Method for activating a hybrid powertrain with partial parallelisation of tasks

Abstract

The invention relates to a method for activating a hybrid powertrain of a motor vehicle, the method comprising, following a detection of a request from a driver to activate the hybrid powertrain: - a step of closing electrical contactors of the traction battery (19), - a step of activating the DC / DC converter (26), - a step of diagnosing the low-voltage electrical network (27), and - a step of activating the rotary electric machine (15), - the step of activating the alternator-starter (20) being carried out as soon as the electrical contactors of the traction battery (19) are closed, and - in the case where a need to perform the step of diagnosing the low-voltage electrical network (27) is detected using the alternator-starter (20), the step of starting the thermal engine (11) is delayed until the end of the step of diagnosing the low-voltage electrical network (27) is detected.

Description

DESCRIPTION TITLE: METHOD FOR ACTIVATING A HYBRID POWERTRAIN WITH PARTIAL PARALLELIZATION OF TASK

[0001] The present invention claims priority from French application No. 2212278 filed on 24.11.2022, the content of which (text, drawings and claims) is incorporated herein by reference.

[0002] The present invention relates to a method for activating a hybrid powertrain with partial parallelization of tasks. The invention finds a particularly advantageous application with two- or four-wheel drive hybrid automotive vehicles.

[0003] In a manner known per se, a hybrid powertrain of a motor vehicle may comprise an electric transmission device comprising a dual-clutch gearbox and a rotating electrical machine, an alternator-starter, a heat engine, and an electrical system composed in particular of a direct-direct converter (or DC / DC converter) and a traction battery.

[0004] The inventive entity has developed a method for activating a powertrain illustrated by Figure 1 comprising a first step 100 of waking up the computers following an opening of the driver's door. After waking up the computers, a mechanical part of the gearbox is activated in a step 101 by pressurizing a hydraulic circuit making it possible to control the opening and closing of the various clutches of the gearbox.

[0005] The next step 102 of this sequence is the detection of the driver's request for activation of the powertrain. During a step 103, the closing of a clutch coupling the thermal engine and the electric machine of the electric transmission device is carried out simultaneously with the activation of the electrical system.

[0006] The activation of the electrical system is composed of 3 main steps: the first step 104 being the closing of the traction battery contactors, the second step 105 being the activation of the DC / DC converter and the third step 106 being the carrying out of a diagnosis of a low voltage electrical network of the motor vehicle.

[0007] Once the electrical system is activated, it is the turn of the alternator-starter and the electrical machine of the electrical transmission device to be activated respectively during steps 107 and 108. In parallel, the electrical system will continue its activation by activating the DC / DC converter (see step 105) and by carrying out the diagnosis of the low voltage electrical network (see step 106).

[0008] As soon as the rotating electrical machine and the alternator-starter are activated, a final step 109 consists of starting the thermal engine using both the alternator-starter and the electrical machine of the electrical transmission device. The starting of the thermal engine is carried out in two steps: a first step 109a consists of tensioning the belt of the alternator-starter in order to limit its degradation over time and a second step 109b consists of starting the thermal engine by means of the alternator-starter and the rotating electrical machine of the electrical transmission device.

[0009] The problem with this sequence is that it is not applicable in all life cases, especially when the diagnosis of the low voltage electrical network must be carried out with the contribution of the alternator-starter.

[0010] In fact, there are two ways to perform low-voltage electrical network diagnostics. In the nominal case, the first method is based solely on the use of the DC / DC converter that generates predetermined current signals. Based on a voltage response of the low-voltage electrical network, the operating diagnosis can be established.

[0011] In certain life cases, particularly when the traction battery is "full" (very heavily charged) or in the event of overheating, it is not possible for the DC / DC converter to generate these current calls because the traction battery cannot accept the excess electrical current. In this case, the diagnosis of the low voltage electrical network is carried out in a second way by the DC / DC converter with contribution from the alternator-starter which is controlled in a specific mode, called "battery diagnosis" mode. This allows the traction battery to be discharged so that it can accept the current call that the DC / DC converter makes on the low voltage electrical network.

[0012] In the case where the diagnosis of the low voltage electrical network must be carried out with contribution from the alternator-starter, the sequence described above cannot be implemented because it requires parallelization of the diagnosis of the low voltage electrical network with the starting of the thermal engine. The engine is also started with the contribution of the alternator-starter which is then controlled in "torque" mode.

[0013] We then find ourselves in a life situation in which the performance of a diagnosis of the low voltage electrical network which requires the "battery diagnosis" mode is carried out at the same time as a start of the thermal engine which requires the "torque" mode of the alternator-starter. The alternator-starter being incapable of responding to two modes in parallel, the aforementioned sequence of tasks cannot therefore be carried out in this particular life situation.

[0014] The invention aims to effectively overcome this drawback by proposing a method for activating a hybrid powertrain of a motor vehicle comprising an electric transmission device provided with a dual-clutch gearbox and a rotating electrical machine, an alternator-starter, a heat engine, and an electrical system composed in particular of a traction battery and a DC / DC converter electrically connected between a low-voltage electrical network and a high-voltage electrical network, said method comprising, following detection of a request to activate said hybrid powertrain from a driver, - a step of closing the electrical contactors of the traction battery, - a step of activating the DC / DC converter, - a diagnostic step of the low voltage electrical network, and - a step of activating the alternator-starter, - a step of activating the rotating electrical machine of the electrical transmission device, and - a thermal engine start-up step, - the step of activating the alternator-starter being carried out as soon as the electrical contactors of the traction battery are closed, and - in the event that a need is detected to carry out the low voltage electrical network diagnostic step using the alternator-starter, the thermal engine starting step is delayed until the end of the low voltage electrical network diagnostic step is detected.

[0015] The invention thus makes it possible in certain life cases (traction battery too charged, high temperature, etc.) to sequence the use of the alternator-starter and to synchronize its use for carrying out the diagnosis of the low voltage electrical network and then for starting the thermal engine, thus avoiding any fault in the alternator-starter and failure of the activation of the powertrain.

[0016] According to one implementation of the invention, the alternator-starter switches to a battery diagnostic mode to participate in carrying out the diagnosis of the low voltage electrical network, and at the end of the diagnosis of the low voltage electrical network, the alternator-starter switches to a torque mode to participate in starting the thermal engine.

[0017] According to one implementation of the invention, a step of closing a clutch coupling the heat engine and the rotating electrical machine is carried out at least partially at the same time as an activation of the electrical system.

[0018] According to an implementation of the invention, as soon as the electrical contactors of the traction battery are closed, the step of activating the alternator-starter and the step of activating the rotating electrical machine of the device transmission are carried out temporally at least partially simultaneously with each other.

[0019] According to one implementation of the invention, the step of activating the DC / DC converter is carried out temporally at least partially simultaneously with the step of activating the alternator-starter and the step of activating the rotating electrical machine of the electrical transmission device.

[0020] According to one implementation of the invention, the step of starting the heat engine comprises a step of tensioning a belt of the alternator-starter and a step of starting the heat engine by means of the alternator-starter and the rotating electrical machine of the electrical transmission device.

[0021] According to one implementation of the invention, said method further comprises a step of activating a second rotating electrical machine installed on a rear wheel set of the motor vehicle.

[0022] According to one implementation of the invention, the step of activating the second rotating electrical machine is carried out at the same time as the activation of the alternator-starter and the rotating electrical machine.

[0023] According to one implementation of the invention, prior to detecting a request to activate said hybrid powertrain from a driver, said method comprises a step of waking up computers.

[0024] According to one implementation of the invention, the step of waking up the computers occurs after opening a door of the motor vehicle.

[0025] The invention will be better understood by reading the following description and examining the accompanying figures. These figures are given only for illustrative purposes but in no way limit the invention.

[0026] [Fig. 1], already described, is a time diagram of the different stages of a method of activating a hybrid powertrain according to the state of the art;

[0027] [Fig. 2] is a schematic representation of a powertrain implementing a method of activating a hybrid powertrain according to the invention;

[0028] [Fig. 3] is a time diagram of the different steps of a method of activating a hybrid powertrain according to the invention.

[0029] [Fig. 4] is a schematic representation illustrating exchanges of information between different elements of a hybrid powertrain during the implementation of the method according to the invention.

[0030] Figure 2 shows a hybrid powertrain 10 of a motor vehicle comprising a heat engine 11 and an electric transmission device 12 mounted on a wheel set 13, in particular a front wheel set.

[0031] The electric transmission device 12 comprises a rotating electric machine 15 and a dual-clutch gearbox 16 comprising two clutches K1, K2 for changing gear ratios. The rotating electric machine 15 is arranged at the input of the dual-clutch gearbox 16. The gearbox 16 comprises an input shaft 16.1 and an output shaft 16.2. The output shaft 16.2 of the gearbox 16 is connected to the wheels via a differential and a lowering axle (not shown).

[0032] Furthermore, a clutch KO for connecting and disconnecting the heat engine 11 is capable of selectively connecting the heat engine 11 to the input shaft 16.1 of the gearbox 16 when said clutch KO is in the closed state and of isolating the heat engine 11 from the input shaft 16.1 of the gearbox 16 when said clutch KO is in the open state. For this purpose, the clutch KO is arranged between the heat engine 11 and the rotating electrical machine 15. The insulation of the heat engine 11 from the input shaft 16.1 of the gearbox 16 and therefore in relation to the wheels is required in particular when the vehicle is operating in a pure electric driving mode. The KO clutch is associated with a flywheel 17.

[0033] The rotating electrical machine 15 is mounted between the clutch KO and the gear change clutches K1, K2 of the gearbox 16. The rotating electrical machine 15 can be connected to the input shaft 16.1 of the gearbox 16 via a belt or chain reduction unit 18.

[0034] The rotating electrical machine 15 is capable of transforming electrical energy from a traction battery 19 into mechanical energy to provide traction for the vehicle. The rotating electrical machine 15 is also capable of operating in a generator mode in which the rotating electrical machine 15 transforms mechanical energy into electrical energy to recharge the traction battery 19, in particular during a regenerative braking phase.

[0035] The heat engine 11 is associated with an alternator-starter 20. The alternator-starter 20 can be coupled with the heat engine 11 on the accessories front by means of a motion transmission device 22 with pulley and belt. An air conditioning compressor 23 can also be mounted on the accessories front.

[0036] The rotating electrical machine 15 and the alternator-starter 20 are electrically connected to the traction battery 19 on a high-voltage electrical network 25. The high-voltage electrical network 25 has an operating voltage of 48 volts, or even a voltage several hundred volts higher. The traction battery 19 is associated with electrical contactors making it possible to selectively electrically connect or electrically isolate the traction battery 19 from the high-voltage electrical network 25 and the electrical loads connected thereto.

[0037] A DC / DC converter 26 (or DC / DC converter) makes it possible to transform the voltage of the high-voltage electrical network 25 into a voltage compatible with a low voltage electrical network 27. This low voltage electrical network 27 comprises a low voltage battery 28. The low voltage electrical network 27 has an operating voltage of 12 Volts. On-board equipment 30 such as a lighting system, a human-machine interface such as a touch pad, for example, window or seat actuators, or any other low voltage equipment on board the vehicle are electrically connected to the low voltage electrical network 27. The DC / DC converter 26 and the traction battery 19 are part of an electrical system referenced 32. An oil pump 31 of the gearbox 16 is also electrically connected to the low voltage electrical network 27.

[0038] A supervisor 33 of a powertrain activation exchanges data with the electric transmission device 12, the alternator-starter 20, and a supervisor 34 of the electrical system 32. The supervisor 36 of the electrical system 32 exchanges data with the battery 19 and the DC / DC converter 26.

[0039] The method of activating the hybrid powertrain 10 is described below, with reference to FIGS. 3 and 4.

[0040] This method comprises a first step 100 of waking up the computers of the traction chain following an opening of the driver's door. The method then comprises a step 101 of activating a mechanical part of the gearbox 16 consisting of pressurizing a hydraulic circuit making it possible to control the opening and closing of the different clutches KO, K1, and K2 of the gearbox 16. This activation is requested by the supervisor 33 which sends an activation request R1 to the electric transmission device 12. The electric transmission device 12 transmits an activation state E1 to the supervisor 33.

[0041] The next step 102 of this sequence is the detection of a request for activation of the powertrain 10 by the driver. At the time of detection of this request for activation of the powertrain, the closing of the clutch KO coupling the heat engine 11 and the rotating electrical machine 15 of the electric transmission device 12 is carried out at during a step 103 at least partially at the same time as an activation of the electrical system 32.

[0042] The activation of the electrical system 32 is composed of 3 main steps: the first step 104 being the closing of the contactors of the traction battery 19, the second step 105 being the activation of the DC / DC converter 26 and the third step 106 being the carrying out of a diagnosis of the low voltage electrical network 27 of the motor vehicle. In this case, step 104 and at least part of step 105 are carried out at the same time as step 103 of closing the KO clutch. The activation of the electrical system 32 is supervised by the supervisor 34.

[0043] The supervisor 33 requests the activation of the electrical system 32 by sending a request R2. During or before the activation of the electrical system 32, the supervisor 34 detects a need to perform the diagnosis of the low-voltage electrical network 27 using the alternator-starter 20. This contribution request is then transmitted, via the request R3, to the supervisor 33. The supervisor 34 also transmits a status E2 of activation of the electrical system 32.

[0044] The contactors of the traction battery 19 are closed during a step 104. For this purpose, the supervisor 34 sends a request R6 to close the contactors and receives a status E5 of the contactors from the traction battery 16.

[0045] As soon as the contactors of the traction battery 19 are closed (end of step 104), the supervisor 34 of the electrical system 32 informs the supervisor 33 which then requests the activation of the alternator-starter 20 during a step 107. The supervisor 34 of the electrical system indicates its activation status to the supervisor 33 via the status information E2. The supervisor 33 sends an activation request R4 to the alternator-starter 20. The alternator-starter 20 transmits its activation status E4 to the supervisor 33.

[0046] Once the alternator-starter 20 is activated, the supervisor 33 requests during a step 107' the selection of the battery diagnostic mode of the alternator-starter 20 via a request R5 so that the supervisor 34 completes the activation of the electrical system 32 by carrying out during a step 106 the diagnosis of the low voltage electrical network 27 after the DC / DC converter 26 has been activated. To this end, the supervisor 34 sends a request R8 to the DC / DC converter 26, which informs the supervisor 34 of its state via the state information E7.

[0047] The activation of the rotating electrical machine 15 is requested, during a step 108, by the supervisor 33 as soon as the supervisor 34 of the electrical system 32 indicates, via the status information E2, that the contactors of the traction battery 19 are closed. For this purpose, the supervisor 33 sends an activation request R7 to the electrical transmission device 12. The electrical transmission device 12 communicates to the supervisor 33 the activation status of the rotating electrical machine 15 via the status information E6. Steps 107 and 108 are carried out temporally at least partially, preferably completely, simultaneously with each other.

[0048] In this case, step 105 of activating the DC / DC converter 26 is carried out temporally at least partially simultaneously with steps 107 and 108.

[0049] Step 106 of diagnosing the low voltage electrical network 27 is carried out after steps 107 and 108.

[0050] The supervisor 33 delays the start of the thermal engine 11 until the end of the diagnostic step 106 of the low voltage electrical network 27 is detected. This detection is carried out by the supervisor 34 of the electrical system 32 which informs the supervisor 33 via the status information E2.

[0051] The supervisor 33 controls the starting of the thermal engine 11 by requesting the alternator-starter 20 and the rotating electrical machine 15 to switch to a torque mode respectively via the transmission of requests R5 and R9. The alternator-starter 20 indicates its control mode to the supervisors 33 and 34 via the “Malt” information.

[0052] Step 109 consists of starting the thermal engine 11 in two steps: a first step 109a consists of tensioning the belt of the alternator-starter 20 in order to limit its degradation over time and a second step 109b consists of starting the thermal engine 11 by means of the alternator-starter 20 and the rotating electrical machine 15.

[0053] A variant of this sequence makes it possible to activate a rotating electrical machine (not shown) installed on the rear wheel set of the vehicle. The activation of this rotating electrical machine is then carried out during a step 110. Preferably, step 110 is carried out at the same time as the activation of the alternator-starter 20 and the rotating electrical machine 15 (steps 107 and 108). Step 110 begins at the end of the step of closing the electrical contactors of the traction battery 19.

Claims

CLAIMS 1. Method for activating a hybrid powertrain (10) of a motor vehicle comprising an electric transmission device (12) provided with a dual-clutch gearbox (16) and a rotating electrical machine (15), an alternator-starter (20), a heat engine (11), and an electrical system (32) composed in particular of a traction battery (19) and a DC / DC converter (26) electrically connected between a low-voltage electrical network (27) and a high-voltage electrical network (25), said method comprising, following detection of a request to activate said hybrid powertrain (10) from a driver, - a step (104) of closing electrical contactors of the traction battery (19), - a step (105) of activating the DC / DC converter (26), - a step (106) of diagnosing the low voltage electrical network (27), and - a step (107) of activating the alternator-starter (20), - a step (108) of activating the rotating electrical machine (15) of the electrical transmission device (12), and - a step (109) of starting the heat engine (11), characterized in that - the step (107) of activating the alternator-starter (20) is carried out as soon as the electrical contactors of the traction battery (19) are closed, and - in the case where a need is detected to carry out the step (106) of diagnosing the low voltage electrical network (27) using the alternator-starter, the step (109) of starting the thermal engine (11) is delayed until the end of the step (106) of diagnosing the low voltage electrical network (27) is detected.

2. Method according to claim 1, characterized in that the alternator-starter switches to a battery diagnostic mode to participate in carrying out the diagnosis of the low voltage electrical network (27), and at the end of the diagnosis of the low voltage electrical network (27), the alternator-starter (20) switches to a torque mode to participate in starting the thermal engine (11).

3. Method according to claim 1 or 2, characterized in that a step (103) of closing a clutch (KO) coupling the heat engine (11) and the rotating electrical machine (15) is carried out at least partially at the same time as an activation of the electrical system (32).

4. Method according to any one of claims 1 to 3, characterized in that as soon as the electrical contactors of the traction battery (19) are closed, the step (107) of activating the alternator-starter (20) and the step (108) of activating the rotating electrical machine (15) of the transmission device are carried out temporally at least partially simultaneously with each other.

5. Method according to any one of claims 1 to 4, characterized in that the step (105) of activating the DC / DC converter (26) is carried out temporally at least partially simultaneously with the step (107) of activating the alternator-starter (20) and the step (108) of activating the rotating electrical machine (15) of the electrical transmission device (12).

6. Method according to any one of claims 1 to 5, characterized in that the step (109) of starting the heat engine (11) comprises a step (109a) of tensioning a belt of the alternator-starter (20) and a step (109b) of starting the heat engine (11) by means of the alternator-starter (20) and the rotating electrical machine (15) of the electrical transmission device (12).

7. Method according to any one of claims 1 to 6, characterized in that it further comprises a step (110) of activating a second rotating electrical machine installed on a rear wheel set of the motor vehicle.

8. Method according to claim 7, characterized in that the step (110) of activating the second rotating electrical machine is carried out at the same time as the activation of the alternator-starter (20) and the rotating electrical machine (15).

9. Method according to any one of claims 1 to 8, characterized in that prior to the detection of a request for activation of said hybrid powertrain (10) from a driver, said method comprises a step of waking up computers.

10. Method according to claim 9, characterized in that the step of waking up the computers occurs after opening a door of the motor vehicle.

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