Method for controlling motor vehicle alternator

Abstract

The invention relates to a method for controlling an alternator electrically connected to a battery of a motor vehicle and to a first electrical network of the motor vehicle, comprising: a first step (E1) of operating the alternator according to a first mode in which the alternator is electrically connected to the battery of the motor vehicle and to a second electrical network of the motor vehicle; a first current generated by the alternator powers the first electrical network and powers the battery to charge the battery; a second step (E2) of detecting a driving condition in which the intensity of the current flowing in the rotor of the alternator needs to be limited to a first maximum intensity value; then a third step (E3) of operating the alternator according to a second mode in which a second current generated by the alternator powers only the first electrical network; an intensity of a third current flowing in the rotor of the alternator for generating the second current is lower than the first maximum intensity value.

Description

[0001] This invention relates to a method for controlling an alternator in a motor vehicle. It also relates to a device for controlling an alternator in a motor vehicle. Furthermore, it relates to a motor vehicle equipped with such a control device. Finally, it relates to a computer program for implementing the method. And lastly, it relates to a recording medium on which such a program is recorded.

[0002] Motor vehicles with thermal engines must meet the need to reduce their fuel consumption while powering an increasing number of equipment items, particularly lighting functions, passenger cabin thermal comfort management systems, driver assistance systems, and multimedia systems including connectivity services.

[0003] Therefore, the torque generated by the heat engine must provide the energy needed to move the vehicle, but it must also provide enough energy to the alternator to charge the battery and power the vehicle's equipment. However, it is possible that the torque generated by the heat engine is insufficient to meet all of these requirements simultaneously.

[0004] Solutions exist that can improve power management. However, these solutions also have drawbacks.

[0005] The purpose of this invention is to provide an apparatus and method for controlling an alternator in a motor vehicle, which overcomes the aforementioned disadvantages and improves upon known apparatus and methods for controlling alternators in motor vehicles in the prior art.

[0006] Therefore, the present invention relates to a method for controlling an alternator electrically connected to a battery and a first electrical network of a motor vehicle, comprising:

[0007] - First step: Operate the alternator according to the first mode, in which the first current generated by the alternator supplies power to the first electrical network and to the battery to charge the battery;

[0008] - Step Two: Detect the driving situation where the current flowing through the alternator rotor needs to be limited to the first maximum intensity value; then...

[0009] - Third step: Operate the alternator according to the second mode, in which the second current generated by the alternator supplies power only to the first electrical network.

[0010] Furthermore, the intensity of the third current flowing in the rotor of the alternator to generate the second current is lower than the first maximum intensity value.

[0011] In one embodiment, the first maximum intensity value is determined based on the rotational speed of the thermal engine.

[0012] In one embodiment, the first electrical network is a low-voltage network, particularly one whose voltage varies between 12V and 14V or even between 12V and 15.6V, thereby powering a group of equipment in the motor vehicle, including an anti-lock braking system and / or a passenger compartment seat adjustment system and / or a lighting management system and / or a passenger compartment thermal comfort management system and / or a driver assistance system and / or a multimedia system.

[0013] In one embodiment, the first and third steps establish an adjustment loop between the voltage setpoint transmitted to the alternator and the voltage measured at the terminals of the first electrical network.

[0014] In one embodiment, the first step includes applying a first voltage from an alternator to terminals of a first electrical network, the first voltage being strictly greater than a reference voltage of a battery, the reference voltage of which corresponds to a voltage value that, when applied to the terminals of the battery, neither causes the battery to charge nor discharge.

[0015] In addition, the third step includes applying a second voltage from the alternator to the terminals of the first electrical network, the second voltage being less than or equal to the reference voltage of the battery.

[0016] Furthermore, if the second voltage is strictly less than the battery's reference voltage, the third step includes providing a fourth current from the battery to power the first electrical network.

[0017] In one embodiment, the second step includes checking conditions that impose a limit on the intensity of the current flowing in the rotor of the alternator, including:

[0018] - A sub-step that compares the rotational speed of the thermal engine with a first rotational speed threshold for the thermal engine, and

[0019] - A sub-step that compares the temperature of the thermal engine with a first temperature threshold for the thermal engine, and

[0020] - A sub-step that compares the battery's charge level with a first charge threshold for the battery.

[0021] In one embodiment, the method further includes a fourth step of detecting the end of limiting the intensity of the current generated by the alternator, comprising:

[0022] - A sub-step that compares the current speed of the heat engine with a first speed threshold for the heat engine.

[0023] - A sub-step that compares the temperature of the heat engine with a second temperature threshold for the heat engine.

[0024] - A sub-step that compares the current charge level of the battery with a second charge threshold of the battery, wherein the second temperature threshold of the heat engine is strictly lower than the first temperature threshold of the heat engine, and the second charge threshold of the battery is strictly lower than the first charge threshold of the battery.

[0025] In one embodiment, the second step includes determining a second maximum value of the engine torque necessary to make the intensity of the current flowing in the rotor equal to the first maximum intensity value, and transmitting the second maximum value to the heat engine.

[0026] The present invention also relates to an apparatus for controlling an alternator electrically connected to a battery of a motor vehicle and a first electrical network of the motor vehicle, the apparatus comprising hardware and / or software elements (particularly hardware and / or software elements designed for implementing the method according to the invention) and / or the apparatus comprising means for implementing the steps of the method according to the invention.

[0027] The present invention also relates to a motor vehicle equipped with a control device for an alternator according to the present invention.

[0028] The accompanying drawings illustrate, by way of example, embodiments of the control device according to the invention and execution modes of the control method according to the invention.

[0029] Figure 1 This is a first schematic diagram of a motor vehicle equipped with a control device according to an embodiment of the present invention.

[0030] Figure 2 This is a second schematic diagram of a motor vehicle equipped with a control device according to an embodiment of the present invention.

[0031] Figure 3 This is a third schematic diagram of a motor vehicle equipped with a control device according to an embodiment of the present invention.

[0032] Figure 4 This is a flowchart of the control method according to the present invention.

[0033] Figure 5 It is a diagram used to determine the maximum intensity of the current applied to the rotor of the alternator based on the rotational speed of the engine driving the alternator.

[0034] Figure 6 It is a diagram that shows how the maximum intensity of the current applied to the rotor of the alternator can be determined based on the rotational speed of the engine driving the alternator and the current delivered by the alternator.

[0035] Figure 7It is a diagram showing the start and end points for limiting the maximum intensity of the current applied to the rotor of the alternator based on the temperature of the coolant in the engine driving the alternator.

[0036] Figure 8 It is a diagram used to determine the start and end points for limiting the maximum intensity of the current applied to the rotor of the alternator based on the state of charge of the battery powered by the alternator.

[0037] The following is for reference Figures 1 to 8 An example of a motor vehicle 100 is described, which is equipped with a device 10 for controlling an alternator.

[0038] Motor vehicle 100 can be any type of vehicle, such as a passenger car, multi-purpose vehicle, or public transport vehicle. Motor vehicle 100 is equipped with a thermal engine 1 and an alternator 2, the alternator 2 converting a portion of the engine torque supplied by the thermal engine 1 to generate electricity. In one embodiment, motor vehicle 100 can be a thermal vehicle equipped with a mild hybrid powertrain.

[0039] like Figure 2 As shown, the thermal engine 1 supplies a first engine torque C1 to the drive chain, which includes a clutch 7, a gearbox 8, and drive wheels 9. Furthermore, the engine 1 supplies a second engine torque C2 to the alternator of the device 10.

[0040] The device 10 also includes a battery 3, to which the alternator 2 is electrically connected for charging. In the embodiment described, the battery 3 is a so-called low-voltage battery, specifically a so-called "12-volt battery".

[0041] In addition, both the alternator 2 and the battery 3 are electrically connected to the first network 4 (referred to as electrical network 4 or network 4 in the remainder of this document).

[0042] Electrical network 4 is a network that supplies power to the equipment group of the motor vehicle 100, which includes an anti-lock braking system 41 for the passenger compartment and / or a seat adjustment system 42 and / or a lighting management system 43 and / or a passenger compartment thermal comfort management system 44 and / or a driver assistance system 45 and / or a multimedia system 46.

[0043] In one embodiment of the invention, electrical network 4 supplies power to all electrical and electronic components of motor vehicle 100, except for components used for vehicle traction.

[0044] Network 4 is a so-called low-voltage network (its voltage is regulated to around 13 volts), particularly a network where the voltage varies between 12V and 14V or even between 12V and 15.6V. Advantageously, voltage regulation is achieved by a voltage regulator 21 integrated into the alternator 2.

[0045] Figure 3 An embodiment of the electrical architecture of a device 10 electrically connected to network 4 is illustrated schematically.

[0046] Device 10 includes a control unit 5 capable of controlling the voltage U_C applied to the terminals of network 4 and the maximum intensity I_rotor_max of the current flowing in the rotor 22 of alternator 2. Alternator 2 receives the voltage command U_C and the intensity I_rotor_max, thereby generating a current with an intensity limited to I_limited and a voltage U_A, which advantageously approximates the voltage U_C. Control unit 5 then receives a measured value of the voltage U_A applied to the terminals of network 4 in a feedback loop. Therefore, the feedback loop enables control unit 5 to reduce the observed deviation between the desired voltage at the terminals of network 4 and the voltage applied to the terminals of network 4 by means of the correction command U_C. As a note, by convention, when the rotor current intensity I_rotor_max is zero, it means that the intensity of the rotor current is unlimited, and therefore the intensity of the current generated by alternator 2 is also unlimited.

[0047] In the remainder of this document, the terms “driving condition” or “operating point” are used to refer to the operating conditions of the motor vehicle 100, which can be taken into account by the control equipment 10 of the alternator 2 to limit the intensity of the current generated by the alternator 2.

[0048] The conditions of use of motor vehicle 100 at a given time specifically include:

[0049] - The state of charge of battery 3 at a given moment, and / or

[0050] - The temperature of thermal engine 1 or the temperature of the coolant in thermal engine 1 at a given moment, and / or

[0051] - The rotational speed of thermal engine 1 at a given moment, and / or

[0052] - Speed ​​and / or acceleration commands from the driver or automatic speed control system at a given time.

[0053] - Commands for using passenger cabin equipment at a given time (e.g., seat adjustment, air conditioning activation).

[0054] - The external temperature at a given moment,

[0055] - The type or topology of the road on which the vehicle travels at a given time (especially the gradient).

[0056] The control equipment 10 of the alternator advantageously includes a device 6 for determining the operating conditions of the motor vehicle 100, particularly

[0057] -A device for determining the temperature 61 of the coolant in a thermal engine.

[0058] - Device 62 for determining the outside air temperature,

[0059] - A device 63 for determining the type or topology of a road, which may be a geolocation system associated with a map.

[0060] Under certain driving conditions, it is necessary to limit the engine torque demanded by the alternator 2 in order to prioritize the engine torque allocated to the drive chain of the motor vehicle 100. However, the vehicle is designed such that limiting the engine torque demanded by the alternator 2 does not affect the functionality of the equipment powered by the network 4. In other words, the power of the thermal engine 1 is calibrated so that limiting the engine torque demanded by the alternator 2 does not reduce the current supply to the network 4, but only affects the charging of the battery 3.

[0061] In the embodiment, the control device 10 includes an engine control module 101.

[0062] The engine control module 101 can determine whether it is necessary to limit the engine torque C2 allocated to the alternator 2. In response, the control device 10 informs the engine control module 101 of the actual limit of the engine torque C2 by communicating to the engine control module 101 the maximum engine torque that the alternator will request and will never exceed.

[0063] The control device 10 may also include a module 102 for controlling the devices of network 4. The module 102 may specifically determine the power consumption required by the devices of network 4.

[0064] The control device 10 includes means for implementing the control method according to the invention, particularly a processing unit 5, which includes a microprocessor 51, a memory 52, and a communication interface 53. The microprocessor 51 mainly includes the following cooperating modules:

[0065] - Module 511 for operating alternator 2 according to first mode M1, which is capable of cooperating with engine 1.

[0066] - Module 512 is used to detect driving conditions where the intensity of the current generated by the alternator needs to be limited. This module can cooperate with engine control module 101, equipment control module 102, and determining device 6.

[0067] - Module 513 for operating alternator 2 according to second mode M2, which is capable of cooperating with engine 1.

[0068] - A module 514 for detecting and limiting the intensity of the current generated by the alternator 2, which can be used in conjunction with the engine 1.

[0069] The motor vehicle 100 (particularly the control device 10) preferably includes all hardware and / or software elements configured to achieve the methods defined in the present invention or the methods described below.

[0070] The following is for reference Figure 4 A first execution mode of the control method is described. The method according to the invention includes steps E1 to E4, which are executed sequentially.

[0071] In the first step E1, the alternator 2 operates according to the first mode M1, in which the current generated by the alternator supplies power to the first electrical network 4 and to the battery 3 to charge it.

[0072] The first step E1 includes applying a first voltage U1 to the terminals of the first network 4. The first voltage U1 is strictly greater than the reference voltage U_ref of the battery 3. The reference voltage U_ref of the battery corresponds to a voltage value that, when applied to the terminals of the battery 3, neither causes the battery to charge nor discharge.

[0073] Therefore, in the first step E1, the control unit 5 transmits a voltage command U_C_1 for the network terminals to the alternator 2.

[0074] The voltage command U_C_1 is specified such that the voltage U_1 of the current generated by the alternator 2 will be strictly greater than the battery reference voltage U_ref.

[0075] Since the voltage U1 of the current supplied by the alternator 2 is greater than the reference voltage U_ref of the battery, the current from the alternator 2 is used not only to power the electrical network 4, but also to power the battery 3 to charge it.

[0076] Advantageously, the first step E1 includes establishing an adjustment loop between the voltage setpoint U_C_1 transmitted from the control unit to the alternator 2 and the voltage U_1 measured at the terminal of the battery 3.

[0077] When the alternator 2 operates according to the first mode M1, the intensity of the third current flowing in the rotor 22 of the alternator 2 is unrestricted. This third current is referred to as the "rotor current" for the remainder of this document. The rotor current is generated by the alternator's regulator 21 based on a setpoint U_C_1.

[0078] Under certain driving conditions, as described in the following steps of this method, it is necessary to limit the torque C2, which means limiting the rotor current. We proceed to step E2: detect driving conditions where the intensity of the current flowing through the rotor 22 of the alternator 2 needs to be limited to a first maximum intensity value I_rotor_max.

[0079] In other words, in the second step E2, the control unit 5 assesses the need and feasibility of limiting the engine torque demanded by the alternator 2 in order to generate the power consumed by the network 4 and optionally power the battery 3.

[0080] In this embodiment, the engine control module 101 detects the need to limit the engine torque demanded by the alternator 2. Then, the control module 101 sends a request to the control unit 5 to limit the engine torque demanded by the alternator.

[0081] Upon receiving this request, we continued to assess the feasibility of limiting the engine torque requested by alternator 2.

[0082] Module 102, used to control the device, can verify whether the electrical energy consumed by network 4 is less than the maximum output of alternator 2.

[0083] In addition, in step E2, it is verified that battery 3 has sufficient charge to withstand not being immediately charged by the alternator.

[0084] These checks can determine, on the one hand, whether limiting the alternator's output is possible, and on the other hand, postpone battery charging. Advantageously, battery 3 can contain energy reserves, which will be able to mitigate the effects of the limitation.

[0085] In one embodiment, the second step E2 includes checking the conditions under which a limit is imposed on the intensity of the current generated by the alternator 2, including:

[0086] - Sub-step E21: Compare the current rotational speed of the heat engine 1 with the first rotational speed threshold S11 of the heat engine 1, and

[0087] - Sub-step E22: Compare the temperature of the heat engine 1 with the first temperature threshold S21 of the heat engine 1, and

[0088] - Sub-step E23: Compare the current charge level of battery 3 with the battery's first charge threshold S31.

[0089] Figure 5 Graph G1 illustrates an embodiment of substep E21. Graph G1 determines the maximum intensity of the rotor current I_rotor_max (in amperes on the y1 axis) based on the current rotational speed of the thermal engine 1 (expressed in revolutions per minute on shaft x1).

[0090] Graph G1 represents a piecewise linear function comprising five segments G11, G12, G13, G14, and G15. The numerical values ​​represented in Graph G1 are given as examples and may vary according to embodiments of the invention.

[0091] The first segment G11 defines a first range P11 for the rotational speed of the heat engine 1, within which the maximum intensity I_rotor_max is substantially constant and equal to 0.1 amperes for the rotational speed of the heat engine 1 between 0 and 700 revolutions per minute.

[0092] The second segment G12 defines a second range P12 for the rotational speed of the thermal engine 1, within which the maximum intensity I_rotor_max increases very rapidly to 3.4 amperes for engine speeds between 700 and 750 revolutions per minute.

[0093] The third segment G13 represents the stable period of the third range P13 of the rotational speed of the thermal engine 1. Within this third range P13, when the engine speed is between 750 and 1000 revolutions per minute, the maximum intensity I_rotor_max is constant and equal to 3.4 amperes.

[0094] The fourth segment G14 defines a fourth range P14 for the rotational speed of the thermal engine 1, within which the maximum intensity I_rotor_max increases slightly to 4 amps when the engine speed varies between 1000 rpm and 1450 rpm.

[0095] The fifth segment G15 defines a fifth range P15 for the rotational speed of the heat engine 1. Within this fifth range P15, when the engine speed exceeds 1455 revolutions per minute, the maximum intensity I_rotor_max is zero. In other words, when the rotational speed of the heat engine 1 exceeds the first threshold S11 (i.e., exceeds 1455 revolutions per minute), limiting the intensity of the current generated by the alternator is not applicable.

[0096] Figure 6 This is a graph that shows how the maximum intensity of the rotor current (in amperes) can be correlated with the rotational speed of the alternator rotor (in revolutions per minute) and the intensity of the current delivered by the alternator (in amperes). Figure 6 The chart shown in the example applies to a so-called "120-amp" alternator operating at 20 degrees Celsius (i.e., guaranteed to deliver at least 120 amps). Furthermore, line L0 of the table provides the correspondence between the rotational speed (revolutions per minute) of rotor 22 and the rotational speed (revolutions per minute) of the thermal engine 1. Figure 6 China also expressed Figure 5The range of rotor speed values ​​defined in the text is P11, P13, P14, and P15.

[0097] It is worth noting that the chart indicates:

[0098] - The rotational speed of thermal engine 1 is within the range P13. Within this range P13, when the engine speed is between 750 and 1000 revolutions per minute, the maximum intensity I_rotor_max is constant and equal to 3.4 amperes.

[0099] - The range of rotational speed values ​​of the thermal engine 1 is P14. Within this range, when the engine speed varies between 1000 rpm and 1666 rpm, the maximum intensity I_rotor_max increases slightly to 4 amps.

[0100] Therefore, graph G1 can determine whether the thermal engine 1 is operating at an engine speed within the range where the rotor current needs to be limited, i.e., whether the engine speed is within the range P11 to P14. Furthermore, Figure 6 The graph shown correlates the maximum intensity of the rotor current with the current speed of the thermal engine 1.

[0101] Advantageously, in sub-step E21, a second maximum value max_C2 of the engine torque is determined, which is necessary for the intensity of the current flowing in the rotor 22 to be equal to the first maximum intensity value I_rotor_max, and the second maximum value max_C2 is transmitted to the thermal engine 1.

[0102] The embodiment of sub-step E22 is as follows: Figure 7 The graph G2 shown in the figure represents the coolant temperature in degrees Celsius. The vertical axis y2 represents the operating mode of the alternator, which can be:

[0103] - According to mode M1, where the rotor current limiting function is deactivated, or

[0104] - According to mode M2, the rotor current limiting function is activated.

[0105] In sub-step E22, the temperature of the heat engine 1 is compared with a first temperature threshold S21 for the heat engine 1. In fact, for the rotor current intensity limiting function to switch from the off state to the on state, the engine temperature must be sufficiently high, specifically higher than the first temperature threshold S21 of the heat engine. In the embodiment shown in Figure G2, the activation criterion for the limiting function is related to the temperature of the heat engine's coolant and is independent of the temperature of the heat engine itself. For example, if the first temperature threshold S21 is set to 62 degrees Celsius, then in order to activate the rotor current intensity limiting function, the temperature of the heat engine's coolant must be higher than or equal to 62 degrees Celsius.

[0106] The embodiment of sub-step E23 is as follows: Figure 8 The graph G3 shown in the figure represents the battery 3's charge status as a percentage. The vertical axis y3 represents the alternator's operating mode, which can be:

[0107] - According to mode M1, where the rotor current limiting function is turned off, or

[0108] - According to mode M2, the rotor current limiting function is enabled.

[0109] In sub-step E23, the charge level of battery 3 is compared with a first charge threshold S31. In other words, for the rotor current intensity limiting function to switch from the off state to the on state, the charge level of battery 3 must be high enough, specifically greater than or equal to the first charge threshold S31. For example, if the first charge threshold S31 is set to 82%, the charge level of battery 3 must be greater than 82% in order to enable the rotor current intensity limiting function.

[0110] The execution mode of step E2 can be described as follows.

[0111] In sub-step E21, verify that the engine torque is within a range compatible with the limiting rotor current:

[0112] - If this is the case, the method proceeds to step E22.

[0113] Otherwise, the rotor current is not limited and the method loops back to step E2.

[0114] In substep E22, verify that the engine temperature is within a range compatible with the rotor current limit:

[0115] - If this is the case, the method proceeds to step E23.

[0116] Otherwise, the rotor current is not limited and the method loops back to step E2.

[0117] In sub-step E23, verify that the battery charge level is within a range compatible with the rotor current limit:

[0118] - If this is the case, the control unit 5 transmits a message to the control module 101 to convey the value of the maximum engine torque that the alternator will demand, and will never exceed. The method then proceeds to step E3 to limit the rotor current to the first maximum intensity value I_rotor_max determined in step E21.

[0119] Otherwise, the rotor current is not limited and the method loops back to step E2.

[0120] In the third step E3, the alternator 2 operates according to the second mode M2, in which the second current generated by the alternator 2 supplies power only to the first electrical network 4, and the intensity I_rotor of the third current flowing in the rotor 22 of the alternator 2 to generate the second current is lower than the first maximum intensity value I_rotor_max.

[0121] In other words, in step E3, the alternator 2 limits the rotor current intensity I_rotor to the maximum value I_rotor_max determined in step E21.

[0122] Furthermore, the third step E3 includes applying a second voltage U2 from the alternator 2 to the terminals of the first network 4, the second voltage being less than or equal to the reference voltage U_ref of the battery, and if the second voltage U2 is strictly lower than the reference voltage U_ref of the battery 3, the third step includes providing a fourth current from the battery 3 to supply power to the first electrical network 4.

[0123] Therefore, in the third step E3, the control unit 5 transmits a voltage command U_C_2 to the alternator 2 for the network terminals.

[0124] The voltage command U_C_2 is specified such that the voltage U_2 of the current generated by alternator 2 is less than or equal to the battery's reference voltage U_ref. Since the voltage U_2 of the current supplied by alternator 2 is less than or equal to the battery's reference voltage U_ref, the current generated by alternator 2 is used only to power network 4. Therefore, battery 3 is not charged using the current generated by alternator 2.

[0125] Furthermore, when voltage U2 is significantly lower than voltage U_ref, battery 3 discharges to supply power to network 4 in addition to the current supplied by alternator 2.

[0126] Advantageously, the third step E3 includes implementing a regulating loop between the voltage setpoint U_C_2 transmitted from the control unit 5 to the alternator 2 and the voltage U2 measured at the terminal of the network 4.

[0127] Following step E3, the method then proceeds to a fourth step E4, which concludes by detecting and limiting the intensity of the current generated by the alternator 2, including:

[0128] - Sub-step E41: Compare the current speed of the heat engine with the first speed threshold S11 of the heat engine 1.

[0129] - Sub-step E42: Compare the temperature of the heat engine 1 with the second temperature threshold S22 of the heat engine 1.

[0130] - Sub-step E43: Compare the current charge level of battery 3 with the second charge threshold S32 of battery 3.

[0131] - and wherein the second temperature threshold S22 of the heat engine 1 is strictly lower than the first temperature threshold S21 of the heat engine 1, and wherein the second charge threshold S32 of the battery is strictly lower than the first charge threshold S31 of the battery.

[0132] In sub-step E41, in order to switch the rotor current intensity limiting function from the on state to the off state, it is sufficient to increase the engine speed to be greater than the first speed threshold S11 of the thermal engine 1.

[0133] The embodiment of sub-step E42 is as follows: Figure 7 The graphic G2 shown in the figure is illustrated.

[0134] In sub-step E42, the temperature of the heat engine 1 is compared with a second temperature threshold S22 for the heat engine 1. In fact, for the rotor current intensity limiting function to switch from the on state to the off state, it is sufficient for the engine temperature to drop below the second temperature threshold S22 of the heat engine. In the embodiment shown in Figure G2, the criterion for turning off the limiting function is related to the temperature of the heat engine's coolant and is independent of the temperature of the heat engine itself. For example, if the second temperature threshold S22 is set to 60 degrees Celsius, the rotor current intensity limiting function may be turned off because the temperature of the heat engine's coolant has already dropped below 60 degrees Celsius.

[0135] The embodiment of sub-step E43 is as follows: Figure 8 The graphic G3 is shown in the figure.

[0136] In sub-step E43, the charge level of battery 3 is compared with a second charge threshold S32. In other words, for the rotor current intensity limiting function to switch from the on state to the off state, it is sufficient for the charge level of battery 3 to drop below the second charge threshold S32. For example, if the second charge threshold S32 is set to 80%, the rotor current intensity limiting function may be turned off because the charge level of battery 3 has become below 80%.

[0137] Therefore, due to the present invention, the alternator is controlled to prevent it from generating more electricity than the vehicle consumes at the vehicle's current operating point. For example, if the vehicle is idling (in traffic jams, in summer, and at high altitudes), engine performance will decrease, and it is best to limit the amount of current generated by the alternator to only meet the vehicle's needs (i.e., engine cooling and the thermal comfort of the vehicle's passengers). Due to the control method according to the present invention, the remaining available engine torque can then be allocated to meet the vehicle's traction needs or the needs of the vehicle's air conditioning compressor.

[0138] In this invention, limiting the engine torque drawn by the alternator is controlled by limiting the intensity of the current flowing through the rotor, which is a parameter easier to control than the engine torque drawn by the alternator. Furthermore, the solution implemented in this invention includes voltage regulation at the network terminals, which avoids voltage fluctuations in powering vehicle equipment.

[0139] The implementation of limiting the engine torque demanded by the alternator advantageously takes into account the battery's state of charge, providing greater flexibility in its implementation. For example, if the battery has a good charge or is operating for a limited time, the torque demanded by the alternator can be further limited, allowing the battery to discharge and provide a portion of the current needed to power the network operating the equipment. This flexibility enables engine stall prevention, for example, when the engine speed is far below idle speed, or when all available torque is allocated to vehicle traction under very strong acceleration. In this case, the intensity of the current flowing through the rotor can be limited, generating only half the power consumed by the network, with the remaining power dedicated to supplying the network drawn from the battery.

[0140] This invention can also automatically detect when it is appropriate to end the limitation on the engine torque demanded by the alternator. For example, the end of traffic congestion is a typical condition for detecting the cessation of the limitation function. The engine stops idling and the engine speed increases. The alternator no longer limits power generation, and therefore can generate more electrical energy than the car consumes. If the battery supplied current to the grid during the previous limitation period, or if the battery is not fully charged, the excess electrical energy can charge the battery.

[0141] This power management strategy, achieved by the present invention, increases the calibration possibilities during the development of motor vehicles.

Claims

1. A method for controlling an alternator (2), said alternator (2) being electrically connected to a battery (3) of a motor vehicle (100) and a first electrical network (4) of said motor vehicle (100), characterized in that, The method includes: - First step (E1): The alternator (2) is operated according to the first mode (M1), in which the first current generated by the alternator (2) supplies power to the first electrical network (4) and supplies power to the battery (3) to charge it; - Second step (E2): Detect the driving condition where the intensity of the current flowing through the rotor (22) of the alternator (2) needs to be limited to a first maximum intensity value (I_rotor_max), then - Third step (E3): Operate the alternator (2) according to the second mode (M2); in the second mode (M2), the second current generated by the alternator (2) supplies power only to the first electrical network (4); - And wherein the intensity (I_rotor) of the third current flowing in the rotor (22) of the alternator (2) for generating the second current is lower than the first maximum intensity value (I_rotor_max).

2. The method for control according to the preceding claims, characterized in that, The first maximum strength value (I_rotor_max) is determined based on the rotational speed of the thermal engine (1).

3. The method for control according to any one of the preceding claims, characterized in that, The first electrical network is a low-voltage network, particularly one whose voltage varies between 12V and 14V or even between 12V and 15.6V, thereby powering the equipment group of the motor vehicle, which includes an anti-lock braking system and / or a passenger compartment seat adjustment system and / or a lighting management system and / or a passenger compartment thermal comfort management system and / or a driver assistance system and / or a multimedia system.

4. The method for control according to any one of the preceding claims, characterized in that, The first step (E1) and the third step (E3) establish an adjustment loop between the voltage setpoint (U_C) transmitted to the alternator (2) and the voltage (U_A) measured at the terminal of the first electrical network (4).

5. The method for control according to any one of the preceding claims, characterized in that: - The first step (E1) includes applying a first voltage (U_1) from the alternator (2) to the terminals of the first electrical network (4), the first voltage (U_1) being strictly greater than the reference voltage (U_ref) of the battery (3), the reference voltage (U_ref) of the battery corresponding to a voltage value that, when applied to the terminals of the battery (3), neither causes the battery to charge nor discharge. - The third step (E3) includes applying a second voltage (U_2) from the alternator (2) to the terminals of the first electrical network (4), the second voltage being less than or equal to the reference voltage (U_ref) of the battery, and - If the second voltage (U_2) is strictly less than the reference voltage (U_ref) of the battery (3), then the third step (E3) includes the battery (3) providing a fourth current to power the first electrical network (4).

6. The method for control according to any one of the preceding claims, characterized in that, The second step (E2) includes checking the conditions under which a limit is imposed on the intensity of the current flowing in the rotor of the alternator (2), including: - Sub-step (E21) compares the rotational speed of the heat engine (1) with the first rotational speed threshold (S11) of the heat engine (1), and - Sub-step (E22) compares the temperature of the thermal engine (1) with the first temperature threshold (S21) of the thermal engine (1), and - Sub-step (E23) compares the charge level of the battery (3) with the first charge threshold (S31) of the battery.

7. The method for control according to the preceding claims, characterized in that, The method further includes a fourth step (E4) to detect the end of limiting the intensity of the current generated by the alternator (2), the fourth step (E4) including: - Sub-step (E41) compares the current rotational speed of the heat engine with the first rotational speed threshold (S11) of the heat engine (1). - Sub-step (E42) compares the temperature of the heat engine (1) with the second temperature threshold of the heat engine (1) (S22). - Sub-step (E43) compares the current charge level of the battery (3) with the second charge threshold (S32) of the battery (3), and The second temperature threshold (S22) of the heat engine (1) is significantly lower than the first temperature threshold (S21) of the heat generator (1), and The second charge threshold (S32) of the battery is significantly lower than the first charge threshold (S31) of the battery.

8. The method for control according to any one of the preceding claims, characterized in that, The second step (E2) includes determining a second maximum value of the engine torque necessary to make the intensity of the current flowing in the rotor (22) equal to the first maximum intensity value (I_rotor_max), and transmitting the second maximum value to the thermal engine (1).

9. A device (10) for controlling an alternator (2) electrically connected to a battery (3) of a motor vehicle (100) and a first electrical network (4) of the motor vehicle (100), the device comprising hardware and / or software elements (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 21, 22, 41, 42, 43, 44, 45, 46, 51, 52, 53, 61, 62, 63, 101, 102, 511, 512, 513, 514) for implementing the method according to any one of the preceding claims, particularly hardware and / or software elements (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 21, 22, 41, 42, 43, 44, 45, 46, 51, 52, 53, 61, 62, 63, 101, 102) designed for implementing the method according to any one of the preceding claims.

10. A motor vehicle (100) equipped with a device (10) for controlling an alternator (2) according to the preceding claims.

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