A method for derating a target value of a temperature of a heat transfer liquid entering a cabin heater

Abstract

Method for managing a derating of a thermal power transferred to a cabin of a vehicle with an electric powertrain, in case of a full exploitation of the available thermal power, without resorting to the use of a double electric heater, one for the heat transfer liquid entering a cabin heater (CAB) in a heat exchange relationship with the cabin, and one for the heat transfer liquid which enters a heating circuit of a high-voltage battery (BAT), so that it is possible to maintain the use of a single electric heater (ECH).

Description

[0001] "A method for derating a target value of a temperature of a heat transfer liquid entering a cabin heater"

[0002] ★★★★

[0003] TEXT OF THE DESCRIPTION

[0004] Field of the Invention

[0005] The present invention refers to thermal conditioning circuits, specifically operating with a heat transfer liquid. The invention was developed with particular reference to a thermal conditioning system operating with a heat transfer liquid, which is in a heat exchange relationship with a cabin and a high- voltage battery of a vehicle with an electric powertrain for heating either or both elements.

[0006] Prior art

[0007] The vehicles with an electric powertrain, particularly BEVs, require, as it is commonly known, a thermal conditioning system for the high-voltage battery, which supplies one or more electric traction motors, in addition to the traditional thermal conditioning system for the cabin. As is commonly known, moreover, said thermal conditioning systems operate both for cooling the cabin and the high-voltage battery and for heating the cabin and the high-voltage battery.

[0008] The functions of cooling and heating are implemented, respectively, by means of an interaction with a refrigeration cycle cooling circuit, traversed by a refrigerant fluid which undergoes phase changes from liquid to gas and from gas to liquid, and by means of direct heat exchange between the heat transfer liquid and the spaces or the components to be heated.

[0009] A known configuration of a circuit for heating the cabin and the high-voltage battery comprises the provision of two separate circuits, each comprising a heat exchange device, an electric heater (so-called "ECH", Electric Coolant Heater) upstream of the heat exchange device, and a circulation pump. In the case of heating a cabin of the vehicle, the heat exchange device is a cabin heater arranged downstream of a cabin evaporator and impinged upon by a flow rate of air coming from the same cabin evaporator in a variable amount, according to the position of a blending flap. In the case of heating the high-voltage battery, the heat exchange device comprises a circuit portion wherein the heat transfer liquid impinges upon thermally conductive surfaces being in a heat exchange relationship with the elements of the battery.

[0010] Each electric heater is activated to rapidly raise the temperature of the heat transfer liquid which flows in the respective heating circuit, in such a way as to achieve the targets of thermal comfort in the cabin and of operative temperature of the high-voltage battery.

[0011] Such a solution, however, proves to be very disadvantageous as regard its cost, since an electric heater is required for each heat exchange device: the control must be doubled, and the absorption (and less than optimal use) of electric power is twice as much.

[0012] In this regard, the Applicant has proposed a solution of a circuit for heating the cabin and the battery of the powertrain of the vehicle with a single electric heater arranged upstream of the cabin heater, and having spill valves to direct part of the flow rate from the heating circuit of the cabin to the heating circuit of the battery, and vice versa. Said solution is disclosed in the Italian Industrial Invention Application n. 102024000009115.

[0013] In said solution of heating circuit, the absence of an electric heater for each heating (sub)-circuit, i.e. the fact of having only one electric heater, leads to a less flexible configuration in case of a need to derate the thermal power transferred to the cabin, i.e. in case of a complete exploitation of the power available for heating and a simultaneous need to favour the heating of the battery. In comparison to this, in a circuit with two electric heaters, the former being associated with the cabin heater and the latter being associated with the battery of the powertrain, such a requirement could be satisfied by simply supplying only the electric heater associated with the battery. However, the additional costs and complexity deriving from a configuration with two heaters are such that they anyway annul any advantage connected with such a simplification.

[0014] Object of the Invention

[0015] The invention aims at solving the technical problems mentioned in the foregoing. Specifically, the object of the present invention consists in providing a method for handling the derating of the thermal power transferred to the cabin of the vehicle in case of a full exploitation of the available thermal power, without resorting to the use of two electric heaters (the former for the heat transfer liquid entering the cabin heater, the latter for the heat transfer liquid entering the heating circuit of the battery), i.e. maintaining the use of a single electric heater for all the heat exchange devices of the circuit (cabin heater and battery heating circuit).

[0016] Summary of the Invention

[0017] The object of the invention is achieved by means of a method having the features set forth in the claims that follow, which form an integral part of the technical disclosure provided herein in relation to the invention.

[0018] Brief Description of the Figures

[0019] The invention will now be described with reference to the annexed Figures, which are provided by way of non-limiting example only, and wherein:

[0020] - Figure 1 shows a thermal conditioning circuit wherein it is possible to implement a method according to the invention,

[0021] - Figure 2 shows a flow diagram representative of the method according to the invention, while Figures 3 and 4 show respective block diagrams similarly representative of the method according to the invention,

[0022] - Figures 5 to 7 respectively show exemplifying diagrams of determinations operated in the execution of the method according to the invention, and

[0023] - Figures 8 and 9 show implementations of the method according to the invention in the control of a thermal conditioning circuit.

[0024] Detailed Description

[0025] Reference C in Figure 1 globally denotes a thermal conditioning circuit, specifically a heating circuit for a vehicle with an electric powertrain, which is used as an example for the description of the implementation of the method according to the invention.

[0026] The circuit C includes:

[0027] - a first heat exchange device CAB, which in the specific example illustrated herein is a cabin heater for heating a flow rate of cabin air mCab Airsupplied to a cabin of the vehicle (the cabin heater CAB is therefore in heat exchange relationship with the flow rate of cabin air mCab Air), traversed by a first flow rate of heat transfer liquid mCabin a first flow direction Fl,

[0028] - an electric heater ECH arranged upstream of the first heat exchange device CAB with respect to the first flow direction Fl of the heat transfer liquid,

[0029] - a first circulation pump CPI having a delivery port arranged upstream the electric heater ECH with respect to the first flow direction Fl of the heat transfer liquid. The first circulation pump CPI supplies the first flow rate mCabto the electric heater ECH and to the first heat exchange device (CAB), - a first recirculation branch R1 that connects an outlet of the first heat exchange device CAB with a suction port of the first circulation pump CPI,

[0030] - a second heat exchange device BAT, which in the specific example illustrated herein is a battery heater for heating a battery of the powertrain of the vehicle (specifically a high-voltage battery for supplying one or more electric traction motors - the battery heater BAT is therefore in a heat exchange relationship with the battery of the powertrain of the vehicle), traversed by a second flow rate of heat transfer liquid mBatin a second flow direction F2,

[0031] - a second recirculation pump CP2 having a delivery port arranged upstream of the second heat exchange device BAT with respect to the second flow direction F2 of the heat transfer liquid. The second circulation pump supplies the second flow rate mBatto the second heat exchange device BAT,

[0032] - a second recirculation branch R2 that connects an outlet of the second heat exchange device BAT with a suction port of the second circulation pump CP2,

[0033] - a first branch Bl, configured for a transit of a spill flow rate from the first recirculation branch

[0034] R1 to the second recirculation branch R2, wherein a first spill valve VI is arranged upstream of the first branch Bl to regulate the transit of the spill flow rate from said first recirculation branch R1 to said second recirculation branch R2, (the phrase "regulate the transit of the spill flow rate ThSpnt" indicates the fact the valve VI is configured to deliver a flow rate to the branch R2 in an amount which is continuously variable - by varying a chocking degree of the same valve - between a null flow rate and a maximum flow rate allowable by the valve VI, which may be equal to 'rhCab),

[0035] - a second branch B2, configured for a transit of a spill flow rate rii-spiitfrom the first recirculation branch R2 to the first recirculation branch Rl, wherein a second spill valve V2 is arranged upstream of the second branch to regulate the transit of the spill flow rate from the second recirculation branch R2 to the first recirculation branch Rl (in the same way as in the foregoing, the phrase "regulate the transit of the spill flow rate riispitt" indicates the fact the valve V2 is configured to deliver a flow rate to the branch Rl in an amount which is continuously variable - by varying a chocking degree of the same valve - between a null flow rate and a maximum flow rate allowable by the valve VI, which may be equal to 'rhBat).

[0036] Always referring to Figure 1, the recirculation branch Rl and the recirculation branch R2 substantially define a return path of the heat transfer liquid towards the suction of the pumps CPI and CP2, respectively. At the valves VI and V2, the recirculation branches are put into fluid communication with each other through the branches Bl and B2, so that - in the presence of a spill flow rate m^p^ other than zero - the sections of the recirculation branches Rl, R2 downstream of the respective valve VI, V2 (such sections are denoted with RIA, R2A) are traversed by a flow rate of recirculation heat transfer liquid m-cabjucr m-BatjUc inanamount lower than the flow rates mCab, mBat, respectively. The section RIA extends between the valve VI and a first circuit node N1 downstream of the branch B2, whereas the section R2A extends between the valve V2 and a second circuit node N2 downstream of the branch Bl. The nodes N1 and N2 are nodes of confluence of the flow rate of the recirculation heat transfer liquid riicab_Ricr m-BatjUc (respectively) and the spill flow rate mSpiit.

[0037] As regards the valves VI and V2, they are preferably implemented as three-way, continuous positioning valves, in such a way as to bring about a regulation of the spill flow rate 'rhspiit described in the foregoing, with the following hydraulic connection arrangement:

[0038] - the valve VI comprises a first port connected downstream of the first heat exchange device, specifically a cabin heater, CAB, a second port connected upstream of the section RIA, and a third port connected upstream the branch Bl. The first and the second port are always in fluid communication, except when the spill flow rate coming from the branch R1 is equal to the flow rate mCab. This anyway guarantees the recirculation of the spill flow rate towards the suction of the pump CPI when the flow rate mCaj, is greater than the spill flow rate riispiitr whereas the third port is in fluid communication with the first port (and the second port) in a variable amount, as a function of the amount of the spill flow rate riispiitr and it is isolated, in turn isolating the recirculation branch R1 (and - globally - the circuit which comprises the heater ECH and the first device CAB) from the recirculation branch R2 only when the spill flow rate is null;

[0039] - the valve V2 comprises a first port connected downstream of the second heat exchange device, specifically the battery heater, BAT, a second port connected upstream of the section R2A and a third port connected upstream of the branch B2. The first and the second port are always in fluid communication, except when the spill flow rate coming from the branch R1 is equal to the flow rate mBat. This guarantees in any case the flow rate at the suction of the pump CP2, and guarantees the recirculation of the flow rate mBat(which may be total or reduced to the flow rate 'rnBat Ric') towards the suction of the pump CP2, when the flow rate mBatis greater than the spill flow rate rii-spiit• The third port is in fluid communication with the first port (and the second port) in an amount variable as a function of the amount of the spill flow rate riispiitr and it is isolated, in turn isolating the recirculation branch R1 (and - globally - the circuit which comprises the heater ECH and the first device CAB) from the recirculation branch R2 only when the flow rate is null or when the flow rate mBatis null. The fluid communication between the first and the third port of the valve V2 guarantees that, when the first and the second port of the valve VI are isolated (or anyway are not traversed by any flow rate), since mSpiit= mCab, the flow rate recirculation to the suction of the pump CPI is anyway ensured.

[0040] As a general rule, every reference to a "flow rate" in the present description shall be construed as a reference to a mass flow rate, as indicated by the notation m employed for all flow rates.

[0041] Again, as a general rule, any time the present description refers to a "battery" (also in phrases such as "battery heater"), this shall be construed as a high- voltage battery of the vehicle (specifically of the powertrain of the vehicle) which supplies one or more electric traction motors of the powertrain of the vehicle, unless (where) otherwise specified.

[0042] The circuit C moreover comprises a plurality of temperature sensors, comprising: a sensor TS_ECH_IN, configured to detect the temperature of the heat transfer liquid at the inlet of the heater ECH,

[0043] - a sensor TS_ECH_OUT, configured to detect the temperature of the heat transfer liquid at the outlet of the heater ECH (and therefore at the inlet of the first heat exchange device / cabin heater CAB), a sensor TS_AIR_IN, configured to detect the temperature of the flow rate of air mCab Airimpinging upon the first heat exchange device / cabin heater CAB at an inlet section thereof, a sensor TS_BAT_IN, configured to detect the temperature of the heat transfer liquid at the inlet of the second heat exchange device / heater BAT,

[0044] - a sensor TS_ECH_OUT, configured to detect the temperature of the heat transfer liquid at the outlet of the second heat exchange device / heater BAT.

[0045] With reference to the Figures 2, 4, and with the general premise that the description provided in the following refers to the preferred embodiment of the circuit C, wherein the first heat exchange device CAB is a cabin heater and the second heat exchange device BAT is a battery heater, but it can be referred to any thermal conditioning circuit having similar operation and requirements, the method according to the invention includes:

[0046] - determining (block 2, Figure 2 and block 22, Figure 4) a first derated target temperature value TcaH_in_Der_Drv_Tgt of the heat transfer liquid entering the first heat exchange device CAB under conditions other than vehicle charging, as a function of a nominal target temperature value TCaH In HVAC Tgtof the heat transfer liquid entering the first heat exchange device CAB, of an external ambient temperature Tamb, and preferably as a function of a current driving mode Drv_Mod,

[0047] - determining (block 4 and block 24, Figure 4) a second derated temperature target value TCaH In Der Chrg Tgtof the heat transfer liquid entering the first heat transfer device CAB under vehicle charging conditions, as a function of a charging power available to the battery PgattchrgAvii °f the nominal target temperature value TCaH In HVAC Tgtof the heat transfer liquid entering the first heat exchange device CAB, and of the external ambient temperature Tamb,

[0048] - adopting (block 6 and block 26, Figure 4) the first derated target temperature value TCaHInDerDrvTgt'^CaH InDerTgt=TCaHJn_Der_Drv_Tgt') if thevehicle is in conditions other than vehicle charging, (Charging_Active = 0) and if there are no requests for the thermal conditioning of the vehicle cabin (Special_Cabin_Conditioning_Active = 0) incompatible with adopting the first derated target temperature value, and controlling said thermal conditioning circuit (C) according to said first derated target temperature value

[0049] TcaHJn_Der_Drv_Tgt (TcaHJn_Der_Tgt—^CaH In DerDrvTgt!r

[0050] - adopting (block 6 and blocks 16, 26 in Figure 4) the second derated target temperature value ^CaH InDerChrgTgt '^CaH In DerTgt~ ^CaH InDerChrgTgt!if the vehicle is in charging conditions (Charging_Active = 1) and if there are no requests for the thermal conditioning of the vehicle cabin {Special_Cabin_Conditioning_Active = 0) incompatible with adopting said second derated target temperature value, and controlling said thermal conditioning circuit (C) according to said second derated target temperature value TCaH In Der Chrg Tgt

[0051] (TcaHJn_Der_Tgt ~ TcaH InDerChrgTgt)•

[0052] In the method according to the invention, under vehicle charging conditions an electric current enters the vehicle from the outside, specifically from a charging station, while in conditions other than charging there is no electric current entering the vehicle from the outside.

[0053] In other words, the phrase "vehicle charging" denotes a condition wherein the vehicle absorbs current from the outside, specifically from a charging station, and said current is used for charging the high-voltage battery and / or for supplying one or more electric users of the vehicle, possibly only for supplying the one or more electric users of the vehicle when the current is not supplied to the high-voltage battery. The feature which discriminates between the conditions of "vehicle charging" and "other than vehicle charging" is the input of an electric current coming from the outside, specifically coming from a charging station. This means that the connection of the vehicle to a charging station may not necessarily imply a condition of vehicle charging, particularly if no current transit takes place from the charging station to the vehicle (battery and / or electric users).

[0054] In the following, all the aspects of the method according to the invention will be described with reference to the Figures 3 to 7.

[0055] Figure 3, diagram 10, shows a block diagram representative of a layering of the control logics which act on the circuit C and which control the combined heating of the battery and of the cabin by means of the circuit C. In the circuit C, the heater ECH is arranged only in the circuit (or sub-circuit) portion dedicated to heating the cabin, therefore in the circuit C a migration of thermal heating power takes place from the sub-circuit dedicated to heating the cabin to the subcircuit dedicated to heating the battery. For this reason, the control of the thermal conditioning of the cabin - schematically shown in a block 12 (HVAC control) comprises a combination of three controls, specifically:

[0056] - a first control 14 which, based on the nominal target temperature value TCaH In HVAC Tgtof the heat transfer liquid entering the first heat exchange device / cabin heater CAB, defines a target value of thermal heating power that the heater ECH shall output to express at least the nominal target temperature value TcaH_in_HVAC_Tgt at the outlet thereof, operatively corresponding to the inlet of the cabin heater CAB. The control 14 is configured to control the heater ECH so that it outputs at least the nominal target temperature value TCaHjn_HVAC_Tgt because, in the case of a combined heating of the high-voltage battery and of the cabin, the higher value is selected between the target temperature value TCaH In HVAC Tgtof the heat transfer liquid at the inlet of the cabin heater CAB and the target temperature value of the heat transfer liquid at the inlet of the battery heater,

[0057] - a second control 16 which, based on the derated temperature target value TCaH In Der Tgtof the heat transfer liquid at the inlet of the first heat exchange device / cabin heater CAB (which may be equal to TCaHInDerDrvTgt, TcaHjn_Der_chrgTgt> or to TCaH In HVAC Tgtif there are requests for conditioning the cabin of the vehicle (Special_Cabin_Conditioning_Active = 1) which are incompatible with adopting the values TCaH In Der Drv Tgt, TCaH In Der chrg Tgt), defines a thermal power distribution between the circuit sections dedicated to heating the cabin and to heating the battery, and a consequent target value of spill flow rate tTiSpiit Tgt;

[0058] - a third control 18 upstream of the control 16, and configured for determining a derated target value TcaH_in_Der_Tgt corresponding to adopting the first or the second derated target value TCaH In Der Drv Tgt, TCaH In Der chrg Tgt- as described in the foregoing - if the electric power available for heating (which is drawn from the high- voltage battery of the vehicle) is exploited to the full. In this regard, the arrangement of the control 18 upstream of the control 16 implies the adaptation of the value of the spill flow rate diSpiit Tgtto the derated target.

[0059] Figures 4 and 5, diagrams 20 and 30, generally and schematically show the method according to the invention. Referring to Figure 4, diagram 20, the block 22 is representative of determining the first derated target value TCaHInDerDrvTgt, i.e. a temperature value of the heat transfer liquid at the inlet of the heater CAB which is derated due to the full exploitation of the electric heating power under conditions other than the vehicle charging. As can be seen in the diagram of Figure 4, such determining is operated as a function of a current driving mode Drive_Mod (in the preferred embodiment, whereas in other embodiments and / or in embodiments implemented in vehicles which do not offer the option of driving mode selection, the determination does not take into account the current driving mode), of the nominal target temperature value TCaH In HVAC Tgtdetermined by the control 12, and of the temperature TAmbof the external environment. The block 24 of diagram 20, on the other hand, is representative of determining the second derated target value TCaH In Der chrg Tgt, i.e. a temperature value of the heat transfer liquid at the inlet of the heater CAB which is derated due to the full exploitation of the electric heating power under vehicle charging conditions, i.e. under conditions of connection of the vehicle to a charging station. As can be seen in the diagram of Figure 4, the determination is operated as a function of a charging power available to the battery PBatt_chrg_Avi (which depends on the characteristics of the charging station), of the nominal target temperature value TCaH In HVAC Tgtdetermined by the control 12 and of the temperature TAmbof the external environment.

[0060] The outputs of the blocks 22, 24, i.e. the derated target values TCaH In Der Drv Tgtand TCaH In Der chrg Tgt, are input into the block 26, which defines the (derated or nonderated) target value to be adopted for the temperature of the heat transfer liquid at the inlet of the first heat exchange device / cabin heater CAB as a function of the nominal target value TCaH In HVAC Tgt, as a function of the presence of one or more requests for conditioning the cabin of the vehicle which are incompatible with adopting the first or of the second derated target temperature value and as a function of the fact that the vehicle is under charging conditions. The first circumstance, i.e. the presence of one or more requests for conditioning the cabin which are incompatible with adopting the first or the second derated target temperature value TCaHInDerDrvTgt, TCaH In Der chrg Tgt, is represented by a variable Special_Cabin_Conditioning_Active, which acquires the logic state "0" (FALSE) when there are no requests incompatible with adopting the first or the second derated target temperature value ^caH inDerDrvTgti TCaH In Der Chrg Tgt, and the logic state "1" (TRUE) when there are requests which are incompatible with adopting the first or the second derated target temperature value TCaHInDerDrvTgt, TCaHInDerChrgTgt. An example of request of this type comprises a request for defrosting / defogging (so-called defrost mode) the windshield of the vehicle by means of the conditioning system whereof the heater CAB is part: indeed, this is a request which has a direct impact on the driving safety of the vehicle, since a clouded or frosted windshield impairs visibility.

[0061] Since this is a request which, if satisfied, would lead to a derating, i.e. a reduction, of the target temperature value of the heat transfer liquid entering the heater CAB, the method according to the invention - block 26 - envisages maintaining the nominal target temperature value TCaH In HVAC Tgtof the heat transfer liquid entering the first heat exchange device / cabin heater CAB if there is a request for conditioning the cabin of the vehicle (Special_Cabin_Conditioning_Active = 1) incompatible with adopting the first or the second derated target temperature value TCaHInDerDrvTgt, TcaH InDerChrgTgt• The second circumstance, i.e. the fact that the vehicle is under charging conditions, is represented by a further variable Charging_Active, which acquires the logic state "0" (False) when the vehicle is not under charging condition, and the logic state "1" (True) when the vehicle is under charging conditions. Unlike the variable Special_Cabin_Conditioning_Active, the logic state whereof determines - or does not determine - a precedence of the nominal target value TCaH In HVAC Tgtover the target values TCaHInDerDrvTgt, TCaHInDerChrgTgt, the logic state of the variable Charging_Active essentially determines the selection of one out of the first derated target value TcaH_in_Der_Drv_Tgt and the second derated target value TcaH [nDerChrgTgt•

[0062] Referring to Figure 5, diagram 30, it shows the interaction of the variables Special_Cabin_Conditioning_Active and Charging_Active with the determinations as per the method according to the invention.

[0063] In detail, a first switch 32 is configured to output a raw derated target value TCaH In Der Raw Tgtof the temperature of the of the heat transfer liquid entering the cabin heater (CAB), which may correspond to the first derated target value TCaH In Der Drv Tgtor to the second derated target value TCaH In Der chrg Tgtas a function of the logic state of the variable Charging_Active, which operates as a control variable for the switch 32. A block 34 defines a logical condition which acts as a discriminant for the determination of the output TCaH In Der Raw Tgtof the switch 32, in particular the fact that the logic state of the variable Charging_Active corresponds to "1" (True). In the affirmative, i.e. Charging_Active= 1, the output of the switch 32 corresponds to the condition shown in Figure 5, i.e. TCaH In Der Raw Tgt= TCaHInDerChrgTgt, the second derated target value corresponding to a condition of vehicle under charging conditions (which is consistent with the meaning of the variable Charging_Active).

[0064] In the negative, i.e. Charging_Active = 0 (False), the output of the switch 32 corresponds to the contrary condition with respect to the condition shown in Figure 5, therefore TCaH In Der Raw Tgt= TCaH In Der Drv Tgt, the first derated target value corresponding to a vehicle condition other than the vehicle charging condition.

[0065] The output TCaH In Der Raw Tgtof the switch 32 is input into a second switch 36, which is configured to output a (final) derated target value TCaHInDerTgtof the temperature of the heat transfer liquid entering the cabin heater (CAB), which may correspond to the raw derated target value TCaH In Der Raw Tgtoutput from switch 32, or to the nominal target temperature value TcaH inHVACTgttas afunction of the logic state of the variable Special_Cabin_Conditioning_Active, which operates as a control variable for the switch 36. A block 38 defines a logical condition which acts as a discriminant for determining the output TCaH In Der Tgtof the switch 36, specifically the fact that the logic state of the variable Special_Cabin_Cauditioning_Active corresponds to "1" (True). In the affirmative case, i.e. Special_Cabin_Conditioning_Active = 1, the output of the switch 36 corresponds to the condition shown in Figure 5, i.e. TcaHjn_Der_Tgt= TCaHjn_HVACTgtr the nominal target value determined by the control 12. As described in the foregoing, this derives from the meaning of the variable Special_Cabin_Conditioning_Active: if there are requests for thermal conditioning which are incompatible, basically because they have a priority over the derating, with adopting the first or the second derated value, the method according to the invention maintains the nominal target value TCaH In HVAC Tgt.

[0066] In the negative instance, i.e.

[0067] Special_Cabin_Conditioning_Active = 0 (False), the output of the switch 36 corresponds to the opposite condition with respect to the condition shown in Figure 5, thus TcaH_in_Der_Tgt=TCaH In Der Raw Tgt, and therefore to the first or the second derated target value corresponding to the determination by switch 32.

[0068] The following Figure 6, diagram 40, shows the determination of the first derated target temperature value TCaHInDerDrvTgtof the heat transfer liquid entering the cabin heater CAB under conditions other than charging.

[0069] In detail, this comprises determining the first derated target temperature value TCaH In Der Drv Tgtas the minimum (block 42, MIN - it defines an upper limit) between the nominal target temperature value TCaH In HVAC Tgtof the heat transfer liquid entering the cabin heater (CAB) and the greater value (block 44, it defines a lower limit) out of: i) a temperature value TCaH In Der DrVModTgt corresponding to a maximum temperature reduction of the heat transfer liquid entering the cabin heater under conditions other than vehicle charging, which depends on the temperature of the external environment TAmband on the current driving mode Drv_Mod, ii) a difference (block 46) between the nominal target temperature value TCaH In HVAC Tgtof the heat transfer liquid entering the cabin heater CAB and a value of temperature reduction of the heat transfer liquid entering the cabin heater CAB under conditions other than vehicle charging ATCaHInDerDrvModTgt, which depends on the temperature of the outer environment TAmband on the current driving mode Drv_Mod.

[0070] Operatively, the value TCaH In Der DrvMod Tgtis determined by means of a map M47 which uses, as input data, the temperature value TAmband the current driving mode Drv_Mod, and which outputs the value TcaHJnDerDrvModTgt•The maPM47shows four temperature curves TCaHlnDerDrvModTgtparameterized with respect to four different driving modes Drv_Mod_l, Drv_Mod_2, Drv_Mod_3, Drv_Mod_4, which are mentioned in an order of decreasing aggressiveness. On a qualitative level, the temperature value of the heat transfer liquid due to a condition other than vehicle charging TCaHlnDerDrvModTgtdecreases as the aggressiveness of the driving mode decreases (for example, with a maximally aggressive driving mode such as Drv_Mod_l it is important to heat the high-voltage battery as rapidly as possible, and therefore the difference of thermal heating power between the cabin (CAB) and the high-voltage battery (BAT) is greater), and it increases as the ambient temperature TAmbdecreases (for example, because with low external temperatures the thermal heating power required for the cabin increases).

[0071] In the same way, the value ^TCaHInDerDrvModTgtis determined by means of a map M48 which uses, as input data, the temperature value TAmband the current driving mode Drv_Mod, and outputs the value ATCaH In Der DrvModTgt• The map M48 shows four curves of temperature reduction ^TcaH in_Der_DrvMod_Tgtr parameterized with respect to four distinct driving modes Drv_Mod_l, Drv_Mod_2, Drv_Mod_3, Drv_Mod_4, mentioned in order of decreasing aggressiveness. On a qualitative level, the temperature reduction of the heat transfer liquid due to the driving mode of the vehicle &TCaH In Der DrvMod Tgtincreases as the aggressiveness of the driving mode increases (for example, with a maximally aggressive driving mode, such as Drv_Mod_l, it is important to heat the high-voltage battery as rapidly as possible, and therefore the difference of thermal heating power between the cabin (CAB) and the high-voltage battery (BAT) is greater), and it decreases as the ambient temperature TAmb decreases (in particular because with low external temperatures it is more convenient not to depart from the target value determined by the control 12).

[0072] Finally, the following Figure 7, diagram 50, shows the determination of the second derated target temperature value TCaH In Der Chrg Tgtof the heat transfer liquid entering the cabin heater CAB under conditions of vehicle charging.

[0073] In detail, this comprises determining the second derated target temperature value TCaH In Der chrg Tgtas the lower (block 52, MIN - it defines an upper limit) out of the nominal target temperature value TCaH In HVAC Tgtof the heat transfer liquid entering the cabin heater (CAB) and the greater value (block 54, MAX - it defines a lower limit) of: iii) a temperature value TCaH In Der chrg Tgtcorresponding to a maximum temperature reduction of the heat transfer liquid entering the cabin heater under vehicle charging conditions, which depends on the temperature of the external environment TAmband on the charging power available to the battery PBatt_chrg_Avir iv) a difference (block 56) between the nominal target temperature value TCaH In HVAC Tgtof the heat transfer liquid entering the cabin heater CAB and a value of a reduction in the temperature of the heat transfer liquid CAB under vehicle charging conditions ^TCaH In Der Chrg Tgt, which depends on the temperature of the external environment TAmband on the charging power available to the battery PBatt_chrg_Avi•

[0074] Operatively, the value TCaH In Der Chrg Tgtis determined by means of a map M57 which uses, as input data, the temperature value TAmband the current driving mode PBatt_chrg_Avi> and outputs the value TCaHIn DerChrg Tgt. The map M57 shows four temperature curves TCaH In Der Chrg Tgtparameterized with respect to four levels of available charging power PBatt_Chrg_Avl_l, PBatt_Chrg_Avl_2,

[0075] PBatt_Chrg_Avl_3, PBatt_Chrg_Avl_4, mentioned in order of decreasing power. On a qualitative level, the temperature value of the heat transfer liquid due to vehicle charging TCaH In Der chrg Tgtdecreases as the charging power increases (for example with a mode of high charging power, thus for a very rapid battery charging, it is important to heat the high-voltage battery as rapidly as possible, and therefore the difference between the thermal heating power of the cabin (CAB) and of the battery (BAT) is greater), and it increases as the ambient temperature TAmbdecreases (for example, because with low external temperatures there is an increase of the thermal heating power required for the cabin).

[0076] In the same way, the value ATCaH In Der chrg Tgtis determined by means of a map M58 which uses, as input data, the temperature value TAmband the charging power available to the battery Pgattchrg Avi / and outputs the value ATCaH ln Der DrvMod Tgt. The map M48 shows four curves of temperature reduction ^TCaHInDerDrvModTgtparameterized with respect to four levels of available charging power PBatt_Chrg_Avl_l, PBatt_Chrg_Avl_2, PBatt_Chrg_Avl_3,

[0077] PBatt_Chrg_Avl_4, mentioned in an order of decreasing power. On a qualitative level, the temperature reduction of the heat transfer liquid due to the vehicle charging ^TcaH in_Der_chrg_Tgt increases as the available charging power increases (again, with a greater availability of charging power it is important to heat the high-voltage battery as rapidly as possible, and therefore the difference of thermal heating power between the cabin (CAB) and the high-voltage battery (BAT) is greater), and it decreases as the ambient temperature TAmbdecreases (in particular because, with low external temperatures, it is more convenient not to depart from the target value as determined by the control 12).

[0078] Once the derated values TCaH In Der Drv Tgt,

[0079] TcaH_in_Der_chrg_Tgt are known, the circuit C is controlled as generally disclosed in the Italian Patent Application for Industrial Invention n. 102024000009115, with the addition of the actions schematically shown in Figure 3 only as regards the determination of the spill flow rate m-spiitTgt (controls 16 and 18).

[0080] Operatively, in the circuit C the heater ECH is controlled as generally disclosed in the Italian Patent Application for Industrial Invention n. 102024000009115, thus by determining a target thermal power value QECH Tgt which the electric heater ECH shall output in order to satisfy a target temperature value TECH Out Tgtof the heat transfer liquid leaving the heater, which is determined as a function of target temperature values TCab ctnt In Tgt(heat transfer liquid entering the first heat exchange device / cabin heater CAB - which corresponds to the nominal target value TCaH In HVAC Tgt) and TBat clntJn Tgt(heat transfer liquid entering the battery heater BAT) and of a target value mCab Tgtof the first flow rate mCaband a target value mBat Tgtof the second flow rate mBat, the flow rate values whereof are connected to the temperature targets TCab clnt In Tgtand TBat clnt In Tgt. This means, as can be seen in Figure 3, that the control of the heater ECH does not take into account the derating of the target temperature value of the heat transfer liquid entering the cabin heater CAB but, on the contrary, the heater ECH is controlled only as a function of nominal target temperature values which are not subjected to derating.

[0081] The intervention of the derated target temperature value TCaH In Der Drv Tgtor^CaH In DerChrgTgt Consists in controlling the valves VI and V2 for defining the flow rate ThSpiit Tgt: the latter is determined as a function of the derated target value TCaH In Der Drv Tgtor TCaH In Der Chrg Tgt and not as a function of the nominal target value TcabcintinTgt• The reason is as follows: in conditions of full exploitation of the thermal (i.e., electric) power available for the combined heating of the cabin and of the battery, the method according to the invention attempts to find a compromise between the heating requirements of the battery and those of the cabin, by mitigating the redistribution of thermal power in favour of the high-voltage battery (which is a component which absorbs much more thermal power than the cabin; therefore, the greater thermal power redirected towards the battery, the greater the absorption of said electric power by the battery) in such a way as not to excessively jeopardize the cabin heating. In this regard, the derated target temperature value TCaH In Der Drv Tgtor TCaH In Der chrg Tgtshall be construed both as a reduction of the performance pressure on the first heat exchange device / cabin heater CAB, and as a lower temperature limit for the requirements of the cabin heating, in such a way as to avoid situations - which are common in known solutions - wherein the thermal power is totally delivery to the battery only.

[0082] In more detail, referring again to the Italian Patent Application for Industrial Invention n. 102024000009115, controlling the thermal conditioning circuit (C) as a function of the first or of the second derated target temperature value (whichever is selected) comprises:

[0083] - determining a target value Tgt of the first flow rate mCaband a target value mBat Tgtof the second flow rate frtBatas afunction, respectively, of the nominal target value TCaH In HVAC Tgtof the temperature of the heat transfer liquid entering the first heat exchange device / cabin heater CAB and of a further target value TBat_cint_in_Tgt of the temperature of the heat transfer liquid entering the second heat exchange device / battery heater BAT, determining a target value TECH Out Tgtof the temperature of the heat transfer liquid at an outlet of the electric heater ECH, and determining a target value ThEcH_Tgt °faflow rate of heat transfer liquid through said electric heater (ECH) as a function of the flow rate values mCab Tgtand mBat Tgt,

[0084] - determining a target thermal power value (QscHj'gt') which said electric heater (ECH) shall output in order to meet the target temperature value (TECH Out Tgt) at the outlet of said electric heater (ECH).

[0085] The target thermal power value QBcH_Tgt is determined as the minimum value (41) out of a sum QEcHTgt_OL+ QECH_Tgt_CL and a maximum electric power QECHMax which can be supplied to the electric heater, wherein the second value (QECH_Max') is a design data item of the heater, whereas the first value is defined in the following fashion:

[0086] QECH_Tgt_OL is a target thermal power value calculated in open loop according to the relation

[0087] QECHTgt_OL=^ECHTgt’cp_Clnt■(TECHOut_Tgt TEEE[jn^ wherein

[0088] ThEcH_Tgt is the target value of the flow rate of heat transfer liquid through the electric heater (ECH), which in turn is determined as the maximum value out of the values of the flow rates mCab Tgtand riiBat Tgt, which are connected to the non-derated target temperature values Tcab_ClntJn_Tgt (=TCaH In HVAC Tgt) and TBat Cint In Tgt,

[0089] Cpcint is the specific heat at constant pressure of the heat transfer liquid traversing the heater ECH,

[0090] TECH_out_Tgt is the target value of the temperature of the heat transfer liquid at the outlet of the electric heater (ECH), which depends on the non-derated target temperature values TCab ant In Tgt(= TCaH In HVAC Tgt) and TBat_cint_in_Tgtr being preferably calculated as the greater between the two values, with the upper limit of a maximum temperature value of the heat transfer liquid TECH Comp Maxenvisaged by design for the same heater ECH,

[0091] TscHjn is the temperature value of the heat transfer liquid at the inlet of the electric heater (ECH), QECH_Tgt_CL is a target thermal power correction value calculated in closed loop (preferably by means of a proportional-integral control) as a function of a difference TECH Out Tgt- TECHOut, wherein TECHOutis a current temperature of the heat transfer liquid leaving the electric heater (ECH).

[0092] As it is evident from the description provided in the foregoing, each calculation lacks a reference to the derated targets.

[0093] On the contrary, referring to Figures 8 and 9 (diagrams 60 and 70) the target value ThSpiitTgtof the spill flow rate is preferably determined (in the case of a combined heating of the cabin and of the battery, which is the condition wherein the need arises of a derating as per the method according to the invention) as: a sum riispiit_Tgt_OL+ ^spiitTgtCLI wherein riispiit_Tgt_OL (diagram 60) is a spill flow rate value calculated in open loop, and mSpiit Tgt CL(diagram 70) is a spill flow rate correction value calculated in closed loop, wherein the value 'rhspiitTgtOL is determined as the minimum (block 62) out of:

[0094] - a maximum spill flow rate mSpUt Tgt ECHCabMaxto satisfy the derated target temperature value TcaH_in_Der_Drv_TgtorTCaH In Der chrg Tgt°f the heat transfer liquid at the inlet of the cabin heater CAB,

[0095] - a spill flow rate mSpiit Tgt BatTgtwhich satisfies the target value TBat ctnt In Tgtof the temperature of the heat transfer liquid at the inlet of the battery heater,

[0096] - a limit spill flow rate mSpUtTgt BatLimwhich respects a maximum temperature value TBat ctnt In Limof the heat transfer liquid at the inlet of the battery heater (BAT), a spill flow rate mSpUt Tgt ECHBatMaxwhich satisfies a value of maximum electric power consumption (QscH_Bat_Max') by the electric heater (ECH) for heating the battery of the powertrain of the vehicle, and wherein the value riT-spiitTgtCL is determined as a function (block 72, preferably a proportional-integral control) of a minimum (block 74) out of

[0097] - a difference in thermal power ^QcabTgt required to achieve the derated target temperature value TcaH_in_Der_Drv_TgtorTCaH In Der chrg Tgt°f the heat transfer liquid at the inlet of the cabin heater (CAB),

[0098] - a difference in thermal power (AQBatTgt) required to achieve the target temperature value (TBat ctnt In Tgt} of the heat transfer liquid at the inlet of the battery heater (BAT),

[0099] - a difference in thermal power (&QECH_Bat_Max} as a function of a difference QECH_Bat_Max ~ QECH_BM > wherein QECH_BM is an electric power currently absorbed for heating the battery of the vehicle powertrain, and QscH_Bat_Max is the value of maximum electric power consumption by the electric heater (ECH) for heating the battery of the vehicle powertrain.

[0100] In other words, unlike the determination of the performance target for the heater ECH, the determination of the spill flow rate Thspitt_Tgt directly depends on the derated target temperature value TCaH In Der Drv Tgtor ^CaH InDerChrgTgt•

[0101] Thanks to the method according to the invention, it is therefore possible to manage the derating of the thermal power transferred to the cabin of the vehicle in case of a full exploitation of the available thermal power, without resorting to the use of a double electric heater (one for the heat transfer liquid which enters the cabin heater CAB, one for the heat transfer liquid which enters the heating circuit of the battery BAT), thus maintaining the use of a single electric heater ECH for all the heat exchange devices of the circuit (cabin heater CAB and heating circuit of the battery BAT). This is possible through the definition of the derated target values TCaHInDerDrvTgt:, TCaH ln Der chrg Tgt, and the recalculation of the flow rate ThSpiitTgtas a function of one or of the other derated value, selected as a function of the conditions (charging or other than charging) of the vehicle, always guaranteeing the best possible conditions as regards the comfort in the cabin and the meeting of the thermal conditioning requirements - specifically the heating - of the battery in conditions of full exploitation of the thermal (and electric) power available to such ends.

[0102] Of course, the implementation details and the embodiments may amply vary with respect to what has been described and illustrated herein without departing from the extent of the present invention, as defined in the annexed claims.

Claims

CLAIMS1. A method for the operation of a thermal conditioning circuit (C), in particular a heating circuit for a vehicle with an electric powertrain, the circuit including:- a first heat exchange device (CAB) traversed by a first flow rate ('rhcab') of heat transfer liquid in a first flow direction (Fl),- an electric heater (ECH) arranged upstream of the first heat exchange device (CAB) with respect to the first flow direction (Fl) of said heat transfer liquid,- a first circulation pump (CPI) having a delivery port upstream of said electric heater (ECH) with respect to the first flow direction (Fl) of said heat transfer liquid, the first circulation pump (CPI) supplying said first flow rate (riiCab) to the electric heater (ECH) and to the first heat exchange device (CAB),- a first recirculation branch (Rl) that connects an outlet of the first heat exchange device (CAB) with a suction port of the first circulation pump (CPI),- a second heat exchange device (BAT) traversed by a second flow rate of heat transfer liquid (?iiBat) in a second flow direction (F2),- a second circulation pump (CP2) having a delivery port upstream of the said second heat exchange device (BAT) with respect to the second flow direction (F2) of said heat transfer liquid, the second circulation pump (CP2) supplying said second flow rate ('rii-Bat') to the second heat exchange device (BAT),- a second recirculation branch (R2) that connects an outlet of the second heat exchange device (BAT) with a suction port of the second circulation pump (CP2),- a first branch (Bl) configured for the transit of a spill flow rate ('rhspiit') from said first recirculation branch (Rl) to the said second recirculation branch (R2),wherein a first spill valve (VI) is arranged upstream of the first branch (Bl) to regulate the transit of the spill flow rate i'rhspiit') from said first recirculation branch (Rl) to said second recirculation branch (R2), a second branch (B2) configured for a transit of the spill flow rate (mspiit') from said second recirculation branch (R2) to said first recirculation branch (Rl), wherein a second spill valve (V2) is arranged upstream of the second branch (B2) to regulate the transit of the spill flow rate i'rhspiit') from said second recirculation branch (R2) to said first recirculation branch (Rl), the method including: determining (2, 22) a first derated target temperature value (TCaHInDerDrv Tgt) of the heat transfer liquid entering said first heat exchange device (CAB) under conditions other than vehicle charging on the basis of a nominal target temperature value (TCaH In HVAC Tgt) of the heat transfer liquid entering said first heat exchange device (CAB), of an external ambient temperature (TAmb), and preferably on the basis of a current drive mode (Drv_Mod),- determining (4, 24) a second derated temperature target value (TCaH In Der chrg Tgt) of the heat transfer liquid entering said first heat transfer device (CAB) under vehicle charging conditions as a function of a charging power (PBatt_chrg_Avi') available to a battery of the vehicle, of said nominal target temperature value (TCaH In HVAC Tgt) of the heat transfer liquid entering said first heat transfer device (CAB), and of the external ambient temperature (TAmb'),- adopting (6, 18, 26) the first derated target temperature value (TCaHInDerDrv Tgt) if the vehicle is in conditions other than vehicle charging and if there are no requests for thermal conditioning of the vehiclecabin (Special_Cabin_Conditioning_Active = 0) incompatible with adopting the first derated target temperature value (TcaH_in_Der_DrvTgt)> and controlling said thermal conditioning circuit (C) according to said first derated target temperature value (TCaH In Der Drv Tgt),- adopting (6, 18, 26) the second derated target temperature value (TCaH In Der chrg Tgt) if the vehicle is in charging condition and if there are no requests for thermal conditioning of the vehicle cabin (Special_Cabin_Conditioning_Active = 0) incompatible with adopting the second derated target temperature value (TcaH_in_Der_chrgTgt)> and controlling said thermal conditioning circuit (C) according to said second derated temperature target value <Tcan_in_DerChrgTgt>•2. The method according to claim 1, further including maintaining the nominal target temperature value (TCaH In HVAC Tgt) of the heat transfer liquid entering said first heat exchange device (CAB) if there is a request for thermal conditioning of the vehicle cabin (Special_Cabin_Conditioning_Active = 1) incompatible with adopting the first (TCaH In Der Drv Tgt) or the second (TcaHjnj)er_chrg_Tgt) derated target temperature value.

3. The method of claim 1 or claim 2, wherein the first heat exchange device is a cabin heater (CAB) in thermal exchange relationship with a cabin air flow rate ^ cabjir)' and the second heat exchange device is a battery heater (BAT) in thermal exchange relationship with a battery of said electric powertrain of the vehicle.

4. The method of claim 3, wherein determining a first derated target temperature value (TCaH In Der Drv Tgt) of the heat transfer liquid entering said cabin heater (CAB) under conditions other than vehicle charging includes determining the first derated target temperature value (TCaHInDerDrv Tgt) as the lower (42) of the nominal target temperature value (TCaH In HVAC Tgt) ofthe heat transfer liquid entering said cabin heater (CAB) and the greater (44) of:(i) a reduced temperature value of the heat transfer liquid entering the cabin heater (TCaH In Der Drv Mod Tgt) as a result of the condition other than vehicle charging and dependent on the temperature of the external environment (?Amb) and the current driving mode (Drv_Mod),(ii) a difference (46) between the nominal target temperature value (TCaH In HVAC Tgt) of the heat transfer liquid entering the cabin heater (CAB) and a value ^ TcaHinDerDrvModTgt) a reduction in the temperature of the heat transfer liquid entering the cabin heater (CAB) under conditions other than vehicle charging depending on the temperature of the external environment (T^ j,) and the current driving mode (Drv_Mod).

5. The method of claim 3 or claim 4, wherein said determination of a second derated target temperature value (TCaH In Der chrg Tgt) of the heat transfer liquid entering said cabin heater (CAB) under vehicle charging conditions includes determining the second derated target temperature value (TCaH In Der chrg Tgt) as the lower (52) of the nominal target temperature value (T'caH_in_HVAC_Tgt') of the heat transfer liquid entering the said cabin heater (CAB) and the greater value (54) of:(iii) a reduced temperature value (TCaH In Der chrg Tgt) of the heat transfer liquid entering the cabin heater (CAB) as a result of vehicle charging and dependent on the temperature of the external environment (T^ j,) and the charging power (PBatt_chrg_Avi') available to the battery of the vehicle,(iv) a difference (56) between the nominal target temperature value of the heat transfer liquid entering the cabin heater (TCaH In HVAC Tgt) and a value of a reduction in the temperature of the heat transfer liquid entering the cabin heater (CAB) under vehicle charging conditions(ATCaHin_Der_chrg_Tgt') depending on the temperature of the external environment (TAmb) and the available charging power (PsattCh.rgAvU •6. The method of any of the foregoing claims, wherein said controlling the thermal conditioning circuit (C) as a function of said first derated target temperature value includes:- determining a target value (fiicafcjr.gt) of said first flow rate (ThCab) and a target value ('diBatTgt) of said second flow rate as a function of the nominal target temperature value (TCaH In HVAC Tgt) of the heat transfer liquid entering the first heat transfer device (CAB) and an additional target value (TBat ctnt In Tgt} of the temperature of the heat transfer liquid entering the second heat transfer device (BAT),- determining a target value (TECH Out Tgt) of the temperature of the heat transfer liquid at an outlet of that electric heater (ECH) and determining a target value (ThEcH_Tgt') ofaflow rate of heat transfer liquid through that electric heater (ECH) on the basis of said target values of said first flow rate (riiCabTgt) and target value (ThBat_Tgt') of said second flow rate,- determine a target thermal power value (QscHj'gt') that the electric heater (ECH) shall output in order to meet the target temperature value (TECH Out Tgt) at the outlet of the said electric heater (ECH),- determining a target value of said spill flow rate (ritSpiit Tgt) based on said first derated target temperature value (TCaH In Der Drv Tgt) if the vehicle is in a condition other than charging and if there are no requirements for thermal conditioning of the vehicle cabin (Special_Cabin_Conditioning_Active = 0) that are incompatible with adopting the first derated target temperature value (TCaH In Der Drv Tgt), based on said second derated target temperature value (TCaH In_Der_chrg_Tgt) if thevehicle is in charging condition and if there are no requests for thermal conditioning of the vehicle cabin (Special_Cabin_Conditioning_Active = 0) incompatible with the adoption of the second derated target temperature value 'TcaH InDerChrgTgti•7. The method of claim 6, wherein said target thermal power value (QECH Tgt') is determined as the minimum value of:- a sum QECHTgt_OL+ QECHTgt_CL whereinQECH_Tgt_OL isatarget thermal power value calculated in an open loop according to the relationQECHTgt_OL=^ECHTgt’cp_Clnt■(TECHOut_Tgt TECHJTI) wherein riiECH Tgtis the target value of the flow rate of heat transfer liquid through said electric heater (ECH),cp_cint is the specific heat at constant pressure of said heat transfer liquid,TEcH_out_Tgt is a target value of the temperature of the heat transfer liquid at the outlet of said electric heater (ECH),TECHINis the temperature value of the heat transfer liquid at the inlet of the electric heater (ECH), QscH_Tgt_CL is a target thermal power correction value calculated in closed loop as a function of a difference TECH outTgt~ TECH out> wherein TECH Outis a current temperature of the heat transfer liquid leaving the electric heater (ECH), and- a maximum electrical power (QECH_MO.X') that can be supplied to the electric heater (ECH).

9. The method of claim 8, wherein the target value (m-spittj'gt') °f the spill flow rate is determined as:- a sum mSpUt Tgt 0L+ mSpUt Tgt CL, wherein mSpUt Tgt 0L(60) is a spill flow rate calculated in open loop, and rilspiit_Tgt_CL (70) is a flow rate correction value calculatedin closed loop, wherein the value riispiitTgt_OL is determined as a minimum (62) between:- a maximum spill flow rate (mSpUt Tgt ECHCabMax} to satisfy the first or second derated target temperature values (TCaH In Der Drv Tgt, TCaH In Der chrg Tgt} of the heat transfer liquid at the inlet of the cabin heater (CAB),- a spill flow rate (mSpUt Tgt BatTgt) that satisfies the target value (TBat ctnt In Tgt) of the temperature of the heat transfer liquid entering the second heat exchange device (BAT),- a limit spill flow rate (mSpUt Tgt BatLim) that respects a maximum temperature value (TBat CintInLim) of the heat transfer liquid at the inlet of the battery heater (BAT),- a spill flow rate (mSpUt Tgt ECHBatMax) that satisfies a value of maximum electrical power consumption (QECH_Bat_Max') by the electric heater (ECH) for heating the battery of the powertrain of the vehicle, and wherein the value Thspitt_Tgt_CL is determined as a function (74) of a minimum (72) of:- a difference in thermal power i&QcabTgt') required to achieve the first or second derated temperature target value (TCaH In Der Drv Tgt, TCaH In Der chrg Tgt} of the heat transfer liquid at the inlet of the cabin heater (CAB),- a difference in thermal power (&QBatTgt') required to achieve the target temperature value (TBat ctnt In Tgt) of the heat transfer liquid at the inlet of the battery heater (BAT),- a difference in thermal power (&QEcH_Bat_Max') as a function of a difference QECH_Bat_Max ~ QECH_BM > wherein QECH_BM is an electrical power currently absorbed for heating the battery of the vehicle powertrain, and QscH_Bat_Max is the value of maximum electrical power consumption by the electric heater (ECH) for heating thebattery of the vehicle powertrain.

10. The method any of the preceding claims, wherein under charging conditions there is an electrical current entering the vehicle from the outside, in particular from a charging station, and under conditions other than charging there is no electrical current entering the vehicle from the outside.

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