second embodiment, 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 tenth connection point 20.

[0137] The third one-way valve 45 is configured to allow refrigerant fluid to circulate through the third one-way valve 45 from the fourth exchanger 4 to the sixth connection point 16. The third one-way valve 45 is also configured to prohibit refrigerant flow through the third one-way valve 45 from the sixth connection point 16 to the fourth exchanger 4.

[0138] The first one-way valve 43 is, for example, a non-return valve. Similarly, the second one-way valve 44 and the third one-way valve 45 can also be a check valve. According to variants not shown, each one-way valve 43, 44, 45 can be an electrically operated valve.

[0139] The thermal conditioning system 100 can operate in several operating modes.

[0140] A particular operating mode is, for example, a so-called "heat pump" mode. In this operating mode, the high-pressure refrigerant discharged by the compressor 7 releases heat to the indoor airflow Fi at the first heat exchanger 1, then circulates through the first expansion valve 31, through the second expansion valve 32 where it changes to low pressure, then circulates through the second heat exchanger 2. The low-pressure refrigerant evaporates in the second heat exchanger, receiving heat from the outside airflow, then circulates through the main loop A to the fourth connection point 14, through the accumulator 8, and returns to the inlet 7a of the compressor 7, thus closing the thermodynamic cycle. In this operating mode, the heat extracted from the outside airflow Fe contributes to heating the inside airflow Fi. The outside airflow Fe is cooled by the heat exchange with the refrigerant. When the ambient temperature is near 0°C or below, the water vapor in the outside air can freeze and accumulate on the second heat exchanger 2. As ice builds up, heat exchange becomes increasingly impaired, and operation in heat pump mode may no longer be possible. The second heat exchanger 2 must then be defrosted.

[0141] The proposed method, when implemented, corresponds to another particular operating mode of the thermal conditioning system 100.

[0142] A method for controlling a thermal conditioning system for a motor vehicle is proposed. The thermal conditioning system 100 comprises a refrigerant circuit 10 including: - 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's passenger compartment, — a refrigerant fluid storage device 8, - 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 first expansion valve 31 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 located on the second branch branch C downstream of the third exchanger 3 and upstream of the fourth connection point 14 to a sixth connection point 16 located on the main loop A between the first regulator 31 and the second regulator 32, - a fourth branch E connecting a seventh connection point 17 located on the main loop A downstream of the first connection point 11 and upstream of the first exchanger 1 to an eighth connection point 18 located on the second branch C downstream of the fourth regulator 34 and upstream of the third exchanger 3, the fourth branch E comprising a fifth regulator 35. The process involves the following steps: (i) provide a first flow Q1 of high-pressure refrigerant HP at the outlet of compressor 7, (ii) divide the first flow Q1 of high-pressure refrigerant HP into a second flow Q2 circulating in the main loop A and a third flow Q3 circulating in the first branch of the bypass B, (iii) divide the second flow Q2 of high-pressure refrigerant into a fourth flow Q4 circulating in the main loop A towards the first exchanger 1 and a fifth flow Q5 circulating in the fourth bypass branch E, (iv) reduce the high-pressure refrigerant from the first heat exchanger 1 to an intermediate pressure IP lower than the high pressure HP and reduce the refrigerant circulating in the fourth bypass branch E to the intermediate pressure IP, (v) circulate the intermediate-pressure refrigerant through the third heat exchanger 3, (vi) reduce the intermediate pressure refrigerant from the third heat exchanger 3 to a low pressure BP lower than the intermediate pressure, (vii) circulate the low pressure refrigerant through the second heat exchanger 2, and the third flow Q3 circulating in the first branch of bypass B is expanded to the low pressure BP and joins the low pressure refrigerant BP coming from the second exchanger 2, the low pressure refrigerant BP joining the compressor 7.

[0143] According to the proposed process, the high-pressure refrigerant transfers heat to the interior airflow Fi via the first heat exchanger 1, thereby heating the vehicle's passenger compartment. After circulating through the third heat exchanger 3, the refrigerant from the third heat exchanger 3 is still sufficiently hot to transfer heat as it passes through the second heat exchanger 2. When the second heat exchanger 2 has accumulated ice, resulting from prior operation in heat pump mode, the heat transferred by the refrigerant melts the ice accumulated on the second heat exchanger 2. The refrigerant circulating in the first branch of the bypass B creates a gaseous mixture downstream of the second connection point 12, thus completing the thermodynamic cycle. The proposed operating mode thus allows the second exchanger 2 to be defrosted while continuing to provide heating for the passenger compartment via the first exchanger 1. No additional heating device, such as electric heating, is necessary to maintain thermal comfort. Compared to conventional solutions, thermal comfort is improved without adding any components that would increase the cost, size, or weight of the heating and cooling system.

[0144] The flow rate of refrigerant circulating in the refrigerant circuit 10 is equal to the flow rate of refrigerant discharged by the compressor 7.

[0145] In steady state, the time variation of the mass of refrigerant in a heat exchanger is zero, and the flow rate of refrigerant downstream of a heat exchanger is equal to the flow rate of refrigerant upstream of this heat exchanger. Similarly, there is no accumulation of refrigerant in an expansion valve, and the flow rate of refrigerant downstream of an expansion valve is equal to the flow rate upstream of that expansion valve. Thus, in steady state the refrigerant flow rate at the outlet of the first heat exchanger 1 is equal to the refrigerant flow rate at the inlet of the first heat exchanger 1. Similarly, the refrigerant flow rate circulating in the fourth branch of bypass E downstream of the fifth expansion valve 35 is equal to the refrigerant flow rate circulating in the fourth branch of bypass E upstream of the fifth expansion valve 35. In steady state, the flow rate of refrigerant drawn in by compressor 7 is identical to the flow rate Q1 discharged by compressor 7.

[0146] Figure 3 illustrates the circulation of the refrigerant in circuit 10 when the proposed process is implemented. Figure 3 illustrates steady-state operation. In this figure, the portions of circuit 10 in which refrigerant flows are shown as thick solid lines, while the portions in which refrigerant does not flow are shown as thin dashed lines. The different arrows indicate the direction of refrigerant flow in the various portions of the refrigerant circuit 10.

[0147] The refrigerant fluid discharged at high pressure HP by the compressor 7, equal to the first flow Q1, divides at the first connection point 11. Part of the divided flow circulates in the main loop A, passes through the first shut-off valve 41 which is in the open position and reaches the seventh connection point 17. This part forms the second flow Q2. The other part of the divided flow, complementary to the second flow Q2, circulates in the first branch of bypass B towards the third regulator 33. This other part forms the third flow Q3.

[0148] The second flow Q2 is divided at the seventh connection point 17. Part of the second flow Q2 circulates in the main loop A towards the first exchanger 1. This part forms the fourth flow Q4. The other part of the divided flow, complementary to the fourth flow Q4, circulates in the fourth branch of bypass E towards the fifth regulator 35. This other part forms the fifth flow Q5. After passing through the first exchanger 1, the refrigerant reaches the third connection point 13, then flows through the second branch C towards the fourth expansion valve 34. Passing through the fourth expansion valve 34, the refrigerant is expanded to the so-called intermediate pressure IP, and reaches the eighth connection point 18. The refrigerant circulating in the fourth branch E passes through the fifth expansion valve 35, is expanded to the intermediate pressure, and rejoins at the eighth connection point 18 the refrigerant coming from the outlet 34b of the fourth expansion valve 34. The combination of the two refrigerant flow rates forms the second flow rate Q2, in steady state.

[0149] The second flow Q2 then circulates in the third heat exchanger 3, reaches the fifth connection point 15, circulates in the third branch line D, reaches the sixth connection point 16, and then circulates in the second expansion valve 32 where it is reduced to a low pressure BP. The low-pressure refrigerant at the outlet of the fourth expansion valve 34 circulates in the second heat exchanger 2, and reaches the second connection point 12.

[0150] The refrigerant circulating in the first branch of the bypass B is expanded to the low pressure BP by the third expansion valve 33, and joins at the second connection point 12 the refrigerant coming from the second exchanger 2. The union of the two refrigerant flow rates forms the first flow rate Ql, always in steady state. The first flow Ql of low pressure refrigerant BP circulates in the main loop A, passes through the second shut-off valve 42 which is in the open position, then the tenth connection point 20, the fourth connection point 14, the accumulator 8, the second heat exchange section 6b of the internal exchanger 6, and returns to the inlet 7a of the compressor 7.

[0151] Figure 4 schematically illustrates the value of the refrigerant fluid pressure at different locations in the refrigerant circuit 10. On the vertical axis, the value designated by the symbol HP represents the high pressure, the value designated by the symbol BP represents the low pressure, and the value designated by the symbol IP represents the intermediate pressure. The diagram is not to scale and is only intended to differentiate the three pressure levels. On the horizontal axis, the symbol P34a designates the inlet pressure 34a of the fourth regulator 34. The symbol P34b designates the outlet pressure 34b of the fourth regulator 34, therefore after a possible expansion in the fourth regulator 34. Similarly, the symbol P36a designates the inlet pressure 36a of the sixth regulator 36, and the symbol P36b designates the outlet pressure 36b of the sixth regulator 36. The symbol P35a designates the inlet pressure 35a of the fifth regulator 35. The symbol P35b designates the outlet pressure 35b of the fifth regulator 35.

[0152] According to the proposed process, the first exchanger 1 operates as a refrigerant fluid cooler. In other words, the refrigerant releases heat as it passes through the first exchanger 1. According to the proposed process, the second exchanger 2 operates as a refrigerant fluid cooler. As with the first exchanger 1, the refrigerant gives off heat as it passes through the second exchanger 2.

[0153] According to the proposed method: - the refrigerant from the first heat exchanger 1 is expanded by the fourth expansion valve 34 to an intermediate pressure IP lower than the high pressure HP, - the refrigerant circulating in the fourth bypass branch E is expanded by the fifth expansion valve 35 to the intermediate pressure IP, and - the refrigerant circulating in the third branch of the bypass D is expanded by the second expansion valve 32 to a low pressure BP lower than the intermediate pressure IP.

[0154] The value of the HP pressure, referred to as "high pressure", at the outlet of the compressor 7, is for example between 80 bar and 120 bar. The value of the so-called "intermediate" IP pressure, after pressure reduction by the fourth regulator 34 on the one hand, and by the fifth regulator 35 on the other, is lower than the value of the high pressure HP. The intermediate IP pressure is, for example, between 45 bar and 75 bar. The value of the so-called "low pressure" BP pressure, after expansion by the second regulator 32 and the third regulator 33, is less than the value of the intermediate pressure. Low pressure, for example, is between 35 bars and 45 bars.

[0155] The refrigerant fluid from the third exchanger 3 joins the second expansion valve 32 without passing through any other heat exchanger.

[0156] The flow rate of refrigerant circulating in the first expansion valve 31 is zero. The flow rate of refrigerant circulating in the fourth exchanger 4 is zero. The flow rate of refrigerant circulating in the first heat exchange section 6a of the internal exchanger 6 is zero. The flow rate of refrigerant circulating in the second branch of bypass C between the fifth connection point 15 and the fourth connection point 14 is zero.

[0157] According to various aspects of the proposed process: - The first regulator 31 is thus in the closed position. The flow rate of refrigerant circulating in the main loop A between the third connection point 13 and the sixth connection point 16 is zero. - The second regulator 32 is in the partially open position. - The third regulator 33 is in the partially open position. - The fourth regulator 34 is in the partially open position. - The fifth regulator 35 is in the partially open position. - The sixth regulator 36 is thus in the closed position. - The seventh regulator 37 is in the closed position.

[0158] The opening position of the fourth regulator 34 may differ from the opening position of the fifth regulator 35. The opening position of the third regulator 33 may differ from the opening position of the second regulator 32.

[0159] According to the proposed method, the third heat exchanger 3 can be thermally inactive.

[0160] According to an example of an implementation of the proposed method, in which the third heat exchanger 3 is thermally coupled with the element 25 of the vehicle's electric powertrain via a heat transfer fluid that can circulate in a heat transfer fluid circuit 40, the flow rate QL of heat transfer fluid in the third heat exchanger 3 is less than a predetermined threshold.

[0161] For example, the flow rate QL of heat transfer fluid circulating in the third exchanger 3 is zero. In other words, the flow rate QL of heat transfer fluid circulating in the third exchanger 3 is negligible, and preferably zero.

[0162] When the flow rate QL of heat transfer fluid circulating in the third exchanger 3 is zero, the heat exchange in the third exchanger 3 is zero. All the heating power is thus dissipated at the level of the first heat exchanger 1 and the second heat exchanger 2. In other words, the heating power only allows heating the passenger compartment and defrosting the second heat exchanger 2. The time required to eliminate the accumulated ice is therefore reduced compared to an operating mode in which heating of element 25 is simultaneously ensured at the level of the third heat exchanger 3.

[0163] We will now describe different aspects of the control methods used when the proposed process is implemented.

[0164] According to the example of implementation of the control method illustrated in Figures 2 and 3, the thermal conditioning system 100 includes a movable device 50 configured to vary a passage section of the outside air flow Fe to the second exchanger 2. The cross-section can vary between a minimum value and a maximum value. The control process includes the following step: - control the movable device 50 for varying the cross-sectional area of ​​the outside air flow Fe so that the cross-sectional area is equal to the minimum value.

[0165] In other words, the movable device 50 can be placed in a position in which the outside air flow Fe reaching the second heat exchanger 2 is minimized. The heat given off by the refrigerant to the outside airflow Fe, at the level of the The second heat exchanger 2 is therefore also minimized. Heat losses are reduced, and the removal of ice accumulated on the second heat exchanger 2 is thus accelerated.

[0166] The mobile device 50 is an active grille shutter. The mobile device 50 for varying the cross-section of the passage of the outside air flow Fe is arranged upstream of the second heat exchanger 2 according to the direction of the outside air flow Fe.

[0167] The mobile device 50 for varying the cross-section of the passage of the outside airflow Fe is movable between a position PI in which the cross-section of the passage of the outside airflow Fe is maximum and a second position P2 in which the cross-section of the passage of the outside airflow Fe is minimum. The minimum passage section can be zero.

[0168] In other words, the mobile device 50 can be in the closed position, and the second heat exchanger 2 does not receive outside air. All the heat released by the refrigerant can be used to melt the ice deposit accumulated on the second heat exchanger 2.

[0169] The mobile device 50 includes, for example, a set of flaps that can be moved by a control mechanism coupled to an electric motor.

[0170] For example, a set of substantially flat flaps can, for example, pivot so that their orientation varies between a position PI in which the plane of the flaps is substantially parallel to the airflow and a position P2 in which the plane of the flaps is substantially perpendicular to the airflow. Figure [Fig.2] schematically illustrates the mobile device 50 in the first position PI in which the external airflow passage cross Fe is maximum. Figure [Fig.3] schematically illustrates the mobile device 50 in the second position P2 in which the external airflow passage cross-section Fe is minimal.

[0171] The proposed control method may include the following steps: - determine a thermal power Pw supplied jointly by the first exchanger 1 and the second exchanger 2, - control the flow rate Q of refrigerant circulating in the refrigerant circuit 10 so as to control at a first target value the thermal power Pw supplied jointly by the first exchanger 1 and the second exchanger 2.

[0172] The inspection process may include the step: - control the rotation speed of compressor 7 in order to control the flow of refrigerant circulating in the refrigerant circuit 10.

[0173] The control process may include the following substeps: - increase the rotational speed of compressor 7 in order to increase the flow rate Q of refrigerant circulating in the refrigerant circuit 10, and - reduce the rotation speed of compressor 7 so as to decrease the flow rate Q of refrigerant circulating in the refrigerant circuit 10.

[0174] According to an example of implementation of the control method, in which the compressor 7 is an electric compressor, the method may include the steps: - determine an electrical power Pe absorbed by the compressor 7, - control the rotation speed N of the compressor 7 so as to control the electrical power Pe absorbed by the compressor 7 to a second target value.

[0175] The process may include the substep: - determine a value for the adiabatic efficiency of compressor 7.

[0176] The second target value is for example equal to the first target value divided by the determined value of an adiabatic efficiency of the compressor 7. In other words, by determining at a given instant the electrical power absorbed by the compressor 7 and at the same instant the value of the adiabatic efficiency of the compressor 7, the thermal power received by the refrigerant fluid can be determined.

[0177] The electrical power absorbed by the electric motor of the compressor 7 is determined, for example, from a measurement of the intensity of the electric current and from the control voltage of the electric motor. The adiabatic efficiency of compressor 7 is, for example, determined by a map that takes into account the operating conditions of compressor 7. Other parameters can be taken into account, such as the flow rate delivered by compressor 7.

[0178] The proposed method includes a substep for determining the rotational speed of the compressor 7. The rotational speed can, for example, be determined from the time evolution of the signal delivered by a position sensor determining the angular position of the electric motor's rotor.

[0179] The electrical power absorbed by the compressor 7 is an increasing function of the rotational speed of the compressor 7.

[0180] The control process thus comprises the following sub-steps: - decrease the rotation speed N of compressor 7 if the electrical power Pe absorbed by compressor 7 is greater than the second target value, - increase the rotation speed N of compressor 7 if the electrical power Pe absorbed by compressor 7 is less than the second target value.

[0181] The expansion rate achieved by the fourth expansion valve 34 allows the temperature of the internal airflow Fi to be adjusted after heating.

[0182] 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 an expansion of the refrigerant fluid in the fourth expansion valve 34 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.

[0183] The control process comprises the following substeps: - decrease a passage section of the fourth expansion valve 34 when the determined temperature Tl of the indoor air flow Fi at the outlet of the first exchanger 1 is lower than the temperature setpoint Tc_l, - increase a passage section of the fourth expansion valve 34 when the determined temperature Tl of the indoor air flow Fi at the outlet of the first exchanger 1 is greater than the temperature setpoint Tc_l.

[0184] The fifth expansion valve 35 allows the temperature of the intermediate pressure refrigerant fluid formed by the mixture of the refrigerant fluid from the fourth expansion valve 34 and the refrigerant fluid from the fourth branch of the bypass E to be adjusted.

[0185] The control procedure thus comprises the following steps: - receive a temperature setpoint TRc_3 of the refrigerant fluid at the inlet of the third heat exchanger 3, - determine a TR3 temperature of the refrigerant fluid at the outlet of the third heat exchanger 3, - control a refrigerant expansion in the fifth expansion valve 35 so as to control the temperature TR3 of the refrigerant at the inlet of the third exchanger 3 to a third target value.

[0186] The control process comprises the following substeps: - reduce the cross-sectional area of ​​the refrigerant flow through the fifth expansion valve 35 if the temperature TR3 of the refrigerant at the outlet of the third heat exchanger 3 is greater than the third target value, - increase a cross-section of the refrigerant passing through the fifth expansion valve 35 if the temperature TR3 of the refrigerant at the outlet of the third exchanger 3 is less than the third target value.

[0187] The second pressure regulator 32 allows the pressure level in the second exchanger 2 to be adjusted.

[0188] The control procedure thus comprises the following steps: - determine a value of the pressure P2 of the low-pressure refrigerant, - control an expansion of the refrigerant in the second expansion valve 32 so as to control the pressure P2 of the low-pressure refrigerant to a fourth target value.

[0189] The control process comprises the following substeps: - reduce the cross-sectional area of ​​the refrigerant flow through the second expansion valve 32 if the pressure P2 of the low-pressure refrigerant is greater than the fourth target value, - increase a cross-section of the refrigerant passing through the second expansion valve 32 if the pressure P2 of the low-pressure refrigerant is less than the fourth target value.

[0190] The third regulator 33 makes it possible in particular to maintain the low pressure above an acceptable minimum value.

[0191] The control procedure thus comprises the following steps: - determine a value of the pressure P2 of the low-pressure refrigerant, - increase a passage cross-section of the refrigerant through the third expansion valve 33 if the value of the pressure P2 of the low-pressure refrigerant is less than a predetermined minimum value.

[0192] The third expansion valve 33 also allows the compressor compression ratio to be kept below an acceptable maximum value.

[0193] The control process may therefore include the following steps: - determine a value for the PI pressure of the high-pressure refrigerant, - determine a value for the pressure P2 of the low-pressure refrigerant fluid, - determine a ratio between the value of the pressure PI of the high-pressure refrigerant and the value of the pressure P2 of the low-pressure refrigerant, - increase a passage area of ​​the refrigerant through the third expansion valve 33 if the determined ratio is greater than a predetermined maximum value.

[0194] Increasing the cross-sectional area of ​​the refrigerant in the third expansion valve reduces the compression ratio required to achieve the desired operating point. This limits the mechanical stresses experienced by the compressor 7.

Claims

1. Demands Method for controlling a thermal conditioning system for a motor vehicle, the thermal conditioning system (100) comprising a refrigerant circuit (10) including: - a main loop (A) comprising successively according to the direction of circulation of the refrigerant: — a compressor (7), — a first heat exchanger (1) thermally coupled with an interior airflow (Fi) to a passenger compartment of the vehicle, — 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 passenger compartment of the vehicle, — a refrigerant accumulation device (8),- 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 branch (D) connecting a fifth connection point (15) located on the second branch branch (C) downstream of the third exchanger (3) and upstream of the fourth connection point (14) to a sixth connection point (16) located on the main loop (A) between the first regulator (31) and the second regulator (32),

2. - a fourth branch (E) connecting a seventh connection point (17) located on the main loop (A) downstream of the first connection point (11) and upstream of the first heat exchanger (1) to an eighth connection point (18) located on the second branch (C) downstream of the fourth pressure regulator (34) and upstream of the third heat exchanger (3), the fourth branch (E) comprising a fifth pressure regulator (35), the process comprising the steps: (i) provide a first flow rate (Ql) of high-pressure (HP) refrigerant at the outlet of the compressor (7), (ii) divide the first flow (Ql) of high-pressure (HP) refrigerant into a second flow (Q2) circulating in the main loop (A) and a third flow (Q3) circulating in the first bypass branch (B), (iii) divide the second flow (Q2) of high-pressure refrigerant into a fourth flow (Q4) circulating in the main loop (A) to the first heat exchanger (1) and a fifth flow (Q5) circulating in the fourth bypass branch (E), (iv) reduce the high-pressure refrigerant from the first heat exchanger (1) to an intermediate pressure (IP) lower than the high pressure (HP) and reduce the refrigerant circulating in the fourth bypass branch (E) to the intermediate pressure (IP), (v) circulate the intermediate-pressure refrigerant fluid through the third heat exchanger (3), (vi) reduce the intermediate pressure refrigerant from the third heat exchanger (3) to a low pressure (LP) lower than the intermediate pressure, (vii) circulate the low-pressure refrigerant fluid in the second heat exchanger (2), and in which the third flow (Q3) circulating in the first bypass branch (B) is expanded to the low pressure (LP) and joins the low pressure refrigerant from the second exchanger (2), the low pressure refrigerant (LP) joining the compressor (7). Method according to claim 1, wherein: - the refrigerant from the first exchanger (1) is expanded by the fourth expansion valve (34) to an intermediate pressure lower than the high pressure, - the refrigerant circulating in the fourth branch of the bypass (E) is expanded by the fifth expansion valve (35) to the intermediate pressure, and - the refrigerant circulating in the third branch of the bypass (D) is expanded by the second expansion valve (32) to a low pressure lower than the intermediate pressure.

3. A method according to claim 1 or 2, wherein the third heat exchanger (3) is thermally coupled with the element (25) of the vehicle's electric drive chain via a heat transfer fluid that can circulate in a heat transfer fluid circuit (40), and wherein the flow rate (QL) of heat transfer fluid in the third exchanger (3) is less than a predetermined threshold, or even zero.

4. A control method according to any one of the preceding claims, wherein the thermal conditioning system (100) comprises a movable device (50) configured to vary a passage cross-section of the outside airflow (Fe) to the second exchanger (2), the passage cross-section being able to vary between a minimum value and a maximum value, the control method comprising the step: - controlling the movable device (50) for varying the passage cross-section of the outside airflow (Fe) so that the passage cross-section is equal to the minimum value.

5. A control method according to any one of the preceding claims, comprising the steps: - determining a thermal power (Pw) supplied jointly by the first exchanger (1) and the second exchanger (2), - controlling the flow rate (Q) of refrigerant circulating in the refrigerant circuit (10) so as to control at a first target value the thermal power (Pw) supplied jointly by the first exchanger (1) and the second exchanger (2).

6. A control method according to any one of the preceding claims, wherein the compressor (7) is an electric compressor, the method comprising the steps: - determine an electrical power (Pe) absorbed by the compressor (7), - control the rotation speed (N) of the compressor (7) so as to control the electrical power (Pe) absorbed by the compressor (7) to a second target value.

7. A control method according to any one of the preceding claims, comprising the steps: - receiving a temperature setpoint (Tc_l) of the indoor airflow (Fi) at the outlet of the first exchanger (1), - determining a temperature (Tl) of the indoor airflow (Fi) at the outlet of the first exchanger (1), - controlling an expansion of the refrigerant fluid in the fourth expansion valve (34) 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).

8. A control method according to any one of the preceding claims, comprising the steps: - receiving a temperature setpoint (TRc_3) of the refrigerant at the inlet of the third exchanger (3), - determining a temperature (TR3) of the refrigerant at the outlet of the third exchanger (3), - controlling an expansion of the refrigerant in the fifth expansion valve (35) so as to control the temperature (TR3) of the refrigerant at the inlet of the third exchanger (3) to a third target value.

9. A control method according to any one of the preceding claims, comprising the steps: - determining a value of the pressure (P2) of the low-pressure refrigerant, - controlling an expansion of the refrigerant in the second expansion valve (32) so as to control the pressure (P2) of the low-pressure refrigerant to a fourth target value.

10. A control method according to any one of the preceding claims, comprising the steps: - determining a value of the pressure (P2) of the low-pressure refrigerant, - increasing a cross-sectional area of ​​the refrigerant passage through the third expansion valve (33) if the value of the pressure (P2) of the fluid Low refrigerant pressure is below a predetermined minimum value.

11. A control method according to any one of the preceding claims, comprising the steps: - determining a value of the pressure (PI) of the high-pressure refrigerant, - determining a value of the pressure (P2) of the low-pressure refrigerant, - determining a ratio between the value of the pressure (PI) of the high-pressure refrigerant and the value of the pressure (P2) of the low-pressure refrigerant, - increasing a cross-section of the refrigerant through the third expansion valve (33) if the determined ratio is greater than a predetermined maximum value.

12. Thermal conditioning system (100) for a motor vehicle, comprising a refrigerant circuit (10) including: - 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),- 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 loop, main (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 (D) connecting a fifth connection point (15) disposed on the second branch (C) downstream of the third exchanger (3) and upstream of the fourth connection point (14) to a sixth connection point (16) disposed on the main loop (A) between the first expansion valve (31) and the second expansion valve (32),- a fourth branch (E) connecting a seventh connection point (17) located on the main loop (A) downstream of the first connection point (11) and upstream of the first heat exchanger (1) to an eighth connection point (18) located on the second branch (C) downstream of the fourth pressure regulator (34) and upstream of the third heat exchanger (3), the fourth branch (E) comprising a fifth pressure regulator (35), - an electronic control unit (65) configured to implement the method according to any one of the preceding claims.

13. Thermal conditioning system (100) according to the preceding claim, comprising: - 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 storage device (8) and upstream of an inlet (7a) of the compressor (7), - a fifth branch (F) connecting a ninth connection point (19) disposed on the main loop (A) between the first expansion valve (31) and the sixth connection point (16) to a tenth connection point (20) disposed on the main loop (A) between the second connection point (12) and the fourth connection point (14), the fifth branch (F) comprising successively a seventh expansion valve (37) and a fourth heat exchanger (4) configured to exchange heat with an internal airflow (Fi).

14. Computer program stored in memory and configured to implement the method according to any one of claims 1 to 11.

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