CONTROL OF MECHANICAL TORQUE RECOVERED IN ELECTRIC MOTOR BRAKING MODE, IN A VEHICLE

Abstract

A control method is implemented in a vehicle comprising an electric drive unit capable of recovering mechanical torque as a function of a braking torque setpoint, and offering at least two different and usable electric motor braking modes, when selected, when the accelerator pedal is in a predefined state. This method includes a step (10-40) in which, when an electric motor braking mode is selected while the accelerator pedal is in the predefined state, a braking torque setpoint is determined as a function of the vehicle's current speed, and then the use of this determined braking torque setpoint is required. Figure 3

Description

Title of the invention: CONTROL OF THE RECOVERED MECHANICAL TORQUE IN ELECTRIC MOTOR BRAKE MODE, IN A VEHICLE Technical field of the invention

[0001] The invention relates to vehicles comprising at least one electric motor capable of recovering a mechanical torque as a function of a braking torque setpoint, and offering at least two different electric motor braking modes, and more precisely the control in such vehicles of the mechanical torque to be recovered when an electric motor braking mode has been selected. State of the art

[0002] Certain vehicles, possibly land-based (and for example of the automobile type), comprise a powertrain (or GMP) comprising at least one electric motor capable of recovering a mechanical torque as a function of a braking torque setpoint, and offer at least two different electric motor braking modes (generally between two and four). It will be noted that generally the aforementioned electric motor is also capable of providing a motor torque which is a function of a motor torque setpoint, to move its vehicle.

[0003] Each electric motor brake mode can be selected by the driver of the vehicle and can be used to brake the vehicle (via an electric motor brake) when the vehicle's accelerator pedal is in a predefined state. Generally, this predefined state corresponds to a percentage of depression of the accelerator pedal which is zero. But this is not an obligation.

[0004] Currently, each electric motor brake mode is associated with a predefined braking torque setpoint. As an illustrative example, a so-called “normal” electric motor brake mode can be associated with a braking torque setpoint equal to -0.6 m / s2, and an increased electric motor brake mode (or “recharge mode” or “brake mode”) can be associated with a braking torque setpoint equal to -1.2 m / s2.

[0005] In certain life situations, the driver may be required to place the accelerator pedal in the predefined state (for example 0% depression). This may be the case in particular when a first vehicle arrives behind a second vehicle which is moving at a speed significantly lower than its own and its driver is prevented from overtaking this second vehicle. When the accelerator pedal is in the predefined state, an electric motor braking phase begins if an electric motor braking mode had previously been selected by the driver. This phase The electric motor brake causes a decrease in the vehicle's speed, and when the latter is lower than the speed of the second vehicle, the driver is forced to re-accelerate so that the speed of his first vehicle becomes substantially equal to that of the second vehicle. Such a situation can cause a lack of pleasure for the vehicle's passengers, and above all causes an overall loss of electrical energy because the electrical energy recovered during deceleration via the electric motor brake is not sufficient to compensate for the electrical energy consumed during re-acceleration. Typically, there is an average loss of 9.5% on electrical energy efficiency.

[0006] The invention therefore aims in particular to improve the situation. Presentation of the invention

[0007] For this purpose, it proposes in particular a control method intended to be implemented in a vehicle:

[0008] - comprising at least one electric motor capable of recovering torque mechanical function of a braking torque setpoint,

[0009] - and offering at least two different and usable electric motor braking modes, if selected, when an accelerator pedal is in a predefined state.

[0010] This control method is characterized by the fact that it comprises a step in which, in the event of selection of an electric motor brake mode while the accelerator pedal is in the predefined state, a braking torque setpoint is determined as a function of a current speed of the vehicle, then a use of this determined braking torque setpoint is required.

[0011] Thanks to the invention, the probability of having an electric motor braking phase causing a reduction in the speed of the vehicle to a value lower than the speed of another vehicle located in front is significantly reduced, which allows an improvement in driving pleasure for the passengers of the vehicle and an improvement in the consumption of electrical energy by the electric motor.

[0012] The control method according to the invention may include other characteristics which may be taken separately or in combination, and in particular:

[0013] - in its step, the determined braking torque setpoint can have a value which decreases when the current speed increases;

[0014] - in its step, we can determine the braking torque setpoint as a function, in addition, the selected electric motor brake mode;

[0015] - in its step, one can use at least two associated speed intervals res respectively to selected braking torque setpoints, and the braking torque setpoint can be determined as a function of whether the current speed belongs to one of these speed intervals used;

[0016] - in the presence of the last two options, in its step, each interval of speeds used can be associated with different chosen braking torque instructions, the number of which is equal to a number of usable electric motor brake modes;

[0017] - in the presence of the last option, in its step, the engine brake modes usable electrical torques can correspond respectively to intervals of mechanical torque values ​​to be recovered which are different;

[0018] - in its step, one can interrupt the use of the electric motor brake mode selected as soon as the accelerator pedal is no longer in the predefined state.

[0019] The invention also proposes a computer program product comprising a set of instructions which, when executed by processing means, is capable of implementing a control method of the type presented above, in a vehicle comprising at least one electric motor capable of recovering a mechanical torque as a function of a braking torque setpoint, and offering at least two different electric motor brake modes which can be used, in the event of selection, when an accelerator pedal is in a predefined state, to control the mechanical torque to be recovered when an electric motor brake mode has been selected.

[0020] The invention also proposes a control device intended to equip a vehicle:

[0021] - comprising at least one electric motor capable of recovering torque mechanical function of a braking torque setpoint,

[0022] - and offering at least two different and usable electric motor braking modes, if selected, when an accelerator pedal is in a predefined state.

[0023] This control device is characterized by the fact that it comprises at least one processor and at least one memory arranged to carry out the operations consisting, in the event of selection of an electric motor brake mode while the accelerator pedal is in the predefined state, in determining a braking torque setpoint as a function of a current speed of the vehicle, then in requiring use of this determined braking torque setpoint.

[0024] The invention also provides a vehicle, possibly of the automobile type, and:

[0025] - comprising at least one electric motor capable of recovering a torque mechanical function of a braking torque setpoint, and a control device of the type presented above, and

[0026] - providing at least two different and usable electric motor braking modes, in selection case, when an accelerator pedal is in a predefined state. Brief description of the figures

[0027] Other characteristics and advantages of the invention will appear on examining the detailed description below, and the attached drawings, in which:

[0028] [Fig.l] schematically and functionally illustrates an exemplary embodiment of a land vehicle comprising an all-electric GMP, a supervision computer, and a control device according to the invention,

[0029] [Fig.2] schematically and functionally illustrates an exemplary embodiment of a supervision computer comprising an exemplary embodiment of a control device according to the invention, and

[0030] [Fig.3] schematically illustrates an example of an algorithm implementing a control method according to the invention. Detailed description of the invention

[0031] The invention aims in particular to propose a control method, and an associated DC control device, intended to allow control of the mechanical torque to be recovered by at least one electric motor MME of a vehicle V offering at least two different electric motor brake modes mfn.

[0032] In the following, it is considered, by way of non-limiting example, that the vehicle V is land-based and of the automobile type. It is for example a car, as illustrated in [Fig.l]. But the invention is not limited to this type of vehicle. It in fact concerns any type of vehicle (land, sea (or river), or air) comprising a powertrain (or GMP) comprising at least one electric motor capable of recovering mechanical torque and offering at least two different electric motor braking modes.

[0033] Furthermore, it is considered in the following, by way of non-limiting example, that the electric motor MME is supplied with electrical energy by a main (or traction) battery BP, rechargeable during recharging phases. But the (each) electric motor MME could be supplied with electrical energy by a fuel cell.

[0034] [Fig.l] schematically shows a vehicle V comprising a transmission chain with electric GMP (and therefore at least one electric motor MME), an on-board network RB, a service battery BS, a main (or traction) battery BP, a converter CV, a supervision computer CS, and a control device DC according to the invention.

[0035] The CV converter is of the DC / DC type (“Direct Current / Direct Current”). It is therefore responsible for converting a direct current from a first voltage to a second voltage.

[0036] The on-board network RB is an electrical power supply network to which electrical (or electronic) equipment (or components) that consume energy are coupled. electric.

[0037] The service battery BS is responsible for supplying electrical energy to the on-board network RB, in addition, here, to that supplied by the CV converter powered by the main battery BP, and sometimes instead, here, of this CV converter. For example, this service battery BS can be arranged in the form of a very low voltage type battery (typically 12 V, 24 V or 48 V). It is rechargeable at least by the (current) converter CV. It is considered in the following, by way of non-limiting example, that the service battery BS is of the 12 V Lithium-ion type.

[0038] The transmission chain has a GMP which is, here, purely electric and therefore which comprises, in particular, an electric motor MME, a motor shaft, and a transmission shaft AT. Here, the term "electric motor" means an electric machine arranged so as to recover a mechanical torque as a function of a braking torque setpoint, in particular to brake its vehicle in an electric motor braking phase (we then speak of supplying a negative output torque), and to supply a motor torque as a function of a motor torque setpoint to move its vehicle when it is supplied with electrical energy (here) by a main battery (we then speak of supplying a positive output torque).

[0039] The operation of the GMP is supervised by a CS supervision computer.

[0040] The driving machine MME is coupled to the motor shaft AM, to provide it with engine torque by rotational drive or to recover mechanical torque when an electric motor brake mode has been selected by the driver of the vehicle V and the accelerator pedal PA of the vehicle V is in a predefined state. This motor shaft AM is here coupled to a reducer RD which is also coupled to the transmission shaft AT, itself coupled to a train T1 of driving wheels, preferably via a differential DV.

[0041] It will be noted that the train T1 is here located in the front part PVV of the vehicle V. But in a variant this train T1 could be that referenced T2 which is located in the rear part PRV of the vehicle V.

[0042] The CV converter is also responsible, here, during the driving phases of the vehicle V for converting part of the electric current stored in the main battery BP to supply the on-board network RB and the service battery BS (to recharge it) with converted electric current.

[0043] It will be noted, as illustrated non-limitingly in [Fig.l], that the CV converter can be part of a CH charger also comprising a recharge calculator (not illustrated) responsible, at least, for controlling the recharges of the main battery BP.

[0044] The main (or traction) battery BP may, for example, comprise electrical energy storage cells, possibly electrochemical (for example of the lithium-ion (or Li-ion) or Ni-Mh or Ni-Cd type). Also, for example, the battery The main BP can be of low voltage type (typically 450 V for illustration). But it could be of medium voltage or high voltage type.

[0045] It will also be noted that in the example illustrated non-limitingly in [Fig. 1] the vehicle V also comprises a distribution box BD to which the service battery BS, the converter CV and the on-board network RB are coupled. This distribution box BD is responsible for distributing in the on-board network RB the electrical energy stored in the service battery BS or produced by the converter CV, for the supply of the electrical components (or equipment) coupled to the on-board network RB according to power supply requests received (in particular from the supervision computer CS of the GMP).

[0046] It will also be noted that the accelerator pedal PA can be actuated (here) by a foot of the driver of the vehicle V, and has a depression percentage pe from which the engine torque setpoint can be defined, which is then representative of the driver's wishes.

[0047] The vehicle V also offers at least two electric motor brake modes mfn which are different and usable, in case of selection by the driver, when the accelerator pedal PA is in a predefined state. Each electric motor brake mode mfn can be used to brake the vehicle V via an electric motor brake performed by the electric motor MME.

[0048] As an illustrative example, the vehicle V may offer a first electric motor braking mode called normal mfl (n = 1) and a second electric motor braking mode called increased (or recharge mode or brake mode) mf2 (n = 2). It will be noted that to these two electric motor braking modes, it is also possible to add a third electric motor braking mode called reinforced (or “brake+ mode”) mf3 (n = 3) and / or a fourth electric motor braking mode called maximum mf4 (n = 4). It will be noted that this fourth electric motor braking mode mf4 can in particular be used when the accelerator pedal PA has a dual function so as to allow the implementation of a so-called “single pedal” function. This function allows, when it has been selected by the driver of the vehicle V, to use the accelerator pedal PA not only to accelerate the vehicle V, but also to decelerate (or brake) the vehicle V.When this single pedal function has been selected, part of the travel of the accelerator pedal PA is reserved for the acceleration of the vehicle V while the other part of the travel of this accelerator pedal PA is reserved for the deceleration of the vehicle V. The distribution of the two parts of the travel of the accelerator pedal PA is configurable during the tuning of the vehicle V. For example, the first 20 percent of depression (or travel) of the accelerator pedal PA can be used to manage the braking of the vehicle V and the remaining 80 percent of depression (or travel) of the pedal . PA accelerator to manage the acceleration of the vehicle V.

[0049] In the following, it is considered, by way of non-limiting example, that the predefined state corresponds to a percentage of depression pe of the accelerator pedal PA which is zero (situation called “pedal release”). But this is not an obligation. Indeed, the predefined state could correspond to a percentage of depression pe of the accelerator pedal PA less than a chosen threshold (for example equal to 5%).

[0050] This predefined state can be determined during the development phase of a vehicle similar to the vehicle V, then a parameter representing it can be stored, for example, in the control device DC (or in the supervision computer CS).

[0051] For example, and as illustrated non-limitingly in [Fig. 1], each electric motor brake mode mfn can be selected by the driver by means of a dedicated control member OCD. In the example illustrated non-limitingly in [Fig. 1] the dedicated control member OCD is part of the steering wheel VV of the vehicle V. But it could be installed in the dashboard of the vehicle V. In another alternative embodiment, each electric motor brake mode mfn could be selected by the driver in a menu which is accessible on a digital screen of a piece of equipment of the vehicle V (such as for example the central instrument panel installed in the dashboard).

[0052] As mentioned above, the invention proposes in particular a control method intended to allow the control of the mechanical torque to be recovered by the electric motor MME when two conditions are met, namely an electric motor brake mode mfn selected and the accelerator pedal PA in its predefined state (of course if the vehicle V is moving).

[0053] This (control) method can be implemented at least partially by the DC control device (illustrated at least partially in Figures 1 and 2) which comprises for this purpose at least one processor PR1, for example a digital signal processor (or DSP ("Digital Signal Processor")), and at least one memory MD. This DC control device can therefore be produced in the form of a combination of electrical or electronic circuits or components (or "hardware") and software modules (or "software"). For example, it can be a microcontroller.

[0054] The memory MD is RAM in order to store instructions for the implementation by the processor PR1 of at least part of the control method. The processor PR1 may comprise integrated (or printed) circuits, or several integrated (or printed) circuits connected by wired or wireless connections. An integrated (or printed) circuit is understood to mean any type of device capable of carrying out at least one electrical or electronic operation.

[0055] In the example illustrated non-limitingly in Figures 1 and 2, the device of DC control is part of the CS supervision computer. But this is not mandatory. Indeed, the DC control device could include its own dedicated computer, or could be part of another computer on board the vehicle V and performing at least one other function.

[0056] As illustrated non-limitingly in [Fig. 3], the (control) method, according to the invention, comprises a step 10-40 which is implemented each time the two aforementioned conditions are satisfied at a given instant, namely an electric motor brake mode mfn has been previously selected by the driver and the accelerator pedal PA has just been placed in its predefined state by this driver.

[0057] Step 10-40 of the method comprises a sub-step 20 in which, when the two aforementioned conditions are satisfied, one (for example the control device DC) determines a braking torque setpoint ccfmn which is a function of the current speed vc of the vehicle V.

[0058] Then, step 10-40 of the method also comprises a sub-step 30 in which one (for example the DC control device) requests the use of this braking torque setpoint ccfmn which has just been determined.

[0059] By taking into account the current speed vc of the vehicle V in determining the braking torque setpoint ccfmn to be used, the probability of having an electric motor braking phase causing a reduction in the speed vc of the vehicle V to a value lower than the speed of another vehicle located in front, and therefore subsequently requiring re-acceleration, is significantly reduced. This results in an improvement in driving pleasure for the passengers of the vehicle V (and in particular the driver) and an improvement in the consumption of electrical energy by the electric motor MME.

[0060] For example, and as illustrated non-limitingly in [Fig. 3], step 10-40 of the method may also comprise a sub-step 10 in which one (for example the control device DC) is informed of the placement of the accelerator pedal PA in its predefined state after an electric motor brake mode mfn has been selected, and of the current speed vc. It will be understood that this is what triggers the performance of sub-step 20 (and therefore the determination of the braking torque setpoint ccfmn to be used).

[0061] Also for example, in sub-step 20 of step 10-40 the determined braking torque setpoint ccfmn may have a value which decreases when the current speed vc increases. This in fact makes it possible to relatively reduce the intensity of the electric motor brake for high current speeds vc, because the higher these speeds (vc) are, the more the re-acceleration of the vehicle V consumes electrical energy. Conversely, this makes it possible to relatively increase the intensity of the electric motor brake for low current speeds vc, because the lower these (vc) are, the less the re-acceleration of the vehicle V consumes electrical energy.

[0062] Also for example, in sub-step 20 of step 10-40 one (for example the DC control device) can determine the braking torque setpoint ccfmn as a function not only of the current speed vc but also of the selected electric motor brake mode mfn. This also makes it possible to take into account the driver's choice regarding the intensity of the electric motor brake.

[0063] Also for example, in sub-step 20 of step 10-40 one (for example the DC control device) can use at least two speed intervals ivm which are respectively associated with selected braking torque setpoints ccfmn. In this case, one (for example the DC control device) can determine the braking torque setpoint ccfmn as a function of whether the current speed vc belongs to one of these speed intervals ivm used.

[0064] As an illustrative example, when using first ivl (m = 1) and second iv2 (m = 2) speed intervals, the first speed interval ivl may be between a minimum value (possibly negative) and 50 km / h, and the second speed interval iv2 may be between 51 km / h and a maximum value (possibly 160 km / h).

[0065] Also as an illustrative example, when using first ivl (m = 1), second iv2 (m = 2) and third iv3 (m = 3) speed intervals, the first speed interval ivl may be between a minimum value (possibly negative) and 50 km / h, the second speed interval iv2 may be between 51 km / h and 100 km / h, and the third speed interval iv3 may be between 101 km / h and a maximum value (possibly 160 km / h). The kilometer values ​​mentioned above are only illustrative examples, and therefore other kilometer values ​​may be used.

[0066] It should be noted that more than three ivm speed intervals could be used, for example four or five, or even more.

[0067] It will also be noted, when also taking into account the selected electric motor brake mode mfn, that in sub-step 20 of step 10-40 each speed interval ivm used can be associated with different braking torque setpoints ccfmn chosen and the number of which is equal to the number of electric motor brake modes mfn which can be used.

[0068] As an illustrative example, when using first ivl, second iv2 and third iv3 speed intervals and first mfl, second mf2 and third mf3 electric motor brake modes (respectively normal, increased (or brake mode) and reinforced (or brake+ mode)), it is possible to use:

[0069] - for the first speed interval ivl, a braking torque setpoint ccfl 1 equal to -0.6 m / s2 for the first electric motor brake mode (normal) mfl, a braking torque setpoint ccfl2 equal to -1.2 m / s2 for the second electric motor brake mode (increased) mf2, and a braking torque setpoint ccfl 3 equal to -1.8 m / s2 for the third electric motor brake mode (reinforced) mf3,

[0070] - for the second speed interval iv2, a braking torque setpoint ccf21 equal to -0.5 m / s2 for the first electric motor brake mode (normal) mfl, a braking torque setpoint ccf22 equal to -1 m / s2 for the second electric motor brake mode (increased) mf2, and a braking torque setpoint ccf23 equal to -1.4 m / s2 for the third electric motor brake mode (reinforced) mf3, and

[0071] - for the third speed interval iv3, a braking torque setpoint ccf31 equal to -0.4 m / s2 for the first electric motor brake mode (normal) mfl, a braking torque setpoint ccf32 equal to -0.8 m / s2 for the second electric motor brake mode (increased) mf2, and a braking torque setpoint ccf33 equal to -1 m / s2 for the third electric motor brake mode (reinforced) mf3.

[0072] The torque values ​​mentioned above are only illustrative examples, and therefore other torque values ​​may be used.

[0073] It will be noted that in an alternative embodiment, in sub-step 20 of step 10-40 the usable electric motor brake modes mfn may correspond respectively to intervals of mechanical torque values ​​to be recovered which are different. In this case, within a speed interval ivm, the braking torque setpoint ccfmn corresponding to an electric motor brake mode mfn can be determined within the interval of mechanical torque values ​​associated with the latter (mfn) as a function of the current speed vc. To determine the braking torque setpoint ccfmn, it is possible, for example, to use correspondence tables (or maps) associated respectively with the different electric motor brake modes mfn and establishing a correspondence between mechanical torque values ​​and speeds of the speed interval ivm concerned. Alternatively, at least one mathematical formula could be used.

[0074] Also for example, and as illustrated non-limitingly in [Fig. 3], step 10-40 of the method may also comprise a sub-step 40 in which it is possible to interrupt (for example the control device DC may trigger the interruption of) the use of the selected electric motor brake mode mfn as soon as the accelerator pedal PA is no longer in its predefined state (possibly when the percentage of depression pe exceeds a chosen threshold, for example equal to 10%). It will be noted that the use of the selected electric motor brake mode mfn could also be interrupted when the driver presses the brake pedal of the vehicle V.

[0075] It will also be noted, as illustrated non-limitingly in [Fig. 2], that the supervision computer CS (or the computer of the DC control device) can also comprise a mass memory MM1, in particular for storing the selected electric motor brake mode mfn and the current speed vc, as well as any intermediate data involved in all its calculations and processing. Furthermore, this supervision computer CS (or the computer of the DC control device) can also comprise an input interface IE for receiving at least the selected electric motor brake mode mfn and the current speed vc, possibly after having shaped and / or demodulated and / or amplified them, in a manner known per se, by means of a digital signal processor PR2.In addition, this CS supervision calculator (or the DC control device calculator) can also include an IS output interface, in particular to deliver each message requiring the use of a determined braking torque setpoint ccfmn, and each possible message to stop the use of the selected electric motor brake mode mfn.

[0076] It will also be noted that the invention also proposes a computer program product (or computer program) comprising a set of instructions which, when executed by processing means of the electronic circuit (or hardware) type, such as for example the processor PR1, is capable of implementing the control method described above to control the mechanical torque that the electric motor MME must recover when an electric motor brake mode mfn has been selected and the accelerator pedal PA is in its predefined state.

Claims

Claims

1. Control method for a vehicle (V) comprising at least one electric motor (MME) capable of recovering a mechanical torque as a function of a braking torque setpoint, and offering at least two different and usable electric motor brake modes, in the event of selection, when an accelerator pedal (PA) is in a predefined state, characterized in that it comprises a step (10-40) in which, in the event of selection of an electric motor brake mode while said accelerator pedal (PA) is in said predefined state, a braking torque setpoint is determined as a function of a current speed of said vehicle (V), then a use of this determined braking torque setpoint is required.

2. Method according to claim 1, characterized in that in said step (10-40) said determined braking torque setpoint has a value which decreases when said current speed increases.

3. Method according to claim 1 or 2, characterized in that in said step (10-40) said braking torque setpoint is determined as a function, in addition, of said selected electric motor brake mode.

4. Method according to one of claims 1 to 3, characterized in that in said step (10-40) at least two speed intervals are used, each associated with selected braking torque setpoints, and said braking torque setpoint is determined as a function of whether said current speed belongs to one of said speed intervals used.

5. Method according to the combination of claims 3 and 4, characterized in that in said step (10-40) each speed interval used is associated with different chosen braking torque setpoints, the number of which is equal to a number of usable electric motor braking modes.

6. Method according to claim 5, characterized in that in said step (10-40) said usable electric motor brake modes correspond respectively to different intervals of mechanical torque values ​​to be recovered.

7. Method according to one of claims 1 to 6, characterized in that in said step (10-40) the use of said selected electric motor braking mode is interrupted as soon as said accelerator pedal (PA) is no longer in said predefined state.

8. Computer program product comprising a set of instructions which, when executed by processing means, is capable of implementing the control method according to one of claims 1 to 7, in a vehicle (V) comprising at least one electric motor (MME) capable of recovering a mechanical torque as a function of a braking torque setpoint, and offering at least two different electric motor brake modes which can be used, in the event of selection, when an accelerator pedal (PA) is in a predefined state, to control the mechanical torque to be recovered when an electric motor brake mode has been selected.

9. Control device (DC) for a vehicle (V) comprising at least one electric motor (MME) capable of recovering a mechanical torque as a function of a braking torque setpoint, and offering at least two different and usable electric motor brake modes, in the event of selection, when an accelerator pedal (PA) is in a predefined state, characterized in that it comprises at least one processor (PR1) and at least one memory (MD) arranged to carry out the operations consisting, in the event of selection of an electric motor brake mode while said accelerator pedal (PA) is in said predefined state, in determining a braking torque setpoint as a function of a current speed of said vehicle (V), then in requiring use of this determined braking torque setpoint.

10. Vehicle (V) comprising at least one electric motor (MME) capable of recovering a mechanical torque as a function of a braking torque setpoint, and offering at least two different electric motor braking modes which can be used, in the event of selection, when an accelerator pedal (PA) is in a predefined state, characterized in that it further comprises a control device (DC) according to claim 9.

Images