HYBRID AUTOMOBILE INCLUDING A MEANS FOR MONITORING THE STATUS OF A CLUTCH, METHOD AND PROGRAM BASED ON SUCH A VEHICLE

Abstract

The invention relates to a motor vehicle comprising an internal combustion engine (MT); a clutch (K0); an electric machine (ME); a means for opening / closing the clutch (K0); and at least one controller (eVCU) that verifies the open or closed state of the clutch (K0) according to a corresponding command, by comparing the crankshaft speed to the product of the electric machine (ME) speed multiplied by the gear ratio between the crankshaft and the electric machine (ME); or by comparing a difference between these variables to at least one tolerance value. The invention also relates to a method and a program based on such a vehicle. Figure 2

Description

Title of the invention: HYBRID MOTOR VEHICLE COMPRISING A MONITORING DEVICE ON THE CONDITION OF A CLUTCH, PROCEDURE AND PROGRAM BASED ON SUCH A VEHICLE

[0001] The invention relates to the field of clutch monitoring of two-wheel drive hybrid vehicles, in particular a control of the "open" or "closed" state of the clutch.

[0002] Initially, the applicant used actuators of a main clutch with a state feedback to the powertrain supervisor, i.e. the actuator receives a request to open or close the main clutch from the supervisor; and this actuator returns information to the supervisor when the opening or closing of the main clutch is effective.

[0003] However, the reliability of the information regarding the status of the main clutch is not at the required safety level. Therefore, the inventor has changed the monitoring function for the proper opening or closing of the main clutch.

[0004] Patent CN115214614B describes a system and method for detecting faults in a clutch. To establish its diagnosis, the system relies in particular on speed information at the engine output and the clutch output. However, this patent uses two speed sensors on either side of the clutch to obtain a direct measurement of the rotational speed at the clutch input and a direct measurement of the speed at the clutch output.

[0005] One objective of the present invention is to remedy the defects of the prior art, and in particular to offer a reliable solution for verifying the open or closed state of the clutch of a two-wheel drive hybrid vehicle without requiring the addition of additional sensors.

[0006] To achieve this objective, the invention proposes a motor vehicle comprising: - a thermal engine equipped with a crankshaft; - a clutch connected to the internal combustion engine; - an electric machine equipped with a rotor, connected to the clutch; - a gearbox connected to the electric machine; - at least one means of controlling the opening / closing of the clutch; - at least one controller connected to the internal combustion engine; to the electric machine, and an audit means of clutch opening / closing control; characterized in that said controller verifies the open or closed state of the clutch in accordance with a corresponding command, by comparing the rotational speed of the crankshaft to the product of the rotational speed of the electric machine rotor multiplied by the gear ratio between the crankshaft and the electric machine rotor; or by comparing a difference between the rotational speed of the crankshaft and the product of the rotational speed of the electric machine rotor multiplied by the gear ratio between the crankshaft and the electric machine rotor, to at least a tolerance value.

[0007] Advantageously, the invention provides a control of the "open" or "closed" state of the main clutch allowing it to be verified with certainty that the opening or closing of the main clutch has been carried out after the command sent by the powertrain supervisor.

[0008] The purpose of this invention is to protect the integrity of the hybrid powertrain: both the internal combustion engine, but also the gearbox and the electric machine.

[0009] Preferably, when the internal combustion engine is off and the vehicle is moving, if the crankshaft rotation speed is less than or equal to the product of the rotation speed of the electric machine rotor multiplied by a first coefficient and by the reduction ratio between the crankshaft and the electric machine rotor, then the controller considers that the clutch is open in accordance with an opening command; otherwise, the controller considers that the clutch is not open contrary to an opening command.

[0010] This allows confirmation of an opening command in this specific situation.

[0011] Preferably, when the internal combustion engine is running and the vehicle is not moving, if the crankshaft speed is greater than or equal to the product of the electric machine rotor speed multiplied by a second coefficient and by the gear ratio between the crankshaft and the electric machine rotor, then the controller considers that the clutch is open in accordance with an opening command; otherwise, the controller considers that the clutch is not open contrary to an opening command.

[0012] This allows confirmation of an opening command in this specific situation.

[0013] Preferably, when the internal combustion engine is running and the vehicle is moving, if the difference between the crankshaft speed and the product of the electric machine rotor speed multiplied by the gear ratio between the crankshaft and the electric machine rotor is greater than a first tolerance value, then the controller considers the clutch to be open in accordance with an opening command. Otherwise, the controller considers that the clutch is not open, contrary to an opening command.

[0014] This allows confirmation of an opening command in this specific situation.

[0015] Preferably, when the internal combustion engine is off and the vehicle is moving, if the difference between the crankshaft speed and the product of the electric machine rotor speed multiplied by the gear ratio between the crankshaft and the electric machine rotor is less than a second tolerance value, then the controller considers the clutch to be closed in accordance with a closing command; otherwise, the controller considers the clutch to be open contrary to a closing command.

[0016] This allows a closing command to be confirmed in this specific situation.

[0017] Preferably, when the internal combustion engine is on and the vehicle is not moving, if the difference between the crankshaft speed and the product of the electric machine rotor speed multiplied by the gear ratio between the crankshaft and the electric machine rotor is less than a third tolerance value, then the controller considers that the clutch is closed in accordance with a closing command; otherwise, the controller considers that the clutch is not closed contrary to a closing command.

[0018] This allows a closing command to be confirmed in this specific situation.

[0019] Preferably, when the internal combustion engine is on and the vehicle is moving, if the difference between the crankshaft speed and the product of the electric machine rotor speed multiplied by the gear ratio between the crankshaft and the electric machine rotor is less than a fourth tolerance value, then the controller considers that the clutch is closed in accordance with a closing command; otherwise, the controller considers that the clutch is not closed contrary to a closing command.

[0020] This allows a closing command to be confirmed in this specific situation.

[0021] Preferably, in the event of a failure to open the clutch, said controller prevents the stopping of the internal combustion engine; and in the event of a failure to close the clutch, said controller stops the internal combustion engine and limits the power allocated to the electric machine.

[0022] This allows the vehicle to continue moving even in the event of a fault.

[0023] The invention further relates to a method for controlling a motor vehicle according to the invention, comprising at least one clutch verification step in which the open or closed state of the clutch is checked in accordance with a corresponding command, by comparing the crankshaft speed to the product of the electric machine rotor speed multiplied by the gear ratio between the crankshaft and the electric machine rotor; or by comparing a difference between the crankshaft speed and the product of the electric machine rotor speed multiplied by the gear ratio between the crankshaft and the electric machine rotor, to at least a tolerance value

[0024] Another object of the invention relates to a computer program comprising program code instructions for executing the steps of the control process according to the invention, when said program is running on a computer.

[0025] The invention will be further detailed by describing non-limiting embodiments, and based on the accompanying figures, among which: - [Fig. 1] schematically illustrates a first powertrain architecture suitable for implementing the invention; and - [Fig.2] schematically illustrates a second powertrain architecture suitable for implementing the invention.

[0026] The invention proposes a hybrid motor vehicle having a hybrid powertrain architecture, for example of the PHEV type illustrated in [Fig.1]; or an MHEV type architecture illustrated in [Fig.2].

[0027] The PHEV architecture consists of: - an automatic gearbox BV 1; - connected to an electric machine ME1 via a clutch El; - connected to an MT1 internal combustion engine via a main clutch E2; and - an AD alternator-starter connected to the MT1 internal combustion engine via an accessory belt.

[0028] The MHEV-type architecture consists of: - a MT internal combustion engine; - connected to a CP coupling to filter the acyclicities of the internal combustion engine MT in order to reduce the noises of the gearbox BV (shot) and the humming inside the vehicle which originates from the engine acyclicity MT transmitted to the wheels RA of the vehicle; - itself is connected to a main clutch (here called KO), which, when open, allows the internal combustion engine (MT) to be isolated when the eVCU supervisor decides that the optimum is to drive in pure electric mode (or when the user requests driving in pure electric mode) without having to overcome the friction torque of the internal combustion engine (MT). (The KO clutch also allows the internal combustion engine to be started.) with a starter or an alternator-starter: when the vehicle is running in hybrid mode or in pure thermal mode, the KO clutch is closed; - after this KO clutch is the ME electric machine which is connected to the input of the BV gearbox by a chain (alternatively this electric machine can be connected to the input of the gearbox by a cascade of gears or a belt).

[0029] This electric machine ME is powerful enough 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 operate as an electric motor during vehicle traction phases and as an alternator during vehicle deceleration phases and / or battery charging phases.

[0030] Next comes the gearbox BV which can be a dual clutch gearbox (known as DCT), a piloted gearbox or an automatic gearbox.

[0031] In the illustration in [Fig. 2], this is a dual-clutch transmission (with a K1 clutch and a K2 clutch), but if the transmission is a simple automated manual transmission or an automatic transmission, this transmission will have only one clutch between the gearbox teeth and the electric motor. There may even be no clutch between the rear electric motor and the gearbox teeth.

[0032] Next comes, as conventionally, the transverse transmissions connected to the differential which drive the front wheels RA of the vehicle.

[0033] Thus, the main clutch on a hybrid powertrain is the KO clutch, E2, located at the output of the internal combustion engine MT, MT1, which connects this internal combustion engine to the gearbox BV, BV1 or to the electric motor ME, ME1 of said powertrain. This clutch has the ability to disengage the internal combustion engine from the rest of the hybrid drivetrain.

[0034] This clutch is controlled either by the eVCU supervisor of the powertrain or by the gearbox computer BV, BV 1 (which itself is controlled by said eVCU supervisor), the closing and opening of this main clutch KO, E2 is carried out by means of either an electric actuator or a hydraulic stop which opens or closes this clutch.

[0035] Opening this clutch means that the MT, MT1 internal combustion engine is decoupled from the rest of the traction chain and closing this clutch means that the MT, MT1 internal combustion engine is coupled to the rest of the traction chain.

[0036] The invention relates to a "monitoring of the proper functioning of the main clutch actuation" function which can be hosted in the eVCU supervisor of the powertrain or in the BV gearbox computer, BVI, but it could just as easily be housed in another computer. In the context of the invention, we can speak of at least one controller in general.

[0037] In a first case, the "main clutch actuation proper operation monitoring" function verifies that the main clutch is indeed open when the main clutch opening command is sent.

[0038] On the applicant's hybrid vehicles, the eVCU supervisor receives instructions from the driver through information on the depressment of the brake and accelerator pedals (plus possibly the gear lever, if the driver is not in "automatic" mode).

[0039] This eVCU supervisor then controls the electric motor(s) ME, ME1 and the internal combustion engine MT, MT1 to comply with the torque instructions that the driver transmits to it by means of the depressor of the accelerator and brake pedals.

[0040] Thus this eVCU supervisor controls not only the electric machine(s) ME, ME1 and the thermal engine MT, MT1 in torque; but also the main clutch KO, E2, by a state variable (clutch “open” or “closed”).

[0041] The eVCU supervisor receives the rotation regimes: - of the crankshaft (noted "Wmot") via an engine control unit (even if the internal combustion engine MT, MT1 is off), because the internal combustion engine speed sensor is powered as soon as the driver turns the ignition on at the dashboard; - of the primary shaft(s) of the gearbox (noted "Wap" for the primary shaft engaged to move the vehicle forward) via a gearbox computer; - of the electric machine rotor (noted "Wmel") via an electric machine computer.

[0042] It is possible to have a reduction (which we will call here Rmel) between the crankshaft and the rotor of the electric machine ME, ME1 when the electric machine is offset from the primary axis of rotation of the crankshaft.

[0043] However, in reality, if the electric machine ME, ME1 is centered on the primary axis of rotation of the powertrain (as in our example of the PHEV architecture), this means that Rmel is equal to 1.

[0044] Generally, the primary shafts of the BV gearbox are on the primary axis of rotation of the powertrain, so they do not have a reduction ratio relative to the crankshaft in some cases (ratio noted "Rap" which is equal to 1 in this case).

[0045] This means that when the main clutch E2 is fully closed (in our PHEV example, of course with the secondary clutch El also closed), we have: Wmot = Rmel* Wmel = Rap* Wap

[0046] This means that when the main clutch KO is fully closed (in our example MHEV in [Fig.2], with the clutch Kl closed when it is the shaft primary API which is engaged with the RA wheels of the vehicle or K2 closed when it is the primary clutch AP2 which is engaged with the wheels of the vehicle), we have the above formula.

[0047] Thus, the detection of the correct operation of the "open" clutch takes place as follows:

[0048] In a first situation, if the internal combustion engine MT, MT1 is in the off state and the vehicle is moving, when the eVCU supervisor commands the opening of the main clutch KO, E2, the "main clutch actuation proper operation monitoring" function monitors that after a time Tl, the crankshaft speed is less in absolute speed than Rmel x Wmel, and more specifically: Wmot <coefUabs(Rmel x Wmel)avec : Tl can be calibrated during function development, for example between 250 ms and 750 ms; currently the value of Tl is calibrated at 500 milliseconds; coefl can be calibrated during function development, for example between 0.5 and 1; currently the value of coefl is calibrated at 0.8.

[0049] In a second situation, if the internal combustion engine MT, MT1 is running and the vehicle is stationary, when the eVCU supervisor commands the opening of the main clutch KO, E2, the "main clutch actuation proper operation monitoring" function monitors that after a time T2, the crankshaft speed is greater in absolute speed than Rmel x Wmel, and more specifically: Wmot > coef2*abs(Rmel x Wmel) with: T2 can be calibrated during function development, for example between 250 ms and 750 ms; currently the value of T2 is calibrated at 500 milliseconds; coef2 can be calibrated during function development, for example between 0.8 and 1.2; currently the value of coef2 is calibrated to 1.

[0050] In a third situation, if the internal combustion engine MT, MT1 is in the running state and the vehicle is moving, when the eVCU supervisor commands the opening of the main clutch KO, E2, the "main clutch actuation proper operation monitoring" function monitors that after a time T3, the crankshaft speed is different from the speed at Rmel x Wmel by more than one speed tolerance, and more specifically: abs(Wmot - (Rmel x Wmel)) > TolW3with: T3 can be calibrated during function development, for example between 250 ms and 750 ms; currently the value of T3 is calibrated at 500 milliseconds; TolW3 is calibrable during function development, for example between 80 and 120 rpm; currently the value of TolW3 is calibrated at 100 rpm.

[0051] Now in a second case, the "main clutch actuation proper operation monitoring" function verifies that the main clutch KO, E2 is properly closed when the main clutch closing command is sent.

[0052] In a first situation, if the internal combustion engine MT, MT1 is in the off state and the vehicle is moving (this case is only possible when the gearbox is in neutral or the clutches E1, K1 and K2 are open), when the eVCU supervisor commands the closing of the main clutch KO, E2, the "main clutch actuation proper operation monitoring" function monitors that after a time T4, the crankshaft speed is close to the absolute speed of Rmel x Wmel, and more specifically: abs(Wmot - (Rmel x Wmel)) < TolW4with: T4 can be calibrated during function development, for example between 250 ms and 750 ms; currently the value of T4 is calibrated at 500 milliseconds; TolW4 is calibrable during function development, for example between 40 and 60 rpm; currently the value of TolW4 is calibrated at 50 rpm.

[0053] In a second situation, if the internal combustion engine is running and the vehicle is stationary (this case is only possible when the gearbox is in neutral or clutches E1, K1 and K2 are open), when the eVCU supervisor commands the closing of the main clutch K0, E2, the "main clutch actuation proper operation monitoring" function monitors that after a time T5, the crankshaft speed is close to the absolute speed of Rmel x Wmel, and more specifically: abs(Wmot - (Rmel x Wmel)) < TolW5with: T5 can be calibrated during function development, for example between 250 ms and 750 ms; currently the value of T5 is calibrated at 500 milliseconds; TolW5 is calibrable during function development, for example between 40 and 60 rpm; currently the value of TolW5 is calibrated at 50 rpm.

[0054] In a third situation, if the internal combustion engine MT, MT1 is running and the vehicle is moving, when the eVCU supervisor commands the closure of the main clutch KO, E2, the "main clutch actuation proper operation monitoring" function monitors that after a time T6, the crankshaft speed is close to the absolute speed of Rmel x Wmel, and more specifically: abs(Wmot- (Rmel x Wmel )) < TolW6 with: T6 can be calibrated during function development, for example between 250 ms and 750 ms; currently the value of T6 is calibrated at 500 milliseconds; TolWô can be calibrated during function development, for example between 80 and 120 rpm; currently the TolWô value is calibrated at 100 rpm.

[0055] The variables T1, T2, T3, T4, T5, and T6 can be calibrated to different values. The variables Coef1 and Coef2 can be calibrated to different values. The variables TolW3, TolW4, TolW5, and TolWô can be calibrated to different values.

[0056] The "main clutch actuation proper operation monitoring" function can be operational at all times and as soon as the vehicle ignition is switched on.

[0057] If this function detects that one of the inequalities seen previously is not respected within the allotted time, then the function engages a powertrain reconfiguration mode.

[0058] In a later step, the reconfiguration of the two-wheel drive powertrain may include the following four points:

[0059] The function stores a fault code in the read-only memory of the computer that hosts this function to indicate to the maintenance service that the KO clutch, E2 of the MT, MT1 internal combustion engine has experienced control failures, in order to help the teams diagnose the failure.

[0060] If the fault is a failure of the main clutch KO, E2 to open, the eVCU supervisor prevents the internal combustion engine MT, MT1 from switching to a stop position.

[0061] If the fault is a failure to close the main clutch KO, E2, the eVCU supervisor shuts down the internal combustion engine MT, MT1 as long as the main clutch KO, E2 is faulty; and may limit the electrical power allocated to the electric motor ME, ME1 by a certain percentage of its maximum permitted electrical power (this power reduction being calibrable during the development of the function, but currently, the limitation of this electrical power is at 50% of its maximum permitted electrical power under normal conditions).

[0062] The function can, in both cases, request the stop light to illuminate to ask the driver to stop the vehicle.

[0063] Rehabilitation of the reconfiguration takes place when the user performs a key extinction (i.e. turns off the ignition at the dashboard).

[0064] Conversely, when the fault is corrected, the fault code is not suppressed, but the fault code in question may change from the "permanent fault" state to the "intermittent fault" state. However, if the fault is detected again, the fault code will revert to the "permanent fault" state. Thus, maintenance teams can see that there has been a failure of the "unexpected stalling of the internal combustion engine" type.

[0065] The invention further relates to a method and a program implementing the elements described above. The program can be loaded into the memory of one or more controllers to implement the invention.

Claims

Demands

1. A motor vehicle comprising: - an internal combustion engine (MT; MT1) equipped with a crankshaft; - a clutch (KO; E2) connected to the internal combustion engine (MT; MT1); - an electric machine (ME; ME1) equipped with a rotor, connected to the clutch (KO; E2); - a gearbox (BV; BV1) connected to the electric machine (ME; ME1); - at least one means for opening / closing the clutch (KO; E2); - at least one electronic vehicle control unit (eVCU) connected to the internal combustion engine (MT; MT1), the electric machine (ME; ME1), and said means for opening / closing the clutch; characterized in that said controller (eVCU) checks the open or closed state of the clutch (KO; E2) in accordance with a corresponding command, by comparing the crankshaft rotation speed to the product of the rotation speed of the electric machine rotor (ME; ME1) multiplied by the gear ratio between the crankshaft and the electric machine rotor (ME; ME1);or by comparing a difference between the crankshaft rotation speed and the product of the rotation speed of the electric machine rotor (ME; ME1) multiplied by the gear ratio between the crankshaft and the electric machine rotor (ME; ME1), to at least a tolerance value.;

2. Motor vehicle according to claim 1, characterized in that when the internal combustion engine (MT; MT1) is off and the vehicle is moving, if the crankshaft rotation speed is less than or equal to the product of the rotation speed of the electric machine rotor (ME; ME1) multiplied by a first coefficient and by the gear ratio between the crankshaft and the electric machine rotor (ME; ME1), then the controller (eVCU) considers that the clutch (KO; E2) is open in accordance with an opening command, otherwise the controller (eVCU) considers that the clutch (KO; E2) is not open contrary to an opening command.

3. Motor vehicle according to any one of claims 1 to 2, characterized in that when the internal combustion engine (MT; MT1) is on and the vehicle is not moving, if the crankshaft speed is greater than or equal to the product of the rotation speed of the electric machine rotor (ME; ME1) multiplied by a second coefficient and by the gear ratio between the crankshaft and the electric machine rotor (ME; ME1), then the controller (eVCU) considers that the clutch (KO; E2) is open in accordance with an opening command, otherwise the controller (eVCU) considers that the clutch (KO; E2) is not open contrary to an opening command.

4. Motor vehicle according to any one of claims 1 to 3, characterized in that when the internal combustion engine (MT; MT1) is started and the vehicle is moving, if the difference between the crankshaft speed and the product of the rotation speed of the electric machine rotor (ME; ME1) multiplied by the gear ratio between the crankshaft and the electric machine rotor (ME; ME1), is greater than a first tolerance value, then the controller (eVCU) considers that the clutch (KO; E2) is open in accordance with an opening command, otherwise the controller (eVCU) considers that the clutch (KO; E2) is not open contrary to an opening command.

5. Motor vehicle according to any one of claims 1 to 4, characterized in that when the internal combustion engine (MT; MT1) is off and the vehicle is moving, if the difference between the crankshaft speed and the product of the electric machine rotor speed (ME; ME1) multiplied by the gear ratio between the crankshaft and the electric machine rotor (ME; ME1), is less than a second tolerance value, then the controller (eVCU) considers that the clutch (KO; E2) is closed in accordance with a closing command, otherwise the controller (eVCU) considers that the clutch (KO; E2) is not closed contrary to a closing command.

6. Motor vehicle according to any one of claims 1 to 5, characterized in that when the internal combustion engine (MT; MT1) is on and the vehicle is not moving, if the difference between the crankshaft speed and the product of the electric machine rotor speed (ME; ME1) multiplied by the gear ratio between the crankshaft and the electric machine rotor (ME; ME1), is less than a third tolerance value, then the controller (eVCU) considers that the clutch (KO; E2) is closed in accordance with a closing command, otherwise, the controller (eVCU) considers that the clutch (KO; E2) is not closed contrary to a closing command.

7. Motor vehicle according to any one of claims 1 to 6, characterized in that when the internal combustion engine (MT; MT1) is started and the vehicle is moving, if the difference between the crankshaft speed and the product of the rotation speed of the electric machine rotor (ME; ME1) multiplied by the gear ratio between the crankshaft and the electric machine rotor (ME; ME1), is less than a fourth tolerance value, then the controller (eVCU) considers that the clutch (KO; E2) is closed in accordance with a closing command, otherwise the controller (eVCU) considers that the clutch (KO; E2) is not closed contrary to a closing command.

8. Motor vehicle according to any one of claims 1 to 7, characterized in that in the event of a failure to open the clutch (KO; E2), said controller (eVCU) prevents the stopping of the internal combustion engine (MT; MT1); and in the event of a failure to close the clutch (KO; E2), said controller (eVCU) stops the internal combustion engine (MT; MT1) and limits the power allocated to the electric machine (ME; ME1).

9. A method for checking a motor vehicle according to any one of claims 1 to 8, comprising at least one clutch check step in which the open or closed state of the clutch (KO; E2) is checked in accordance with a corresponding command, by comparing the crankshaft speed to the product of the rotational speed of the electric machine rotor (ME; ME1) multiplied by the gear ratio between the crankshaft and the electric machine rotor (ME; ME1); or by comparing a difference between the crankshaft speed and the product 14 of the rotational speed of the electric machine rotor (ME; ME1) multiplied by the gear ratio between the crankshaft and the electric machine rotor (ME; ME1), to at least a tolerance value.

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

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