WO2020174131A1

WO2020174131A1 - Control of a motor vehicle drive train during assisted-control deceleration

Info

Publication number: WO2020174131A1
Application number: PCT/FR2019/053250
Authority: WO
Inventors: Valentina CIARLA; Stephane TOUZAIN
Original assignee: Psa Automobiles Sa
Priority date: 2019-02-26
Filing date: 2019-12-20
Publication date: 2020-09-03
Also published as: FR3093053A1; EP3931055A1; CN113518740A; FR3093053B1

Abstract

Disclosed is a method for controlling a motor vehicle drive train (GMP) during an assisted control deceleration, comprising determining (E21) a maximum value (123) of braking torque that can be delivered by the drive train, then, taking account of said maximum value (123), determining (E8) a command (301) to be delivered to the drive train (GMP) and applying said command (301) to the drive train, the braking torque maximum value (123) being determined according to the current value of ramping torque of the drive train (GMP).

Description

DESCRIPTION

TITLE OF THE INVENTION: DRIVING A MOTOR VEHICLE MOTORPROPELLER GROUP DURING A

DECELERATION UNDER ASSISTED CONTROL

The invention relates to the field of the management of the power train of a motor vehicle in situations where a driving assistance function defines commands in addition to the possible action of the driver during a movement at low speed.

The invention aims in particular to adapt the command addressed, for deceleration, to the powertrain by the driving assistance function, to the presence of pre-existing creeping behavior on the vehicle.

It is recalled that creeping is a behavior of the powertrain by which a positive torque is transmitted to a drive wheel set while the vehicle is moving at very low speed, the engine is running at low speed and the driver is not pressing on throttle control.

Thus, on a vehicle equipped with a thermal powertrain with an automatic torque converter gearbox, creeping is a result of the operation of the torque converter which partially transmits the rotation of the engine to the wheels.

On a vehicle equipped with an electric traction motor, which may be a vehicle whose power train does not include a heat engine (battery electric vehicle, or even a fuel cell), or a vehicle with thermal hybrid motorization and electric, automatic control of the electric motor is provided to create the creep, which is then artificial.

In these different cases, ramping allows the driver to maneuver the vehicle, controlling the movement using only the brake pedal. The ramping stabilization speed is between 5 and 12 km / h.

This creeping function has thus existed for many years, and the new driving assistance functions, by which the vehicle determines certain commands for the driver in the form of a driving delegation, have just been implemented in a context where rampage is present on vehicles and appreciated by drivers. The two types of function coexist in particular when moving at low speed. Thus, they coexist in a context of concertina driving in traffic jams, where the automatic cruise control function, operating a first form of assisted control, is activated. They still coexist in a context of maneuvering for the parking lot, of the slot or parallel parking type, where a parking assistance function, operating a second form of assisted control, is again activated.

Currently, in the deceleration phase by braking under assisted control, the driving assistance supervisor preferably exploits the negative torque range that can be achieved by the powertrain, from 0 Nm to an extreme negative value, and when this is necessary, complete its action by an action on the hydraulic brake system.

However, in existing systems, the driving assistance supervisor evaluates the minimum torque value (maximum absolute value of negative torque, corresponding to a maximum braking) that can be provided by the powertrain, taking into account the sum losses of the heat engine if such an engine is present in the traction chain and minimum torques of electrical machines of the power train. These values vary depending on the current state of charge of the batteries, their energy recovery capabilities and the coupling states of the powertrain.

Once this braking torque limit that can be supplied by the powertrain is known, the driving assistance supervisor adapts the instruction he sends to the powertrain supervisor.

It has been observed that the ramping function nevertheless tends to defeat the correct implementation of a braking torque setpoint sent to the powertrain by the driving assistance supervisor, when the latter wants to obtain motor braking for a torque of an absolute value greater than that of the ramping torque. In fact, in this situation, the power train does not take into account the demand for braking torque which is greater, in absolute value, than the absolute value of the ramping torque. This phenomenon is qualified as "saturation", by the creeping function, of the braking torque by the powertrain.

This causes a delay in achieving the braking torque requested from the powertrain by the driving assistance supervisor. And it is then necessary for the driver assistance supervisor to use the hydraulic brake system more intensely, abruptly and late, which is undesirable for the wear and tear of the system and the comfort of the passengers. Document FR3002904 discloses adapting the ramping torque to the presence of an obstacle in front of the car. However, there are no plans to coordinate the creeping function of the power train with the driving assistance functions.

To respond to these difficulties, a method is proposed for controlling a motor vehicle during deceleration under assisted control, comprising determining a maximum braking torque value that can be delivered by the powertrain, then , taking into account said maximum value, a preparation of commands to be delivered to the power train and to the hydraulic brake system for deceleration under assisted control.

Remarkably, said maximum braking torque value is determined, if a power train ramping function is active, as a function of a current torque value of said ramping function.

Thus, the automatic piloting system (or driving assistance system) is informed in real time of the presence or not (activation or not) of a ramping and the value of its torque.

This solution guarantees the driver against emergency braking or simply late braking that could occur due to poor torque achievement at low speed. Indeed, the deceleration is obtained by the two commands: that addressed to the power train and that addressed to the hydraulic brake system.

It is also possible to choose, once this solution is available on the vehicle, between activating or deactivating ramping, since, even activated, ramping no longer interferes with assisted control during deceleration. Thus, it is possible to reconcile precision of torque control by the assistance system and obtaining good low-speed approval for the driver.

In addition, the braking devices can be dimensioned exactly as needed, thanks to innovation.

According to optional and advantageous characteristics,

- Said determination of a maximum braking torque value is made taking into account torque ranges transmissible by different components of the powertrain;

- taking into account said maximum value, a range of braking torque values that can be delivered to the wheels by the power train is determined and then sent to a driving assistance supervisor, who uses it to adapt the instructions of braking that it then addresses to the powertrain supervisor and the hydraulic brake system supervisor;

- taking into account said maximum value, a range of braking torque values that can be delivered to the wheels by the power train is determined and then sent to a driving assistance supervisor, who uses it to adapt a setpoint that it then sends it to the powertrain supervisor who takes it into account for the preparation of said order; Thus, the correction of the extreme value of braking torque is fed back to the driving assistance supervisor, which is an organ often separate from the powertrain supervisor, which can carry out complex calculations with a computing power. important, on specific hardware components;

- the commands are determined taking into account a deceleration setpoint determined by an adaptive cruise control function, or by an assisted parking function;

- the commands are determined taking into account a current distance with another vehicle, an obstacle detection, or a reference speed requested by the driver, taken into account for example by an assistance supervisor the driving ;

- the command to be delivered to the powertrain is modified according to the current wishes expressed by the driver on the acceleration control, or according to a current will expressed by the driver on the brake control;

- the command to be delivered to the powertrain is modified according to an energy recovery instruction by an electrical machine of the powertrain transmitted by a supervisor of the hydraulic brake system of the vehicle, for example to a supervisor of the group motor-propellant.

The invention also consists of a motor vehicle comprising means for determining a maximum value of braking torque that can be delivered by a power train of the vehicle, as well as means for determining, taking into account said maximum value, of commands to be delivered to the powertrain and to a hydraulic brake system of the vehicle for a deceleration under assisted control.

Remarkably, during a deceleration under assisted control, said maximum braking torque value is determined, if a ramping function of the power train is active, as a function of a current torque value of said ramping function. According to advantageous and optional characteristics,

the power train comprises an electric motor / generator (reversible electric machine) coupled to a wheel set of the vehicle, providing said crawling function;

the power train comprises a thermal traction engine and a reversible electric machine, said thermal engine and said electric machine being able to be coupled to one another or decoupled from one another, by controlling the machine, to produce electrical energy or maximize torque transmission to the wheels;

the means for determining a command to be delivered to the power train and for applying said command to said power train comprise a driving assistance supervisor integrated into the supervisor of the hydraulic brake system, or external to that here, said maximum braking torque value that can be delivered by the power train being transmitted to said driving assistance supervisor, who uses it to adapt a setpoint taken into account for the preparation of said command.

The invention will be better understood, and other objects, characteristics, details and advantages thereof will emerge more clearly in the explanatory description which will follow given with reference to the appended drawings given solely by way of example illustrating one embodiment. of the invention and in which:

[Fig. 1] Figure 1 shows the architecture of a motor vehicle in which the invention can be implemented.

[Fig. 2] Figure 2 shows all of the control functions implemented in one embodiment of the invention.

[Fig. 3A] Figure 3A shows some aspects of the functions shown in Figure 2 as implemented in the prior art.

[Fig. 3B] Figure 3B shows these functions as implemented according to one embodiment of the invention.

[Fig. 4A] Figure 4A shows an evolution of a motor vehicle according to Figure 1 according to the prior art, in a certain scenario.

[Fig. 4B] Figure 4B shows the same evolution in the same scenario but with the implementation of the invention.

In Figure 1, there is shown a motor vehicle 1 for implementing the invention. The motor vehicle 1 comprises a power unit GMP as well as a front drive wheel set TRMAY and a rear drive wheel set TRMAR. He understands also a hydraulic brake system F and a driver assistance supervisor 10, a powertrain supervisor 20 and a hydraulic brake system supervisor 30.

The GMP powertrain comprises a thermal engine MTH coupled to the front drive wheels set TRM AV by, successively, a front clutch EMBAV, for example with slip and synchronization, a controlled electric machine before MELAV, a gearbox with discrete ratios BV, for example with torque converter, and a front differential DIF1.

The GMP powertrain also includes a MELAR rear electric machine coupled to the TRMAR rear drive wheels by successively a Red reduction gear, an EMBAR rear clutch which can take the form of a single dog clutch and a DIF2 rear differential.

The GMP powertrain comprises, to supply the MELAV front electric machine and the MELAR driven rear electric machine, a so-called "low voltage" electric network operating in direct current at a voltage of around 200 to 300 volts, for example. The front electric machine and the rear electric machine MELAV and MELAR are alternating current electric machines and they receive an alternating current thanks to the presence of inverters OND1 and OND2 which convert the direct current of the "low voltage" network into alternating current. Inverters, in particular, can allow the control of the associated electrical machine.

A very low voltage electrical network, around 12 volts and operating with direct current, is also present in the vehicle.

The battery of the so-called "low voltage" network is called the LV traction battery, while the battery of the very low voltage electrical network is noted BTBT.

The two power grids are interconnected using a CCC direct current to direct current converter.

The on-board network RdB to which various consumers of the motor vehicle 1 are connected is supplied by the very low voltage network.

The powertrain also includes an AD alternator-starter controlled and supplied by the very low voltage electrical network and coupled to the MTH heat engine by a CAD alternator-starter belt on the accessory panel of the MTH heat engine , so that the energy supplied by the MTH heat engine can be used to supply the very low voltage electrical network and recharge the very low voltage battery BTBT, or that, conversely, the energy from this network can be used to set in motion or brake (take torque from) the thermal engine MTH via the alternator-starter AD.

The architecture shown above is just one example. The invention applies in particular to architectures allowing an electric crawling function, which is the case of the motor vehicle of FIG. 1.

Thus this architecture has the MELAV front electric machine which, coupled to the front drive wheel set TRMAV by a gear ratio of the BV gearbox and coupled or decoupled from the thermal engine MTH by opening the front clutch EMBAV, allows to produce the ramping function in a controlled manner.

But if the electric machine before MELAV was not present, this architecture has the AD alternator starter which, coupled to the front drive wheel set TRMAV by a gear ratio of the BV gearbox and the thermal engine MTH, makes it possible to produce the ramping function, in a controlled manner.

The ramping torque is qualified as artificial and can be controlled by external control functions and it can be activated or deactivated depending on the life case.

The driving assistance supervisor 10 responds to a desire of the driver expressed by means of man-machine interfaces. The driver thus sets the adaptive adaptive cruise control to a target speed value, or requests that the car park in parallel or in a row.

We are interested in very low speed operating points, such as docking until the vehicle comes to a stop, takeoff or an automatic parking maneuver in progress. In Figure 2, the relationships between the driving assistance supervisor 10, the powertrain supervisor 20, and the hydraulic brake system supervisor 30 have been shown.

The GMP powertrain is also shown in the figure.

Among other functions, the power train supervisor 20 forms means for determining a maximum value of braking torque that can be delivered by the power train GMP. As will be mentioned later in the text, it takes into account the torque ranges transmissible by various MTH, BV, EMB, MEL components (MTH heat engine, BV gearboxes, EMB clutches and MEL electric machines). of the GMP powertrain. And in general, the driving assistance supervisor 10 and the powertrain supervisor 20 form means for determining a command 301 to be delivered to the GMP powertrain and applying said command 301 to said command. GMP powertrain.

The driving assistance supervisor 10 implements a step E1 of calculating the dynamics of the vehicle as a function of environmental constraints, such as the distance from surrounding vehicles or the presence of obstacles. It takes into account the driver's initial instructions defined by the man-machine interface of the adaptive cruise control or the automatic parking function, in particular a reference speed, or target speed.

At the end of this calculation step El, the driving assistance supervisor 10 has a deceleration setpoint 100 which is used during a step E2 for distributing the deceleration setpoint between the motor unit. thruster and hydraulic brake system. To effect this distribution, the driving assistance supervisor 10 has a range of torque values that the GMP powertrain could apply to the drive wheels. The driving assistance supervisor 10 deduces from this what he can ask of the GMP powertrain, the ends of the communicated torque range of which must not be exceeded, the action of which is privileged, and what must be requested from the brake system F.

At the end of the distribution step E2, the driving assistance supervisor 10 has a deceleration instruction 101 to be sent to the supervisor of the powertrain 20 and a deceleration instruction 102 to be sent to the supervisor of the hydraulic brake system. Obtaining these instructions constitutes the preparation of orders 301 and 302 which will be sent to the GMP powertrain and the hydraulic brake system F.

Thus, taking into account a maximum torque value that the powertrain can provide for braking, which is a limit of a range of braking torque values that can be delivered to the wheels by the GMP powertrain transmitted to the driving assistance supervisor 10, the latter uses it to adapt, during state E2, braking instructions 102 and 103 which it then sends to the powertrain supervisor 20 and to the system supervisor hydraulic brake 30.

The deceleration instruction sent to the power train 101 is, before being sent to the supervisor of the power train 20, the subject of a transformation into torque setpoint during a step E3 for calculating a torque setpoint for the powertrain, also implemented by the driving assistance supervisor 10. At the end of this calculation step E3, a torque instruction sent by the driving assistance 103 is sent from the driving assistance supervisor 10 to the powertrain supervisor 20.

The supervisor of the power train 20 takes into account, during a step E4 of taking into account for the torque setpoint of the power train, said torque setpoint emitted by driving assistance 103 and current states of the powertrain.

This taking into account comprises a correction of the torque setpoint 103 received from the driving assistance supervisor 10 according to the information available within the powertrain supervisor 20, in particular the current states of the various components of the GMP powertrain, as well as a transmission, to the driving assistance supervisor 10, of information making it possible to better prepare the torque setpoint emitted by the driving assistance 103.

At the end of this step of taking into account E4, the supervisor of the power train 20 thus has a part of a corrected torque setpoint 105 which is then taken into account for the setpoint. powertrain torque of the driver's will, and on the other hand a range of torque values accessible by the powertrain 104, which is addressed to the driving assistance supervisor 10.

The supervisor of the powertrain 20 for its part performs a step of taking into account E5 of the corrected torque setpoint 105 to adapt the acceleration setpoint transmitted, to the powertrain, by the driver 200.

At the end of this step of taking into account E5, the supervisor of the power train 20 has a coordinated torque setpoint 106. It takes into account both the elements transmitted by the driving assistance functions. , based on algorithms and measurements made by the car's sensors, and the driver's demand expressed on the accelerator pedal.

Furthermore, on the right part of the figure, the driving assistance supervisor 10 transmits, to the hydraulic brake system supervisor 30, the deceleration instruction sent to the hydraulic braking system 102.

During a step E6 of taking into account for the braking instruction of the will of the driver, carried out by the supervisor of the hydraulic brake system 30, the instruction of braking expressed by the driver 201 by pressing the brake pedal is used to modify the deceleration setpoint sent to the hydraulic braking system 102 into a coordinated braking setpoint 107.

The coordinated braking setpoint 107 is then used during a step of distributing the braking setpoint between hydraulic brakes and regenerative braking by the power train, to express on the one hand a hydraulic brake setpoint 302 which is transmitted. the hydraulic brake system F and on the other hand, an energy recovery instruction by the power train 108 which is sent to the power train supervisor 20.

In the lower part of the figure, the powertrain supervisor 20 takes into account the energy recovery instruction 108 during a step E8 of defining the instructions for the components of the power train, based on the instruction coordinate torque 106.

Step E8 of defining the setpoints for the components of the power train is therefore carried out taking into account the coordinated torque setpoint 106 and the setpoint for energy recovery by the power train 108 and results in the expression of a command to the power train 301. This command to the power train 301 is transmitted to the power train GMP, which comprises the thermal engine MTH, the gearboxes BV, the clutches EMB and the electric machines MEL . Torque and gear ratio instructions are sent to them, as well as when the clutch opens or closes.

During step E8 of defining the setpoints for the components of the power train, the maximum energy recovery value achievable per power train 109 is also established, which is sent to the brake system supervisor. hydraulic 30 for determination during step E7 of the distribution of the braking setpoint between hydraulic brake and regenerative braking by the power train. Indeed, during this distribution step E7, the energy recovery setpoint by power train 108 must not exceed the maximum achievable energy recovery value 109 which was obtained by the brake system supervisor. hydraulic 30 from the powertrain supervisor 20.

In FIG. 3A, there is shown in more detail the internal operation of the supervisor of the power train 20 according to the prior art. First of all, it is specified that the coordinated torque setpoint 106 presented in the previous figure is calculated in two stages, with use of a step for introducing the activation of the ramping function E5 'which acts on a Coordinated torque setpoint 106a produced during step E5 of taking into account for the power train torque setpoint of the driver's wishes. Thus, at the end of step E5 ′ of introducing the activation of the ramping function, the supervisor of the power train 20 defines a torque setpoint coordinated with the ramping 106b which is used during the step E8, previously mentioned, of defining the instructions for the components of the power train.

Figure 3 also shows when the powertrain supervisor 20 obtains instantaneous ranges 350 of torque transmissible by the various components of the powertrain. These ranges 350 are obtained from the GMP powertrain. These ranges 350 are used, within the powertrain supervisor 20, during a step E20 of synthesis of the torque production capacities of the powertrain for the purposes of defining a single instantaneous range of torque transmissible by the engine. powertrain 120.

This instantaneous torque range 120 is taken into account during step E4 for taking into account the torque setpoint of the powertrain of the driving assistance setpoint.

According to the invention, an embodiment of which is shown in FIG. 3B, it is no longer an instantaneous torque range 120 which is transmitted for the purposes of performing step E4, but on the one hand, an instantaneous maximum value of torque transmissible by the power train 121 and, on the other hand, a minimum instantaneous value of torque transmissible by the power train 122. The maximum and minimum instantaneous values 121 and 122 constitute the limits of the instantaneous range 120 used previously.

The maximum instantaneous value 121 is directly taken into account during step E4 for taking into account for the torque setpoint of the powertrain of the driving assistance setpoint.

On the other hand, the minimum instantaneous value 122 is modified during a step E21 of taking into account the creeping in order to constitute an instantaneous minimum value of torque transmissible by the power train group corrected to take account of the creeping 123. If the creeping function is not activated, the corrected minimum instantaneous value 123 which results from this step is unchanged from the minimum instantaneous value 122, and if the ramping function is activated, the value is corrected according to the current instantaneous torque value of the ramping function.

It is the corrected instantaneous minimum value 123 which is taken into account for the purposes of step E4 of taking into account for the torque setpoint of the powertrain of the driving assistance setpoint.

The correction is for example the fact of replacing the minimum instantaneous value 122 by the lowest absolute value of said minimum instantaneous value 122 and the instantaneous torque value of the ramping function. The value thus corrected is the corrected minimum value 123.

Thus, if creeping is physically present, the torque value of the creeping function is introduced into the minimum torque value that can be implemented by the powertrain. If the ramping function is not activated, the torque value is left unchanged (the value 123 is equal to the value 122).

The torque range 104 which is transmitted to the driving assistance supervisor is defined by the corrected instantaneous minimum value 123 and the instantaneous maximum value 121.

In Figure 4A, there is shown a speed decrease scenario without the invention, according to the prior art.

Curve C1 represents the speed of the vehicle in km / h. Curve C2 represents the activation (1) or deactivation (0) of the piloting request by the GMP powertrain. Curve C3 indicates the activation (1) or deactivation (0) of the piloting request by the hydraulic brake system, for example by the ESP function (electronic trajectory corrector).

Cut C4 represents torque values in Nm, negative in the range between 0 and -4000 Nm.

These curves are the torque actually achieved at the wheel 40, the torque setpoint transmitted to the power train supervisor 41 (reference 103 in Figures 2, 3A and 3B), the torque of the power train creep function 42 and the minimum torque of the powertrain 43 transmitted by the supervisor of the powertrain 20 to the driving assistance supervisor 10.

At the start of the scenario, the horizontal speed of the vehicle is positive and a torque produced at the negative wheel causes deceleration. The ramping function does not influence the torque at the wheel because the absolute value of the torque produced at the wheel 40 is less than the value of the torque of the ramping function 42. Thus, the torque setpoint transmitted to the supervisor of the powertrain 41 is produced with success and reliability in the form of the torque produced at the wheel 40. It is further noted that these values 40 and 41 are lower in absolute value than the minimum torque 43 (negative value, absolute value maximum) that the powertrain can produce.

Nevertheless, the torque setpoint transmitted to the power train 41 increases in absolute value and crosses the torque value of the ramping function 42 at an instant t1. From this moment, the torque produced at the wheel 40 follows the ramping torque value 42 which exceeds the torque setpoint transmitted to the powertrain 41, which no longer wants to be the subject of faithful realization. We are talking about saturation.

A little later, at an instant t2, the torque setpoint transmitted to the power train 41 reaches the minimum torque value of the power train 43 and is limited by the latter, because the driving assistance supervisor knows this value. However, this has no impact on the torque produced at the wheel 40 because it is always limited by the torque of the ramping function 42, by the phenomenon of saturation. Steering is imperfect, and there is a delay in applying braking.

From an instant t3, the driving assistance supervisor 10 decides to compensate for the insufficient achievement of the torque by means of a deceleration setpoint by the hydraulic brake system F as can be seen on curve C3 . The vehicle is then braked harder and faster. There is no longer any braking control by the GMP powertrain, as can be seen on curve C2. The passengers and the driver have an unsatisfactory experience, and the brakes are applied beyond what would have been desirable.

In Figure 4B, the same scenario is shown but with the implementation of the invention, allowing better coordination of the deceleration setpoint with the torque value of the ramping function.

Curve Cl ’presents the speed, while curves C2’ and C3 ’represent, as before, the activation or deactivation of piloting by the powertrain or piloting by the hydraulic brake system F.

Curve C4 ’represents the torque values in Nm.

Curve 50 represents the torque produced at the wheel, while curve 51 represents the torque setpoint transmitted to the supervisor of the power train 20 and curve 52 represents the torque value of the ramping function. Curve 53 represents quant to it the minimum torque that can be produced by the GMP powertrain, as known to the driving assistance supervisor 10.

In this scenario, with the invention, the torque value of the creep function (curve 52) is coordinated with the minimum torque value that can be provided by the GMP powertrain (curve 53). The result is that ramping does not influence the faithful achievement of the braking torque setpoint, because the torque setpoint transmitted to the GMP power train does not cross the torque value of the ramping function and remains constantly lower. to this in absolute value.

The result is that the torque produced at the wheel (curve 50) faithfully follows the torque setpoint transmitted to the supervisor of the power train 20 (curve 51) and that, when at the instant tl ', the hydraulic brake system F is engaged, the cumulative effect of the torque produced at the wheel has been more pronounced than in the prior art, which implies a better quality of braking smoothly, with a good transition of the regenerative braking by the powertrain towards braking by the hydraulic brake system F.

It has thus been shown how the driving assistance supervisor 10 could ask the powertrain supervisor 20 to achieve a torque setpoint until the saturation of the minimum achievable torque limit, without saturation, so that the setpoint is carried out faithfully, and that the transition to braking by the hydraulic brake circuit, with the ESP function, can be done smoothly and smoothly.

It is specified that the driving assistance supervisor 10 visible in FIGS. 2, 3A and 3B is incorporated in the supervisor of the hydraulic brake system 30 as part of the automatic parking function, without the principles presented being given. in question.

Conversely, in the adaptive regulator function, the driving assistance supervisor 10 is separate from the hydraulic brake system supervisor 30, external to it. It then has specific computer equipment, which can have high computing power.

As mentioned in relation to FIG. 1 and the position of the electric machines, the motor vehicle can be equipped with a hybrid motorization of the full-hybrid type (parallel hybridization with two traction motors, one thermal and the other electric) , or mild-hybrid (light hybrid, with a thermal traction engine assisted by an electric assistance motor / generator, power too modest to allow the vehicle itself to be pulled). The vehicle's power battery (LV “low voltage” battery visible in figure 1) can be rechargeable on an external network using a wired or induction connection, or not be rechargeable other than by the regeneration obtained via the electric motor / generator. The vehicle can also be an electric vehicle with a battery or a fuel cell.

Claims

[Claim 1]. A method of controlling a motor vehicle (1) during deceleration under assisted control, comprising a determination (E20, E21) of a maximum braking torque value (123) that can be delivered by a power train ( GMP) of the vehicle, then, taking into account said maximum value (123), a preparation (E2) of commands to be delivered to the powertrain (GMP) and to the hydraulic brake system (F) for deceleration under assisted control , characterized in that said maximum value (123) is determined (E21), if a creeping function of the power train (GMP) is active, taking into account a current torque value of said creeping function.

[Claim 2]. Driving method according to claim 1, characterized in that, taking into account said maximum value (123), a range of braking torque values (104) which can be delivered to the wheels by the power train (GMP) is transmitted to a driving assistance supervisor (10), who uses it to adapt (E2) braking instructions (102, 103) which he then sends to the powertrain supervisor (20) and to the system supervisor hydraulic brake (30).

[Claim 3]. Piloting method according to claim 1 or claim 2, characterized in that said determination (E20, E21) is made by taking into account (E20) ranges (350) of torques transmissible respectively by different members of the power train (MTH , BV, EMB, MEL).

[Claim 4]. Control method according to one of claims 1 to 3, characterized in that the commands to be delivered to the power train (GMP) and to the hydraulic brake system (F) take account of a determined deceleration setpoint (100) (El) by an adaptive cruise control function, or by an assisted parking function.

[Claim 5]. Control method according to one of claims 1 to 4, characterized in that the commands to be delivered to the power train (GMP) and to the hydraulic brake system (F) for controlled deceleration assisted are determined taking into account (El) a current distance with another vehicle, an obstacle detection, or a reference speed requested by the driver.

[Claim 6]. Piloting method according to one of claims 1 to 5, characterized in that the command to be delivered to the power train (GMP) is modified (E5) according to the current desire expressed by the driver on the acceleration command (200), or modified (E8) according to a current wish expressed by the driver on the brake control (201).

[Claim 7]. Control method according to one of claims 1 to 6, characterized in that the command to be delivered to the power train (GMP) is modified (E8) as a function of an energy recovery setpoint by an electrical machine of the power train (108) transmitted by a supervisor (30) of the hydraulic brake system (30) of the vehicle (1).

[Claim 8]. Motor vehicle (1) comprising means for determining (20) a maximum value of braking torque (123) that can be delivered by a power train (GMP) of the vehicle (1), as well as means for determining ( 10, 20), taking into account said maximum value (123), of commands (301) to be delivered to the powertrain (GMP) and to a hydraulic brake system (F) of the vehicle (1) for a deceleration under assisted control, characterized in that said maximum value (123) is determined, if a creeping function of the power train (GMP) is active, as a function of a current value of torque of said ramping function.

[Claim 9]. Motor vehicle according to Claim 8, characterized in that the means for determining (10, 20) a command (301) to be delivered to the power train (GMP) and for applying said command (301) to said motor unit - thruster (GMP) comprise a driving assistance supervisor (10) integrated into the supervisor of the hydraulic brake system (30), or external to it, said maximum value (123) being able to be delivered by the power unit thruster (GMP) being transmitted to said driving assistance supervisor (10), which uses it to adapt an instruction (103) taken into account for the preparation of said order (301).

[Claim 10]. Motor vehicle according to Claim 8 or Claim 9, characterized in that the power train (GMP) comprises a controlled electric machine (MELAV; AD) coupled to a train of wheels of the vehicle, providing said crawling function.