FR2911566A1 - Hybrid powertrain controlling system for e.g. four-door sedan, has calculating unit determining setpoints for heat and electric engine units, starter-alternator and clutch, from battery charge state of battery, speed and torque request - Google Patents

Abstract

The system has a powertrain (2) including a heat engine unit (2a) and an electric engine unit (2e). A calculating unit (8) determines operating setpoints for the heat engine unit, electric engine unit, starter-alternator (2b) and clutch (2c) from a charge state of a battery (5), speed of a motor vehicle and total torque request from a driver during starting phases. An interface (6) between the driver and vehicle is connected to the calculating unit and transmits information to the calculating unit on the request of the driver. An independent claim is also included for a method for controlling a hybrid powertrain unit.

Description

A system and method for controlling a hybrid powertrain for a

four-wheel drive vehicle

  The invention relates to powertrain control systems of a four-wheel drive vehicle and management of a hybrid propulsion system. Rising oil prices have made reducing motor vehicle fuel consumption both necessary and economically viable. The techniques associated with reducing fuel consumption were first applied to vehicles likely to reach a wide audience, usually sedans or city cars. In view of the expected tightening of legislation for vehicles with high fuel consumption, particularly for so-called four-wheel drive vehicles, it has become advantageous to provide these vehicles with techniques for reducing fuel consumption and pollution, such as propulsion. hybrids. However, little research has been done to reconcile reduced fuel consumption and drivability management of a four-wheel drive vehicle. The patent application FR 2654682 describes a control system for driving a four-wheel drive vehicle by distributing the torque of the internal combustion engine on the two front and rear trains using a mechanical torque transmission system. However, it does not integrate the use of several sources of motive power, nor the use of different motor sources. The invention relates to a powertrain control system of a hybrid four-wheel drive vehicle that can optimize the operation of the powertrain in the transitional takeoff phases to minimize energy consumption while ensuring the approval of conduct. By takeoff of a hybrid vehicle is meant the phase between a first and a second state of the vehicle. In the first state, the vehicle is stopped, without transmission of torque to the wheel. In the second state, the vehicle is in motion with the transmission in a stable state, open or closed. In one embodiment, a hybrid powertrain control system is defined for a four-wheel drive motor vehicle, comprising a powertrain and a battery. The powertrain in turn comprises a heat engine member, an electric drive member, an alternator and a clutch. The control system also comprises a calculation means able to determine operating instructions for the thermal engine unit, the electric motor unit, the alternator and the clutch, from the state of charge of the battery, the speed of the vehicle and the driver's overall torque request. In other words, the control system receives the driver's total torque request as well as information about the state of charge of the battery, and the speed of the vehicle. These data are analyzed by the control system which emits on its outputs commands for the thermal engine member, the electric motor unit, the alternator and the clutch. These instructions take into account the driver's request and also the reduction of energy consumption and driving pleasure. Such a control system may comprise an interface between the driver and the vehicle connected to the calculation means and capable of sending to the calculation means information on the overall torque request of the driver. The calculating means comprises a means for determining the setpoints of the powertrain and a means for translating the commands into commands, the calculation means receiving on its inputs information on the speed of the vehicle, the overall torque request of the driver, and the state of charge of the battery, and emitting on its outputs control signals to the thermal engine member, the electric motor unit, alternator starter and the clutch.

  The setpoint determination means receives on its inputs information concerning the speed of the vehicle, the state of charge of the battery and the overall torque setpoint demanded by the driver coming from the interface between the driver and the vehicle. The means for determining the setpoints comprises a take-off phase detecting member, an optimal engine speed calculating member and a transmission torque determining member. The means for determining the setpoints emitting on its outputs a torque setpoint on the front axle, a torque setpoint on the rear axle, a torque setpoint of the alternator, and a speed setpoint of the engine to the translation means instructions on orders. The means for translating the commands into commands receives on its inputs the instructions from the means for determining the instructions. The means for translating the commands into commands comprises a torque rocker member, a filter member and a correction member. The means of translation of the commands commands emits on its outputs torque commands to the engine member, the electric motor unit, the alternator and the clutch. According to another aspect of the invention, there is defined a method of controlling a hybrid powertrain for a four-wheel drive motor vehicle, comprising a battery, a heat engine member, an electric motor unit, an alternator and a clutch. The control method determines the operating instructions for the heat engine member, the electric motor unit, the alternator starter and the clutch, from the state of charge of the battery, the speed of the vehicle and the driver's global torque request.

  A take-off phase is then detected, an optimum engine speed is calculated and a torque setpoint is determined on the front axle, a torque setpoint on the rear axle, a torque setpoint of the alternator starter, and an engine speed reference. engine, from the vehicle situation and the driver's overall torque request. The operating instructions of the powertrain are determined from the torque setpoints and taking into account driving pleasure. 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 shows the main constituent elements a control system as described in the invention; FIG. 2 shows the main elements constituting a means for determining the instructions; FIG. 3 shows the main elements constituting a means of translation of the instructions into commands. Figure 1 shows a vehicle 1 comprising a powertrain 2, a train 3 front wheels, a train 4 rear wheels, a battery 5 and an interface 6 between the driver and the vehicle. The powertrain 2 comprises a thermal engine member 2a, an alternator 2b both connected by a clutch 2c and a gearbox 2d to the train 3 front wheels. The powertrain 2 also comprises a second electric drive member driving the train 4 rear wheels and being connected to a battery 5. The powertrain 2 is controlled by the means 8 of calculation. The means 8 for calculating comprises a means 7a for determining the instructions and a means 7b for translating the instructions into commands. The means 7a for determining the setpoints is connected via its inputs to the interface 6 between the driver and the vehicle via the connection 9, to the battery 5 via the connection 10 and to the vehicle via the connection 11. The means 7a for determining the setpoints is connected by its outputs by means of translation 7b of the instructions in commands, the connection 12 carrying the torque setpoint signals on the front train Cons_av, the connection 13 carrying the torque setpoint signals on the rear train Cons_ar, the connection 14 carrying the torque reference signals of the alternator Starter Cons_ad, and the connection 15 bearing the speed reference signals of the thermal engine member Cons_Mth. The means 7b for translating the commands into commands receives on its inputs signals from the means 7a for determining the setpoints, the connection 12 carrying the torque setpoint signals on the forward gear Cons_av, the connection 13 carrying the torque command signals. on the rear train Cons_ar, the connection 14 carrying the torque reference signals of the alternator Starter Cons_ad, and the connection 15 bearing the speed reference signals of the thermal engine member Cons_Mth. The means 7b for converting the commands into commands is also connected by one of its inputs to the thermal engine member 2a through the connection 16 carrying the speed signals of the thermal engine member Cons_Mth. The means 7b for converting the commands into commands is connected via its outputs to the thermal engine unit 2a via the connection 17, to the second electric motor unit via the connection 18, to the alternator starter 2b via the connection 19 and to the clutch 2c not the connection 20. Figure 2 shows the main components of the means 7a for determining the instructions. The connection 9 carries the request for overall torque of the driver Req_C, the connection 10 carries the state of charge of the battery EBT and the connection 11 carries the speed of the vehicle Vveh. The connections 9, 10 and 11 are connected to the member 21 for calculating the optimum engine speed. One of the outputs of the organ 21 for calculating the optimum engine speed is connected to the connection 15. A connection 1b carrying the information of the vehicle speed Vveh and a connection 25 carrying the engine speed reference signals. Thermal Cons_Mth are connected to the body 22 for detecting a take-off phase. One of the outputs of the body 22 for detecting a take-off phase is connected by the connection 24 to the transmission torque determining member 23.

  The connection 9a carries the global torque request of the driver Req_C, the connection 10a carries the charge state of the battery EBT and the connection 1 carries the speed of the vehicle Vveh, and are connected to the input of the determination member 23 transmission couples. The transmission torque determining member 23 is connected via its outputs to the connections 12, 13 and 14. The optimum engine speed calculating member 21 determines an optimum engine speed setpoint for the heat engine member Cons_Mth as a function of the total torque request of the driver Req_C, the state of charge of the battery EBT and the speed of the vehicle Vveh. The determination is made in order to minimize fuel consumption. This information is transmitted by means 7b of translation of the instructions in commands and the body 22 for detecting a take-off phase.

  The body 22 for detecting a take-off phase compares the optimal engine speed setpoint for the heat engine member Cons_Mth with the speed of the primary shaft of the gearbox 2d deduced from the vehicle speed Vveh. This comparison makes it possible to determine whether the vehicle is in a take-off phase or not.

  If the body 22 for detecting a takeoff phase detects a take-off phase, it sends a signal to the member 23 for determining the transmission torques. The transmission torque determining member 23 determines torque setpoints for the inter-starter Cons_ad, for the front train Cons_av and the rear train Cons_ar so as to satisfy the overall torque request of the driver Req_C and to minimize the fuel consumption. and energy. The transmission torque determining member 23 transmits the setpoint Cons_av on the connection 12, the setpoint Cons_ar on the connection 13 and the setpoint Cons_ad on the connection 14. This determination of the transmission torques is activated by the reception of a signal from the body 22 for detecting a take-off phase. FIG. 3 describes the main organs of the means 7b for translation of the instructions into commands.

  The connection 12 carries the torque reference signals on the front train Cons_av, the connection 13 carries the torque setpoint signals on the rear train Cons_ar and the connection 14 carries the torque command signals of the alternator Starter Cons_ad. The connections 12, 13 and 14 are connected to the torque rocker member 26. The torque rocker member 26 distributes a portion of the torque between the front axle and the rear axle in order to optimize the application of the overall torque regulation of the driver at the wheel, taking into account the instantaneous limitations of the electric motor. 2nd, clutch 2c and alternator starter 2b. The torque rocker member 26 transmits the torque setpoint of the front axle after flip-flop Cav via the connection 27, the torque setpoint of the rear axle after flip-flop by the connection 28 and the torque setpoint of the alternator after the rocker Cad through the connection 29 to the filter member 30. The filtering member 30 makes it possible to limit jolts, oscillations or mechanical vibrations of the powertrain 2, in order to improve driveability. The filtering member 30 transmits via the connection 17 a control of the clutch Com_Emb, by the connection 18 a control of the electric drive member Com_ME and by the connection 19 a command of the alternator Starter Com_ad. The connection 15 at the input of the means 7b for converting the setpoints into commands carrying the optimal engine speed setpoint for the heat engine element Cons_Mth and the connection 16 coming from the heat engine element 2a bearing the measurement of the speed of the drive member thermal C_Mth are connected to a first adder 31. The output of the first adder 31 is connected to the corrector 32 by the connection 33. The output of the corrector 32 and the connection 19a bearing the information of the control of the alternator Starter Com ad are connected to the second adder 34.

  The output of the second adder 34 and the connection 17a bearing the information of the control of the clutch Com_Emb are connected to the third adder 36. The output of the adder 36 is connected to the connection 20.

  The first adder 31 realizes the difference between the optimum engine speed setpoint for the heat engine element Cons Mth and the measurement of the speed of the thermal engine element CMth. This difference in speed is transmitted to the corrector 32 which translates the speed difference in torque control to the heat engine member 2a. The adder 34 subtracts from this command the torque command for the alternator Starter Com_ad received via the connection 19a. The intermediate command from the adder 34 is sent to the adder 36 which adds to the intermediate command the torque command for the clutch Com_Emb received from the connection 17a in order to obtain the torque control of the motor unit thermal Com_Mth. This control is emitted by the connection 20. The invention makes it possible to control a hybrid powertrain in a four-wheel drive vehicle in order to minimize the energy consumption during the take-off phase. The energy reduction takes into account both the electrical energy contained in the battery and the energy in the form of fuel, and allows for global savings regardless of the type of energy taken into account.

  As such, the invention is applicable to other combinations of driving members. In addition, the invention takes into account the pleasure of driving to limit jolts powertrain 2 which can degrade the feeling of the driver. In conclusion, the means 7a for determining the setpoints determines a speed reference of the thermal engine member and detects a take-off phase according to the comparison of the speed of the thermal engine member Cons_Mth and detects a takeoff phase with the speed of the Vveh vehicle. When a takeoff phase is detected, the torque setpoints for the alternator Starter Cons_ad, for the front train Cons_av and the rear train Cons_ar are determined. The torque setpoints for the Cons_ad alternator, for the Cons_av front axle and the Cons_ar rear axle are then split into a pair between the front and rear axles in order to optimize consumption. One last optimization is to smooth out torque variations to improve driveability. A control of the Com_Emb clutch, a command of the electric motor unit Com_ME and a command of the alternator Starter Com_ad are then issued. At the same time, the optimum engine speed setpoint for the heat engine unit Cons_Mth and the measurement of the speed of the thermal engine element C_Mth are compared, their difference translated into a control and modified so as to take account of the control of the alternator starter. Com_ad and Com_Emb clutch control. A Com_Mth command is then sent to the thermal engine unit. The invention is also complementary to a large number of systems intended to control the fuel consumption by the fact that it is particularly intended to limit the fuel consumption in the initial phase of setting the vehicle in motion, a phase rarely discussed. by the control systems. Finally, it is conceivable that the transmission torque determining member takes into account the speed gear ratio instructions in order to extend the optimization area of the operating point of the power unit.

Claims (8)

  A control system of a hybrid power train for a four-wheel drive motor vehicle, comprising a power train (2) comprising a heat engine member (2a), a battery (5), an electric drive member (2e), an alternator starter (2b) and a clutch (2c), characterized in that the control system comprises a means (8) for calculating able to determine operating instructions for the thermal engine member (2a), the drive member (2e), the alternator (2b) and the clutch (2c), from the state of charge of the battery (5), the speed of the vehicle and the overall torque request of the driver during the takeoff phases.   2. A control system according to claim 1 comprising an interface (6) between the driver and the vehicle connected to the means (8) of calculation and capable of sending to the means (8) calculation of information on the global torque request of the driver.   3. Control system according to claim 1 or 2 wherein the means (8) for calculating comprises means (7a) for determining the setpoints of the powertrain (2) and means (7b) for translating orders into commands, the calculation means (8) receiving on its inputs information on the speed of the vehicle, the overall torque request of the driver, and the state of charge of the battery (5), and emitting on its outputs control signals to the thermal engine member (2a), the electric motor unit (2e), alternator starter (2b) and the clutch (2c).   4. Control system according to claim 3 wherein the means (7a) for determining the setpoints receives on its inputs information on the speed of the vehicle, the state of charge of the battery (5) and the global torque setpoint requested by the driver coming from the interface (6) between the driver and the vehicle, the means (7a) for determining the setpoints comprises a member (22) for detecting a take-off phase, a member (21) for calculating the speed optimum motor and a member (23) for determining the transmission torques, the means (7a) for determining the setpoints emitting at its outputs a torque setpoint on the front axle, a torque setpoint on the rear axle, a torque setpoint of the alternator (2b), and a speed reference of the thermal engine member (2a) to the means (7b) for translating the instructions into commands.   5. Control system according to claim 4 wherein the means (7b) for translating the commands into commands receives on its inputs the instructions from the means (7a) for determining the instructions and comprises a member (26) of torque rocker, a filtering member (30) and a correction member, the means (7b) for translating the commands into commands being able to transmit on its outputs torque commands to the thermal engine member (2a), the driving member electrical (2nd), the alternator (2b) and the clutch (2c).   A method of controlling a hybrid power train for a four-wheel drive motor vehicle, comprising a heat engine member (2a), a battery (5), an electric motor member (2e), an alternator starter (2b) and a clutch (2c), characterized in that the operating instructions for the heat engine element (2a), the electric motor unit (2e), the starter motor (2b) and the clutch (2c) are determined. , from the state of charge of the battery, the speed of the vehicle and the request for overall torque of the driver.   7. A control method according to claim 6 wherein detects a take-off phase, calculates an optimum engine speed and determines a torque setpoint on the front axle, a torque setpoint on the rear axle, a torque setpoint of the alternator starter (2b), and a speed reference of the thermal engine member (2a), from the vehicle situation and the overall torque request of the driver.   8. Control method according to claim 7 wherein the operating instructions of the powertrain group (2) are determined from the torque setpoints and taking into account the driving pleasure.