A method for the operation of a thermal conditioning circuit with a heat transfer liquid, comprising an electric heater, particularly a heating circuit for a vehicle with an electrical powertrain

Abstract

There is described a method for the operation of a thermal conditioning circuit (C) with a heat transfer liquid, comprising an electric heater (ECH), particularly a heating circuit for a vehicle with an electrical powertrain. The method enables using a single electric heater (ECH) for a plurality of heat exchange devices (CAB, BAT ) of the circuit (C), and specifically a single electric heater for all the heat exchange devices of the circuit.

Description

[0001] "A method for the operation of a thermal conditioning circuit with a heat transfer liquid, comprising an electric heater, particularly a heating circuit for a vehicle with an electrical powertrain"

[0002] ★★★★

[0003] TEXT OF THE DESCRIPTION

[0004] Field of the Invention

[0005] The present invention refers to thermal conditioning circuits, particularly to circuits with a heat transfer liquid. The invention was developed with particular reference to a thermal conditioning circuit with a heat transfer liquid, which operates in heat exchange relationship with a cabin and a high-voltage battery of a vehicle with an electrical powertrain, for heating either one or both of them.

[0006] Known Art

[0007] As is commonly known, the vehicles with an electrical powertrain, particularly BEVs, require a thermal conditioning system of the high-voltage battery which supplies one or more electric traction motors, in addition to the traditional heat conditioning system of the cabin. Again in a fashion known per se, said thermal conditioning systems operate both to cool the cabin and the high-voltage battery and to heat the cabin and the high-voltage battery.

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

[0009] A known configuration of a circuit for heating the cabin and the high-voltage battery comprises providing two separate circuits, each including a heat exchange device, an electric heater (so-called "ECH" - Electrical Coolant Heater) upstream of the heat exchange device, and a circulation pump. In the instance of heating a vehicle cabin, the heat exchange device is a cabin heater, arranged downstream of a cabin evaporator and hit by a flow rate of air coming from the cabin evaporator in a variable amount, according to the position of a mixing shutter. In the instance of heating the high-voltage battery, the heat exchange device comprises a circuit portion wherein the heat transfer liquid touches thermally conductive surfaces 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, so as to reach the thermal comfort target in the cabin and the operating temperature target of the high-voltage battery.

[0011] Such a solution, however, is very disadvantageous as regards its costs, since one electric heater is required respectively for each heat exchange device, with the consequent need of two control systems, and as regards the absorption (and less than optimal use) of electrical power.

[0012] Object of the Invention

[0013] The invention aims at solving the technical problems outlined in the foregoing. Specifically, the object of the invention consists in providing a method for the operation of a thermal conditioning circuit with a heat transfer liquid, comprising an electric heater, particularly a heating circuit for a vehicle with an electrical powertrain, wherein the method enables using a single electric heater for a plurality of heat exchange devices of the circuit, and particularly a single electric heater for all the heat exchange devices of the circuit. Summary of the Invention

[0014] 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.

[0015] Brief Description of the Figures

[0016] The invention will now be described with reference to the annexed Figures, which are provided by way of non-limiting example only and wherein:

[0017] Figure 1 shows a thermal conditioning system wherein a method according to the invention may be implemented,

[0018] Figures 2 to 11 respectively show exemplary diagrams of determinations operated in the implementation of the method according to the invention. Detailed Description Reference C in Figure 1 generally denotes a thermal conditioning circuit, particularly a heating circuit for a vehicle with an electrical powertrain, which is used as an example for describing the implementation of the method according to the invention.

[0019] The circuit C comprises:

[0020] - a first heat exchange device CAB, which in the specific example illustrated herein is a cabin heater for heating a flow rate mCab Airof air supplied to a cabin of the vehicle, and which is traversed by a first flow rate frtcab of heat transfer liquid in a first flow direction Fl,

[0021] - an electric heater ECH, arranged upstream of the first heat exchange device CAB in relation to the first flow direction Fl of the heat transfer liquid,

[0022] - a first circulation pump CPI, having a delivery port arranged upstream of the electric heater ECH in relation 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,

[0023] - a first recirculation branch R1 connecting an outlet of the first heat exchange device CAB with a suction port of the first circulation pump CPI,

[0024] - 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), traversed by a second flow rate of heat transfer liquid mBatin a second flow direction F2,

[0025] - a second circulation pump CP2 having a delivery port arranged upstream of the second heat exchange device BAT in relation 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,

[0026] - a second recirculation branch R2 which connects an outlet of the second heat exchange device BAT with a suction port of the second circulation pump CP2,

[0027] - a first branch Bl configured for the transit of a spill flow rate ritspitt from the first recirculation branch 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 ritspitt from said first recirculation branch R1 to the second recirculation branch R2 (the phrase "regulate the transit of the spill flow rate indicates that the valve VI is configured to deliver a flow rate ritspitt to the branch R2 in a continuously variable amount - thus varying a throttle degree of the same valve - between a null flow rate and a maximum flow rate allowed by the valve VI itself, which may ultimately be equal to frtcab'i /

[0028] - a second branch B2 configured for a transit of a spill flow rate rii-spiit from the second recirculation branch R2 to the first recirculation branch Rl, in which 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 indicates that the valve V2 is configured to deliver a flow rate riispiit to the branch Rl in a continuously variable amount - thus varying a throttle degree of the same valve - between a null flow rate and a maximum flow rate allowed by the valve VI itself, which may ultimately be equal to riiBat).

[0029] 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 riispiit other than zero - in the sections of the recirculation branches Rl, R2 downstream of the respective valve VI, V2 (which are denoted as RIA, R2A), a flow rate of recirculation heat transfer liquid 'ri'icabRic, mBatRic flows having an amount 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 confluence nodes between the flow rate of the recirculation heat transfer liquid ThCab Ric, mBat Ric(respectively) and the spill flow rate mSplit.

[0030] As regards the valves VI and V2, they are preferably implemented as three-port valves with a continuous positioning, so that they enable regulating the spill flow rate ritspitt described in the foregoing, with the following hydraulic connection arrangement:

[0031] - 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 of the branch Bl. The first and the second port are always in fluid communication, except when the spill flow rate ritspitt coming from the branch R1 equals the flow rate frtcab• This enables ensuring in any case the recirculation of the spill flow rate ritspitt towards the suction port of the pump CPI when the flow rate mCabis greater than the spill flow rate rii-spiitr whereas the third port is in fluid communication with the first port (and the second port) in a variable amount, depending on the entity of the spill flow rate rii-spiitr and it is isolated, thereby in turn isolating the recirculation branch R1 (and, globally, the circuit comprising the heater ECH and the first device CAB) from the recirculation branch R2 only when the spill flow rate ritspitt is null;

[0032] - 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 ritspitt coming from the branch R1 equals the flow rate . This ensures in any case the suction flow rate to the pump CP2, as well as the recirculation of the flow rate 'rhBat(either total or reduced to the flow rate ThBat Ric) towards the suction port of the pump CP2 when the flow rate is greater than the spill flow rate ritspitt• The third port is in fluid communication with the first port (and the second port) in a variable amount, depending on the entity of the spill flow rate rii-spiitr and it is isolated, thereby in turn isolating the recirculation branch R1 (and, globally, the circuit comprising the heater ECH and the first device CAB) from the recirculation branch R2 only when the flow rate ritspitt is null or when the flow rate is null. The fluid communication between the first and the third port of the valve V2, moreover, ensures that, when the first and the second port of the valve VI are isolated (or in any case are not subject to the transit of a flow rate), due to mSplit= mCab, the flow rate recirculation will take place to the suction of the pump CPI in any case.

[0033] As a general prescription, every reference to a "flow rate" in the present description must be construed as a reference to a mass flow rate, as confirmed by the choice of the notation m for all the flow rates.

[0034] 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,

[0035] - a sensor TS_ECH_OUT, configured to detect the temperature of the heat transfer liquid at the outlet the heater ECH (thus at the inlet of the first heat exchange device / heater CAB), a sensor TS_AIR_IN, configured to detect the temperature of the flow rate of air mCab Airwhich hits 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,

[0036] - 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.

[0037] That being said, according to the invention the method comprises:

[0038] - determining at least one of a target value mCab Tgtof the first flow rate mCaband a target value mBat Tgtof the second flow rate mBatas a function of, respectively, a first target value TCab Clnt In Tgtof the temperature of the heat transfer liquid at the inlet of the first heat exchange device CAB (in this case, specifically, the cabin heater CAB) and of a second target value TBat Clnt In Tgtof the temperature of the heat transfer liquid at the inlet of the second heat exchange device, determining a target value TECH 0UT Tgtof the temperature of the heat transfer liquid at an outlet of the electric heater ECH, and determining a target value riiECH Tgtofaflow rate of the heat transfer liquid through the electric heater ECH as a function of at least one of the target value mCab Tgtof the first flow rate mCaband the target value mBat Tgtof said second flow rate W-Batr

[0039] - determining a target thermal power value QscH_Tgt which said electric heater must develop in order to meet the target temperature value TECH 0UT Tgtat the outlet of the electric heater ECH,

[0040] - determining a target value ritspiitTgt of the spill flow rate ihsputas afunction of the target thermal power value QscH_Tgt and of said at least one of the target value mCab Tgtof the first flow rate mCabof heat transfer liquid and the target value mBat Tgtof said second flow rate mBat.

[0041] As will be apparent from the following description, the calculations and the determinations of the method according to the invention depend on the heating requests which are sent (with the intermediation of respective electronic controllers) to the circuit C. Specifically, they depend on whether a heating action is required only from the first heat exchange device CAB (cabin heating only), only from the second heat exchange device BAT (battery heating only), both from CAB and BAT (both cabin and battery heating), or from neither. For example, upstream of the method, determining at least one of the target value mCab Tgtof the first flow rate mCaband the target value ^BatTgt of the second flow rate comprises determining the respective target value if a heating action is required by means of the respective heat exchange device CAB or BAT. Such a plurality of calculation and determination processes is shown in the Figures 2 to 11 as a selection criterion, and will now be described in detail particularly with reference to the implications thereof. The description will be set forth with reference to the circuit C equipping a vehicle with an electrical powertrain; therefore, the first heat exchange device CAB is a cabin heater, whereas the second heat exchange device BAT is a battery heater. Of course, the method is applicable to any circuit C having a similar structure and similar needs.

[0042] The first target temperature value TCab Clnt InTgtof the heat transfer liquid at the inlet of the cabin heater CAB is defined, in the same way as the target value ^cabjrgt of the first flow rate mCab, by a control logic of the thermal conditioning of the cabin, and therefore such values represent input data for the method according to the invention. On the contrary, the second target temperature value TBat Clnt In Tgtof the heat transfer liquid at the inlet of the battery heater is determined, in the method according to the invention, on the basis of the diagram denoted by reference 10 in Figure 2. Specifically, it is determined as the minimum value (block 11) of:

[0043] - a sum (block 12) of a target temperature value TBatTgt°f the battery of the electrical powertrain and a target temperature increase / \TBatTgtdetermined as a function of a target heating thermal power QBat_Tgt f°rthe battery. The latter constitutes an input item of data for reading the value &TBatTgtfrom a map MIO, which provides values of temperature increase &TBatas a function of the heating power for the battery Qgat' therefore, the map MIO provides the value &TBatTgtin response to a input item of data QBatTgt!

[0044] - a temperature limit value TBat Clnt In Limof the heat transfer liquid at the inlet of the battery heater BAT.

[0045] Once the value TBat Clnt In Tgthas been determined, it is possible to determine the target temperature value TEcH_out_Tgt of the heat transfer liquid at the outlet of the electric heater ECH, Figure 3, diagram 20. This includes selecting the minimum value (block 21) of:

[0046] - the second temperature target value TBat Clnt In Limof the heat transfer liquid at the inlet of the battery heater BAT and a maximum temperature value TECH Comp Maxat the outlet of the electric heater ECH (being the maximum value which can be tolerated by the heater ECH in order to safeguard the component), if only a heating of the battery of the electrical powertrain via the battery heater BAT is required (condition B20 "request for battery heating only", switch 22 - generally speaking, each switch follows the path shown in the diagrams if the control condition shown in the box, B20 in the present case, is satisfied),

[0047] - the first target temperature value TCab Clnt InTgtof the heat transfer liquid at the inlet of the cabin heater CAN and the maximum temperature value TECH Comp Maxat the outlet of the electric heater ECH if only heating of the vehicle cabin via the cabin heater CAB is required (condition C20 "request for cabin heating only", switch 23), - the maximum value (block 24) between the first target temperature value TCab Clnt In Tgtof the heat transfer liquid at the inlet of the cabin heater CAB and the second target temperature value TBat Clnt In Limof the heat transfer liquid at the inlet of the battery heater BAT, and the maximum temperature value TECH Comp Maxat the outlet of the electric heater ECH, if both heating of the vehicle cabin via the cabin heater and heating of the battery of the electrical powertrain via the battery heater are required (neither the condition B20 "request for battery heating only" nor the condition BC20 "request for cabin heating only" are satisfied, whereas the condition BC20 "cabin or battery heating" is satisfied, always with the mediation of the switch 25, which is controlled by the condition BC20),

[0048] - a current temperature value TECH Outof the heat transfer liquid at the outlet of the electric heater ECH and the maximum temperature value TECH Comp Maxat the outlet of the electric heater ECH if neither heating of the cabin of the vehicle via the cabin heater CAB, nor heating of the battery of the electrical powertrain via the battery heater BAT are required (neither the condition B20 "request for battery heating only" nor the condition C20 "request for cabin heating only" are satisfied, in the same way as the condition BC20 "cabin or battery heating" is not satisfied, always with the mediation of the switch 25, which is controlled by the condition BC20; the latter not being satisfied leads to the switching of the switch 25 to TECH Out).

[0049] With reference to Figure 4, reference 30 denotes a diagram exemplifying the determination of the target value ThECHTgtof the flow rate mECHof the heat transfer liquid through the electric heater ECH. Such a determination comprises:

[0050] - determining the target value ThECHTgtof the heat transfer liquid flow rate TTT-ECH through the electric heater ECH as the maximum value (block 31) between the target value mBat Tgtof the second flow rate mBatand a minimum value TTT-ECH_comp_Min of the heat transfer liquid flow rate through the heater ECH if only heating of the battery of the electrical powertrain via the battery heater BAT is required (condition B30 "request for battery heating only", switch 32, in combination with the condition C30 "request for cabin heating only" not being satisfied, switch 33, plus final mediation with the switch 34 controlled by a condition BC30 "request for cabin or battery heating" which, being satisfied, selects the output of block 31 as an output item of data of the switch 34),

[0051] - determining the target value riiECH Tgtof the heat transfer liquid flow rate 'rhECHthrough said electric heater ECH as the maximum value (block 31) between the target value mCab Tgtof the first flow rate mCaband the minimum flow rate value mECH Comp Mtnof the heat transfer liquid through the heater ECH if only heating of the vehicle cabin via the cabin heater is required (the condition C30 "request for cabin heating only" is satisfied, switch 33, plus final mediation with the switch 34 being controlled by the condition BC30 "request for cabin or battery heating", which, being satisfied, selects the output of the block 31 as an output item of data 31 of the switch 34),

[0052] - determining the target value riiECH Tgtof the heat transfer liquid flow rate MECH through the electric heater as the maximum value of the greater (block 35) of said target value of the first flow rate riiCab Tgtand target value of the second flow rate T^-BatTgt / and a minimum value TTT-ECH_comp_Min of the heat transfer liquid flow rate through the heater ECH if both heating of the vehicle cabin via the cabin heater and heating of the battery of the electrical powertrain via the battery heater are required (neither the condition B30 "request for battery heating only" or the condition C30 "request for cabin heating only" satisfied, whereas the condition BC30 "request for cabin or battery heating" is satisfied, plus final mediation with the switch 34, which is controlled by the condition B30 which, being satisfied, selects the output of the block 31 as an output item of data of the switch 34),

[0053] - determining the target value riiECH Tgtof the heat transfer liquid flow rate MECH through the electric heater ECH as a null value ("0", block 36) if neither heating the cabin of the vehicle via the cabin heater, nor heating of the battery of the electrical powertrain via the battery heater are required (the condition BC30 is not satisfied, and the block 36 is selected as output of the switch 34).

[0054] By determining the flow rate MECH Tgt it is moreover possible to calculate a current value TCab Outof the temperature of the heat transfer liquid at the outlet of the first heat exchange device (cabin heater) CAB) as a function of a current value TECHof the temperature of the heat transfer liquid at the outlet of the electric heater ECH and of the target value riiECH Tgtof the heat transfer liquid flow rate through the electric heater ECH. In detail, the current temperature value at the outlet of the cabin heater CAB is determined as: rp, _ '-r TECH Out~ Tcab_AlTjn

[0055] *Cab_Out *ECH_Out ~

[0056] KThCab ’mECH_Tgt'cp_Clnt wherein:

[0057] Tcab_out is the current temperature value at the outlet of the cabin heater CAB

[0058] TEcH_out is the current temperature value of the heat transfer liquid at the outlet of the electric heater ECH TCabAir_in is a value of the temperature of the air supplied to the cabin which hits the cabin heater at the inlet section thereof (it is measured by the sensor TS_AIR_IN) RTbcab isathermal resistance of the cabin heater CAB, riiECH Tgtis the target value of the flow rate of the heat transfer liquid 'rhECHthrough the electric heater ECH,cp_cint is the specific heat at constant pressure of the heat transfer liquid.

[0059] With reference to the Figures 5 and 6, the value of thermal resistance of the cabin RTb Cabis extracted from a map M37 which uses the flow rate value 'rhECH Tgton the x-axis, and air iso-flow curves parametrized as a function of the air flow rate mCab Air. In order to read the value RrhCab, the map M37 is accessed with the flow rate value 'rhECH Tgtuntil intercepting the corresponding air iso-flow curve (by way of example, four iso-flow curves mCab Airl, mCab Air2, mCab Air3, mCab Air4 are shown), and from this the value RTtlcab is found on the y-axis. As regards, upstream of the reading of the map M37, the flow rate 'rhcabAir, the latter is in turn extracted from a map M38, which uses a value of rotational speed of a cabin fan nBLon the x-axis and iso-position curves FP referred to a mixing shutter, which determines the fraction of the inlet section of the cabin heater CAB which is hit by the air flow rate mCab Aircoming from a cabin evaporator, which is part of a refrigeration cycle cooling circuit, which is known per se. The curves FP are parametrized with respect to different positions of the mixing shutter.

[0060] In order to read the value mCab Airthe map M38 is accessed with the value of rotational speed nBLuntil intercepting the corresponding iso-position curve of the shutter (by way of example, four iso-position curves FP1, FP2, FP3, FP4 are shown), and from this the valuer^lcab_Atronthe y-axis is found.

[0061] Reference number 40 in Figure 7 generally denotes a diagram representative of the determination of the target thermal power value QEcH_Tgt- In detail, the target thermal power value is determined as the minimum value (block 41) of:

[0062] - a sum (block 42) QEcHTgtOL + QECHTSI_CL wherein

[0063] QECH_Tgt_OL isatarget thermal power value calculated in an open loop according to the relationship

[0064] QECHTgt_OL=^ECHTgt’cp_Clnt'(TECH_OutTgt~ ?ECH In) (blocks 43, 44) wherein

[0065] ThEcH_Tgt is the target value of the flow rate of heat transfer liquid through the electric heater ECHcp_cint is the specific heat at constant pressure of the heat transfer liquid,

[0066] TECH_out_Tgt is the target temperature value of the heat transfer liquid at the outlet of the electric heater ECH,

[0067] TECHINis the temperature value of the heat transfer liquid at the inlet of the electric heater ECH,

[0068] QEcHTgt_CL is a correction value of the target thermal power calculated in a closed loop as a function of a difference TECH Out Tgt- TECH Out(block 45), wherein TECH Outis the current temperature of the heat transfer liquid at the outlet of the electric heater ECH. Such a difference is an input item of data for a proportionalintegral controller 46, the output whereof is the correction QECHTgt_CL>

[0069] - a maximum electrical power QECH_MUX that can be supplied to the electric heater; the maximum electrical power QEcH_Max represents a maximum electrical power that can be used for heating via the heater ECH. Generally speaking, in the context of the present description it is possible to refer indifferently to the electrical power or to the thermal power as regards the heater ECH, since the electrical-thermal conversion yield of the heater ECH is substantially unitary. Reference number 50 in Figure 8 generally denotes a diagram representative of the determination of the maximum electrical power value QECHMOX- In detail, this comprises determining the value of the maximum electrical power QECH_MO.XASthe minimum value (block 51) of:

[0070] - a maximum electrical power QECH BatMax which can be used for heating the battery via the heater BAT and a maximum electrical power QECH_comp_Max that can be tolerated by the heater ECH if only heating of the battery of the electrical powertrain via the battery heater BAT is required (condition B50 "request for battery heating only", switch 52, in combination with the condition C50 "request for cabin heating only" not being satisfied, switch 53, plus final mediation with the switch 54 which is controlled by a condition BC50 "request for cabin or battery heating" which, being satisfied, selects the output of the switch 53 as an input item of data into the block 51),

[0071] - a maximum electrical power QscH_cab_Max that can be used for heating the cabin via the heater CAB and the maximum value of electrical power QECH_comp_Max that can be tolerated by the heater ECH if only heating of the vehicle cabin via the cabin heater CAB is required (the condition B50 "request for battery heating only" is not satisfied, switch 52, the condition C50 "request for cabin heating only" is satisfied, switch 53, plus final mediation with the switch 54, which is controlled by the condition BC50 "request for cabin or battery heating", which being satisfied selects the output of the switch 53 as an input item of data into block 51),

[0072] - a sum of the maximum electrical powers QECH BatMax and QscH_cab_Max (block 55) and the maximum value of electrical power QECH_comp_Max tolerable by the heater ECH if both heating of vehicle cabin via the cabin heater CAB and heating of the battery of the electrical powertrain via the battery heater BAT are required (neither the condition B50 "request for battery heating only", switch 53, nor the condition C50 "request for cabin only", switch 53, are satisfied, whereas the condition BC50 "request for cabin or battery heating" is satisfied, plus final mediation with the switch 54, which is controlled by the condition BC50 which, being satisfied, selects the output of switch 53 as an input item of data into block 51),

[0073] - the null value ("0", block 56) and the maximum value of electrical power QECH_comp_Max that can be tolerated by the heater ECH if neither heating of the vehicle cabin via the cabin heater CAB, nor heating of the battery of the electrical powertrain via the battery heater BAT are required (neither the condition B50, "request for battery heating only", switch 53, nor the condition C50 "request for cabin heating only", switch 53, are satisfied, in the same way as the condition BC50 "cabin or battery heating" is not satisfied, plus final mediation with switch 54, which is controlled by the condition BC50 which, not being satisfied, selects block 56 as an input item of data into block 51).

[0074] Reference number 60 in figure 9 generally denotes a diagram representative of the determination of the target spill flow rate value ThSpUt Tgt. In detail, this comprises determining the value of the spill flow rate as:

[0075] - a sum mSplitTgt0L+ mSplitTgtCL(block 61), wherein ThSpiit TgtOL isaspill flow rate value calculated in an open loop, and mSplit Tgt CLis a spill flow rate correction value calculated in a closed loop, if both heating of the vehicle cabin via the cabin heater CAB, and heating of the electrical powertrain battery via the battery heater BAT are required (the condition B60 "request for battery heating only" is not satisfied, switch 62, in combination with neither the condition C60 "request for cabin heating only" or NBC60 "no request for cabin or battery heating", connected by "OR" (block 63), being satisfied, switch 64, the latter being controlled by the logic state of the block 63 which, being "FALSE" in the present case, selects the output of the switch 62 as the value of ThSpUtTgtoutput from the switch 64),

[0076] - the target value ThBatTgtof the second flow rate mBatif only heating of the battery of the electrical powertrain via the battery heater BAT is required (the condition B60 "request for battery heating only" is satisfied, switch 62, in combination with neither the condition C60 "request for cabin heating only" nor the condition NBC 60 "no request for cabin or battery heating", being connected by "OR" (block 63), being satisfied, switch 64, the latter being controlled by the logic state of block 63, which, being "FALSE" in the present case, selects the output of the switch 62 as the value of ThSpUtTgtoutput from switch 64),

[0077] - a null value ("0", block 65) if neither heating the vehicle cabin via the cabin heater CAB nor heating of the electrical powertrain battery via the battery heater BAT are required, or if only heating of the vehicle cabin via the cabin heater CAB is required (the condition B60 "request for battery heating only" is not satisfied, switch 62, in combination with the condition C60 "request for cabin heating" being satisfied and NBC60 "no request for cabin or battery heating" not being satisfied, connected by "OR" (block 63), switch 64, the latter being controlled by the logic state of the block 63 which, being "TRUE" in the present case, selects the output of the block 65 ("0") as the value of ThSpUtTgtoutput from switch 64). In both such cases, there is no spill flow rate, since heating of the battery is not required, and therefore in both such cases the valves VI and V2 are in the closed position.

[0078] Reference number 70 in Figure 10 generally denotes a diagram representative of the determination of the spill flow rate value calculated in an open loop ^spiit_Tgt_OL•Indetail, the value mSplit Tgt 0Lis determined as a minimum (block 72) of:

[0079] - a maximum spill flow rate ThSplit Tgt ECHCabMaxto ensure compliance with the target temperature TCab In Tgtof the heat transfer liquid at the inlet of the cabin heater CAB, particularly considering the total maximum heating thermal power QECH_MUX and a thermal power surplus Qneatjiec available in the circuit assigned to the cabin (which includes the heater CAB) thanks to thermal recovery actions. This can be calculated according to the following relationship

[0080] > . T^dijout ^ECH In Lim mSplitTgt_ECHCabMax ~mECHTgt

[0081] *Cab_Out *Bat_Clnt_Out wherein TECH In Limis a minimum temperature of the heat transfer liquid at the inlet of the heater ECH in order to comply with the temperature target TCab In Tgtwith a flow rate of heat transfer liquid ThECH_Tgtr and considering the total maximum heating thermal power QECH_MO.X and a surplus of thermal power Qneat_Rec available in the circuit assigned to the cabin (comprising the heater CAB) thanks to thermal recovery actions. In turn, TEcH_in_LimmaY be calculated as r QECHMax+ Qlleat_Rec

[0082] *ECHJn_Lim ~ *Cab_In_Tgt • Cab_In_Safety

[0083] PcintmECHTgtwherein &TCab In Safetyis a temperature safety margin to avoid the risk of insufficient heating of the cabin in case the heating of the cabin is required.

[0084] - a spill flow rate mSpUt Tgt BatTgtwhich satisfies the temperature target TBat Clnt In Tgtof the heat transfer liquid at the inlet of the battery heater BAT. This can be calculated by means of the following relationship

[0085] _ rilBatTgt(TBatClnt_In_Tgt~ TBatClntOut)'

[0086] ™Split__TgtBatTgt y

[0087] *Cab_Out *Bat_Clnt_Out a limit spill flow rate rii-sputTgtBatLim which complies with a maximum value of temperature TBat Clnt In Limof the heat transfer liquid at the inlet of the battery heater BAT. This may be calculated as

[0088] > ^Bat_Tgt(j^Bat_Clnt_In_Lim TBatClntOut)'

[0089] ^SplitTgtBatLim ~ > y

[0090] *Cab_Out *Bat_Clnt_Out

[0091] - a spill flow rate mSplit Tgt ECHBatMaxwhich complies with a value of maximum consumption of electrical power QscH_Bat_Max by the electric heater ECH for heating the battery of the vehicle powertrain. This may be calculated as

[0092] > QECH_Bat_Max

[0093] ^-SplitTgtECHBatMax ~ > y

[0094] *Cab_Out *Bat_Clnt_Out

[0095] The reference number 80 in Figure 11 generally denotes a diagram representative of the determination of the correction value of the spill flow rate calculated in an open loop mSplitTgtCL. In detail, the value mSplitTgtCLis determined as a function (by means of a proportionalintegral controller 82) of a minimum (block 84) of:

[0096] - a thermal power difference kQcabTgt required to achieve the target temperature value TCab Clnt In Tgtof the heat transfer liquid at the inlet of the cabin heater CAB, particularly considering the maximum available heating power QECH_MO.X and the target electrical power QscH_Tgt- The difference kQcabjgt may he calculated as:

[0097] ^QcabTgt~ QECH_MCIX QECH Tgt ^ECHTgt'cpcint\Tcab_Clnt_InTgt

[0098] ~ Tcab_Clnt_In) wherein TCab Clnt Inis a current temperature of the heat transfer liquid at the inlet of the heater CAB;

[0099] - a thermal power difference / \QBatTgt required to reach the target temperature value TBat Clnt In Tgtof the heat transfer liquid at the inlet of the battery heater BAT. This may be calculated as

[0100] BatTgt~ ™Bat_Tgt'^pcint(j^Bat_Clnt_In_Tgt ^BatClntIrC) wherein TBat clnt Inis a current temperature of the heat transfer liquid at the inlet of the heater BAT. If &QBat_Tgt> 0, additional thermal power is necessary to reach the target TBat Clnt In Tgt; a thermal power difference ^QscH_Bat_Max being function of a difference QEcH_Bat_Max ~ QECH_Bat> wherein QscH_Bat isanelectrical power currently absorbed for heating the battery of the vehicle powertrain, which may be calculated as QECH_Bat=^BatTgt■cpcint(TBat_Clnt_In ~ TBat_cint_out)•Thepower QECH_Bat is directly considered as electrical power since, as already stated in the foregoing, the conversion yield of the heater ECH is substantially unitary.

[0101] Thanks to the determination of the spill flow rate ThSput Tgton the basis of the performance targets described herein it is therefore possible - by simply regulating the amount of the flow rate riispiit which transits between the recirculation branches R1 and R2 (thus between the respective circuits) - to use a single electric heater ECH for both heaters CAB and BAT, providing both with a pre-heated flow rate of heat transfer liquid, which makes it more rapid and more efficient to achieve the envisaged heating targets.

[0102] Of course, the implementation details and the embodiments may be amply varied 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), particularly a heating circuit for a vehicle with an electric powertrain, the circuit comprising:- 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) in relation to the first flow direction of the heat transfer liquid,- a first circulation pump (CPI) with a delivery port arranged upstream of said electric heater (ECH) in relation to the first flow direction (Fl) of the said heat transfer liquid, the first circulation pump (CPI) supplying said first flow rate (ThCab) to the electric heater (ECH) and to the first heat exchange device (CAB),- a first recirculation branch (Rl) connecting 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 ('ri'tBat') inasecond flow direction (F2),- a second circulation pump (CP2) with a delivery port arranged upstream of the second heat exchange device (BAT) in relation 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) connecting 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 i'rhspiit') from the first recirculation branch (Rl) 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 i'rhspiit') from said first recirculation branch (Rl) to the second recirculation branch (R2), a second branch (B2) configured for a transit of the spill flow rate i'rhspiit') from said second recirculation branch (R2) to the said first recirculation branch (Rl), in which a second tap valve (V2) is placed 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 at least one of a target value (riiCab Tgt) of said first flow rate (mCab') and a target value (riiBat Tgt} of said second flow rate ('rii-Bat')as afunction of, respectively, a first target value (TCab Clnt In Tgt} of the temperature of the heat transfer liquid entering the first heat exchange device (CAB) and a second target value (TBat Clnt In Tgt) of the temperature of the heat transfer liquid entering the second heat exchange device (BAT),- determining a target value (TECH Out Tgt} of the temperature of the heat transfer liquid at an outlet of said electric heater (ECH) and determining a target value (ThEcH_Tgt') ofaflow rate of heat transfer liquid through said electric heater (ECH) as a function of at least one of a target value of said first flow rate (riicab_Tgt') and a target value (riiBat Tgt} of said second flow rate,- determining a target thermal power value (QECH_Tgt') to be developed by said electric heater (ECH) in order to meet that target temperature value (TECH Out Tgt} at the output of said electric heater (ECH),- determining a target value of said spill flow rate (riispiit_Tgt}onthe basis of said target thermal power value (QECH_Tgt') and at least one of said target value(riicabTgt'l of that first flow rate (riiCab} and said target value ('rhBat Tgt') °f said second flow rate (ThBat).

2. The method of claim 1, wherein the determination of at least one of a target value (riicabj'gt') of said first flow rate (ThCab) and a target value (riiBatj'gt') of said second flow rate (^Bat) includes determining the respective target value (riicab_Tgtr m-cabj'gt') if a heating action is required by means of the corresponding heat exchange device (CAB, BAT).

3. The method of claim 1 or claim 2, wherein said first heat exchange device (CAB) is a cabin heater for heating a cabin of the vehicle, and said second heat exchange device (BAT) is a battery heater for heating a battery of said electric powertrain.

4. The method of claim 3, wherein said second target temperature value (TBat Clnt In Tgt} of the heat transfer liquid entering the battery heater (BAT) is determined as the minimum value of:- a sum of a target temperature value (TBat Tgt) of the battery of the electric powertrain and a target temperature increase (&TBat Tgt) determined as a function of a target heating thermal power (QECH_Tgt') f°rthe battery, and- a temperature limit value (TBat Clnt In Lim) of the heat transfer liquid entering the battery heater (BAT).

5. The method of claim 4, wherein determining a target value (TECH Out Tgt} of the temperature of the heat transfer liquid at the outlet of said electric heater (ECH) includes selecting the minimum value (21) among: the second target value (TBat Clnt In Tgt} of the heat transfer liquid entering the battery heater (BAT) and a maximum temperature value (TECH Comp Max} at the outlet of the electric heater (ECH) if only a heating of the battery (B20, 22) of the electric powertrain via the battery heater (BAT) is required,- the first target temperature value (TCabcintjnjgt) of the heat transfer liquid entering the cabin heater (CAB) and the maximum temperature value (TECH Comp Max} at the outlet of the electric heater if only heating of the vehicle cabin via the cabin heater (CAB) is required (C20, 23), the maximum value (24) between the first target temperature value (TCab Clnt In Tgt) of the heat transfer liquid entering the cabin heater (CAB) and the second target temperature value (TBat Clnt In Tgt) of the heat transfer liquid entering the battery heater, and the maximum temperature value (TECH Comp Max} at the outlet of the electric heater (ECH) if both heating of the vehicle cabin via the cabin heater (CAB) and heating of the battery of the electric powertrain via the battery heater (BAT) are required, a current temperature value (TECH Out) of the heat transfer liquid at the outlet of said electric heater (ECH) and the maximum temperature value (TECH Comp Max} at the outlet of the electric heater (ECH) if neither heating of the cabin of the vehicle via the cabin heater (CAB) nor heating of the electric powertrain battery via the battery heater (BAT) are required (25).

6. The method of any of the preceding claims, wherein said determination of a target value (riiECH_Tgt') of a flow rate of heat transfer liquid through said electric heater (ECH) includes:- determining the target value (riiECH_Tgt') of the heat transfer fluid flow rate through the electric heater (ECH) as the maximum value (31) between the target value of that second flow rate (mBatTgt') and a minimum value (mECH Comp Mtn) of the heat transfer fluid flow rate through the electric heater (ECH) if only a heating of the battery of the electric powertrain via the battery heater (BAT) is required,- determining the target value (riiECH_Tgt') of the heattransfer fluid flow rate through the electric heater (ECH) as the maximum value (31) between the target value of that first flow rate ('rhcabTgt^ and the minimum flow rate value of heat transfer fluid through the electric heater (mECH Comp Mtn) if only heating of the vehicle cabin by the cabin heater (CAB) is required,- determining the target value (riiECH_Tgt') of the heat transfer liquid flow rate through said electric heater (ECH) as the maximum value (31) of the greater (35) of said target values of the said first flow rate (riicabj'gt') and target value of the said second flow rate (ThBat Tgt}r and the minimum value ^ ECH_comp_Mvn) °f the heat transfer liquid flow rate through said electric heater (ECH) if both a heating of the vehicle cabin via the cabin heater (CAB) and a heating of the battery of the electric powertrain via the battery heater (BAT) are required,- determining the target value of the heat transfer fluid flow rate through that electric heater as a null value (36) if neither heating the cabin of the vehicle via the cabin heater (CAB) nor heating of the battery of the electric powertrain via the battery heater (BAT) are required.

7. The method of claim 6, further including determining a temperature value (TCab Out) of the heat transfer liquid at the outlet of cabin heater (CAB) as a function of a current value (TECH Out) of the temperature of the heat transfer liquid at the outlet of said electric heater (ECH) and of that target value (riiECH_Tgt') of the heat transfer liquid flow rate through that electric heater (ECH), where the current temperature value (TCab Out) at the outlet of said cabin heater is determined as: rp, _ ’-r TECH_OIU:~ Tcab_Alr_In*Cab_Out~ *ECH_Out ~KThCab ’mECH_Tgt'cp_Clnt wherein:Tcab_out is the current temperature value at the outlet ofsaid cabin heater (CAB),TEcH_out is the current temperature value of the heat transfer liquid at the outlet of said electric heater (ECH),TCabAir_in is a value of the temperature of the air supplied to the cabin that hits said cabin heater (CAB) at an inlet section of the cabin heater,Rrh_cab is a thermal resistance of the cabin heater (CAB), ThEcH_Tgt is 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.

8. The method according to any of claims 5 to 7, wherein said target thermal power value (QscHj'gt') is determined as the minimum value (41) of: - a sum (42) QECH_Tgt_OL + QECH_Tgt_CLr whereinQECHTgt_OL is a target thermal power value calculated in an open loop according to the relationshipQECHTgt_OL=^ECHTgt’cp_Clnt■(TECH_Out_Tgt TEEp[jn) whereinThEcH_Tgt is 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 the target temperature value 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), QECHTgt_CL is a correction value of the target thermal power calculated in a closed loop as a function of a difference TECH Out Tgt- TECH Out, wherein TECH Outis a current temperature of the heat transfer liquid leaving the electric heater (ECH), anda maximum electrical power (QECH_MO.X') that can be supplied to the electric heater.

9. The method of any of the preceding claims, where the target value (ThSpUt Tgt) of the spill flow rate is determined as:- a sum mSplit Tgt 0L+ mSplit Tgt CL, wherein mSplit Tgt 0Lis an open-loop spill flow rate value, and riispiit_Tgt_CL isaclosed-loop tappet flow correction value, if both a heating of the vehicle cabin via the cab heater (CAB) and a heating of the electric powertrain battery via the battery heater (BAT) are required,- the target value of the second flow rate (riiBat Tgt} if only heating of the battery of the electric powertrain via the battery heater (BAT) is required, a null value (65) if neither heating the vehicle interior via the cabin heater (CAB) nor heating of the electric powertrain battery via the battery heater (BAT) are required, or if only heating of the vehicle cabin via the cabin heater (CAB) is required.

10. The method of claim 9, wherein the value ThSpiit Tgt 0L is determined as a minimum of:- a maximum spill flow rate (mSplit Tgt ECHCabMax) to ensure compliance with the target temperature value ^cab_cint_in_Tgt') of the heat transfer liquid at the inlet of the cabin heater (CAB),- a spill flow rate (Thspiit_Tgt_BatTgt'> that satisfies the temperature target (TBat Clnt In Tgt) of the heat transfer liquid at the inlet of the battery heater,- a limit spill flow rate (mspiitj'gt_BatLtm') that respects a maximum temperature value (TBat Clnt In Lim) of the heat transfer liquid at the inlet of the battery heater (BAT), a spill flow rate (mSplit Tgt ECHBatMax) that respects a value of maximum electrical power consumption (QscH_Bat_Max} by the electric heater (ECH) for heating the battery of the vehicle powertrain, andwherein the value thspiitTgtCL is determined as a function of a minimum of: a thermal power difference (AQcabj'gt') required to achieve the target temperature value (TCab Clnt In Tgt} of the heat transfer liquid at the inlet of the cabin heater (CAB),- a thermal power difference {^QgatTgt) required to reach the target temperature value (TBat Clnt In Tgt} of the heat transfer liquid at the inlet of the battery heater (BAT), - a thermal power difference (&QEcH_Bat_Max) being function of a difference QEcH_Bat_Max ~ QECH_Bat' wherein QECH_Bat is an electrical power currently absorbed for heating the battery of the vehicle powertrain, and QEcH_Bat_Max is the value of maximum electrical power consumption by the electric heater (ECH) for heating the battery of the vehicle powertrain.

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