Thermal conditioning system

Abstract

The invention relates to a method (2) for controlling a thermal conditioning system (100) of a vehicle, the system comprising a coolant (FR) circuit (1), the coolant circuit (1) comprising: - a main loop (A), this main loop (A) comprising, in sequence: -- a compression device (3), -- a first heat exchanger (4) arranged for a flow of a heat-transfer fluid (Ffc) to pass through same, -- a second heat exchanger (5) arranged for an air flow (Fe) external to the vehicle to pass through same, -- a first expansion member (6); and - a secondary branch (B), comprising, in sequence, a second expansion member (8) and a two-fluid heat exchanger (7) arranged in a heat-transfer liquid (LC) circuit (200), the heat-transfer liquid (LC) circuit (200) comprising an electric heating device (9) for heating the heat-transfer liquid (LC), the thermal conditioning system (100) being configured to operate in an "electric heating" mode, in a "heat pump" mode or in an "electric heating and heat pump" mode, the method comprising a condition for switching from the "electric heating" mode to the "electric heating and heat pump" mode, the method executing the switch from the "electric heating" mode to the "electric heating and heat pump" mode when this condition for switching is met.

Description

Description Title: THERMAL CONDITIONING SYSTEM Technical field [1] The present invention relates to the field of thermal conditioning systems. Such systems can, for example, be fitted to motor vehicles. These systems make it possible to ensure thermal regulation of various components, such as, for example, the passenger compartment or an electrical energy storage battery, when the vehicle is electrically powered. Heat exchanges are managed mainly by the compression and expansion of a refrigerant circulating in a circuit in which several heat exchangers are arranged. A compressor makes it possible to pass the refrigerant at high pressure and circulate it in the circuit. Prior art [2] The refrigerant circuit usually comprises a main loop and several bypass branches which allow multiple combinations of refrigerant circulation to be achieved. Many operating modes can thus be obtained, for example cooling the air in the passenger compartment, heating the air in the passenger compartment, dehumidifying the air in the passenger compartment, or cooling the vehicle batteries. It is known to use an additional heating device to supplement the heat supplied by the refrigerant circuit in certain heating modes. [3] Methods are also known for minimizing the consumption of the compressor and the additional heating device within the different operating modes. Methods are also known for choosing the mode best suited to the need. [4] A disadvantage is that the criteria for choosing a mode or switching from one operating mode to another are not optimized to ensure that the selected mode is the mode that guarantees achieving the targeted performance with the minimum consumption. Summary [5] To this end, one aspect of the present invention provides a method for controlling a thermal conditioning system of a vehicle, said system comprising a refrigerant circuit, said refrigerant circuit comprising: a main loop, said main loop successively comprising, according to the direction of circulation of the refrigerant: -- a device for compressing the refrigerant fluid, -- a first heat exchanger arranged to be crossed by a flow of a heat transfer fluid and intended to heat said heat transfer fluid, -- a second heat exchanger located between the first heat exchanger and the compression device, arranged to be crossed by a flow of air from outside the vehicle and intended in particular to evaporate the refrigerant fluid, -- a first expansion member located between the first heat exchanger and the second heat exchanger, - a first secondary branch, connecting a branch point to a junction point, said first secondary branch successively comprising, according to the direction of circulation of the refrigerant fluid, a second expansion member, a two-fluid heat exchanger arranged in a heat transfer fluid circuit and intended to evaporate the refrigerant fluid, said branch point being located between the first heat exchanger and the first expansion member, said junction point being located between the second heat exchanger and the compression device, said heat transfer fluid circuit comprising an electric heating device for heating said heat transfer fluid, said thermal conditioning system being configured to operate in an “electric heating” mode, in a “heat pump” mode or in an “electric heating and heat pump” mode: - said “electric heating” mode being a mode in which the electric heating device is active and serves as a heat source for heating the heat transfer fluid and evaporating the refrigerant in the dual-fluid heat exchanger, the heat being returned by the first heat exchanger to the heat transfer fluid passing through it, thanks to the compression of the refrigerant within the compression device, the second heat exchanger being inactive, said “heat pump” mode being a mode where the outside air serves as a heat source for evaporating the refrigerant in the second heat exchanger, said heat taken by the second heat exchanger being returned by the first heat exchanger to the heat transfer fluid passing through it, thanks to the compression of the refrigerant within the compression device, the dual-fluid heat exchanger being inactive, - said “electric heating and heat pump” mode being a mode in which on the one hand the electric heating device is active and serves as a heat source for heating the heat transfer fluid and evaporating the refrigerant in the dual-fluid heat exchanger, and in which on the other hand the outside air serves as a heat source for evaporating the refrigerant in the second heat exchanger, all of the heat taken by the dual-fluid heat exchanger and by the second heat exchanger being restored by the first heat exchanger to the heat transfer fluid passing through it, thanks to the compression of the refrigerant within the compression device, said method comprising: - a step of determining a value of a quantity representative of the evaporation temperature of the refrigerant in the second heat exchanger, - a step of determining an exterior temperature of the vehicle Text, - a comparison step between the value of the quantity representative of the evaporation temperature of the refrigerant in the second exchanger of heat and a first threshold value of the quantity representative of the evaporation temperature depending on the outside temperature, - a condition for switching from the “electric heating” mode to the “electric heating and heat pump” mode, said switching condition being that the value of the quantity representative of the evaporation temperature of the refrigerant in the second heat exchanger crosses the first threshold value of the quantity representative of the evaporation temperature in a first direction, the method executing the switch from the “electric heating” mode to the “electric heating and heat pump” mode when said condition for switching from the “electric heating” mode to the “electric heating and heat pump” mode is fulfilled. [6] Thus this aspect of the invention makes it possible to switch from the “electric heating” mode to the “electric heating and heat pump” mode when it turns out that the “electric heating and heat pump” mode is capable of ensuring the required heating performance, while consuming less than the “electric heating” mode. [7] According to particular embodiments, the method may comprise one or more of the following characteristics, taken in isolation or in all technically possible combinations: - the condition for switching from “electric heating” mode to “electric heating and heat pump” mode is a necessary and sufficient condition for switching from “electric heating” mode to “electric heating and heat pump” mode; - the quantity representative of the evaporation temperature in the second heat exchanger is an evaporation temperature of the refrigerant fluid in the second exchanger; - the quantity representative of the evaporation temperature in the second heat exchanger is a temperature of the refrigerant fluid at the outlet of the second heat exchanger; - the quantity representative of the evaporation temperature in the second heat exchanger is a temperature of the refrigerant fluid at the inlet of the second heat exchanger; - the quantity representative of the evaporation temperature in the second heat exchanger is an interpolation temperature between the temperature of the refrigerant fluid at the inlet of the second heat exchanger and the temperature of the refrigerant fluid at the outlet of the second heat exchanger; - the quantity representative of the evaporation temperature in the second heat exchanger is an evaporation pressure of the refrigerant fluid in the second heat exchanger; - the quantity representative of the evaporation temperature in the second heat exchanger is a pressure of the refrigerant fluid at the inlet of the second heat exchanger; - the quantity representative of the evaporation temperature in the second heat exchanger is a pressure of the refrigerant fluid at the outlet of the second heat exchanger; - the quantity representative of the evaporation temperature in the second heat exchanger is an interpolation pressure between the pressure of the refrigerant fluid at the inlet of the second heat exchanger and the pressure of the refrigerant fluid at the outlet of the second heat exchanger; - said refrigerant circuit comprises a refrigerant reserve device in the main loop located between the first heat exchanger and the compression device; - said refrigerant reserve device is a gas / liquid separation bottle located on the main loop between the first heat exchanger and the first expansion member; - said refrigerant reserve device is a gas / liquid separation accumulator located on the main loop between the second heat exchanger and the compression device; - the first trigger organ has a variable opening section; - the second trigger organ has a variable opening section; - the refrigerant circuit comprises a non-return valve in the main loop located between the outlet of the second heat exchanger and the first junction point; - the method comprises a step of determining a temperature outside the vehicle; - the circuit comprises a temperature sensor for measuring the temperature outside the vehicle, an output signal of said sensor is the value of said temperature outside the vehicle; - the circuit comprises a pressure sensor for measuring the pressure of the refrigerant fluid at the outlet of the second heat exchanger, an output signal of said pressure sensor being a value of said pressure at the outlet of the second heat exchanger; - the circuit comprises a pressure sensor for measuring the pressure of the refrigerant fluid at the inlet of the second heat exchanger, an output signal of said pressure sensor being a value of said pressure at the inlet of the second heat exchanger; - the circuit comprises a pressure sensor for measuring the pressure of the refrigerant in the second heat exchanger, an output signal of said pressure sensor being a value of said pressure in the second heat exchanger; - the circuit comprises a temperature sensor for measuring the temperature of the refrigerant in the second heat exchanger, an output signal of said temperature sensor being a value of said temperature of the refrigerant at the outlet of the second heat exchanger; - the circuit comprises a pressure sensor for measuring the pressure of the refrigerant fluid at the inlet of the compression device, an output signal of said pressure sensor being a value of said pressure at the inlet of the compression device; - the method comprises calculating a pressure drop of the refrigerant fluid between the second heat exchanger and the inlet of the compression device depending on the flow rate of refrigerant fluid circulating between the outlet of the second heat exchanger and the inlet of the compression device; - the flow rate of refrigerant circulating between the outlet of the second heat exchanger and the inlet of the compression device is estimated from the speed of the compression device and the pressure at the inlet of the compression device; - the circuit comprises a temperature sensor for measuring the temperature of the refrigerant fluid at the inlet of the compression device, an output signal of said temperature sensor being a value of said temperature at the inlet of the compression device; - the flow rate of refrigerant circulating between the outlet of the second heat exchanger and the inlet of the compression device is estimated from the speed of the compression device, the pressure at the inlet of the compression device, and the temperature at the inlet of the compression device; - the pressure at the outlet of the second heat exchanger is calculated from the pressure at the inlet of the compression device and the value of the pressure drop of the refrigerant fluid between the outlet of the second heat exchanger and the inlet of the compression device; - the first threshold value of the quantity representative of the evaporation temperature dependent on the outside temperature is a first threshold pressure value equal to the saturation pressure of the refrigerant fluid at the outside temperature minus k, with k which is a constant between 0.15 bar and 0.25 bar and preferably equal to 0.2 bar; - the condition for switching from “electric heating” mode to “electric heating and heat pump” mode is that the value of the pressure of the refrigerant fluid at the outlet of the second heat exchanger is lower than the value of the first threshold pressure; - the condition for switching from the “electric heating” mode to the “electric heating and heat pump” mode is that the value of the evaporation pressure of the refrigerant in the second heat exchanger of the refrigerant in the second heat exchanger is lower than the value of the first threshold pressure; - the first threshold value of the quantity representative of the evaporation temperature dependent on the outside temperature is a first threshold temperature value equal to the outside temperature minus x, with x being a constant between 1.5°C and 2.5°C bar and preferably equal to 2°C; - the condition for switching from “electric heating” mode to “electric heating and heat pump” mode is that the value of the evaporation temperature of the refrigerant in the second heat exchanger is lower than the value of the first threshold temperature; - the method comprises a condition for switching from the “electric heating and heat pump” mode to the “electric heating” mode, said switching condition being that the quantity representative of the evaporation temperature of the refrigerant fluid in the second heat exchanger crosses a second threshold value in a second direction, opposite to the first direction; - the second threshold value is a second threshold pressure value equal to the saturation pressure of the refrigerant fluid at the temperature outside the vehicle plus k' with k' which is a constant between 0.05 bar and 0.2 bar and preferably equal to 0.1 bar, - the condition for switching from “electric heating” mode to “electric heating and heat pump” mode is that the pressure of the refrigerant in the second heat exchanger is higher than the second threshold pressure value; - the condition for switching from “electric heating and heat pump” mode to “electric heating” mode is that the pressure of the refrigerant fluid at the outlet of the second heat exchanger is greater than the second threshold pressure value; - the condition for switching from “electric heating and heat pump” mode to “electric heating” mode is that the evaporation pressure of the refrigerant in the second heat exchanger is higher than the second threshold pressure value; - the second threshold value is a second threshold temperature value equal to the temperature outside the vehicle plus x' with x' which is a constant between 0.5°C and 2°C and preferably equal to 1°C; - the condition for switching from “electric heating” mode to “electric heating and heat pump” mode is that the temperature of the refrigerant in the second heat exchanger is higher than the second threshold temperature value; - the method executes the transition from the “electric heating and heat pump” mode to the “electric heating” mode when the condition for transitioning from the “electric heating and heat pump” mode to the “electric heating” mode is met; - the condition for switching from “electric heating and heat pump” mode to “electric heating” mode is necessary and sufficient for switching from “electric heating and heat pump” mode to “electric heating” mode; - the circuit comprises a temperature sensor of the heat transfer fluid passing through the first heat exchanger, the sensor being downstream of said first heat exchanger, an output signal of said temperature sensor being a value of said heat transfer fluid temperature downstream of the first heat exchanger; - the method comprises a step of determining a temperature of heat transfer fluid passing through the first heat exchanger, downstream of said first heat exchanger; the method comprises a step of comparing the temperature of the heat transfer fluid downstream of the first heat exchanger and a heating setpoint temperature value; - the method comprises a condition for switching from the “electric heating and heat pump” mode to the “heat pump” mode, said switching condition being that the value of the heat transfer fluid temperature downstream of the first heat exchanger is greater than the heating setpoint temperature + a, with a being a constant having a value between 0.5°C and 2°C, and preferably equal to 1°C; - The method executes the transition from the “electric heating and heat pump” mode to the “heat pump” mode when the condition for transitioning from the “electric heating and heat pump” mode to the “heat pump” mode is met; - the condition for switching from “electric heating and heat pump” mode to “heat pump” mode is a necessary and sufficient condition for switching from “electric heating and heat pump” mode to “heat pump” mode; - the method comprises a step of comparing the speed of the compression device and a maximum speed threshold value; - the method comprises a step of comparing the pressure of the refrigerant fluid at the inlet of the compression device with a minimum pressure threshold value at the inlet of the compression device; - the method comprises a first condition for switching from the “heat pump” mode to the “electric heating and heat pump” mode, said first switching condition being that the temperature of the heat transfer fluid downstream of the first heat exchanger is lower than the heating setpoint temperature - [3, with [3 which is a constant having a value between 0.5°C and 2°C, and preferably equal to 1°C; - the method comprises a second condition for switching from the “heat pump” mode to the “electric heating and heat pump” mode, said second condition for passage being that the speed of the compression device is equal to the maximum speed threshold value or that the pressure at the inlet of the compression device is equal to or less than the minimum pressure threshold value at the inlet of the compression device; - The method executes the transition from the “heat pump” mode to the “electric heating and heat pump” mode when at least the first condition for transitioning from the “heat pump” mode to the “electric heating and heat pump” mode and the second condition for transitioning from the “heat pump” mode to the “electric heating and heat pump” mode are met; - the first and second conditions for switching from “heat pump” mode to “electric heating and heat pump” mode are necessary conditions for switching from “heat pump” mode to “electric heating and heat pump” mode; - the method comprises at least one mapping of the choice of a mode from among the “electric heating”, “electric heating and heat pump” and “heat pump” modes, depending for example on the set heating power and the outside temperature; - the method comprises a step of estimating the flow rate of heat transfer fluid passing through the first heat exchanger; - the method comprises a step of determining the set heating power from a heating set temperature value, from a value of the heat transfer fluid temperature upstream of the first heat exchanger according to the direction of circulation of the heat transfer fluid flow, and from the estimation of the heat transfer fluid flow rate passing through the first heat exchanger; - in at least a first outside temperature interval, the heating mode is chosen according to said at least one map, this choice is not modified as long as the outside temperature remains in said first outside temperature interval, and in at least a second outside temperature interval, the initial heating mode is chosen according to said at least one map, then according to said conditions of passage from one heating mode to another; - in said at least second outside temperature interval, a change in the outside temperature and / or the set heating power causes a change of mode according to said mapping. [8] The invention also relates to a computer program comprising instructions which cause the thermal conditioning system to carry out the method. [9] The invention also relates to a central control unit, said unit comprising at least one computer, a memory and the computer program stored in the memory. Brief description of the drawings

[0010] Other characteristics, details and advantages of the invention will emerge more clearly on reading the description given below for purely illustrative purposes in relation to the appended drawings in which:

[0011] [Fig. 1] is a schematic view of a thermal conditioning system according to a first embodiment of the invention,

[0012] [Fig. 2] is a schematic view of said thermal conditioning system operating in a “heat pump” mode,

[0013] [Fig. 3] is a schematic view of said thermal conditioning system operating in an “electric heating and heat pump” mode,

[0014] [Fig. 4] is a schematic view of said thermal conditioning system operating in an “electric heating” mode,

[0015] [Fig. 5] is a schematic view of a mode of operation choice map,

[0016] [Fig. 6] is a flowchart describing an implementation of the method according to one aspect of the invention. Description of the embodiments

[0017] In Figures 1 to 4, lines represent the conduits connecting one element of the circuit to another element of the circuit. In Figures 2 to 4, solid, thick lines represent the conduits in which fluid or liquid circulates. Dotted lines represent conduits in which there is no circulation of fluid or liquid. Chevrons represent the direction of circulation in the conduits.

[0018] It should first be noted that the figures set out the invention in detail for its implementation, said figures being able of course to serve to better define the invention, where appropriate.

[0019] The terms upstream and downstream used in the following description refer to the direction of circulation of the fluid considered.

[0020] The terms input and output used in the following description refer to the direction of circulation of the fluid considered.

[0021] In order to differentiate the components, the terms "first", "second", etc. are used. These terms are not intended to hierarchize the components or to order them. These terms are used for the purpose of distinction and may be interchanged without impairing the implementation of the invention. For example, the term "second" does not necessarily imply the presence of two elements.

[0022] A branch is a portion of a circuit connecting one point of the circuit to another point of the circuit.

[0023] When it is specified that a branch contains a given element, this does not exclude the presence of other elements in this branch.

[0024] A conduit is a portion of a circuit connecting one point of the circuit to another point of the circuit, with no element between these two points.

[0025] The term “exchanger” is equivalent to the term “heat exchanger”, and the two terms may be used interchangeably in the following description.

[0026] An "inactive" heat exchanger is a heat exchanger in which there is no forced heat exchange.

[0027] Figure 1 illustrates an example of a thermal conditioning system 100 according to the invention comprising a refrigerant fluid circuit 1 FR and a central control unit UC comprising at least one computer, a memory and a computer program stored in the memory and configured to implement a method 2.

[0028] The central control unit UC receives information from various sensors measuring in particular the characteristics of the refrigerant fluid at various points in the circuit, and measuring in particular the characteristics of the air, heat transfer fluid and heat transfer fluid flows at various points in the thermal conditioning system 100. The electronic control unit UC also receives instructions issued by the occupants of the vehicle, such as for example the desired temperature inside the passenger compartment. The electronic control unit UC can also receive instructions from other electronic subsystems, such as for example the electrical energy storage battery management system. The central control unit UC implements control laws allowing the various actuators to be controlled, in order to ensure the control of the thermal conditioning system 100 so as to ensure the instructions received.

[0029] The refrigerant circuit 1 forms a closed circuit in which the refrigerant FR can circulate. The refrigerant circuit 1 is leak-proof when it is in a nominal operating state, i.e. without faults or leaks. Each branch and / or junction point of the circuit 1 allows the refrigerant to pass into one or other of the circuit sections joining at this connection point. The refrigerant is distributed between the circuit sections joining at a connection point by adjusting the opening or closing of the stop valves, non-return valves or expansion devices located on each of the branches of the circuit. In other words, each branch and junction point is a means of redirecting the refrigerant.Various shut-off valves and non-return valves thus make it possible to selectively direct the refrigerant fluid into the different branches of the refrigerant circuit, in order to ensure different operating modes, as will be described later.

[0030] The refrigerant FR used by refrigerant circuit 1 is a chemical fluid such as R1234yf. Other refrigerants can also be used instead, such as R134a or R290.

[0031] The thermal conditioning system 100 comprises a flow Ffc of a heat transfer fluid FC passing through a first heat exchanger of the refrigerant circuit 1. This heat transfer fluid FC may be, for example, air or heat transfer liquid.

[0032] Interior air flow Fi is understood to mean an air flow to the passenger compartment of the motor vehicle. This interior air flow Fi can circulate in a heating, ventilation and / or air conditioning installation, frequently referred to by the English term "HVAC", for "Heating, Ventilating and Air Conditioning". This installation has not been shown in the various figures. A first motor-fan unit, not shown, is arranged in the heating, ventilation and / or air conditioning installation in order to increase the flow rate of the interior air flow Fi as needed.

[0033] Outside air flow Fe is understood to mean an air flow that is not intended for the passenger compartment of the vehicle. In other words, this air flow Fe remains outside the passenger compartment of the vehicle. A second motor-fan unit, also not shown, can be activated in order to increase the flow rate of the outside air flow Fe if necessary. The flow rate provided by the first motor-fan unit as well as by the second motor-fan unit can be adjusted in real time according to the heat exchange requirements, for example by the central control unit UC of the thermal conditioning system 100.

[0034] The thermal conditioning system circuit 1 is capable of operating, for example, in several modes allowing the heating of a vehicle interior.

[0035] Refrigerant circuit 1 includes: - a main loop A, said main loop A successively comprising, according to the direction of circulation of the refrigerant fluid: -- a compression device 3 of the refrigerant fluid FR, -- a first heat exchanger 4 arranged to be crossed by a flow Ffc of a heat transfer fluid FC and intended to heat said heat transfer fluid FC, -- a second heat exchanger 5 located between the first heat exchanger 4 and the compression device 3, arranged to be crossed by a flow of air from outside the vehicle Fe and intended in particular to evaporate the refrigerant fluid FR, -- a first expansion member 6 located between the first heat exchanger 4 and the second heat exchanger 5, - a first secondary branch B, connecting a first branch point d1 to a first junction point j1, said first secondary branch B successively comprising, according to the direction of circulation of the refrigerant fluid, a second expansion member 8 and a two-fluid heat exchanger 7 arranged in a circuit 200 of heat transfer liquid LC and intended to evaporate the refrigerant fluid FR, said first branch point d1 being located between the first heat exchanger 4 and the first expansion member 6, said first junction point j1 being located between the second heat exchanger 5 and the compression device 3. Said LC heat transfer liquid circuit 200 comprises an electric heating device 9 for heating said LC heat transfer liquid and one or more elements of the drive chain, such as a battery and / or an electric motor.

[0036] In this exemplary embodiment of the invention, the flow of heat transfer fluid Ffc is an interior air flow Fi intended to be heated by passing through the first heat exchanger 4 which is then an internal condenser arranged in the housing of a ventilation, heating and / or air conditioning (“HVAC”) installation (not shown) of which it forms part.

[0037] In an exemplary embodiment not shown of the thermal conditioning system 100, the heat transfer fluid FC is a secondary heat transfer liquid intended to be heated by passing through the first heat exchanger 4, which is then a two-fluid condenser located in the under-hood environment of the vehicle.

[0038] In this example of refrigerant circuit 1 illustrated in figure 1, said refrigerant circuit 1 further comprises a refrigerant accumulation device 10 located on the main loop A between the outlet of the first heat exchanger 4 and the inlet of the first expansion member 6. Said accumulation device 10 comprises a liquid refrigerant storage volume configured to compensate for variations in the quantity of refrigerant circulating in the refrigerant circuit 1 depending on the operating conditions. Said accumulation device 10 is here a gas / liquid separation bottle 10'. Said bottle 10' can receive at its inlet a two-phase mixture of refrigerant fluid. In steady state, the refrigerant fluid FR reaching the inlet of the bottle is in the two-phase state and the refrigerant fluid FR leaving the outlet of the bottle is in the saturated liquid state.

[0039] According to an exemplary embodiment of the circuit 1 not shown, the refrigerant fluid accumulation device 10 is a gas / liquid separation accumulator located on the main loop A between the outlet of the second heat exchanger 5 and the inlet of the compression device 3. Said accumulator can receive at its inlet a two-phase mixture of refrigerant fluid. In steady state, the refrigerant fluid FR reaching the inlet of the accumulator is in the two-phase state and the refrigerant fluid FR leaving the outlet of the accumulator is in the saturated gas state.

[0040] The refrigerant circuit 1 comprises a non-return valve 11 located between the outlet of the second heat exchanger 5 and the junction point j1. Said non-return valve is configured to allow circulation of the refrigerant FR from the outlet of the second exchanger to the junction point j1 and to prohibit any circulation of the refrigerant FR from the junction point j1 to the outlet of the second exchanger 5.

[0041] The refrigerant circuit 1 comprises a second secondary branch C connecting a second branch point d2 to a second junction point j2, said second secondary branch successively comprising a third expansion member 12 and a fourth heat exchanger 13, arranged to be crossed by the flow of air inside the vehicle Fi and intended for the passenger compartment. The second derivation point d2 is located on the first derivation branch B between the first derivation point d1 and the second expansion member 8. According to an embodiment of the refrigerant circuit 1 not shown, the second branch point d2 is located between the first heat exchanger 4 and the first branch point d1. The second junction point j2 is located on the main loop A between the second heat exchanger 5 and the non-return valve 11. The fourth heat exchanger 13 is an evaporator arranged in the housing of a ventilation, heating and / or air conditioning (“HVAC”) installation (not shown) of which it forms part, upstream of the first heat exchanger 4 in the direction of circulation of the interior air flow Fi in this exemplary embodiment. The interior air flow Fi is circulated in the housing by means of a device for setting the interior air flow Fi in motion. The device for setting the interior air flow Fi in motion is, for example, a propeller set in rotation by an electric motor.

[0042] The refrigerant circuit 1 comprises a fourth expansion member 14 located between the first heat exchanger 4 and the bottle 10'.

[0043] The refrigerant circuit 1 comprises a three-way valve 15 located on the main loop A between the first heat exchanger 4 and the fourth expansion member 14, said three-way valve 15 having an inlet 15a, a first outlet 15b and a second outlet 15c. The main loop A comprises a passage through said three-way valve 15 from the inlet 15a to the outlet 15c according to the direction of travel of the refrigerant FR. The three-way valve 15 is configured so that the refrigerant FR circulates from the inlet 15a to the outlet 15b in certain operating modes of the circuit 1, and so that the refrigerant FR circulates from the inlet 15a to the outlet 15c in other operating modes of the circuit 1.

[0044] The refrigerant circuit 1 comprises a third secondary branch D connecting the outlet 15b of the three-way valve 15 to a third branch point d3 located on the main loop A between the second heat exchanger 5 and the first junction point j1, and more particularly between the second exchanger 5 and the second junction point j2.

[0045] The refrigerant circuit 1 comprises a fourth secondary branch E connecting a fourth bypass point d4 and a third junction point j3. Said fourth secondary branch E successively comprises a second non-return valve 16 and a fifth expansion member 17. The fourth bypass point d4 is located on the main loop A between the first expansion member 6 and the second heat exchanger 5. The third junction point j3 is located on the main loop A between the outlet 15c of the three-way valve 15 and the bottle 10'.

[0046] The refrigerant circuit 1 comprises a shut-off valve 18 located on the main loop A between the third bypass point d3 and the second junction point j2. The shut-off valve 18 is configured to allow the refrigerant FR to pass from the second heat exchanger 5 to the second junction point j2 in an open position of said shut-off valve 18, and to prevent the refrigerant FR from passing from the third bypass point d3 to the second junction point j2 in a closed position of said shut-off valve 18.

[0047] The expansion members 6, 8, 12, 14 and 17 are, for example, electronic expansion valves with variable opening section, in which the passage section allowing the refrigerant FR to pass can be continuously adjusted between a closed position and a maximum opening position. For this, an electronic control module of the expansion valve drives an electric motor which moves a movable shutter controlling the passage section offered to the refrigerant FR and thus modifying the pressure drop of the refrigerant FR passing through them. In the closed position, also called the closed position, the circulation of refrigerant FR is interrupted, that is to say that the flow rate of refrigerant FR passing through the electronic expansion valve is zero. The fourth and fifth expansion members 14 and 17 have a maximum opening position allowing the refrigerant FR to pass without expansion.

[0048] The thermal conditioning system comprises the LC heat transfer liquid circuit 200 comprising the bifluid heat exchanger 7 and the electric heating device 9. Said LC heat transfer liquid circuit 200 further comprises a pump 19 for circulating the LC heat transfer liquid within of the circuit 200, then forming a flow Fie of heat transfer liquid within said circuit 200 of heat transfer liquid LC.

[0049] The LC heat transfer fluid circuit 200 comprises an element 20 of the vehicle's powertrain. The element 20 of the powertrain is, for example, a battery and / or an electric motor. Depending on the operating mode of the circuit 200, the LC heat transfer fluid heats or cools the element 20 of the powertrain. Said element 20 of the powertrain is located between the two-fluid heat exchanger 7 and the electric heating device 9 depending on the direction of the heat transfer fluid flow Fie.

[0050] The thermal conditioning system 100 comprises a first temperature sensor T1 for measuring the outside temperature upstream of the second heat exchanger 5 according to the direction of circulation of the outside air flow Fe. An output signal of said first temperature sensor T1 for measuring the outside temperature Text is the value of said outside temperature Text.

[0051] The thermal conditioning system 100 comprises a second temperature sensor T2 for measuring the heat transfer fluid temperature Tfcs downstream of the first heat exchanger 4 according to the direction of circulation of the heat transfer fluid flow Ffc. An output signal of said second temperature sensor T2 for measuring the heat transfer fluid temperature Tfcs downstream of the first heat exchanger 4 is the value of said heat transfer fluid temperature Tfcs downstream of the first heat exchanger 4.

[0052] The thermal conditioning system 100 comprises a third temperature sensor T3 for measuring the temperature of the indoor air Taie downstream of the fourth heat exchanger 13 in the direction of circulation of the indoor air flow Fi. An output signal of said third temperature sensor T3 for measuring the temperature of the indoor air Taie downstream of the fourth heat exchanger 13 is the value of said outdoor temperature Taie. In this exemplary embodiment, the temperature of the indoor air downstream of the fourth heat exchanger 13 in the direction of circulation of the indoor air flow is also the temperature of the indoor air at the inlet of the first heat exchanger 4, the fourth heat exchanger 13 being arranged upstream of the first heat exchanger 4 in the direction of circulation of the indoor air flow Fi.

[0053] The refrigerant circuit 1 comprises a fourth temperature sensor T4 for measuring the Tree temperature of the refrigerant FR at the inlet of the compression device 3. An output signal of said fourth temperature sensor T4 for measuring the Tree temperature of the refrigerant FR at the inlet of the compression device 3 is the value of the Tree temperature at the inlet of the compression device 3.

[0054] The refrigerant circuit 1 comprises a pressure sensor P1 for measuring the pressure Prce of the refrigerant FR at the inlet of the compression device 3, said pressure sensor being located on the main loop A between the first junction point j1 and the inlet of the compression device 3. An output signal of said pressure sensor P1 for measuring the pressure Prce of the refrigerant FR at the inlet of the compression device 3 is the value of the pressure Prce at the inlet of the compression device 3.

[0055] According to an exemplary embodiment of the refrigerant circuit 1, said circuit 1 comprises a second pressure sensor P2, not shown, for measuring a pressure Prcds of the refrigerant FR at the outlet of the second heat exchanger 5, said sensor being located on the main loop A between the second heat exchanger 5 and the first junction point j1. An output signal of said second pressure sensor P2 for measuring the pressure Prcds of the refrigerant FR at the outlet of the second heat exchanger 5 is the value of the pressure Prcds at the outlet of the second heat exchanger 5.

[0056] The LC heat transfer liquid circuit 200 comprises a fifth temperature sensor T5 for measuring the temperature of the LC heat transfer liquid downstream of the electric heating device 9 in the direction of the flow of heat transfer liquid Fie. An output signal of said fifth temperature sensor T5 for measuring the temperature of the LC heat transfer liquid downstream of the electric heating device 9 is the value of said temperature of the LC heat transfer liquid downstream of the electric heating device 9.

[0057] According to one embodiment of the thermal conditioning system 100, the circuit 200 of heat transfer liquid LC comprises a sixth temperature sensor T6, not shown, for measuring the temperature of the heat transfer liquid LC downstream of the bifluid heat exchanger 7 according to the direction of the liquid flow. heat transfer fluid Fie. An output signal of said fifth temperature sensor T6 for measuring the temperature of the heat transfer fluid LC downstream of the two-fluid heat exchanger is the value of said temperature of the heat transfer fluid LC downstream of the two-fluid heat exchanger.

[0058] According to one embodiment of the thermal conditioning system 100, the thermal conditioning system 100 comprises a seventh temperature sensor T7, not shown, for measuring the heat transfer fluid temperature Tfce upstream of the first heat exchanger 4 according to the direction of circulation of the heat transfer fluid flow. An output signal of said seventh temperature sensor T7 for measuring the heat transfer fluid temperature Tfce upstream of the first heat exchanger 4 is the value of said heat transfer fluid temperature Tfce. The presence of this seventh temperature sensor T7 for measuring the heat transfer fluid temperature Tfce upstream of the first heat exchanger 4 makes sense in one embodiment of the thermal conditioning system 100 in which the heat transfer fluid flow Ffc and the indoor air flow Fi are two separate flows.

[0059] Figure 2 illustrates the exemplary embodiment of the thermal conditioning system 100 operating in a heating mode called “heat pump” mode, in which the outside air serves as a heat source to evaporate the refrigerant FR in the second heat exchanger 5, said heat taken by the second heat exchanger 5 being restored by the first heat exchanger 4 to the heat transfer fluid FC passing through it, thanks to the compression of the refrigerant FR within the compression device 3. In this exemplary embodiment, as already indicated previously, the heat transfer fluid flow Ffc is an internal air flow Fi intended for the cabin. In said “heat pump” mode, the refrigerant FR circulates only in the main loop A. Said refrigerant FR is compressed in the compression device 3, then passes through the first heat exchanger 4 in which it gives up heat to the internal air flow Fi passing through it.The refrigerant fluid FR then reaches the inlet 15a of the three-way valve 15, passes through said 3-way valve 15 and exits through the outlet 15c of said 3-way valve 15. The refrigerant fluid FR then passes through the fourth expansion member 14 in which it undergoes a first expansion. called pre-expansion, before entering the accumulation device 10. In this exemplary embodiment as already indicated previously, the accumulation device 10 is a gas / liquid separation bottle 10'. The refrigerant fluid FR at the outlet of the bottle 10' then enters the first expansion member 6 where it undergoes a second expansion called main expansion, before entering the second heat exchanger 5 where it evaporates and absorbs heat from the outside air flow Fe. The refrigerant fluid FR then passes through the stop valve 18, said stop valve 18 then being in an open position, then passes through the first non-return valve 11 before reaching the inlet of the compression device 3.

[0060] Figure 3 illustrates the exemplary embodiment of the thermal conditioning system 100 operating in a heating mode called “heat pump and electric heating” mode, in which on the one hand the electric heating device 9 is active and serves as a heat source for heating the heat transfer liquid LC and evaporating the refrigerant FR in the dual-fluid heat exchanger 7, and in which on the other hand the outside air serves as a heat source for evaporating the refrigerant FR in the second heat exchanger 5, all of the heat taken by the dual-fluid heat exchanger 7 and by the second heat exchanger 5 being restored by the first heat exchanger 4 to the heat transfer fluid FC passing through it, thanks to the compression of the refrigerant FR within the compression device 3. In said “heat pump and electric heating” mode, the refrigerant FR circulates in the main loop A and in the first secondary branch B. Said refrigerant FR is compressed in the compression device 3, then passes through the first heat exchanger 4 in which it transfers heat to the internal air flow Fi passing through it. The refrigerant FR then reaches the inlet 15a of the three-way valve 15, passes through said 3-way valve 15 and leaves through the outlet 15c of said 3-way valve 15. The refrigerant FR then passes through the fourth expansion member 14 in which it undergoes a first expansion called pre-expansion, before entering the accumulation device 10. In this exemplary embodiment as already indicated previously, the accumulation device 10 is a gas / liquid separation bottle 10'.The total flow of refrigerant fluid FR at the outlet of the 10' bottle is separated into a first flow of refrigerant fluid FR and a second. refrigerant fluid flow FR at the first branch point d1. The first flow enters the first expansion member 6 where it undergoes a second expansion called main expansion, before entering the second heat exchanger 5 where it evaporates and absorbs heat from the outside air flow Fe. Said first fluid flow then passes through the stop valve 18, said stop valve 18 then being in an open position, then passes through the first non-return valve 11 before reaching the first junction point j1. The second fluid flow takes the first secondary branch B from the branch point d1 and reaches the second expansion member 8 where it undergoes expansion before entering the two-fluid heat exchanger 7 where it evaporates and absorbs heat from the heat transfer liquid flow Fie. Said second fluid flow then reaches the first junction point j1. The first flow mixes with the second flow at the junction point j1.The total flow of refrigerant fluid FR then returns to the inlet of the compression device 3. Within the heat transfer circuit 200, the pump 19 circulates the heat transfer liquid LC to create a flow of heat transfer fluid Fie successively passing through the electric heating device 9 and the two-fluid heat exchanger 7. The electric heating device being active and heating the heat transfer liquid LC when it passes through it.

[0061] Figure 4 illustrates the exemplary embodiment of the thermal conditioning system 100 operating in a mode called “electric heating” mode, in which the electric heating device is active and serves as a heat source for heating the heat transfer fluid LC and evaporating the refrigerant fluid FR in the dual-fluid heat exchanger, the heat being restored by the first heat exchanger to the heat transfer fluid FC passing through it, thanks to the compression of the refrigerant fluid FR within the compression device 3, without circulation of refrigerant fluid FR within the second heat exchanger 5. In said “electric heating” mode, the refrigerant FR circulates in a part of the main loop A and in the first secondary branch B. Said refrigerant FR is compressed in the compression device 3, then passes through the first heat exchanger 4 in which it gives off heat to the internal air flow Fi passing through it. The refrigerant FR then reaches the inlet 15a of the three-way valve 15, passes through said 3-way valve 15 and leaves through the outlet 15c of said 3-way valve 15. The refrigerant fluid FR then passes through the fourth expansion member 14 in which it undergoes a first expansion called pre-expansion, before entering the accumulation device 10. In this exemplary embodiment as already indicated previously, the accumulation device 10 is a gas / liquid separation bottle 10'. The refrigerant fluid FR takes the first secondary branch B from the branch point d1 and joins the second expansion member 8 where it undergoes an expansion before entering the two-fluid heat exchanger 7 where it evaporates and absorbs heat from the flow of heat transfer liquid Fie. The refrigerant fluid FR then reaches the inlet of the compression device 3. Within the heat transfer circuit 200, the pump 19 circulates the heat transfer liquid LC to create a flow of heat transfer fluid Fie successively passing through the electric heating device 9 and the two-fluid heat exchanger 7.The electric heating device is active and heats the heat transfer fluid LC when it passes through it.

[0062] Figure 5 illustrates an example of mode choice mapping between the “heat pump” mode, the “heat pump and electric heating” mode and the “electric heating” mode, applied by the method 2 according to one aspect of the invention, and depending at least on a set heating power HC and the outside temperature Text.

[0063] In at least a first outside temperature interval 11,11', the heating mode is chosen according to said mapping, this choice is not modified as long as the outside temperature remains in said first outside temperature interval 11,IT. When the outside temperature Text is for example less than -20°, the mode chosen is the "electric heating" mode.

[0064] In at least a second outside temperature interval I2, for example between -20°C and 0°C, the initial heating mode is chosen initially according to said at least one map depending on the outside temperature Text and the set heating power HC, then in a second time according to conditions for switching from one heating mode to another. During operation of the thermal conditioning system 100, the choice of mode is again applied according to the map as soon as the outside temperature Text and / or the set heating power are modified since the last choice from the mapping and suggest a change of mode according to said mapping. In said second temperature interval I2, as long as the outside temperature Text and the set heating power HC are fixed, the method 2 checks conditions for switching from a heating mode to according to an aspect of the method 2 of the invention.

[0065] In the at least first interval 11, IT of outside temperature Text, the mapping indicates the operating mode to be executed which is capable of achieving the desired heating performance with the least possible electrical consumption. Electrical consumption is understood to mean the sum of the consumption of the compression device 3 and the electric heating device 9. In the at least second interval I2 of outside temperature Text, the mapping indicates initially as a first approximation the operating mode to be executed which is capable of achieving the desired heating performance with the least possible consumption. It is then the verifications of criteria of conditions for switching from one mode to another which specify in a second step the operating mode to be executed which is capable of achieving the desired heating performance with the least possible consumption.

[0066] The mapping is defined in advance and saved in a memory of the central control unit UC.

[0067] The preliminary definition of said mapping is based, for example, on theoretical calculations and / or laboratory tests and / or in real conditions.

[0068] Method 2 determines the outside temperature Text. In this exemplary embodiment of the thermal conditioning system 100, the outside temperature Text is measured with the first temperature sensor T1 for measuring the outside temperature Text upstream of the second heat exchanger 5 according to the direction of circulation of the outside air flow Fe.

[0069] In this example of the thermal conditioning system 100 of embodiment of the thermal conditioning system 100, the method 2 determines the set heating power from a level value Lvl of the blower of the heating, ventilation and / or air conditioning installation of the vehicle communicated by a vehicle messaging network, from the internal air heating setpoint temperature value Tsp downstream of the first heat exchanger 4, and from the temperature value Taie upstream of the first heat exchanger 4.

[0070] An internal air flow Qai is evaluated from the Lvl level of the blower using a matrix defined beforehand and stored in the memory of the central control unit UC. Said matrix indicates a Qai flow rate according to the Lvl level of the blower and according to, for example, a temperature of the internal air flow and / or the air distribution chosen at the outlet of the heating, ventilation and / or air conditioning installation.

[0071] In this exemplary embodiment of the thermal conditioning system 100, the internal air temperature T1e upstream of the first heat exchanger 4 is determined with the third temperature sensor T3 for measuring the internal air temperature downstream of the third heat exchanger 13. Indeed, the arrangement of the first heat exchanger 4 and the third heat exchanger 13 within the heating, ventilation and / or air conditioning installation is such that the downstream of the third heat exchanger 13 is the upstream of the first heat exchanger 4.

[0072] Figure 5 is a flowchart illustrating the steps of method 2 according to one aspect of the invention. Method 2 includes a preliminary step of choosing the heating mode according to the mapping. - When the outside temperature Text is for example equal to or lower than -20°C, called the first cold interval 11, the “electric heating” mode is chosen. This choice remains valid as long as the outside temperature Text remains lower than or equal to -20°C. - When the outside temperature Text is for example equal to or greater than 0°C, called first hot interval IT hot, “heat pump” mode is chosen. This choice remains valid as long as the outside temperature Text remains greater than or equal to 0°C. - When the temperature is between, for example, -20°C and 0°C, known as the second interval I2, the heating mode chosen depends on the mapping, in particular on the value of the outside temperature Text and the set heating power HC.

[0073] Once a heating mode is chosen from the mapping in said second temperature interval I2, the method 2 applies steps to ensure that the heating mode currently being executed is indeed the heating mode capable of reaching the set heating power with the minimum possible electrical consumption, or if a change of mode to a mode capable of reaching the set heating power or capable of reaching the set heating power with a consumption lower than that of the heating mode currently being executed is necessary.

[0074] When the mode being executed is the “electric heating” mode and the outside temperature Text is in the second temperature interval I2, for example between -20°C and 0°C, method 2 comprises the following steps: - a step of determining a value of a representative quantity G of an evaporation temperature Tev of the refrigerant fluid FR in the second heat exchanger 5, - a step of determining the outside temperature Text, - a comparison step between the value of the representative quantity G of the evaporation temperature Tev of the refrigerant fluid FR in the second heat exchanger 5 with a first threshold value G* depending on the outside temperature Text, A condition for switching from the “electric heating” mode to the “electric heating and heat pump” mode is that the value of the representative quantity G of the evaporation temperature of the refrigerant fluid FR in the second heat exchanger 5 crosses the first threshold value G* in a first direction. According to distinct embodiments, the representative quantity G of the evaporation temperature of the refrigerant fluid FR in the second heat exchanger 5 is one of the following quantities: • a pressure of the refrigerant fluid FR at the outlet of the second heat exchanger 5, • an evaporation pressure of the refrigerant fluid FR in the second heat exchanger 5, • a pressure of the refrigerant fluid FR at the inlet of the second heat exchanger 5, • an interpolation pressure of the refrigerant fluid FR between the inlet and the outlet of the second heat exchanger 5, • a temperature of the refrigerant fluid FR at the outlet of the second heat exchanger 5, • an evaporation temperature of the refrigerant fluid FR in the second heat exchanger 5, • a temperature of the refrigerant fluid FR at the inlet of the second heat exchanger 5, • an interpolation temperature of the refrigerant fluid FR between the inlet and the outlet of the second heat exchanger 5, In the embodiment described here, the representative quantity G of the evaporation temperature Tev of the refrigerant fluid FR in the second heat exchanger 5 is an evaporation pressure Pev of the refrigerant fluid FR in the second heat exchanger 5. In said embodiment, the first threshold value G* of the representative quantity is a first threshold pressure P* equal to the saturation pressure of the refrigerant fluid FR at the outside temperature Text, minus k with k which is a constant between 0.15 bar and 0.25 bar and preferably equal to 0.2 bar. The pressure Pev of the refrigerant fluid FR is advantageously determined by calculation from the pressure Prce of the refrigerant fluid FR at the inlet of the compression device 3 and the value of a pressure drop Ap of the refrigerant fluid FR between the second heat exchanger 5 and the inlet of the compression device 3, in this direction of circulation, depending on a flow rate Qref of refrigerant fluid circulating between the outlet of the second heat exchanger 5 and the inlet of the compression device 3. According to one aspect of the invention, the flow rate Qref of refrigerant fluid FR circulating between the outlet of the second heat exchanger 5 and the inlet of the compression device 3 is estimated from a speed Ncp of the compression device 3 and the pressure Prce of the refrigerant fluid FR at the inlet of the compression device 3. According to another aspect of the invention, the flow rate Qref of refrigerant fluid FR circulating between the outlet of the second heat exchanger 5 and the inlet of the compression device 3 is estimated from the speed Ncp of the compression device 3, the pressure Prce of the refrigerant fluid FR at the inlet of the compression device 3 and the temperature Tree of the refrigerant fluid FR at the inlet of the compression device 3. According to another embodiment of the circuit 1 and the method 2, the evaporation pressure Pev in the second heat exchanger 5 is determined from the measurement made by the second pressure sensor P2 (not shown) for measuring the pressure Prcds of the refrigerant fluid FR at the outlet of the second heat exchanger 5. It is then considered that the evaporation pressure Pev in the second heat exchanger 5 is equal to the pressure Prcds of the refrigerant fluid FR at the outlet of the second heat exchanger 5. The condition for switching from “electric heating” mode to “electric heating and heat pump” mode is that the pressure Pev of the refrigerant fluid FR in the second heat exchanger 5 is lower than the first threshold pressure value P*. According to another embodiment, the representative quantity G is an evaporation temperature Tev of the refrigerant fluid FR in the second heat exchanger 5. In said other embodiment, the first threshold value G* of the representative quantity is a threshold temperature T* equal to the outside temperature Text minus x with x which is a constant between 1.5°C and 2.5°C and preferably equal to 2°C. In said other embodiment, the condition for switching from the “electric heating” mode to the “electric heating and heat pump” mode is that the evaporation temperature Tev of the refrigerant fluid FR in the second heat exchanger 5 is lower than the threshold temperature value T*. In said other embodiment, the evaporation temperature Tev in the second heat exchanger 5 is advantageously measured by a temperature sensor not shown. Method 2 executes the transition from the "electric heating" mode to the "electric heating and heat pump" mode when the condition for transitioning from the "electric heating" mode to the "electric heating and heat pump" mode is met. Thus, the condition for transitioning from the "electric heating" mode to the "electric heating and heat pump" mode is necessary. In this example of implementation of method 2, the condition for transitioning from the "electric heating" mode to the "electric heating and heat pump" mode is necessary and sufficient. This aspect of the invention makes it possible to switch from the “electric heating” mode to the “electric heating and heat pump” mode when it turns out that the “electric heating and heat pump” mode is capable of ensuring the required heating performance, while consuming less than the “electric heating” mode.

[0075] When the mode being executed is the “electric heating and heat pump” mode and the outside temperature Text is in the second temperature interval I2, for example between -20°C and 0°C, the method 2 comprises the following steps: a step of determining the value of the representative quantity G of the evaporation temperature of the refrigerant fluid FR in the second heat exchanger 5, - a step of determining the outside temperature Text, - a comparison step between the value of the representative quantity G of the evaporation temperature of the refrigerant fluid FR in the second heat exchanger 5 with a second threshold value G** depending on the outside temperature Text, - a step of determining the temperature Tfcs of the heat transfer fluid passing through the first heat exchanger 4, downstream of said first heat exchanger 4, - a comparison step between the temperature Tfcs of the heat transfer fluid downstream of the first heat exchanger 4 and a heating setpoint temperature value Tsp communicated by the vehicle. The method 2 comprises a condition for switching from the “electric heating and heat pump” mode to the “electric heating” mode, said switching condition being that the value of the representative quantity G of the evaporation temperature of the refrigerant fluid FR in the second heat exchanger 5 crosses a second threshold value G** in a second direction, opposite to the first direction. In the embodiment described here, the representative quantity G of the evaporation temperature of the refrigerant fluid FR in the second heat exchanger 5 is the evaporation pressure Pev of the refrigerant fluid FR at the outlet of the second heat exchanger 5. In said embodiment, the second threshold value G** of the representative quantity is a second threshold pressure value P** equal to the saturation pressure of the refrigerant fluid FR at the outside temperature Text, plus a value k' with k' which is a constant between 0.05 bar and 0.2 bar and preferably equal to 0.1 bar. In said embodiment, the condition for switching from the “electric heating and heat pump” mode to the “electric heating” mode is that the evaporation pressure Pev of the refrigerant fluid FR in the second heat exchanger 5 is greater than the second threshold pressure value ** According to another embodiment, the representative quantity G is the evaporation temperature Tev of the refrigerant fluid FR in the second heat exchanger 5. In said other embodiment, the second threshold value G** of the representative quantity is a threshold temperature T** equal to the outside temperature Text + x' with x' which is a constant between 0.5°C and 2°C and preferably equal to 1°C. In said other embodiment, the condition for switching from the “electric heating and heat pump” mode to the “electric heating” mode is that the evaporation temperature Tev of the refrigerant fluid FR in the second heat exchanger 5 is greater than the threshold temperature value T**. In said other embodiment, the evaporation temperature Tev in the second heat exchanger 5 is advantageously measured by a temperature sensor not shown. Method 2 executes the transition from the “electric heating and heat pump” mode to the “electric heating” mode when the condition for transitioning from the “electric heating and heat pump” mode to the “electric heating” mode is met. The condition for switching from “electric heating and heat pump” mode to “electric heating” mode is sufficient for switching from “electric heating and heat pump” mode to “electric heating” mode. This aspect of the invention makes it possible to switch from the “electric heating and heat pump” mode to the “electric heating” mode when it turns out that the “electric heating and heat pump” mode is not capable of ensuring the required heating performance while respecting the constraints of circuit 1 or when the “electric heating” mode is capable of ensuring the same heating performance while consuming less than the “electric heating and heat pump” mode. Method 2 comprises a condition for switching from the “electric heating and heat pump” mode to the “heat pump” mode, said switching condition being that the value of the heat transfer fluid temperature Tfcs downstream of the first heat exchanger is greater than the temperature heating setpoint Tsp + a, with a being a constant having a value between 0.5°C and 2°C and preferably equal to 1°C, Method 2 executes the transition from the “electric heating and heat pump” mode to the “heat pump” mode when the condition for transitioning from the “electric heating and heat pump” mode to the “heat pump” mode is met. The condition for switching from the “electric heating and heat pump” mode to the “heat pump” mode is necessary for switching from the “electric heating and heat pump” mode to the “heat pump” mode. In this exemplary embodiment of method 2, said condition for switching from the “electric heating and heat pump” mode to the “heat pump” mode is necessary and sufficient. This aspect of the invention makes it possible to switch from the “electric heating and heat pump” mode to the “heat pump” mode when it turns out that the “heat pump” mode is capable of ensuring the required heating performance with lower electrical consumption than the “electric heating and heat pump” mode.

[0076] When the running mode is the "heat pump" mode and the outside temperature Text is in the second temperature interval I2, for example between -20°C and 0°C, method 2 comprises the following steps: - a step of determining the pressure Prce of the refrigerant fluid FR at the inlet of the compression device 3, - a comparison step between the pressure Prce of the refrigerant fluid FR at the inlet of the compression device with a minimum threshold value of pressure Prce_min at the inlet of the compression device 3 recorded in the memory of the central control unit UC, - a step of determining the temperature Tfcs of the heat transfer fluid passing through the first heat exchanger 4, downstream of said first heat exchanger 4, - a comparison step between the temperature Tfcs of the heat transfer fluid downstream of the first heat exchanger 4 and the heating setpoint temperature value Tsp communicated by the vehicle. - a comparison step between the speed Ncp of the compression device 3 and a maximum speed threshold value Ncp_max recorded in the memory of the central control unit UC. The method 2 comprises a first condition for switching from the “heat pump” mode to the “electric heating and heat pump” mode, said first switching condition being that the temperature Tfcs of the heat transfer fluid downstream of the first heat exchanger 4 is lower than the heating setpoint temperature Tsp - a, with a being a constant having a value between 0.5°C and 2°C, and preferably equal to 1°C. The method 2 comprises a second condition for switching from the “heat pump” mode to the “electric heating and heat pump” mode, said second switching condition being that the speed Ncp of the compression device is equal to the maximum speed threshold value Ncp_max or that the pressure Prce at the inlet of the compression device 3 is equal to or less than the minimum pressure threshold value Prce_min at the inlet of the compression device 3. Method 2 executes the transition from the “heat pump” mode to the “electric heating and heat pump” mode when at least the first condition for transitioning from the “heat pump” mode to the “electric heating and heat pump” mode and the second condition for transitioning from the “heat pump” mode to the “electric heating and heat pump” mode are met. The first and second conditions for switching from “heat pump” mode to “electric heating and heat pump” mode are necessary for switching from “heat pump” mode to “electric heating and heat pump” mode. This aspect of the invention makes it possible to switch from the “heat pump” mode to the “electric heating and heat pump” mode when it turns out that the “heat pump” mode is not capable of ensuring the required heating performance while respecting the constraints of refrigerant circuit 1.

[0077] Regardless of the mode currently being executed, method 2 executes a change of heating mode according to the mapping as soon as a change in the outside temperature Text and / or the set heating power HC since the time of the previous choice from the mapping justifies said change of mode according to said mapping.

Claims

Claims

1. Method (2) for controlling a thermal conditioning system (100) of a vehicle, said system comprising a circuit (1) of refrigerant fluid (FR), said circuit (1) of refrigerant fluid (FR) comprising: a main loop (A), said main loop (A) successively comprising, according to the direction of circulation of the refrigerant fluid: -- a compression device (3) for the refrigerant fluid (FR), -- a first heat exchanger (4) arranged to be crossed by a flow (Ffc) of a heat transfer fluid (FC) and intended to heat said heat transfer fluid (FC), -- a second heat exchanger (5) located between the first heat exchanger (4) and the compression device (3), arranged to be crossed by a flow of air (Fe) outside the vehicle and intended in particular to evaporate the refrigerant fluid (FR), -- a first expansion member (6) located between the first heat exchanger (4) and the second heat exchanger (5), - a first secondary branch (B), connecting a first branch point (d1) to a first junction point (j1), said first secondary branch (B) successively comprising, according to the direction of circulation of the refrigerant fluid, a second expansion member (8) and a two-fluid heat exchanger (7) arranged in a circuit (200) of heat transfer fluid (LC) and intended to evaporate the refrigerant fluid (FR), said first branch point (d1) being located between the first heat exchanger (4) and the first expansion member (6), said first junction point (j1) being located between the second heat exchanger (4) and the compression device (3), said circuit (200) of heat transfer fluid (LC) comprising an electric heating device (9) for heating said heat transfer fluid (LC), said thermal conditioning system (100) being configured to operate in an “electric heating” mode, in a “heat pump” mode or in an “electric heating and heat pump” mode: - said “electric heating” mode being a mode in which the electric heating device (9) is active and serves as a heat source for heating the heat transfer fluid (LC) and evaporating the refrigerant fluid (FR) in the bifluid heat exchanger (7), the heat being restored by the first heat exchanger (4) to the heat transfer fluid (FC) passing through it, thanks to the compression of the refrigerant fluid (FR) within the compression device (3), and in which the second heat exchanger (5) is inactive, said “heat pump” mode being a mode where the outside air serves as a heat source to evaporate the refrigerant fluid (FR) in the second heat exchanger (5), said heat taken by the second heat exchanger (5) being restored by the first heat exchanger (4) to the heat transfer fluid (FC) passing through it, thanks to the compression of the refrigerant fluid (FR) within the compression device (3), and in which the two-fluid heat exchanger (7) is inactive, - said “electric heating and heat pump” mode being a mode in which on the one hand the electric heating device (9) is active and serves as a heat source for heating the heat transfer fluid (LC) and evaporating the refrigerant fluid (FR) in the two-fluid heat exchanger (7), and in which on the other hand the outside air serves as a heat source for evaporating the refrigerant fluid (FR) in the second heat exchanger (5), all of the heat taken by the two-fluid heat exchanger (7) and by the second heat exchanger (5) being restored by the first heat exchanger (4) to the heat transfer fluid (FC) passing through it, thanks to the compression of the refrigerant fluid (FR) within the compression device (3), said method (2) comprising: a step of determining a value of a quantity representative (G) of an evaporation temperature (Tev) of the refrigerant fluid (FR) in the second heat exchanger (5), - a step of determining an exterior temperature of the vehicle (Text), - a comparison step between the value of the representative quantity (G) of the evaporation temperature (Tev) of the refrigerant fluid (FR) in the second heat exchanger (5) with a first threshold value (G*), - a condition for switching from the “electric heating” mode to the “electric heating and heat pump” mode, said switching condition being that the representative quantity (G) of the evaporation temperature (Tev) of the refrigerant fluid (FR) in the second heat exchanger (5) crosses the first threshold value (G*) in a first direction. the method executing the switch from the “electric heating” mode to the “electric heating and heat pump” mode when said condition for switching from the “electric heating” mode to the “electric heating and heat pump” mode is fulfilled.

2. Control method (2) according to the preceding claim in which the representative quantity (G) of the evaporation temperature (Tev) of the refrigerant fluid (FR) in the second heat exchanger (5) is a pressure (Pev) of the refrigerant fluid (FR) in the second heat exchanger (5), said first threshold value (G*) being a first threshold pressure value (P*), equal to the saturation pressure of the refrigerant fluid (FR) at the temperature outside the vehicle (Text) minus (k) with (k) which is a constant between 0.15 bar and 0.25 bar and preferably equal to 0.2 bar, said condition for switching from the “electric heating” mode to the “electric heating and heat pump” mode being that the pressure (Pev) of the refrigerant fluid (FR) in the second heat exchanger (5) is lower than the first threshold pressure value (P*).

3. Control method (2) according to claim 1 in which the representative quantity (G) of the evaporation temperature (Tev) of the refrigerant fluid (FR) in the second heat exchanger (5) is the evaporation temperature (Tev) of the refrigerant fluid (FR) in the second heat exchanger (5), said first threshold value (G*) being a first threshold temperature value (T*), equal to the temperature outside the vehicle (Text) minus (x) with (x) which is a constant between 1.5°C bar and 2.5°C and preferably equal to 2°C, said condition for switching from “electric heating” mode to “electric heating and heat pump” mode being that the temperature (Tev) of the refrigerant fluid (FR) in the second heat exchanger (5) is lower than the value of the first threshold temperature (T*).

4. A method (2) of control according to any one of the preceding claims comprising: - a condition for switching from the “electric heating and heat pump” mode to the “electric heating” mode, said switching condition being that the representative quantity (G) of the evaporation temperature (Tev) of the refrigerant fluid (FR) in the second heat exchanger (5) crosses a second threshold value (G**) in a second direction, opposite to the first direction, in which said method (2) executes the switch from the “electric heating and heat pump” mode to the “heat pump” mode when the condition for switching from the “electric heating and heat pump” mode to the “heat pump” mode is fulfilled.

5. Control method (2) according to the preceding claim in which the representative quantity (G) of the evaporation temperature (Tev) of the refrigerant fluid (FR) in the second heat exchanger (5) is a pressure (Pev) of the refrigerant fluid (FR) in the second heat exchanger (5), said second threshold value (G**) being a second threshold pressure value (P**), equal to the saturation pressure of the refrigerant fluid (FR) at the temperature outside the vehicle (Text) plus (k') with (k') which is a constant between 0.05 bar and 0.2 bar and preferably equal to 0.1 bar, said condition for switching from the "electric heating and heat pump" mode to the "electric heating" mode being that the pressure (Pev) of the refrigerant fluid (FR) in the second heat exchanger (5) is greater than the second threshold pressure value (P**).

6. Control method (2) according to claim 4 in which the representative quantity (G) of the evaporation temperature (Tev) of the refrigerant fluid (FR) in the second heat exchanger (5) is the evaporation temperature (Tev) of the refrigerant fluid (FR) in the second heat exchanger heat (5), said second threshold value (G**) being a second threshold temperature value (T**), equal to the temperature outside the vehicle (Text) plus (x') with (x') which is a constant between 0.5°C bar and 2°C and preferably equal to 1°C, said condition for switching from the “electric heating and heat pump” mode to the “electric heating” mode being that the temperature (Tev) of the refrigerant (FR) in the second heat exchanger (5) is greater than the second threshold temperature value (T**).

7. A method (2) of control according to any one of the preceding claims comprising: - a step of determining a temperature (Tfcs) of heat transfer fluid (FC) passing through the first heat exchanger (4), downstream of said first heat exchanger (4), - a comparison step between the temperature (Tfcs) of the heat transfer fluid (FC) downstream of the first heat exchanger (4) and a heating setpoint temperature value (Tsp), - a condition for switching from the “electric heating and heat pump” mode to the “heat pump” mode, said switching condition being that the value of the temperature (Tfse) of the heat transfer fluid downstream of the first heat exchanger (4) is greater than the heating setpoint temperature (Tsp) + a, with a being a constant having a value between 0.5°C and 2°C and preferably equal to 1°C, in which said method (2) executes the switching from the “electric heating and heat pump” mode to the “heat pump” mode when the condition for switching from the “electric heating and heat pump” mode to the “heat pump” mode is fulfilled.

8. Control method (2) according to the preceding claim comprising: a step of comparison between the speed (Ncp) of the compression device (3) and a maximum speed threshold value (Ncp_max), - a comparison step between the pressure (Prce) of the refrigerant fluid (FR) at the inlet of the compression device (3) with a minimum pressure threshold value (Prece_min) at the inlet of the compression device (3), - a first condition for switching from the “heat pump” mode to the “electric heating and heat pump” mode, said first switching condition being that the temperature (Tfcs) of the heat transfer fluid downstream of the first heat exchanger (4) is lower than the heating setpoint temperature (Tsp) - a, with a being a constant having a value between 0.5°C and 2°C, and preferably equal to 1°C. - a second condition for switching from the “heat pump” mode to the “electric heating and heat pump” mode, said second switching condition being that the speed (Ncp) of the compression device is equal to the maximum speed threshold value (Ncp_max) or that the pressure (Prce) at the inlet of the compression device (3) is equal to or less than the minimum pressure threshold value (Prce_min) at the inlet of the compression device (3), in which said method (2) executes the switching from the “heat pump” mode to the “electric heating and heat pump” mode when at least the first condition for switching from the “heat pump” mode to the “electric heating and heat pump” mode and the second condition for switching from the “heat pump” mode to the “electric heating and heat pump” mode are met.

9. Control method (2) according to any one of the preceding claims comprising a mapping of choice of a mode from among the “electric heating”, “electric heating and heat pump” and “heat pump” modes.

10. Control method (2) according to the preceding claim in which the mapping depends on a set heating power (HC) and the outside temperature (Text).

11. Control method (2) according to the preceding claim in which in at least a first interval (11; 11') of outside temperature, the heating mode is chosen according to said mapping, this choice not being modified as long as the outside temperature (Text) remains in said first outside temperature interval (11; IT), and in which in at least a second outside temperature interval (I2), the heating mode is chosen according to said mapping, then according to said conditions for switching from one heating mode to another.

12. Control method (2) according to the preceding claim in which in said second outside temperature interval (I2), a change in the outside temperature (Text) and / or in the set heating power (HC) causes a change of mode according to said mapping.

13. Method (2) for controlling a thermal conditioning system (100) of a vehicle according to any one of the preceding claims, the circuit (1) comprising a reserve device (10) of refrigerant fluid (FR) in the main loop (A) located between the first heat exchanger (4) and the compression device (3).

14. A computer program comprising instructions that cause the thermal conditioning system (100) to execute the control method (2) according to any one of the preceding claims.

15. Thermal conditioning system 100 according to the preceding claim comprising a central control unit (UC), said unit (UC) comprising at least one computer, a memory and the computer program stored in the memory.

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