HYBRID MOTOR VEHICLE INCLUDING AN EMERGENCY STARTING MEANS VIA THE ELECTRIC MACHINE, METHOD AND PROGRAM BASED ON SUCH A VEHICLE

Abstract

The invention relates to a motor vehicle comprising: - a gearbox (GV); - an electric machine (EM); - a traction battery; - a heat engine (HE) coupled to the electric machine (EM) by a reversible coupling (E2); - a main starting element (ME) for the heat engine (HE); - a backup starting means (D) for the heat engine (HE) in case of malfunction of said element (ME); - at least one controller (C) detecting a malfunction of said element and starting means (ME) and, if sufficient charge is present, disengaging the heat engine (HE) and initiating a starting of the vehicle by said electric machine (EM). The invention also relates to a method and a program based on such a vehicle. Figure 1

Description

Title of the invention: HYBRID MOTOR VEHICLE COMPRISING A STARTING MEANS FOR EMERGENCY MOBILE RESCUE, METHOD AND PROGRAM BASED ON SUCH A VEHICLE

[0001] The invention relates to the field of hybrid vehicle starting systems.

[0002] In this field, document EP3318747 describes a method for starting an internal combustion engine of a motor vehicle powertrain, comprising a step of detecting a starting failure performed by a first starting element of the internal combustion engine according to one of a set of predetermined starting failure criteria. During the last step of the method, the powertrain management means control the activation of the starter-alternator after a delay depending on the detected failure criterion. At the end of this delay, the activation of the starter-alternator drives an input shaft of the internal combustion engine via the belt, which causes the internal combustion engine to start.

[0003] This solution is not fully satisfactory in the event of a malfunction of the alternator-starter in a hybrid engine.

[0004] On a project for an MHEV (for "mild hybrid vehicle"), the applicant has developed a function that detects when the internal combustion engine fails to start, either through the main starting device or through a backup starting function in degraded mode. This solution is also implemented on a project for a second-generation PHEV (for "plug-in hybrid vehicle").

[0005] Unfortunately, if the internal combustion engine cannot start with the main starting device and with the emergency starting function, the powertrain supervisor refuses to start, an error message is displayed on the instrument panel to inform that starting is impossible, and a stop light is illuminated.

[0006] There appears to be a need to create a function on second generation PHEV vehicles, which allows the vehicle to be engaged in driving even if the main start and the emergency start function do not allow the internal combustion engine to start.

[0007] One objective of the present invention is to remedy the shortcomings of the prior art, and in particular to provide a starting solution for hybrid vehicles in the event of malfunction of the main starting device and the backup starting function.

[0008] To achieve this objective, the invention proposes a motor vehicle comprising: - an automatic or automated manual transmission; - an electric machine coupled to the gearbox; - a traction battery connected to said electric machine; - a heat engine coupled to the electric machine by a reversible coupling; - a main starting device connected to the internal combustion engine starting the internal combustion engine; - an emergency starting method connected to the internal combustion engine that starts the internal combustion engine; - at least one controller connected to the main starting device, the emergency starting device, the reversible coupling, the electric machine, and the traction battery, said controller detecting a malfunction of the starting device main and activating a start via the emergency starting method in case of malfunction of the main starting device, said controller also detecting a malfunction in the emergency starting system, In the event of a malfunction of both the main starting device and the emergency starting means, the controller verifies whether the traction battery's state of charge exceeds a certain threshold, and if so, disengages the internal combustion engine and initiates vehicle movement using the electric motor.

[0009] Advantageously, the invention provides a function for starting the hybrid vehicle by the electric machine alone in the event of detection of the impossibility of starting the internal combustion engine by the main starting system and the emergency starting function.

[0010] Preferably, said controller detects a malfunction of the main starting device if a starting command is not implemented by the internal combustion engine for a period less than a first threshold period, or if several starting commands are not implemented by the internal combustion engine.

[0011] This allows for normal operation in the event of a slight malfunction of the main starting device.

[0012] In particular, said controller includes a powertrain supervisor overseeing a thermal engine computer, and the implementation of the thermal engine start is carried out by the thermal engine computer.

[0013] Preferably, said controller detects a malfunction of the backup starting means if a starting command is not implemented by the internal combustion engine for a period less than a second threshold period, or if several start commands are not implemented by the internal combustion engine.

[0014] This allows for normal operation in the event of a slight malfunction of the emergency starting means.

[0015] Preferably, in the event of a malfunction of both the main starting element and the backup starting means, said controller deactivates the main starting element and the backup starting means.

[0016] This helps to limit the risks of starting / restarting failure when said component and said starting means are faulty.

[0017] Preferably, said controller deactivates the internal combustion engine to perform driving in pure electric mode. This is done in particular by disengaging the internal combustion engine during driving, by means of said reversible coupling.

[0018] This helps to limit the risks of running defects when the internal combustion engine is faulty.

[0019] Preferably, said controller limits the discharge power of the traction battery.

[0020] This allows for driving over a long distance when the component and the starting means are faulty.

[0021] Preferably, said threshold is between 15 and 25%, and is preferably 20%.

[0022] This allows sufficient energy to be available for starting by the electric machine and for the vehicle to run in electric mode.

[0023] The invention also relates to a method for controlling the starting of a motor vehicle according to the invention, characterized in that it comprises the following steps: - an emergency starting step in which a malfunction of the main starting element is detected and a start is activated by the emergency starting means in the event of a malfunction of the main starting element; - a starting stage by the electric machine in which a malfunction is detected in both the main starting device and the emergency starting means, in which case it is checked whether the state of charge of the traction battery is above a threshold, and if so, the internal combustion engine is disengaged, and a vehicle start-up is activated by said electric machine.

[0024] Preferably, in the electric machine start-up step, the main starting device and the backup starting means are deactivated.

[0025] Another object of the invention relates to a computer program comprising program code instructions for executing the steps of the startup control method according to the invention, when said program is running on a computer.

[0026] The invention will be further detailed by the description of non-limiting embodiments, and on the basis of the attached [Fig. 1] schematically illustrating a hybrid vehicle architecture suitable for the implementation of the invention.

[0027] The invention proposes a way to start the hybrid vehicle even when the powertrain supervisor detects an inability to start the internal combustion engine by the main starting system and the backup starting function.

[0028] The aim is to prevent users from being stranded on the side of the road because of such a problem.

[0029] The gain is to allow the driver to avoid immobilizing the vehicle on the side of the road in order to get to the nearest maintenance service, or to be able to immobilize the vehicle in a secure place to avoid any accident with another vehicle.

[0030] The invention is all the more important as the push-start mode is not possible because the clutch is naturally open on the applicant's hybrid vehicles.

[0031] The architecture of the hybrid powertrain of PHEV vehicles is illustrated in [Fig.1],

[0032] This architecture consists of a thermal engine MT; an automatic or piloted gearbox BV, connected to an electric machine ME via a clutch El, the electric machine ME being connected to the thermal engine MT via a main clutch E2 of the powertrain; an alternator-starter AD connected to the thermal engine MT via an accessory front panel (including an accessory belt); in addition, a conventional starter D can also be mounted on the thermal engine MT.

[0033] Within the scope of the invention, a controller C can be described, but in the preferred embodiment, it represents several computers / controllers operating together. Indeed, different computers are involved in this process:

[0034] The electric traction machine computer (called "MCU"); it manages the electric traction machine of the vehicle; it exchanges information with a powertrain supervisor (called "CMM").

[0035] The powertrain supervisor: it coordinates / pilots / controls / supervises the powertrain computers; it also directly controls and pilots the operation of the MT internal combustion engine.

[0036] The traction battery computer (or controller) (called "BMS"): it manages the vehicle's traction battery; it exchanges information with the CMM supervisor regarding traction battery information.

[0037] Regarding the implementation of starting a thermal MT engine on a conventional powertrain, the main starting device (starter D or alternator-starter AD) drives the crankshaft to rotate up to about 200 rpm; and as the resisting torque of the internal combustion engine MT fluctuates according to the crankshaft angle, on the first turn of the crankshaft, the engine speed sensor identifies the top dead center of the crankshaft and during the second turn of the crankshaft, the computer identifies the area where the engine can inject fuel and the area where the spark plug (for the case of gasoline engines) must be supplied to ignite the "air / fuel" mixture to achieve the starting of the internal combustion engine MT.

[0038] Regarding the main starting device of an internal combustion engine, this is the device that starts the internal combustion engine MT when a start request is made by the internal combustion engine control unit MT or by the powertrain supervisor. This main starting device can be: - either a conventional starter; - either a reinforced STTd starter (i.e., a starter with reinforced brushes); - either an STTa alternator-starter.

[0039] The state of charge of a battery represents the charge level of the battery. Its unit is the percentage. When the state of charge is at 100%, the battery is said to be fully charged and when it is at 0%, the battery is said to be completely discharged.

[0040] Next, a distinction is made between the actual state of charge and the useful state of charge. A 50kWh battery will contain 50kWh at 100% of its actual state of charge; and it will contain 0kWh at 0% of its actual state of charge.

[0041] The usable state of charge is the electrical energy available to the driver. Its maximum value when new is often 97% of the actual state of charge: for sustainability reasons, when a user recharges at a charging station, charging stops at 100% of the usable state of charge, i.e., 97% of the actual state of charge of the battery pack. Thus, the stored energy is closer to 48 kWh than 50 kWh on a new vehicle.

[0042] The minimum state of charge when new is around 1 to 2% of the actual state of charge (this depends on the power cells).

[0043] The invention relates to an "electric emergency start" function on hybrid vehicles, in particular of the second generation PHEV type.

[0044] This function performs the following operations: - firstly, identify whether the main starting device (alternator-starter AD or starter D) of the MT internal combustion engine is operational or not; - secondly, it identifies whether the backup starting device (starter D or alternator-starter AD) of the MT internal combustion engine is operational or not; - if it is impossible to start the MT internal combustion engine, the function stops any attempt to start the MT internal combustion engine and acknowledges that it is impossible to use the MT internal combustion engine for the remainder of the vehicle's journey; - it checks the state of charge level of the high-voltage traction battery; - if the state of charge level is above a threshold, the function engages the driving mode in pure electric mode by the front ME electric machine for front-wheel drive vehicles or by both front and rear electric machines for four-wheel drive vehicles; - preferably, the function forces a limitation on the discharge power of the traction battery to allow the user to travel a maximum of kilometers with the energy contained in the traction battery.

[0045] Optionally, the function requests the illumination of a service light or a stop light on the dashboard to warn the driver that there is a problem with the vehicle and that it is in a degraded driving mode.

[0046] Regarding now a first phase of identification of a failure of the main starting unit, the "electrical backup start" function measures the start time of the MT internal combustion engine each time the CMM engine controller engages a start function of the MT internal combustion engine.

[0047] If the thermal engine speed has not reached idle speed in less than a time criterion noted CD1, the "electric emergency start" function considers that the starting of the thermal engine MT by the main starting device has failed.

[0048] On the other hand, if the MT internal combustion engine speed has reached idle speed in less than the CD1 duration criterion, the "electrical emergency start" function considers that the starting of the MT internal combustion engine by the main starting device has been successful.

[0049] In the event of a successful start of the MT thermal engine by the main starting device, the "electrical backup start" function is put on standby until the next request by the CMM motor controller for a start of the MT thermal engine.

[0050] However, if an unsuccessful start or restart of the internal combustion engine is detected, the "electric emergency start" function requests the illumination of the service indicator light on the instrument panel to indicate the detection of a problem in the powertrain. Alternatively, a fault code is stored in the read-only memory of a controller called the BSI, to help the maintenance department identify that the CMM engine controller was unable to start or restart the engine. MT thermal by the use of the main starting device and that the emergency starting function had to be triggered.

[0051] In particular, the CD1 duration is a time criterion entered into the read-only memory of the CMM motor controller by the development teams during the development of the emergency start function. The order of magnitude of this time criterion can be in the range of 500 ms to 900 ms. This CD1 duration depends on the characteristics of the internal combustion engine (gasoline / diesel, 3-cylinder / 4-cylinder, engine displacement, etc.).

[0052] Alternatively, it is possible that the emergency start function only considers a start failure after two aborted attempts to start or restart the MT internal combustion engine with the main starting device.

[0053] Regarding a second phase of identifying a failure of the emergency starting device, the "electric emergency start" function also detects whether the emergency start function still fails to start the MT thermal engine, that is to say, the "electric emergency start" function also measures the start time of the MT thermal engine each time the CMM engine controller engages an emergency start function.

[0054] If the thermal engine speed has not reached idle speed in less than a time criterion noted CD2, the "electric emergency start" function considers that the starting of the thermal engine MT by the emergency start function has failed.

[0055] On the other hand, if the thermal engine speed has reached idle speed in less than the CD2 duration criterion, the "electric emergency start" function considers that the start of the thermal engine MT by the emergency start function has been successful.

[0056] In the event of a successful start of the MT thermal engine by the emergency start function, the "electric emergency start" function is put on standby until the next request by the motor controller for a start of the MT thermal engine.

[0057] Conversely, if an unsuccessful start or restart of the MT internal combustion engine is detected by the emergency start function, the "electric emergency start" function requests the illumination of the service indicator on the instrument panel to indicate the detection of a problem in the powertrain. Alternatively, a fault code is stored in the BSI controller's read-only memory to assist the maintenance department in identifying that the CMM engine controller was unable to start or restart the MT internal combustion engine using the main starting device and the emergency start function.

[0058] In particular, the CD2 duration is a time criterion entered into the read-only memory of the CMM motor controller by the development teams during the development of the emergency start function. The order of magnitude of this time criterion can be in the range of 600 milliseconds to 2 seconds. This CD2 duration is preferably longer than CD1 and depends on the characteristics of the MT internal combustion engine (gasoline / diesel, 3-cylinder / 4-cylinder, engine displacement, etc.).

[0059] Alternatively, it is possible that the "electric emergency start" function only considers a start failure after two aborted attempts to start or restart the MT internal combustion engine by the emergency start function.

[0060] In a third phase, if it is impossible to start the MT internal combustion engine, the "electric emergency start" function stops any attempt to start the MT internal combustion engine and acknowledges that it is impossible to use the MT internal combustion engine for the remainder of the vehicle's driving.

[0061] More specifically, in the event that the emergency start function has failed to start or restart the MT internal combustion engine, the "electric emergency start" function will acknowledge the impossibility of starting the MT internal combustion engine and will therefore inhibit the following functions: the emergency start function of the CMM controller, the stop-start function (or "Stop and Start" in English) of the CMM controller, and any attempt to start the MT internal combustion engine, i.e. that the MT internal combustion engine is then permanently stopped, without any attempt to restart, until the driver turns off the ignition with the key or the vehicle's ignition push button.

[0062] In a fourth phase, the new "electric emergency start" function consults the state of charge level of the traction battery.

[0063] The state of charge level of the traction battery is measured by the BMS battery controller. This controller communicates the state of charge level of the battery to the powertrain supervisor via a CAN network of said powertrain.

[0064] The supervisor continuously retrieves the state of charge level of the traction battery and can thus compare it to a State of Charge Threshold (here referred to as SSOC). Specifically, the state of charge information is updated every 500 ms + / - 300 ms.

[0065] If the state of charge communicated by the BMS battery controller is below the SSOC threshold, the "electric emergency start" function initiates a first reconfiguration detailed below.

[0066] On the contrary, if the state of charge communicated by the BMS battery controller is above the SSOC threshold, the "electric emergency start" function engages a second reconfiguration detailed below.

[0067] Since the SSOC threshold is a calibrable variable during the development of the function, in our case, its value is calibrated to 20% SOC.

[0068] In a fifth phase, the first reconfiguration is implemented. It depends on the current operating state of the hybrid powertrain and the state of charge value relative to the SSOC threshold: - if the vehicle is already being driven by the electric traction machine ME, the "electric emergency start" function reduces the electrical power consumption of the traction battery to a power noted Plmax, which limits the torque of the electric traction machine ME; - If the vehicle is not already being driven by the electric traction machine, the "electric emergency start" function keeps clutches E1 and E2 open, and prevents the powertrain from engaging; that is, the vehicle cannot be driven by any traction component (thermal and / or electric). This is particularly the case if the state of charge level is too low relative to the SSOC threshold.

[0069] In particular, Plmax is a value calibrated during the development of the "electrical emergency start" function and can be, for example, 8.5kW at most.

[0070] Optionally, an illumination on the dashboard can be made to indicate the degraded mode to the user as a stop light (“STOP”) or a SERVICE light to indicate to go to the nearest maintenance service.

[0071] In a sixth phase, the second reconfiguration is initiated: if the state of charge communicated by the battery controller BMS is above the SSOC threshold, the "electric emergency start" function initiates the following operation: - if the vehicle is not already driven by the electric traction machine ME, the "electric emergency start" function checks that the clutch E2 is open, then closes the clutch El and controls the machine computer MCU so that the electric machine ME drives the vehicle in "pure electric" mode; but the "electric emergency start" function reduces the consumption of the traction battery's electrical power to a power denoted P2max, which limits the torque of the electric traction machine ME; - if the vehicle is already being driven by the electric traction machine ME, the "electric emergency start" function leaves clutch E2 open and clutch El closed; thus, the state of the clutches remains as it was.

[0072] In particular, P2max is a value calibrated during the development of the "electrical emergency start" function and can be, for example, 8.5kW at most.

[0073] Optionally, a dashboard light can be used to indicate the degraded mode to the user as a stop light (“STOP”) or a SERVICE light to indicate to go to the nearest maintenance service.

[0074] Furthermore, the "electric emergency start" function also reduces the electrical power consumption of the traction battery to the P2max power, which limits the torque of the electric traction machine ME.

[0075] To restore the vehicle's behavior, there are two possibilities: - either the driver switched off the powertrain at the dashboard (via the ignition key or via the dashboard ignition push button) and when he switched the ignition back on, the fault did not recur, i.e. the starting of the MT internal combustion engine became operational again; - either the user needs to bring their vehicle to the maintenance service to analyze the problem, find and repair the fault.

[0076] In the case of the option to apply a fault code, if the maintenance service does not intervene on the vehicle and the start or restart of the MT internal combustion engine is restored, the fault code changes from the state "permanent fault" to "intermittent fault".

[0077] The invention further relates to a method and a startup control program implementing the elements described above. The program can be loaded into the memory of one or more controllers.

Claims

Demands

1. Motor vehicle comprising: - an automatic or automated manual transmission (MMT); - an electric motor (EM) coupled to the transmission (MMT); - a traction battery connected to said electric motor (EM); - a combustion engine (CE) coupled to the electric motor (EM) by a reversible coupling (E2); - a main starting device (MD) connected to the combustion engine (CE) starting the combustion engine (CE); - an emergency starting device (ED) connected to the combustion engine (CE) starting the combustion engine (CE);- at least one controller (C) connected to the main starting unit (AD), the emergency starting unit (D), the reversible coupling (E2), the electric machine (ME), and the traction battery, said controller (C) detecting a malfunction of the main starting unit (AD) and activating a start by the emergency starting unit (D) in the event of a malfunction of the main starting unit (AD), said controller (C) further detecting a malfunction of the emergency starting unit (D), and in the event of a malfunction of both the main starting unit (AD) and the emergency starting unit (D), said controller (C) checks whether the state of charge of the traction battery is above a threshold, and if so, disengages the internal combustion engine (MT), and activates a start-up of the vehicle by said electric machine (ME).;

2. Motor vehicle according to claim 1, characterized in that said controller (C) detects a malfunction of the main starting unit (AD) if a starting command is not implemented by the internal combustion engine (MT) for a period less than a first threshold period, or if several starting commands are not implemented by the internal combustion engine (MT).

3. A motor vehicle according to any one of claims 1 to 2, characterized in that said controller (C) detects a malfunction of the emergency starting means (D), if a starting command is not implemented by the internal combustion engine (MT) for a period less than a second threshold period, or if several starting commands are not implemented by the internal combustion engine (MT).

4. Motor vehicle according to any one of claims 1 to 3, characterized in that, in the event of malfunction of both the main starting unit (AD) and the emergency starting means (D), said controller (C) deactivates the main starting unit (AD) and the emergency starting means (D).

5. Motor vehicle according to any one of claims 1 to 4, characterized in that said controller (C) deactivates the internal combustion engine (MT) to perform driving in pure electric mode.

6. Motor vehicle according to any one of claims 1 to 5, characterized in that said controller (C) limits the discharge power of the traction battery.

7. Motor vehicle according to any one of claims 1 to 6, characterized in that said threshold is between 15 and 25%, and is preferably 20%.

8. A method for checking the starting of a motor vehicle according to any one of claims 1 to 7, characterized in that it comprises the following steps: - an emergency starting step in which a malfunction of the main starting element (AD) is detected and a starting is activated by the emergency starting means (D) in the event of a malfunction of the main starting element (AD); - a starting step by the electric machine in which a malfunction of both the main starting element (AD) and the emergency starting means (D) is detected, in which case it is checked whether the state of charge of the traction battery is above a threshold, and if so, the internal combustion engine (MT) is disengaged, and a vehicle start-up is activated by said electric machine (ME).

9. A starting control method according to claim 8, characterized in that in the starting step by the electric machine, the main starting element (AD) and the backup starting means (D) are deactivated.

10. Computer program comprising program code instructions for performing the steps of the startup control method according to any one of claims 8 to 9, when said program is running on a computer.

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