阅读说明：本技术 在辅助控制下减速期间的机动车辆动力总成操控 (Motor vehicle powertrain handling during deceleration under auxiliary control ) 是由 V·恰拉 S·图赞 于 2019-12-20 设计创作，主要内容包括：本发明公开了一种操控方法,所述操控方法用于在辅助控制下减速期间操控机动车辆的动力总成(GMP),所述操控方法包括：确定(E21)可由所述动力总成传送的最大化制动转矩值(123),然后,通过考虑到所述最大化制动转矩值(123),确定(E8)要传送到所述动力总成(GMP)的命令(301),并且把所述命令(301)应用到所述动力总成,所述最大化制动转矩值(123)根据所述动力总成(GMP)的即时蠕行转矩值进行确定。(The invention discloses a control method for controlling a motor vehicle's drive train (GMP) during deceleration under auxiliary control, comprising: -determining (E21) a maximum braking torque value (123) deliverable by the powertrain, -then-determining (E8) a command (301) to be delivered to the powertrain (GMP) by taking into account the maximum braking torque value (123), the maximum braking torque value (123) being determined from an immediate creep torque value of the powertrain (GMP), and-applying the command (301) to the powertrain.)

1. A steering method for steering a motor vehicle (1) during deceleration under auxiliary control, comprising: -determining (E20, E21) a maximum braking torque value (123) deliverable by a powertrain (GMP) of the motor vehicle, and then-preparing (E2) commands to be delivered to the powertrain (GMP) and to a hydraulic braking system (F) for deceleration under assistance control by taking into account the maximum braking torque value (123), characterized in that, when a creep function of the powertrain (GMP) is activated, the maximum braking torque value (123) is determined (E21) by taking into account an instantaneous torque value of the creep function.

2. Steering method according to claim 1, characterized in that by taking into account said maximum braking torque value (123), a braking torque value range (104) that can be transmitted by the powertrain (GMP) to the wheels is transmitted to a driving assistance monitor (10) which uses it to adapt (E2) the braking setpoint values (102, 103) that are subsequently sent to the powertrain monitor (20) and to the hydraulic braking system monitor (30).

3. The steering method according to claim 1 or 2, characterized in that the determination (E20, E21) is made by taking into account (E20) torque ranges (350) that can be transmitted by different components (MTH, BV, EMB, MEL) of the powertrain, respectively.

4. Steering method according to any of claims 1 to 3, characterized in that the command to be transmitted to the powertrain (GMP) and hydraulic braking system (F) takes into account a deceleration set point (100) determined (E1) by an adaptive speed regulator function or by a parking assist function.

5. Steering method according to any of claims 1 to 4, characterized in that the command for deceleration under assistance control to be transmitted to the powertrain (GMP) and hydraulic braking system (F) is determined by taking into account (E1) the instantaneous distance from another vehicle, the detection of an obstacle or a reference speed requested by the driver.

6. The steering method according to any one of claims 1 to 5, characterized in that the command to be transmitted to the powertrain (GMP) is modified (E5) according to an immediate will expressed by the driver relating to an acceleration controller (200) or (E8) according to an immediate will expressed by the driver relating to a brake controller (201).

7. Steering method according to any one of claims 1 to 6, characterized in that the command to be transmitted to the powertrain (GMP) is modified (E8) as a function of a powertrain motor recuperation energy setpoint (108) transmitted by a hydraulic brake system (30) monitor (30) of the motor vehicle (1).

8. A motor vehicle (1) comprising: -determination means (20) for determining a maximum braking torque value (123) deliverable by a powertrain (GMP) of said motor vehicle (1), and-determination means (10, 20) for determining a command (301) to be delivered to the powertrain (GMP) and to a hydraulic braking system (F) of said motor vehicle (1) for deceleration under auxiliary control by taking into account said maximum braking torque value (123), characterized in that said maximum braking torque value (123) is determined as a function of an instantaneous torque value of a creep function of said powertrain (GMP) when said creep function is activated.

9. A motor vehicle according to claim 8, characterized in that the determining means (10, 20) for determining the command (301) to be transmitted to the powertrain (GMP) and applying said command (301) to the powertrain (GMP) comprise a driving assistance monitor (10) integrated with or external to a hydraulic braking system monitor (30), to which a maximum braking torque value (123) transmittable by the powertrain (GMP) is transmitted, said driving assistance monitor using said maximum braking torque value to adapt the braking setpoint (103) considered for preparing the command (301).

10. A motor vehicle according to claim 8 or 9, characterized in that the powertrain (GMP) comprises a steered electric machine (MELAV; AD) coupled to a wheel axle of the motor vehicle to provide the crawling function.

Technical Field

The present invention relates to the field of managing the powertrain of a motor vehicle in situations in which the driving assistance function defines commands during low-speed movements in addition to optional actions by the driver.

The invention is particularly intended to adapt the command for deceleration sent by the driving assistance function to the powertrain to the presence of creep (rampage) behaviour pre-existing on the vehicle.

Background

It is noted that creep is an action of the powertrain by which a positive torque is transmitted to the powered wheel axle while the vehicle is traveling at a very low speed, the engine is turning at a low speed, and the driver is not pressing on the acceleration control.

Thus, on a vehicle equipped with a thermodynamic assembly having an automatic gearbox with a torque converter, the creep results from the operation of the torque converter (which partially transmits the rotation of the engine towards the wheels).

On vehicles equipped with traction motors, which may be vehicles whose drive train does not comprise an internal combustion engine (battery-operated electric vehicles, even fuel cell electric vehicles), or vehicles with a thermoelectric hybrid drive system, the automatic operation of the electric motor is designed to produce creep, which is thus artificial.

In these different situations, the crawling driver is able to maneuver the vehicle by steering the movement only by means of the brake pedal. The steady speed of the creeping motion is between 5km/h and 12 km/h.

Thus, this creep function has existed for many years, and in the background of creep existing on the vehicle and being appreciated by the driver, a new driving assistance function has recently been installed, by which the vehicle determines some commands in place of the driver in the manner of a driving request.

These two functions coexist, particularly at low forward speeds. In this way, both functions coexist in the context of a stop-and-go (en accord ion) drive in traffic congestion, wherein an automatic speed regulator function in the form of a first auxiliary control is activated. In the context of a maneuver for plug-in parking or for sporadic parking, both functions coexist, with a parking assistance function in the form of a second assistance control being activated there.

At present, in the deceleration phase, in which the deceleration is carried out by braking under assistance control, the driving assistance monitor preferably uses the negative torque range (from 0Nm to extremely negative values) that can be carried out by the powertrain, and supplements its own action, when necessary, by the action of the hydraulic braking system.

However, in existing systems, the driving assistance monitor evaluates the minimum torque value that can be provided by the powertrain (the maximum absolute value of negative torque, corresponding to maximum braking) by taking into account the total losses of the internal combustion engine (when such an engine is present in the traction chain) and the minimum motor torque of the powertrain. These values vary depending on the instant state of charge of the battery, the energy recovery capability of the battery, and the coupling state of the powertrain.

Once this limit of braking torque that can be provided by the powertrain is known, the drive assist monitor adapts the set point that it sends to the powertrain monitor.

It has been observed that when the driving assistance monitor wants to obtain an engine brake for torques in which the absolute value is greater than the absolute value of creep torque, the creep function anyway tends to prevent a good implementation of the braking torque set point sent by the driving assistance monitor to the powertrain. In fact, in this case, the powertrain does not take into account the request for a braking torque that is greater in absolute value than the absolute value of the creep torque. This phenomenon is referred to as "saturation" of the powertrain braking torque due to creep function.

This results in a delay in the implementation of the braking torque requested by the driving assistance monitor to the powertrain. Thus, for the driving assistance monitor, a stronger, more sudden and later use of the hydraulic brake system is required, which is not desirable for wear of the system and comfort of the passengers.

Document FR3002904 discloses adapting creep torque to the presence of obstacles in front of a vehicle. However, it is not designed to coordinate the creep function of the drive-train with the driving assistance function.

Disclosure of Invention

In order to solve these problems, the present invention provides a steering method for steering a motor vehicle during deceleration under assist control, the steering method including: a maximum braking torque value deliverable by the powertrain is determined, and then a command to be delivered to the powertrain and hydraulic braking system for deceleration under assist control is prepared by taking into account the maximum value.

Notably, the maximum braking torque value is determined in accordance with an immediate torque value of the creep function when the creep function of the powertrain is activated.

Thus, the automatic control system (or the driving assistance system) is informed in real time of the presence (activation) of creep and the creep torque value.

This solution makes it possible to ensure that the driver is not faced with emergency braking or simply delayed braking that may occur due to insufficient torque implementation at low speeds. In fact, said deceleration is obtained by the following two commands: a command sent to the powertrain and a command sent to the hydraulic brake system.

Once this solution is available on the vehicle, it is also possible to choose between activating the creep or deactivating it, since even if it is activated, it no longer interferes with the auxiliary control during deceleration. Thereby, the precise handling of the torque by the assistance system and the driver's achievement of good vehicle conditions at low speeds can be coordinated.

Furthermore, due to the innovations, the braking member can be sized as needed.

According to an optional and advantageous feature,

-making a determination of said maximum braking torque value by taking into account the range of torques that can be transmitted by the different members of the powertrain;

-by taking into account said maximized value, a range of braking torque values that can be transmitted by said powertrain to the wheels is determined and then transmitted to a driving assistance monitor, which uses said range of braking torque values to adapt the braking set-point values that are then sent to the powertrain monitor and to the hydraulic braking system monitor;

-by taking into account said maximized value, a range of values of braking torque transmittable by said powertrain to the wheels is determined and then transmitted to a driving assistance monitor, said driving assistance monitor using said range of values of braking torque to adapt a set value subsequently sent to the powertrain monitor, said powertrain monitor taking into account said set value for preparing said command; thus, corrections to brake torque extremes are submitted to the driving assistance monitor, which is a component that is typically separate from the powertrain monitor that can perform complex calculations with greater computational power on specific hardware components;

-said command is determined by taking into account a deceleration set-point determined by an adaptive speed regulator function or by an assisted parking function;

the command is determined by taking into account the instantaneous distance from another vehicle, the detection of an obstacle or a reference speed requested by the driver, for example to be taken into account by a driving assistance monitor;

-the command to be transmitted to the powertrain is modified according to an immediate will expressed by the driver relating to an acceleration control or according to an immediate will expressed by the driver relating to a brake control;

-the command to be transmitted to the powertrain is modified according to a powertrain motor recuperation energy set point transmitted by a hydraulic brake system monitor of the vehicle, for example to a powertrain monitor.

The invention also relates to a motor vehicle comprising: determining means for determining a maximum braking torque value transmittable by a powertrain of said vehicle, and determining means for determining a command for deceleration under assistance control to be transmitted to the powertrain and to the hydraulic braking system of said vehicle by taking into account said maximum value.

Notably, the maximum braking torque value is determined in accordance with an immediate torque value of the creep function when the creep function of the powertrain is activated during deceleration under assist control.

According to an optional and advantageous feature,

-the powertrain comprises a steered engine/generator (reversible electric machine) coupled to a wheel axle of the vehicle to provide the creep function;

-said powertrain comprises a traction internal combustion engine and a reversible electric machine, which can be coupled to each other or uncoupled from each other by means of a manipulation of said machines, in order to generate electric energy or to maximize the torque transmitted to the wheels;

the determination means for determining the command to be transmitted to the powertrain and applying it to the powertrain comprise a driving assistance monitor, integrated with or external to a hydraulic braking system monitor, to which a maximum braking torque value transmittable by the powertrain is transmitted, the driving assistance monitor using the maximum braking torque value to adapt the set value considered for preparing the command.

Drawings

The invention will be better understood and other objects, features, details and advantages thereof will become more apparent from a reading of the following detailed description and the accompanying drawings, given by way of example only, in which:

fig. 1 shows the architecture of a motor vehicle in which the invention can be implemented.

Fig. 2 shows a combination of control functions implemented in an embodiment of the invention.

Figure 3A illustrates some aspects of some of the functions illustrated on figure 2, for example implemented in the prior art.

Fig. 3B shows these functions, for example implemented according to an embodiment of the invention.

Fig. 4A shows a motor vehicle according to fig. 1 in a scenario according to the prior art.

Fig. 4B shows the same evolution in the same scenario but by implementing the invention.

Detailed Description

On fig. 1, a motor vehicle 1 for implementing the invention is shown. Motor vehicle 1 comprises a powertrain GMP and a front powered wheel axle TRMAY and a rear powered wheel axle TRMAR. The motor vehicle further comprises a hydraulic brake system F as well as a driving assistance monitor 10, a powertrain monitor 20 and a hydraulic brake system monitor 30.

The drive train GMP comprises an internal combustion engine MTH coupled in turn to a front powered wheel axle TRMAV via a (e.g. slipping and synchronous) front clutch EMBAV, a steered front electric machine MELAV, a gearbox BV of the discrete transmission type (e.g. with a torque converter) and a front transfer case DIF 1.

The powertrain GMP also comprises a rear motor melt which is coupled, in turn, to the rear powered wheel axle TRMAR via a reducer Red, a rear clutch EMBAR (which may take the form of a single-claw coupling) and a rear transfer case DIF 2.

To supply both front motor MELAV and rear controlled motor MELAR, powertrain GMP includes a so-called "low-voltage" electrical network that operates on direct current at a voltage of, for example, approximately 200 to 300 volts. Front motor MELAV and rear motor MELAR are ac-type motors and receive ac power as a result of inverters OND1 and OND2 which convert the dc power of the "low voltage" network into ac power. The inverter may in particular be capable of operating an associated electric machine.

There is also an ultra-low voltage electrical network operating on direct current at about 12 volts in the vehicle.

The battery of the so-called "low voltage" network is called traction battery BT, while the battery of the ultra-low voltage electrical network is denoted BTBT.

The two electrical networks are interconnected by means of a dc-dc converter CCC.

The on-board network RdB, to which the different electrical consumers of the motor vehicle 1 are connected (bridge), is supplied by the ultra-low voltage network.

The powertrain further comprises a commanded alternator AD which is powered by the ultra-low voltage electrical network and is coupled to the internal combustion engine MTH by means of a starter belt CAD on an attachment face of the internal combustion engine MTH, so that the energy provided by the internal combustion engine MTH can be used for powering the ultra-low voltage electrical network and charging the ultra-low voltage battery BTBT, or conversely so that the energy of this network can be used for starting the internal combustion engine MTH or braking the internal combustion engine (extracting torque) by means of the alternator AD.

The above architectures are merely examples. The invention applies in particular to architectures allowing an electric crawling function, as is the case with the motor vehicle of fig. 1.

The architecture thus has a front electric machine MELAV coupled to the front powered wheel axle TRMAV through the transmission ratio of the gearbox BV and coupled or uncoupled to the internal combustion engine MTH through the opening of the front clutch EMBAV, which is able to generate said creep function in a controlled manner.

However, when the front electric machine MELAV is not present, the architecture is provided with an alternator AD coupled to the front powered axle TRMAV and to the internal combustion engine MTH through the transmission ratio of the gearbox BV, which is able to generate said creep function in a controlled manner.

The creep torque is considered artificial and controllable by external steering functions, and can be activated or deactivated depending on the use.

The driving assistance monitor 10 responds to the driver's will expressed by means of a human-machine interface. Thus, the driver adjusts the adaptive speed regulator adapted to the target speed value, or requests the vehicle to be parked empty or randomly.

There is interest in operating points at very low speeds, such as parking until the vehicle is stopped, taking off again or an automatic parking maneuver being performed.

In fig. 2, the connection between the driving assistance monitor 10, the powertrain monitor 20 and the hydraulic brake system monitor 30 is shown.

On this figure, the drive train GMP is also shown.

The powertrain monitor 20 forms, among other functions, a determining component for determining a value of the maximum braking torque that can be delivered by the powertrain GMP. As will be mentioned below, the drive train monitor takes into account for this purpose the torque ranges that can be transmitted by the various components MTH, BV, EMB, MEL (internal combustion engine MTH, transmission BV, clutch EMB, and electric machine MEL) of the drive train GMP.

In general, the driving assistance monitor 10 and the drive train monitor 20 form a determination component for determining a command 301 to be transmitted to the drive train GMP and for applying the command 301 to the drive train GMP.

The driving assistance monitor 10 implements a calculation step E1 (for calculating the vehicle dynamics in accordance with environmental constraints, such as the distance to the surrounding vehicle or the presence of obstacles). The driving assistance monitor takes into account the initial driver set point (in particular the reference speed or the target speed) defined by the adaptive speed regulator or the human-machine interface of the automatic parking function.

At the end of this calculation step El, the driving assistance monitor 10 possesses a deceleration set point 100, which is used during an allocation step E2 (for allocating the deceleration set point between the powertrain and the hydraulic braking system). In order to perform this allocation, the driving assistance monitor 10 possesses a range of torque values to which the powertrain GMP can be applied to the powered wheels. From this value range, the driving assistance monitor 10 deduces what it can request from the drive train GMP (where the end of the transmitted torque range must not be exceeded, the action is prioritized) and what it needs to request from the brake system F.

At the end of this allocation step E2, the driving assistance monitor 10 has a deceleration set point 101 to be sent to the powertrain monitor 20 and a deceleration set point 102 to be sent to the hydraulic brake system monitor. The obtainment of these set values constitutes the preparation of the commands 301 and 302 to be sent to the powertrain GMP and to the hydraulic braking system F.

Thus, the drive assist monitor uses the maximum torque value available for braking (which is the limit of the range of brake torque values transmitted to the drive assist monitor 10 that can be transmitted by the powertrain GMP to the wheels) to adapt the brake setpoints 102 and 103 during state E2, by taking into account the maximum torque value that the powertrain can provide for braking, which the drive assist monitor then sends to the powertrain monitor 20 and the hydraulic brake system monitor 30.

Before being sent to the powertrain monitor 20, the deceleration set point 101 sent to the powertrain is converted to a torque set point during a calculation step E3 (for calculating the torque set point of the powertrain), which is also carried out by the driving assistance monitor 10. At the end of this calculation step E3, the torque setpoint 103 sent by the driving assistance system is sent from the driving assistance monitor 10 to the powertrain monitor 20.

During a consideration step E4 (for consideration of the powertrain torque set point), the powertrain monitor 20 takes into account the torque set point 103 issued by the drive assist system and the immediate state of the powertrain.

The consideration includes correcting the torque set-point 103 received from the driving assistance monitor 10 according to the information available in the powertrain monitor 20, in particular the instantaneous status of the different components of the powertrain GMP, and transmitting information to the driving assistance monitor 10 to be able to better perform the preparation of the torque set-point 103 issued by the driving assistance system.

At the end of this consideration step E4, the drive-train monitor 20 thus possesses, on the one hand, a corrected torque setpoint 105, which is the subject of subsequent consideration for the drive-train torque setpoint at the discretion of the driver, and, on the other hand, a torque value range 104 that can be accessed by the drive-train, which is sent to the drive-assist monitor 10.

The powertrain monitor 20 executes on the one hand (for adapting the acceleration set-point transmitted to the powertrain by the driver 200 taking into account the corrected torque set-point 105) the consideration step E5.

At the end of this consideration step E5, the powertrain monitor 20 possesses the coordinated torque setpoint 106. The powertrain monitor takes into account both the elements transmitted by the driving assistance function (based on algorithms and measurements performed by sensors of the vehicle) and the expressed driver request relating to the accelerator pedal.

In addition, on the right part of the figure, the driving assistance monitor 10 transmits a deceleration set value 102 to the hydraulic brake system monitor, which is sent to the hydraulic brake system monitor 30.

During a consideration step E6 performed by the hydraulic brake system monitor 30 (for taking into account the brake set value intended by the driver), the brake set value 201 expressed by the driver by pressing on the brake pedal is used to modify the deceleration set value 102 sent to the hydraulic brake system to the coordinated brake set value 107.

Subsequently, during the allocation step (for allocating the brake set value between hydraulic braking and powertrain recuperation braking), the coordinated brake set value 107 is used to express: on the one hand, the hydraulic brake set point 302 transmitted to the hydraulic brake system F, and on the other hand, the powertrain recovered energy set point 108 transmitted to the powertrain monitor 20.

At the bottom of the figure, the powertrain monitor 20 considers the recovered energy setpoint 108 (based on the coordinated torque setpoint 106) during a define step E8 (for defining setpoints for the powertrain components).

The defining step E8 (for defining the setpoints for the powertrain components) thus takes into account the coordinated torque setpoint 106 and the powertrain recovered energy setpoint 108 and results in the expression of the command 301 for the powertrain. This command 301 for the drive train is transmitted to the drive train GMP (which includes the internal combustion engine MTH, the gearbox BV, the clutch EMB and the electric machine MEL). This transmits the torque set point and the reduction ratio set point, or the opening or closing of the clutch, to these components of the powertrain.

During the definition step E8 (for defining the settings for the powertrain components), there is also an establishment of a maximum recovered energy value 109 implementable by the powertrain, which is transmitted to the hydraulic brake system monitor 30 for determination during the distribution step E7 (for distributing the brake settings between hydraulic braking and recovered braking by the powertrain). In fact, during this distribution step E7, the powertrain recovered energy setpoint 108 should not exceed the maximum recovered energy value 109 that can be implemented, which is obtained by the hydraulic brake system monitor 30 and derived from the powertrain monitor 20.

In fig. 3A, the internal operation of the powertrain monitor 20 according to the prior art is shown in more detail.

First, it is explicitly noted that the coordinated torque setpoint 106 shown on fig. 2 is calculated in two stages by using a lead-in step E5 '(for leading in the activation of the creep function) which acts on the coordinated torque setpoint 106 generated during the consideration step E5 (for taking into account the driver's intention for the torque setpoint of the drive-train). Thus, at the end of the introduction step E5' (for introducing creep function activation), the powertrain monitor 20 defines a coordinated torque set point 106b with creep, which is used during the above-mentioned definition step E8 (for defining set points for the powertrain components).

Also shown on FIG. 3A is the range of transient torques 350 that can be transmitted by the various components of the powertrain obtained by the powertrain monitor 20. These ranges 350 are obtained from the power assembly GMP. These ranges 350 are used in the powertrain monitor 20 during a summarization step E20 (for summarizing the torque producing capability of the powertrain in order to define a single instantaneous torque range 120 that can be transmitted by the powertrain).

This instantaneous torque range 120 is taken into account during the consideration step E4 (for taking into account the driving assistance setpoint for the torque setpoint of the drive train).

According to the invention, in the embodiment shown on fig. 3B, it is no longer the instantaneous torque range 120 transmitted for the execution of step E4, but on the one hand the maximum instantaneous torque value 121 that can be transmitted by the drive train and on the other hand the minimum instantaneous torque value 122 that can be transmitted by the drive train. The maximized instantaneous value 121 and the minimized instantaneous value 122 constitute the limits of the previously used instantaneous range 120.

During the consideration step E4 (for taking into account the driving assistance setpoint for the torque setpoint of the drive-train), the maximum instantaneous value 121 is directly taken into account.

Conversely, during the consideration step E21 (for taking creep into account), the instantaneous minimization value 122 is modified to constitute the instantaneous torque minimization value 123 transmittable by the drive train, modified to take into account creep. The corrected instantaneous value of minimization 123 resulting from this step is unchanged with respect to the instantaneous value of minimization 122 when the creep function is inactive, and is corrected according to the instantaneous value of torque of the creep function when the creep function is active.

The corrected minimized instantaneous value 123 is taken into account for step E4 (for taking into account the driving assistance setting for the torque setting of the powertrain).

The correction consists, for example, in replacing the instantaneous minimization value 122 by the value having the smallest absolute value of the instantaneous minimization value 122 and the instantaneous torque value of the creep function. The value so modified is the modified minimization value 123.

Thus, when creep is actually present, the torque value of the creep function is introduced into the minimized torque value that can be implemented by the powertrain. When the creep function is not active, the torque value remains unchanged (value 123 equals value 122).

The torque range 104 transmitted to the driving assistance monitor is defined by the corrected instantaneous value for minimization 123 and instantaneous value for maximization 121.

In fig. 4A, a deceleration scenario according to the prior art, but not the invention, is shown.

The curve C1 shows the vehicle speed in km/h. Curve C2 shows the activation (1) or deactivation (0) of the control request by the drive train GMP. Curve C3 shows the activation (1) or deactivation (0) of the control request by the hydraulic brake system, for example by the ESP function (electronic trajectory modifier).

The curve C4 itself shows negative torque values in Nm (in the range between 0Nm and-4000 Nm).

These curves are: the actual torque applied to the wheels 40, the torque setpoint 41 transmitted to the powertrain monitor (reference numeral 103 in fig. 2, 3A and 3B), the torque 42 of the creep function of the powertrain, and the minimum powertrain torque 43 transmitted by the powertrain monitor 20 to the driving assistance monitor 10.

At the beginning of this scenario, the horizontal speed of the vehicle is positive and a negative torque applied to the wheels causes deceleration. The creep function does not affect the torque on the wheel because the absolute value of the torque 40 applied to the wheel is less than the absolute value of the torque 42 of the creep function. Thus, the torque setpoint 41 transmitted to the powertrain monitor is successfully and faithfully implemented in the form of the torque 40 implemented onto the wheels. It is also noted that these values 40 and 41 are, in absolute value, less than the minimum torque 43 that the powertrain can produce (negative, with maximized absolute value).

Nevertheless, the torque setpoint 41 transmitted to the drive train increases in absolute value and crosses the torque value 42 of the creep function at time t 1. From this point in time, the torque 40 applied to the wheels follows the creep torque value 42, which exceeds the torque setpoint 41 transmitted to the drive train (which is no longer a faithful implementation). Saturation is discussed.

Later on, at time t2, the torque setpoint 41 transmitted to the powertrain reaches and is limited by the minimized torque value 43 of the powertrain, since the drive assist monitor knows this value. Nevertheless, this does not affect the torque 40 applied to the wheel, since this torque is always limited by the torque 42 of the creep function due to saturation phenomena. The steering is imperfect with delays in braking applications.

From the instant t3, the driving assistance monitor 10 decides to compensate for the underimplementation of said torque by means of the deceleration set point implemented by the hydraulic braking system F, as can be seen on the curve C3. The vehicle is thereby braked more strongly and more quickly. The braking is no longer actuated by the drive train GMP, as can be seen on the curve C2. The experience of the passenger and the driver is less than satisfactory and braking beyond the desired is requested.

On fig. 4B, the same scenario is shown, but implementing the invention, allowing the best coordination between the deceleration set-point and the torque value of the creep function.

Curve C1' shows speed, while curves C2' and C3' show (as described above) activation or deactivation maneuvers by the powertrain or by the hydraulic brake system F.

Curve C4' shows torque values in Nm.

Curve 50 shows the torque applied to the wheels, while curve 51 shows the torque setpoint transmitted to the powertrain monitor 20 and curve 52 shows the torque value of the creep function. The curve 53 shows the minimum torque that can be generated by the drive train GMP (known, for example, from the driving assistance monitor 10).

In this scenario, by means of the invention, the torque value of the creep function (curve 52) is coordinated with the minimum torque value (curve 53) that can be provided by the drive train GMP. This results in that the creep does not affect the faithful implementation of the braking torque setpoint, since the torque setpoint transmitted to the drive train GMP does not intersect the torque value of the creep function and remains smaller in absolute value than the torque value of the creep function.

This results in that the torque applied to the wheels (curve 50) faithfully follows the torque setpoint (curve 51) transmitted to the powertrain monitor 20, whereas at the instant t1', the hydraulic braking system F is engaged, the cumulative effect of the torque applied to the wheels being more pronounced than in the prior art, which means a better braking quality and no sudden pause (a-coup), the recuperative braking applied by said powertrain making the transition to the braking applied by the hydraulic braking system F good.

It is thus shown that the driving assistance monitor 10 can request the drive-train monitor 20 to apply the torque setpoint up to saturation of the limit of minimization of the torque that can be applied when it is not saturated, so that the setpoint is applied faithfully and the transition to the braking performed by the hydraulic brake circuit with ESP function can be carried out flexibly and without an abrupt pause.

It is explicitly noted that the driving assistance monitor 10 visible in fig. 2, 3A and 3B is incorporated in the hydraulic brake system monitor 30 in the context of an automatic parking function, and the already introduced principle is not re-discussed.

In contrast, in the adaptive adjustment function, the driving assistance monitor 10 is separated from the hydraulic brake system monitor 30 that is outside the driving assistance monitor. The driving assistance monitor thus possesses a specific computer device which may have a high computational power.

As mentioned in connection with fig. 1 and in connection with the position of the electric machine, the motor vehicle can be equipped with a hybrid powertrain of the full hybrid type (parallel hybrid with two traction motors (one traction internal combustion engine, the other traction motor)) or of the mild hybrid type (micro hybrid with a traction internal combustion engine assisted by an auxiliary motor/auxiliary generator, which has a power too low to implement the traction of the vehicle on its own).

The vehicle's power battery (the "low voltage" battery BT visible on fig. 1) may be charged on the external network by means of a wired or inductive connection, or not charged except for the regeneration obtained via the motor/generator. The vehicle may also be a battery-powered electric vehicle or a fuel cell-powered electric vehicle.