HYBRID MOTOR VEHICLE COMPRISING AN EMERGENCY RESTARTING MEANS, METHOD AND PROGRAM BASED ON SUCH A VEHICLE

Abstract

The invention relates to a motor vehicle comprising:- a heat engine (MT);- a starter member (ST) for said engine (MT);- a first coupling (C1) with a double pendulum damped flywheel connected to said engine (MT);- an electric machine (ME) connected to a second coupling (C2);- a gearbox (BV) connected at the input to the second coupling (C2), and at the output to vehicle wheels (R);- a first clutch (K0) between said couplings (C1, C2), said gearbox (BV) comprising at least one second clutch (K1, K2);- a controller (MC) which determines whether the starter member (ST) is operating; closes the first clutch (K0), and if necessary said second clutch (K1, K2); and activates the electric machine (ME) so as to start the heat engine (MT). 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 MEANS OF RESTARTING RESCUE, METHOD AND PROGRAM BASED ON SUCH A VEHICLE

[0001] The invention relates to the field of starting systems for thermal engines of hybrid vehicles.

[0002] In prior art thermal projects, there is a starting member whose function is to start the thermal engine. In the event that the starting member is damaged and no longer fulfills its starting function, the vehicle becomes immobilized.

[0003] The palliative solution is to use people, or to use another vehicle, to push the vehicle whose starting device no longer plays its role in order to start the vehicle by pushing (generally called "push" starting).

[0004] This is especially possible with manual gearboxes. For automatic gearboxes, the push-start technique does not work, so a breakdown truck is necessary.

[0005] An objective of the present invention is to remedy the defects of the prior art, and in particular to propose a solution for starting hybrid vehicles when a starting member is not working, and to prevent the vehicle from becoming immobilized.

[0006] To achieve this objective, the invention proposes a motor vehicle comprising: - a heat engine; - a starting device connected to the thermal engine; - a first coupling with double pendulum damping flywheel connected to the thermal engine; - an electrical machine connected to a second coupling; - a gearbox connected as input to the second coupling, and as output to vehicle wheels, the gearbox preferably being a dual-clutch gearbox; - a first clutch connecting the first coupling to the second coupling, the gearbox comprising at least one second clutch; - a controller connected to the thermal engine, the first clutch, the electric machine, and the gearbox, the controller including: - a diagnostic means which determines whether the starting organ is working; - at least one coupling control means which closes the first clutch; and if the electric machine is driving the vehicle and said second clutch is closed, then said coupling control means keeps said second clutch closed; and if the vehicle is not driven, then said coupling control means keeps said second clutch open; - an emergency starting means which activates the electric machine so as to start the thermal engine.

[0007] Advantageously, the invention proposes an emergency starting function on hybrid vehicles to allow the thermal engine to start even in the case where the main starting system of the thermal engine is defective, and even with a so-called "automatic" gearbox.

[0008] The invention provides a function which: - firstly identifies whether the main starting organ of the thermal engine is operational or not; - in the event of failure of the main starting device of the thermal engine, the function stops the use of the main starting device of the thermal engine and initiates the use of starting the thermal engine using the front-wheel drive electric machine: this is the emergency mode; - if the thermal engine cannot be started in emergency mode: a thermal engine start failure mode is engaged.

[0009] The benefit is to allow the driver to start his thermal engine, even with a defective main starting system of the thermal engine; and therefore not to leave the driver with a vehicle immobilized on the side of the road because he has a fault on his hybrid vehicle, especially since the push start mode is not possible because the clutch is naturally open on the applicant's hybrid vehicles.

[0010] Preferably, the diagnostic means measures a starting time of the heat engine, determines whether the heat engine reaches a predetermined idle speed in a duration less than a threshold duration; and if so, determines that the starting member is working; and if not, determines that the starting member is not working.

[0011] This makes it possible to effectively determine whether the starter organ is working.

[0012] Preferably, the threshold duration is between 500 ms and 900 ms.

[0013] This makes it possible to determine precisely when the starting device is operating.

[0014] Preferably, the diagnostic means determines that the starter member is not operating after several failed starts with the starter member.

[0015] This makes it possible to simply determine whether the starter organ is working.

[0016] Preferably, the thermal engine is a three-cylinder turbocharged gasoline engine.

[0017] This allows for optimal operation in terms of efficiency, performance, consumption, pollution and life cycle.

[0018] Preferably, the controller further comprises a means for stopping and restarting the thermal engine, characterized in that the controller deactivates the means for stopping and restarting when the diagnostic means determines that the starting member is not working.

[0019] This makes it possible to avoid inconveniences linked to stopping the engine by the stop-start means.

[0020] Preferably, the starting member is an alternator-starter.

[0021] This allows for a silent starter that consumes little fuel and is less polluting.

[0022] The invention further relates to a method for controlling the starting of a motor vehicle according to the invention, comprising the following steps: - a diagnostic step in which it is determined whether the starting device is working; - at least one coupling control step in which the first clutch is closed; and if the electric machine is driving the vehicle and said second clutch is closed, then said second clutch is kept closed; and if the vehicle is not driven, then said second clutch is closed; - an emergency start-up step in which the electric machine is activated in order to start the thermal engine.

[0023] Another subject 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 operates on a computer.

[0024] The invention will be further detailed by the description of non-limiting embodiments, and on the basis of the appended figures illustrating variants of the invention, in which: - [Fig.l] schematically illustrates an architecture of a hybrid vehicle according to a preferred embodiment of the invention; and - [Fig.2] schematically illustrates the means of implementing the vehicle according to the preferred embodiment.

[0025] The invention is preferably based on a mechanical architecture illustrated in [Fig.l]. This mechanical architecture comprises: - an MT thermal engine associated with its ST starting device; - a first Cl coupling; - an electric machine ME connected to a second coupling C2; - a gearbox BV connected at the input to the second coupling C2, and at the output to vehicle wheels R; - a first clutch KO connecting the first coupling Cl to the second coupling C2; - a controller MC connected at least to the heat engine, to the first clutch, to the electric machine, and to the gearbox.

[0026] The MT thermal engine is preferably a three-cylinder turbocharged gasoline engine. Alternatively, the engine may also be naturally aspirated, it may be diesel, and the number of cylinders may be other than 3. However, the optimum in terms of efficiency, performance, consumption, pollution and life cycles is the three-cylinder turbocharged gasoline engine.

[0027] The MT thermal engine is connected to a double pendulum damping flywheel coupling (first coupling C1). This coupling makes it possible to filter as much as possible the acyclisms of the MT thermal engine in order to reduce gearbox noise (shot) and the buzzing inside the vehicle which originates from the acyclism of the MT engine transmitted to the wheels R of the vehicle.

[0028] The first coupling C1 is itself connected to the first clutch KO. When the first clutch KO is open, it makes it possible to isolate the thermal engine MT when the supervisor MC decides that the optimum is to drive in pure electric mode (or when the driver requests driving in pure electric mode) without having to combat the friction torque of the thermal engine MT.

[0029] The KO clutch also makes it possible to start the MT thermal engine with an ST alternator-starter without having any loss of starter torque in the traction chain.

[0030] When the vehicle is running in hybrid or pure thermal mode, the first KO clutch is closed.

[0031] After this first clutch KO is the electric machine ME which is connected to the input of the gearbox BV by a cascade of pinions (second coupling C2).

[0032] This electric machine ME is sufficiently powerful to drive the vehicle in pure electric traction, and it also allows the traction batteries and / or the service battery to be recharged. This electric machine ME can behave as an electric motor in the vehicle traction phases, and as an alternator in the vehicle deceleration phases and / or in the battery recharge phases.

[0033] Next comes the BV gearbox which is a dual-clutch gearbox. These gearboxes have better performance than conventional automatic gearboxes, for very similar longitudinal dynamic performance and driving pleasure.

[0034] This type of gearbox can be recognized by the fact that it has two clutches at the input of the gearbox (K1 and K2): a clutch for even gears, and a clutch for odd gears in the gearbox. The advantage is that, for gear changes, when you are in a gear, you preselect the gear you want (using synchronizations) and you just have to cross the clutch to change gear. This allows you to avoid any loss of torque in the powertrain, and the driver does not realize that the gear change has taken place.

[0035] Next comes, as conventionally, the transverse transmissions connected to the differential which drive the front R wheels of the vehicle. Alternatively, this type of powertrain can be coupled to a transfer case to equip a 4x4 vehicle.

[0036] The different calculators (or C controllers) which intervene on this subject are the following: - the ME electric traction machine computer, generally called the machine control unit or ("MCU" for "machine control unit" in English): and it manages the ME electric traction machine of the vehicle. It is this which exchanges information with the powertrain supervisor; - the powertrain supervisor, generally called the engine computer (or “CMM”), coordinates, controls, commands and supervises the powertrain computers, it also directly controls and pilots the operation of the MT thermal engine.

[0037] Concerning the starting of the MT thermal engine, the main starting member (starter or alternator-starter) drives the crankshaft in rotation up to approximately 200 rpm (which can be considered as the idle speed). As the resistive torque of the thermal engine fluctuates according to the angle of the crankshaft, at the first crankshaft revolution, the engine speed sensor identifies the top dead center of the crankshaft. During the second revolution of the crankshaft, the computer identifies the zone where the engine can inject the fuel and the zone where the spark plug (for the case of gasoline engines) must be supplied to ignite the “air / fuel” mixture to start the MT thermal engine. The shape of the curve of the rotation speed of the crankshaft as a function of time is then characteristic with a peak starting after 400 ms.

[0038] The main starting device ST of the thermal engine MT is the device which is supposed to start the thermal engine MT when a request to start the thermal engine MT is made by the thermal engine computer or by the powertrain supervisor. This main starting device can be: - either a conventional starter; - either a reinforced starter (it's just a starter with reinforced carbon brushes); - or an alternator-starter.

[0039] The invention relates in particular to an emergency starting function on the hybrid vehicles of the MHEV P2 type.

[0040] This function performs the following operations: - step El: firstly identifies whether the main starting device ST of the thermal engine MT is operational or not (implemented by a corresponding means Ml); - steps E2 and E3: in the event of failure of the main starting device ST of the thermal engine MT, the function stops the use of the starting device ST and initiates the use of a start or restart of the thermal engine MT by means of the front-wheel drive electric machine ME: this is the emergency mode (implemented by corresponding means M2, M3); - step E4: if the MT thermal engine cannot be started in emergency mode: a thermal engine start failure mode is engaged.

[0041] In step E1, the emergency start function measures the start time of the MT thermal engine each time the supervisor engages a MT thermal engine start function.

[0042] If the speed of the thermal engine MT has not reached the idle speed in less than a duration criterion (threshold duration), then the emergency starting function considers that the starting of the thermal engine MT by the main starting device ST has failed.

[0043] If the speed of the thermal engine MT has not reached the idle speed within the aforementioned duration criterion, the emergency starting function considers that the starting of the thermal engine MT by the main starting device ST has been successful.

[0044] In the event of successful starting of the thermal engine MT by the main starting device ST, the emergency starting function is put on standby until the next request by the supervisor for a thermal engine start.

[0045] On the other hand, in the event of detection of an unsuccessful start or restart of the thermal engine, the emergency start function requests the illumination of the service indicator light on the dashboard to indicate the detection of a problem in the traction chain. Alternatively, a fault code is stored in the read-only memory of a specific controller (BSI in the applicant's vehicles), to help the maintenance service identify that the supervisor was unable to start or restart the thermal engine using the main starting device ST and that the emergency start function had to use a start via the electric traction machine ME.

[0046] In particular, the threshold duration is a duration criterion entered into the supervisor's read-only memory by the development teams during the operation of developing the emergency start-up function. The order of magnitude of this threshold time can be in the range of 500ms to 900ms inclusive. This threshold duration depends on the characteristics characteristics of the thermal engine (petrol / diesel, 3 cylinders / 4 cylinders, the displacement of the thermal engine etc.)

[0047] Alternatively, it is possible for the emergency start function to consider a start failure after two aborted attempts to start or restart the thermal engine MT with the main starting device ST.

[0048] Now concerning the phase of engaging a start or restart of the thermal engine MT by the electric traction machine ME, two operations are possible depending on the current state of driving of the vehicle by the electric machine ME.

[0049] If the vehicle is not already driven by the electric traction machine ME, then the emergency start function opens the clutches K1 and K2, then closes the clutch KO and controls the computer of the electric traction machine ME so that the electric machine ME rotates the crankshaft at a speed of around 200 rpm. This rotation speed is read by the engine speed sensor.

[0050] Alternatively, this speed can be controlled and read by the computer of the electric machine ME by means of the speed sensor of the rotor of the electric machine multiplied by the gear ratio which exists between the rotation speed of the rotor of the electric machine ME and the rotation speed of the crankshaft of the thermal engine MT.

[0051] If the vehicle is already driven by the electric traction machine ME, then the emergency start function leaves closed the clutch K1 or K2 which is used to drive the vehicle.

[0052] The emergency start function does not change the rotational speed of the electric machine ME, because this rotational speed corresponds to a travel speed of the vehicle desired by the driver. However, the emergency start function controls the closing of the KO clutch, to allow it to perform controlled slippage. In other words, the emergency start function controls the closing of the KO clutch in order to control the rotational speed of the crankshaft. More precisely, it closes the KO clutch gradually as long as the rotational speed of the crankshaft does not reach 200 rpm and gradually reopens the KO clutch if the rotational speed of the crankshaft exceeds 250 rpm.

[0053] Once the MT thermal engine has started, the engine computer resumes control of the thermal engine's speed and torque, while the emergency start function completely closes the KO clutch, so that the vehicle runs in hybrid mode.

[0054] It should be noted that when the emergency starting function had to involve the electric traction machine ME to start the thermal engine MT, it inhibits the engine computer's stop-start function (or "Stop and Start" in English), i.e. the MT thermal engine is then perpetually started, without being able to be stopped by the stop-start function, until the driver switches off the engine using the key or the powertrain stop button.

[0055] Now concerning the third phase, in the event of failure to start the thermal engine MT by means of the electric traction machine ME, the system fails.

[0056] Indeed, if despite the second phase of the emergency start function, the MT thermal engine still does not start, this function declares a failure to start the MT thermal engine.

[0057] In particular, this function requests the illumination of the vehicle stop indicator light on the dashboard; informs the engine computer that the thermal engine MT cannot be started and that the vehicle can no longer be driven except by the electric traction machine ME.

[0058] Alternatively, this function requires the storage in the read-only memory of a controller (BSI) of a fault code, to indicate to the maintenance service that the problem has been encountered, and that the vehicle stop light displayed on the dashboard is due to a failure to start the thermal engine, even with the starting principle of the emergency start function.

[0059] As for the restoration to normal, there are 2 possibilities: - either it is necessary for the user to bring his vehicle to the maintenance service so that they can analyze the problem, find and restore the fault; - either the driver switched off the powertrain operation on the dashboard (via the key or via the start button on the dashboard) and when he switched the ignition back on, the fault did not recur, i.e. the starting of the MT thermal engine returned to operational.

[0060] In the case of the option of applying a fault code: if the maintenance service does not intervene on the vehicle and the starting or restarting of the MT thermal engine is restored, the fault code changes from the “permanent fault” state to “transient fault”. That is to say that the maintenance service will be able to see that this fault has been reported and that it is no longer active: this means that the fault appeared furtively and has restored itself.

[0061] The invention further relates to a control program implementing the method steps described above. The program can be loaded into the memory of a controller of a hybrid vehicle to implement the invention therein.

Claims

Claims

1. Motor vehicle comprising: - a heat engine (MT); - a starter member (ST) connected to the heat engine (MT); - a first coupling (Cl) with a double pendulum damped flywheel connected to the heat engine (MT); - an electric machine (ME) connected to a second coupling (C2); - a gearbox (BV) connected at the input to the second coupling (C2), and at the output to vehicle wheels (R), the gearbox (BV) preferably being a double clutch gearbox; - a first clutch (KO) connecting the first coupling (Cl) to the second coupling (C2), the gearbox (BV) comprising at least one second clutch (Kl, K2); - a controller (MC) connected to the heat engine, to the first clutch, to the electric machine, and to the gearbox, the controller (MC) comprising: - a diagnostic means (Ml) which determines whether the starter member (ST) is operating;- at least one coupling control means (M2) which closes the first clutch (KO); and if the electric machine (ME) is driving the vehicle and said second clutch (Kl, K2) is closed, then said coupling control means (M2) keeps said second clutch (Kl, K2) closed; and if the vehicle is not driven, then said coupling control means (M2) keeps said second clutch (Kl, K2) open; - an emergency starting means (M3) which activates the electric machine (ME) so as to start the heat engine (MT).;

2. Motor vehicle according to claim 1, characterized in that the diagnostic means (Ml) measures a starting time of the thermal engine (MT), determines whether the thermal engine (MT) reaches a predetermined idle speed in a duration less than a threshold duration; and if so, determines that the starting member (ST) is working; and if not, determines that the starting member (ST) is not working.

3. Motor vehicle according to claim 2, characterized in that the threshold duration is between 500 ms and 900 ms.

4. Motor vehicle according to any one of claims 1 to 3, characterized in that the diagnostic means (Ml) determines that the starting member (ST) is not working after several starting failures with the starting member (ST).

5. Motor vehicle according to any one of claims 1 to 4, characterized in that the thermal engine (MT) is a turbocharged three-cylinder gasoline engine.

6. Motor vehicle according to any one of claims 1 to 5, in which the controller further comprises a means for stopping and restarting the thermal engine, characterized in that the controller (MC) deactivates the means for stopping and restarting when the diagnostic means (Ml) determines that the starting member (ST) is not working.

7. Motor vehicle according to any one of claims 1 to 6, characterized in that the starting member (ST) is an alternator-starter.

8. Method for controlling the starting of a motor vehicle according to any one of claims 1 to 7, comprising the following steps: - a diagnostic step (El) in which it is determined whether the starting member (ST) is working; - at least one coupling control step (E2) in which the first clutch (KO) is closed; and if the electric machine (ME) is driving the vehicle and said second clutch (Kl, K2) is closed, then said second clutch (Kl, K2) is kept closed; and if the vehicle is not driven, then said second clutch (Kl, K2) is closed; - an emergency starting step (E3) in which the electric machine (ME) is activated so as to start the heat engine (MT).

9. A computer program comprising program code instructions for performing the steps of the startup control method according to claim 8, when said program is running on a computer.

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