Heating system for a motor vehicle

Abstract

The invention relates to a heating system (50) for a motor vehicle (1), comprising an electronic control unit (53), a primary circuit (51) and a secondary circuit (52) through which a heat transfer fluid flows, the primary circuit (51) comprising a main pump (512), a heat exchanger of the electric machine (514), an air conditioning heat exchanger (516), the secondary circuit (52) comprising a secondary pump (522), a heat exchanger of the electric battery (526), a three-way valve (521) of which one inlet (521-A) is connected to the primary circuit (51), another inlet (521-B) is connected to the heat exchanger of the electric battery (526), and the outlet (521-C) is connected to the inlet of the secondary pump (522), the electronic control unit (53) controlling the performance of the electric machine (30) and the opening of the three-way valve (521) so as to ensure the heating of the air conditioning and of the electric battery (40).

Description

DESCRIPTION Automotive heating system [Technical field]

[0001] The present invention relates to the field of electric or hybrid motor vehicles and more particularly concerns a heating system. [Prior art]

[0002] Motor vehicles include a cabin temperature control system, which regulates the temperature inside the passenger compartment, where the driver and passengers are located. In low outside temperatures, this system heats the cabin.

[0003] Classically, this system corresponds to an air conditioning system in which air, coming from outside the vehicle and / or being recycled from the passenger compartment itself, is heated, then ventilated inside the passenger compartment in a heating configuration.

[0004] One solution is to use heating elements powered by an electric battery to heat the air circulating in the air conditioning system. However, this solution results in higher current consumption from the electric battery, which therefore needs to be recharged more frequently. This disadvantage is particularly pronounced for electric or hybrid vehicles, where the battery also powers the electric motor that provides the vehicle's torque.

[0005] Another solution, particularly advantageous for electric or hybrid motor vehicles, consists of heating the air by a heat exchanger, known as an "air conditioning" exchanger, placed in the airflow of the air conditioning system and in which a heat transfer fluid circulates.

[0006] The air conditioning heat exchanger is part of a primary circuit comprising a main pump and passing through a heat exchanger, called an "electric machine" heat exchanger, configured to carry out heat exchanges between the heat transfer fluid and the electric machine that provides the vehicle's motorization.

[0007] Thus, the heat transfer fluid cools the electric machine as it passes through the electric machine's heat exchanger, and then heats the air circulating in the air conditioning system as it passes through the air conditioning heat exchanger. The heat transfer fluid exits the air conditioning heat exchanger cooled and can therefore cool the electric machine in another cycle.

[0008] This solution has the advantage of not directly causing electrical consumption from the charging of the vehicle's electric battery.

[0009] However, the electric battery temperature must also be regulated. Indeed, temperatures that are too high or too low can lead to increased energy consumption and heightened safety risks. It may also be necessary to maintain the electric battery at a specific temperature when the vehicle is charging, particularly for fast charging.

[0010] In conditions of low outside temperatures, it is therefore necessary to ensure that the electric battery is kept at the correct temperature, as with the passenger compartment.

[0011] One solution is to use a secondary circuit, comprising a secondary pump, a heating module, and a heat exchanger for the electric battery. The heat transfer fluid in the secondary circuit is circulated by the secondary pump and then heated by the heating module. As it passes through the electric battery heat exchanger, the heat transfer fluid maintains the electric battery's temperature.

[0012] This solution allows for separate control of the cabin air conditioning temperature and the electric battery temperature. However, this solution results in significant bulk due to the number of components required for the two cooling circuits. The combined energy consumption is also substantial.

[0013] Furthermore, the heat recovered by the electric machine's heat transfer fluid may not be sufficient to heat the air conditioning unit according to the user's command. A heating module, for example powered by the electric battery, is then required, which increases the unit's size and battery consumption.

[0014] One solution could be to place the electric battery heat exchanger in the primary circuit, either upstream or downstream of the electric machine's heat exchanger. However, in this configuration, it is not possible to control the air conditioning temperature and the electric battery temperature separately. Furthermore, the electric machine's heat losses might be insufficient to simultaneously regulate the battery temperature and heat the air for the air conditioning.

[0015] Therefore, there is a need for a simple and effective solution to remedy at least some of these drawbacks. [Description of the invention]

[0016] To this end, the invention first relates to a heating method for a motor vehicle, in particular for a hybrid or electric vehicle, said vehicle comprising an air conditioning system, an electric machine and an electric battery configured to supply electricity to said electric machine, and a heating system comprising an electronic control unit, a primary circuit in which a heat transfer fluid circulates and comprising in one direction of circulation of the heat transfer fluid:

[0017] - a main pump controlled by said electronic control unit, said main pump being configured to circulate the heat transfer fluid in the primary circuit at a flow rate controlled by the electronic control unit,

[0018] - a heat exchanger, referred to as the "electrical machine" heat exchanger, configured to perform heat exchanges between the heat transfer fluid and the electrical machine,

[0019] - a temperature sensor positioned at the outlet of the heat exchanger of the electric machine,

[0020] - an air conditioning heat exchanger configured to perform heat exchange between the heat transfer fluid and the air circulating in the air conditioning system,

[0021] - a temperature sensor positioned at the inlet of the air conditioning heat exchanger,

[0022] and a secondary circuit in which a heat transfer fluid circulates and comprising, in one direction of heat transfer fluid circulation:

[0023] - a secondary pump controlled by the electronic control unit, said secondary pump being configured to circulate the heat transfer fluid in the secondary circuit at a flow rate controlled by the electronic control unit,

[0024] - a heat exchanger known as the "electric battery" heat exchanger, configured to perform heat exchanges between the heat transfer fluid and the electric battery,

[0025] - a temperature sensor positioned at the inlet of the electric battery's heat exchanger,

[0026] - a three-way valve, one inlet of which is connected to the primary circuit between the heat exchanger of the electric machine and the air conditioning heat exchanger, another inlet is connected to the outlet of the heat exchanger of the electric battery in the direction of circulation of the heat transfer fluid, and the outlet of the three-way valve is connected to the inlet of the secondary pump,

[0027] said electronic control unit being configured to control the performance of the electrical machine and the opening of the three-way valve, as well as to receive measurements from the temperature sensors, said method comprising the steps of:

[0028] - calculation, by the electronic control unit, of the heat exchanges necessary to heat the air circulating in said air conditioning system and to heat the electric battery to target temperatures,

[0029] - calculation, by the electronic control unit, of the maximum power that the electrical machine can provide through heat dissipation to reach the target temperatures,

[0030] - sending a command, via the electronic control unit, to the electrical machine to degrade its performance in order to generate a power equal to the calculated power,

[0031] - calculation, by the electronic control unit, of the volumetric flow rate of the heat transfer fluid in the primary circuit necessary to carry out heat exchange for the air circulating in the air conditioning system,

[0032] - Adjustment of the main pump's flow rate to ensure the calculated volumetric flow rate in the primary circuit.

[0033] - determination, by the electronic control unit, of the thermal power available to heat the electric battery,

[0034] - calculation, by the electronic control unit, of the volumetric flow rate of the heat transfer fluid in the secondary circuit necessary to carry out the heat exchanges with the electric battery,

[0035] - Adjusting the secondary pump flow rate to ensure the calculated volumetric flow rate in the secondary circuit,

[0036] - calculation, by the electronic control unit, of the position of the three-way valve,

[0037] - setting the three-way valve to the calculated position.

[0038] The heating process according to the invention thus makes it possible to heat the air circulating in the air conditioning system as well as the electric battery under low outside temperature conditions, using the heat losses of the electric motor. The heating process therefore does not require a separate heating module for the secondary circuit, resulting in a more compact and self-contained heating system. The air conditioning system also does not require an additional heating stage. The three-way valve allows the process to independently manage the temperature control of the air conditioning and the electric battery while using only a single heat transfer fluid circuit, thus saving space and components within the vehicle.

[0039] Advantageously, the electronic control unit can receive a pre-registration for heating or air conditioning, and the calculation of the necessary heat exchange only considers the heat exchange within the air conditioning unit if the heating or air conditioning command is received. This heating process thus prioritizes cabin air conditioning and the comfort of the occupants and driver.

[0040] Preferably, the flow rate setting of the main and / or secondary pump is performed using a pre-recorded lookup table that links the expected volumetric flow rate in the primary and / or secondary circuit to the operating speed of the main and / or secondary pump. This table can be established empirically during vehicle calibration tests and stored in a memory area of ​​the electronic control unit.

[0041] In a preferred embodiment of the invention, the calculation of the three-way valve position is performed using a pre-recorded lookup table between the volumetric flow rate in the primary circuit and the volumetric flow rate in the secondary circuit. This table can be established empirically during vehicle calibration tests and stored in a memory area of ​​the electronic control unit.

[0042] Advantageously, in this embodiment, the step of determining and adjusting the position of the three-way valve includes a substep of iteratively determining the position of the three-way valve based on measurements of the volumetric flow rate entering the primary circuit and the volumetric flow rate in the secondary circuit. This determination allows for a first step that quickly and easily adjusts the three-way valve, and a finer, closed-loop adjustment step that prevents oscillations in volumetric flow rate and temperature due to feedback loops in the secondary circuit.

[0043] The invention also relates to an electronic control unit for a motor vehicle heating system, said vehicle comprising an air conditioning system, an electric machine and an electric battery configured to supply electricity to said electric machine, said heating system comprising a main pump, a secondary pump, an air conditioning heat exchanger and an electric battery heat exchanger, a three-way valve and a plurality of temperature sensors, said electronic control unit being configured to:

[0044] - be connected to said main pump and said secondary pump and control the volumetric flow rates of the main pump and the secondary pump,

[0045] - be connected to said three-way valve and control the configuration of the opening of the three-way valve,

[0046] - to monitor the performance of the electrical machine,

[0047] - be connected to a plurality of temperature sensors and receive the temperature measurements taken by said temperature sensors,

[0048] - calculate the heat exchanges required to reach a target temperature in said air conditioning heat exchanger and in said electric battery heat exchanger.

[0049] Preferably, in an embodiment where the vehicle includes an inverter connected to the electric machine, the electronic control unit is further configured to be connected to said inverter to control the inverter's performance. The inverter is a device that drives the alternating current that powers the electric machine and requires cooling through heat exchange with the heat transfer fluid. Therefore, the inverter can also heat the heat transfer fluid, possibly resulting in a degradation of its performance.

[0050] The invention also relates to a heating system for a motor vehicle, in particular for a hybrid or electric vehicle, said vehicle comprising an air conditioning system, an electric machine and an electric battery configured to supply electricity to said electric machine, said heating system comprising an electronic control unit as shown, a primary circuit in which a heat transfer fluid circulates and comprising in one direction of circulation of the heat transfer fluid:

[0051] - a main pump controlled by said electronic control unit, said main pump being configured to circulate the heat transfer fluid in the primary circuit at a flow rate controlled by the electronic control unit,

[0052] - a heat exchanger, referred to as the "electrical machine" heat exchanger, configured to perform heat exchanges between the heat transfer fluid and the electrical machine,

[0053] - an air conditioning heat exchanger configured to perform heat exchange between the heat transfer fluid and the air circulating in the air conditioning system,

[0054] and a secondary circuit in which a heat transfer fluid circulates and comprising, in one direction of heat transfer fluid circulation:

[0055] - a secondary pump controlled by the electronic control unit, said secondary pump being configured to circulate the heat transfer fluid in the secondary circuit at a flow rate controlled by the electronic control unit,

[0056] - a heat exchanger known as the "electric battery" heat exchanger, configured to perform heat exchanges between the heat transfer fluid and the electric battery,

[0057] - a three-way valve, one inlet of which is connected to the primary circuit between the heat exchanger of the electric machine and the air conditioning heat exchanger, another inlet is connected to the outlet of the heat exchanger of the electric battery in the direction of circulation of the heat transfer fluid and the outlet of the three-way valve is connected to the inlet of the secondary pump.

[0058] The heating system according to the invention thus makes it possible to implement the heating process according to the invention.

[0059] Preferably, in the embodiment where the vehicle includes an inverter connected to the electric machine, the primary circuit of the heating system includes an inverter heat exchanger upstream of the electric machine heat exchanger, said inverter heat exchanger being configured to perform heat exchange between the heat transfer fluid and the inverter. The inverter is a device that controls the alternating current that powers the electric machine and requires cooling through heat exchange with the heat transfer fluid. The heating system can thus recover heat from the inverter, which is necessarily present in electric or hybrid vehicles.

[0060] Advantageously, in this embodiment, the vehicle includes a charger in addition to the inverter, connected to the electric motor, and the primary circuit includes a charger heat exchanger upstream of the electric motor heat exchanger. This charger heat exchanger is configured to perform heat exchange between the heat transfer fluid and the charger. The heating system can thus recover heat from the charger, which is necessary in an electric vehicle but optional for a hybrid vehicle.

[0061] According to another aspect, the invention also relates to a motor vehicle, in particular a hybrid or electric vehicle, comprising an air conditioning system, an electric machine, an electric battery configured to supply electricity to said electric machine and a heating system as shown. [Description of the drawings]

[0062] Other features and advantages of the invention will become apparent upon reading the following description. This description is purely illustrative and should be read in conjunction with the accompanying drawings, in which:

[0063] [Fig 1] Figure 1 schematically illustrates a motor vehicle comprising a heating system according to the invention.

[0064] [Fig 2] Figure 2 schematically illustrates the primary circuit of the heating system according to the prior art.

[0065] [Fig 3] Figure 3 schematically illustrates the secondary circuit of the heating system according to the prior art.

[0066] [Fig 4] Figure 4 schematically illustrates one embodiment of the heating system according to the invention, comprising the primary circuit and the secondary circuit.

[0067] [Fig 5] Figure 5 schematically illustrates the operation of the three-way valve of the heating system according to the invention.

[0068] [Fig 6] Figure 6 schematically illustrates the sequence of the heating process according to the invention. [Description of the embodiments]

[0069] Figure 1 schematically illustrates an example of an electric automobile vehicle according to the invention.

[0070] Vehicle 1 includes a heating system 50 which allows heating of the passenger compartment 10 and the electric battery 40 of said vehicle 1.

[0071] Vehicle 1

[0072] As shown in Figure 1, vehicle 1 is an electric or hybrid vehicle comprising a passenger compartment 10, an air conditioning system 20, an electric machine 30, an electric battery 40, and a heating system 50.

[0073] The passenger compartment 10 is the space in which the passengers and driver of vehicle 1 are seated when they are travelling in vehicle 1.

[0074] To ensure passenger comfort, and in particular to ensure heating of the passenger compartment 10 for low outside temperatures, the passenger compartment 10 is connected to the air conditioning system 20.

[0075] The air conditioning system 20 draws in air from outside and / or recycles the air already contained in the passenger compartment 10 and heats it, then blows it into the passenger compartment 10.

[0076] The electric motor 30 provides torque to the wheels of vehicle 1 to enable its movement. The electric motor 30 is powered by the electric battery 40.

[0077] Vehicle 1 also includes an inverter 30-1 and a charger 30-2 between the electric machine 30 and the electric battery 40. For clarity, the inverter 30-1 and the charger 30-2 are not shown in Figure 1.

[0078] Heating system 50

[0079] The heating system 50 heats the air circulating in the air conditioning system 20 and heats the electric battery 40.

[0080] As shown in Figures 2 to 4, the heating system 50 comprises a primary circuit 51, a secondary circuit 52 and at least one electronic control unit 53, 54.

[0081] Primary circuit 51

[0082] The primary circuit 51 is a fluid circuit comprising a heat transfer fluid configured to heat the air circulating in the air conditioning system 20 and controlled by the electronic control unit 53.

[0083] The heat transfer fluid circulating in the primary circuit 51 can be water, glycerin, or a mixture of water and glycerin. The heat transfer fluid has a coefficient Cp called the specific heat capacity, which corresponds to the fluid's ability to store energy when heated.

[0084] The embodiment of the primary circuit 51 described in the prior art is shown in Figure 2. The primary circuit 51 includes, in the direction of circulation of the heat transfer fluid, a main pump 512, a heat exchanger of the electrical machine 514 and an air conditioning heat exchanger 516.

[0085] In this embodiment, the primary circuit 51 also includes an inverter heat exchanger 513-A and a charger heat exchanger 513-B located between the main pump 512 and the electrical machine heat exchanger 514.

[0086] The heat exchanger of the 513-A inverter performs heat exchanges between the heat transfer fluid and the 30-1 inverter.

[0087] The heat exchanger of the 513-B charger performs heat exchanges between the heat transfer fluid and the 30-2 charger.

[0088] In this embodiment, the electronic control unit 53 is connected to the main pump 512 and the flow control to impose a volumetric flow rate Qm,1 in the primary circuit 51. The electronic control unit 53 also controls the air conditioning system 20 to be able to heat the air more if the heat supplied by the heat exchanges in the air conditioning heat exchanger 516 is not sufficient to ensure a user air conditioning control.

[0089] The embodiment of the primary circuit 51 according to the invention is shown in Figure 4. The primary circuit 51 comprises, in the direction of circulation of the heat transfer fluid, a main pump 512, a heat exchanger of the electric machine 514, a temperature sensor 515 at the outlet of the heat exchanger of the electric machine 514, an air conditioning heat exchanger 516 and a temperature sensor 517 at the inlet of the air conditioning heat exchanger 516.

[0090] In this embodiment, the electronic control unit 53 is connected to the main pump 512 and the flow control to impose a volumetric flow rate Qm, 1 in the primary circuit 51. The electronic control unit 53 is also connected to the temperature sensor 515 and the temperature sensor 517 and is configured to receive the temperature values ​​measured by these two sensors 515, 517.

[0091] The temperature sensor 515 is located at the outlet of the heat exchanger of the electric machine 514 and measures the TEM temperature of the heat transfer fluid at that point.

[0092] The temperature sensor 517 is located at the inlet of the air conditioning heat exchanger 516 and measures the temperature TCIim of the heat transfer fluid at that point.

[0093] In this embodiment, the electronic control unit 53 is not connected to the air conditioning system 20, but is connected to the electrical machine 30 to control its performance.

[0094] The electronic control unit 53 is also connected to the inverter 30-1. For clarity, the electronic link is not shown in the figures.

[0095] In this embodiment of the primary circuit 51 according to the invention, the primary circuit 51 also includes an inverter heat exchanger 513-A and a charger heat exchanger 513-B located between the main pump 512 and the electric machine heat exchanger 514.

[0096] Secondary circuit 52

[0097] The secondary circuit 52 is a fluid circuit comprising a heat transfer fluid configured to heat the electric battery 40.

[0098] The heat transfer fluid circulating in the secondary circuit 52 can be water, glycerin, or a mixture of water and glycerin. The heat transfer fluid has a coefficient Cp, called the specific heat capacity, which corresponds to the fluid's ability to store energy when heated.

[0099] The embodiment of the secondary circuit 52 described in the prior art is shown in Figure 3. The secondary circuit 52 includes, in the direction of circulation of the heat transfer fluid, a secondary pump 522, a heating module 524 and a heat exchanger for the electric battery 526.

[0100] In this embodiment, the electronic control unit 54 is connected to the secondary pump 522 and the flow control to impose a volumetric flow rate Qm,2 in the secondary circuit 52.

[0101] The electronic control unit 54 also controls the heating module 524 in order to heat the heat transfer fluid to warm the electric battery 40.

[0102] The heat exchanger of the electric battery 526 performs heat exchanges between the heat transfer fluid thus heated by the heating module 524 and the electric battery 40.

[0103] The embodiment of the secondary circuit 52 according to the invention is shown in Figure 4. The secondary circuit 52 comprises, in the direction of circulation of the heat transfer fluid, a three-way valve 521, a secondary pump 522, a temperature sensor 525 and a heat exchanger for the electric battery 526.

[0104] In this embodiment, the heat transfer fluid circulating in the primary circuit 51 and secondary circuit 52 is the same heat transfer fluid. The primary circuit 51 and the secondary circuit 52 are fluidically connected.

[0105] As shown in Figures 4 and 5, the three-way valve 521 comprises two inlets, 521-A and 521-B, and one outlet, 521-C. Inlet 521-A is connected to the primary circuit 51 between the heat exchanger of the electric machine 514 and the air conditioning heat exchanger 516. Inlet 521-B is connected to the outlet of the electric battery heat exchanger 526 in the direction of heat transfer fluid flow. Outlet 521-C of the three-way valve 521 is connected to the inlet of the secondary pump 522.

[0106] The volumetric flow rate at the inlet 521-A is noted Qm,A, the volumetric flow rate at the inlet 521-B is noted Qm,B and the volumetric flow rate at the outlet 521-C is noted Qm,C.

[0107] The three-way valve 521 has an internal position that can be adjusted according to the desired volumetric flow rates Qm,A, Qm,B, and Qm,C. Specifically, knowing the inlet flow rates Qm,A and Qm,B and the outlet flow rate Qm,C, it is possible to determine the required opening of the three-way valve 521 using theoretical considerations or empirical tables.

[0108] The temperature sensor 525 is located at the inlet of the electric battery heat exchanger 526 and measures the temperature TBat of the heat transfer fluid at that point.

[0109] The secondary circuit 52 is also connected upstream of the inlet 521-B to the primary circuit 51 between the air conditioning heat exchanger 516 and the connection between the primary circuit 51 and the inlet 521-A of the three-way valve 521. The flow rate circulating in this connection is noted Qm,R.

[0110] Due to the conservation of mass of the heat transfer fluid circulating in the heating system 50, the volumetric flow rate Qm,R is equal to the volumetric flow rate Qm,A.

[0111] In the embodiment shown in Figure 4, the electronic control unit 53 is configured to control the performance of the electric machine 30. In particular, the electronic control unit 53 can force the electric machine 30 to degrade its performance while ensuring the electrical supply of the vehicle 1 to generate heat.

[0112] Advantageously, the electronic control unit 53 can also control the performance of the inverter 30-1 in order to generate heat in the same way.

[0113] The electronic control unit 53 is configured to control the flow rate of the main pump 512 and the secondary pump 522. Preferably, the electronic control unit 53 contains a lookup table between the volumetric flow rate and the pump speed to control a pump speed corresponding to the required flow rate.

[0114] The electronic control unit 53 includes a table for the main pump 512 and a table for the secondary pump 522.

[0115] The electronic control unit 53 is configured to receive temperature values ​​measured by temperature sensors 515, 517 and 525.

[0116] The electronic control unit 53 is configured to control the internal position of the three-way valve 521. Preferably, the electronic control unit 53 is configured to calculate the internal position of the three-way valve 521 to obtain the flow rate Qm,C from pre-established flow rates Qm,A and Qm,B.

[0117] Preferably, the electronic control unit 53 includes a pre-established empirically determined table including the required opening for each required Qm,A, Qm,C pair.

[0118] Example of implementation

[0119] When the vehicle 1 is operating in low outside temperature conditions, the electronic control unit 53 implements the process according to the invention in order to control the temperature of the electric battery 40 and that of the air circulating in the air conditioning system 20 and in the passenger compartment 10 according to target values.

[0120] For example, the target value of the temperature of the electric battery 40 may be a value imposed by the manufacturer for safety reasons and for the proper functioning of said electric battery 40. The target value of the temperature of the passenger compartment 10 may be set manually by the driver or by one of the passengers present in the passenger compartment 10 of the vehicle.

[0121] In a first step E1, the electronic control unit 53 calculates the heat exchanges that are required at the level of the air conditioning heat exchanger 516 and at the level of the electric battery heat exchanger 526 to heat the air circulating in the air conditioning system 20 and the electric battery 40 from their temperature at the present time to that corresponding to the target values.

[0122] The sum of these heat exchanges gives the total theoretical power PTot,C that the heating system 50 must recover from the heat exchanges at the level of the heat exchanger of the electrical machine 514.

[0123] The calculated theoretical power PTot,C is therefore the sum of the power PCIim.C required to heat the air circulating in the air conditioning system 20 to the target temperature, and the power PBat,C required to heat the electric battery 40:

[0124] [Math 1]

[0125] Prot,c = Pcum,c + Peat,c

[0126] In this step, the electronic control unit 53 calculates a target value TCIim.C of the temperature of the heat transfer fluid at the inlet of the air conditioning heat exchanger 516 and a target value TBat.C of the temperature of the heat transfer fluid at the inlet of the electric battery heat exchanger 526.

[0127] In a second step E2, the electronic control unit 53 calculates the maximum power PEM.max that the electrical machine 30 can provide by thermal dissipation and compares it with the total theoretical calculated power PTot.C.

[0128] The aim is to degrade the performance of the electric machine 30 in order to cause heat losses which will heat the heat transfer fluid.

[0129] In addition, the electronic control unit 53 calculates the power that the inverter 30-1 can provide through thermal dissipation.

[0130] If the calculated theoretical total power is less than the maximum power that the electric machine 30 can supply, the electronic control unit 53 sends a command in a performance stage E3 to the electric machine 30 to degrade its performance so as to generate a power Pg equal to the theoretical total power required.

[0131] If the total theoretical calculated power is greater than the maximum power that the machine can supply, the electronic control unit 53 sends a performance command to the electric machine 30 in step E3 to degrade its performance in order to generate the maximum power that the electric machine 30 can supply by thermal dissipation.

[0132] The electronic control unit 53 therefore sends a performance command so that the electrical machine 30 generates a power Pg, given by the formula:

[0133] [Math 2]

[0134] Pg min(ff O f £, PEM max)

[0135] In a step E4, the electronic control unit 53 calculates the volumetric flow rate Qm,1 of the heat transfer fluid in the primary circuit 51 required to carry out the heat exchanges to reheat the heat transfer fluid with the heat losses generated by the degradation of the performance of the electric machine 30, then converts this volumetric flow rate Qm,1 into a speed control of the main pump mechanism 512.

[0136] The calculation of the flow rate Qm,1 from the power generated Pg by the electric machine 30 involves the specific heat capacity Cp of the heat transfer fluid and the difference (AT)Clim between the value of the temperature TCIim measured at the inlet of the air conditioning heat exchanger 516 by the temperature sensor 517 and the target temperature value TCIim, C.

[0137] [Math 3] [L0138] JQV m , l = - C p (&T) - clm

[0139] In a step E5, the main pump 512 receives the speed command sent from the electronic control unit 53 and imposes the determined volumetric flow rate Qm,1 in the primary circuit 51.

[0140] In a step E6, the electronic control unit 53 determines the proportion of heat exchanges that are available to heat the electric battery 40.

[0141] Preferably, the heating system 50 primarily heats the air circulating in the air conditioning system 20, and therefore the power available to heat the electric battery 40 is the remaining power.

[0142] Therefore, in step E6, if the heating of the passenger compartment 10 is requested by the users of vehicle 1, the thermal power available to the electric battery 40 is proportional to the difference between the measured temperature TEM at the outlet of the heat exchanger of the electric machine 514 and the target temperature TCIim.C at the inlet of the air conditioning heat exchanger 516:

[0143] [Math 4]

[0144] (AT) Bat = T EM — T C u m C

[0145] If heating is not required, the thermal power available for the electric battery 40 depends on the target temperature TBat,C for the electric battery 40 and the temperature T,EM at the outlet of the heat exchanger of the electric machine 514.

[0146] Indeed, if the measured temperature TEM at the outlet of the heat exchanger of the electric machine 514 is greater than the target temperature TBat,C at the inlet of the heat exchanger of the electric battery 526, the heating system 50 can ensure the heating setpoint of the electric battery 40, and therefore the thermal power required to heat the electric battery 40 is proportional to the temperature difference between the measured temperature TBat and the target temperature TBat,C at the inlet of the heat exchanger of the electric battery 526.

[0147] On the other hand, if the measured temperature TEM at the outlet of the heat exchanger of the electric machine 514 is lower than the target temperature TBat.C at the inlet of the heat exchanger of the electric battery 526, the heating system 50 cannot ensure the heating setpoint of the electric battery 40 in full since there is no additional heating module between the heat exchanger of the electric machine 514 and the heat exchanger of the electric battery 526 which would allow to heat the heat transfer fluid more.

[0148] In this case, the thermal power available to heat the electric battery 40 is therefore proportional to the difference between the measured temperature TEM at the outlet of the heat exchanger of the electric machine 514 and the target temperature TBat.C at the inlet of the heat exchanger of the electric battery 526. The heating of the electric battery 40 is achieved partially.

[0149] Thus, when heating is not required, the thermal power available to the electric battery is proportional to the temperature difference given by the following formula:

[0150] [Math 5]

[0151] (AT) Bat = min(T m BM — T cBat ') — T mBat

[0152] The available thermal power PBat is therefore calculated from the volumetric flow rate Qm, 1 in the primary circuit 51, the specific heat capacity Cp of the heat transfer fluid and the difference (AT)Bat:

[0153] [Math 6]

[0154] P Bat = Q m l C p (CT) Bat

[0155] In step E7, the electronic control unit 53 calculates the volumetric flow rate Qm,2 of the heat transfer fluid in the secondary circuit 52 required to perform the heat exchange necessary to heat the electric battery 40 with the remaining power. This volumetric flow rate Qm,2 is a speed control for the secondary pump mechanism 522.

[0156] The calculation of the volumetric flow rate Qm,2 from the power available for the battery PBat involves the specific heat capacity Cp of the heat transfer fluid and the difference (AT)Bat.

[0157] [Math 7]

[0159] In a step E8, the secondary pump 522 receives the speed command sent by the electronic control unit 53 and imposes the volumetric flow rate Qm,2 determined in the secondary circuit 52.

[0160] The volumetric flow rate Qm,C at the outlet of the three-way valve 521 is therefore equal to the volumetric flow rate Qm,2 imposed by the secondary pump 522.

[0161] In a step E9, the electronic control unit 53 calculates the position of the three-way valve 521 in order to regulate the contribution Qm,A of the volumetric flow rate from the primary circuit 51 to the volumetric flow rate Qm,2 of the secondary circuit 52 imposed by the secondary pump 522 and that of the volumetric flow rate Qm,B recovered from the secondary circuit 52.

[0162] The connection between the upstream of the inlet 521-B of the three-way valve 521 and the upstream of the air conditioning heat exchanger 516 ensures that the heat transfer fluid of the secondary circuit 52 which does not enter the three-way valve 521 returns to the primary circuit 51, ensuring that the volumetric flow rate circulating in the air conditioning heat exchanger 516 is indeed the volumetric flow rate Qm,1 imposed by the main pump 512.

[0163] This step is carried out in two sub-steps.

[0164] In a first sub-step, the volumetric flow rate Qm,A taken from the primary circuit 51 is calculated from the thermal power to be supplied to the electric battery 40 from the heat exchanger of the electric machine 514 and the determined target temperatures. From this volumetric flow rate Qm,A and the volumetric flow rate Qm,2 imposed by the secondary pump 522 at the outlet 521-C of the three-way valve 521, the electronic control unit 53 calculates the opening of the three-way valve 521 for the return of heat transfer fluid from the secondary circuit 52 to the inlet 521-B, respecting the conservation of mass:

[0165] [Math 8]

[0166] Q mi B = Qm,2 ~ Qm,A

[0167] The determination of the opening is carried out from a table included in the memory area of ​​the electronic control unit 53, comprising the opening corresponding to each required Qm,A, Qm,C pair.

[0168] In a second sub-step, an iterative loop is calculated by the electronic control unit 53 in order to fine-tune the flow rate and avoid oscillations of the initial volume due to loop effects and therefore temperature oscillations.

[0169] The electronic control unit 53 also takes into account the limits of the heating system 50. If the volumetric flow rate Qm,A calculated at the inlet 521-A of the three-way valve 521 is greater than or equal to the volumetric flow rate Qm,2 imposed by the secondary pump 522, the equation is no longer attainable and therefore the electronic control unit 53 closes the inlet 521-B of the three-way valve 521.

[0170] The heating system 50 according to the invention thus provides heating for the air passing through the air conditioning system 20 to regulate the temperature inside the passenger compartment 10, as well as maintaining the temperature of the electric battery 40 by recovering and generating heat losses in the electric motor 30 to heat a heat transfer fluid. The primary circuit 51 and the secondary circuit 52 are thus connected, which reduces the number of components in the heating system 50. The three-way valve 521 allows for more independent regulation of the heating of the air circulating in the air conditioning system 20 and that of the electric battery 40, giving priority to the air conditioning of the passenger compartment 10.

Claims

Demands

1. A heating method for a motor vehicle (1), in particular for a hybrid or electric vehicle, said vehicle (1) comprising an air conditioning system (20), an electric machine (30) and an electric battery (40) configured to supply electricity to said electric machine (30), and a heating system (50) comprising an electronic control unit (53), a primary circuit (51) in which a heat transfer fluid circulates and comprising, in one direction of circulation of the heat transfer fluid: a main pump (512) controlled by said electronic control unit (53), said main pump (512) being configured to circulate the heat transfer fluid in the primary circuit (51) at a flow rate (Qm,1) controlled by the electronic control unit (53), a heat exchanger called "of the electrical machine" (514) configured to carry out heat exchanges between the heat transfer fluid and the electrical machine (30), a temperature sensor (515) positioned at the outlet of the heat exchanger of the electrical machine (514), an air conditioning heat exchanger (516) configured to perform heat exchanges between the heat transfer fluid and air circulating in the air conditioning system (20), a temperature sensor (517) positioned at the inlet of the air conditioning heat exchanger (516), and a secondary circuit (52) in which a heat transfer fluid circulates and comprising, in one direction of heat transfer fluid circulation: a secondary pump (522) controlled by the electronic control unit (53), said secondary pump (522) being configured to circulate the heat transfer fluid in the secondary circuit (52) at a flow rate controlled by the electronic control unit (53), a heat exchanger called "of the electric battery" (526) being configured to carry out heat exchanges between the heat transfer fluid and the electric battery (40), a temperature sensor (525) positioned at the inlet of the heat exchanger of the electric battery (526), a three-way valve (521) of which one inlet (521-A) is connected to the primary circuit (51) between the heat exchanger of the electric machine (514) and the air conditioning heat exchanger (516), another inlet (521-B) is connected to the outlet of the heat exchanger of the electric battery (526) in the direction of circulation of the heat transfer fluid and the outlet (521-C) of the three-way valve (521) is connected to the inlet of the secondary pump (522), said electronic control unit (53) being configured to control the performance of the electrical machine (30) and the opening of the three-way valve (521) as well as to receive measurements from the temperature sensors (515, 517, 525), said method comprising the steps of: calculation (E1), by the electronic control unit (53), of the heat exchanges necessary to heat the air circulating in said air conditioning system (20) and to heat the electric battery (40) to target temperatures, calculation (E2), by the electronic control unit (53), of the maximum power that the electrical machine (30) can provide through thermal dissipation to reach the target temperatures, sending (E3), by the electronic control unit (53), a command to the electrical machine (30) to degrade its performance in order to generate a power equal to the calculated power, calculation (E4), by the electronic control unit (53), of the volumetric flow rate (Qm,1) of the heat transfer fluid in the primary circuit (51) necessary to carry out the heat exchanges for the air circulating in the air conditioning system (20), adjustment (E5), of the flow rate of the main pump (512) to ensure in the primary circuit (51) the calculated volumetric flow rate (Qm,1), determination (E6), by the electronic control unit (53), of the thermal power available to heat the electric battery (40), calculation (E7), by the electronic control unit (53), of the volumetric flow rate (Qm,2) of the heat transfer fluid in the secondary circuit (52) necessary to carry out the heat exchanges with the electric battery (40), adjustment (E8) of the secondary pump flow rate (522) to ensure the calculated volumetric flow rate (Qm,2) in the secondary circuit (52), calculation (E9), by the electronic control unit (53), of the position of the three-way valve (521), setting (E10) of the three-way valve (521) to the calculated position.

2. A heating method according to the preceding claim, wherein the electronic control unit (53) can receive a prior heating command, referred to as air conditioning, and wherein the calculation step (E1) of the necessary heat exchanges takes into account the heat exchanges in the air conditioning exchanger (516) only if the air conditioning heating command is received.

3. A heating method according to any one of the preceding claims, wherein the flow rate adjustment of the main pump (512) and / or the secondary pump (522) is carried out by a pre-recorded lookup table between the expected volumetric flow rate in the primary circuit (51) and / or the secondary circuit (52) and the operating speed of the main pump (512) and / or the secondary pump (522).

4. A heating method according to any one of the preceding claims, wherein the calculation step (E9) of the position of the three-way valve (521) is carried out by a pre-recorded lookup table between the incoming volumetric flow rate of the primary circuit (51) and the volumetric flow rate (Qm,2) in the secondary circuit (52).

5. A method according to the preceding claim, wherein the step of determining and adjusting the position of the three-way valve (521) includes a substep of iteratively determining the position of the three-way valve (521) from the measurement of the volumetric flow rate in the primary circuit (51) and the volumetric flow rate (Qm,2) in the secondary circuit (52).

6. Electronic control unit (53) for a vehicle (1) heating system (50), said vehicle (1) comprising an air conditioning system (20), an electric machine (30) and an electric battery (40) configured to supply electricity to said electric machine (30), said heating system (50) comprising a main pump (512), a secondary pump (522), an air conditioning heat exchanger (516) and an electric battery heat exchanger (526), ​​a three-way valve (521) and a plurality of temperature sensors (515, 517, 525), said electronic control unit (53) being configured to: be connected to said main pump (512) and to said secondary pump (522) and control the volumetric flow rates of the main pump (512) and of the secondary pump (522), be connected to said three-way valve (521) and control the opening configuration of the three-way valve (521), to control the performance of the electrical machine (30), be connected to a plurality of temperature sensors (515, 517, 525) and receive the temperature measurements taken by said temperature sensors (515, 517, calculate the heat exchanges necessary to reach a target temperature in said air conditioning heat exchanger (516) and in said electric battery heat exchanger (526).

7. Electronic control unit (53) according to the preceding claim, wherein, the vehicle comprising an inverter (30-1) connected to the electric machine (30), the electronic control unit (53) is further configured to be connected to said inverter (30-1) to control the performance of the inverter (30-1).

8. Heating system (50) for a motor vehicle (1), in particular for a hybrid or electric vehicle, said vehicle (1) comprising an air conditioning system (20), an electric machine (30) and an electric battery (40) configured to supply electricity to said electric machine (30), said heating system (50) comprising an electronic control unit (53) according to any one of claims 6 or 7, a primary circuit (51) in which a heat transfer fluid circulates and comprising in one direction of circulation of the heat transfer fluid: a main pump (512) controlled by said electronic control unit (53), said main pump (512) being configured to circulate the heat transfer fluid in the primary circuit (51) at a flow rate (Qm,1) controlled by the electronic control unit (53), a heat exchanger called "of the electrical machine" (514) configured to carry out heat exchanges between the heat transfer fluid and the electrical machine (30), an air conditioning heat exchanger (516) configured to perform heat exchanges between the heat transfer fluid and air circulating in the air conditioning system (20), and a secondary circuit (52) in which a heat transfer fluid circulates and comprising, in one direction of heat transfer fluid circulation: a secondary pump (522) controlled by the electronic control unit (53), said secondary pump (522) being configured to circulate the heat transfer fluid in the secondary circuit (52) at a flow rate controlled by the electronic control unit (53), a heat exchanger called "of the electric battery" (526) being configured to carry out heat exchanges between the heat transfer fluid and the electric battery (40), a three-way valve (521) of which one inlet (521-A) is connected to the primary circuit (51) between the heat exchanger of the electric machine (514) and the air conditioning heat exchanger (516), another inlet (521-B) is connected to the outlet of the heat exchanger of the electric battery (526) in the direction of circulation of the heat transfer fluid and the outlet (521-C) of the three-way valve (521) is connected to the inlet of the secondary pump (522).

9. Heating system (50) according to the preceding claim, wherein, the vehicle comprising an inverter (30-1) connected to the electric machine (30), the primary circuit (51) comprises an inverter heat exchanger (513-A) upstream of the electric machine heat exchanger (514), said inverter heat exchanger (513-A) being configured to effect heat exchanges between the heat transfer fluid and the inverter (30-1).

10. Motor vehicle (1), in particular a hybrid or electric vehicle, comprising an air conditioning system (20), an electric machine (30), an electric battery (40) configured to supply electricity to said electric machine (30) and a heating system (50) according to any one of claims 8 or 9.

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