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 and second expansion valves (31, 32), - a second heat exchanger (2), - A bypass branch (E), the method comprising the steps: (i) supplying a flow rate (Q) of high-pressure refrigerant, (ii) circulating a first portion (Q1) of the high-pressure refrigerant in the first heat exchanger (1) and a second portion (Q2) in the bypass branch (E), (iii) expanding the refrigerant circulating in the bypass branch (E) to an intermediate pressure, and expanding the refrigerant from the first heat exchanger (1) to the intermediate pressure, (iv) circulating the refrigerant at intermediate pressure in the third heat exchanger (3),and relax it to a low pressure. Figure from the summary: 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 rate provided by each of the expansion devices upstream of these exchangers. Possible operating modes include heating and cooling the vehicle passenger compartment, as well as heating and cooling the battery cells storing electrical energy.

[0003] Heating methods are frequently achieved by a so-called heat pump cycle in which the heat from the high-pressure refrigerant is transferred to one or more components to be heated, and in which the heat required for the vaporization of the low-pressure refrigerant is taken from an outside air stream.

[0004] When the ambient temperature drops, and particularly when it falls below freezing, the heat output that can be extracted from the outside airflow decreases, which also limits the available heating power. Furthermore, the heat exchanger in which the refrigerant evaporates is susceptible to frost, further limiting the heating capacity. It is therefore difficult to obtain sufficient heating power to warm the passenger compartment or the battery components.

[0005] It is therefore desirable to be able to heat the vehicle's passenger compartment using another method, and to be able to adjust the heating parameters on demand. Summary

[0006] 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, a third heat exchanger thermally coupled with an element of an electric traction chain of a motor vehicle, and a fifth expansion valve, - a third branch connecting a fifth connection point located on the second branch downstream of the third heat exchanger and upstream of the fourth connection point to a sixth connection point located on the main loop between the first and second pressure 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 heat exchanger to an eighth connection point located on the second branch downstream of the fourth pressure regulator and upstream of the third heat exchanger, the fourth branch comprising a sixth pressure regulator, the process comprising the following steps: (i) supply a high-pressure refrigerant flow from the compressor outlet and circulate the refrigerant flow in the main loop, (ii) divide the high-pressure refrigerant flow into a first part circulating successively through the first heat exchanger and the fourth expansion valve, and a second part circulating through the fourth bypass branch to the sixth expansion valve, the refrigerant from the fourth expansion valve joining the refrigerant from the sixth expansion valve to form a refrigerant flow, (iii) circulate the refrigerant flow formed successively through the third heat exchanger and the fifth expansion valve, the refrigerant from the fifth expansion valve joining the compressor.

[0007] The high-pressure refrigerant circulating in the first heat exchanger can heat the interior airflow and thus the vehicle passenger compartment. The thermal energy remaining in the refrigerant after heating the interior airflow is generally insufficient to adequately heat the powertrain component. The refrigerant flow rate in the fourth bypass branch increases the energy supplied to the component, thereby increasing the heating capacity. According to the operating mode corresponding to the proposed process, the second heat exchanger is not thermally active and does not evaporate any refrigerant. The passenger compartment and the powertrain component can be heated without risk of icing the second heat exchanger. This operating mode is therefore particularly advantageous at ambient temperatures below 0°C.

[0008] The features listed in the following paragraphs can be implemented independently of each other or in any technically possible combination:

[0009] In steady state, the different steps of the proposed process are: (i) supplying a first flow of high-pressure refrigerant at the compressor outlet and circulating the first flow of refrigerant in the main loop, (ii) dividing the first flow of high-pressure refrigerant into a second flow circulating successively in the first heat exchanger and the fourth expansion valve, and a third flow circulating in the fourth bypass branch towards the sixth expansion valve, the refrigerant from the fourth expansion valve joining the refrigerant from the sixth expansion valve so as to form the first flow of refrigerant, (iii) circulate the first flow of refrigerant successively through the third heat exchanger and the fifth expansion valve, the first flow of refrigerant from the fifth expansion valve joining the compressor.

[0010] According to a first example of implementation of the control process: - in step (ii), the fourth expansion valve reduces the refrigerant from the first heat exchanger to an intermediate pressure lower than the high pressure, and the sixth expansion valve reduces the refrigerant circulating in the fourth bypass branch to the intermediate pressure, and - in step (iii), the fifth expansion valve expands the intermediate pressure refrigerant from the third heat exchanger to a low pressure lower than the intermediate pressure.

[0011] According to this first example of implementing the process, the high-pressure refrigerant circulating in the first heat exchanger heats the interior airflow and thus the vehicle's passenger compartment. The enthalpy of the refrigerant exiting the first heat exchanger is lower than the enthalpy of the refrigerant entering the compressor. Therefore, the thermodynamic cycle performed by the refrigerant passing through the first heat exchanger is not closed. To close the thermodynamic cycle, the intermediate-pressure refrigerant from the fourth bypass branch increases the enthalpy of the refrigerant entering the third heat exchanger. The thermodynamic cycle can thus be closed thanks to the portion of the refrigerant circulating in the fourth bypass branch.

[0012] The different stages of the proposed control process can thus be written, according to the first implementation example and in steady state: (i) provide an initial flow of high-pressure refrigerant from the compressor outlet and circulate the initial flow of refrigerant through the main loop, (ii) divide the first high-pressure refrigerant flow into a second flow circulating successively through the first heat exchanger and the fourth expansion valve, and a third flow circulating through the fourth bypass branch to the sixth expansion valve, to reduce the second flow of refrigerant from the first heat exchanger to an intermediate pressure lower than the high pressure, relaxing the third flow circulating in the fourth bypass branch until the intermediate pressure is reached, The intermediate pressure refrigerant from the first heat exchanger joins the intermediate pressure refrigerant from the fourth branch of the bypass to form the first flow of intermediate pressure refrigerant. (iii) circulate the first flow of intermediate pressure refrigerant through the third heat exchanger, expand the intermediate pressure refrigerant from the third heat exchanger to a low pressure below the intermediate pressure, the low pressure refrigerant joining the compressor.

[0013] According to a second example of implementation of the control method: - in step (ii), the fourth expansion valve reduces the refrigerant from the first heat exchanger to a low pressure, and The sixth expansion valve reduces the refrigerant circulating in the fourth bypass branch to low pressure, and - in step (iii), the low-pressure refrigerant from the third heat exchanger passes through the fifth expansion valve without undergoing expansion.

[0014] According to the second example of implementation of the control method, the flow rate of the internal airflow is preferably less than a predetermined threshold.

[0015] In particular, the flow rate of the internal airflow can be zero.

[0016] In this second embodiment of the process, the high-pressure, high-temperature refrigerant from the compressor is expanded to a low-pressure state before circulating through the third heat exchanger. The low-pressure, high-temperature gaseous refrigerant cools in the third heat exchanger and releases heat. This heats the component of the electric drive system. The low-pressure refrigerant from the third heat exchanger then passes through the fifth expansion valve without a pressure change and returns to the compressor inlet. This cycle is referred to as the low-pressure triangle.

[0017] The different stages of the proposed control process can thus be written, according to the second implementation example and in steady state: (i) provide an initial flow of high-pressure refrigerant from the compressor outlet and circulate the initial flow of refrigerant through the main loop, (ii) divide the first high-pressure refrigerant flow into a second flow circulating successively through the first heat exchanger and the fourth expansion valve, and a third flow circulating through the fourth bypass branch to the sixth expansion valve, to reduce the second flow of refrigerant from the first heat exchanger to a low pressure lower than the high pressure, reducing the third flow circulating in the fourth bypass branch to low pressure, The low-pressure refrigerant from the first heat exchanger joins the low-pressure refrigerant from the fourth branch of the bypass to form the first flow of low-pressure refrigerant. (iii) circulate the first flow of low-pressure refrigerant through the third heat exchanger, the low-pressure refrigerant fluid from the third heat exchanger joining the compressor.

[0018] According to a third example of implementing the control method: - in step (ii), the refrigerant from the first heat exchanger passes through the fourth expansion valve without undergoing expansion, and The refrigerant circulating in the fourth branch of the bypass passes through the sixth expansion valve without undergoing any expansion, and - in step (iii), the fifth expansion valve reduces the high-pressure refrigerant from the third heat exchanger to a low pressure lower than the high pressure.

[0019] According to the third example of implementation of the control method, the flow rate of the internal airflow is preferably lower than the predetermined threshold.

[0020] In particular, the flow rate of the internal airflow can be zero.

[0021] In this third embodiment of the process, the high-pressure, high-temperature refrigerant from the compressor circulates through the third heat exchanger without prior expansion. The high-pressure, high-temperature gaseous refrigerant cools in the third heat exchanger and releases heat. The component of the electric drive system is thus heated. The high-pressure refrigerant from the third heat exchanger is depressurized as it passes through the fifth expansion valve and enters the compressor inlet. This cycle is known as the high-pressure triangle.

[0022] The different stages of the proposed control process can thus be written, according to the third implementation example and in steady state: (i) provide an initial flow of high-pressure refrigerant from the compressor outlet and circulate the initial flow of refrigerant through the main loop, (ii) divide the first high-pressure refrigerant flow into a second flow circulating successively through the first heat exchanger and the fourth expansion valve, and a third flow circulating through the fourth bypass branch to the sixth expansion valve, The high-pressure refrigerant from the first heat exchanger joins the high-pressure refrigerant from the fourth branch of the bypass to form the first high-pressure refrigerant flow. (iii) circulate the first flow of high-pressure refrigerant through the third heat exchanger, expand the intermediate-pressure refrigerant from the third exchanger to a low pressure lower than the high pressure, the low-pressure refrigerant from the third exchanger joining the compressor.

[0023] The refrigerant circuit is configured to circulate a refrigerant.

[0024] The compressor changes the refrigerant fluid from a low pressure state, at the compressor inlet, to a high pressure state, at the compressor outlet.

[0025] According to one embodiment, the first heat exchanger is configured to exchange heat with the airflow inside the vehicle's passenger compartment.

[0026] 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.

[0027] According to the proposed process, the first exchanger can operate as a refrigerant fluid cooler. According to the proposed process, the third exchanger can operate as a refrigerant fluid cooler.

[0028] The third heat exchanger can be used to heat or cool the vehicle's electric powertrain element. The vehicle's electric powertrain element can thus be maintained, or placed, within a preferred temperature range corresponding to its optimal operation.

[0029] The third exchanger can be thermally inactive.

[0030] According to the proposed process, the second exchanger is thermally inactive.

[0031] The fifth connection point is located on the second branch of the bypass downstream of the third exchanger and upstream of the fifth regulator.

[0032] According to one embodiment, the element of the vehicle's electric powertrain includes an electrical energy storage battery.

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

[0034] 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.

[0035] 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.

[0036] Each regulator is, for example, an electronic regulator.

[0037] According to one aspect of the proposed control method, the flow rate of refrigerant fluid in the first bypass branch is zero. The third regulator is thus in the closed position.

[0038] According to another aspect of the proposed control method, the flow rate of refrigerant circulating in the third bypass branch is zero. The first regulator is thus in the closed position. Similarly, the second regulator is in the closed position.

[0039] According to yet another aspect of the proposed control method, the flow rate of refrigerant circulating in the second exchanger is zero. The flow rate of refrigerant circulating in the main loop between the third connection point and the fourth connection point is zero.

[0040] The fourth regulator is in the open position. The fifth regulator is in the open position. The sixth regulator is in the open position.

[0041] The opening position of the fourth regulator may differ from the opening position of the fifth regulator.

[0042] The value of the so-called "high pressure" at the compressor outlet is, for example, between 110 bars and 130 bars. The value of the so-called "intermediate" pressure, after pressure reduction, for example, by the fourth regulator on the one hand and by the sixth regulator on the other, is lower than the high-pressure value. The intermediate pressure is, for example, between 40 bar and 120 bar. The value of the so-called "low pressure", after expansion for example in the second regulator, is lower than the value of the intermediate pressure. Low pressure, for example, is between 35 bars and 65 bars.

[0043] According to one aspect of the proposed control method, the method comprises the steps: - determining a thermal power supplied to the first exchanger, - controlling the flow rate of refrigerant circulating in the refrigerant circuit so as to control the thermal power supplied by the first exchanger to a first target value.

[0044] The control process may include the following substeps: - increase the flow rate of refrigerant circulating in the refrigerant circuit if the thermal power supplied by the first heat exchanger is less than the first target value, and - decrease the flow rate of refrigerant circulating in the refrigerant circuit if the thermal power supplied by the first exchanger is greater than the first target value.

[0045] The flow rate of refrigerant circulating in the refrigerant circuit is equal to the flow rate of refrigerant discharged by the compressor.

[0046] The control process may include the step: - control the compressor rotation speed in order to control the flow of refrigerant circulating in the refrigerant circuit.

[0047] 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.

[0048] According to one embodiment, in which the compressor is an electric compressor, the process comprises the following steps: - determine the electrical power absorbed by the compressor, - control the compressor rotation speed in order to control the electrical power absorbed by the compressor to a second target value. The second target value depends on the high pressure value and depends on the low pressure value.

[0049] The process may include the substep: - determine a value for the adiabatic efficiency of the compressor.

[0050] 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.

[0051] The proposed method may include a substep for determining the compressor rotation speed.

[0052] According to another aspect of the proposed control method, the method comprises the following steps: - determine a value for the pressure of the high-pressure refrigerant fluid, - control a refrigerant expansion in the fourth expansion valve so as to control the high-pressure refrigerant pressure to a third target value.

[0053] The proposed control method may include the following substeps: - reduce the cross-sectional area of ​​the refrigerant flow through the fourth expansion valve if the high-pressure refrigerant pressure exceeds the third target value. - increase the refrigerant flow area through the fourth expansion valve if the high-pressure refrigerant pressure is below the third target value.

[0054] According to yet another aspect of the proposed control method, the method comprises the following steps: - determine a value for the pressure of the low-pressure refrigerant fluid, - control a refrigerant expansion in the sixth expansion valve so as to control the low-pressure refrigerant pressure to a fourth target value.

[0055] The control process may include the following substeps: - reduce the cross-sectional area of ​​the refrigerant flow through the sixth expansion valve if the low-pressure refrigerant flow is higher than the fourth target value. - increase the refrigerant flow area through the sixth expansion valve if the low-pressure refrigerant is below the fourth target value.

[0056] According to one embodiment, in which the third heat exchanger is thermally coupled with the element of the vehicle's electric powertrain via a heat transfer fluid that can circulate in a heat transfer fluid circuit, the flow rate of heat transfer fluid in the third exchanger is less than a predetermined threshold.

[0057] The flow rate of the heat transfer fluid circulating in the third heat exchanger is zero. In this case, the heat exchange in the third heat exchanger is zero. All the heating power is thus dissipated in the first heat exchanger. In other words, all the heating power is allocated to the passenger compartment.

[0058] 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 expansion valve, — a second expansion valve, — 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 heat exchanger and the first pressure regulator to a fourth connection point located on the main loop downstream of the second exchanger and upstream of the accumulation device, the second branch of the bypass successively comprising a fourth expansion valve, a third heat exchanger thermally coupled with an element of an electric traction chain of a motor vehicle, and a fifth expansion valve, - 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.

[0059] 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.

[0060] The internal exchanger is configured to allow heat exchange between the refrigerant circulating between the first expansion valve and the sixth connection point 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. 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.

[0062] 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 successively comprising a seventh expansion valve and a fourth heat exchanger configured to exchange heat with an internal airflow.

[0063] The main loop includes a first shut-off valve disposed between the first connection point and the seventh connection point.

[0064] The main loop includes a second shut-off valve disposed between the second connection point and the fourth connection point.

[0065] The main loop includes a second shut-off valve disposed between the second connection point and the tenth connection point.

[0066] The first shut-off valve is an electrically operated valve. Similarly, the second shut-off valve is an electrically operated valve.

[0067] The refrigerant circuit includes a first one-way valve disposed on the main loop between the first exchanger and the third connection point.

[0068] 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.

[0069] The refrigerant circuit includes a second one-way valve disposed on the third branch of the bypass.

[0070] 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.

[0071] The refrigerant circuit includes a third one-way valve disposed on the main loop between the fourth exchanger and the tenth connection point.

[0072] 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.

[0073] 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.

[0074] The first one-way valve is, for example, a non-return valve.

[0075] Similarly, the second one-way valve and the third one-way valve can also be a check valve.

[0076] Alternatively, each one-way valve can be an electrically operated valve.

[0077] The disclosure also relates to a computer program stored in memory and configured to implement the process described above. Brief description of the drawings

[0078] Other features, details and advantages will become apparent upon reading the detailed description below, and upon analysis of the accompanying drawings, on which:

[0079] [Fig. 1] is a schematic view of a thermal conditioning system according to a first embodiment of the invention,

[0080] [Fig.2] is a schematic view of a thermal conditioning system according to a second embodiment of the invention,

[0081] [Fig.3] is a schematic view illustrating the operation of the system of thermal conditioning of [Fig.2], according to a first example of implementation of the proposed process,

[0082] [Fig.4] is a schematic view illustrating the operation of the system of thermal conditioning of [Fig.2], according to a second or third example of implementation of the proposed process,

[0083] [Fig.5] is a diagram illustrating the operation of the system of thermal conditioning of [Fig.2], comparing the first, second and third examples of implementation of the proposed process,

[0084] [Fig.6] is a block diagram of the proposed process. Description of the implementation methods

[0085] To facilitate reading the figures, the various elements are not necessarily drawn to scale. In these figures, identical elements bear the same reference numerals. Certain elements or parameters may be indexed, that is, designated, for example, as first element or second element, or first parameter and second parameter, etc. This indexing aims to differentiate similar, but not identical, elements or parameters. This indexing does not imply a priority of one element or parameter over another, and the designations may be interchanged.

[0086] 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" This 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.

[0087] 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.

[0088] When it is specified that a subsystem includes a given element, this does not exclude the presence of other elements in that subsystem.

[0089] The thermal conditioning system 100, which will be described below, includes an electronic control unit 64 that receives information from various sensors measuring, in particular, the characteristics of the refrigerant at various points in the circuit. The electronic control unit 64 also receives instructions from the vehicle occupants, for example, the desired temperature inside the passenger compartment. The electronic control unit 64 can also receive instructions from other electronic subsystems, such as a battery management system for electrical energy storage. The electronic control unit 64 implements control laws to operate the various actuators, in order to control the thermal conditioning system 100 and ensure compliance with the received instructions. The control unit 64 can execute software encoding the proposed process.

[0090] 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. An electronic unit controls the electric current supplied to the different windings of the electric motor of compressor 7. The electric motor of compressor 7 is, for example, a brushless motor.

[0091] 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.

[0092] 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.

[0093] 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.

[0094] 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.

[0095] 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 external airflow Fe if necessary. The airflow provided by 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 thermal conditioning system 100.

[0096] The term "first exchanger" is equivalent to the term "first exchanger of heat.” 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.”

[0097] 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.

[0098] Figure [Fig.1] shows a thermal conditioning system 100 for a motor vehicle. 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 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 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 comprising successively a fourth expansion valve 34, a third heat exchanger 3 thermally coupled with an element 25 of an electric traction chain of a motor vehicle, and a fifth expansion valve 35. The refrigerant circuit 10 has a third branch D connecting to a fifth connection point 15 located on the second branch of bypass C downstream of the third exchanger 3 and upstream of the fourth connection point 14 to a sixth connection point 16 arranged on the main loop A between the first regulator 31 and the second regulator 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 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 exchanger 3, the fourth branch E including a fifth expansion valve 35. The thermal conditioning system 100 includes an electronic control unit 64 configured to implement the process described below.

[0099] A computer program stored in memory can implement the proposed process. The memory can be integrated into the electronic control unit 64.

[0100] 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.

[0101] The thermal coupling between the first heat exchanger 1 and the internal airflow Fi can be achieved in different ways.

[0102] 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.

[0103] 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.

[0104] 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, the heat transfer fluid circuit comprising a heat exchanger IA configured to exchange heat with the interior airflow Fi to the vehicle's passenger compartment.

[0105] The second heat exchanger 2 is, for example, located at the front of the vehicle so as to receive the outside airflow directly. The second heat exchanger 2 can be located just behind the vehicle's grille.

[0106] According to the example illustrated in the various figures, the third heat exchanger 3 is thermally coupled with the element 25 of the electric traction chain by means of a heat transfer fluid circulating in a heat transfer fluid circuit 40. 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 circuit 40. When the pump is inactive, the heat transfer fluid does not circulate in circuit 40, and the flow rate in circuit 40 is zero. The pump is, for example, an electrically driven pump. 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 component 25 of the vehicle's electric powertrain. The heat transfer fluid thus enables heat transfer between the refrigerant and the component 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.

[0107] The heat transfer fluid circulating in the circuit 40 is, for example, a mixture of water and glycol. According to the illustrated example, circuit 30 and circuit 40 are independent, that is to say, they are not connected.

[0108] According to one embodiment, element 25 of the vehicle's electric drive chain includes an electrical energy storage battery. In one variant, or additionally, element 25 of the vehicle's electric drivetrain includes a vehicle electric traction motor. In another variant, or additionally, element 25 of the vehicle's electric drivetrain includes an electronic control unit for the vehicle's electric traction motor.

[0109] 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 electronic control unit of the electric motor. The heat transfer fluid can thus exchange heat.

[0110] 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 fifth regulator 35.

[0111] 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.

[0112] In this second embodiment, the thermal conditioning system 100 includes 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.

[0113] The internal exchanger 6 is configured to allow heat exchange between the refrigerant circulating between the first expansion valve 31 and the sixth connection point 16 and the refrigerant downstream of the accumulation device 8 and upstream of an inlet 7a of the compressor 7.

[0114] According to the second embodiment, the thermal conditioning system 100 includes 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 indoor airflow Fi.

[0115] The fourth heat exchanger 4 is disposed in the vehicle's heating, ventilation and / or air conditioning system. According to the first embodiment, the fourth exchanger 4 is arranged upstream of the exchanger IA in a direction of flow of the internal air flow Fi. According to the second embodiment, the fourth exchanger 4 is arranged upstream of the first exchanger 1 in a direction of flow of the internal air flow Fi. The fourth exchanger 4 allows the interior airflow Fi to be cooled and thus the passenger compartment of the vehicle.

[0116] 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 the fifth branch F but not include the internal exchanger 6, and vice versa.

[0117] 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.

[0118] The main loop A includes a first shut-off valve 41 disposed between the first connection point 11 and the seventh connection point 17.

[0119] 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.

[0120] 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 64.

[0121] 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.

[0122] 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.

[0123] 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.

[0124] 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. 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.

[0125] 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. Alternatively, each one-way valve 43, 44, 45 can be an electrically operated valve.

[0126] Each regulator 31, ..., 36 is for example an electronic regulator.

[0127] The thermal conditioning system 100 can operate in several modes. The proposed method, when implemented, corresponds to specific operating modes of the thermal conditioning system 100.

[0128] 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 compressor 7, — 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, - 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 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, a third heat exchanger 3 thermally coupled with an element 25 of an electric traction chain of a motor vehicle, and a fifth expansion valve 35, - a third branch D connecting a fifth connection point 15 located on the second branch C downstream of the third heat exchanger 3 and upstream of the fourth connection point 14 to a sixth connection point 16 arranged 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 sixth regulator 36. The process involves the following steps: (i) supply a flow rate D of high-pressure refrigerant at the outlet of compressor 7 and circulate the flow rate D of refrigerant in the main loop A, (ii) divide the flow D of high-pressure refrigerant into a first part PI circulating successively in the first exchanger 1 and the fourth expansion valve 34, and a second part P2 circulating in the fourth bypass branch E towards the sixth expansion valve 36, the refrigerant from the fourth expansion valve 34 joining the refrigerant from the sixth expansion valve 36 so as to form a flow D' of refrigerant, (iii) circulating the flow rate D' of refrigerant formed successively in the third heat exchanger 3 and in the fifth expansion valve 35, the refrigerant from the fifth expansion valve 35 returning to the compressor 7.

[0129] The high-pressure refrigerant circulating in the first heat exchanger 1 can heat the interior airflow Fi and thus the vehicle passenger compartment. The thermal energy remaining in the refrigerant after heating the interior airflow Fi is generally insufficient to provide adequate heating for the powertrain component 25. The refrigerant flow rate circulating in the fourth bypass branch E increases the energy supplied to the component 25, and thus increases the heating capacity. According to the operating mode corresponding to the proposed process, the second heat exchanger 2 is not thermally active and does not evaporate any refrigerant.The passenger compartment and element 25 of the traction chain can thus be heated without risk of icing the second heat exchanger 2. This operating mode is therefore particularly advantageous in cold ambient temperatures, especially below 0°C.

[0130] The second part P2 of the high-pressure refrigerant flow D is complementary to the first part PI of the high-pressure refrigerant flow D.

[0131] According to the proposed process, the first exchanger 1 can operate as a refrigerant fluid cooler. In other words, the refrigerant can release heat as it passes through the first exchanger 1. According to the proposed process, the third exchanger 3 can operate as a refrigerant fluid cooler. As before, the refrigerant can, under certain operating conditions, release heat as it passes through the third exchanger 3. According to the proposed process, the second exchanger 2 is thermally inactive. According to the proposed process, the refrigerant flow rate in the second heat exchanger 2 is zero. In other words, the refrigerant does not circulate in the second heat exchanger 2. Therefore, there is no heat exchange at the level of the second exchanger 2. The third heat exchanger 3 can be thermally inactive. In other words, the refrigerant may, under certain operating conditions, not perform any heat exchange as it passes through the third heat exchanger 3.

[0132] 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 E downstream of the sixth expansion valve 36 is equal to the refrigerant flow rate circulating in the fourth branch E upstream of the sixth expansion valve 36. In steady state, the flow rate D' drawn in by the compressor 7 is identical to the flow rate D discharged by the compressor 7.

[0133] Thus, in steady state the different stages of the proposed process are: (i) supplying a first flow Q1 of high-pressure refrigerant at the outlet of the compressor 7 and circulating the first flow Q1 of refrigerant in the main loop A, (ii) divide the first flow Q1 of high-pressure refrigerant into a second flow Q2 circulating successively in the first exchanger 1 and the fourth expansion valve 34, and a third flow Q3 circulating in the fourth bypass branch E towards the sixth expansion valve 36, the refrigerant from the fourth expansion valve 34 joining the refrigerant from the sixth expansion valve 36 so as to form the first flow Q1 of refrigerant, (iii) circulate the first flow Q1 of refrigerant successively through the third heat exchanger 3 and the fifth expansion valve 35, the first flow Q1 of refrigerant from the fifth expansion valve 35 joining the compressor 7.

[0134] Figures 3 and 4 illustrate the circulation of the refrigerant in the circuit 10 when the proposed process is implemented. Figure 3 corresponds to a first example of implementation. Figure 4 corresponds to a second and a third example. In these figures, 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.

[0135] Fig. 5 schematically illustrates the value of the refrigerant fluid pressure at different points in the circuit. 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.

[0136] A first example of implementation of the control process allows for heating of the vehicle's passenger compartment.

[0137] According to the first example of implementation of the control method: - in step (ii), the fourth expansion valve 34 reduces the refrigerant from the first heat exchanger 1 to an intermediate pressure lower than the high pressure, and The sixth expansion valve 36 expands the refrigerant circulating in the fourth bypass branch E to the intermediate pressure, and - in step (iii), the fifth expansion valve 35 expands the intermediate pressure refrigerant fluid from the third heat exchanger 3 to a low pressure lower than the intermediate pressure.

[0138] According to this first example of implementation of the process, illustrated in [Fig.3], the high-pressure refrigerant circulating in the first exchanger 1 makes it possible to heat the interior airflow Fi and thus the passenger compartment of the vehicle. The enthalpy of the refrigerant exiting the first heat exchanger 1 is lower than the enthalpy of the refrigerant entering the compressor 7. Therefore, the thermodynamic cycle performed by the refrigerant passing through the first heat exchanger 1 is not complete. To complete the thermodynamic cycle, the intermediate-pressure refrigerant from the fourth branch E increases the enthalpy of the refrigerant entering the third heat exchanger 3. The thermodynamic cycle is thus completed thanks to the enthalpy provided by the refrigerant circulating in the fourth branch E.

[0139] According to the first example of implementation of the process, during steady-state operation, the different steps of the proposed process can be written as follows: (i) provide a first flow Q1 of high-pressure refrigerant at the outlet of compressor 7 and circulate the first flow Q1 of refrigerant in the main loop A, (ii) divide the first flow Q1 of high-pressure refrigerant into a second flow Q2 circulating successively in the first exchanger 1 and the fourth expansion valve 34, and a third flow Q3 circulating in the fourth bypass branch E towards the sixth expansion valve 36, reduce the second flow Q2 of refrigerant from the first exchanger 1 to an intermediate pressure lower than the high pressure, reduce the third flow Q3 circulating in the fourth branch E to the intermediate pressure, the intermediate pressure refrigerant from the first exchanger 1 joining the intermediate pressure refrigerant from the fourth branch E to form the first intermediate pressure refrigerant flow Q1, (iii) circulate the first flow Q1 of intermediate pressure refrigerant through the third heat exchanger 3, expand the intermediate pressure refrigerant from the third heat exchanger 3 to a low pressure lower than the intermediate pressure, the low pressure refrigerant joining the compressor 7.

[0140] Part A of [Fig.5] illustrates the level of relaxation ensured respectively by the fourth regulator 34, the sixth regulator 36 and the fifth regulator 35, during operation according to the first example of implementation of the process.

[0141] A second example of implementation of the control method allows heating of element 25 of the vehicle's electric traction chain.

[0142] According to the second example of implementation of the control method: - in step (ii), the fourth expansion valve 34 reduces the refrigerant from the first heat exchanger 1 to a low pressure, and The sixth expansion valve 36 reduces the refrigerant circulating in the fourth branch of the bypass E to low pressure, and - at step (iii), the low-pressure refrigerant fluid from the third heat exchanger 3 passes through the fifth expansion valve 35 without undergoing expansion.

[0143] According to the second example of implementing the control method, the indoor air flow rate Fi is preferably less than a predetermined threshold. The predetermined threshold is, for example, 50 kg / h (kilograms per hour). In particular, the indoor air flow rate Fi can be zero.

[0144] In this second embodiment of the process, the high-pressure, high-temperature refrigerant from the compressor 7 is expanded to a low-pressure state before flowing through the third heat exchanger 3. The low-pressure, high-temperature gaseous refrigerant cools in the third heat exchanger 3 and releases heat. The element 25 of the electric drive chain is thus heated. After passing through the third heat exchanger 3, the low-pressure refrigerant flows through the fifth expansion valve 5 without a pressure change and enters the inlet 7a of the compressor 7. This thermodynamic cycle is referred to as the low-pressure triangle.

[0145] According to the second example of implementation of the process, during steady-state operation, the various steps of the proposed control process are written as follows: (i) supply a first flow Q1 of high-pressure refrigerant at the outlet of the compressor 7 and circulate the first flow Q1 of refrigerant in the main loop A, (ii) divide the first flow Q1 of high-pressure refrigerant into a second flow Q2 circulating successively in the first heat exchanger 1 and the fourth expansion valve 34, and a third flow Q3 circulating in the fourth bypass branch E to the sixth expansion valve 36, reduce the second flow Q2 of refrigerant from the first heat exchanger 1 to a low pressure lower than the high pressure, reduce the third flow Q3 circulating in the fourth bypass branch E to the low pressure, the low-pressure refrigerant from the first heat exchanger 1 joining the low-pressure refrigerant from the fourth branch E so as to form the first flow Q1 of low-pressure refrigerant, (iii) circulating the first flow Q1 of low-pressure refrigerant in the third heat exchanger 3, the low-pressure refrigerant fluid from the third exchanger 3 joining the compressor 7.

[0146] Part B of [Fig.5] illustrates the level of relaxation ensured respectively by the fourth regulator 34, the sixth regulator 36 and the fifth regulator 3, during operation according to the second example of implementation of the process.

[0147] A third example of implementation of the control method also makes it possible to heat element 25 of the vehicle's electric traction chain.

[0148] According to the third example of implementation of the control method: - in step (ii), the refrigerant from the first heat exchanger 1 passes through the fourth expansion valve 34 without undergoing any expansion, and The refrigerant circulating in the fourth branch of the bypass E passes through the sixth expansion valve 36 without undergoing any expansion, and - in step (iii), the fifth expansion valve 35 expands the high-pressure refrigerant fluid from the third heat exchanger 3 to a low pressure lower than the high pressure.

[0149] According to the third example of implementation of the control method, an indoor air flow rate Fi is preferably lower than the predetermined threshold.

[0150] In particular, the flow rate of the internal airflow Fi can be zero.

[0151] In this third example of implementing the process, the high-pressure, high-temperature refrigerant from the compressor 7 circulates in the third heat exchanger 3 without prior expansion. The high-pressure, high-temperature gaseous refrigerant cools in the third heat exchanger 3 and releases heat. The element 25 of the electric drive chain is thus heated. The high-pressure refrigerant from the third exchanger 3 flows in the second branch of bypass C to the fifth expansion valve 35 and passes to low pressure by passing through the fifth expansion valve 5. The low-pressure refrigerant flows successively through the accumulator 8, through the internal exchanger 6, and reaches the inlet 7a of the compressor 7. This cycle is referred to as the high-pressure triangle.

[0152] According to the third example of implementation of the process, the different steps of the proposed control process are written during steady-state operation: (i) provide a first flow Q1 of high-pressure refrigerant at the outlet of compressor 7 and circulate the first flow Q1 of refrigerant in the main loop A, (ii) divide the first flow Q1 of high-pressure refrigerant into a second flow Q2 circulating successively in the first exchanger 1 and the fourth expansion valve 34, and a third flow Q3 circulating in the fourth branch of bypass E to the sixth expansion valve 36, the high-pressure refrigerant from the first exchanger 1 joining the high-pressure refrigerant from the fourth branch of bypass E so as to form the first flow Q1 of high-pressure refrigerant, (iii) circulate the first flow Q1 of high-pressure refrigerant in the third heat exchanger 3, expand the intermediate-pressure refrigerant from the third exchanger 3 to a low pressure lower than the high pressure, the low-pressure refrigerant from the third exchanger 3 joining the compressor 7.

[0153] Part C of [Fig.5] illustrates the level of relaxation ensured respectively by the fourth regulator 34, the sixth regulator 36 and the fifth regulator 35, during operation according to the third example of implementation of the process.

[0154] According to the first example of implementation of the process: - the first exchanger 1 operates as a refrigerant fluid cooler, - the third exchanger 3 is thermally inactive.

[0155] According to the second and third implementation examples of the process: - the first exchanger 1 is thermally inactive. - the third exchanger 3 operates as a refrigerant fluid cooler.

[0156] According to the proposed process, the second exchanger 2 is thermally inactive. In other words, depending on the operating principle corresponding to the first, second, or third example, the second heat exchanger 2 does not participate in heat exchange. Similarly, the fourth heat exchanger 4 is thermally inactive, since it does not receive a flow of refrigerant. The internal exchanger 6 does not participate in heat exchange either, since the first heat exchange section 6a is not traversed by a flow of refrigerant fluid.

[0157] When the proposed process is implemented, the flow rate of refrigerant fluid in the first branch of bypass B is zero. The third regulator 33 is thus in the closed position. Similarly, the flow rate of refrigerant circulating in the third branch of the bypass D is zero. The first regulator 31 is thus in the closed position. The second regulator 32 is also in the closed position. Similarly, the refrigerant flow rate in the second heat exchanger 2 is zero. The refrigerant flow rate in the main loop A between the third connection point 13 and the fourth connection point 16 is zero.

[0158] The fourth regulator 34 is in the open position. The opening of the fourth regulator 34 can be partial or total. The fifth regulator 35 is in the open position. The opening of the fifth regulator 35 can be partial or total. The sixth regulator 36 is in the open position. The opening of the sixth regulator 36 can be partial or total. The opening position of the fourth regulator 34 may differ from the opening position of the fifth regulator 35.

[0159] According to the first example of implementation of the process: The value of the so-called "high pressure", at the outlet of compressor 7, is for example between 110 bars and 130 bars. The value of the so-called "intermediate" pressure, after expansion for example by the fourth regulator 34 on the one hand, and by the sixth regulator 36 on the other, is lower than the value of the high pressure. The intermediate pressure is, for example, between 40 bar and 120 bar. The value of the so-called "low pressure," after expansion for example in the second regulator 32, is lower than the value of the intermediate pressure. The low pressure is, for example, between 35 bar and 65 bar.

[0160] We will now describe various aspects of the control methods used when the process according to the first example is implemented. According to this first example, the passenger compartment is heated.

[0161] The proposed control method comprises the following steps: - determine a thermal power Pwl supplied to the first exchanger 1, - control the flow rate D of refrigerant circulating in the refrigerant circuit 10 so as to control the thermal power Pwl supplied by the first exchanger 1 to a first target value.

[0162] When the heat couple between the first heat exchanger 1 and the indoor airflow is direct, the heat power Pwl supplied by the first heat exchanger 1 is determined from a value of the flow rate of the indoor airflow Fi and a value of the temperature increase of the indoor airflow Fi during the passage through the first heat exchanger 1. When the heat couple between the first heat exchanger 1 and the indoor airflow is indirect, the flow rate of the indoor airflow Fi and the temperature increase are those occurring during the passage through the heat exchanger IA.

[0163] The control process comprises the following substeps: - increase the flow rate D of refrigerant circulating in the refrigerant circuit 10 if the thermal power Pwl supplied by the first heat exchanger 1 is less than the first target value, and - decrease the flow rate Q1 of refrigerant circulating in the refrigerant circuit 10 if the thermal power Pwl supplied by the first exchanger 1 is greater than the first target value.

[0164] The flow rate of refrigerant circulating in the refrigerant circuit 10 is equal to the flow rate of refrigerant discharged by the compressor 7.

[0165] The flow rate of refrigerant discharged by the compressor 7 depends on the rotational speed, or rotational speed, of the compressor 7. The control process therefore includes the following step: - control the rotation speed of compressor 7 in order to control the flow of refrigerant circulating in the refrigerant circuit 10.

[0166] The control process comprises the following substeps: - increase the rotational speed of compressor 7 in order to increase the flow rate D of refrigerant circulating in the refrigerant circuit 10, and - reduce the rotation speed of compressor 7 so as to reduce the flow rate D of refrigerant circulating in the refrigerant circuit 10.

[0167] According to the illustrated example in which compressor 7 is an electric compressor, the process comprises the following steps: - determine the 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. The second target value depends on the high pressure value and depends on the low pressure value.

[0168] The process may include the substep: - determine a value for the adiabatic efficiency of compressor 7.

[0169] 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.

[0170] The value of the adiabatic efficiency of the compressor 7 is determined for example from the rotational regime of the compressor 7 and from a flow rate circulating in the compressor 7. The adiabatic efficiency value of compressor 7 is, for example, read from a two-input variable map. One input variable is the rotational speed of compressor 7, and the other input variable is the flow rate through compressor 7. Correction terms to account for other parameters can be added. The value of the adiabatic efficiency of compressor 7 is greater than 0.90, for example equal to 0.95.

[0171] The proposed method includes a substep for determining the rotational speed of the compressor 7.

[0172] According to another aspect of the proposed control method, the method comprises the following steps: - determine a value of the PI pressure of the high-pressure refrigerant, - control an expansion of the refrigerant in the fourth expansion valve 34 so as to control the PI pressure of the high-pressure refrigerant 10 to a third target value.

[0173] The proposed control method comprises the following substeps: - decrease the cross-sectional area of ​​the refrigerant flow through the fourth expansion valve 34 if the pressure PI of the high-pressure refrigerant 10 is greater than the third target value, - increase a refrigerant passage section through the fourth expansion valve 34 if the PI pressure of the high-pressure refrigerant 10 is less than the third target value.

[0174] According to another aspect, the process comprises the following steps: - determine a value of the pressure P8 of the low pressure refrigerant, - control an expansion of the refrigerant in the sixth expansion valve 36 so as to control the pressure P8 of the low pressure refrigerant 10 to a fourth target value.

[0175] The control process comprises the following substeps: - decrease the cross-sectional area of ​​the refrigerant flow through the sixth expansion valve 36 if the pressure P8 of the low-pressure refrigerant 10 is greater than the fourth target value, - increase a refrigerant passage section through the sixth expansion valve 36 if the pressure P8 of the low-pressure refrigerant 10 is less than the fourth target value.

[0176] According to the illustrated example, 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. According to the first example of implementation of the process, the flow rate QL of heat transfer fluid in the third exchanger 3 is less than a predetermined threshold.

[0177] In other words, the flow rate of heat transfer fluid circulating in the third exchanger 3 is very low so as to limit the heat exchange in the third exchanger 3 as much as possible. The flow rate QL of heat transfer fluid circulating in the third exchanger 3 is, for example, zero. In this case, the heat exchange in the third heat exchanger 3 is zero. All the heating power is thus dissipated in the first heat exchanger 1. In other words, all the heating power supplied by the climate control system is dedicated to the passenger compartment. According to the illustrated example, the flow rate of heat transfer fluid in circuit 40 is zero. Therefore, the circulation pump for circuit 40 is kept off. In the case not shown, where circuit 40 has several parallel circulation branches, circulation in the branch containing the third heat exchanger 3 can be stopped by a shut-off valve.

[0178] The process includes a substep: - determine a flow rate QL of heat transfer fluid circulating in the heat transfer fluid circuit 40.

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 outside airflow (Fe) to the vehicle's passenger compartment, — a refrigerant fluid 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 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 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 branch (C) comprising successively a fourth expansion valve (34), a third heat exchanger (3) thermally coupled with an element (25) of an electric traction chain of a motor vehicle, and a fifth expansion valve (35), - 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 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 sixth expansion valve (36), the process comprising the steps: (i) supplying a flow rate (Q) of high-pressure refrigerant at the outlet of the compressor (7) and circulating the flow rate (Q) of refrigerant in the main loop (A), (ii) dividing the flow rate (Q) of high-pressure refrigerant into a first part (Q1) circulating successively in the first heat exchanger (1) and the fourth expansion valve (34), and a second part (Q2) circulating in the fourth branch (E) towards the sixth expansion valve (36),the refrigerant from the fourth expansion valve (34) joining the refrigerant from the sixth expansion valve (36) so as to form a flow (D') of refrigerant, (iii) circulating the flow (D') of refrigerant formed successively in the third heat exchanger (3) and in the fifth expansion valve (35), the refrigerant from the fifth expansion valve (35) joining the compressor (7).

2. A control method according to claim 1, wherein: - in step (ii), the fourth expansion valve (34) expands the refrigerant from the first heat exchanger (1) to an intermediate pressure lower than the high pressure, and the sixth expansion valve (36) expands the refrigerant circulating in the fourth bypass branch (E) to the intermediate pressure, and - in step (iii), the fifth expansion valve (35) expands the intermediate pressure refrigerant from the third heat exchanger (3) to a low pressure lower than the intermediate pressure.

3. A control method according to claim 1, wherein: - in step (ii), the fourth expansion valve (34) expands the refrigerant from the first exchanger (1) to a low pressure, and the sixth expansion valve (36) expands the refrigerant circulating in the fourth bypass branch (E) to a low pressure, and - in step (iii), the low-pressure refrigerant from the third heat exchanger (3) passes through the fifth expansion valve (35) without undergoing expansion.

4. A control method according to claim 1, wherein: - in step (ii), the refrigerant from the first exchanger (1) passes through the fourth expansion valve (34) without undergoing expansion, and the refrigerant circulating in the fourth bypass branch (E) passes through the sixth expansion valve (36) without undergoing expansion, and - in step (iii), the fifth expansion valve (35) expands the high-pressure refrigerant from the third heat exchanger (3) to a low pressure lower than the high pressure.

5. A control method according to any one of the preceding claims, wherein: - the flow rate of refrigerant in the first branch of bypass (B) is zero, - the flow rate of refrigerant circulating in the third branch of bypass (D) is zero, and - the flow rate of refrigerant circulating in the second exchanger (2) is zero.

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

7. A control method according to the preceding claim, comprising the substeps: - increasing the flow rate (Q) of refrigerant circulating in the refrigerant circuit (10) if the thermal power (Pwl) supplied by the first heat exchanger (1) is less than the first target value, and - decrease the flow rate (Ql) of refrigerant circulating in the refrigerant circuit (10) if the thermal power (Pwl) supplied by the first exchanger (1) is greater than the first target value.

8. A control method according to any one of the preceding claims, comprising the step: - controlling the rotation speed of the compressor (7) in order to control the flow rate of refrigerant circulating in the refrigerant circuit (10).

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

10. 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, - controlling an expansion of the refrigerant in the fourth expansion valve (34) so ​​as to control the pressure (PI) of the high-pressure refrigerant (10) to a third target value.

11. A control method according to the preceding claim, comprising the substeps: - decreasing a cross-section of the refrigerant through the fourth expansion valve (34) if the pressure (PI) of the high-pressure refrigerant (10) is greater than the third target value, - increasing a cross-section of the refrigerant through the fourth expansion valve (34) if the pressure (PI) of the high-pressure refrigerant (10) is less than the third target value.

12. A control method according to any one of the preceding claims, comprising the steps: - determining a value of the pressure (P8) of the low-pressure refrigerant, - controlling an expansion of the refrigerant in the sixth expansion valve (36) so as to control the pressure (P8) of the low-pressure refrigerant (10) to a fourth target value.

13. A control method according to the preceding claim, comprising the substeps: - decreasing a cross-section of the refrigerant through the sixth expansion valve (36) if the pressure (P8) of the low-pressure refrigerant (10) is greater than the fourth target value, - increasing a cross-section of the refrigerant through the sixth expansion valve (36) if the pressure (P8) of the low-pressure refrigerant (10) is less than the fourth target value.

14. A control method according to the preceding claim, 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.

15. 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) disposed 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), a third heat exchanger (3) thermally coupled with an element (25) of an electric traction chain of a motor vehicle, and a fifth expansion valve (35), - 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 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), - an electronic control unit (64) configured to implement the process according to any one of the preceding claims, - an internal heat exchanger (6) configured to allow heat exchange between the refrigerant circulating between the first expansion valve (31) and the second expansion valve (32) and the refrigerant downstream of the storage device (8) and upstream of an inlet (7a) of the compressor (7), - 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).

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

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