A method for determining a rotational speed range of a fan of a refrigeration cycle cooling circuit in a vehicle with an electric powertrain

Abstract

A method for determining a maximum speed (nFAN_Max_NVH) and a minimum speed (nFAN_Min_NVH) of a fan of a condenser of refrigeration cycle cooling circuit in a vehicle with an electric powertrain comprises: a) defining a first maximum speed limit (n FAN_Max_Batt) of the fan required for a conditioning of a battery of the vehicle; b) defining a second maximum speed limit (n FAN_Max_CabBIwr) of the fan required for a conditioning of a passenger compartment of the vehicle; c) defining a third maximum speed limit (n FAN_Max_VehMov) of the electric compressor required in case the vehicle is moving; d) defining a fourth maximum speed limit (n FAN_Max_TrcCmp) of the fan required for a conditioning of an assembly of traction components of the vehicle. In the case where the battery cooling is active, the higher from among the first limit (nFAN_Max_Batt), the second limit (nFAN_Max_CabBIwr), the third limit (nFAN_Max_VehMov) and the fourth limit (nFAN_Max_TrcCmp) is selected as the maximum fan speed (nFAN_Max_NVH), while in the case where the cooling is not active, the higher from among the second limit (nFAN_Max_CabBIwr), the third limit (nFAN_Max_VehMov) and the fourth limit (nFAN_Max_TrcCmp) is selected as the maximum fan speed (nFAN_Max_NVH). The minimum fan speed (nFAN_Min_NVH) is defined as a function of the speed of a compressor in the refrigeration cycle cooling circuit, and a vehicle moving speed.

Description

[0001] “A method for determining a rotational speed range of a fan of a refrigeration cycle cooling circuit in a vehicle with an electric powertrain”

[0002] ****

[0003] TEXT OF THE DESCRIPTION

[0004] Field of the invention

[0005] The present invention relates to vehicles with an electric powertrain, in particular to BEV-type vehicles. More specifically, the invention has been developed with reference to vehicles with an electric powertrain powered by at least one battery and comprising a refrigeration cycle cooling circuit that serves the passenger compartment of the vehicle and one or more refrigeration devices (so-called “chiller”) for the thermal conditioning of the at least one battery.

[0006] The invention is part of the subject-matter of the so-called NVH (from Noise Vibration Harshness), i.e. the optimization - among other things - of noise and vibrations, aimed at improving the comfort and performance of the vehicle.

[0007] Prior art

[0008] Vehicles with an electric powertrain (so-called BEV) are generally equipped with a refrigeration cycle cooling circuit, comprising a cabin evaporator that serves the passenger compartment of the vehicle and one or more chiller devices used for the thermal conditioning of the battery (or batteries).

[0009] The refrigeration cycle cooling circuit generally includes a condenser. The condenser is associated to both a fan and at least one radiator in heat exchange relationship with a cooling fluid flowing in a refrigerating circuit of the electric powertrain. Said fan is a source of noise and vibrations that are directly related to its rotational speed.

[0010] Given that the vehicle is driven by an extremely silent electric powertrain, the noise and vibrations generated by the fan can also be sensed by the occupants of the vehicle.

[0011] Aim of the invention

[0012] The present invention substantially aims to improve the NVH properties of a vehicle with an electric powertrain and equipped with a refrigeration cycle cooling circuit, by controlling the rotational speed of a fan that equips said circuit.

[0013] In this context, the invention aims to provide a method that allows the definition of a fan speed range that limits the sensing of noise and vibrations generated by it, but that at the same time allows the noise and vibrations of the same fan to be used to cover other noises and vibrations caused by other components of the vehicle (particularly a compressor of the refrigeration cycle circuit) that could worsen the NVH effect as a whole.

[0014] Summary of the invention

[0015] The object of the invention is achieved by a method and a vehicle having the features forming the subject-matter of the claims that follow, which form an integral part of the technical teaching provided here in relation to the invention.

[0016] Brief description of the figures

[0017] The invention will now be described with reference to the attached figures, provided purely by way of non-limiting example, in which:

[0018] - figure 1 illustrates by way of example a possible refrigeration cycle cooling circuit of a vehicle with an electric powertrain, distinguished by the application of the method according to the invention;

[0019] - figures 2-15 are schematic representations intended to exemplify possible steps of a method according to the invention,

[0020] - figure 16 is a schematic representation of some components of a vehicle with an electric powertrain, involved in the application of the method according to the invention;

[0021] - figures 17-19 are schematic representations intended to exemplify further possible steps of a method according to the invention, and

[0022] - figure 20 is a summary flowchart of a method according to the invention.

[0023] Detailed description

[0024] Figure 1 schematizes a general structure of a cooling circuit CC on which the method according to the invention can be implemented. In the following, it is assumed that the circuit under consideration equips a vehicle with at least one electric powertrain, in particular a BEV-type vehicle.

[0025] The circuit CC comprises an electrically actuated compressor EAC, whose delivery mouth is in fluid communication with the inlet of a condenser CNSD. An electrically actuated fan F is associated with the condenser CNSD in a manner known per se, as well as one or more radiators RAD in heat exchange relationship with a respective cooling fluid flowing in a cooling circuit EC of the traction components of the vehicle.

[0026] In the case exemplified in figure 1 , the traction components include at least one electric powertrain DRV with an associated suitable transmission system TRNS, to transfer the motion to the wheels of at least one axle of the vehicle. In other embodiments, the traction components may include a plurality of electric powertrains DRV, each associated to a respective wheel of the vehicle and equipped with a respective transmission system TRNS (for example including an epicyclic reduction gear). The term “powertrain DRV” as used herein is however intended to include both cases indicated and, more generally, any application in which the vehicle comprises at least one electric traction motor with an associated lubricated transmission system.

[0027] The outlet of the condenser CNDS is in fluid communication with a first circuit node N1 from which two circuit branches depart: a first branch is directed to the inlet of a cabin evaporator EVAP, to which a fan B is associated, in a manner known per se, for the environmental conditioning of the vehicle cabin; a second branch is instead directed towards the inlet of at least one refrigeration device in heat exchange relationship with a respective cooling fluid that flows in a circuit BC for cooling at least one battery BATT that powers - among other things - the powertrain DRV, through a respective inverter I NV.

[0028] In the specific case represented, said second branch of the circuit CC is directed to a second circuit node N2, in which the circuit itself forks into a third and a fourth circuit branch, directed respectively to the inlet of a first refrigeration device CHL1 , in particular a first chiller, and to the inlet of a second refrigeration device CHL2, in particular a second chiller. Note that, in other embodiments, the circuit CC could include a single chiller, or more than two chillers.

[0029] Each of the chillers CHL1 and CHL2 includes a respective battery evaporator EV_B1 , EV_B2 (which receives the refrigerant fluid flowing in the circuit CC) in heat exchange relationship with the cooling fluid flowing in said cooling circuit BC of the at least one battery BATT.

[0030] Upstream of the evaporator EVAP is an expansion / throttling valve TXV_EVAP, just as upstream of the battery evaporators of the chillers CHL1 and CHL2 are respective expansion valves TXV_CHL1 and TXV_CHL2. The expansion / evaporation valves (which in figure 1 are represented as variable hydraulic resistances) allow, by varying the respective hydraulic resistance as a function of the refrigerant flow rate (in liquid phase when passing through them), to adjust the pressure of the refrigerant fluid entering the evaporator EVAP and the battery evaporators EV_B1 , EV_B2 of the chillers CHL1 and CHL2, so as to allow complete evaporation of the refrigerant fluid inside them, thus avoiding the entry of a two-phase flow rate (liquid + vapor) to the compressor EAC. Upstream of each of the valves TXV_EVAP, TXV_CHL1 , TXV_CHL2 there are exclusion valves SV_EVAP, SV_CHL1 , SV_CHL2 respectively. The exclusion valves SV_EVAP, SV_CHL1 , SV_CHL2 can alternatively be arranged between the corresponding valve TXV_EVAP, TXV_CHL1 , TXV_CHL2 and - respectively - the cabin evaporator EVAP, the battery evaporator of the chiller CHL1 and the battery evaporator of the chiller CHL2 (in other words, it is only relevant that they are positioned upstream of, respectively, the evaporator EVAP and the battery evaporators of the chillers CHL1 and CHL2). The function of the exclusion valves SV_EVAP, SV_CHL1 , SV_CHL2, which are normally in the open position, is to exclude the circuit branch downstream of them from the circuit CC, therefore to exclude the evaporator EVAP and one or both of the battery evaporators of the chillers CHL1 and CHL2 as needed.

[0031] The outlet of chillers CHL1 and CHL2 (therefore of the battery evaporators EV_B1 , EV_B2 of the chillers CHL1 , CHL2) converges in a third circuit node N3 and in a single fifth circuit branch that converges, together with the section of the first circuit branch that starts from the outlet of the evaporator EVAP, to a fourth circuit node N4 downstream of which the cooling circuit CC closes at the intake mouth of the compressor EAC (as mentioned, the circuit CC could include a single chiller, in which case node N3 is not necessary).

[0032] In figure 1 , CU schematically represents a vehicle control unit, in which the vehicle control logic is implemented, including that for the implementation of the method according to the invention.

[0033] In a manner known per se, the compressor EAC sends into the circuit CC a total flow rate of refrigerant rriRFR_TOT in vapor phase. The flow rate rriRFR_TOT passes through the condenser CMDS in liquid phase and reaches node N1 , from which it is distributed between the evaporator EVAP (flow rate rtiRFR_cAB_EVAp) and the battery evaporators EV_B1 , EV_B2 of the chillers CHL1 and CHL2 (flow rate rtiRFR_cHL, overall entering the node N2). The flow rates rtiRFR_cAB_EVAP and riiRFR_cHL are subjected to evaporation (at substantially constant pressure) inside the battery evaporators EV_B1 , EV_B2 of the chillers CHL1 and CHL2 and the evaporator EVAP, cooling the cooling fluid of the at least one battery BATT and the cabin air, respectively. The flow rates rriRFR_cAB_EVAP and riiRFR_cHL in vapor phase are mixed at node N4 in the flow rate rriRFR_TOT, which is re-intaken by the compressor EAC to be re-introduced into the circuit CC.

[0034] As previously mentioned, the fan F is a source of noise and vibrations, which are directly related to its rotational speed, and the fact that the powertrain DRV is silent (as it is electric) can have the effect that said noise and vibrations are perceptible inside the passenger compartment of the vehicle, which it would be desirable to eliminate or reduce. On the other hand, other components of the vehicle, and in particular the compressor EAC, may be the source of noise and vibrations which, according to one aspect of the invention, may be “masked”, when needed, by the noise and vibrations generated by the fan F.

[0035] For this reason, the control method according to the invention provides for the determination of a maximum speed limit nFAN_Max_NVH of the fan F, aimed at eliminating or attenuating the sensing of noise and vibrations generated by the fan itself, and a minimum speed limit nFAN_Min_NVH, aimed at eliminating or reducing the sensing of noise and vibrations generated by other components of the vehicle.

[0036] The scheme of figure 2 provides a general overview of the control strategy implemented in accordance with the invention, according to which the identification of the maximum speed nFAN_Max_NVH for the fan F, in order to limit the noise emissions for NVH purposes, is based on the definition of: - a first maximum rotational speed limit nFAN_Max_Batt of the fan F, which depends on the amount of conditioning required for the at least one battery BATT of the vehicle;

[0037] - a second maximum rotational speed limit nFAN_Max_cabBiwr of the fan F, which depends on the amount of conditioning required for the passenger compartment of the vehicle;

[0038] - a third maximum rotational speed limit nFAN_Max_vehMov of the fan F, which depends on the vehicle moving speed; and

[0039] - a fourth maximum rotational speed limit nFAN_Max_TrccmPof the fan F, which depends on the amount of conditioning required for the traction components of the vehicle.

[0040] As will be explained below, in preferred embodiments:

[0041] - said first maximum speed limit nFAN_Max_Batt is determined on the basis of a plurality of conditions and variables, which include the temperature (Teatt) of the battery BATT, the possible existence of a charging phase (Charging Active) of the battery BATT, the speed (Vehicle_Speed) of the vehicle, the driving mode (DriveMod) selected for the vehicle, the power available (PBatt_chrg_Avi) for charging the battery BATT;

[0042] - said second maximum speed limit nFAN_Max_cabBiwr is determined on the basis of the rotational speed (ncabinBiower) of the cabin fan B of the vehicle and the ambient temperature (TAmb) outside the cabin;

[0043] - said third maximum speed limit nFAN_Max_vehMov is determined on the basis of the vehicle speed (Vehicle_Speed);

[0044] - said fourth maximum speed limit nFAN_Max_TrccmPis determined on the basis of a plurality of conditions and variables, which include the driving mode (DriveMod) selected for the vehicle, the temperature (TMO - TMO ) of the at least one motor, the temperature (Tinv_i - Tinv_4) of the related inverter and the temperature (TTmsoiM, TTmsoii_4) of the oil that lubricates the related transmission system, the temperature of the cooling fluid of the traction components (here exemplified by DRV and TRNS), at the outlet of the radiator (TRad_cint_out), at the inlet of the traction components (TTrc_cint_in) and at the outlet of the traction components (TTrc_cint_out) respectively.

[0045] Note that figure 2, as well as the subsequent figures, highlights the case of a vehicle whose powertrain includes four electric motors (Mot_1 - Mot_4), each with an associated inverter (lnv_1 - lnv_4) and a related transmission system TRNS lubricated with oil (TrsnOil_1 - TrsnOil_2). As mentioned, however, the invention is also applicable to other types of motorization, even characterized by the presence of a single electric motor with related inverter and transmission system. The minimum speed limit nFAN_Min_NVH of the fan F is preferably determined on the basis of the rotational speed of the compressor EAC (ncomp) and the vehicle moving speed (Vehicle_Speed).

[0046] A) DEFINITION OF THE MAXIMUM SPEED LIMIT

[0047] 1 ) Definition of the first maximum limit HFAN Max Batt

[0048] As shown in the diagram in figure 3, the first maximum speed limit nFAN_Max_Batt of the fan F can take two different values, depending on whether the battery BATT is being charged or not. In the first case, the limit nFAN_Max_Batt_chrg will be taken, which corresponds to a maximum speed value of the fan F that reconciles the needs of cooling of the battery in the the charging phase and compliance with an acoustic emission threshold in an NVH perspective (even in the charging phase, the battery BATT must in fact be conditioned, in order to avoid it assuming potentially dangerous temperature values). In the second case, the limit nFAN_Max_Batt_Drv will be taken.

[0049] 1.1 Definition of the limit HFAN Max Batt Drv

[0050] The definition of the limit nFAN_Max_Batt_Drv, i.e. when the battery BATT is not charging, is made on the basis of various information: a) information representative of a driving mode (DriveMod) selected for the vehicle from a plurality of possible selectable driving modes; b) information representative of a vehicle moving speed (Vehicle_Speed); c) information representative of a temperature (Teatt) of the battery (BATT), and d) information representative of a power available (PBatt_chrg_Avi) for charging the battery BATT.

[0051] The maximum limit nFAN_Max_Batt_Drv with the battery not charging is selected from a plurality of possible maximum speed limits, exemplified in the diagram in figure 4 with nFAN_Max_Batt_Drv_i , nFAN_Max_Batt_Drv_2, nFAN_Max_Batt_Drv_3, nFAN_Max_Batt_Drv_4, which are determined as a function of information representative of a driving mode selected for the vehicle, from a plurality (N) of possible selectable driving modes.

[0052] The vehicle is equipped for this purpose with a known driving mode selector (in signal communication with the control unit CU), which allows choosing between several possible modes that differ, among other things, in the type of performance offered by the powertrain DRV. In this way, it is possible to adapt the vehicle behavior to various needs, for example between a neutral or balanced driving mode, a driving mode that favors the reduction of energy consumption, an aggressive driving mode that favors sporty performance, with the latter mode which - compared to the others - is distinguished for example by a rapid and abrupt response of the accelerator, in order to make the most of the power of the powertrain DRV.

[0053] As shown in the diagram in figure 5, the limit nFAN_Max_Batt_Drv_N, corresponding to each of the “N” selectable driving modes (where in the example N is variable between 1 and 4), is in turn determined as a function of information representing the vehicle moving speed and information representing the temperature Teatt of the battery BATT. The limit nFAN_Max_Batt_Drv_N is extrapolated from a map, based on said temperature and speed.

[0054] As can be understood, and regardless of the driving mode N selected, the lower the vehicle speed, the lower the maximum rotational speed of the fan F. In qualitative terms, therefore, the speed limit of the fan F may increase as the vehicle speed increases (the aerodynamic and rolling noises dependent on the vehicle moving speed can be used to cover the noise and vibrations generated by the fan F) and as the temperature of the battery BATT increases (for safety and performance reasons).

[0055] 1 .2 Definition of the limit nFAN Max Batt chara

[0056] As mentioned, the maximum limit nFAN_Max_Batt can alternatively take the value nFAN_Max_Batt_chrg (figure 3), if the battery BATT is being charged, i.e. with the vehicle not in motion.

[0057] Also in this case, the speed limit nFAN_Max_Batt_chr is selected from at least two possible maximum speed limits, exemplified in figure 6 with nFAN_Max_Batt_Chrg_Race and nFAN_Max_Batt_Chrg_NoRace, depending On representative information of the driving mode selected for the vehicle, at least one of the first more aggressive driving mode (Race), meaning a driving mode oriented towards competitions that provides for a maximization of the exploitation of the battery BATT, and at least a second less aggressive driving mode (NoRace), meaning a driving mode oriented towards a lower exploitation of the battery BATT in the face of more prolonged and constant performance of the powertrain over time. For each possible driving mode, a related map is defined. From a qualitative point of view, the most aggressive driving mode (Race) allows higher speed limits of the fan F, since the cooling performance of the battery BATT is in this case more important than the issues of limiting noise emissions in terms of NVH; vice versa, the less aggressive driving mode (NoRace) allows lower speed limits of the fan F, since in this case the limitation of the sensing of noise and vibrations is more important.

[0058] As can be seen in figure 6, in the case in which the most aggressive driving mode (Race) is selected, the corresponding maximum speed limit nFAN_Max_Batt_chrg_Race of the fan F will be taken; otherwise, the maximum speed limit nFAN_Max_Batt_chrg_NoRace of the fan will be taken, corresponding to the selected driving mode other than the most aggressive one.

[0059] In this case, each of the possible maximum speed limits nFAN_Max_Batt_Chrg_Race OT nFAN_Max_Batt_Chrg_NoRace is in turn determined aS a function of information representative of the available power PBatt_chrg_Avi for charging the battery BATT during the charging phase and information representative of the temperature Teatt of the battery BATT.

[0060] Said available power for the battery PBatt_chrg_Avi is the maximum power that can enter the battery, and can be defined as the minimum between the maximum power that can be supplied by the charging unit (column, charging port and charging converter), the maximum power of the charger selected by the user (the user has the possibility of limiting the maximum charging power supplied by the charger), the maximum battery charging power related to the limits of the battery itself (i.e. the battery charging limit), the maximum battery charging power for limits set by the user to prevent the battery from aging.

[0061] The limit speeds for the two cases (nFAN_Max_Batt_chrg_Race and nFAN_Max_Batt_chrg_NoRace) during the charging phase of the battery BATT are extrapolated from corresponding maps based on the temperature TBatt of the battery BATT and the maximum (available) battery charging power PBatt_chrg_Avi. From a qualitative point of view, the limit speed of the fan F will increase with the increase in the available electrical power (since during the fast charging phase the available battery cooling power becomes more important, which allows the charging performance, rather than a reduction in noise emissions in terms of NVH) and with the battery temperature (for safety reasons). The fact that a map is dedicated to the most aggressive driving mode (Race) allows to increase the fast charging performance, even if at the expense of the generation of noise and vibrations. Therefore, in “ultra fast” charging conditions it is permissible to have higher noise levels than for example AC charging.

[0062] 2) Definition of the second maximum limit HFAN Max cabBiwr

[0063] The diagram in figure 7 provides a general overview of the logic used to define the maximum speed limit nFAN_Max_cabBiwr of fan F, for the purpose of reducing noise and vibrations in the case of conditioning of the vehicle cabin.

[0064] As schematized in figure 7, the definition of the second maximum rotational speed limit nFAN_Max_cabBiwr is made as a function of:

[0065] - information representative of a rotational speed ncabinBiower of the motor of the passenger compartment blower B of the vehicle,

[0066] - information representative of an ambient temperature TAmb outside the passenger compartment of the vehicle.

[0067] The maximum speed nFAN_Max_cabBiwr is extrapolated from a map based on the temperature TAmb outside the cabin and the speed ncabinBiower of the cabin fan B. From a qualitative point of view, the maximum speed limit of the fan F will increase with the increase in the speed of cabin fan B (whose operating noise is used to cover the noise and vibrations generated by fan F) and the external temperature (since as the ambient temperature increases a higher minimum performance is normally required for the purpose of conditioning in cooling the passenger compartment).

[0068] 3) Definition of the third maximum limit HFAN Max vehMov

[0069] The scheme in figure 8 provides a general overview of the control logic used for the definition of the maximum speed limit nFAN_Max_vehMov of the fan F, for the limitation of noise and vibrations in case of a moving vehicle.

[0070] As schematized in figure 8, the definition of the third maximum speed limit nFAN_Max_vehMov of the fan is carried out in function of information representative of the vehicle moving speed.

[0071] The speed limit nFAN_Max_vehMov is extrapolated from a map based on the vehicle speed. From a qualitative point of view, the maximum speed limit of the fan F will increase with increasing vehicle speed (as mentioned, the aerodynamic and rolling noises dependent on the vehicle moving speed can be exploited to cover the noise and vibrations of the fan F).

[0072] 4) Definition of the fourth maximum limit HFAN Max Trccmp

[0073] Figure 9 provides a general overview of the control logic used to define the maximum speed limit nFAN_Max_TrccmPof the fan F, for the purpose of limiting noise and vibrations, in case a conditioning of the traction components is required. As can be seen, in this case the maximum speed limit nFAN_Max_TrccmPis taken to be the higher among:

[0074] - the maximum speed npAN_Max_inv of the fan F required for the conditioning of the inverter or inverters INV,

[0075] - the maximum speed nFAN_Max_Mot of the fan F required for the conditioning of the electric motor or motors DRV,

[0076] - the maximum speed nFAN_Max_Tmsoii of the fan F required for the conditioning of the oil used for lubricating the transmission system or systems TRNS, and

[0077] - the maximum speed nFAN_Max_cint of the fan F required for the conditioning of the cooling fluid in the refrigerating circuit EC of the traction components of the vehicle.

[0078] 4.1 Definition of the limit HFAN Max inv

[0079] The scheme in figure 10 shows how the limit npAN_Max_inv from the NHV perspective corresponds to the maximum speed among those required for the conditioning of the various inverters provided. As previously indicated, in the case exemplified in the figures, the use of four motors is provided, and therefore four inverters; figure 10 therefore indicates the speeds of the fan F for each inverter: npAN_Max_inv_i , npAN_Max_inv_2, nFAN_Max_inv_3, nFAN_Max_inv_4: however, this should not be understood in a limiting sense, as only one motor, and therefore only one inverter, can also be provided.

[0080] The following figure 11 shows how the maximum speed limit nFAN_Max_inv_N, for NHV purposes, for the generic inverter N is extrapolated from a map based on the temperature Tinv_N of the inverter itself and the selected driving mode DriveMod. From a qualitative point of view, the maximum speed limit for the fan F increases with the increase in the temperature of the inverter concerned (for safety reasons), and increases from the least aggressive driving mode to the most aggressive one, given that in the case of the most aggressive mode an increase in the sensing of noise and vibrations is acceptable for performance needs.

[0081] 4.2 Definition of the limit HFAN Max Mot

[0082] Figure 12 schematically shows the logic according to which the maximum speed limit nFAN_Max_Mot of the fan F is defined, again for NHV purposes, for the conditioning of the electric motor DRV, or of each electric motor DRV.

[0083] Also in this case, the limit nFAN_Max_Mot corresponds to the maximum speed among all those required for the conditioning of the various electric motors provided; as mentioned, the figures exemplify the non-limiting case of four motors, and therefore the speeds of the fan F are indicated for each motor DRV (nFAN_Max_Mot_1 , nFAN_Max_ Mot_2, 0FAN_Max_ Mot_3, 0FAN_Max_ Mot_4).

[0084] The following figure 13 shows how the maximum speed limit nFAN_Max_Mot_N, for NHV purposes, for the generic motor N is extrapolated from a map based on the temperature TMOLN of the motor itself and the selected driving mode DriveMod. From a qualitative point of view, the maximum speed limit for the fan F increases with the increase in the temperature of the motor concerned (for safety reasons), and increases starting from the least aggressive driving mode to the most aggressive one, given that in the case of a more aggressive mode an increase in the sensing of noise and vibrations is acceptable for performance needs.

[0085] 4.3 Definition of the limit HFAN Max Trnsoii

[0086] Figure 14 schematically shows the logic according to which the maximum speed limit nFAN_Max_Tmsoii of the fan F is defined, again for NHV purposes, for the conditioning of the lubricating oil of the transmission system of each electric motor DRV.

[0087] Also in this case, the limit nFAN_Max_Tmsoii corresponds to the maximum speed of the fan F among all those required for the conditioning of the oil of the various transmission systems TRNS provided; given that the figures exemplify the non-limiting case of four motors, and therefore four related transmission systems, the speeds of the fan F for the oil of each of these transmission systems are indicated (nFAN_Max_Tmsoii_i , nFAN_Max_Tmsoii_2, nFAN_Max_TrnsOil_3, nFAN_Max_TrnsOil_4).

[0088] The following figure 15 shows how the maximum speed limit nFAN_Max_Tmsoii_N, for NHV purposes, for the oil of the generic transmission system N is extrapolated from a map based on the temperature TTmsoii_N of the oil itself and the selected driving mode DriveMod. From a qualitative point of view, the maximum speed limit for the fan F increases with the increase in the temperature of the transmission oil concerned (for safety reasons), and increases from the least aggressive driving mode to the most aggressive one, given that in the case of a more aggressive mode an increase in the sensing of noise and vibrations is acceptable for performance needs.

[0089] 4.4 Definition of the limit HFAN Max cint

[0090] Figure 16 schematically represents a part of the cooling system EC for the traction components, where it can be noted how, in preferred embodiments, the following are provided:

[0091] - a temperature sensor (TRad_cint_out) of the cooling fluid at the outlet of the radiator RAD;

[0092] - a temperature sensor (TTrc_cint_in) of the cooling fluid at the inlet of the assembly TRC of traction components (in the example including the motor DRV and the related transmission system TRNS);

[0093] - a temperature sensor (TTrc_cint_out) of the cooling fluid at the outlet of the assembly TRC of traction components.

[0094] The following figure 17 schematically represents the logic used to define the maximum speed nFAN_Max_cint of the fan F, for NHV purposes, required for the conditioning of the cooling fluid

[0095] The maximum speed nFAN_Max_cint is extrapolated from a map based on the maximum value between the values of the various temperatures of the cooling fluid detected by the sensors in figure 16, i.e. the temperature TRad_cint_out at the outlet of the radiator RAD, the temperature TTrc_cint_in at the inlet of the assembly TRC and the temperature TTrc_cint_out at the outlet of the assembly TRC. From a qualitative point of view, the maximum speed limit for the fan F increases with the increase of the maximum value of said temperatures detected by the three sensors in figure 16: this is for the safety purpose of avoiding possible boiling of the cooling fluid. Of course, the concept is applicable to positioning configurations of sensor intended to detect the various temperatures of the cooling fluid other than the one exemplified in figure 16.

[0096] Figure 18 schematically illustrates the way in which the maximum speed limit riFAN_Max_NVH of the fan F is defined, for the purpose of limiting noise and vibration, based on the various maximum speed limits as previously determined.

[0097] In accordance with the method according to the invention, once the first maximum limit nFAN_Max_Batt, the second maximum limit nFAN_Max_cabBiwr, the third maximum limit nFAN_Max_vehMov and the fourth maximum limit nFAN_Max_TrccmPhave been determined, it is verified whether a cooling phase of the battery BATT by the circuit CC is currently in progress.

[0098] As exemplified in the scheme in figure 18, in the case in which said cooling phase is active, the maximum rotational speed nFAN_Max_NVH of the fan F is taken to be the higher between the first maximum speed limit nFAN_Max_Batt, the second maximum speed limit nFAN_Max_cabBiwr, the third maximum speed limit nFAN_Max_vehMov and the fourth maximum speed limit nFAN_Max_TrcCmp-

[0099] Conversely, in the case in which said battery cooling phase is not active, the maximum rotational speed nFAN_Max_NVH of the fan F is taken to be the higher between the second maximum speed limit nFAN_Max_cabBiwr, the third maximum speed limit nFAN_Max_vehMov and the fourth maximum speed limit OFAN. _Max_TrcCmp-

[0100] Said first, second, third and fourth maximum rotational speed limits are subjected to a high update frequency (in terms of milliseconds), and therefore to a correspondingly high variability: for this reason, as shown in figure 18, it is preferable to consider the selected maximum limit as a raw datum (nFAN_Max_NVH_Raw) and subject it to a time evolution rate limitation, in order to obtain the maximum rotational speed nFAN_Max_NVH of actual interest for the control of the fan F, for the purpose of limiting noise emissions in an NVH perspective.

[0101] B) DEFINITION OF THE MINIMUM SPEED LIMIT

[0102] Figure 19 shows an overview of the control logic used for the definition of the minimum speed limit nFAN_Min_NVH of the fan F required for the limitation of noise and vibrations in an NHV perspective.

[0103] Said minimum speed limit nFAN_Min_NVH is extrapolated from a map based on the speed ncomp of the compressor EAC and the vehicle speed. From a quantitative point of view, the minimum speed value of the fan F required for NHV purposes increases: - with the increasing of the speed ncomp of the compressor EAC, since in this case the noise and vibrations generated by the fan F are exploited to cover the sensing of noise and vibrations generated by the compressor EAC, which increases with the compressor speed itself, and

[0104] - with the decreasing of the vehicle speed, since the aerodynamic and rolling noises dependent on the vehicle moving speed can be exploited to cover the noise and vibrations generated by the compressor EAC, without the need to consume additional electrical energy to operate the fan F (in the figure, the curves ncomp , ncomP_2, ncomP_3 and ncomP_4 exemplify different possible compressor speeds).

[0105] Also in this case, the minimum speed value taken is subject to temporal variability, and it is therefore preferable to take it as a raw datum (nFAN_Min_NVH_Raw), to be subjected to a limitation of the temporal evolution rate, in order to obtain the minimum speed limit nFAN_Min_NVH of actual interest for the control of the fan F for the purpose of limiting noise emissions in an NVH perspective.

[0106] The methodology of the invention is further explained in the flow chart of figure 20.

[0107] As can be seen from what is described above, the method according to the invention allows to define a maximum speed limit and a minimum speed limit of the fan such as to limit the sensing of noise and vibrations caused by the fan itself, and to exploit the noise and vibrations of the fan itself to cover other noises and vibrations caused by other components of the vehicle, particularly the compressor of its refrigeration cycle circuit, which could worsen the NVH effect as a whole, all taking into account the required performance that must in any case be ensured by the refrigeration cycle cooling circuit, depending on the possible conditions of the vehicle.

[0108] Of course, the details of construction and the embodiments may be widely varied with respect to what is described and illustrated, without thereby departing from the scope of the present invention as defined by the attached claims.

Claims

CLAIMS1. A method for determining a speed range (nFAN_Max_NVH - nFAN_Min_NVH) of a fan (F) of a refrigeration cycle cooling circuit (CC) in a vehicle with an electric powertrain (DRV), between a maximum speed (nFAN_Max_NVH) and a minimum speed (nFAN_Min_NVH), the method comprising the steps of: a) defining a first maximum speed limit (nFAN_Max_Batt) of the fan (F) required for a conditioning of at least one battery (BATT) of the vehicle; b) defining a second maximum speed limit (nFAN_Max_cabBiwr) of the fan (F) required for a conditioning of a passenger compartment of the vehicle; c) defining a third maximum speed limit (nFAN_Max_vehMov) of the fan (F) required in case the vehicle is moving; d) defining a fourth maximum speed limit (nFAN_Max_TrccmP) of the fan (F) required for a conditioning of an assembly (TRC) of traction components (DRV, TRNS) of the vehicle; e) checking whether a cooling phase of the at least one battery (BATT) is active, and e1 ) in the case where the cooling phase of the at least one battery (BATT) is active, selecting as the maximum speed (nFAN_Max_NVH) of the fan (F) the higher from among said first maximum speed limit (nFAN_Max_Batt), said second maximum speed limit (nFAN_Max_cabBiwr), said third maximum speed limit (nFAN_Max_vehMov) and said fourth maximum speed limit (nFAN_Max_TrccmP), or else e2) in the case where the cooling phase of the at least one battery (BATT) is inactive, selecting as the maximum speed (nFAN_Max_NVH) of the fan (F) the higher from among said second maximum speed limit (nFAN_Max_cabBiwr), said third maximum speed limit (nFAN_Max_vehMov) and said fourth maximum speed limit (nFAN_Max_TrccmP).

2. The method according to claim 1 , wherein the definition of the minimum speed (nFAN_Min_NVH) of the fan (F) is carried out as a function of:- information representative of a speed (ncomP) of a compressor (EAC) of the refrigeration cycle cooling circuit (CC); and- information representative of a vehicle moving speed (Vehicle_Speed).

3. The method according to claim 1 or claim 2, wherein the definition of said first maximum speed limit (nFAN_Max_Batt) is carried out on the basis of:- information representative of a driving mode (DriveMod) selected for the vehicle from a plurality of possible selectable driving modes,- information representative of a vehicle moving speed (Vehicle_Speed),- information representative of a temperature (Teatt) of the at least one battery (BATT),- information representative of a power available (PBatt_chrg_Avi) for charging the at least one battery (BATT).

4. The method according to any one of claims 1 -3, wherein the definition of said second maximum speed limit (nFAN_Max_cabBiwr) is carried out as a function of:- information representative of a rotational speed (ncabinBiower) of a motor of a passenger compartment blower (B) of the vehicle,- information representative of an ambient temperature (TAmb) outside the passenger compartment of the vehicle.

5. The method according to any one of claims 1 -4, wherein the definition of said third maximum speed limit (nFAN_Max_vehMov) is carried out as a function of information representative of a vehicle moving speed (Vehicle_Speed).

6. The method according to any one of claims 1 -5, wherein the definition of said fourth maximum speed limit (nFAN_Max_TrccmP) is carried out as a function of:- information representative of a maximum speed (nFAN_Max_inv) of the fan (F) required for a conditioning of at least one inverter (INV) associated to the at least one battery (BATT),- information representative of a maximum speed (nFAN_Max_Mot) of the fan (F) required for a conditioning of at least one electric motor belonging to the electric powertrain (DRV),- information representative of a maximum speed (nFAN_Max_Tmsoii) of the fan (F) required for a conditioning of an oil used for lubricating a transmission system (TRNS) associated to an electric motor belonging to the electric powertrain (DRV), and- information representative of a maximum speed (nFAN_Max_cint) of the fan (F) required for a conditioning of a cooling fluid of a refrigerating circuit (EC) of the assembly (TRC) of traction component (DRV, TRNS) (TRC) of the vehicle.

7. The method according to claim 1 , wherein step a) comprises selecting said first maximum speed limit (nFAN_Max_Batt) between:- a maximum speed limit (nFAN_Max_Batt_Drv) of the fan (F) required for the conditioning of the at least one battery (BATT) for the case in which the at least one battery (BATT) is not in a charging phase, or else- a maximum speed limit (nFAN_Max_Batt_chrg) of the fan (F) required for the conditioning of the at least one battery (BATT) for the case in which the at least one battery (BATT) is in a charging phase.

8. The method according to claim 7, wherein said maximum speed limit (nFAN_Max_Batt_Drv) of the fan (F) required for the conditioning of the at least one battery (BATT) for the case in which the at least one battery (BATT) is not in a charging phase is selected from a plurality of possible maximum Speed limits (nFAN.Max.Batt.Drv J nFAN_Max_Batt_Drv_2; nFAN_Max_Batt_Drv_3i nFAN_Max_Batt_Drv_4) as a function of information representative of a driving mode (DriveMod) selected for the vehicle from a plurality of possible selectable driving modes.

9. The method according to claim 8, wherein each of said possible maximum Speed limits (nFAN.Max.Batt.Drv J nFAN_Max_Batt_Drv_2; nFAN_Max_Batt_Drv_3; nFAN_Max_Batt_Drv_4) is determined as a function of information representative of a vehicle moving speed (Vehicle_Speed) and information representative of a temperature (Teatt) of the at least one battery (BATT).

10. The method according to claim 7, wherein said maximum speed limit (nFAN_Max_Batt_chrg) of the fan (F) required for the conditioning of the at least one battery (BATT) for the case in which the at least one battery (BATT) is in a charging phase, is selected from at least two possible maximum speed limits (nFAN_Max_Batt_Chrg_Racei nFAN_Max_Batt_Chrg_NoRace) aS a function of information representative of a driving mode (DriveMod) selected for the vehicle at least between a first more aggressive driving mode and a second less aggressive driving mode.

11. The method according to claim 10, wherein each of said possiblemaximum Speed limits (nFAN_Max_Batt_Chrg_Race; riFAN_Max_Batt_Chrg_NoRace) is determined as a function of information representative of a power available (PBatt_chrg_Avi) for charging the at least one battery (BATT) and information representative of a temperature (Teatt) of the at least one battery (BATT).

12. The method according to claim 6, wherein:- said information representative of a maximum speed (nFAN_Max_inv) of the fan (F) required for a conditioning of at least one inverter (INV) associated to the at least one battery (BATT) is a function of information representative of a temperature (Tinv_N) of the at least one inverter (INV) and information representative of a driving mode (DriveMod) selected for the vehicle from a plurality of possible selectable driving modes; and / or- said information representative of a maximum speed (nFAN_Max_Mot) of the fan (F) required for a conditioning of at least one electric motor belonging to the electric powertrain (DRV) is a function of information representative of a temperature (TMOLN) of the at least one electric motor and information representative of a driving mode (DriveMod) selected for the vehicle from a plurality of possible selectable driving modes; and / or- said information representative of a maximum speed (nFAN_Max_Tmsoii) of the fan (F) required for a conditioning of an oil used for lubricating a transmission system (TRNS) associated to an electric motor belonging to the electric powertrain (DRV) is a function of information representative of a temperature (TTmsoii_N) of said oil and information representative of a driving mode (DriveMod) selected for the vehicle from a plurality of possible selectable driving modes; and / or- said information representative of a maximum speed (nFAN_Max_cint) of the fan (F) required for a conditioning of a cooling fluid of a refrigerating circuit (EC) of an assembly (TRC) of traction components (DRV, TRNS) of the vehicle is a function of a maximum temperature value from:- a temperature value (TRad_cint_out) of the cooling fluid at the outlet of a radiator (RAD) associated to the fan (F),- a temperature value (TTrc_cint_in) of the cooling fluid at the inlet of the assembly (TRC) of traction components (DRV, TRNS), and- a temperature value (TTrc_cint_out) of the cooling fluid at the outlet of the assembly (TRC) of traction components (DRV, TRNS).

13. The method according to claim 1 , wherein- the higher from among said first maximum speed limit (nFAN_Max_Batt), said second maximum speed limit (nFAN_Max_cabBiwr), said third maximum speed limit (nFAN_Max_vehMov) and said fourth maximum speed limit (nFAN_Max_TrcCmp), OT else- the higher from among said second maximum speed limit (nFAN_Max_cabBiwr), said third maximum speed limit (nFAN_Max_vehMov) and said fourth maximum speed limit (nFAN_Max_TrccmP), is a raw datum (nFAN_Max_NVH_Raw) that is subject to a time evolution rate limitation to determine said maximum speed (nFAN_Max_NVH) of the fan (F).

14. The method according to claim 2, wherein said minimum speed (nFAN_Min_NVH) of the fan (F) is obtained by subjecting to a time evolution rate limitation a raw datum (nFAN_Min_NVH_Raw) defined as a function of said information representative of a speed (ncomp) of the compressor (EAC) and said information representative of a vehicle moving speed (Vehicle_Speed).

15. A vehicle having an electric powertrain (DRV), at least one battery (BATT) and a refrigeration cycle cooling circuit (CC) that includes an electric compressor (EAC) and a fan (F), the vehicle having a control unit (CU) with associated memory means in which a computer product is stored to implement the method according to one or more of claims 1 -14.

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