FR2927871A1 - Power train controlling system for hybrid vehicle, has control unit for controlling speed of wheel and determining torque setpoint of power train based on reception of logic signal from determining unit - Google Patents

Abstract

A control system for a motor vehicle power train (34) comprising at least two electric machines, at least one heat engine and an infinitely variable transmission mechanically connected to the electric machines and the heat engine. The control system comprises sensors (1); a vehicle situation determination means (17) capable of detecting wheel slip; and wheel speed control means (11) for determining torque setpoints of the powertrain (34) on receipt of a logic signal from the vehicle situation determining means (17).

Description

PATENT APPLICATION B07-1548FR Société par Actions Simplifiées known as: RENAULT sas System and process for controlling the powertrain of a vehicle equipped with infinitely variable transmission Invention of: CLAEYS Xavier KEFTI-CHERIF Ahmed MARSILIA Marco POGNANT-GROS Philippe System and powertrain control method of a vehicle equipped with infinitely variable transmission

The present invention relates to the management of powertrains, and the control of the stability of a vehicle. More particularly, the present invention relates to sliding vehicle control. Infinitely variable transmissions have found particular growth with hybrid vehicles. Indeed, the infinitely variable transmissions offer the possibility of modulating or increasing the torque delivered by a main power source by varying the pairs delivered by two secondary power sources. In the case of a hybrid vehicle, the main driving source is a heat engine, or internal combustion engine, and the secondary drive sources are generally electric machines that can operate as an electric motor or regenerative braking system. Thus equipped, a hybrid vehicle is capable of simulating a gearbox by modulating the torque provided by the internal combustion engine while maintaining an optimum operating speed, generally a low speed to limit pollutant emissions and fuel consumption. fuel. However, under slip conditions, an infinitely variable transmission runaway is possible, potentially leading to a potentially dangerous situation. There is thus a need for an infinitely variable transmission control system for correcting a wheel slip situation of a vehicle.

The present invention relates to a system and method for controlling an infinitely variable transmission for limiting the sliding of a wheel. The present invention also relates to a system and a method for controlling an infinitely variable transmission for managing the transition between a sliding situation and a normal situation. According to one aspect of the invention, there is defined a control system of a motor vehicle powertrain comprising at least two electric machines, at least one heat engine and an infinitely variable transmission mechanically connected to the electrical machines and the heat engine. The control system includes sensors; vehicle situation determining means capable of detecting wheel slip; and wheel speed control means adapted to determine torque setpoints of the powertrain upon receipt of a logic signal from the vehicle situation determining means. The control system makes it possible to detect a slip situation of a wheel and to determine torque setpoints of the powertrain for reducing the slip detected. The control system may further include switching means and nominal control means. The switching means is adapted to selectively direct the signals from the wheel speed control means and the nominal control means to the power unit according to the situation logic signal output from the vehicle situation determination means. . In this variant, the control system can be autonomous and able to determine the torque setpoints of the powertrain in the nominal or slip situations. The control system may also include stimulus control means. The switching means is then capable of selectively directing the signals from the wheel speed control means, the nominal control means and the restart control means to the power unit according to the logical situation signal transmitted by the means of determining the situation of the vehicle. In this other variant, the control system comprises a stimulus control means which makes it possible to gradually increase the drive of the wheel having undergone sliding. In other words, and whatever the variant, the switching means makes it possible to filter the signals coming from the means for controlling the speed at the wheel, the nominal control means and the stimulus control means. According to the situation detected by the means of determining the situation of the vehicle, the signal corresponding to the situation is transmitted to the powertrain. The control system may comprise a means for calculating the sliding regulation setpoints, able to determine a setpoint of the rotational speed of the wheel and a torque setpoint for the recovery wheel as a function of the signals received from the sensors and the control means. determination of the situation of the vehicle. The control system may comprise a means for calculating the nominal operating instructions, able to determine the power setpoint to be supplied by the battery, the rotation speed setpoint of the heat engine and the torque setpoint to the wheel. The wheel speed control means may be able to determine the torque setpoints of the powertrain according to the power setpoint to be supplied by the battery, the rotational speed setpoint of the engine determined by the means of the engine. calculation of the nominal operating instructions and as a function of the rotational speed of the wheel determined by the means for calculating the slip control instructions.

The stimulus control means may be able to determine the torque setpoints of the powertrain according to the power setpoint to be supplied by the battery, the setpoint of the rotational speed of the engine determined by the means for calculating the instructions. of nominal operation and as a function of the torque setpoint at the recovery wheel determined by the means for calculating the slip control instructions. The nominal control means may be able to determine the torque setpoints of the powertrain according to the power setpoint to be supplied by the battery, the reference speed of the engine and the torque setpoint to the wheel determined by the means for calculating nominal operating instructions. According to another aspect of the invention, there is defined a control method of a powertrain of a motor vehicle comprising at least two electric machines, at least one heat engine and an infinitely variable transmission mechanically connected to the electric machines and the heat engine. The method comprises: a detection step, during which at least one slip index of a wheel is determined; a comparison step, during which said slip index is compared with a stored slip threshold to determine if said wheel is in a slip situation; a determination step, during which torque setpoints of the electrical machines and the heat engine are determined according to the wheel situation. The control method may furthermore comprise, between the comparison and determination steps, a second comparison step during which said slip index is compared with a memorized restart threshold in order to determine whether said wheel is in a situation. nominal. The control method may comprise, between the comparison and determination steps, a third comparison step during which said sliding index is compared with a memorized restart threshold in order to determine whether said wheel is in a recovery situation. . It is possible to determine a power setpoint to be supplied by the battery, a setpoint for the rotational speed of the engine and a setpoint torque to the wheel if the vehicle is in a nominal situation. It is possible to determine a power setpoint to be supplied by the battery, a reference of the rotational speed of the engine and a setpoint of the rotational speed of the wheel if the vehicle is in a sliding situation. It is possible to determine a power setpoint to be supplied by the battery, a reference of the rotational speed of the engine and a torque setpoint to the recovery wheel if the vehicle is in a recovery situation. The torque setpoints of the electrical machines and the heat engine can be determined as a function of the power setpoint to be supplied by the battery, the reference value of the rotational speed of the heat engine and the torque setpoint to the recovery wheel. Other objects, features and advantages of the invention will become apparent on reading the following description, given solely by way of nonlimiting example and with reference to the appended drawings, in which: FIG. 1 illustrates the main elements included in FIG. a control system; and FIG. 2 illustrates the main steps of a control method. In FIG. 1, a SYS control system can be seen comprising means 4 for calculating the slip control instructions, a means for calculating the nominal operating instructions, a means for controlling the speed of the wheel, an stimulus control means 12, nominal control means 13, vehicle situation determination means 17 and switching means 30. Furthermore, the SYS control system interacts with other vehicle systems, in particular, sensors 1 and a power train 34. The calculation means 4 of the sliding control instructions is connected at input to the sensors 1 via connections 2 and 3, and by means 17 for determining the vehicle situation via a connection. 7, at the output by means of control 11 of the speed at the wheel by a connection 6 and the control means 12 of recovery by a connection 8.

The means 5 for calculating the nominal operating instructions is connected at the output to the nominal control means 13 via a connection 9, to the control means 12 for restarting by a bypass 10 of the connection 9 and to the control means 11 for controlling the speed. the wheel by a branch 15 of the connection 10.

The means for determining the situation of the vehicle is also connected at the output to the wheel speed control means by a bypass 16 of the connection 7, by the control means 12 for restarting by a bypass 18 of the connection 7. and by the switching means 30 via a connection 20, and at the input to the sensors 1 via a connection 19. The switching means 30 is connected at input to the wheel speed control means 11 via connections 21, 22 and 23 by means of the control 12 of stimulus by connections 24, 25 and 26, and the control means 13 nominal by connections 27, 28 and 29. The switching means 30 is connected to the output powertrain 34 by connections 31 The means 17 for determining the vehicle situation receives as input the vehicle speed Vref and the speed of rotation of the wheels 8r, a sliding threshold value S1 and a stimulus threshold value S3. The means 17 for determining the vehicle situation then determines the slip ratio value SX: r Br ù Vref Vref with r a stored value of the wheel radius. This value SX is then compared with the values S1 and S3 to determine the situation of the vehicle. Three situations can thus be detected, a nominal situation, a recovery situation or a slip situation. According to the situation detected, a logical situation signal is emitted by the outputs of the determination means 17 of the situation of the vehicle to the switching means 30, the wheel speed control means 11, the control means 12 of stimulus and calculation means 4 slip control instructions.

The calculation means 4 of the sliding regulation instructions receives as input the vehicle speed Vref, the speed of rotation of the wheels Gold and the logical situation signal. In the nominal situation, the calculation means 4 of the slip regulation instructions emit no value, the operation of the vehicle being regulated by the calculation means 5 of the nominal operating instructions and the nominal control means 13. In sliding situation, a reference value WOref of the rotational speed of the wheel is determined. W0 ref = (1 + S2) • Vref S2 is a parameter that can be memorized or determined according to variables selected in particular from the following variables, the depression of the accelerator pedal, the steering wheel angle, the sign of the slip derivative, the reference speed, .... In the recovery situation, a value TOrel (n) of torque to the stimulus wheel is determined. T0_rel (n) = T0_rel (n -1) + At • Kra pe with At = the sampling period, Krampe a ramp slope. The ramp slope gradually increases the torque to the wheel so that the stability of the vehicle is maintained. The calculation means 5 nominal operating instructions determines a value Wice reference ref of the speed of rotation of the engine and a reference value Pbat_ref of the power to be provided by the battery. The calculation means 5 nominal operating instructions can determine these values according to the data provided by the sensors 1 (the connection is not shown in Figure 1). However, the calculation means 5 nominal operating instructions can also receive these values of a means outside the SYS control system, for example a means of optimizing the operating point of the powertrain. The means of control 11 of the speed at the wheel determines the instructions of the drive members in sliding phases. In such a situation, the wheel speed control means 11 receives a reference value Wice_ref of the speed of rotation of the heat engine and a reference value Pbat_ref of the power to be supplied by the battery. The wheel speed control means 11 additionally receives a value WOref determined by the calculation means 4 of the slip regulation instructions. It is interesting to note that the aim is to satisfy the rotation speed regulation of the wheel and not the torque setpoint at the wheel as is the case conventionally in situations involving no sliding. The wheel speed control means 11 applies the following equation to determine the torque setpoints TE1, TE2 and TICE as a function of the values Wice_ref, Pbat_ref and rwel + K, = K1 2 • we2 kinematics and electrical of the transmission; and wel and we2 the rotational speeds of the first and the second electric machine

The stimulus control means 12 controls the torque at the wheel in the recovery phases. In other words, the stimulus control means 12 ensures the transition when the slip becomes small again between the assisted mode provided by the control means 11 of the wheel speed and the nominal mode of the nominal control means 13.

To achieve this goal, the stimulus control means 12 compares the torque value TOrel (n) with the stimulus wheel and the request WOref. TE 1 TE2 TICE with K'l and WOref Pbat_ref Wice ref K2 two matrices dependent on the torque parameters at the TOeq wheel. The torque setpoint to the wheel TOref held by the stimulus control means 12 is the smaller of the two values.

In a second step, the restart control means 12 determines the torque setpoints TE1 of the first electric machine, TE2 of the second electric machine and the ROD of the heat engine as a function of the torque setpoint at the wheel TO_ref, of the value Wice ref reference of the speed of rotation of the engine and the reference value Pbat_ref of the power to be provided by the battery. For this, the stimulus control means 12 applies the following equation:

TE1 TOref [wel] TEZ = K1 • + K2 • Pbat_ref (Eq. 1) we2 TICE Wice ref with K1 and K2 two matrices depending on the kinematic and electrical parameters of the transmission; and wel and we2 the rotational speeds of the first and the second electric machine

The nominal control means 13 determines the torque setpoints of the driving members of the powertrain in rated speed. For this purpose, it applies the relation (Eq.1) to the values received from the calculation means 5 of the nominal operating instructions.

The switching means 30 receives the torque setpoints TE1 from the first electrical machine, TEZ from the second electrical machine and the ROD of the heat engine from the wheel speed control means 11 via the connections 21, 22 and 23, originating from 12 of the control means 12 by the connections 24, 25 and 26 and from the nominal control means 13 by the connections 27, 28 and 29. Based on the logic signal received from the determination means 17 of the situation of the vehicle by the connection 20, the switching means 30 transmits torque setpoints TE1 of the first electrical machine, TEZ of the second electrical machine and TICE of the heat engine by the connections 31, 32 and 33 towards the powertrain 34. If the logic signal received indicates a sliding phase, the instructions from the means of control 11 of the wheel speed are transmitted by the switching means 30 towards the powertrain 34. If the received logic signal indicates a restart phase, the instructions from the restart control means 12 are transmitted by the switching means 30 towards the powertrain 34. If the received logic signal indicates a nominal phase, the instructions from the means of nominal control 13 are transmitted by the switching means 30 towards the power unit 34.

In Figure 2 we can see the main steps of a control method according to the invention. The method starts with step 35 during which a detection of the vehicle running conditions, including the vehicle speed and the speed of rotation of the wheels is performed. The slip index Sx is then determined in step 36. In step 37, the setpoints Pbat_ref and Wice_ref are determined. The method continues with step 38 in which it is determined whether the slip index Sx is greater than the slip threshold value S1. If the result is true, the method continues in step 39 with the determination of the speed of rotation of the wheel WOref. If the result is false, the method continues in step 40. In step 40, it is determined whether the slip index Sx is less than the restart threshold value S3 and less than the slip threshold value. S1. If the result is true, the process continues in step 41 with the determination of the torque setpoint at the restart wheel TOrel. If the result is false, the process proceeds to step 42.

In step 42, the torque setpoint is determined at the wheel TOref. Whatever the situation of the vehicle, corresponding in terms of process to one of the steps 39, 41 or 42, the method continues by determining the torque setpoints TE1 of the first electrical machine, TE2 of the second electrical machine and TIcE of the heat engine. The control system and / or the control method make it possible to control a powertrain in situations involving a sliding of at least one wheel. By comparing the speed of the vehicle with the speed of rotation of the wheel considered, the control system is able to determine the behavior. Thus, the wheel can be recognized as sliding, as being in a recovery situation or even as being in a nominal situation. During a slip situation, the speed of rotation of a wheel is beyond the expected speed of rotation for the measured speed of the vehicle. In order to remedy this situation, the control system will control the speed of rotation of the wheel, ignoring the torque request of the driver. The rotational speed reference of said wheel is then placed at a level close to the expected speed of rotation in a nominal situation. A recovery situation follows a situation of slippage.

The wheel having undergone a controlled slip by the control system, sees its rotation speed gradually increased so as not to cause a new slip but while trying to meet the fastest torque request of the driver.

The control system and method, either directly applying the control of the sliding phase, or through the recovery phase, are able to control a slip situation and to make the control of the wheels of the vehicle to its driver.

Claims (15)

Motor vehicle powertrain control system (34) comprising at least two electric machines, at least one heat engine and an infinitely variable transmission mechanically connected to the electric machines and to the heat engine, characterized in that it comprises sensors (1); means for determining (17) the situation of the vehicle, capable of detecting wheel slip; and a wheel speed control means (11) adapted to determine torque setpoints of the power train (34) on receipt of a logic signal from the vehicle situation determining means (17). 2. Control system according to claim 1, comprising a switching means (30) and a control means (13) nominal, the switching means (30) being able to selectively direct the signals from the control means (11). from the wheel speed and the nominal control means (13) to the power unit (34) as a function of the logical situation signal issued by the vehicle situation determining means (17). 3. Control system according to one of claims 1 or 2, comprising a control means (12) stimulus, the switching means (30) being adapted to selectively direct the signals from the control means (11) of the wheel speed, control means (12) and control means (13) nominal to the powertrain (34) according to the logical situation signal issued by the determination means (17) of the situation of the vehicle. 4. Control system according to one of claims 1 to 3 comprising a means (4) for calculating the sliding control settings, able to determine a set speed of rotation of the wheel and a torque setpoint to the wheel of relaunching according to received signals from the sensors (1) and the determination means (17) of the vehicle situation. 5. Control system according to one of the preceding claims comprising means for calculating (5) nominal operating instructions, able to determine the power setpoint to be provided by the battery, the rotational speed setpoint of the engine and the torque setpoint at the wheel. 6. Control system according to claim 5, wherein the wheel speed control means (11) is adapted to determine the torque setpoints of the powertrain (34) according to the power setpoint to be provided by the battery, the rotation speed setpoint of the thermal engine determined by the calculating means (5) of the nominal operating instructions and as a function of the rotation speed of the wheel determined by the means of calculation (4) of the instructions slip control. 7. Control system according to one of claims 5 or 6, wherein the restart control means (12) is adapted to determine the torque setpoints of the powertrain (34) according to the power setpoint to be provided. by the battery, the nominal rotation speed of the engine determined by the calculation means (5) nominal operating instructions and as a function of the torque setpoint to the recovery wheel determined by the calculation means (4) sliding regulation instructions. 8. Control system according to one of claims 5 to 7, wherein the control means (13) nominal is adapted to determine the torque setpoints of the powertrain (34) according to the power setpoint to be provided by the battery, the reference speed of rotation of the engine and the torque setpoint to the wheel determined by the calculation means (5) nominal operating instructions. 9. A method for controlling a powertrain (34) of a motor vehicle comprising at least two electric machines, at least one heat engine and a transmission infinitely variablereliée mechanically to electric machines and the engine, characterized in that it comprises a detection step, during which at least one slip index of a wheel is determined; a comparison step, during which said slip index is compared with a stored slip threshold to determine if said wheel is in a slip situation; a determination step, during which torque setpoints of the electrical machines and the heat engine are determined according to the wheel situation. 10. Control method according to claim 9 further comprising, between the comparison and determination steps, a second comparison step during which: said slip index is compared with a memorized restart threshold in order to determine whether said wheel is in a nominal situation. 11. Control method according to one of claims 9 or 10 comprising between the comparison and determination steps, a third comparison step during which said sliding index is compared with a stored restart threshold to determine if said wheel is in a recovery situation. 12. The control method according to claim 10, wherein a power setpoint to be supplied by the battery, a setpoint of the rotational speed of the engine and a setpoint of torque to the wheel are determined if the vehicle is in a nominal situation. . 13. A control method according to claim 9, wherein a power setpoint to be provided by the battery, a setpoint of the rotational speed of the engine and a rotational speed of the wheel if the vehicle is in a slip situation. 14. A control method according to claim 11, wherein a power setpoint to be provided by the battery, a setpoint of the rotational speed of the heat engine and a torque setpoint to the recovery wheel are determined if the vehicle is in a vehicle. recovery situation. 15. Control method according to one of claims 12 to 14, wherein the torque setpoints of the electrical machines and the engine are determined as a function of the power setpoint to be supplied by the battery, the speed regulation setpoint. rotation of the engine and the torque setpoint at the recovery wheel.