Thermal system for motor vehicles.

Abstract

Thermal system for motor vehicles.Thermal management method for a motor vehicle equipped with ducts arranged to allow circulation of a heat transfer fluid in a loop successively connecting an electric heating element, a condenser of a heat pump and then an air heater, the thermal management method comprising: - a first step of receiving a first desired temperature in a passenger compartment of the motor vehicle, - a second step of determining a second current temperature of the passenger compartment of the motor vehicle, - a third step of transmitting to the heat pump a first temperature setpoint of the heat transfer fluid and transmitting to the electric heating element a second temperature setpoint of the heat transfer fluid, the first and second setpoints being calculated as a function of the first temperature and the second temperature, the difference between the first setpoint and the second setpoint being strictly positive.Figure for the abridged version: 4.

Description

Title of the invention: Thermal system for a motor vehicle.

[0001] The invention relates to a method for thermal management of a motor vehicle. The invention also relates to a thermal system for a motor vehicle. The invention further relates to a motor vehicle equipped with a thermal system.

[0002] Motor vehicles, and particularly electric vehicles, can be equipped with a heat pump, which has excellent energy efficiency. However, below a temperature threshold, for example below -10°C, the power supplied by the heat pump alone is insufficient to heat the passenger compartment.

[0003] Additional heating is then necessary, generally implemented by an electric heating element arranged on the heat transfer fluid circuit upstream or downstream of the heat pump. The efficiency of the electric heating element being much less advantageous than that of the heat pump, its use is regulated, in particular its use is preferentially stopped in favor of the heat pump, as soon as the desired temperature of the heat transfer fluid is reached.

[0004] In the case of an indirect heat pump, that is to say when the condenser of the heat pump exchanges the heat produced with the heat transfer fluid of a heating circuit, the simultaneous control of the electrical element and the heat pump is complex because these two systems are arranged on the same heat transfer fluid circulation loop, which creates an interdependence between the two systems and leads to a very significant risk of instability in the regulation of the two systems.

[0005] The aim of the invention is to provide a thermal management method and a thermal system which overcomes the above drawbacks and improves the methods and systems known from the prior art. In particular, the invention makes it possible to provide a thermal management method which is reliable and efficient, which effectively regulates the use of the electrical element while eliminating the risk of instability in the regulation of the two heating systems.

[0006] To this end, the invention relates to a method for thermal management of a motor vehicle equipped - an electric heating element, - an air heater, - a heat pump including a condenser, - and a first set of conduits arranged so as to allow circulation of a first heat transfer fluid in a loop of conduits successively connecting the electric heating element, the condenser and then the air heater, the thermal management method comprising: - a first step of receiving a first desired temperature in a passenger compartment of the motor vehicle, - a second step of determining a second current temperature of the passenger compartment of the motor vehicle, - a third step of transmitting to the heat pump a first temperature setpoint of the first heat transfer fluid and transmitting to the electric heating element a second temperature setpoint of the first heat transfer fluid, the first and second setpoints being calculated as a function of the first temperature and the second temperature, a difference between the first instruction and the second instruction being strictly positive, in particular strictly greater than one degree Celsius, or even strictly greater than two degrees Celsius, or even strictly greater than three degrees Celsius.

[0007] In one embodiment, the difference between the first setpoint and the second setpoint is equal to a constant positive threshold, for example 3 degrees Celsius.

[0008] In one embodiment, the second step comprises determining the second temperature - as a function of a third temperature of a heat transfer fluid circulating at the inlet of the air heater measured by a first temperature sensor, and / or - depending on a fourth temperature of air circulating at the inlet of the air heater measured by a second temperature sensor, and / or - depending on the flow rate of air passing through the heater, and / or - depending on the thermal characteristics of the air heater.

[0009] In one embodiment, the calculation of the first temperature setpoint of the first heat transfer fluid comprises: - a calculation of a first difference between the first temperature and the second temperature, then - an implementation of a proportional, integral, derivative type regulator, determining a first temperature setpoint of the first heat transfer fluid canceling the first deviation.

[0010] In one embodiment, the heat pump comprises a second set of conduits arranged so as to allow circulation of a second heat transfer fluid in the condenser, the method comprises a fourth step of calculating a flow rate of the second heat transfer fluid in the condenser, comprising: - a calculation of a second difference between the first temperature setpoint of the first heat transfer fluid and a current temperature of the first heat transfer fluid, then - an implementation of a proportional, integral, derivative type regulator determining a flow rate setpoint for the second heat transfer fluid canceling the second difference.

[0011] In one embodiment, the fourth step further comprises a calculation of an electrical power required to cancel a temperature difference between the second setpoint and a current temperature of the first heat transfer fluid, comprising - a calculation of a third difference between the second temperature setpoint of the first heat transfer fluid and a current temperature of the first heat transfer fluid, then - an implementation of a proportional, integral, derivative type regulator determining a power setpoint for the electric heating element canceling the third deviation.

[0012] The invention further relates to a thermal management system comprising hardware and / or software elements implementing the method according to the invention, in particular hardware and / or software elements designed to implement a method according to the invention, and / or the device comprising means for implementing the method according to the invention.

[0013] In one embodiment of the thermal management system, the electric heating element is a ceramic resistor known as a positive temperature coefficient resistor.

[0014] The invention further relates to a motor vehicle equipped with a thermal system according to the invention.

[0015] [Fig.l] schematically represents a motor vehicle equipped with a thermal system according to one embodiment of the invention.

[0016] [Fig.2] is a flowchart representing a mode of execution of a thermal management method according to the invention.

[0017] [Fig.3] illustrates an embodiment of a calculation of a power applied by an electric heating element of the thermal management system.

[0018] [Fig.4] illustrates a first implementation of a thermal system according to the invention when an outside air temperature is 0°C.

[0019] [Fig.5] illustrates a second implementation of a thermal system according to the invention when an outside air temperature is -15°C.

[0020] An embodiment of a motor vehicle 100 according to the invention is described below with reference to [Fig.l]. The motor vehicle 100 is a motor vehicle of any type, in particular a passenger vehicle or a utility vehicle.

[0021] In an embodiment more specifically described in this document, the motor vehicle 100 is an electric vehicle, that is to say a vehicle comprising an electric motor configured to drive drive wheels of the vehicle. It comprises a thermal system 1 intended in particular for heating a passenger compartment 2 of the vehicle.

[0022] The thermal system 1 comprises a first set 10 of conduits in which a first heat transfer fluid circulates. The conduits of the first assembly 10 are connected to a pump 16 which creates a circulation of fluid in the conduits of the first assembly 10. The thermal circuit 1 may also include a degassing tank.

[0023] The thermal system 1 notably comprises an air heater 12, also called a heating radiator, arranged in the passenger compartment 2.

[0024] At least one conduit of the first set of conduits 10 passes through the air heater 12. Advantageously, the thermal system 1 comprises a means 121 for adjusting a temperature T1 desired in the passenger compartment by a user of the motor vehicle 100. Advantageously, the temperature T1 corresponds to an overall temperature of the passenger compartment, that is to say an average temperature of the air in the passenger compartment.

[0025] In addition, the desired temperature T1 in the passenger compartment could be automatically set to a default value, when no user has defined a desired temperature.

[0026] The first heat transfer fluid of the thermal system 1 is directed towards the air heater 12, causing heating of air located near the at least one conduit passing through the air heater 12. Advantageously, this heated air will then be projected, in particular under the action of a ventilation system, towards different air vents arranged in the passenger compartment 2. In other words, the heat generated by the thermal system 1 is transmitted to the passenger compartment 2 via air passing through the air heater 12, near the first heat transfer fluid of the thermal system 1.

[0027] A temperature sensor 16 is advantageously arranged on the first set of conduits 10, making it possible to measure the temperature of the first heat transfer fluid. In a preferred embodiment, the sensor 16 is arranged so as to measure a temperature T3 of a heat transfer fluid circulating at the inlet of the air heater 12.

[0028] The thermal system 1 further comprises a heat pump 11, also called “heat pump system” in the remainder of the document, comprising a second set of conduits 110, the second set of conduits implementing a circulation of a second heat transfer fluid, also called “refrigerant fluid” in the remainder of the document.

[0029] The first heat transfer fluid circulating in the first set of conduits 10 of the thermal system 1 is itself heated by the second heat transfer fluid circulating in the second set of conduits 110 of the heat pump 11 via an exchanger called a condenser 111. The heat pump is said to be indirect because the condenser 111 is not placed directly in the air flow of the passenger compartment.

[0030] The first heat transfer fluid may be, for example, water, in particular glycolated water.

[0031] In an advantageous embodiment, the second heat transfer fluid is a fluid refrigerant, for example type R1234yf, R 134a, R290, R744 or any other fluid allowing the operation of a heat pump

[0032] In one embodiment, the second set of conduits 110 of the heat pump 11 creates a loop circulation of the second heat transfer fluid, successively connecting - the exchanger operating as a condenser 111, ensuring the transfer of heat from the second heat transfer fluid to the first heat transfer fluid, - a 112 regulator, - an exchanger operating as an evaporator 113, ensuring the transfer of heat from outside air or any other heat source, to the second heat transfer fluid, - a compressor 114, responsible for circulating and compressing the second heat transfer fluid in gaseous form.

[0033] In the embodiment described, an electric heating element 13 is arranged on the first set of conduits, or close to the first set of conduits. In addition, the conduits of the first set 10 are arranged so as to allow circulation of the first heat transfer fluid in a loop of conduits successively connecting the pump 16, the electric heating element 13, the condenser 111 and then the air heater 12.

[0034] In one embodiment, the electric heating element 13 is a ceramic resistor known as a positive temperature coefficient (PTC) resistor.

[0035] The system further comprises a supervisor 14 which coordinates the operation of the heat pump 11 (in particular via an adjustment of the power of the condenser 111) and the operation of the electric heating element 13.

[0036] In an advantageous embodiment, the thermal system 1, and more specifically the supervisor 14, further comprises the means for implementing a thermal management method according to the invention. In particular, the supervisor 14 comprises a processing unit 80 comprising a microprocessor 81, a memory 82 and communication interfaces 83.

[0037] The thermal system 1 and particularly the microprocessor 81, mainly comprises the following modules which cooperate with each other: - a module 811 for receiving a first desired temperature in a passenger compartment of the motor vehicle, this module being able to cooperate with the adjustment means 121 arranged on the air heater 12, - a module 812 for determining a second current temperature of the passenger compartment of the motor vehicle, this module being able to cooperate with a temperature sensor 21 arranged in the passenger compartment 2, or a temperature sensor 16 arranged at an entry point of the heat transfer fluid into the air heater 12, - a module 813 for transmitting a first temperature setpoint to the condenser temperature of the first heat transfer fluid, and transmission to the electric heating element of a second temperature setpoint of the first heat transfer fluid, this module being able to cooperate with the condenser 111 and the electric heating element 13, and - a module 814 for applying the first temperature setpoint C1 by the condenser 111 and for applying the second temperature setpoint C2 by the electric heating element 13, this module cooperating with the condenser 111 and the electric heating element 13.

[0038] The motor vehicle 100, in particular the thermal system 1, preferably comprises all the hardware and / or software elements configured so as to implement the method defined in the subject of the invention or the method described below.

[0039] With reference to [Fig. 2], a thermal management method is described comprising an iteration over four steps E1 to E4 which are executed successively. In one embodiment, the iteration over the four steps E1 to E4 is carried out every second, or every two seconds, or even every five seconds.

[0040] The thermal management method notably comprises: - a first step El of receiving a first desired temperature Tl in a passenger compartment 2 of the motor vehicle 100, - a second step E2 of determining a second current temperature (T2) of the passenger compartment (2) of the motor vehicle (100), - a third step E3 of transmitting to the heat pump 11 a first temperature setpoint C1 of the first heat transfer fluid and transmitting to the electric heating element 13 a second temperature setpoint C2 of the first heat transfer fluid, the first and second setpoints being calculated as a function of the first temperature T1 and the second temperature T2, and - a fourth step E4 comprising a sub-step E41 of application of the first temperature setpoint C1 by the heat pump 11 (via the condenser 111) and a sub-step E42 of application of the second temperature setpoint C2 by the electric heating element 13.

[0041] In the first step E1, a first temperature setpoint T1 is received corresponding to a desired temperature of air in the passenger compartment 2. In one embodiment, the temperature T1 may come from an adjustment means 121 of an air conditioning control arranged in the passenger compartment allowing a user of the motor vehicle 100 to adjust the temperature that he wishes in the passenger compartment 2. Alternatively, the temperature T1 may come from a system managing the personalization of the settings of the motor vehicle according to the preferences of a current user.

[0042] In the second step E2, a second current temperature T2 of the passenger compartment 2 of the motor vehicle 100 is determined. In one embodiment, a sensor temperature 21 can be arranged in the passenger compartment 2 to determine the second temperature T2. In one embodiment, the temperature T2 is a temperature of air blown into the passenger compartment 2.

[0043] Alternatively, the determination of the second temperature T2 can be carried out as a function of a third temperature T3 of a heat transfer fluid circulating at the inlet of the air heater 12, the temperature T3 being measured by a first temperature sensor 15 arranged at an inlet point of the heat transfer fluid into the air heater 12.

[0044] In addition or alternatively, the determination of the second temperature T2 can take into account a fourth temperature T4 of air circulating at the inlet of the air heater 12, the fourth temperature T4 being measured by a second temperature sensor 16.

[0045] In addition or alternatively, the determination of the second temperature T2 can take into account an air flow circulating in the air heater 12.

[0046] Advantageously, the determination of the second temperature T2 can take into account a model 132 of thermal characteristics of the air heater 12. Indeed, the temperature T2 can be calculated as a function of the air flow rate, the flow rate and the temperature of the first heat transfer fluid which passes through it and an abacus (a map) representing the efficiency curve of the air heater 12.

[0047] The thermal management method then comprises a third step E3, which comprises: - a transmission of a first temperature setpoint Cl to the condenser 111, and - a transmission of a second temperature setpoint C2 to the electric heating element 13, the first and second setpoints Cl, C2 being calculated as a function of the first temperature Tl and the second temperature T2.

[0048] Furthermore, a difference between the first setpoint C1 and the second setpoint C2 is strictly positive, in particular strictly greater than one degree, or even strictly greater than two degrees, or even strictly greater than three degrees. In one embodiment, the difference between the first setpoint C1 and the second setpoint C2 is equal to a constant positive threshold SI, the threshold SI being for example equal to 3 degrees.

[0049] Thus, in a preferred embodiment, the first setpoint Cl is determined as a function of the first temperature T1 and the second temperature T2.

[0050] In particular, the first setpoint Cl is calculated, corresponding to the temperature to which the first heat transfer fluid should be brought to cancel out the difference calculated between the first and second temperatures.

[0051] Advantageously, the determination of the first setpoint C1 comprises an implementation of a proportional, integral, derivative type regulator, called PID regulator in the remainder of the document.

[0052] In a preferred embodiment, the calculation of the second setpoint C2, intended for the electric heating element 13, is carried out by applying a reduction (or offset) of value SI to the first setpoint Cl, the value SI being strictly positive. In other words, the setpoint C2 is equal to the difference between the setpoint Cl and the offset SI.

[0053] In one embodiment, the offset SI may be equal to at least one degree Celsius, for example equal to one or two or three degrees Celsius.

[0054] In an embodiment more particularly illustrated by Figures 4 and 5, the value of the offset SI is constant, for example equal to three degrees. Thus, in the third step, a first setpoint C1 is determined to be transmitted to the condenser 111 of the heat pump 11, and a second setpoint C2 is calculated to be transmitted to the electric heating element 13, the setpoint C2 being equal to the setpoint C1 minus 3 degrees Celsius.

[0055] In certain situations, the power of the heat pump is not sufficient to heat the passenger compartment in steady state to the temperature T1 desired by a user (see the case illustrated by [Fig. 5], between times 206 and 207). In this case, the electric heating element 13 may be able to provide the additional heat necessary for the passenger compartment to reach and maintain the temperature T1. However, the setpoint C2 transmitted to the electric heating element 13 is calculated to be S1 degrees lower than the temperature actually required to reach the temperature T1 in the passenger compartment. Advantageously, when this situation occurs, in step E3, a maintenance of the current temperature of the passenger compartment T2 below the temperature T1 required by the user is detected.In this case, the temperature Tl is increased by a given number of degrees in order to allow the electric heating element 13 to provide more heat, so as to implement the temperature Tl in the passenger compartment 2.

[0056] The thermal management method then comprises a fourth step E4, which comprises: - a sub-step E41 of application of the first instruction Cl by the compressor 111, and - a sub-step E42 of application of the second instruction C2 by the electric heating element 13, the first and second sub-steps 41, 42 being able to be executed simultaneously.

[0057] In the first sub-step E41, upon receipt of the instruction C1, the supervisor 14 determines the quantity of heat to be transmitted by the condenser 111. To this end, the supervisor 14 can then implement a PID regulator in order to calculate a flow rate of the second heat transfer fluid circulating in the condenser 111, the flow rate being calculated so as to cancel - either a temperature difference between the first setpoint Cl and the current passenger compartment temperature T2 calculated or measured, - either a temperature difference between the first setpoint Cl and a fifth temperature T5 corresponding to the current temperature of the first heat transfer fluid circulating near the condenser 111. The PI power of the condenser is then adapted to implement the flow rate of the second heat transfer fluid calculated by the PID regulator.

[0058] In parallel, as illustrated by [Fig.3], in the second sub-step E42, upon receipt of the setpoint C2, the electric heating element 13 or the supervisor 14 can also implement a PID regulator in order to calculate an electric power P2 necessary to cancel - either a temperature difference between the second setpoint C2 and the current passenger compartment temperature T2 calculated or measured, - or a temperature difference between the second setpoint C2 and a sixth temperature T6 corresponding to the current temperature of the first heat transfer fluid circulating at the inlet of the electric heating element 13. The electric heating element 13 then applies the power P2 calculated by the PID regulator.

[0059] A new iteration of the previously described method can then be executed.

[0060] [Fig.4] illustrates an implementation of the invention when the temperature of an air outside the vehicle is equal to 0 degrees Celsius.

[0061] The abscissa axis 41 represents time. The ordinate axis 42 represents different quantities according to the curve: - curve Cl represents the temporal evolution of a temperature setpoint of the first heat transfer fluid, the setpoint Cl being transmitted by the supervisor 14 to the condenser 111, - curve T3 represents the temporal evolution of a measured or calculated temperature of a heat transfer fluid circulating at the inlet of the air heater 12, - the PI curve represents the temporal evolution of a power implemented by the condenser 111 to cancel the difference between the setpoint Cl and the temperature T3, and - curve P2 represents the temporal evolution of a power implemented by the electric heating element 13 to cancel a difference between a setpoint C2 and the temperature T3, the setpoint C2 (not shown on the graph) being equal to the setpoint Cl minus 3 degrees Celsius.

[0062] At the initial instant 101, the curve T3 shows that the temperature of the heat transfer fluid circulating at the inlet of the air heater is equal to 0°C.

[0063] In addition, at the initial time 101, from a required temperature in the passenger compartment, a setpoint Cl for the temperature of the heat transfer fluid is determined for the condenser. equal to 60°C.

[0064] In the scenario illustrated by [Fig.4], the user modifies the desired temperature in the passenger compartment, which notably leads to variations in the setpoint Cl. We thus observe that the setpoint Cl gradually decreases until a time 106 where it reaches 37°C. The setpoint Cl then stabilizes at 37°C until a time 107. Then between time 107 and a time 109, the setpoint Cl is maintained at a constant value of 50°C. Then beyond time 109, the setpoint Cl returns to 37°C.

[0065] We then compare the temporal evolution of the setpoint C1 and the temperature T3, and the impact of this evolution on the operation of the condenser 111 and the electric heating element 13.

[0066] Between times 101 and 102, the temperature T3 is much lower than the setpoint C1, the condenser 111 and the electric heating element 13 are therefore both started. The power deployed by the electric heating element 13 increases very quickly, while the power deployed by the condenser 111 is lower. Thanks to the power supplied by the electric heating element 13, at time 102, the temperature T3 is higher than the set temperature CL. A little before time 102, the power of the electric heating element 13 begins to decrease, until it becomes zero at time 105. It is also noted that a difference between the set point Cl and the temperature T3 is higher than 3°C (i.e. at the threshold SI) between times 103 and 104, which is correlated with a temporary increase in the power used by the electric heating element 13.

[0067] Between times 104 and 105, the curves PI and P2 intersect. This crossing materializes the increase in power of the compressor 111, the contribution of which becomes the majority in the thermal management of the motor vehicle 100.

[0068] Between times 105 and 107, the difference between the setpoint C1 and the temperature T3 is less than the threshold S1 (equal here to 3°C), therefore the setpoint C2 is less than the temperature T3. The electric heating element 13 is therefore stopped.

[0069] Then, between times 107 and 108, when the setpoint Cl suddenly increases from 37°C to 50°C, the difference between the setpoint Cl and the temperature T3 is again greater than the threshold SI; the electric heating element 13 is therefore restarted and operates until a time 108 when the difference between the setpoint Cl and the temperature T3 is again less than the threshold SL.

[0070] Thus, in the example illustrated by [Fig.4], the use of the electric heating element is relatively restricted, since it is reserved for transient periods of high temperature rise of the heat transfer fluid. Most of the time, the use of the heat pump 11 is sufficient to implement a temperature desired in the passenger compartment 2 by the user of the vehicle.

[0071] [Fig.5] represents the same curves as [Fig.4], in a situation where the tem- outside air temperature is -15°C.

[0072] At the initial time 201, the curve T3 shows that the temperature of the heat transfer fluid circulating at the inlet of the air heater is equal to 0°C.

[0073] Furthermore, at the initial time 201; a required temperature in the passenger compartment determines for the condenser a setpoint Cl of temperature of the heat transfer fluid equal to 60°C.

[0074] In the scenario illustrated by [Fig.5], the user modifies the desired temperature in the passenger compartment, which notably leads to variations in the setpoint Cl. We thus observe that the setpoint Cl gradually decreases until a time 205 where it reaches 37°C. The setpoint Cl then stabilizes at 37°C until a time 206. Then between time 206 and a time 207, the setpoint Cl is maintained at a constant value of 50°C. Then beyond time 207, the setpoint Cl returns to 37°C.

[0075] Between the starting times 201 and 202, the temperature T3 is much lower than the setpoint C1, the condenser 111 and the electric heating element 13 are therefore both started.

[0076] Between times 203 the difference between the setpoint C1 and the temperature T3 is less than the threshold S1 (equal here to 3°C), therefore the setpoint C2 is less than the temperature T3. The electric heating element 13 is therefore stopped, which is particularly visible on the curve P2, between times 204 and 206.

[0077] Nevertheless, between times 203 to 204, it is observed that the stopping of the electric heating element 13 is correlated with a strong increase in power of the condenser 111, until reaching its power limit at 8000 revolutions per minute.

[0078] In particular, between times 206 and 207, when the setpoint Cl is increased from 37°C to 60°C, the condenser cannot absorb this increase in power alone. The electric heating element 13 then remains activated between times 206 and 207, then stops when the setpoint Cl has dropped back to 37°C.

[0079] Finally, the invention firstly makes it possible to resolve the difficulties induced by the interdependence between the control of the condenser and the control of the electric heating element. In particular, thanks to the invention, acoustic discomfort and temperature fluctuations in the passenger compartment of the vehicle are eliminated.

[0080] Furthermore, the invention makes it possible to optimize the thermal management of the vehicle, in particular with respect to the heating of the passenger compartment, and this depending on the exterior temperature constraints.

[0081] The offset applied to the temperature setpoint transmitted by the electric heating element 13 allows - to use the electric heating element as a power supply when the temperature measurement in the passenger compartment gives a value much colder than the passenger compartment temperature desired by a user, - and to cancel this power input when the temperature measured in the passenger compartment is close to the desired setting.

[0082] Thus, the electric heating element 13 is used essentially to support the heat pump during temperature increase phases. Then, when the temperature of the passenger compartment is close to the temperature desired by the user, only the heat pump operates. In other words, the thermal system makes it possible both to quickly reach the desired passenger compartment temperature, and to preferentially use the heating system with the best thermal efficiency.

[0083] Furthermore, the maximum power available in a heat pump decreases with the ambient temperature. In particular, when the outside air temperature is below -10°C, the power of a heat pump is insufficient, and additional heating is necessary. The contribution of the electric heating element is then very appreciable, particularly when the vehicle has remained in a cold environment for a long time. The thermal management system according to the invention makes it possible to use an electric heating element in parallel with the heat pump system, while giving priority to the heat pump system in order to optimize the energy consumption of the vehicle.

[0084] Thus, the thermal management system according to the invention makes it possible to increase the autonomy of an electric vehicle.

Claims

Claims

1. Method for thermal management of a motor vehicle (100) equipped with - an electric heating element (13), - an air heater (12), - a heat pump (11) comprising a condenser (111), - and a first set (10) of conduits arranged so as to allow circulation of a first heat transfer fluid in a loop of conduits successively connecting the electric heating element (13), the condenser (111) then the air heater (12), characterized in that it comprises an iteration over four steps (E1, E2, E3, E4) which are executed successively: • a first step (El) of receiving a first desired temperature (Tl) in a passenger compartment (2) of the motor vehicle (100), • a second step (E2) of determining a second current temperature (T2) of the passenger compartment (2) of the motor vehicle (100), • a third step (E3) of transmitting to the heat pump (11) a first temperature setpoint (Cl) of the first heat transfer fluid and transmitting to the electric heating element (13) a second temperature setpoint (C2) of the first heat transfer fluid, the first and second setpoints being calculated as a function of the first temperature (Tl) and the second temperature (T2), a difference between the first setpoint (Cl) and the second setpoint (C2) being strictly positive, in particular strictly greater than one degree Celsius, or even strictly greater than two degrees Celsius, or even strictly greater than three degrees Celsius, the heat pump (11) comprising a second set (20) of conduits arranged so as to allow circulation of a second heat transfer fluid in the condenser (111), the method comprising a fourth step (E4) of calculating a flow rate (D2) of the second heat transfer fluid in the condenser (111), comprising: - a calculation of a second difference between the first temperature setpoint (Cl) of the first heat transfer fluid and a current temperature of the first heat transfer fluid, then - an implementation of a proportional, integral, derivative type regulator determining a flow rate setpoint (D2) of the second heat transfer fluid canceling the second difference.

2. Thermal management method according to the preceding claim, characterized in that the difference between the first setpoint and the second setpoint is equal to a constant positive threshold (SI), for example 3 degrees Celsius.

3. Thermal management method according to one of the preceding claims, characterized in that the second step (E2) comprises a determination of the second temperature (T2) - as a function of a third temperature (T3) of a heat transfer fluid circulating at the inlet of the air heater (12) measured by a first temperature sensor (15), and / or - as a function of a fourth temperature (T4) of air circulating at the inlet of the air heater (12) measured by a second temperature sensor (16), and / or - as a function of a flow rate (Dl) of air passing through the air heater (12), and / or - as a function of thermal characteristics of the air heater (12).

4. Thermal management method according to one of the preceding claims, characterized in that the calculation of the first temperature setpoint (Cl) of the first heat transfer fluid comprises: - a calculation of a first difference between the first temperature (Tl) and the second temperature (T2), then - an implementation of a proportional, integral, derivative type regulator, determining a first temperature setpoint (Cl) of the first heat transfer fluid canceling the first difference.

5. Thermal management method according to one of the preceding claims, characterized in that the fourth step (E4) further comprises a calculation of an electrical power necessary to cancel a temperature difference between the second setpoint (C2) and a current temperature of the first heat transfer fluid, comprising - a calculation of a third difference between the second setpoint (C2) of temperature of the first heat transfer fluid and a current temperature of the first heat transfer fluid, then - an implementation of a proportional, integral type regulator, derivative determining a power setpoint (P2) of the electric heating element canceling the third deviation.

6. Thermal management system (1) comprising hardware and / or software elements (1, 2, 10, 11, 12, 13, 14, 15, 16, 21, 80, 81, 82, 83, 110, 111, 112, 113, 114, 121, 811, 812, 813, 814) implementing the method according to one of claims 1 to 5.

7. Thermal management system (1) according to the preceding claim, characterized in that the electric heating element (13) is a ceramic resistor known as a positive temperature coefficient resistor.

8. Motor vehicle (100) equipped with a thermal system (1) according to one of claims 6 or 7.

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