Thermal management process for motor vehicles.

Abstract

Method for thermal management of a motor vehicle. The motor vehicle being equipped with a lubrication circuit for lubricating an electric motor driving the motor vehicle, the electric motor comprising a rotor and a stator, the method comprising: - a first step of determining the need to heat a component of the motor vehicle, in particular a passenger compartment or a traction battery of the motor vehicle, - a second step of determining a flow rate of a lubricating fluid to be delivered by a pump in the lubrication circuit to heat a heat transfer fluid in a thermal management circuit of the motor vehicle and to deliver the thermal energy to the component, - and then a third step of controlling the pump to deliver the flow rate. Figure for the abstract: 2

Description

Title of the invention: Thermal management method for motor vehicles.

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

[0002] Existing thermal systems implement heat transfer between an electric motor lubrication circuit and a thermal management circuit responsible for managing the thermal performance of the passenger compartment or the traction battery. Thus, the recovery of heat from the electric motor by the lubricating fluid optimizes the vehicle's thermal management.

[0003] The object of the invention is to provide a thermal system that improves upon known prior art thermal systems. In particular, the invention makes it possible to implement a thermal system that is reliable and efficient and that makes optimized use of the lubrication circuit.

[0004] To this end, the invention relates to a method for thermal management of a motor vehicle, the motor vehicle being equipped with a lubrication circuit intended for the lubrication of an electric motor for driving the motor vehicle, the electric motor comprising a rotor and a stator, the method comprising: - a first step of determining a need to heat an element of the motor vehicle, in particular a passenger compartment or a traction battery of the motor vehicle, - a second step of determining a flow rate of a lubricating fluid to be implemented by a pump of the lubrication circuit to heat a heat transfer fluid of a thermal management circuit of the motor vehicle and to deliver the thermal energy to the element, - then a third step of controlling the pump to implement the flow rate.

[0005] In one embodiment, the flow rate is a function of one or more of the following parameters: - a stator temperature, and / or - rotor temperature, and / or - the temperature of the lubricating fluid, and / or - the amount of heat produced by the electric traction motor, and / or - the conditions of use of the motor vehicle. Furthermore, the conditions of use of the vehicle are - of a first type when cooling of the electric traction motor is required, - otherwise of a second type when cooling of the electric traction motor is not required.

[0006] In one embodiment, a determination of the conditions of use of the motor vehicle takes into account: - an engine power required by the driver, and / or - a required temperature setpoint in the element, and / or - a temperature of the element, and / or - a temperature of the rotor and / or stator and / or lubricating fluid, and / or - the temperature of the air outside the vehicle.

[0007] In one embodiment, the flow rate is a maximum value taken from among - a first flow rate determined as a function of a stator temperature, and / or - a second flow rate determined as a function of a rotor temperature, and / or - a third flow rate determined as a function of a lubricating fluid temperature, and / or - a fourth flow rate determined according to a quantity of heat produced by the electric traction motor and the conditions of use of the motor vehicle.

[0008] In one embodiment, the amount of heat generated by the electric traction motor is estimated as a function of the electrical power generated by the electric traction motor to provide the motor torque required by a driver of the motor vehicle.

[0009] In one embodiment, the lubrication circuit comprises - a first branch of the circuit conveying the lubricating fluid to the rotor and stator of the electric traction motor, and - a second circuit branch arranged in parallel with the first circuit branch, the second circuit branch including a valve, the first and second branches of the circuit extending between a first and a second point of the lubrication circuit. Furthermore, the third step includes determining the state of the valve as being closed, partially open, or fully open.

[0010] In one embodiment, when the vehicle's operating conditions are of a second type, the valve state is determined to be partially or totally open.

[0011] Advantageously, the thermal management method according to the invention comprises a fourth step of commanding a start of the electric traction motor when the vehicle's operating conditions are of a second type and / or when a lubrication fluid temperature is below a minimum threshold.

[0012] Furthermore, in one embodiment, - The pump and a reservoir of lubricating fluid are arranged in series on a third branch of the lubrication circuit, the third branch connecting the first and second points of the lubrication circuit, - the vehicle includes a thermal circuit in which a heat transfer fluid circulates for the thermal management of the component, and - a heat exchanger is placed between the third branch of the lubrication circuit and a branch of the thermal circuit.

[0013] The invention further relates to a thermal management device for an electric vehicle comprising hardware and / or software elements configured to implement the method according to the invention.

[0014] The invention further relates to a motor vehicle comprising a thermal management device according to the invention.

[0015] The invention also relates to a computer program product comprising program code instructions recorded on a computer-readable medium to implement the steps of the process according to the invention when said program is running on a computer or a computer program product downloadable from a communication network and / or recorded on a computer-readable and / or computer-executable data medium, comprising instructions which, when the program is executed by the computer, cause the computer to implement the steps of the process according to the invention.

[0016] The invention further relates to a computer-readable data recording medium on which is recorded a computer program comprising program code instructions for implementing the process according to the invention or a computer-readable recording medium comprising instructions which, when executed by a computer, lead the computer to implement the steps of the process according to the invention.

[0017] The invention further relates to a signal from a data carrier, carrying the computer program product according to the invention.

[0018] Fig. 1 schematically represents a motor vehicle equipped with a thermal system according to an embodiment of the invention.

[0019] Figure 2 illustrates an embodiment of a thermal system according to the invention.

[0020] Figure 3 is a flowchart of a thermal management process according to the invention.

[0021] Figure 4 illustrates a method for determining a lubrication fluid flow rate setpoint without implementing the invention.

[0022] Figure 5 illustrates a method of determining a lubrication fluid flow setpoint with implementation of the invention.

[0023] Fig. 6 illustrates the effect of the rotational speed of a pump in a lubrication circuit on the temperature of a fluid circulating in the lubrication circuit.

[0024] An embodiment of a motor vehicle 100 according to the invention is described below with reference to Figures 1 to 6. The motor vehicle 100 is a motor vehicle of any type, in particular a passenger vehicle or a utility vehicle.

[0025] In an embodiment more specifically described in this document, the motor vehicle 100 is an electric vehicle comprising in particular: - an element 10, 20, in particular a passenger compartment 10, equipped with a heater and / or a traction battery 20, - and an electric traction motor 30, comprising a rotor 31 and a stator 32.

[0026] In the remainder of this document, the terms "motor 30," "electric motor 30," and "electric traction motor 30" are used interchangeably. These terms refer to the electric motor itself, as well as various components associated with and located near the motor 30, such as current converters. In other words, the term "motor" encompasses a set of components dedicated to the operation of the motor 30, including the electric traction chain comprising one or more electric motors and inverters and / or one or more converters and / or one or more chargers.

[0027] The electric motor 30 described in the invention has different modes of operation.

[0028] The electric motor 30 can operate in a first mode in which it does not generate heat, in particular when the vehicle is parked with the engine off.

[0029] Alternatively, the vehicle may be in a so-called "driving" mode in which various engine components generate heat.

[0030] There are also other operating modes of the vehicle in which certain engine components (stator and / or rotor) generate heat while the vehicle is not in a driving mode. In the remainder of this document, such an operating mode is referred to as the "activation mode." In this operating mode, only one component, either the rotor or the stator, can be powered and produce heat. A physical blockage can be applied to the rotor.

[0031] The motor vehicle 100 is equipped with a thermal system 40 according to the invention more specifically illustrated by [Fig.2].

[0032] The thermal system 40 according to the invention includes a lubrication circuit 41 for the lubrication of the motor, in particular the lubrication of a rotor 31 and a stator 32 of the motor.

[0033] The lubrication circuit 41 includes - a first branch 411 conveying the lubricating fluid into the rotor 31 and the stator 32 of the electric motor 30, and - advantageously, a second branch 412 arranged in parallel with the first branch 411, the second branch 412 comprising a valve 414, the first and second branches 412 extending between a first point A and a second point B of the lubrication circuit 41.

[0034] The valve 414 is advantageously controllable to assume different states, including - a closed state, in which valve 414 prevents the lubricating fluid from passing through the second branch 412, - an open state in which the fluid flows freely in the second branch 412.

[0035] The lubrication circuit 41 further comprises a third branch 413 connecting the first and second points A, B of the lubrication circuit 4L. In addition, a pump 415 of the lubrication circuit 41 and a reservoir (or tank) 416 of lubricating fluid are arranged in series on the third branch 413 of the lubrication circuit 4L.

[0036] In addition, the thermal system 40 advantageously includes a means for controlling the flow rate of the pump 415, as well as a means for controlling the valve 414, to control a partial or total closing or opening of the valve 414.

[0037] In an advantageous embodiment, a partial or total opening of the valve 414 allows for modification of the permeability of the lubrication circuit 4L

[0038] The control means for valve 414 allows different degrees of opening of valve 414 to be controlled in order to more precisely control the flow of a lubricating fluid circulating in the third branch 413.

[0039] In the remainder of the document, the term "flow rate" refers to the flow rate of a lubricating fluid circulating in the third branch 413.

[0040] When the valve 414 is at least partially open, the flow rate of the lubricating fluid controlled by the pump 415 can be significantly higher than when the valve 414 is closed. This is because, as the lubricating fluid flows from the first point A to the second point B, it is distributed between the first and second branches 411, 412 of the lubrication circuit 4L. Furthermore, the second branch 412 offers less resistance to the flow of the lubricating fluid than the first branch 411, which supplies the rotor 31 and the stator 32.

[0041] The conditions of use of the motor vehicle 100 may be - of a first type when cooling of the electric motor 30 is necessary, - otherwise of a second type when cooling of the electric motor 30 is not necessary.

[0042] The primary function of the lubricating fluid is to lubricate elements arranged on the lubrication circuit 41, in order to ensure their proper functioning.

[0043] When the operating conditions of the motor vehicle 100 are of the first type, the lubricating fluid also has the second function of cooling the elements arranged on the lubrication circuit 41, for example the rotor 31 or the stator 32.

[0044] The motor vehicle 100 includes a means for determining a temperature of the stator 32, for example a temperature sensor disposed on the lubrication circuit 41 near the stator 32 or directly on the stator 32.

[0045] Similarly, the motor vehicle 100 includes a means for determining a temperature of the rotor 31, for example a temperature sensor disposed on the lubrication circuit 41 near the rotor 31 or directly on the rotor 31.

[0046] Similarly, the motor vehicle 100 includes a means for determining a current temperature of the lubricating fluid, for example a temperature sensor located on the lubrication circuit 41 upstream of the pump 415, or a temperature sensor located in the lubricating fluid reservoir 416. The temperature information could also be obtained using a model.

[0047] The thermal system 40 further includes a thermal circuit 50, in which a heat transfer fluid circulates for the thermal management of the element, such as the traction battery 20 and / or the passenger compartment 10 of the motor vehicle 100.

[0048] A heat exchanger 60 is disposed between the third branch 413 of the lubrication circuit 41 and a branch of the thermal circuit 50. The heat exchanger 60 allows heat transfer between the lubrication circuit 41 and the thermal circuit 50 without the fluids circulating in each of these circuits mixing.

[0049] The heat exchanger 60 can also be called an oil-water heat exchanger. In this case, - the term "water" refers to a heat transfer fluid circulating in the thermal circuit 50, for example the term "water" may refer to glycol water, and - The term "oil" refers to a lubricating fluid circulating in the 4L lubrication circuit

[0050] In the described embodiment, the thermal circuit 50 can transfer heat to an air of the passenger compartment 10 of the motor vehicle 100 via an air heater 70.

[0051] The vehicle advantageously includes means for determining a need to heat a passenger compartment 10 of the motor vehicle 100. These means may include, for example: - a means by which a user can determine a desired temperature in the passenger compartment 10, for example via a button or a touch screen, - a means of measuring a current temperature of the passenger compartment 10, in particular a temperature sensor disposed in the passenger compartment 10; alternatively a sensor may be disposed on the thermal circuit 50 near the air heater 70.

[0052] The motor vehicle 100 may further include a means for determining the temperature of air outside the vehicle, for example a sensor disposed on an external surface of the vehicle, or a means of communication with a meteorological service.

[0053] The motor vehicle 100 also includes means for determining a need to heat a traction battery 20 of the motor vehicle 100. These means may include a temperature sensor disposed on the thermal circuit 50 near the traction battery 20, in particular downstream of the traction battery 20.

[0054] The motor vehicle 100 may advantageously include a controller 90 which determines common operating conditions of the motor vehicle 100. The controller may be part of a system integrating other subsystems of the motor vehicle 100.

[0055] In one embodiment, the controller 90 can, for example, determine the conditions of use of the motor vehicle 100, according to the following parameters: - an engine power required by the driver, and / or - a temperature setpoint required by element 10 as in passenger compartment 10, and / or - a temperature of element 20 such as the traction battery 20, and / or - a temperature of the rotor 31 and / or the stator 32 and / or the lubricating fluid, and / or - the temperature of the air outside the vehicle.

[0056] The invention further relates to a thermal management device 80 comprising a thermal system 40 according to the invention.

[0057] In an advantageous embodiment, the thermal management device 80 comprises means for implementing a method for managing a thermal system 40 according to the invention. In particular, the thermal management device 80 comprises a processing unit 84 including a microprocessor 81, a memory 82, and communication interfaces 83.

[0058] The thermal management device 80, and particularly the microprocessor 81, mainly comprises the following modules which cooperate with each other: - a module 811 for determining the heating requirement of element 10, 20, such as the passenger compartment 10 and / or the traction battery 20 of the motor vehicle 100, this module being able to cooperate with the means for determining the heating requirement of the passenger compartment 10 and the means for determining the heating requirement of the traction battery 20, - a module 812 for determining a flow rate of lubricating fluid to be implemented by the pump 415 of the lubrication circuit 41 to heat a heat transfer fluid of a thermal management circuit of the motor vehicle 100 and to deliver the thermal energy to element 10, 20, such as the passenger compartment 10 or the traction battery 20 of the motor vehicle 100, this module being able to cooperate with the means of determination of a current temperature of the passenger compartment 10, the means for determining a current temperature of the traction battery 20, and the means for determining a current temperature of the lubricating fluid, - a pump control module 813 for the pump 415 to implement the flow of lubricating fluid, this module being able to cooperate with the pump control means 415 and the valve control means 414 - a control module 814 for starting the electric motor 30, this module being able to cooperate with a control means for the electric motor 30, for its starting.

[0059] The motor vehicle 100, in particular the thermal management device 80, preferably comprises all the hardware and / or software elements configured so as to implement the process defined in the object of the invention or the process described below.

[0060] With reference to [Fig.3], a thermal management process is described comprising four stages E1 to E4 which are carried out successively.

[0061] In the first step El, a need to heat the element 10, 20 is determined, such as a passenger compartment 10 and / or a traction battery 20 of the motor vehicle 100.

[0062] In one embodiment, the determination of a need to heat the passenger compartment 10 is carried out by comparing a desired temperature in the passenger compartment 10 to a measurement by a sensor of a current temperature of an air in the passenger compartment 10. Alternatively, the need to heat the passenger compartment 10 could be determined by applying a model taking into account an outside temperature of the vehicle.

[0063] Similarly, determining the need to heat the traction battery 20 is done by comparing a current temperature of the traction battery 20, which can be measured or calculated by applying a model, to a desired range of values. The desired range of values ​​can be determined based on driving parameters, such as driver-controlled power.

[0064] We then proceed to the second step E2 of determining a flow rate of a lubricating fluid to be implemented by a pump 415 of the lubrication circuit 41 to heat a heat transfer fluid of a thermal management circuit of the motor vehicle 100 and to convey the thermal energy to the element 10, 20 such as the passenger compartment 10 and / or the traction battery 20 of the motor vehicle 100.

[0065] [Fig.4] illustrates a step of determining a flow rate of a lubricating fluid without implementation of the invention, and [Fig.5] illustrates the second step E2 with implementation of the invention.

[0066] Whether or not the invention is implemented, the flow rate of the lubricating fluid is determined by selecting a maximum flow rate value taken from - a first flow rate DI calculated as a function of a stator temperature 32, and / or - a second flow rate D2 calculated as a function of a rotor temperature 31, and / or - a third flow rate D3 calculated as a function of a lubricating fluid temperature, and / or - a fourth flow rate D4 calculated based on a quantity of heat produced by the engine, this quantity of heat also being called "thermal losses".

[0067] In one embodiment, the amount of heat generated by the electric motor 30 is estimated as a function of the electrical power generated by the electric motor 30 to provide the motor torque required by a driver of the motor vehicle 100. In other words, the "thermal losses" of the electric motor 30 are evaluated, that is to say, the amount of electrical energy that is dissipated as thermal energy at the motor.

[0068] In the embodiment without the invention illustrated by [Fig.4], for each parameter a separate mapping is used which makes it possible to associate a flow rate of lubricating fluid with the current value of the parameter.

[0069] Thus, - a first Cl mapping is used to determine a first flow rate value associated with the current value of the stator temperature 32, and / or - a second C2 map is used to determine a second flow rate value associated with the current temperature value of rotor 31, and / or - a third C3 map is used to determine a third flow value associated with the current value of the lubrication fluid temperature, and / or - a fourth C4 map is used to determine a fourth flow value associated with the current value of the amount of heat generated by the engine operation.

[0070] The difference between the embodiment according to the invention represented by [Fig.5] and the embodiment without the invention illustrated by [Fig.4] relates to the consideration of a mode of use of the motor vehicle 100 to calculate the flow rate of the lubricating fluid.

[0071] Indeed, in the process according to the invention illustrated by [Fig. 5], the flow rate of the lubricating fluid is determined as a function of one or more of the following parameters: - a temperature of the stator 32, and / or - a temperature of the rotor 31, and / or - a temperature of the lubricating fluid, and / or - a quantity of heat produced by the engine, and / or - the operating conditions of the motor vehicle 100, the operating conditions of the vehicle being - of a first type when cooling of the electric motor 30 is necessary, - otherwise of a second type when cooling of the electric motor 30 is not required.

[0072] In other words, the difference between the embodiment according to the invention represented by [Fig.5] and the embodiment without the invention illustrated by [Fig.4] relates to the calculation of the fourth flow rate value as a function of the vehicle's thermal losses.

[0073] In the invention, the vehicle's operating conditions are taken into account in calculating the value of the fourth flow rate, by choosing between - a fourth C4 map applicable when the vehicle's usage conditions are of the first type, corresponding to a cooling requirement for the electric motor 30, and - a fifth C5 map applicable when the vehicle usage conditions are of the second type.

[0074] Thus, with implementation of the invention, - the first Cl mapping is used to determine a first DI flow rate value associated with the current value of the stator temperature 32, and / or - the second C2 map is used to determine a second flow rate value D2 associated with the current value of the rotor temperature 31, and / or - The third map, C3, is used to determine a third flow rate value, D3, associated with the current temperature of the lubricating fluid, and / or - a map selected from the fourth or fifth map, C4 or C5, is used to determine a fourth flow rate value, D4, associated with the current value of the amount of heat generated by the motor's operation. Thus, by choosing between the fourth and fifth maps to calculate the fourth flow rate value, two parameters are taken into account: the amount of heat produced by the electric motor 30 and the operating conditions of the motor vehicle 100.

[0075] Advantageously, the fifth map allows C5 to use heat from the engine to heat water circulating in the thermal circuit 50 even when the engine produces little heat, in particular an amount of heat not requiring cooling of the electric motor 30. The use of the fifth map corresponds to a mode of use of the lubrication circuit 41 called "heat recovery mode".

[0076] Next, a setpoint flow rate D is calculated as the maximum flow rate value among the first, second, third and fourth flow rates D1, D2, D3, D4.

[0077] We then proceed to the third step E3 of controlling the pump 415 to implement the set flow rate D in the lubrication circuit 41.

[0078] The third step involves determining the state of valve 414 as closed, partially open, or fully open. As previously described, - a partial or total opening of valve 414 allows modification of the permeability of the lubrication circuit 41, and - the control means of valve 414 allows different degrees of opening of valve 414 to be controlled more precisely the flow of a lubricating fluid circulating in the third branch 413.

[0079] In an embodiment more specifically described in this document, the valve 414 is either closed or open.

[0080] For example, - if the setpoint flow rate D calculated in the second step E2 is less than a flow rate threshold, the valve 414 is closed, and all of the lubricating fluid passes through the first branch 411 of the lubrication circuit 41, the first branch 411 passing through the rotor 31 and the stator 32, - otherwise, valve 414 is open and the fluid is distributed between the first and second branches 411, 412.

[0081] In one embodiment, when the vehicle's operating conditions are of a second type, i.e., when the electric motor 30 does not need to be cooled, the state of the valve 414 is determined to be partially or totally open.

[0082] The cooling circuit pump 415 is controlled according to the permeability of the circuit, to control the flow rate setpoint D. In other words, the pump 415 is controlled so that the lubricating fluid circulates according to the setpoint flow rate D, the term "flow rate" referring to the flow rate of a lubricating fluid circulating in the third branch 413.

[0083] Thanks to the presence of the second branch 412 of the circuit (placed in parallel with the first branch 411 passing through the rotor 31 and the stator 32), when the valve 414 is at least partially open, the rotational speed of the pump 415 located on the third branch 413 can be much higher than if the circuit did not contain such a second branch 412. Thus, the flow rate of the fluid in the third branch 413 can be much higher than if the circuit did not contain such a second branch 412.

[0084] Figure 6 illustrates the effect of the pump speed 415 on the lubricating fluid temperature. Figure 6 comprises four graphs, G1 to G4, showing the time evolution of the lubricating fluid temperature: - A first graph, G1, represents the evolution of the lubricating fluid temperature when the rotational speed of the pump motor 415 is equal to 500 revolutions per minute, - a second graph G2 represents the evolution of the lubricating fluid temperature when the rotational speed of the pump motor 415 is equal to 1000 revolutions per minute, - a third graph G3 represents the evolution of the lubricating fluid temperature when the rotational speed of the pump motor 415 is equal to 2000 revolutions per minute, - a fourth graph G4 represents the evolution of the temperature of the lubricating fluid when the rotation speed of the pump motor 415 is equal to 4000 revolutions per minute.

[0085] When time Tl = 6000 seconds is reached, the measured temperatures begin to stabilize, while continuing to increase slightly. Graphs G1 to G4 are observed to begin to diverge, with the temperatures being ranked in the following order: - The lowest fluid temperature (approximately 13 degrees Celsius) corresponds to the fastest running pump motor 415, i.e., at 4000 revolutions per minute, - the next temperature in ascending order of temperature (approximately 14 degrees Celsius) corresponds to the pump motor 415 rotating at 2000 revolutions per minute, - the next temperature in ascending order of temperature (approximately 15 degrees Celsius) corresponds to the pump motor 415 rotating at 1000 revolutions per minute, - the highest temperature (approximately 16 degrees Celsius) corresponds to the pump motor 415 rotating at 500 revolutions per minute.

[0086] Beyond time T2 = 10500 seconds, the graphs continue to diverge. In the two circuits with the highest fluid flow rates, the fluid temperature decreases, indicating that at these speeds (4000 and 2000 revolutions per minute), the fluid transfers a greater amount of heat to element 10, 20.

[0087] On the other hand, in the two circuits using the lowest fluid flow rates, the fluid temperature increases, which shows that these rotation speeds of the pump motor 415 (1000 and 500 revolutions per minute) do not allow for optimization of heat transfer to the element 10, 20 intended to be heated.

[0088] Thus the presence of the second branch 412 of the circuit, as well as the presence of the valve 414, plays an important role in the efficiency of the heat transfer from the lubrication circuit 41 to the thermal circuit 50.

[0089] Following step E3, we proceed to the fourth step E4 of commanding a start of the electric motor 30.

[0090] In a preferred embodiment, the fourth step is executed only if the conditions of use of the electric motor 30 are of the second type, that is to say if the motor does not need to be cooled.

[0091] Advantageously, the fourth step E4 is executed only when a temperature of the lubricating fluid, measured for example in the tank 416, is below a minimum temperature threshold.

[0092] According to one embodiment, in the fourth step, starting the electric motor 30 corresponds to starting the electric motor 30 in an activation mode that is not intended for driving the vehicle but allows the electric motor 30 to warm up, and thus transfer heat to the lubricating fluid. Step E4 can, for example, be performed when the electric motor 30 is not running, and when the occupants have requested heating for the passenger compartment 10.

[0093] Finally, the method and device according to the invention make it possible to take advantage of the existing lubrication circuit 41 to adapt the thermal management strategy of the vehicle, in particular to the driving conditions of the motor vehicle 100.

[0094] Firstly, the proposed technical solution allows, when necessary, for an increase in the flow rate of the lubricating fluid, thanks to the installation of a circuit branch in parallel with the circuit branch supplying the rotor 31 and the stator 32. The increase in the flow rate of the lubricating fluid allows for an increase in heat transfer from the electric motor 30 to the thermal management circuit of the traction battery 20 and the passenger compartment 10 of the vehicle.

[0095] Secondly, the proposed technical solution includes a control of a flow rate of the pump 415 of the lubrication circuit 41 which is capable of taking into account not only the lubrication or cooling requirements of the engine, but also the requirements for recovering heat from the lubrication circuit 41 for heating the passenger compartment 10 and the traction battery 20.

[0096] The proposed technical solution thus allows thermal optimization of the motor vehicle 100, more specifically advantageous in very low temperature conditions.

[0097] Thanks to the control of the lubrication circuit 41 implemented by the invention, the thermal management device allows the implementation of different operating modes described in Table 1.

[0098] [Tables 1] Operating method of the thermal system according to the invention: Lubrication of the electric motor. Necessary cooling of the electric motor. Heat recovery for the thermal circuit. Mode 1: Lubrication only of the electric motor at cold or ambient temperature. YES NO NO Mode 2: Lubrication and cooling of a hot motor with a minimum flow rate imposed by the lubrication. YES YES NO Mode 3: Pure heat recovery mode. NO NO YES Mode 4: Lubrication only of the electric motor at cold or ambient temperature + "Heat recovery mode" YES NO YES Mode 5: Cooling of the electric motor without a minimum flow rate imposed by the lubrication. NO YES YES Mode 6: Lubrication and cooling of a hot motor with a minimum flow rate imposed by the lubrication + "Heat recovery mode" YES YES YES

[0099] Modes 1 and 2 describe modes in which the heat possibly collected by the lubrication circuit 41 is not used to heat a heat transfer fluid circulating in the device's thermal management circuit. Modes 3 Modes 3 through 5 are modes in which any heat collected by the lubrication circuit 41 is used to heat a heat transfer fluid circulating in the device's thermal management circuit. Modes 3 through 5 are modes implementing heat recovery from the lubrication circuit 41 to the thermal management circuit.

[0100] Mode 1 can be obtained, for example, by applying a very low pump speed 415. A small quantity of fluid circulates in the motor, just enough for its lubrication, so the cooling of the electric motor is not implemented.

[0101] Mode 2 implements a circulation of lubricating fluid allowing both lubrication and cooling of the electric motor.

[0102] Mode 3, or "heat recovery mode," is solely for recovering heat supplied by the lubrication circuit 41 of the electric motor to warm the thermal management circuit. The electric motor itself does not need to be lubricated or cooled; it is stopped. However, heat from the lubrication circuit 41 can be recovered to warm the thermal management circuit. Implementing mode 3 may require performing step E4, which restarts the electric motor, when the lubrication fluid temperature is too low to warm the thermal management circuit.

[0103] Modes 4 to 6 are modes combining the "heat recovery" function with Mode 1 or Mode 2: - when the heat recovery mode is combined with Mode 1, the lubrication fluid is simply heated by the lubrication of the rotor 31 and the stator 32; the heat collected by the fluid is transmitted to the thermal management circuit via the heat exchanger 60. - when the heat recovery mode is combined with Mode 2, the lubrication fluid is heated by the lubrication and cooling of the rotor 31 and stator 32; the heat collected by the fluid is transferred to the thermal management circuit via the heat exchanger 60.

[0104] Thus, in the thermal system according to the invention, a flow of lubricating fluid can be implemented in the lubrication circuit 41 solely for the recovery of heat intended for an element 10, 20 that is not located on the lubrication circuit 41, such as a traction battery 20 or a passenger compartment. In other words, the thermal system according to the invention makes it possible to calibrate, according to the heating requirements of the passenger compartment and / or the traction battery 20, a heat transfer between the lubrication circuit 41 and the thermal circuit 50.

[0105] Preferably, if the energy balance of the motor vehicle is favorable, it may be advantageous: - to operate the electric motor 30 in a mode where its efficiency is degraded in order to use a surplus of thermal energy produced at the electric motor 30 by conveying it to the element 10, 20, - rather than operating the electric motor 30 in a mode where its efficiency is optimal and producing heat by other means at the level of the element 10, 20.

Claims

Demands

1. A method for thermal management of a motor vehicle (100), the motor vehicle (100) being equipped with a lubrication circuit (41) for lubricating an electric motor (30) for driving the motor vehicle, the electric motor (30) comprising a rotor (31) and a stator (32), the method being characterized in that it comprises: - a first step (E1) of determining the need to heat a component (10, 20) of the motor vehicle (100), in particular a passenger compartment (10) or a traction battery (20) of the motor vehicle (100), - a second step (E2) of determining the flow rate of a lubricating fluid to be delivered by a pump (415) of the lubrication circuit (41) to heat a heat transfer fluid of a thermal management circuit of the motor vehicle (100) and to deliver the thermal energy to the component (10, 20), - then a third step (E3) of pump control (415) to implement the flow rate.

2. Thermal management method according to the preceding claim, characterized in that the flow rate is a function of one or more of the following parameters: - a temperature of the stator (32), and / or - a temperature of the rotor (31), and / or - a temperature of the lubricating fluid, and / or - a quantity of heat produced by the electric traction motor (30), and / or - operating conditions of the motor vehicle (100), the operating conditions of the vehicle being - of a first type when cooling of the electric traction motor (30) is necessary, - otherwise of a second type when cooling of the electric traction motor (30) is not necessary.

3. A thermal management method according to the preceding claim, characterized in that a determination of the conditions of use of the motor vehicle (100) takes into account, - an engine power required by the driver, and / or - a required temperature setpoint in the element (10), and / or - a temperature of the element (20), and / or - a temperature of the rotor (31) and / or the stator (32) and / or the lubricating fluid, and / or - a temperature of air outside the vehicle.

4. Thermal management method according to the preceding claim, characterized in that the flow rate is a maximum value taken from - a first flow rate determined as a function of a temperature of the stator (32), and / or - a second flow rate determined as a function of a temperature of the rotor (31), and / or - a third flow rate determined as a function of a temperature of the lubricating fluid, and / or - a fourth flow rate determined as a function of a quantity of heat produced by the electric traction motor (30) and the operating conditions of the motor vehicle (100).

5. Thermal management method according to the preceding claim, characterized in that the amount of heat generated by the electric traction motor (30) is estimated as a function of an electrical power generated by the electric traction motor (30) to provide a motor torque required by a driver of the motor vehicle (100).

6. A thermal management method according to any one of the preceding claims, the lubrication circuit (41) comprising - a first circuit branch (411) conveying the lubricating fluid into the rotor (31) and the stator (32) of the electric traction motor (30), and - a second circuit branch 412 arranged in parallel with the first circuit branch (411), the second circuit branch (412) comprising a valve (414), the first and second circuit branches (411, 412) extending between a first and a second point (A, B) of the lubrication circuit (41), characterized in that the third step includes a determination of a state of the valve (414) as being closed, partially open or fully open.

7. Thermal management method according to the preceding claim, characterized in that, when the vehicle's operating conditions are of a second type, the state of the valve (414) is determined to be partially or totally open.

8. Thermal management method according to any one of claims 6 or 7, characterized in that it comprises a fourth step (E4) of controlling a start of the electric traction motor (30) when the vehicle operating conditions are of a second type and / or when a lubrication fluid temperature is below a minimum threshold.

9. A thermal management method according to any one of claims 2 to 5 and according to any one of claims 6 to 8, characterized in that - the pump (415) and a reservoir (416) of lubricating fluid are arranged in series on a third branch (413) of the circuit of the lubrication circuit (41), the third branch (413) of the circuit connecting the first and second point (A, B) of the lubrication circuit (41), - the vehicle includes a thermal circuit (50) in which a heat transfer fluid circulates for the thermal management of the element (10, 20), and - a heat exchanger (60) is arranged between the third branch (413) of the lubrication circuit (41) and a branch of the thermal circuit (50).

10. Thermal management device for an electric vehicle comprising hardware elements (10, 20, 30, 31, 32, 41, 50, 60, 70, 80, 81, 82, 83, 84, 411, 412, 413, 414, 415, 416) and / or software elements (811, 812, 813, 814) configured to implement the method according to any one of the preceding claims.

11. Motor vehicle (100) comprising a thermal management device according to the preceding claim.

12. A computer program product comprising program code instructions recorded on a computer-readable medium for carrying out the steps of the process according to any 20 of claims 1 to 9 when said program is running on a computer.

13. A computer-readable data recording medium on which is recorded a computer program comprising program code instructions for implementing the method according to any one of claims 1 to 9.

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