Method for controlling a thermal conditioning system for a motor vehicle

Abstract

The invention relates to a method for controlling a thermal conditioning system for a motor vehicle, comprising a refrigerant circuit (10) including: - a main loop (A) comprising: - 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 second bypass branch (C) including a third heat exchanger (3), the method comprising the steps: (ii) circulating refrigerant at high pressure through the first heat exchanger (1) and through the first bypass branch (B), (iv) reducing at least a portion of the refrigerant from the first heat exchanger (1) to a low pressure, and circulating it through the second heat exchanger (2),(vi) expand the refrigerant from the first branch (B) and mix it with the refrigerant from the second heat exchanger (2). Figure from the abstract: Figure 5,

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 rate provided by each of the expansion devices upstream of these exchangers. Possible operating modes include 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 is expanded 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 use electric heating, which increases energy consumption.

[0004] It is therefore desirable to be able to heat the passenger compartment of the vehicle while avoiding causing frosting of the heat exchanger recovering heat from the outside air. 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, the main loop comprising an internal heat exchanger configured to allow heat exchange between the refrigerant circulating between the first and second expansion valves and the refrigerant circulating downstream of the accumulation device and upstream of a compressor inlet, - 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 successively comprising 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 to a seventh connection point arranged on the main loop downstream of the first connection point and upstream of the first exchanger to an eighth connection point arranged 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) circulate at least a portion of the second high-pressure refrigerant flow through the first heat exchanger, (iv) reduce at least a portion of the high-pressure refrigerant from the first heat exchanger to a low pressure, (v) circulate the low-pressure refrigerant through the second exchanger, (vi) reduce the third flow to low pressure so that the third flow joins the refrigerant from the second exchanger to form the first flow, the first low-pressure refrigerant flow joining the compressor.

[0006] In the proposed process, the thermal energy extracted from the outside airflow at the second heat exchanger contributes to heating the vehicle passenger compartment at the first heat exchanger. The flow rate of refrigerant circulating in the first bypass branch allows the thermodynamic cycle to be completed while limiting the amount of heat extracted from the outside airflow. The risk of icing of the second heat exchanger is thus reduced, without limiting the thermal power supplied to the passenger compartment.

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

[0011] According to one embodiment, the first heat exchanger is configured to exchange heat with a heat transfer fluid circulating in a 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.

[0012] According to the proposed process, the first exchanger operates as a refrigerant fluid cooler.

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

[0014] According to the proposed process, the third exchanger can operate as a refrigerant fluid cooler.

[0015] The third heat exchanger allows the electric powertrain element of the vehicle to be heated. The electric powertrain element of the vehicle can thus be maintained, or placed, within a preferred temperature range corresponding to the optimal operation of that element.

[0016] According to one embodiment, the element of the vehicle's electric powertrain includes an electrical energy storage battery.

[0017] Alternatively or in addition, the element of the vehicle's electric drive chain includes an electric vehicle traction motor.

[0018] 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.

[0019] 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.

[0020] According to one embodiment, the second branch branch includes a sixth regulator disposed between the fourth connection point and the fifth connection point.

[0021] Each regulator is, for example, an electronic regulator.

[0022] 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. 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.

[0023] According to a first example of implementation of the process, the refrigerant fluid from the first exchanger circulates in the first expansion valve where it passes at intermediate pressure, in the internal exchanger, then in the second expansion valve where it passes at low pressure. According to this first implementation example, the refrigerant flow rate circulating in the second heat exchanger is equal to the refrigerant flow rate circulating in the first interchange.

[0024] The value of the so-called "high pressure" at the outlet of the compressor 7 is, for example, between 40 bars and 130 bars. The value of the so-called "intermediate" pressure, after expansion for example by the first regulator 31, is lower than the value of the high pressure. The intermediate pressure is, for example, between 20 bar and 70 bar. The value of the so-called "low pressure", after expansion for example in the second regulator 32, is less than the value of the intermediate pressure. Low pressure, for example, is between 10 bars and 40 bars.

[0025] According to this first example of implementation of the process: - The first regulator is in the partially open 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 closed position. - The fifth regulator is in the closed position. - The sixth regulator is in the closed position.

[0026] According to a second example of implementation of the process, the second flow of high-pressure refrigerant circulates in the first exchanger and is divided into a first part circulating in the main loop and a second part circulating in the second bypass branch. The refrigerant circulating in the second branch of the bypass flows into the fourth expansion valve where it passes through a low-pressure stage. and the low-pressure refrigerant from the third exchanger joins the low-pressure refrigerant from the second exchanger and the first bypass branch.

[0027] In this second embodiment, the low-pressure refrigerant circulating in the third heat exchanger recovers the heat dissipated by the thermal losses of the vehicle's electric powertrain element. Energy efficiency is thus improved.

[0028] According to this second example of implementation of the process: - The first regulator is in the partially open 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 closed position. - The sixth regulator is in the fully open position.

[0029] According to a third embodiment of the process, the second flow of high-pressure refrigerant circulating in the main loop splits into a the first part circulating in the first exchanger then in the second branch, and a second part complementary to the first part circulating in the fourth branch, the first part and the second part joining upstream of the third exchanger and forming the second flow, the second flow circulating successively in the third exchanger, in the second branch, in the third branch, in the second pressure regulator, in the second exchanger, the second flow joining the third flow and forming the first flow, the first flow joining the compressor.

[0030] The high-pressure refrigerant circulating in the main loop heats the interior airflow and thus the vehicle's passenger compartment. The refrigerant circulating in the fourth branch joins the refrigerant from the first heat exchanger, and the resulting mixture, by releasing heat in the third heat exchanger, heats the vehicle's powertrain component.

[0031] According to the third example of implementation of the process: - 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.

[0032] According to this third example of implementation of the process: - The first regulator is 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 in the closed position.

[0033] According to a particular case of the third example of implementation of the process: - the flow rate of refrigerant circulating in the fourth branch of the bypass is less than a first predefined threshold, - the indoor airflow rate is less than a second predefined threshold.

[0034] The first predefined threshold is, for example, xx kg / h. The flow rate of refrigerant circulating in the fourth branch of the bypass can be zero. The second predefined threshold is, for example, xx kg / h. The flow rate of the indoor airflow can be zero.

[0035] The proposed control method may include the following steps: - determine a maximum permissible temperature of the refrigerant at the compressor outlet, - determine the temperature of the refrigerant at the compressor outlet, - control the expansion of the refrigerant in the first expansion valve so that the determined temperature is lower than the maximum temperature.

[0036] When the first heat exchange section of the internal heat exchanger is filled with refrigerant, controlling the refrigerant pressure in this first section allows control of the internal heat exchanger's efficiency, i.e., the amount of heat exchanged between the first and second heat exchange sections. This makes it possible to adjust the compressor inlet temperature, and therefore also the compressor outlet temperature. The compressor outlet temperature can thus be maintained at a value less than or equal to a maximum permissible temperature.

[0037] The control process may therefore include the following sub-steps: - reduce the cross-sectional area of ​​the refrigerant flowing through the first expansion valve if the determined temperature of the refrigerant at the compressor outlet is higher than a first target value, - increase the cross-section of the refrigerant passing through the first expansion valve if the determined temperature of the refrigerant at the compressor outlet is lower than the first target value.

[0038] The proposed control method may include the following steps: - determine the refrigerant pressure at the compressor outlet, - increase the cross-sectional area of ​​the refrigerant flow through the second expansion valve if the determined refrigerant pressure at the compressor outlet is greater than a second target value, - decrease a cross-section of the refrigerant passage through the second expansion valve if the determined pressure of the refrigerant at the compressor outlet is less than the second target value.

[0039] The control process may include the following sub-steps: - control the flow rate of refrigerant discharged by the compressor and control a section of refrigerant passage through the third expansion valve so as to control the pressure of the refrigerant in the second exchanger to a value greater than a predefined minimum threshold and so as to control the thermal power supplied by the first exchanger to a third target value.

[0040] The level of expansion applied by the third expansion valve, in combination with the flow rate supplied by the compressor, allows control of the low-pressure value of the The thermodynamic cycle, as well as the heating power supplied by the first heat exchanger, is determined by controlling the low pressure at a sufficiently high value. This limits the thermal power absorbed by the second heat exchanger, thus preventing it from freezing in cold environments.

[0041] The value of the predefined minimum pressure threshold may depend on the ambient temperature.

[0042] The control method may include the step: - control a compressor rotation speed in order to control the flow of refrigerant in the refrigerant circuit.

[0043] The control process comprises the following steps: - increase the compressor speed to increase the total flow rate in the refrigerant circuit, and - reduce the compressor rotation speed in order to decrease the total flow circulating in the refrigerant circuit.

[0044] The control process may include the following substeps: - determine the superheat of the refrigerant at the outlet of the third heat exchanger, - control a section of the refrigerant flow through the fourth expansion valve in order to adjust the superheat of the refrigerant at the outlet of the third exchanger to a fourth target value.

[0045] The control process may include the following substeps: - increase the cross-sectional area of ​​the refrigerant flowing through the fourth expansion valve if the determined superheat of the refrigerant at the outlet of the third heat exchanger is greater than the fourth target value. - decrease a cross-section of the refrigerant flow through the fourth expansion valve if the determined superheat of the refrigerant at the outlet of the third exchanger is less than the fourth target value.

[0046] The control process may include the following steps: - determine the thermal power supplied by the third heat exchanger to the traction chain element, - control a section of the refrigerant flow through the fifth expansion valve in order to adjust the thermal power supplied by the third exchanger to a fifth target value.

[0047] The thermal power supplied by the third exchanger to the traction chain element is, for example, determined from the value of the heat transfer fluid flow rate in the circuit, and from the value of the temperature difference of the heat transfer fluid between the inlet and outlet of the third exchanger.

[0048] The control process may include the following substeps: - increase the cross-sectional area of ​​the refrigerant flow through the fifth expansion valve if the thermal power supplied by the third heat exchanger is less than the fifth target value. - reduce the cross-section of the refrigerant flow through the fifth expansion valve if the thermal power supplied by the third exchanger is less than the fifth target value.

[0049] The control process may include 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 a passage cross-section of the refrigerant fluid 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.

[0050] The control process may include the following substeps: - increase the cross-sectional area of ​​the refrigerant flow through the fourth expansion valve when the determined temperature of the indoor air flow exiting the first heat exchanger is lower than the temperature setpoint, and - decrease a cross-section of the refrigerant flow through the fourth expansion valve if the determined temperature of the indoor air flow at the outlet of the first exchanger is greater than the temperature setpoint.

[0051] When the airflow through the first heat exchanger is low or even zero, the heat exchange performed by the first heat exchanger is negligible or zero. The refrigerant only heats the heat transfer fluid circulating in circuit 40 connected to the third heat exchanger. The circulation of refrigerant through the first heat exchanger ensures the return of oil to the compressor and prevents the accumulation of this oil in the first heat exchanger.

[0052] In this operating mode corresponding to the third example of implementation of the process: - the first regulator is in the closed position. - the sixth regulator is in the closed position. - the second regulator, the third regulator, the fourth regulator, and the fifth regulator are in the partially open position.

[0053] 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 internal airflow to the vehicle's passenger compartment, — a first regulator, — a second regulator, — a second heat exchanger configured to exchange heat with an outside airflow to the vehicle's passenger compartment, — a refrigerant accumulation device, the main loop comprising an internal exchanger configured to allow heat exchange between the refrigerant circulating between the first and second expansion valves and the refrigerant circulating downstream of the accumulation device and upstream of a compressor inlet, - 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 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.

[0054] According to one embodiment, the thermal conditioning system comprises: - A fifth branch connecting a ninth connection point located on the main loop between the first expansion valve and the sixth connection point to a tenth connection point located on the main loop between the second connection point and the fourth connection point, the fifth branch branch comprising successively a seventh expansion valve and a fourth heat exchanger configured to exchange heat with an internal airflow.

[0055] The fourth exchanger is arranged upstream of the first exchanger according to a direction of flow of the internal airflow.

[0056] 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.

[0057] The main loop includes a first shut-off valve disposed between the first connection point and the seventh connection point.

[0058] The main loop includes a second shut-off valve disposed between the second connection point and the fourth connection point.

[0059] The main loop includes a second shut-off valve disposed between the second connection point and the tenth connection point.

[0060] The first shut-off valve is an electrically operated valve. Similarly, the second shut-off valve is an electrically operated valve.

[0061] The refrigerant circuit includes a first one-way valve disposed on the main loop between the first exchanger and the third connection point.

[0062] The first one-way valve is configured to allow refrigerant fluid to circulate through the first one-way valve of the first exchanger to the third connection point. The first one-way valve is also configured to prohibit refrigerant flow through the first one-way valve from the third connection point to the first exchanger.

[0063] The refrigerant circuit includes a second one-way valve disposed on the third branch of the bypass.

[0064] The second one-way valve is configured to allow refrigerant fluid to circulate through the second one-way valve from the fifth connection point to the sixth connection point and configured to prohibit refrigerant fluid to circulate through the second one-way valve from the sixth connection point to the fifth connection point.

[0065] The refrigerant circuit includes a third one-way valve disposed on the main loop between the fourth exchanger and the tenth connection point.

[0066] The third one-way valve is configured to allow a flow of refrigerant fluid through the third one-way valve of the fourth exchanger to the tenth connection point.

[0067] The third one-way valve is also configured to prohibit refrigerant fluid circulation through the third one-way valve from the tenth connection point to the fourth exchanger.

[0068] The first one-way valve is, for example, a non-return valve.

[0069] Similarly, the second one-way valve and the third one-way valve can also be a check valve.

[0070] Alternatively, each one-way valve can be an electrically operated valve.

[0071] The disclosure also relates to a computer program stored in memory and configured to implement the process described above. Brief description of the drawings

[0072] Other features, details and advantages will become apparent upon reading the detailed description below, and upon analysis of the accompanying drawings, on which:

[0073] [Fig. 1] is a schematic view of a thermal conditioning system according to a first embodiment of the invention,

[0074] [Fig.2] is a schematic view of a thermal conditioning system according to a second embodiment of the invention,

[0075] [Fig.3] is a schematic view illustrating the operation of the conditioning system thermal operation of [Fig.2], according to a first example of implementation of the proposed process,

[0076] [Fig.4] is a schematic view illustrating the operation of the conditioning system thermal operation of [Fig.2], according to a second example of implementation of the proposed process,

[0077] [Fig.5] is a schematic view illustrating the operation of the conditioning system thermal operation of [Fig.2], according to a third example of implementation of the proposed process,

[0078] [Fig.6] is a block diagram of the proposed process. Description of the implementation methods

[0079] To facilitate reading the figures, the different elements are not necessarily shown 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 one can in- to change the names.

[0080] 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..

[0081] 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.

[0082] When it is specified that a subsystem includes a given element, this does not exclude the presence of other elements in that subsystem.

[0083] The thermal conditioning system 100, which will be described below, comprises an electronic control unit 62 that receives information from various sensors measuring, in particular, the characteristics of the refrigerant at various points in the circuit. The electronic control unit 62 also receives instructions from the vehicle occupants, for example, the desired temperature inside the passenger compartment. The electronic control unit 62 can also receive instructions from other electronic subsystems, such as a battery management system for electrical energy storage. The electronic control unit 62 implements control laws to operate the various actuators, in order to control the thermal conditioning system 100 and ensure compliance with the received instructions. Control unit 62 can execute software coding the proposed process.

[0084] 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 move the refrigerant from a low pressure to a high pressure. pressure on the inlet side 7a to a high pressure on the outlet side 7b. After expansion in one or more expansion devices 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.

[0085] The refrigerant circuit 10 forms a closed circuit in which the refrigerant can circulate. The refrigerant circuit 10 is leak-proof when it is in a nominal operating state, that is, without any fault or leak. Each connection point of circuit 10 allows the refrigerant to flow into one of the circuit sections that converge at that point. The refrigerant is distributed between these sections by opening or closing the shut-off valves, check valves, or expansion devices located on each section. In other words, each connection point redirects the refrigerant arriving at that point. Various shut-off valves and check valves thus allow the refrigerant to be selectively directed into the different branches of the refrigerant circuit, in order to provide different operating modes, as will be described later.

[0086] 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.

[0087] Each refrigerant expansion device, also called an expansion valve, can be an electronic expansion valve. In an electronic expansion valve, the passage area through which the refrigerant flows can be continuously adjusted between a closed position and a maximum open position. To achieve this, an electronic control module drives an electric motor that moves a movable shutter, thus controlling the passage area available to the refrigerant. In the closed position, the circulation of refrigerant is interrupted; that is, the flow of refrigerant through the electronic expansion valve is zero. In the maximum open position, the refrigerant flows through the expansion valve without undergoing any expansion.

[0088] 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.

[0089] The term "external airflow Fe" refers to an airflow that is not destined for the vehicle's passenger compartment. In other words, this airflow Fe remains outside the vehicle's passenger compartment. A second motor-fan unit, also not shown, can be activated to increase the flow rate of the outside airflow Fe if necessary. The airflow provided by 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.

[0090] 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".

[0091] 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.

[0092] Figure [Fig.1] shows a thermal conditioning system 100 for a motor vehicle, according to a first embodiment. 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 compressor 7, — a first heat exchanger 1 thermally coupled with an internal airflow Fi to a vehicle passenger compartment, — a first regulator 31, — a second regulator 32, — a second heat exchanger 2 configured to exchange heat with an outside airflow Fe to the vehicle's passenger compartment, — a refrigerant fluid accumulation device 8. The main loop A includes an internal exchanger 6 configured to allow heat exchange between the refrigerant circulating between the first expansion valve 31 and the second expansion valve 32 and the refrigerant circulating downstream of the storage device 8 and upstream of an inlet 7a of the compressor 7. The refrigerant circuit 10 comprises: - a first branch branch B connecting a first connection point 11 located on the main loop A downstream of an outlet 7b of the compressor 7 and upstream of the first exchanger 1 to a second connection point 12 located on the main loop A downstream of the second heat exchanger 2 and upstream of the accumulation device 8, the first branch branch B comprising a third expansion valve 33, - a second branch C connecting to a third connection point 13 arranged on the main loop A between the first exchanger 1 and the first expansion valve 31 to a fourth connection point 14 arranged 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 thermal conditioning system 100 includes an electronic control unit 62 configured to implement the process described below.

[0093] A computer program stored in memory can implement the proposed process. The memory can be integrated into the electronic control unit 62.

[0094] The refrigerant fluid circuit 10 is configured to circulate a refrigerant fluid. The compressor 7 changes the refrigerant fluid from a low pressure state, at the inlet 7a of the compressor 7, to a high pressure state, at the outlet 7b of the compressor 7. The accumulation device 8, also called an accumulator, forms a storage volume for liquid refrigerant. The accumulation device 8 compensates for variations in the amount 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 that the compressor 7 is supplied with refrigerant in gaseous form.

[0095] The thermal coupling between the first heat exchanger 1 and the internal airflow Fi can be ensured in different ways.

[0096] According to the example in [Fig.1], the first heat exchanger 1 is configured to exchange heat with a heat transfer fluid circulating in a heat transfer fluid circuit 30, the heat transfer fluid circuit 30 comprising a heat exchanger IA configured to exchange heat with the interior airflow Fi to the vehicle's passenger compartment.

[0097] A pump, not shown, circulates the heat transfer fluid in circuit 30. Circuit 30 forms a closed circuit. Circuit 30 is leak-proof during nominal operation of the thermal conditioning system 100, that is, when the system is fully assembled and functioning without fault. The heat transfer fluid circulating in circuit 30 is, for example, a mixture of water and glycol.

[0098] The thermal coupling between the first heat exchanger 1 and the interior airflow Fi is in this case said to be indirect, since it is achieved through the heat transfer fluid of the circuit 30 which transfers the heat supplied by the refrigerant fluid to the airflow Fi supplying the passenger compartment of the vehicle. The IA heat exchanger of the heat transfer fluid circuit, also called a heater core, is located in the heating, ventilation and / or air conditioning system of the vehicle.

[0099] According to the example in [Fig.2], the first heat exchanger 1 is configured to exchange heat with the interior airflow Fi to the vehicle's passenger compartment.

[0100] The thermal coupling between the first heat exchanger 1 and the internal airflow Fi is in this case said to be direct. Indeed, the internal airflow Fi is in contact with the walls of the heat exchanger 1 in which the refrigerant circulates. In this embodiment, the first heat exchanger 1 is located in the vehicle's heating, ventilation and / or air conditioning system.

[0101] 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. 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. When the first heat exchange section 6a is not traversed by a flow of refrigerant fluid, there is no heat exchange in the internal exchanger 6.

[0102] The second embodiment of the thermal conditioning system 100, illustrated in [Fig.2], also differs from the first embodiment by the presence of an additional refrigerant circulation branch.

[0103] The thermal conditioning system 100 thus comprises a fifth branch F connecting a ninth connection point 19 located on the main loop A between the first expansion valve 31 and the sixth connection point 16 to a tenth connection point 20 located on the main loop A between the second connection point 12 and 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.

[0104] The fourth heat exchanger 4 is disposed in the vehicle's heating, ventilation and / or air conditioning system. The fourth exchanger 4 is positioned upstream of the first exchanger 1 according to a direction of flow of the internal air flow Fi. The fourth interchange 4 allows the interior airflow and thus the vehicle's passenger compartment to be cooled.

[0105] In this second embodiment in which 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 circulating downstream of the accumulation device 8 and upstream of an inlet 7a of the compressor 7.

[0106] The second branch C includes a sixth regulator 36 disposed between the fourth connection point 14 and the fifth connection point 15.

[0107] 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.

[0108] The main loop A includes a first shut-off valve 41 disposed between the first connection point 11 and the seventh connection point 17.

[0109] In the first embodiment corresponding to [Fig. 1], the main loop A includes a second shut-off valve 42 disposed between the second connection point 12 and the fourth connection point 14. In the second embodiment corresponding to [Fig.2], the main loop A includes a second shut-off valve 42 disposed between the second connection point 12 and the tenth connection point 20.

[0110] 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 is, for example, controlled by the electronic control unit 62.

[0111] The refrigerant fluid circuit 10 includes a first one-way valve 43 disposed on the main loop A between the first exchanger 1 and the third connection point 13. The first one-way valve 43 is configured to allow refrigerant 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 The function 43 is also configured to prohibit refrigerant flow through the first one-way valve 43 from the third connection point 13 to the first exchanger 1.

[0112] The refrigerant fluid circuit 10 includes a second one-way valve 44 disposed on the third branch branch D. The second one-way valve 44 is configured to allow refrigerant flow through the second one-way valve 44 from the fifth connection point 15 to the sixth connection point 16 and configured to prohibit refrigerant flow through the second one-way valve 44 from the sixth connection point 16 to the fifth connection point 15.

[0113] 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. 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 tenth connection point 20. The third one-way valve 45 is also configured to prohibit refrigerant flow through the third one-way valve 45 from the tenth connection point 20 to the fourth exchanger 4.

[0114] 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. A check valve is a passive device that reacts to the pressure difference between its inlet and outlet. No electrical control is required for its operation. Alternatively, each one-way valve 43, 44, 45 can be an electrically operated valve.

[0115] 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. According to another variant or in a complementary manner, element 25 of the vehicle's electric drive chain includes an electronic control unit for the vehicle's electric traction motor.

[0116] According to the illustrated example, the third heat exchanger 3 is thermally coupled with the element 25 of the electric traction chain via a heat transfer fluid circulating in a heat transfer fluid circuit 40. A circulation pump, not shown, allows the heat transfer fluid to circulate in circuit 40. According to the schematic example, circuit 30 and circuit 40 are independent, that is to say, they are not connected.

[0117] The heat transfer fluid circulating in the heat transfer fluid circuit 40 can exchange heat on the one hand with the refrigerant circulating in the third heat exchanger 3 and on the other hand with the element 25 of the vehicle's electric powertrain. The heat transfer fluid thus enables heat transfer between the refrigerant and the element 25 of the electric powertrain. For example, the heat transfer fluid circulates between the battery elements, or inside the wall of the electric motor casing. The heat transfer fluid circulating in circuit 40 is, for example, a mixture of water and glycol.

[0118] Each regulator 31, ..., 37 is for example an electronic regulator.

[0119] The thermal conditioning system 100 can operate in several modes. The proposed method, when implemented, corresponds to a particular operating mode of the thermal conditioning system 100.

[0120] A method for controlling a thermal conditioning system for a motor vehicle is thus proposed. The thermal conditioning system 100 comprises a refrigerant circuit 10 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 internal airflow Fi to a vehicle passenger compartment, — a first regulator 31, — a second regulator 32, — a second heat exchanger 2 configured to exchange heat with an outside airflow Fe to the vehicle's passenger compartment, — a refrigerant fluid accumulation device 8, the main loop A 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 circulating downstream of the accumulation device 8 and upstream of an inlet 7a of the compressor 7, - a first branch B connecting a first connection point 11 located on the main loop A downstream of an outlet 7b of the compressor 7 and upstream of the first heat exchanger 1 to a second connection point 12 located on the main loop A downstream of the second heat exchanger 2 and upstream of the accumulation device 8, the first branch B comprising a third expansion valve 33, - a second branch C connecting a third connection point 13 located on the main loop A between the first 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 proposed process includes the following steps: (i) provide a first flow Q1 of high-pressure refrigerant at the outlet of compressor 7, (ii) divide the first flow Q1 of high-pressure 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) circulate at least a portion of the second flow Q2 of high-pressure refrigerant through the first heat exchanger 1, (iv) reduce at least a portion of the high-pressure refrigerant from the first heat exchanger 1 to a low pressure, (v) circulate the low-pressure refrigerant through the second exchanger 2, (vi) reduce the third flow Q3 to low pressure so that the third flow Q3 joins the refrigerant from the second exchanger 2 to form the first flow Q1, the first flow Q1 of low-pressure refrigerant joining the compressor 7.

[0121] In the proposed process, the thermal energy extracted from the outside airflow Fe at the level of the second exchanger 2 contributes to heating the vehicle's passenger compartment at the level from the first heat exchanger 1. The flow of refrigerant circulating in the first branch of the bypass B provides the thermal energy to close the thermodynamic cycle while limiting the amount of heat extracted from the outside air flow Fe. The risks of icing of the second heat exchanger 2 are thus reduced, without limiting the thermal power supplied to the passenger compartment.

[0122] The steps described account for the proposed process, taking the compressor 7 as the starting point for the refrigerant circulation. The various steps do not necessarily occur in the order described. In particular, if a refrigerant flow is split into two flows at a connection point, these two flows continue to circulate simultaneously, and no order can be defined.

[0123] According to the proposed process, the first exchanger 1 operates as a refrigerant fluid cooler. The first exchanger 1 thus allows the indoor air flow Fi to be heated, either directly or indirectly.

[0124] According to the proposed process, the second exchanger 2 operates as a refrigerant fluid evaporator. The second exchanger 2 thus allows the absorption of thermal power from the outside air flow Fe.

[0125] According to the proposed process, the third exchanger 3 can operate as a refrigerant fluid cooler. The third heat exchanger 3 allows the element 25 of the vehicle's electric powertrain to be heated. The element 25 of the vehicle's electric powertrain can thus be maintained, or placed, within a preferred temperature range corresponding to the optimal operation of this element. According to operating modes not shown, the third exchanger 3 can operate as a refrigerant fluid evaporator.

[0126] Figures 3 to 5 illustrate the circulation of the refrigerant fluid in the circuit 10 when the proposed process is implemented on a thermal conditioning system 100 according to the second embodiment, the architecture of which is illustrated in [Fig.2]. The portions of circuit 10 in which refrigerant flows are shown with a thick solid line, while the portions in which refrigerant does not flow are shown with thin dashed lines. The different arrows indicate the direction of refrigerant flow in the different portions of the refrigerant circuit 10.

[0127] Fig. 3 schematically illustrates the operation of the thermal conditioning system according to a first example of implementation of the process. According to this first example, the refrigerant from the first heat exchanger 1 flows through the first expansion valve 31 where it passes through an intermediate pressure, into the internal heat exchanger 6, and then into the second expansion valve 32 where it passes through a low pressure.

[0128] According to this first embodiment, the flow rate of refrigerant circulating in the second heat exchanger 2 is equal to the flow rate of refrigerant circulating in the first heat exchanger 1. We understand that the two flow rates are equal during steady-state operation, that is, when a thermal equilibrium is reached.

[0129] The value of the so-called "high pressure" at the outlet of the compressor 7 is, for example, between 40 bars and 130 bars. The value of the so-called "intermediate" pressure, after expansion for example by the first regulator 31, is lower than the value of the high pressure. The intermediate pressure is, for example, between 20 bar and 70 bar. The value of the so-called "low pressure", after expansion for example in the second regulator 32, is less than the value of the intermediate pressure. Low pressure, for example, is between 10 bars and 40 bars.

[0130] According to this first example of implementation of the process: - The first regulator 31 is in the partially open position. - 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 closed position. - The fifth regulator 35 is in the closed position. - The sixth regulator 36 is in the closed position.

[0131] According to this first example of implementation, the refrigerant circulating in the main loop A downstream of the first connection point 11 passes successively through the first exchanger 1, the first expansion valve 31, the first heat exchange section 6a of the internal exchanger 6, the second expansion valve 32, the second exchanger 2, and reaches the second connection point 12. The refrigerant circulating in the first branch of the bypass B flows through the third expansion valve 33 and joins at the second connection point 12 the refrigerant coming from the second exchanger 2. These two refrigerant flows are thus combined into a single flow. This single flow circulates in the main loop A to the fourth connection point 14, then in the accumulation device 8, in the second heat exchange section 6b of the internal exchanger 6, and reaches the inlet 7a of the compressor 7. The first shut-off valve 41 and the second shut-off valve 42 are both in the open position.

[0132] Fig. 4 schematically illustrates the operation of the thermal conditioning system according to a second example of implementation of the process. According to this second example of implementation of the process, the second flow Q2 of high-pressure refrigerant circulates in the first exchanger 1 and is divided into a first part Q2A circulating in the main loop A and a second part Q2C circulating in the second branch of bypass C. The refrigerant Q2C circulating in the second branch of the bypass C flows into the fourth expansion valve 34 where it passes through a low pressure, and the low-pressure refrigerant from the third exchanger 3 joins the low-pressure refrigerant from the second exchanger 2 and the first branch of bypass B.

[0133] In this second embodiment, the low-pressure refrigerant circulating in the third heat exchanger 3 recovers the heat dissipated by the thermal losses of the element 25 of the vehicle's electric powertrain. Energy efficiency is thus improved.

[0134] The refrigerant circulating in the main loop A from the third connection point 13 to the sixth connection point 16 flows through the first expansion valve 31 and passes to intermediate pressure.

[0135] According to this second example of implementation of the process: - The first regulator 31 is in the partially open position. - 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 closed position. - The sixth regulator 36 is in the fully open position.

[0136] In steady state, the flow rate of refrigerant Q2A circulating in the second exchanger 2 is less than the flow rate of refrigerant Q2 circulating in the first exchanger 1. Indeed, part of the refrigerant fluid from the first exchanger 1 then circulates in the third exchanger 3 and reaches the compressor 7 without passing through the second exchanger 2.

[0137] According to this second example of implementation, the circulation of the refrigerant fluid in the main loop A between the first connection point 11 and the third connection point 13 is identical to the first example. Similarly, the traffic in the first branch of derivation B is identical to the first example. At the third connection point, the Q2 flow rate of refrigerant from the first heat exchanger 1 is divided into a first part Q2A which circulates in the main loop A towards the first expansion valve 31 and a second part Q2C which circulates in the second branch C towards the fourth expansion valve 34. The first part Q2A circulates successively in the first expansion valve 31, the first heat exchange section 6a of the internal exchanger 6, the second expansion valve 32, the second exchanger 2, and joins at the second connection point 12 the refrigerant from the first branch B. As in the first example, these two refrigerant flows combine into a single flow which circulates in the main loop A up to the fourth connection point 14. The second part Q2C flows through the fourth expansion valve 34 and passes to low pressure, then through the third exchanger 3, then through the sixth expansion valve 36, and joins at the fourth connection point 14 the refrigerant circulating in the main loop A. The refrigerant flow resulting from the union of the two flows at point 14 circulates successively in the accumulation device 8, in the second heat exchange section 6b of the internal exchanger 6, and joins the inlet 7a of the compressor 7.

[0138] The first stop valve 41 and the second stop valve 42 are both in the open position. The second one-way valve 44 prevents the intermediate pressure refrigerant at the sixth connection point 16 from flowing in the third branch D towards the fifth connection point 15.

[0139] Fig. 5 schematically illustrates the operation of the thermal conditioning system according to a third example of implementation of the process. According to this third example of process implementation, the second flow Q2 of high-pressure refrigerant circulating in the main loop A is divided into a first part Q2-1 circulating in the first heat exchanger 1 and then in the second branch C, and a second part Q2-2 complementary to the first part Q2-1 circulating in the fourth branch E. The first part Q2-1 and the second part Q2-2 rejoin upstream of the third heat exchanger 3 and form the second flow Q2. The second flow Q2 circulates successively in the third heat exchanger 3, in the second branch C, in the third branch D, in the second expansion valve 32, and in the second heat exchanger 2. The second flow Q2 joins the third flow Q3 and forms the first flow Ql, the first flow Ql joining the compressor 7.

[0140] The high-pressure refrigerant circulating in the main loop A heats the interior airflow Fi and thus the vehicle's passenger compartment. The refrigerant circulating in the fourth branch of the bypass E joins the refrigerant fluid from the first exchanger 1, and the resulting mixture allows, by releasing heat in the third exchanger 3, to heat the element 25 of the vehicle's traction chain.

[0141] According to this third example of implementation of the process: - the refrigerant from the first heat 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.

[0142] According to this third example of implementation of the process: - The first regulator 31 is in the closed position. - 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 in the closed position.

[0143] In steady state, the flow rate of refrigerant circulating in the second exchanger 2 is greater than the flow rate of refrigerant circulating in the first exchanger 1. The flow rate of refrigerant circulating in the second exchanger 2 is equal to the flow rate of refrigerant circulating in the third exchanger 3, this flow rate being designated by Q2. Indeed, the refrigerant from the first exchanger 1 is joined by the refrigerant circulating in the fourth branch of the bypass E, and the whole then joins the second exchanger 2 by passing successively through the third exchanger 3, through the third branch of the bypass D and through the second expansion valve 32.

[0144] According to this third example of implementation, the circulation of the refrigerant in the main loop A between the first connection point 11 and the seventh connection point 17 is identical to the first and second examples. Similarly, the traffic in the first branch of derivation B is identical to the first and second examples. At the seventh connection point 17, the refrigerant flow Q2 is divided into a first part Q2-1 which circulates in the main loop A towards the first exchanger 1 and a second part Q2-2 which circulates in the fourth branch E towards the fifth expansion valve 35. The first part Q2-1 flows through the first exchanger 1, is redirected at the third connection point 13 to the second branch of bypass C and passes through the fourth regulator 34. At the eighth connection point 18, the refrigerant from the fourth expansion valve 34 and the refrigerant from the fifth expansion valve 35 join. The resulting flow Q2 passes through the third heat exchanger 3, then is redirected at the fifth heat exchanger 5 to the third branch line D, and rejoins the main loop A at the sixth connection point 16. The sixth connection point 16 is downstream of the first heat exchange section 6a, which is therefore not traversed by refrigerant. The refrigerant flow Q2 from the third branch D flows successively through the second expansion valve 32 and then through the second heat exchanger 2, and, as in the other two examples of process implementation, joins the refrigerant flow Q3 from the third expansion valve 33. As before, the resulting flow Q1 circulates in the main loop A to the fourth connection point 14, then into the accumulator 8, into the second heat exchange section 6b of the internal exchanger 6, and returns to the inlet 7a of the compressor 7.

[0145] According to a particular case of the third example of implementation of the process: - the flow rate of refrigerant circulating in the fourth branch of the bypass E is less than a first predefined threshold, - the indoor air flow rate Fi is less than a second predefined threshold.

[0146] The first predefined threshold is, for example, xx kg / h. The flow rate of refrigerant circulating in the fourth branch of bypass E can be zero. The second predefined threshold is, for example, xx kg / h. The indoor airflow rate Fi can be zero. To achieve this, the first fan motor unit can be kept off. Alternatively, or in addition, a movable flap, not shown, can be positioned to block the airflow.

[0147] When the indoor airflow rate Fi is below the first predefined threshold, the heat exchange in the first heat exchanger 1 is negligible. When the flow rate of the indoor airflow Fi is zero, there is no heat exchange at the first exchanger 1. When the flow rate of refrigerant circulating in the fourth branch of bypass E is also zero, the first exchanger 1 and the third exchanger 3 are connected in series without supply of refrigerant between the outlet 1b of the first exchanger 1 and the inlet 3a of the third exchanger 3. All the energy of the refrigerant reaching the first heat exchanger 1 allows for The element 25 of the traction chain is heated at the third heat exchanger 3. When the flow rate of refrigerant circulating in the fourth branch E is below the second predefined threshold, the thermal energy input from the fourth branch E is negligible. The heat exchange in the third heat exchanger 3 is carried out by the refrigerant from the first heat exchanger 1.

[0148] The principle of the control enabling the operation of the various actuators of the thermal conditioning system 100 will now be described.

[0149] A control of the expansion carried out by the first expansion valve 31 makes it possible to limit the discharge temperature of the compressor 7.

[0150] The proposed control method thus comprises the following steps: - determine a maximum permissible temperature Tmax of the refrigerant at the compressor outlet 7, - determine a temperature T7 of the refrigerant at the outlet of the compressor 7, - control an expansion of the refrigerant in the first expansion valve 31 so that the determined temperature T7 is less than the maximum temperature Tmax.

[0151] When the first heat exchange section 6a of the internal heat exchanger 6 is traversed by refrigerant, controlling the refrigerant pressure in the first heat exchange section 6a allows control of the efficiency of the internal heat exchanger 6, i.e., the amount of heat exchanged between the first heat exchange section 6a and the second heat exchange section 6b. It is thus possible to adjust the temperature at the inlet 7a of the compressor 7, and therefore also the discharge temperature at the outlet 7b of the compressor 7. The discharge temperature T7 of the compressor 7 can thus be maintained at a value less than or equal to a maximum permissible temperature.

[0152] The control process may therefore include the following sub-steps: - decrease the cross-sectional area of ​​the refrigerant flow through the first expansion valve 31 if the determined temperature T7 of the refrigerant at the outlet of the compressor 7 is greater than a first target value, - increase a cross-section of the refrigerant passing through the first expansion valve 31 if the determined temperature T7 of the refrigerant at the outlet of the compressor 7 is less than the first target value.

[0153] A control of the expansion carried out by the second expansion valve 32 makes it possible to control the discharge pressure of the compressor 7, and thus the value of the high pressure of the thermodynamic cycle.

[0154] The proposed control method thus comprises the following steps: - determine a pressure P7 of the refrigerant at the outlet of compressor 7, - increase the cross-sectional area of ​​the refrigerant passage through the second expansion valve 32 if the determined pressure P7 of the refrigerant at the outlet of compressor 7 is greater than a second target value, - decrease a cross-section of the refrigerant passage through the second expansion valve 32 if the determined pressure P7 of the refrigerant at the outlet of the compressor 7 is less than the second target value.

[0155] Joint control of the flow circulating in the refrigerant circuit 10 and the expansion carried out by the third expansion valve 33 makes it possible to control the heating power supplied by the first exchanger 1 while limiting the thermal power absorbed from the outside air flow Fe at the level of the second exchanger 2.

[0156] The first heat exchanger 1 provides a thermal power PL. The control process can thus comprise the following sub-steps: - control the flow rate Q1 of refrigerant discharged by the compressor 7 and control a section of the refrigerant passage through the third expansion valve 33 so as to control the pressure of the refrigerant in the second exchanger 2 to a value greater than a predefined minimum threshold and so as to control the thermal power PI supplied by the first exchanger 1 to a third target value.

[0157] The expansion level applied by the third expansion valve 33 allows, in combination with the flow supplied by the compressor 7, to control the value of the low pressure of the thermodynamic cycle as well as the heating power supplied by the first exchanger 1, i.e. that supplied by the first exchanger 1. By controlling the low pressure at a sufficiently high value, the thermal power absorbed by the second exchanger 2 is limited, which prevents the second exchanger 2 from freezing in cold conditions.

[0158] The value of the predefined minimum pressure threshold may depend on the ambient temperature. The process can thus include the following sub-steps: - determine the temperature of the outside airflow Fe, - determine the value of the predefined minimum pressure threshold as a function of the determined temperature of the outside airflow.

[0159] The control process includes the step: - control a compressor rotation regime 7 in order to control the flow of refrigerant fluid in the refrigerant fluid circuit 10.

[0160] The total flow circulating in the refrigerant fluid circuit 10 is the flow discharged by the compressor 7.

[0161] The inspection process comprises the following steps: - increase the rotational speed of compressor 7 in order to increase the total flow rate circulating in the refrigerant circuit 10, and - reduce the rotation speed of compressor 7 in order to decrease the total flow rate circulating in the refrigerant fluid circuit 10.

[0162] A control of the expansion carried out by the fourth expansion valve 34 makes it possible to control the value of the superheat of the refrigerant fluid at the outlet of the third exchanger 3.

[0163] The control process may include the following substeps: - determine the superheat Sh3 of the refrigerant at the outlet of the third heat exchanger 3, - control a section of the refrigerant flow through the fourth expansion valve 34 so as to adjust the superheat Sh3 of the refrigerant at the outlet of the third exchanger 3 to a fourth target value.

[0164] The control process may include the following substeps: - increase the cross-sectional area of ​​the refrigerant passing through the fourth expansion valve 34 if the determined superheat Sh3 of the refrigerant at the outlet of the third heat exchanger 3 is greater than the fourth target value, - reduce a cross-section of the refrigerant passage through the fourth expansion valve 34 if the determined superheat Sh3 of the refrigerant at the outlet of the third exchanger 3 is less than the fourth target value.

[0165] The superheat of the refrigerant is defined by the difference between the temperature of the refrigerant and the saturation temperature of the refrigerant, this saturation temperature being that corresponding to the pressure of the refrigerant.

[0166] A control of the expansion carried out by the fifth expansion valve 35 allows the heating power supplied by the third exchanger 3 to be controlled.

[0167] The inspection process may include the following steps: - determine a thermal power P3 supplied by the third heat exchanger 3 to element 25 of the traction chain, - control a section of the refrigerant flow through the fifth expansion valve 35 so as to adjust the thermal power P3 supplied by the third exchanger 3 to a fifth target value.

[0168] The thermal power supplied by the third heat exchanger 3 to the element 25 of the traction chain is, for example, determined from the value of the heat transfer fluid flow rate in the circuit 40, and from the value of the temperature difference of the heat transfer fluid between the inlet and outlet of the third heat exchanger 3. The heat capacity of the heat transfer fluid is also taken into account in the calculation of the thermal power supplied by the third exchanger 3.

[0169] The control process may include the following substeps: - increase the cross-sectional area of ​​the refrigerant passing through the fifth expansion valve 35 if the thermal power supplied by the third heat exchanger 3 is less than the fifth target value, - reduce the cross-sectional area of ​​the refrigerant passage through the fifth expansion valve 35 if the thermal power supplied by the third exchanger 3 is less than the fifth target value.

[0170] When the thermal coupling between the first exchanger 1 and the internal airflow Fi is a direct coupling, a control of the expansion carried out by the fourth expansion valve 34 makes it possible to control the temperature of the internal airflow Fi after exchange with the first exchanger 1.

[0171] The inspection process may include the following steps: - receive a temperature setpoint Tel of the indoor airflow Fi at the outlet of the first exchanger 1, - determine a temperature Tl of the indoor airflow Fi at the outlet of the first exchanger 1, - control a section of the refrigerant flow 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 Tel.

[0172] The control process may include the following substeps: - increase the cross-sectional area of ​​the refrigerant flow through the fourth expansion valve 34 if the determined temperature Tl of the indoor air flow Fi at the outlet of the first heat exchanger 1 is lower than the temperature setpoint Tel, and - decrease a cross-section of the refrigerant fluid passing through the fourth expansion valve 34 if the determined temperature Tl of the indoor air flow Fi at the outlet of the first exchanger 1 is greater than the temperature setpoint Tel.

[0173] When the air flow rate Fi through the first heat exchanger 1 is low or even zero, the heat exchange performed by the first heat exchanger 1 is negligible or zero. However, refrigerant circulation through the first heat exchanger 1 is maintained to ensure the return of the oil contained in the refrigerant to the compressor 7, and thus prevent an accumulation of this oil in the first heat exchanger 1.

[0174] When the thermal coupling between the first exchanger 1 and the indoor air flow Fi is an indirect coupling, the principle is the same and the temperature Tl of the indoor air flow Fi at the outlet of the first exchanger 1 is replaced by a temperature Tl A of the indoor air flow Fi at the outlet of the exchanger IA of the heat transfer fluid circuit 40. The same applies to the temperature setpoint Tel of the indoor air flow Fi at the outlet of the first exchanger 1 which is replaced by a temperature setpoint Tel A of the indoor air flow Fi at the outlet of the exchanger IA of the heat transfer fluid circuit 40.

[0175] According to this particular operation of the third example of implementation of the process: - the first regulator 31 and the sixth regulator 36 are in the closed position, - the second regulator 32, the third regulator 33, the fourth regulator 34, and the fifth regulator 35 are in the partially open position.

[0176] The fifth expansion valve 35 can optionally be in the closed position. In this case, the first heat exchanger 1 and the third heat exchanger 3 are connected in series, and the refrigerant can successively heat the internal airflow Fi and then the heat transfer fluid of the heat transfer fluid circuit 40.

[0177] Thus, the refrigerant fluid from the first exchanger 1 is redirected at the third connection point 13 to the fourth expansion valve 34 and the third exchanger 3. The refrigerant circulating in the fourth branch of the bypass E joins at the level of the eighth connection point 18 the refrigerant coming from the fourth expansion valve 34. The resulting flow is directed at the fifth connection point 15 to the third branch of the bypass D and joins the main loop A at the sixth connection point 16.

[0178] According to the illustrated examples of implementation of the process, the fourth heat exchanger 4 does not participate in heat exchange. The seventh expansion valve 37 is in the closed position, and the fifth bypass branch F does not carry a flow of refrigerant.

Claims

Demands

1. A 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 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 outside airflow (Fe) to the vehicle's passenger compartment, — a refrigerant fluid accumulation device (8), the main loop (A) 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 circulating downstream of the accumulation device (8) and upstream of an inlet (7a) of the compressor (7), - A first branch (B) connecting a first connection point (11) located on the main loop (A) downstream of an outlet (7b) of the compressor (7) and upstream of the first 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 (B) comprising a third expansion valve (33), - A second branch 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 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 to a fifth connection point (15) located on the second branch (C) at downstream of the third heat 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), - 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 expansion valve (34) and upstream of the third heat exchanger (3), the fourth branch (E) comprising a fifth expansion valve (35), the process comprising the steps: (i) supplying a first flow rate (Ql) of high-pressure refrigerant at the outlet of the compressor (7),(ii) divide the first flow (Ql) of high-pressure 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) circulate at least a portion of the second flow (Q2) of high-pressure refrigerant through the first heat exchanger (1), (iv) reduce at least a portion of the high-pressure refrigerant from the first heat exchanger (1) to a low pressure, (v) circulate the low-pressure refrigerant through the second heat exchanger (2), (vi) reduce the third flow (Q3) to a low pressure so that the third flow (Q3) rejoins the refrigerant from the second heat exchanger (2) to form the first flow (Ql), the first flow (Ql) of low-pressure refrigerant then returning to the compressor (7).

2. A method according to claim 1, wherein the refrigerant from the first exchanger (1) flows through the first expansion valve (31) where it passes at intermediate pressure, through the internal exchanger (6), then through the second expansion valve (32) where it passes at low pressure, and wherein the flow rate of refrigerant flowing through the second exchanger (2) is equal to the flow rate of refrigerant flowing through the first exchanger (1).

3. A method according to claim 1, wherein the second flow rate (Q2) of

4.

5.

6. high pressure refrigerant fluid circulates in the first exchanger (1) and divides into a first part (Q2A) circulating in the main loop (A) and a second part (Q2C) circulating in the second branch of bypass (C), in which the refrigerant (Q2C) circulating in the second branch of bypass (C) flows into the fourth expansion valve (34) where it passes to low pressure, and in which the low pressure refrigerant fluid from the third exchanger (3) joins the low pressure refrigerant fluid from the second exchanger (2) and the first branch of bypass (B). A method according to claim 1, wherein the second flow (Q2) of high-pressure refrigerant circulating in the main loop (A) is divided into a first portion (Q2-1) circulating in the first heat exchanger (1) and then in the second bypass branch (C), and a second portion (Q2-2) complementary to the first portion (Q2-1) circulating in the fourth bypass branch (E), the first portion (Q2-1) and the second portion (Q2-2) joining upstream of the third heat exchanger (3) and forming the second flow (Q2), the second flow (Q2) circulating successively in the third heat exchanger (3), in the second bypass branch (C), in the third bypass branch (D), in the second expansion valve (32), in the second heat exchanger (2), the second flow (Q2) joining the third flow (Q3) and forming the first flow (Q1), the first flow (Q1) returning to the compressor (7). A method according to claim 4, wherein: - the refrigerant from the first heat 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 bypass (D) is expanded by the second expansion valve (32) to a low pressure lower than the intermediate pressure. The method according to claim 4, wherein: - the flow rate of refrigerant circulating in the fourth branch of the bypass (E) is less than a first predefined threshold, - the indoor airflow rate (Fi) is less than a second predefined threshold.

7. A control method according to any one of the preceding claims, comprising the steps: - determining a maximum allowable temperature (Tmax) of the refrigerant at the outlet of the compressor (7), - determining a temperature (T7) of the refrigerant at the outlet of the compressor (7), - controlling an expansion of the refrigerant in the first expansion valve (31) so that the determined temperature (T7) is less than the maximum temperature (Tmax).

8. A control method according to any one of the preceding claims, comprising the steps: - determining a pressure (P7) of the refrigerant at the outlet of the compressor (7), - increasing a cross-section of the refrigerant passage through the second expansion valve (32) if the determined pressure (P7) of the refrigerant at the outlet of the compressor (7) is greater than a second target value, - decreasing a cross-section of the refrigerant passage through the second expansion valve (32) if the determined pressure (P7) of the refrigerant at the outlet of the compressor (7) is less than the second target value.

9. A control method according to any one of claims 1 to 3, wherein the first exchanger (1) provides a thermal power (PI), the method comprising the substeps: - controlling a flow rate (Ql) of refrigerant discharged by the compressor (7) and controlling a cross-section of the refrigerant through the third expansion valve (33) so as to control the pressure of the refrigerant in the second exchanger (2) at a predefined minimum threshold and so as to control at a third target value the thermal power (PI) supplied by the first exchanger (1).

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

11. A control method according to claim 3, comprising the substeps - determine a superheat (Sh3) of the refrigerant at the outlet of the third exchanger (3), - control a cross-section of the refrigerant through the fourth expansion valve (34) so ​​as to adjust the superheat (Sh3) of the refrigerant at the outlet of the third exchanger (3) to a fourth target value.

12. A control method according to claim 4, comprising the steps: - determining a thermal power (P3) supplied by the third exchanger (3) to the element (25) of the traction chain, - controlling a passage section of the refrigerant fluid through the fifth expansion valve (35) so as to adjust the thermal power (P3) supplied by the third exchanger (3) to a fifth target value.

13. A control method according to claim 4 or 12, comprising the steps: - receiving a temperature setpoint (Tel) 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 a cross-section of the refrigerant flow 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 (Tel).

14. A thermal conditioning system (100) for a motor vehicle, comprising a refrigerant circuit (10) having: - A main loop (A) comprising successively, according to the direction of refrigerant flow: — a compressor (7), — a first heat exchanger (1) thermally coupled with an interior airflow (Fi) to a vehicle passenger compartment, — a first expansion valve (31), — a second expansion valve (32), — a second heat exchanger (2) configured to exchange heat with an exterior airflow (Fe) to the vehicle passenger compartment, — a refrigerant storage device (8), the main loop (A) comprising an internal heat exchanger (6) configured to allow heat exchange between the refrigerant flowing between the first expansion valve (31) and the second expansion valve (32) and the refrigerant flowing downstream of the storage device (8) and in upstream of an inlet (7a) of the compressor (7), - A first branch (B) connecting a first connection point (11) located on the main loop (A) downstream of an outlet (7b) of the compressor (7) and upstream of the first 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 (B) comprising a third expansion valve (33), - A second branch 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 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), - A fifth branch (F) connecting a ninth connection point (19) located on the main loop (A) between the first expansion valve (31) and the sixth connection point (16) to a tenth connection point (20) located 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 airflow interior (Fi), - an electronic control unit (62) configured to implement the process according to one of the preceding claims.

15. Computer program stored in memory and configured to implement the method according to any one of claims 1 to 13.

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