EP1753635B1 - Device and method for controlling torque applied to wheels of a vehicle - Google Patents

Abstract

A motor vehicle power train control device capable of furnishing set signals of torque applied to wheels of the motor vehicle. The control device includes a mechanism to generate a signal representing a limitation of variation in speed of a heat engine integrated in a power train capable of reducing variations that are disturbing with regard to acoustics of the power train, and includes a mechanism to determine an operating point of the power train in an optimal operating range according to the signal that represents limitation of speed. The mechanism for generating the signal that represents a limitation of variation in the speed of the heat engine integrated in the power train is furnished, at an input, by parameters that represent characteristics of the motor vehicle and by parameters that represent the driver's wishes.

Description

The present invention relates to a control device of a powertrain unit capable of delivering torque setpoint signals to be applied to the motor vehicle wheels, and a related method.

The invention more particularly relates to a control device of a powertrain, which can be adapted to any type of motor vehicle and to control the variations of the engine speed of said group to improve the acoustics felt by the driver and the passengers of the motor vehicle.

At the present time, in order to obtain a particularly satisfactory driving pleasure, it is sought to reduce as much as possible the noise nuisance caused by the motor-drive unit of the motor vehicle.

To this end, the applicant has developed a device for controlling the operating point of a powertrain of the motor vehicle, described in document FR-A-2,827,339 . The control carried out by this device is a torque control applied to the wheels of the motor vehicle. The value of the torque to be applied to the wheels of the motor vehicle, is calculated directly at the wheels of the motor vehicle. Such a device is equipped with a module for interpreting the driver's will, said module IVC, comprising in particular a generator for generating a signal representative of a limitation of variation of the speed of the powertrain group capable of reducing variations. acoustics of the powertrain that the driver is likely to hear.

Said signal is transmitted to an optimization unit of the power unit for controlling the torque to be applied to the wheels of the vehicle, the optimization block for determining an operating point in an optimal operating range of the powertrain on the basis of driving pleasure constraint. The determination of the signal representative of a limitation of the speed of the powertrain group capable of reducing the acoustically inconvenient variations of the powertrain unit is carried out according to the degree of activity of the driver and the speed of the motor vehicle.

Such a device, able to improve the acoustics felt by the people within the cabin, has the drawback of not allowing to correctly take into account the torque demand variations to be applied to the wheels, the signal being determined mainly by the speed of the motor vehicle.

The object of the present invention is therefore to overcome this drawback and to provide a device for controlling a powertrain that can take into account, in a particularly precise manner, the variations in torque demand, and therefore indirectly the speed of the power unit. thruster, making it possible to determine the limitations of the adapted powertrain group.

For this purpose, the control device of a motor-drive unit of a motor vehicle capable of delivering torque command signals to be applied to the wheels of the motor vehicle comprises means for generating a signal representative of a limitation of variation of the speed of the heat engine integrated in the powertrain capable of reducing the acoustically annoying variations of said group, and means for determining an operating point of the powertrain in a Optimum operating range of the power train according to the representative speed limitation signal. The means for generating the signal representative of a limitation of variation of the speed of the engine integrated in the powertrain is input fed by parameters representative of the characteristics of the motor vehicle and parameters representative of the will of the driver.

The torque instruction to be applied to the wheels is calculated directly at the wheels of the motor vehicle.

With such a device, it thus becomes possible to provide a device for determining the operating range of the powertrain for driving approval directly adapted to the will of the driver issued, including through the accelerator pedal. The device thus makes it possible to have an acoustics of the powertrain unit dependent not only on the speed of the motor vehicle, but also on the will of the driver. In other words, the device makes it possible to take into account the variations in the position of the accelerator pedal in order to generate speed limits for the engine of the powertrain, in addition to the acceleration or the deceleration of the vehicle.

The parameters representative of the characteristics of the motor vehicle may comprise a parameter representative of the estimated or measured degree of activity of the driver Acond, and a parameter representative of the speed of the motor vehicle Vveh.

Preferably, the parameters representative of the driver's will include parameters representative of the position of the Pedacc accelerator pedal and the parameters representative of the position of the Pedfrein brake pedal. Advantageously, Parameters representative of the will of the driver further include a parameter representative of the gradient of the position of the accelerator Pedacc_grd pedal .

In one embodiment, the parameter representing the gradient of the position of the accelerator pedal Pedacc_grd has been filtered by a filtering means and / or timed by a delaying means before the generation means are fed by said parameter Pedacc_grd .

$$\mathit{lim\_var\_rpm\_pos}=\mathrm{F}2\left(\mathit{Acond},,\mathit{Vveh}\right)$$

dans lesquelles les fonctions variables F1 et F2 dépendent de la position de la pédale d'accélérateur et du gradient de la position de ladite pédale, lesdites fonctions étant déterminées par des tables d'interpolation dont les paramètres sont déterminés de manière définitive lors de la mise au point du véhicule.The generating means advantageously produces two limiting signals lim_var_rpm_pos, lim_var_rpm_neg defined by the relations: $$\mathit{lim\_var\_rpm\_pos}=\mathrm{F}1\left(\mathit{acond},,\mathit{Vveh}\right)$$

$$\mathit{lim\_var\_rpm\_pos}=\mathrm{F}2\left(\mathit{acond},,\mathit{Vveh}\right)$$

in which the variable functions F1 and F2 depend on the position of the accelerator pedal and the gradient of the position of said pedal, said functions being determined by interpolation tables whose parameters are determined definitively when setting at the point of the vehicle.

The invention also relates to a method for controlling a motor-driven power unit for a motor vehicle capable of delivering torque command signals to be applied to the wheels of the motor vehicle, in which a signal representative of a limitation of the speed of the motor vehicle is generated. a heat engine integrated in the power unit capable of reducing the acoustically annoying variations of said group, an operating point of the power unit is determined in an optimal operating range of the power unit according to the signal representative of speed limitation. This signal is generated representative of a limitation of variation of the speed of the integrated heat engine. powertrain group according to input parameters representative of the characteristics of the motor vehicle and parameters representative of the will of the driver.

Advantageously, a limitation of the speed of the heat engine integrated in the power unit is generated as a function of the depression of the Pedacc accelerator pedal . Said limitation may also be generated as a function of the depression of the vehicle brake and / or according to the gradient of the position of the accelerator pedal Pacc_grd.

• on compare l'enfoncement de la pédale d'accélération à un premier seuil de position prédéterminé correspondant à un état d'enfoncement au-delà du point dur de la pédale d'accélérateur,
• on compare l'enfoncement de la pédale d'accélération à un second seuil de position prédéterminé correspondant à un état d'enfoncement important de la pédale mais inférieur au premier seuil,
• on compare l'enfoncement de la pédale d'accélération à un troisième seuil de position prédéterminé correspondant à un état d'enfoncement de la pédale inférieur au second seuil,
• on compare le gradient d'enfoncement de la pédale d'accélération à un quatrième seuil de variation de position prédéterminé correspondant à un enfoncement rapide de ladite pédale,
• on compare le gradient d'enfoncement de la pédale d'accélération à un cinquième seuil de variation de position prédéterminé correspondant à un relèvement rapide de ladite pédale,

chaque étape déterminant une limitation du régime du moteur thermique entre des valeurs limites de fonctionnement ou autorisant l'étape suivante selon la valeur des paramètres.In one embodiment, limiting the speed of the heat engine integrated in the powertrain comprises at least one of the following steps:

• the depression of the accelerator pedal is compared to a first predetermined position threshold corresponding to a driving state beyond the hard point of the accelerator pedal,
• comparing the depression of the accelerator pedal with a second predetermined position threshold corresponding to an important depression state of the pedal but lower than the first threshold,
• comparing the depression of the accelerator pedal with a third predetermined position threshold corresponding to a depression state of the pedal lower than the second threshold,
• comparing the depression gradient of the accelerator pedal with a fourth predetermined position variation threshold corresponding to a rapid depression of said pedal,
• comparing the depression gradient of the accelerator pedal with a fifth predetermined position variation threshold corresponding to a rapid raising of said pedal,

each step determining a limitation of the engine speed between operating limit values or allowing the next step depending on the value of the parameters.

• la figure 1 est un schéma bloc d'un dispositif de commande selon la présente invention,
• la figure 2 est un schéma bloc d'un moyen de génération d'un signal du dispositif de commande de la figure 1, et
• la figure 3 illustre schématiquement les différents étapes de fonctionnement d'un moyen de génération de la figure 2.

The invention and its advantages will be better understood when studying the description of a non-limiting embodiment, and illustrated by the appended drawings in which:

• the figure 1 is a block diagram of a control device according to the present invention,
• the figure 2 is a block diagram of a means of generating a signal of the control device of the figure 1 , and
• the figure 3 schematically illustrates the different operating steps of a means of generating the figure 2 .

On the figure 1 there is shown a control device comprising a means 1 for interpreting the driver's will, a means 2 for determining an operating point in an optimum operating range of a powertrain 3 and an embodiment 4 the determined operating point.

The means 1 is connected to three input modules 5, 6 and 7, respectively via connections 8, 9 and 10, able to produce a signal representative of a quantity measured by sensors (not shown) mounted on the vehicle.

The module 5 provides the characteristics of the vehicle, in particular the vehicle behavior profiles programmed by the manufacturer to characterize the behavior of the vehicle delivered to a customer. The module 6 is capable of developing data by providing the interface between the human driver and the rest of the motor vehicle according to the technique of man / machine interfaces. The module 7 is able to develop signals concerning the environment of the motor vehicle. These make it possible to take into account the state of the vehicle and its location in the environment, such as the speed of the motor vehicle, the condition of the roadway or the weather conditions. The value of the parameters and the state of the variables of the input data transmitted by these three modules can be stored in a common memory for each element of the device (not shown).

The means 1 comprises a torque setpoint generator 11 to be applied to the wheels comprising a static component, called the static torque Cs , and a torque setpoint generator 12 to be applied to the wheels comprising a dynamic component, called the dynamic torque Cd. Such generators torque setpoint can be for example generators as described in the application FR-A-2,827,339 .

The means 1 also comprises a generator 13 for limiting the speed variation of the heat engine of the power unit capable of generating two limiting setpoint signals 21, 22, called the positive limit of the speed lim_var_rpm_pos, in order to limit the speed variations towards the direction of the increase, and limit of negative regime lim_var_rpm_neg to limit the variations of the engine speed in the direction of the reduction. The speed variation limitation defines the variation of the engine speed during a determined time interval.

As illustrated in figure 2 , the generation means 13 receives as input data representative of the will of the driver as well as data representative of the characteristics of the motor vehicle.

• Pedacc : l'information représentative de l'état d'enfoncement de la pédale d'accélérateur du véhicule, par l'intermédiaire d'un capteur (non représenté),
• Pedacc_grd : le gradient de la position de la pédale d'accélérateur à partir de l'état d'enfoncement de la pédale d'accélérateur par rapport à un état d'enfoncement précédent, ledit gradient étant calculée par l'intermédiaire d'un opérateur spécifique (non représenté) calculant une dérivée de positions successives de la pédale d'accélérateur,
• Kick : l'enfoncement de la pédale d'accélérateur au-delà d'une butée physique appelée aussi point dur de l'accélérateur, pouvant notamment permettre, sur une transmission automatique de type conventionnelle à rapport discrets, de forcer le rétrogradage au rapport inférieur afin d'obtenir un surcroît d'accélération momentané pouvant être nécessaire par exemple lors d'un dépassement,
• Pedfrein : l'information représentative de l'état d'enfoncement de la pédale de frein du véhicule, par l'intermédiaire d'un capteur (non représenté).

The data representative of the will of the driver, respectively transmitted by the connections 14, 15a, 16 and 17, are:

• Pedacc: information representative of the state of depression of the accelerator pedal of the vehicle, via a sensor (not shown),
• Pedacc_grd: the gradient of the position of the accelerator pedal from the depression state of the accelerator pedal relative to a preceding driving state, said gradient being calculated via an operator specific (not shown) calculating a derivative of successive positions of the accelerator pedal,
• Kick : the depression of the accelerator pedal beyond a physical stop, also known as the hard point of the accelerator, which may in particular make it possible, on a conventional automatic transmission with a discrete ratio, to force the downshift to the lower gear in order to obtain an additional momentary acceleration which may be necessary, for example during an overrun,
• Pedfing : the information representative of the state of depression of the brake pedal of the vehicle, via a sensor (not shown).

The data representative of the gradient of the accelerator pedal can advantageously be filtered by a filtering means 20, such as a filter, before being transmitted by the connection 15b to the generating means 13 in order to eliminate any unwanted noise. It is also conceivable to provide a timing means (not shown) capable of storing a maximum value of the gradient of the position of the pedal during a given period of time to transmit it to the generation means 13.

• Acond : le degré d'activité du conducteur (en %) estimé ou mesuré, pouvant être lu dans la mémoire enregistrant l'activité du conducteur,
• Vveh : la vitesse du véhicule (en km/h), pouvant être lue ou interprétée sur les mémoires ou variables d'état représentant des signaux représentant la vitesse du véhicule.

The data representative of the characteristics of the motor vehicle, transmitted respectively by the connections 18 and 19 are:

• Acond: the degree of activity of the driver (in%) estimated or measured, readable in the memory recording the activity of the driver,
• Vveh: the speed of the vehicle (in km / h), which can be read or interpreted on the memories or state variables representing signals representing the speed of the vehicle.

On the basis of the data received at the input, the generating means 13 makes it possible to determine the speed variation limitation in order to improve the acoustics within the passenger compartment of the motor vehicle, by transmitting the setpoint signals for limiting variations in the speed of the vehicle. speed towards the direction of the increase lim_var_rpm_pos and limiting the speed towards the direction of the reduction lim_var_rpm_neg , respectively by the connections 21 and 22, by means of determination 2 of the operating point of the power unit.

The organization chart shown on the figure 3 , shows the various tests of analysis and comparison made on the data transmitted by the connections 14 to 19 ( figure 2 ). These tests are carried out by different comparison means, for example comparators, according to the following process.

A first step 23 consists in determining whether the accelerator pedal is depressed beyond a first threshold, here beyond the hard point of the so-called kick accelerator. If the depression of the accelerator pedal PedAcc is greater than the depression corresponding to the hard point kick then the generation means 13 chooses a first mode 24 in which the variable lim_var_rpm_pos takes the calibrated value Ni_grd_max and the variable lim_var_rpm_neg takes the value calibrated Ni_grd_min, where Ni represents a speed setpoint of the engine integrated in the powertrain 3 ( figure 1 ), predetermined in order to obtain a limitation of the operating point to achieve the maximum performance of said powertrain 3 while having improved acoustics for people inside the passenger compartment of the motor vehicle.

If the depressing of the accelerator pedal is less than the depression corresponding to the hard point kick then the generating means 13 goes to step 25 and checks whether the depression of the accelerator pedal Pedacc is greater than one. seuil_PedaccF second threshold corresponding to a depression of the accelerator pedal close to 100%, being for example 95%. If the depression of the acceleration pedal of the motor vehicle is strictly greater than the predetermined threshold of depression of the accelerator pedal ( Pedacc> threshold_PedaccF ) then the generation means 13 goes to a second mode 26 in which the variable lim_var_rpm_pos is calculated from a calibratable mapping p_PedaccF and lim_var_rpm_neg variable is calculated from a calibratable mapping n_PedaccF. These two maps depend on the activity information of the driver Acond and the speed of the motor vehicle Vveh respectively transmitted by the connections 18 and 19 ( figure 2 ), said Acond and Vveh data being respectively read or interpreted on the memory recording the profile of the driver, and on the memory or state variables representing signals describing the environment of the vehicle.

If the depression of the accelerator pedal is less than the recess corresponding to the second threshold then the seuil_PedaccF generation means 13 proceeds to step 27 and checks whether the depression of the Pedacc accelerator pedal is less than a seuil_PedaccL third threshold corresponding to a depression of the accelerator pedal close to 0%, being for example 10%. If the depression of the acceleration pedal of the motor vehicle is strictly less than the predetermined threshold of depression of the accelerator pedal ( Pedacc <threshold _ PedaccL ) then the generation means 13 goes to a third mode 28 in which the variable lim_var_rpm_pos is calculated from a calibratable mapping p_PedaccL and lim_var_rpm_neg variable is calculated from a calibratable mapping n_PedaccL. These two maps depend on the activity information of the driver Acond and the speed of the motor vehicle Vveh.

If the depression of the accelerator pedal is greater than the third PedaccL threshold then the generation means 13 goes to step 29 and checks whether the filtered gradient of the depression of the Pedacc_grd_fil accelerator pedal is greater than a fourth. PeduccFD threshold corresponding to a rapid depression of the accelerator pedal without however the position of the accelerator pedal reaches the second threshold threshold _ PedAccF . If the gradient of the position of the accelerator pedal of the motor vehicle is strictly greater than the predetermined threshold (Pedacc _ _ grd thread> _ PedaccFD threshold) then the generation means 13 proceeds to a fourth embodiment 30 wherein the variable is lim_var_rpm_pos calculated from a calibratable mapping p_PedaccFD and lim_var_rpm_neg variable is calculated from a calibratable mapping n_PedaccFD. These two maps depend on the activity information of the driver Acond and the speed of the motor vehicle Vveh.

If the gradient of the position of the accelerator pedal is less than the fourth threshold seuil_PedaccFD then the generation means 13 proceeds to step 31 and checks whether the filtered gradient of depression of the accelerator pedal is less than Pedacc_grd_fil fifth seuil_PedaccLD threshold corresponding to a quick survey of the accelerator pedal without reaching the second threshold seuil_PedaccL. If the gradient of the position of the acceleration pedal of the motor vehicle is strictly less than the predetermined threshold ( Pedacc_grd_fil <threshold_PedaccLD ) then the generation means 13 passes to a fifth mode 32 in which the variable lim_var_rpm_pos is calculated from a calibrable map p_PedaccLD and the variable lim_var_rpm_neg is calculated from a calibrable map n_PedaccLD. These two maps depend on the activity information of the driver Acond and the speed of the motor vehicle Vveh.

If the gradient of the position of the acceleration pedal of the motor vehicle is greater than the predetermined threshold ( Pedacc_grd_fil> threshold_PedaccLD ) then the generation means 13 goes to a sixth mode 33 in which the variable lim_var_rpm_pos is calculated from a map calibrable p_PedaccS and the variable lim_var_rpm_neg is calculated from a calibrated map n_PedaccS. These two maps depends on the information of the activity Acond driver and the speed of the vehicle Vveh, and correspond to an average position of the pedal between the second threshold and the third seuil_PedaccF seuil_PedaccL threshold.

The generating means 13 thus makes it possible to transmit a limitation of the variation of the speed of the heat engine by means of determination 2 in order to improve the acoustics within the passenger compartment of the motor vehicle, by transmitting the control signals of limitation of the variations. the speed of the engine in the direction of the increase Iim_var_rpm_pos and limitation of the speed in the direction of the reduction lim_var_rpm_neg , by means of determination 2. Said variable limiting signals thus take into account the variations in the torque demand generated at from the Pedacc accelerator pedal.

It is also possible to use in a similar way the depression position of the Pedfrein brake pedal from the information transmitted by the connection 17 ( figure 2 ) by means of generation 13 or to stop the limitation of variations of the speed when the driver depresses the Pedfrein brake pedal.

As illustrated on the figure 1 the determining means 2 also receives a static torque setpoint Cs of the generator 11 via the connection 34 and a static torque setpoint Cd of the generator 12 via the connection 35.

The means 2 for determining the operating point of the power unit 3 thus receives four control signals lim_var_rpm_pos, lim_var_rpm_neg, Cs and Cd. The determination means 2 thus allows the independent parameterization of the modules 36, 37 and 38 which constitute it, the module 36 delivering a torque signal to the wheel C , the module 37 a battery power signal Pbat, and the module 38 a motor speed control signal N. Said signals are transmitted, respectively via the connections 39, 40 and 41, to the module 4 for producing the operating point of the power unit 3 for controlling the control members of the power unit 3 by means of of the connection 42 and the drive wheels 43 by the connection 44 in a manner similar to the patent application FR-A-2,827,339 in the name of the plaintiff.

The present invention thus makes it possible to carry out a control applied to the wheel of the operating point of the power unit making it possible to generate speed limit setpoints for said engine integrated in the powertrain group that are directly dependent on the state of the vehicle but also adapted to the the driver's will, including through the accelerator pedal, for the purpose of obtaining improved driving pleasure.

Claims (8)

1. Device for controlling a power train of a motor vehicle suitable for delivering set-point signals of torque to be applied to the wheels of the motor vehicle, comprising a means (1) of generating a signal representative of a limitation of variation in the speed of the heat engine incorporated in the power train suitable for reducing the variations that are disturbing from an acoustic point of view of said power train, and a means (2) of determining an operating point of the power train in an optimal operating range according to the signal representative of speed limitation, the means (1) of generating the signal representative of a limitation of variation in the speed of the heat engine incorporated in the power train being fed as input with parameters representative of the characteristics of the motor vehicle, and parameters representative of the wishes of the driver, including parameters representative of the position of the accelerator pedal (Pedacc), parameters representative of the position of the brake pedal (Pedfrein), and a parameter representative of the gradient of the position of the accelerator pedal (Pedacc_grd), characterized in that the generation means (1) produces two power train operating limit values (lim_var_rpm_pos, lim_var_rpm_neg) that are variable and dependent on the position of the accelerator pedal and the gradient of the position of said pedal relative to predetermined thresholds.
2. Device according to Claim 1, characterized in that the parameters representative of the characteristics of the motor vehicle comprise a parameter representative of the estimated or measured degree of activity of the driver (Acond), and a parameter representative of the speed of the motor vehicle (Vveh).
3. Device according to Claim 1 or 2, characterized in that the parameter representative of the gradient of the position of the accelerator pedal (Pedacc_grd) has been filtered by a filtering means before feeding the generation means (1) with said parameter (Pedacc_grd).
4. Device according to any one of the preceding claims, characterized in that the operating limit values (lim_var_rpm_pos, lim_var_rpm_neg) are defined by the relations: $$\mathrm{lim\_var\_rpm\_pos}=\mathrm{F}1\left(\mathrm{Acond},\mathrm{Vveh}\right)$$

   

   $$\mathrm{lim\_var\_rpm\_neg}=\mathrm{F}\mathrm{2}\left(\mathrm{Acond},\mathrm{Vveh}\right)$$

   

   
   in which the variable functions F1 and F2 depend on the position of the accelerator pedal and on the gradient of the position of said pedal, said functions being determined by interpolation tables, the parameters of which have been determined definitively when tuning the vehicle.
5. Method of controlling a motor vehicle power train suitable for delivering set-point signals of torque to be applied to the wheels of the motor vehicle, in which there is generated a signal representative of a limitation of the speed of the heat engine incorporated in the power train suitable for reducing the variations that are disturbing from an acoustic point of view of said power train, an operating point of the power train is determined in an optimal operating range according to the signal representative of speed limitation, said signal representative of a limitation of variation of the speed of the heat engine incorporated in the power train is generated according to input parameters representative of the characteristics of the motor vehicle and parameters representative of the wishes of the driver, characterized in that the limitation of the speed of the heat engine comprises at least one of the following steps:

   - the depression of the accelerator pedal is compared to a first predetermined position threshold corresponding to a depression state beyond the hard point of the accelerator pedal,

   - the depression of the accelerator pedal is compared to a second predetermined position threshold corresponding to a depression state of the pedal less than the first threshold,

   - the depression of the accelerator pedal is compared to a third predetermined position threshold corresponding to a depression state of the pedal less than the second threshold,

   - the depression gradient of the accelerator pedal is compared to a fourth predetermined position variation threshold corresponding to a fast depression of said pedal,

   - the depression gradient of the accelerator pedal is compared to a fifth position variation threshold corresponding to a rapid release of said pedal,

   each step determining a limitation of the speed of the heat engine between operating limit values or authorizing the next step according to the value of the parameters.
6. Method according to Claim 5, characterized in that a limitation of the speed of the heat engine incorporated in the power train is generated according to the depression of the accelerator pedal (Pedacc).
7. Method according to Claim 5 or 6, characterized in that a limitation of the speed of the heat engine incorporated in the power train is generated according to the depression of the brake pedal (Pedfrein)
8. Method according to one of Claims 5 to 7, characterized in that a limitation of the speed of the power train is generated according to the gradient of the position of the accelerator pedal (Pedacc_grd).

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