Method for controlling a refrigerant fluid circuit intended for temperature control of a passenger compartment, in particular of a motor vehicle

Abstract

The invention relates to a method for controlling temperature control of a passenger compartment, in particular of a motor vehicle, using a temperature control system, the system comprising a refrigerant fluid circuit, the circuit being configured to perform a thermodynamic cycle, the circuit comprising a first branch and a second branch which extend in parallel, the first branch being intended for heat exchange with a first heat transfer fluid, the second branch being intended for heat exchange with a second heat transfer fluid, the circuit being configured to alternately supply the first branch only, according to a first operating mode, referred to as the simple dehumidification operating mode (100), making it possible to dehumidify the passenger compartment via the first heat transfer fluid, and the first and second branches simultaneously, according to a second operating mode, referred to as the parallel dehumidification operating mode (102), making it possible to dehumidify the passenger compartment via the first heat transfer fluid and to draw heat energy from the second heat transfer fluid, the system being configured to supply a temperature control fluid to the passenger compartment using a mixture of an external air flow and an air flow coming from the passenger compartment, according to a supply mode, referred to as the recirculation supply mode, the method comprising a step of determining an operating mode from among the simple and parallel dehumidification modes (100, 102) such that the determined operating mode takes place, depending on the conditions, at least in the recirculation supply mode.

Description

[0001] DESCRIPTION

[0002] TITLE: Method for controlling a refrigerant circuit intended for the thermoregulation of a passenger compartment, in particular a motor vehicle

[0003] The invention relates to a method for controlling a refrigerant circuit intended for the thermoregulation of a passenger compartment, in particular a passenger compartment of a motor vehicle.

[0004] In this field, it is known to thermoregulate a passenger compartment using a refrigerant circuit operating according to a thermodynamic cycle, in heat pump or air conditioning mode. The refrigerant exchanges heat with an air flow intended to enter the passenger compartment. By heating or cooling said air flow using the refrigerant, it is thus possible to heat or cool the passenger compartment.

[0005] Furthermore, in the event of fogging and / or frost on the windows of the passenger compartment, particularly the windshield, the heat exchange provides dry and, if necessary, hot air to be projected onto the windows to demist and / or defrost them. Similarly, if the air used to generate said air flow is too high in humidity, the heat exchange allows it to be dried before being projected into the passenger compartment. It is thus known to control a refrigerant circuit to dehumidify the air flow with which the refrigerant is intended to exchange heat.

[0006] For this purpose, refrigerant circuits have already been proposed comprising a first branch and a second branch, extending in parallel. Said first branch is intended for heat exchange with the air flow to the passenger compartment and said second branch is intended for heat exchange with an external air flow. Said circuit is configured to alternately supply said first branch only, according to a first operating mode, called simple dehumidification, allowing dehumidification of the passenger compartment, and said first and second branches simultaneously, according to a second operating mode, called parallel dehumidification, allowing dehumidification of the passenger compartment and taking calories from the external air flow.The calories taken from the external air flow make it possible to heat the air flow to the passenger compartment even more, after drying it, than in a simple dehumidification mode.

[0007] It is also known to generate the air flow to the passenger compartment, either solely using an outside air flow, or using a mixture of said outside air flow and an air flow from the passenger compartment, according to a supply mode, known as with recirculation.

[0008] The recirculating supply mode has the advantage of improving energy performance. However, it is seen as presenting risks if the aim is to demist and / or defrost.

[0009] The invention aims to at least partially overcome the above drawbacks and to this end proposes a method for controlling thermoregulation of a passenger compartment, in particular of a motor vehicle, using a thermoregulation system, said system comprising a refrigerant circuit, said circuit being configured to carry out a thermodynamic cycle, said circuit comprising a first branch and a second branch, extending in parallel, said first branch being intended for heat exchange with a first heat transfer fluid, said second branch being intended for heat exchange with a second heat transfer fluid, said circuit being configured to alternately supply said first branch only, according to a first operating mode, called simple dehumidification, allowing dehumidification of the passenger compartment by means of the first heat transfer fluid, and said first and second branches simultaneously,according to a second operating mode, called parallel dehumidification, making it possible to dehumidify the passenger compartment via the first heat transfer fluid and to take calories from the second heat transfer fluid, said system being configured for supplying a thermoregulation fluid to the passenger compartment using a mixture of an outside air flow and an air flow coming from the passenger compartment, according to a supply mode, called with recirculation, said method comprising a step of determining an operating mode from among the simple and parallel dehumidification modes so that the determined operating mode occurs, under certain conditions, at least in supply mode with recirculation. The invention is based on the observation made by the applicant that dehumidification of the air is possible, even in the case of recirculation. What is more, according to the method according to the invention,air recirculation can take place in a wide range of situations, while achieving dehumidification, by exploiting various dehumidification strategies and by determining the strategy to be used taking into account the conditions of use, in particular a heating setpoint for the passenger compartment. The invention thus allows a significant gain in energy efficiency through wider use of air recirculation.,

[0010] According to various additional characteristics of the invention, which may be taken together or separately and which form as many embodiments of the invention:

[0011] - said step of determining the operating mode provides for a switch from the parallel dehumidification mode to the simple dehumidification mode if a temperature, called upstream, of the mixture of the outside air flow and the air flow coming from the passenger compartment is higher than a limit temperature,

[0012] - said step of determining the operating mode provides for a switch from the simple dehumidification mode to the parallel dehumidification mode if the upstream temperature is lower than said limit temperature, reduced by a switching variable,

[0013] - said switching variable depends on a flow rate of said passenger compartment thermoregulation fluid and / or an outside temperature,

[0014] - said step of determining the operating mode provides for taking into account one or more of the following additional parameters: o a temperature difference between the outside air flow and the air flow coming from the passenger compartment, o a temperature of the outside air flow, o a flow rate of said passenger compartment thermoregulation fluid, o a flow rate of said refrigerant fluid, o an opening rate of a refrigerant fluid expansion valve in said second branch, - said step of determining the operating mode favors the choice of the simple dehumidification mode in the case of a supply with low flow rate recirculation of said thermoregulation fluid,

[0015] - said method comprises a step of determining a supply mode making it possible to set a maximum quantity of air flow coming from the passenger compartment,

[0016] - said step of determining the supply mode takes into account said flow rate of the passenger compartment thermoregulation fluid,

[0017] - said step of determining the supply mode uses a data file comprising, for values ​​of the flow rate of the thermoregulation fluid of the passenger compartment, maximum values ​​of a flow rate of the air flow coming from the passenger compartment, possibly expressed in the form of a ratio related to the sum of the flow rates of the outside air flow and the air flow coming from the passenger compartment,

[0018] - said system alternately allows the thermoregulation fluid of the passenger compartment to be supplied using the outside air flow only, according to another supply mode, called without recirculation, and according to the supply mode with recirculation,

[0019] - said step of determining a supply mode also makes it possible to choose between supply modes with or without recirculation,

[0020] - said method comprises a step of controlling the expansion valve of said second branch in said parallel dehumidification mode,

[0021] - said control step makes it possible to vary a flow rate of said refrigerant fluid in an interval ranging from a zero value to a maximum value,

[0022] - said first branch comprises a first heat exchanger for heat exchange between the refrigerant fluid and the first heat transfer fluid,

[0023] - said second branch comprises a second heat exchanger for heat exchange between the refrigerant fluid and the second heat transfer fluid,

[0024] - said circuit comprises a first bi-fluid exchanger supplying said first and second branches, said first bi-fluid exchanger being intended for a heat exchange between said refrigerant fluid and another heat transfer fluid,

[0025] - said other fluid is the passenger compartment thermoregulation fluid,

[0026] - said other heat transfer fluid is a first heat transfer liquid,

[0027] - said system comprises a heating radiator, intended for an exchange of heat between the first heat transfer fluid and the thermoregulation fluid of the passenger compartment,

[0028] - said system comprises a first loop of the first heat transfer fluid, said first loop comprising said first bi-fluid exchanger and said heating radiator,

[0029] - said first fluid is the passenger compartment thermoregulation fluid,

[0030] - said first fluid is a second heat transfer liquid,

[0031] - said first heat exchanger forms a second bi-fluid exchanger, intended for heat exchange between the refrigerant fluid and the second heat transfer liquid,

[0032] - said system comprises a cooling radiator crossed by said second heat transfer fluid and said passenger compartment thermoregulation fluid,

[0033] - said system comprises a second loop of the second heat transfer fluid, said second loop comprising said second bi-fluid exchanger and said cooling radiator.

[0034] The invention will be better understood, and other aims, details, characteristics and advantages thereof will appear more clearly during the detailed explanatory description which follows, of at least one embodiment of the invention given by way of purely illustrative and non-limiting example, with reference to the appended schematic drawings among which:

[0035] [Fig 1] schematically illustrates an example of a refrigerant circuit used in a process according to the invention, in simple dehumidification mode [Editor's note: it will be adapted with the final drawings];

[0036] [Fig 2] schematically illustrates an example of a refrigerant circuit used in a process according to the invention, in parallel dehumidification mode [Editor's note: it will be adapted with the final drawings]; [Fig 3] schematically illustrates an embodiment of the process according to the invention.

[0037] It should first be noted that the terms upstream and downstream used in the following description refer to the direction of circulation of the fluid in question. Furthermore, the terms "first", "second", "third", etc. are only used to distinguish the components concerned from each other and do not indicate an order or a possible importance of said components.

[0038] The invention relates to a method for controlling the temperature regulation of a passenger compartment, in particular a motor vehicle. In particular, it concerns an electric or hybrid motor vehicle which comprises an electric motor which provides engine torque to the drive wheels of the vehicle. The electric motor is supplied with electric current at least by batteries, called drive batteries.

[0039] As illustrated in Figures 1 and 2, the thermoregulation of the passenger compartment operates using a thermoregulation system. Said system is configured for thermal treatment of a fluid I, called thermoregulation, forming an air flow intended to be sent to the passenger compartment. Said system comprises for this purpose here a heating, ventilation and / or air conditioning housing 2, configured to be crossed by said thermoregulation fluid. In the context of an application to a passenger compartment of a motor vehicle, said housing 2 is intended to be located, for example, under a dashboard of said vehicle.

[0040] Said system comprises a refrigerant circuit 10. The refrigerant is, for example, a hydrofluorocarbon, such as R-134a, or a fluid known as R1234yf. Alternatively, it is carbon dioxide, also known as R744.

[0041] Said circuit 10 is configured to carry out a thermodynamic loop successively comprising a compression phase, a first heat exchange phase with decrease in enthalpy, an expansion phase and a second heat exchange phase with increase in enthalpy.

[0042] Said circuit 10 comprises a first branch 12 and a second branch 14, extending in parallel, here between a first branch point 16 and a second junction point 18. Said first branch 12 is intended for heat exchange with a first heat transfer fluid. Said second branch 14 is intended for heat exchange with a second heat transfer fluid.

[0043] As will be developed further, said circuit 10 is configured to alternately supply said first branch 12 only, according to a first operating mode, called simple dehumidification, allowing dehumidification of the passenger compartment by means of the first heat transfer fluid, and said first and second branches 12, 14 simultaneously, according to a second operating mode, called parallel dehumidification, allowing, as in the first case, dehumidification of the passenger compartment by means of the first heat transfer fluid. This second operating mode also makes it possible to take calories from the second heat transfer fluid.

[0044] Said first branch 12 comprises a first heat exchanger 30 for heat exchange between the refrigerant fluid and the first heat transfer fluid.

[0045] Said refrigerant circuit here comprises a first dual-fluid exchanger 20 supplying said first and second branches 12, 14 with refrigerant. It is connected downstream, directly or indirectly, to said first branch point 16. Said first dual-fluid exchanger 20 is intended for a heat exchange between said refrigerant and another heat transfer fluid.

[0046] In the embodiment shown, said first heat transfer fluid exchanging heat with the refrigerant fluid at the first heat exchanger 30 is the thermoregulation air flow I. In other words, said first exchanger 30 is located in said housing 2. It is formed, for example, of a gas evaporator or heater.

[0047] Said other heat transfer fluid exchanging heat with said refrigerant fluid at the first bi-fluid exchanger 20 is a first heat transfer liquid. This is, for example, water possibly with added antifreeze, such as glycol.

[0048] According to this variant, said system comprises a heating radiator 21, intended for an exchange of heat between the first heat transfer fluid and the thermoregulation fluid of the passenger compartment I. For this, said system advantageously comprises a first loop of said first heat transfer fluid, not illustrated. Said first loop comprises said first bi-fluid exchanger 20 and said heating radiator 21. Said first bi-fluid exchanger is formed, for example, of a condenser or gas cooler, called water.

[0049] According to another variant, not shown, said other fluid exchanging heat with said refrigerant fluid at the level of the bi-fluid exchanger 20 is directly the thermoregulation fluid of the passenger compartment I. According to this variant, said first bi-fluid exchanger 20 is located in said housing 2. It is, for example, a condenser or gas cooler, called internal.

[0050] According to an alternative embodiment, not shown, said first fluid exchanging heat with the refrigerant fluid at the first heat exchanger 30 is a second heat transfer liquid, possibly of the same nature as the first heat transfer fluid mentioned above.

[0051] Said first heat exchanger located in the first branch 12 then forms a second bi-fluid exchanger, intended for a heat exchange between the refrigerant fluid and the second heat transfer fluid. Said system comprises a cooling radiator crossed by said second heat transfer fluid and said passenger compartment thermoregulation fluid I. Said cooling radiator is housed in the housing 2 in place of the evaporator or gas heater mentioned above. For this, said system advantageously comprises a second loop of the second heat transfer fluid. Said second loop comprises said first heat exchanger of the first branch 12 and said cooling radiator.

[0052] Referring again to Figures 1 and 2, it can be seen that said second branch 14 comprises a second heat exchanger 22 for heat exchange between the refrigerant fluid and the second heat transfer fluid. The second heat transfer fluid is formed here from an air flow, called external, E. Said second heat exchanger 22 comprises, in particular, a condenser or gas cooler. It is located, for example, on the front face, behind a grille, under a hood of the vehicle.

[0053] The refrigerant circuit 10 here comprises successively, in the direction of circulation of the refrigerant, in a main refrigerant loop, a compressor 40, the first bi-fluid exchanger 20, a refrigerant storage device 42, said bifurcation point 16, a first expansion member 44, the first heat exchanger 30 and said first junction point 18. Said circuit 10 further comprises, possibly, a heat exchanger 46, called internal, allowing an exchange of heat between said refrigerant and itself, at different pressure levels. Said internal exchanger 46 comprises, for example, a first pass 46a, intended to be crossed by the high-pressure refrigerant, and / or a second pass 46b, intended to be crossed by the low-pressure refrigerant. The first pass 46a is in the main loop downstream of the storage device 42 and upstream of the diversion point 16.The second pass 46b is in the main loop downstream of junction point 18 and upstream of compressor 40.

[0054] The first bi-fluid exchanger 20 is here connected directly to the compressor 12, i.e. without the presence of another heat exchanger between the compressor 12 and itself.

[0055] Said second branch 14 comprises, for example, starting from the first branch point 16, a second expansion member 48 and said second heat exchanger 22 before returning to said first junction point 18.

[0056] Said refrigerant circuit 10 further comprises here a third branch 50 mounted in bypass between said first bypass point 16 and said first junction point 18. Said third branch 50 comprises, for example, a third expansion member 52 and another bi-fluid exchanger 54.

[0057] Said other bi-fluid exchanger 54 is configured to allow heat exchange between the refrigerant fluid and another fluid, for example intended for direct or indirect cooling of an electrical energy storage device and / or an electric vehicle motor. This type of heat exchanger is commonly called a “cooler” by those skilled in the art.

[0058] The expansion members 44, 48, 52 comprise, for example, an electronic expansion valve, or electronic “expansion valve”.

[0059] Said system is configured for supplying the thermoregulation fluid to the passenger compartment using a mixture of an outside air flow 11 and an air flow from the passenger compartment I2, according to a supply mode, called with recirculation. Such a recirculation mode makes it possible to benefit from the thermal inertia of the air present in the passenger compartment to limit the energy to be supplied to the thermoregulation system. Said system is configured so that a mixture of the outside air flow 11 and the air flow from the passenger compartment I2 takes place, for example, in said housing 2, upstream of the first heat exchanger 12 according to the direction of circulation of said thermoregulation air flow I. The proportion of each of the flows 11 and I2 determines an air inlet temperature in said first exchanger 30, or, where appropriate, said cooling exchanger, depending on an outside temperature and a passenger compartment temperature.

[0060] Said system is further configured to alternately allow a supply of the thermoregulation fluid of the passenger compartment I using the outside air flow 11 only, according to another supply mode, called without recirculation, and according to the supply mode with recirculation.

[0061] Figure 1 illustrates the operation of the refrigerant circuit in simple dehumidification mode. In such a case, the refrigerant takes calories from said thermoregulation air flow I, using the first heat exchanger 30, and transfers them, using said first bi-fluid exchanger 20, to said other heat transfer fluid, via said refrigerant loop 10. It is thus possible to dry said thermoregulation air flow I by cooling it. In addition, if necessary, the calories supplied to the other heat transfer fluid make it possible to heat said thermoregulation air flow I, after having dried it, this via said first heat transfer liquid loop mentioned above.

[0062] In this mode of operation, starting from the compressor 40, the refrigerant fluid follows the main loop by passing into the first bi-fluid exchanger 20 which operates as a condenser or gas cooler by exchanging heat with the other heat transfer fluid in order to dissipate the calories of the refrigerant fluid in said other heat transfer fluid. It then passes through the storage device 42 and the high pressure pass 46a of the internal exchanger 46. At the first branch point 16, said refrigerant fluid exclusively uses the first branch 12, the second expansion member 48 being closed.

[0063] Said third expansion member 52 also being closed, the refrigerant fluid continues downstream towards the first expansion member 44, provided to be active. It thus undergoes expansion then passes through the first heat exchanger 30, operating as an evaporator and / or gas heater. As mentioned above, said refrigerant fluid thus dries the thermoregulation air flow I by cooling it. The refrigerant fluid then returns to the compressor 12 via the first junction point 18 and the low pressure pass 46b of the internal exchanger 46. Figure 2 illustrates the operation of the refrigerant fluid circuit in parallel dehumidification mode.In such a case, on the one hand, as in the operating mode in simple dehumidification mode, the refrigerant fluid takes calories from said thermoregulation air flow I, using the first heat exchanger 30, and transfers them, using said first bi-fluid exchanger 20, to said other heat transfer fluid, via said refrigerant fluid loop 10. On the other hand, the refrigerant fluid takes calories from external air flow E to transfer them to the refrigerant fluid via the second exchanger 22. It is thus possible to continue to dry said thermoregulation air flow I by cooling it. The calories provided by said external fluid E also make it possible, in particular, to be able to heat said thermoregulation air flow I even more, after having dried it, via said first heat transfer liquid loop.

[0064] In this mode of operation, starting from the compressor 20, the refrigerant passes into the first dual-fluid exchanger 20 which operates as a condenser or gas cooler by exchanging heat with the other heat transfer fluid in order to dissipate the calories of the refrigerant in said other heat transfer fluid. It then passes through the storage device 42 and the high-pressure pass 46a of the internal exchanger 46. At the first branch point 16, said refrigerant then separates into two fractions to pass through both the first branch 12 and the second branch 14.

[0065] As already stated, along the first branch 12, the refrigerant passes through the first expansion member 44, provided to be active. It thus undergoes expansion and then passes through the first heat exchanger 30, operating as an evaporator and / or gas heater. As mentioned above, said refrigerant thus dries the thermoregulation air flow I by cooling it. Along the second branch 14, the refrigerant passes through the second expansion member 48, provided to be active, and the second heat exchanger 22, operating as an evaporator and / or gas heater. As mentioned above, said refrigerant thus captures calories from said external air flow E.

[0066] Results of a test are given in the table below in which it is indicated whether or not a given operating mode allows satisfactory demisting under certain conditions of temperature Tu, called upstream, of said thermoregulation fluid I before passing into the evaporator 30, and of flow rate Q of said passenger compartment thermoregulation fluid I. Said temperatures Tu are indicated in rows, in degrees Celsius. Said flow rates Q are indicated in columns, in kilograms per hour.

[0067] Said temperature Tu recorded before passing through the evaporator 30 corresponds to an air recycling rate indicated in parentheses next to the value of said temperature T. Said air recycling rate is defined by the flow rate of the air flow I2 coming from the passenger compartment over the total flow rate of the passenger compartment thermoregulation fluid generated by the air flow 11 coming from outside and said air flow I2 coming from the passenger compartment. In other words, for example, for a rate of 40% (corresponding to the temperature value Tu of 22°C), the passenger compartment thermoregulation air flow is generated by a mixture composed of 40% of an air flow coming from the passenger compartment and 60% of an air flow coming from outside. For this test, the outside air temperature is 0°C. The flow rate of the external air flow E and the compression level provided by the compressor 40 are fixed.

[0068] The mention “DS” in a cell means that simple dehumidification allows good demisting under the temperature conditions Tu and flow rate Q of the corresponding cell.

[0069] The mention “DP” in a cell means that parallel dehumidification allows good demisting under the temperature Tu and flow rate Q conditions of the corresponding cell.

[0070] The cell indicating the DS / DP mention corresponds to a borderline case between simple dehumidification mode and parallel dehumidification.

[0071] The mention “X” in a cell means that neither the simple dehumidification mode nor the parallel dehumidification mode allows satisfactory demisting under the temperature T and flow rate Q conditions of the corresponding cell. This table shows that air recycling is possible in passenger compartment dehumidification mode and that the use of different dehumidification modes makes it possible to extend the operating range where such a combination is relevant. The total flow rate of the thermoregulation airflow and / or the recycling rate influence the operating mode to be chosen. As long as the airflow rates Q remain relatively low, a simple dehumidification mode can be used while it becomes necessary to switch to a parallel dehumidification mode above a certain airflow rate Q, for a given upstream temperature Tu. Similarly, as long as the recycling rate remains relatively low, a simple dehumidification mode can be used while it becomes necessary to switch to a parallel dehumidification mode above a certain recirculation rate, for a given flow rate Q.

[0072] We also note that the lower the outside temperature and / or the higher the heating setpoint, which will result in a given upstream temperature Tu due to air recycling, the more necessary it is to use the parallel dehumidification mode, for a given flow rate Q.

[0073] Furthermore, above certain values, neither mode is compatible with air recirculation.

[0074] As illustrated in Figure 3, according to the invention, said method for controlling the thermoregulation of said passenger compartment thermoregulation air flow takes advantage of the observation made above. It thus comprises a step of determining an operating mode from among the simple 100 and parallel 102 dehumidification modes so that the determined operating mode occurs, at least in supply mode with recirculation, taking into account usage conditions.

[0075] Preferably, said method comprises a step of determining the upstream temperature Tu, originating from the mixture of the outside air flow 11 and the air flow I2 originating from the passenger compartment, that is to say, here, as already mentioned above, the temperature of the thermoregulation air flow I upstream of the first heat exchanger 30.

[0076] Said step of determining the operating mode provides for a transition 104 from the parallel dehumidification mode 102 to the simple dehumidification mode 100 if the upstream temperature is higher than a limit temperature Tl. Conversely, said step of determining the operating mode provides for a transition 106 from the simple dehumidification mode 100 to the parallel dehumidification mode 102 if the upstream temperature is lower than said limit temperature Tl but this time, reduced by a switching variable Tb. For reasons of homogeneity, said switching variable Tb is also a temperature.

[0077] In other words, according to this implementation mode, the transition from one operating mode to the other is not done for the same temperature value if the system is in simple dehumidification mode or in parallel dehumidification mode at the previous instant. In other words, the transition from one operating mode to the other takes into account a state of the system at the previous instant. Such a shift makes it possible to benefit from the better energy efficiency of the simple dehumidification mode over a wider operating range.

[0078] Advantageously, said switching variable depends on the flow rate of said passenger compartment thermoregulation fluid I and / or said outside temperature. For temperatures Tu and Tl expressed in °C, said switching variable Tb is, for example, between 0 and 5°C.

[0079] Preferably, said step of determining the operating mode further comprises taking into account one or more of the following parameters:

[0080] - a temperature difference between the outside air flow and the air flow coming from the passenger compartment,

[0081] - an outside air flow temperature,

[0082] - a flow rate of said passenger compartment thermoregulation fluid,

[0083] - a flow rate of said refrigerant,

[0084] - an opening rate of a refrigerant fluid expansion valve in said second branch.

[0085] It can be seen that the invention makes it possible, by using all or part of the information mentioned above, to carry out a check without having to use information on a humidity level in the passenger compartment.

[0086] Preferably, said method further comprises a step of determining a supply mode between the supply modes with or without recirculation. Said step of determining the supply mode leads to the choice of the mode without recirculation, for example, when neither the simple dehumidification mode nor the parallel dehumidification mode can operate with a proportion of air coming from the passenger compartment without too high a risk of generating mist and / or without being able to reach the desired temperature setpoint.

[0087] Said step of determining the supply mode takes into account said flow rate of the passenger compartment thermoregulation fluid I. Advantageously, said determination step uses a data file comprising, for values ​​of the flow rate Q of the passenger compartment thermoregulation fluid, maximum values ​​of a flow rate of the air flow I2 coming from the passenger compartment, possibly expressed in the form of a ratio related to the sum of the flow rates of the outside air flow 11 and the air flow coming from the passenger compartment I2, namely the recycling rate already mentioned above.

[0088] The file is presented, for example, in the form of a data table. An example is given below:

[0089] In this table, the left column indicates the value of said flow rate Q, in kilograms per hour, and the right column indicates the maximum value of the air recycling ratio corresponding to said flow rate Q. For example, for a flow rate Q of 150 kg / h, the recycling rate must not exceed 40%.

[0090] Preferably, said step of determining the operating mode favors the choice of the simple dehumidification mode in the case of supply with low flow rate recirculation of said thermoregulation fluid. This means, for example, a flow rate of less than 250 kg / h.

[0091] Said method advantageously comprises a step of controlling an expansion valve of said second branch 14 at least in said parallel dehumidification mode. Said control step makes it possible, for example, to vary a flow rate of said refrigerant fluid in an interval ranging from a zero value to a maximum value. A zero flow rate corresponds to a configuration of absence of circulation of the refrigerant fluid in said second branch 14 such as that encountered, in particular, in the operating mode in simple dehumidification mode. A strictly positive flow rate corresponds, up to a certain value, to an operating mode with expansion of the refrigerant fluid, such as that encountered, in particular, in the operating mode in parallel dehumidification mode.

[0092] A maximum flow rate corresponds to another operating mode in which the refrigerant circulates in said second branch 14, without expansion. This may be, for example, a passenger compartment air conditioning mode.

Claims

CLAIMS 1. Method for controlling thermoregulation of a passenger compartment, in particular of a motor vehicle, using a thermoregulation system, said system comprising a refrigerant circuit (10), said circuit (10) being configured to perform a thermodynamic cycle, said circuit (10) comprising a first branch (12) and a second branch (14), extending in parallel, said first branch (12) being intended for heat exchange with a first heat transfer fluid, said second branch (14) being intended for heat exchange with a second heat transfer fluid, said circuit being configured to alternately supply said first branch (12) only, according to a first operating mode, called simple dehumidification (100), allowing dehumidification of the passenger compartment by means of the first heat transfer fluid, and said first and second branches (12, 14) simultaneously, according to a second operating mode,said parallel dehumidification (102), making it possible to dehumidify the passenger compartment via the first heat transfer fluid and to take calories from the second heat transfer fluid, said system being configured for a supply of a thermoregulation fluid to the passenger compartment using a mixture of an outside air flow and an air flow coming from the passenger compartment, according to a supply mode, said with recirculation, said method comprising a step of determining an operating mode from among the simple and parallel dehumidification modes so that the determined operating mode occurs, under certain conditions, at least in supply mode with recirculation., 2. Method according to claim 1 wherein said step of determining the operating mode provides for a switch (104) from the parallel dehumidification mode (102) to the simple dehumidification mode (100) if a temperature (Tu), called upstream, of the mixture of the outside air flow and the air flow coming from the passenger compartment is higher than a limit temperature (Tl).

3. Method according to any one of the preceding claims in which said step of determining the operating mode provides for a transition (106) from the simple dehumidification mode (100) to the dehumidification mode parallel if the upstream temperature (Tu) is lower than said limit (Tl), reduced by a switching variable (Tb).

4. Method according to the preceding claim in which said switching variable (Ts) depends on the flow rate of said passenger compartment thermoregulation fluid and / or said outside temperature.

5. Method according to any one of the preceding claims in which said step of determining the operating mode provides for taking into account one or more of the following additional parameters: - a temperature difference between the outside air flow and the air flow coming from the passenger compartment, - an outside air flow temperature, - a flow rate of said passenger compartment thermoregulation fluid, - a flow rate of said refrigerant, - an opening rate of a refrigerant fluid expansion valve in said second branch.

6. Method according to any one of the preceding claims in which said step of determining the operating mode favors the choice of the simple dehumidification mode (100) in the case of supply with low flow rate recirculation of said thermoregulation fluid.

7. Method according to any one of the preceding claims, in which said method comprises a step of determining a supply mode making it possible to set a maximum quantity of air flow coming from the passenger compartment.

8. Method according to the preceding claim in which said step of determining the supply mode takes into account said flow rate of the passenger compartment thermoregulation fluid.

9. Method according to the preceding claim in which said determination step uses a data file comprising, for flow rate values of passenger compartment thermoregulation fluid, maximum values of a flow rate of the air flow coming from the passenger compartment, possibly expressed in the form of a ratio to the sum of the flow rates of the outside air flow and the air flow coming from the passenger compartment, 10. Method according to any one of claims 7 to 9, said system (10) alternately allowing a supply of the thermoregulation fluid of the passenger compartment using the outside air flow only, according to another supply mode, called without recirculation, and according to the supply mode with recirculation, said step of determining the supply mode also allows a choice between the supply modes with or without recirculation.

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