METHOD FOR CONTROLLING A VEHICLE POWERTRAIN

Abstract

One aspect of the invention relates to a method 100 for controlling a powertrain of a vehicle, said method 100 comprising the steps, executed by means for controlling said vehicle, of: Detecting 101 an action by a driver which presages a future command to start a thermal engine of said vehicle, When said action by the driver is detected, the method 100 comprises the steps of: Activating 103 a first network of the vehicle; Activating 104 a gearbox of the vehicle, said activation of said gearbox comprising in particular a step of partially closing 1043 a main clutch of the vehicle arranged to couple a thermal engine with the gearbox. Figure 2

Description

Title of the invention: METHOD FOR CONTROLLING A POWERTRAIN OF A VEHICLE

[0001] One aspect of the invention relates to a method for controlling a powertrain of a vehicle. The technical field of the invention thus relates to that of powertrains, for example, of the rechargeable hybrid type, known as PHEV (for Plug-in Hybrid Electric Vehicle in English terminology).

[0002] A plug-in hybrid powertrain includes in particular: • a heat engine, • a direct-direct voltage converter arranged between a first network supplied by a traction battery having a voltage of, for example, between 350V and 800V, and a second network supplied by a service battery, for example of the 12V type, • a gearbox comprising an output shaft, said gearbox being equipped with: • an electric traction machine arranged to drive the output shaft in rotation, • a main clutch designed to couple the gearbox to the thermal engine, • a hydraulic system equipped in particular with a hydraulic circuit and an electric oil pump connected to the second network, • a service battery electrically supplying the electric oil pump, and • a traction battery electrically supplying the electric traction machine.

[0003] In this type of powertrain, in order to be able to start the powertrain, the various elements of the powertrain must be activated one by one successively to a command to start the powertrain by the driver by means of a simultaneous pressing of a start button and a brake pedal or by turning a key to a so-called start position. For example, the hydraulic circuit of the gearbox must be pressurized. This pressurization phase is one of the steps in activating the powertrain. The main clutch can be closed to couple the thermal engine to the gearbox only when the pressure in the hydraulic circuit is increased. Once closed, the electric traction machine is able to start the thermal engine. This pressurization lasts at least 1 second and is uncomfortable for the driver. In fact, when the driver simultaneously presses the start button and the brake pedal of the vehicle, the driver must wait at least 1 second for the hydraulic circuit to be pressurized before the thermal engine can be started.

[0004] In order to reduce waiting time, mechanisms for anticipating the start of the thermal engine are known. For example, document FR-A1-3132258 proposes, when the driver opens the driver's door of the vehicle, to activate the hydraulic system of the gearbox and to completely close the main clutch coupling the gearbox to the thermal engine with a view to a future start of the thermal engine.

[0005] If such an anticipation strategy makes it possible to reduce the starting time of the thermal engine, when the driver enters his vehicle and is late in starting it, the activation of the hydraulic system of the gearbox, and more particularly the maintenance in the closed state of the main clutch, generates unwanted noises that are uncomfortable for the driver and his occupants. Indeed, the closing of the main clutch is carried out by means of the hydraulic circuit equipped with at least one electric oil pump. Maintaining this main clutch in the closed state requires that this pump delivers a maximum flow rate generating unwanted noises audible to the occupants of the vehicle, thus creating a significant inconvenience that can make users believe that the vehicle has an anomaly.

[0006] The aim of the invention is to overcome the drawbacks of the prior art by proposing a method for controlling a powertrain of a vehicle making it possible to reduce the noise generated by the hydraulic system of the gearbox following an action by a driver which predicts a future command to start a thermal engine.

[0007] In this context, the invention thus relates, in its broadest sense, to a method for controlling a powertrain of a vehicle, the method comprising the steps, executed by control means of the vehicle, of: • Detecting an action by a driver which presages a future start command of a thermal engine of the vehicle, said action by the driver being prior to the start command, • When said driver action is detected, the method comprises a step of activating a first network of the vehicle comprising the steps of: • Closing contactors of a traction battery of the first network, then • Activate a DC-DC voltage converter of the vehicle electrically connecting the traction battery with a service battery of a second network of the vehicle, the service battery having a voltage lower than that of the first network, • The method comprising, in parallel with the step of activating a first network of the vehicle, a step of activating a gearbox of the vehicle comprising the steps of: • Pressurize, using an electric oil pump, a hydraulic system of the gearbox comprising an output shaft and a first electric traction machine arranged to rotate the output shaft, then • Partially close a main clutch of the vehicle designed to couple the thermal engine with the gearbox.

[0008] This aspect of the invention makes it possible to activate, in advance of a vehicle start command by the driver, a gearbox and a first network having, for example, a voltage of between 350V and 800V and the vehicle gearbox. The method according to this aspect of the invention thus makes it possible to reduce the vehicle start time.

[0009] It should also be noted that when the gearbox is activated, the main clutch coupling the thermal engine to the gearbox is partially closed (and not completely), thus significantly reducing the noise generated by the electric oil pump of the hydraulic system. The total closing of this main clutch is achieved only when the driver requests the starting of his vehicle by means of simultaneous pressing of a start button and a brake pedal or by turning a key to a so-called starting position.

[0010] In addition to the characteristics which have just been mentioned in the preceding paragraph, the method according to the invention may have one or more complementary characteristics among the following, considered individually or according to all technically possible combinations.

[0011] According to a non-limiting aspect of the invention, the partial closing of the main clutch is calibrated so that the main clutch is able to transmit a determined torque value of between 5Nm and 80Nm.

[0012] According to a non-limiting aspect of the invention, the determined torque value is a function of an oil temperature in the hydraulic system.

[0013] According to a non-limiting aspect of the invention, the step of activating a gearbox further comprises a step of energizing the first electric traction machine, said step of energizing the first electric traction machine being executed after the step of activating the first network.

[0014] According to a non-limiting aspect of the invention, the action of the driver is: • Unlocking a driver's door of the vehicle, • opening the driver's door, a driver's seat on a vehicle seat, or a driver's seat belt fastener.

[0015] According to a non-limiting aspect of the invention, the method comprises the steps of: When a driver action that predicts a future engine start command is detected, trigger a time counter, Detect a driver start command within a predetermined period counted by the time counter, Increase the pressure in the hydraulic system using the electric oil pump, Close the main clutch completely; then To start the vehicle using the combustion engine, start the combustion engine, or To start the vehicle using the first electric traction machine, prepare the combustion engine for a subsequent rapid restart of the combustion engine.

[0016] According to a non-limiting aspect of the invention, the total closure of the main clutch is calibrated so that the main clutch is able to transmit a determined torque value greater than 180 Nm.

[0017] According to a non-limiting aspect of the invention, when a start command is detected, the method comprises a step of energizing a second electric traction machine connected to a rear axle of the vehicle.

[0018] According to a non-limiting aspect of the invention, When an action by a driver that predicts a future command to start a thermal engine is detected, the method comprises a step of triggering a time counter, if no start command and no request to switch on the vehicle are detected at the end of a predetermined period counted by the time counter, the method comprises the steps of: deactivate the gearbox, and deactivate the first network.

[0019] According to a non-limiting aspect of the invention, • the step of deactivating the gearbox includes the steps of: • switch off the first electric traction machine, • in parallel with said step of switching off the first electric traction machine, open the main clutch, then • remove pressure from the hydraulic system, • the step of deactivating the first network includes the steps of: • once the step of switching off the first electric traction machine has been carried out, deactivate the direct-direct voltage converter, then • open the traction battery contactors.

[0020] Another aspect of the invention relates to a vehicle comprising control means arranged to implement the method for controlling a powertrain according to any one of the aforementioned aspects of the invention.

[0021] The invention and its various applications will be better understood by reading the following description and examining the accompanying figures.

[0022] [Fig-1] illustrates, schematically, a vehicle according to a non-limiting aspect of the invention.

[0023] [Fig.2] schematically represents a non-limiting mode of implementation of the method according to the invention.

[0024] [Fig. 1] illustrates a vehicle 1 arranged to implement the method according to the invention. The vehicle 1 comprises in particular a powertrain 2 provided with: • a heat engine 3, • a DC-DC voltage converter 4 arranged between a first network supplied by a traction battery 5 having a voltage of, for example, between 350V and 800V, and a second network supplied by a service battery 6 having a voltage of, for example, between 10V and 50V, • a gearbox 7 comprising an output shaft 8, the gearbox 7 being equipped, in this non-limiting example embodiment, with: • a dual-clutch gearbox 9, • a first electric traction machine 10, • a main clutch 11 arranged to couple the thermal engine 3 with 7 speed gearbox, • A hydraulic system 12 provided in particular with at least one electric oil pump 13 connected to the second network and a hydraulic circuit (not illustrated), • a second electric traction machine 14.

[0025] For the remainder of the description, the traction battery 5 and the DC-DC voltage converter 4 together form the high-voltage network.

[0026] The vehicle 1 further comprises control means 15 arranged to implement a method for controlling a powertrain 2 of a vehicle 1 according to one aspect of the invention.

[0027] In a non-limiting exemplary embodiment, the control means 15 may comprise: • a 16-bit engine multifunction calculator, also known as CMM, • a transmission control unit 17 (better known by the acronym TCU for Transmission Control Unit in English), • a motor control unit 18 (better known by the acronym MCU for Motor Control Unit in English), and • A battery control system 19 (better known by the acronym BMS for Battery Management System in English).

[0028] [Fig. 2] shows the steps of an embodiment of the method 100 according to the invention. The steps of the method 100 are executed by control means such as, for example, the control means 15 shown in [Fig. 1].

[0029] The method 100 comprises a first step of detecting 101 an action of a driver which predicts a future command to start the thermal engine 3 of the vehicle 1. In one embodiment, the action of the driver is an opening of the driver's door of the vehicle 1. The action of the driver is prior to the start command. This detection can be carried out by means of a driver's door opening sensor (not shown) and transmitted to the engine multifunction computer 16.

[0030] When a door opening is detected, the method 100 comprises a step of triggering 102 a time counter. In a non-limiting embodiment, the engine multifunction computer 16 triggers the time counter.

[0031] When a door opening is detected, the method 100 also comprises a step of activating 103 the first network of the vehicle 1.

[0032] This step of activating 103 the first network of the vehicle 1 comprises a step of closing 1031 the contactors (not illustrated) of the traction battery 5 of the first network. In a non-limiting embodiment, the engine multifunction computer 16 transmits a request to the battery control system 19. Then the battery control system 19 controls the closing of the contactors.

[0033] These contactors are circuit breaker type contactors: • When they are closed, the current flows from the traction battery 5 to the electrical components of the vehicle 1, in other words the current can flow in the first network of the vehicle 1; • When they are open, the traction battery 5 is electrically isolated and current cannot flow into the first network of the vehicle 1.

[0034] The step of activating 103 the first network of the vehicle 1 further comprises a step of activating 1032 the voltage converter 4 electrically connecting the traction battery 5 with the service battery 6 of the vehicle. This step of activating 1032 the voltage converter 4 is carried out after the step consisting of closing 1031 the contactors of the traction battery 5. In a non-limiting embodiment, the multi-computer engine functions 16 transmits an activation request to the voltage converter 4. Thus, the voltage converter 4 is ready to supply energy to the service battery 6 via the traction battery 5 in order to avoid, for example, a voltage drop on the second network.

[0035] When a door opening is detected, the method 100 also comprises a step of activating 104 the gearbox 7.

[0036] This step of activating 104 the gearbox 7 comprises a step of pressurizing 104i, by means of the electric oil pump 13, the hydraulic system 12 of the gearbox 7. In a non-limiting embodiment, the engine multifunction computer 16 transmits a request to activate the hydraulic system 12 to the transmission control unit 17. This transmission control unit 17 then controls the partial pressurization of the hydraulic system 12, in particular via the activation of the electric oil pump 13. It should be noted that, in this embodiment, the step of pressurizing 104i the hydraulic system 12 of the gearbox 7 is carried out as soon as the door opening is detected.

[0037] The step of activating 104 the gearbox 7 further comprises a step of energizing 1042 the first electric traction machine 10. This step of energizing 1042 the first electric traction machine 10 is carried out after the step of activating 103 the first network of the vehicle 1. In a non-limiting embodiment, the engine multifunction computer 16 transmits a request to activate the first electric traction machine 10 to the engine control unit 18.

[0038] In a non-limiting embodiment not illustrated, the step of energizing 1042 the first electric traction machine 10 is executed when a start command is detected. This start command can be detected when the driver performs a start command, for example by means of pressing a start button and simultaneously pressing a brake pedal or by turning a key to a so-called start position, within a predetermined period counted from the triggering of the counter.

[0039] When the hydraulic system 12 of the gearbox 7 is pressurized, the step of activating 104 the gearbox 7 comprises a step of partially closing 1043 the main clutch 11 arranged to couple the thermal engine 3 with the gearbox 7. In a non-limiting embodiment, the engine multifunction computer 16 transmits a request for partial closing of the main clutch 11 to the transmission control unit 17. This transmission control unit 17 then controls the partial closing of the main clutch 11.

[0040] According to a non-limiting embodiment, the partial closing of the main clutch 11 is calibrated so that the main clutch 11 is able to transmit a determined torque value of between 5Nm and 80Nm, and more par- particularly between 20Nm and 30Nm.

[0041] To achieve such a torque value, the electric oil pump 13 is lightly stressed so that little noise, or even no noise, is heard by the occupants of the vehicle.

[0042] Furthermore, according to a non-limiting embodiment, the determined torque value is a function of an oil temperature that the hydraulic system 12 comprises. To this end, the transmission control unit 17 may comprise a temperature estimator or a temperature sensor arranged to determine the temperature of the oil present in the hydraulic system 12.

[0043] For example, in a non-limiting manner, when the temperature of the oil in the hydraulic system 12 is of the order of 20°C, the determined torque value that the partially closed main clutch 11 is able to transmit may be of the order of 20Nm.

[0044] According to another non-limiting example, when the temperature of the oil of the hydraulic system 12 is of the order of -30°C, the determined torque value that the partially closed main clutch 11 is able to transmit may be of the order of 50Nm.

[0045] Then, when the driver performs a start command, for example by means of pressing a start button and simultaneously pressing a brake pedal, within a predetermined period counted from the triggering of the counter, the method 100 comprises a step of detecting 105 a start command from the driver. In a non-limiting embodiment, the engine multifunction computer 16 detects this start command.

[0046] Following this detection of a start command, the method 100 comprises the steps of increasing the pressure 106, by means of the electric oil pump 13, of the hydraulic system 12 of the gearbox 7.

[0047] In a non-limiting embodiment, the engine multifunction computer 16 transmits a request to increase the pressure of the hydraulic system 12 to the transmission control unit 17. This transmission control unit 17 then controls the increase in pressure, in particular via the electric oil pump 13.

[0048] The method 100 then comprises a step of completely closing 107 the main clutch 11.

[0049] In a non-limiting embodiment, the engine multifunction computer 16 transmits a request for total closure of the main clutch 11 to the transmission control unit 17. This transmission control unit 17 then controls the total closure of the main clutch 11.

[0050] According to a non-limiting embodiment, the total closure of the main clutch 11 is calibrated so that the main clutch 11 is able to transmit a determined torque value greater than 180 Nm, typically greater than 200 Nm.

[0051] Following this total closure of the main clutch 11, the method 100 comprises, for starting the vehicle 1 by means of the thermal engine 3, a step 108a of starting the thermal engine 3. To this end, when the driver presses for example the start button and the brake pedal of the vehicle 1, the multifunction engine computer 16 transmits a request to the engine control unit 18 to control the first electric traction machine 10 to start the thermal engine 3.

[0052] In the case of starting the vehicle using the first electric traction machine 10, the method comprises a step 108b of preparing the heat engine 3 for a rapid restart of the heat engine 3. In an exemplary embodiment, the multifunction engine computer 16 transmits a request to the engine control unit 18 to control the first electric traction machine 10 to prepare the heat engine 3 for a rapid start.

[0053] In a non-limiting manner, this choice of starting the vehicle by means of the thermal engine 3 or the first electric traction machine 10 can for example be made as a function of the outside temperature and / or the charge of the traction battery 5.

[0054] In the case of a vehicle equipped with a second electric traction machine 14, if a start command is carried out within the predetermined period counted from the triggering of the counter, the method 100 comprises a step of energizing 109 the second electric traction machine 14. In an exemplary embodiment, the engine multifunction computer 16 transmits a request to the engine control unit 18 to energize the second electric traction machine 14.

[0055] On the other hand, if no start request and no request to switch on the vehicle ignition are detected at the end of the predetermined period, the method 100 comprises a step of deactivating 110 the gearbox 7. This predetermined period may for example be between 30 and 90 seconds, typically 60 seconds.

[0056] In one embodiment, the vehicle is switched on when a user positions a vehicle ignition key in an ignition on position, called "ignition on" in English terminology. This ignition on position is usually located between an Off position in English and a contact position in English.

[0057] In another embodiment, the vehicle is turned on when a user presses only a start button without pressing the ignition pedal. vehicle brake.

[0058] In a non-limiting embodiment, the step of deactivating 110 the gearbox 7 comprises a step of switching off 110i the first electric traction machine 10. In a non-limiting embodiment, the engine multifunction computer 16 transmits a request to switch off the first electric traction machine 10 to the engine control unit 18.

[0059] The step of deactivating 110 the gearbox 7 further comprises a step of opening 1102 the main clutch 11. In a non-limiting embodiment, the engine multifunction computer 16 transmits a request to open the main clutch 11 to the transmission control unit 17. This transmission control unit 17 then controls the opening of the main clutch 11.

[0060] The step of deactivating 110 the gearbox 7 also comprises a step of removing 1103 the pressure from the hydraulic system 12. In a non-limiting embodiment, the engine multifunction computer 16 transmits a request to remove the pressure from the hydraulic system 12 to the transmission control unit 17. This transmission control unit 17 then controls the removal of the pressure from the hydraulic system 12, in particular via the activation of the electric oil pump 13.

[0061] Furthermore, if no start command and no request to switch on the vehicle are detected at the end of the predetermined period, the method 100 comprises a step of deactivating 111 the first network of the vehicle 1. This step 111 begins as soon as the step of switching off 110i the first electric traction machine 10 is finished.

[0062] In a non-limiting embodiment, the step of deactivating 111 the first network comprises a step of deactivating 1111 the voltage converter 4. In a non-limiting embodiment, the engine multifunction computer 16 transmits a deactivation request to the voltage converter 4.

[0063] The step of deactivating 111 the first network finally comprises a step of opening 1112 the contactors of the traction battery 5. In a non-limiting embodiment, the engine multifunction computer 16 transmits a request to the battery control system 19 to open the contactors of the traction battery 5. Then, the battery control system 19 controls the opening of the contactors. Thus, the traction battery 5 is electrically isolated.

[0064] It should be noted that a person skilled in the art is able to provide different variations to the aforementioned aspects of the invention, for example by modifying the type of action by the driver which predicts a future command to start the vehicle's thermal engine.

Claims

Claims

1. Method (100) for controlling a powertrain (2) of a vehicle (1), said method (100) comprising the steps, executed by control means (15) of said vehicle (1), of: - Detect (101) an action of a driver which predicts a future start command of a thermal engine (3) of said vehicle (1), said action of the driver being prior to said start command, - When said driver action is detected, activating (103) a first network of said vehicle (1) comprising the steps of: • Closing (1030) contactors of a traction battery (5) of said first network, then • Activate (1032) a DC-DC voltage converter (4) of said vehicle (1) electrically connecting said traction battery (5) with a service battery (6) of a second network of said vehicle (1), said second network having a voltage lower than that of said first network, - In parallel with the step of activating (103) a first network of said vehicle (1), said method (100) comprises a step of activating (104) a gearbox (7) of said vehicle (1) comprising a step of: • Pressurizing (1040), by means of an electric oil pump (13), a hydraulic system (12) of said gearbox (7) comprising an output shaft (8) and a first electric traction machine (10) arranged to drive said output shaft (8) in rotation, • Said method being characterized in that said step of activating (104) a gearbox (7) further comprises a step of partially closing (1043) a main clutch (11) of said vehicle (1) arranged to couple the thermal engine (3) with the gearbox (7).

2. Method (100) according to the preceding claim, characterized in that the partial closure of the main clutch (11) is calibrated so that the main clutch (11) is able to transmit a determined torque value between 5Nm and 80Nm.

3. Method (100) according to the preceding claim, characterized in that the determined torque value is a function of an oil temperature included in the hydraulic system (12).

4. Method (100) according to any one of the preceding claims, characterized in that the step of activating (104) a gearbox (7) further comprises a step of energizing (1042) the first electric traction machine (10), said step of energizing (1042) said first electric traction machine (10) being executed after the step of activating (103) the first network.

5. Method (100) according to any one of the preceding claims, characterized in that the action of the driver is: - Unlocking a driver's door of the vehicle (1), - opening said driver's door, - seating of the driver on a seat of said vehicle (1), or - fastening a seat belt of said driver.

6. Method (100) according to any one of the preceding claims, characterized in that it comprises the steps of: - When an action by a driver that predicts a future start command of the thermal engine (3) is detected, triggering (102) a time counter, - detecting (105) a start command from the driver within a predetermined period counted by said time counter, then - Increasing (106) the pressure, by means of the electric oil pump (13), of the hydraulic system (12) of the gearbox (7), - Completely closing (107) the main clutch (11), then • For a start of the vehicle (1) by means of the thermal engine (3), starting (108a) said thermal engine (3), or • For a start of the vehicle (1) by means of the first electric traction machine (10), preparing (108b) said thermal engine (3) for a re- subsequent rapid start of said heat engine (3).

7. Method (100) according to the preceding claim characterized in that when a start command is detected, the method (100) comprises a step of energizing (109) a second electric traction machine (14) connected to a rear axle of the vehicle (1).

8. Method (100) according to any one of claims 1 to 5 characterized in that it comprises the steps of: - When an action by a driver which predicts a future command to start a thermal engine (3) is detected, triggering (102) a time counter, - if no start command and no request to switch on the vehicle are detected at the end of a predetermined period counted by said time counter, the method (100) comprises the steps of: • Deactivating (110) the gearbox (7), and • Deactivating (111) the first network.

9. Method (100) according to the preceding claim characterized in that: - The step of deactivating (110) the gearbox (7) comprises the steps of: • Switching off (110x) the first electric traction machine (10), • In parallel with said step of switching off (110i) the first electric traction machine (10), opening (1102) the main clutch (11), then • Removing (1103) the pressure from the hydraulic system (12), - The step of deactivating (111) the first network comprises the steps of: • Once the step of switching off (1100) the first electric traction machine (10) has been executed, deactivating (1110) the DC-DC voltage converter (4), then • Opening (1112) the contactors of the traction battery (5),

10. Vehicle (1) characterized in that it comprises control means (15) arranged to implement the method (100) for controlling a powertrain (2) according to any one of the preceding claims.

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