Method for supervising a wheel torque for a powertrain

Abstract

The invention relates to a method for supervising the torque of a hybrid powertrain (10) of a motor vehicle, the method comprising: - a step of determining an actual wheel torque taking into account a torque from the first torque producer (11), a torque from the second torque producer (15), a torque at the primary shaft (16.1, 16.1'), a state of the clutch (K0) for connecting and disconnecting the first torque producer (11) and a state of the clutch (K0, K1) for the gearbox (16); - a step of comparing the actual wheel torque with a wheel torque requested by the driver; and - a step of triggering a corrective event if a difference between the actual wheel torque and the wheel torque requested by the driver is greater than a threshold.

Description

DESCRIPTION TITLE: METHOD FOR MONITORING WHEEL TORQUE FOR A POWERTRAIN

[0001] The present invention claims priority from French application No. 2306110 filed on 06 / 15 / 2023, the content of which (text, drawings and claims) is incorporated herein by reference.

[0002] The present invention relates to a method for monitoring wheel torque for a powertrain. The invention finds a particularly advantageous application with hybrid powertrains of two- or four-wheel drive motor vehicles.

[0003] As is known per se, a hybrid powertrain for a motor vehicle may comprise different torque-producing components such as a rotating electric machine and a thermal engine associated with a gearbox via a clutch.

[0004] As illustrated in Figure 1, the software architecture of an engine computer is based on a first functional level N1 implementing algorithms for determining torque levels and a torque distribution between the torque-producing components, as well as a second supervision level N2 configured to detect random or systematic errors made at functional level N1 that may lead to a dangerous event and to apply a reconfiguration to avoid this risk. Levels N1 and N2 receive signals from other computer systems in the vehicle as well as sensor signals at input EE.

[0005] The first functional level N1 comprises a plurality of functional modules MF1-MF8 described in more detail with Figure 2 and a diagnostic module MD1 capable of reconfiguring or inhibiting a functional module in the event of error detection. The functional modules MF1-MF8 communicate with the computers Ci of the torque-producing components and the gearbox to submit to them in particular torque and / or speed requests.

[0006] The MF1-MF8 functional modules also send requests to Ai actuators in the powertrain, such as the combustion engine injectors, a throttle body that manages the amount of air entering the cylinders, or a parking brake.

[0007] The second level of supervision N2 includes a Mint interface module capable of routing signals from the MF1-MF8 functional modules to MS1-MS8 supervision modules configured to perform diagnostic calculations of the MF1-MF8 functional modules. An MD2 diagnostic module manages requests for reconfiguration and / or communication cutoff from the engine ECU to a Mcor corrective module based on the diagnostics performed by the MS1-MS8 supervision modules.

[0008] An external diagnostic tool Oext is able to retrieve fault codes generated by the MD2 diagnostic module.

[0009] More precisely, as can be seen in Figure 2, the first functional level N1 comprises a gear lever management module MF1 capable of selectively taking a position R (for “Reverse” in English) corresponding to reverse gear, a position N corresponding to the neutral position, or a position D (for “Drive” in English) corresponding to the forward gear of the vehicle. The management module MF1 therefore receives as input a signal S_lv representative of the position of the gear lever.

[0010] The MF2 functional module allows for an estimation of the speed and torque of torque-producing components.

[0011] The MF3 functional module allows the determination of the torque limitations of the torque-producing components which will be taken into account later when determining the torque distribution between the torque-producing components.

[0012] The MF4 functional module allows the determination of a torque level desired by the driver depending on the pressure on the accelerator pedal P_acc.

[0013] The MF5 functional module allows torque distribution between torque-producing components.

[0014] The MF6 functional module ensures torque smoothing to optimize driving pleasure.

[0015] The ESP (Electronic Stability Program) driving assistance system indicates to the MF7 functional module a level of torque to add or deduct to ensure the stability of the vehicle during a driving phase on wet ground in particular. The MF7 functional module then estimates a torque of the gearbox input shaft.

[0016] The transmission computer or TCU (for Transmission Control Unit in English) manages the torque levels transmitted by the clutches.

[0017] The MF8 functional module distributes torque between the combustion engine and the rotating electrical machine after taking into account torque smoothing, torque adaptation managed by the ESP system and the torque transmitted by the clutches. The MF8 module then controls the combustion engine and the rotating electrical machine accordingly.

[0018] The N2 supervision level controls monitor the main torque outputs of each MF1-MF8 functional module, from the interpretation of the torque request by the driver to the torque applied by the torque producers 11, 15. Each MF1-MF8 functional module in the torque structure is thus monitored by a corresponding MS1-MS8 supervision module to ensure that the functional module does not make a calculation error.

[0019] Thus, an MS1 ​​supervision module monitors the management of the gear lever carried out by the MF1 functional module.

[0020] The MS2 supervision module monitors the estimation of speed and torque of the torque-producing components carried out by the functional module

[0021] The MS3 supervision module monitors the determination of the torque limitations of the torque-producing components calculated by the MF3 functional module.

[0022] The MS4 supervision module monitors the determination of the torque level desired by the driver based on a press on the accelerator pedal P_acc made by the MF4 functional module.

[0023] The MS5 supervision module monitors the torque distribution between the torque-producing components calculated by the MF5 functional module.

[0024] The MS6 supervision module monitors the torque smoothing carried out by the MF6 functional module.

[0025] The MS7 supervision module monitors the gearbox input shaft torque estimation performed by the MF7 functional module.

[0026] The MS8 supervision module monitors the torque distribution between the thermal engine and the rotating electrical machine controlled by the MF8 functional module.

[0027] The MD21 module manages the diagnostics issued by the MS1-MS8 supervision modules. The MD22 modules handle the processing of engine ECU reconfiguration and communication cut-off requests.

[0028] However, once the verification has been carried out by a given supervision module MS(n), the following supervision module MS(n+1) does not take as input the output of the supervision module MS(n) but the output of the functional module MF(n).

[0029] The existing system therefore does not allow for the detection of several consecutive torque determination errors below a detection threshold. The sum of all these errors can lead to a final torque output higher than the torque desired by the driver, which is likely to make the vehicle's behavior dangerous.

[0030] The invention aims to effectively overcome this drawback by proposing a method for monitoring the torque of a hybrid powertrain of a motor vehicle comprising at least one first torque producer, and a gearbox associated with at least one clutch and comprising at least one primary shaft and one secondary shaft intended to be connected to at least one wheel of a motor vehicle, a second torque producer, a clutch for connecting and disconnecting the first torque producer being capable of selectively connecting the first torque producer to the gearbox when said clutch is in the closed state and of isolating the first torque producer from the gearbox when said clutch is in the open state, said method comprising: - a step of determining an actual wheel torque taking into account a torque of the first torque producer, a torque of the second torque producer, a torque at the primary shaft, a state of the connection and disconnection clutch of the first torque producer, and a state of the gearbox clutch, - a comparison step between the actual wheel torque and a wheel torque requested by the driver, and - a step for triggering a corrective event in the event that a difference between the actual wheel torque and the wheel torque requested by the driver is greater than a threshold.

[0031] The invention thus makes it possible, by directly monitoring the torque at the wheel, to avoid the accumulation of small errors in the torque demand leading to a dangerous event, such as involuntary acceleration. The invention also makes it possible to reduce the complexity of the system, which results in greater robustness in the implementation of the method according to the invention.

[0032] According to one implementation of the invention, the first torque producer being a heat engine and the second torque producer being a rotating electric machine, the actual wheel torque Cwr is determined by the following formula: Cwr=((Cmth*Et_K0 + Cmel)* Et_cl_K1 / K2+ Cprim*Et_sl_K1 / K2) - Cmth being the torque of the thermal engine, - Et_K0 being a value corresponding to the state of the connection and disconnection clutch of the thermal engine being 1 when the connection and disconnection clutch of the thermal engine is closed and 0 when the connection and disconnection clutch of the thermal engine is open, - Cmel being the torque of the rotating electric machine, - Et_cl_K1 / K2 corresponding to the closing state of the gearbox clutch being 1 when the gearbox clutch is closed and 0 when the gearbox clutch is open, - Cprim being the torque at the primary shaft of the gearbox, - Et_sl_K1 / K2 corresponding to the slip state of the gearbox clutch being 1 when the gearbox clutch is slipping and 0 when the gearbox clutch is open or closed.

[0033] According to an implementation of the invention, in the case where the gearbox clutch is closed, then Et_cl_K1 / K2 corresponding to the closing state of the gearbox clutch is equal to 1 and Et_sl_K1 / K2 corresponding to the slipping state of the gearbox clutch is equal to 0.

[0034] According to an implementation of the invention, in the case where the gearbox clutch is open, then Et_cl_K1 / K2 corresponding to the closing state of the gearbox clutch is equal to 0 and Et_sl_K1 / K2 corresponding to the slipping state of the gearbox clutch is equal to 0.

[0035] According to an implementation of the invention, in the case where the gearbox clutch is slipping, then Et_cl_K1 / K2 corresponding to the closing state of the gearbox clutch is equal to 0 and Et_sl_K1 / K2 corresponding to the slipping state of the gearbox clutch is equal to 1.

[0036] According to one implementation of the invention, the torque of the thermal engine is estimated by an engine computer, the torque of the rotating electrical machine is estimated by a computer of the rotating electrical machine, and the torque at The level of the gearbox primary shaft is estimated by a transmission computer.

[0037] According to one implementation of the invention, the corrective event is a reconfiguration of an engine computer implementing said method.

[0038] According to one implementation of the invention, the corrective event is a communication outage of an engine computer implementing said method.

[0039] The invention also relates to an engine calculator comprising a memory storing software instructions for implementing the method as previously defined.

[0040] The invention further relates to a motor vehicle comprising an engine computer as defined above.

[0041] 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.

[0042] [Fig. 1] Figure 1, already described, is a high-level functional diagram of a torque management software architecture carried out by an engine computer according to the state of the art;

[0043] [Fig. 2] Figure 2, already described, is a low-level functional diagram of a torque management software architecture carried out by an engine computer according to the state of the art;

[0044] [Fig. 3] Figure 3 is a schematic representation of a powertrain implementing a method according to the invention for monitoring a wheel torque;

[0045] [Fig. 4] Figure 4 is a low-level functional diagram of a torque management software architecture performed by an engine computer according to the invention.

[0046] Figure 3 shows a hybrid powertrain 10 of a motor vehicle comprising a first torque producer, such as a heat engine 11 and an electric transmission device 12 mounted on a wheel set 13, in particular a front wheel set.

[0047] The electric transmission device 12 comprises a second torque producer, such as 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.

[0048] The gearbox 16 comprises at least one primary shaft 16.1, 16.1' and one secondary shaft 16.2. In this case, the gearbox 16 comprises a first primary shaft 16.1 associated with a first set of gear ratios, for example gear ratios 1-3-5, and connected to the clutch K1. A second primary shaft 16.1' is associated with a second set of gear ratios, for example gear ratios 2-4-6-7, and connected to the clutch K2. The secondary shaft 16.2 of the gearbox 16 is connected to the wheels via a differential and a lowering axle (not shown).

[0049] The KO clutch is a clutch for connecting and disconnecting the heat engine 11. The KO clutch is capable of selectively connecting the heat engine 11 to the gearbox 16 when said KO clutch is in the closed state and of isolating the heat engine 11 from the gearbox 16 when said KO clutch is in the open state. When a torque from the heat engine 11 is transmitted to the wheels, the KO clutch is closed and the clutches K1 and K2 are alternately closed depending on the gear engaged. For this purpose, the KO clutch is arranged between the heat engine 11 and the rotating electrical machine 15. The isolation of the heat engine 11 from the gearbox 16 and therefore from 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.

[0050] The rotating electrical machine 15 is mounted between the clutch KO and the clutches K1, K2 for changing gears of the gearbox 16. The rotating electrical machine 15 can be connected to the input of the gearbox 16 via a belt or chain reduction assembly 18.

[0051] The rotating electrical machine 15 is capable of transforming electrical energy from a traction battery 19 into mechanical energy to provide traction of the vehicle by providing torque to the wheels of 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 making it possible to recharge the traction battery 19, in particular during a regenerative braking phase.

[0052] An engine computer 21 provides wheel torque supervision via a MSgen supervision module explained in more detail below. The engine computer 21 comprises a memory storing software instructions for implementing the wheel torque supervision method according to the invention.

[0053] The engine computer 21 is capable of controlling the torque of the engine 11, the electric machine 15, as well as the clutches KO, K1 and K2. Figure 4 is a low-level functional diagram of a torque management software architecture carried out by the engine computer 21.

[0054] A first functional level N1 comprises a gear lever management module MF1 capable of selectively taking a position R (for “Reverse” in English) corresponding to reverse gear, a position N corresponding to the neutral position, or a position D (for “Drive” in English) corresponding to the forward gear of the vehicle. The management module MF1 therefore receives as input a signal S_lv representative of the position of the gear lever.

[0055] A functional module MF2 makes it possible to estimate the speed and torque of the torque-producing components 11, 15.

[0056] A functional module MF3 makes it possible to determine the torque limitations of the torque-producing organs 11, 15 which will be taken into account later when determining the torque distribution between the torque-producing members 11, 15.

[0057] An MF4 functional module makes it possible to determine a torque level desired by the driver depending on the pressure on the accelerator pedal P_acc.

[0058] A functional module MF5 allows torque distribution between the torque-producing components 11, 15.

[0059] An MF6 functional module ensures torque smoothing to optimize driving pleasure.

[0060] A driving assistance system of the ESP type (for "Electronic Stability Program" in English) indicates to the functional module MF7 a level of torque to add or deduct to ensure the stability of the vehicle during a driving phase on wet ground in particular. The functional module MF7 then estimates a torque of the primary shaft 16.1, 16.1' of the gearbox 16.

[0061] A transmission computer or TCU (for "Transmission Control Unit" in English) allows you to manage the torque levels transmitted by the clutches KO, K1, K2.

[0062] The functional module MF8 performs a torque distribution between the thermal engine 11 and the rotating electrical machine 15 after taking into account the torque smoothing, the torque adaptation managed by the ESP system and the torque transmitted by the clutches. The module MF8 then controls the thermal engine 11 and the rotating electrical machine 15 accordingly.

[0063] The controls of a supervision level N2 monitor the main outputs of the functional modules MF1-MF8, from the interpretation of the torque request by the driver to the torque applied by the torque producers 11, 15.

[0064] In this case, a supervision module MS1 monitors the management of the gear lever carried out by the functional module MF1.

[0065] A supervision module MS2 monitors the estimation of speed and torque of the torque-producing components 11, 15 carried out by the functional module MF2.

[0066] An MS3 supervision module monitors the determination of the torque limitations of the torque-producing components 11, 15 calculated by the MF3 functional module.

[0067] An MS4 supervision module monitors the determination of the torque level desired by the driver based on a press on the accelerator pedal P_acc carried out by the MF4 functional module

[0068] An MS5 supervision module monitors the torque distribution between the torque-producing components calculated by the MF5 functional module.

[0069] An MS6 supervision module monitors the torque smoothing carried out by the MF6 functional module.

[0070] A supervision module MSgen determines a real wheel torque Cwr taking into account a torque of the thermal engine 11, a torque of the rotating electrical machine 15, a torque at the level of the primary shaft 16.1, 16.1', a state of the clutch KO for connecting and disconnecting the first torque producer 11, and a state of the clutch KO, K1 of the gearbox 16.

[0071] The MSgen module compares the actual wheel torque Cwr with a wheel torque requested by the driver Cwd.

[0072] The MSgen module triggers a corrective event in the event that a difference between the actual wheel torque Cwr and the wheel torque requested by the driver Cwd is greater than a threshold. The corrective event may be a reconfiguration of the engine computer 21 or a communication interruption of the engine computer 21 with the components of the powertrain 10.

[0073] Preferably, the actual wheel torque Cwr is determined by the following formula: Cwr=((Cmth*Et_K0 + Cmel)* Et_cl_K1 / K2+ Cprim*Et_sl_K1 / K2) - Cmth being the torque of the thermal engine, - Et_K0 being a value corresponding to the state of the clutch KO for connecting and disconnecting the thermal engine 11, being 1 when the clutch is closed and 0 when the clutch is open, - Cmel being the torque of the rotating electric machine 15, - Et_cl_K1 / K2 corresponding to the closing state of the clutch K1, K2 of the gearbox being 1 when the clutch K1, K2 is closed and 0 when the clutch K1, K2 is open, - Cprim being the torque at the primary shaft 16.1, 16.1' of the gearbox 16, - Et_sl_K1 / K2 corresponding to the slip state of the clutch K1, K2 of the gearbox being 1 when the clutch K1, K2 is slipping and 0 when the clutch K1, K2 is open or closed.

[0074] In the case where the clutch K1, K2 of the gearbox is closed Et_cl_K1 / K2 corresponding to the closing state of the clutch K1, K2 of the gearbox is 1 and Et_sl_K1 / K2 corresponding to the slipping state of the clutch K1, K2 of the gearbox is 0.

[0075] In the case where the clutch K1, K2 of the gearbox is open, Et_cl_K1 / K2 corresponding to the closing state of the clutch K1, K2 of the gearbox is 0 and Et_sl_K1 / K2 corresponding to the slipping state of the clutch K1, K2 of the gearbox is 0.

[0076] In the case where the clutch K1, K2 of the gearbox is sliding Et_cl_K1 / K2 corresponding to the closing state of the clutch K1, K2 of the gearbox 16 is 0 and Et_sl_K1 / K2 corresponding to the sliding state of the clutch K1, K2 of the gearbox is 1.

[0077] Advantageously, the torque of the thermal engine Cmth is estimated by the engine computer 21. The torque of the rotating electrical machine Cmel is estimated by a computer of the rotating electrical machine 15, and the torque at the level of the primary shaft Cprim of the gearbox 16 is estimated by a transmission computer.

[0078] Alternatively, the first torque producer 11 may be a rotating electric machine or a hydrogen engine. Alternatively, the second torque producer 15 may be a heat engine or a hydrogen engine.

Claims

CLAIMS 1. Method for monitoring the torque of a hybrid powertrain (10) of a motor vehicle comprising at least one first torque producer (11), and a gearbox (16) associated with at least one clutch (K1, K2) and comprising at least one primary shaft (16.1, 16.1') and a secondary shaft (16.2) intended to be connected to at least one wheel of a motor vehicle, a second torque producer (15), a clutch (KO) for connecting and disconnecting the first torque producer (11) being capable of selectively connecting the first torque producer (11) to the gearbox (16) when said clutch (KO) is in the closed state and of isolating the first torque producer (11) from the gearbox (16) when said clutch (KO) is in the open state, characterized in that said method comprising: - a step of determining an actual wheel torque (Cwr) taking into account a torque of the first torque producer (11), a torque of the second torque producer (15), a torque at the primary shaft (16.1, 16.1'), a state of the clutch (KO) for connecting and disconnecting the first torque producer (11), and a state of the clutch (KO, K1) of the gearbox (16), - a comparison step between the actual wheel torque (Cwr) and a wheel torque requested by the driver (Cwd), and - a step for triggering a corrective event in the event that a difference between the actual wheel torque (Cwr) and the wheel torque requested by the driver (Cwd) is greater than a threshold.

2. Method according to claim 1, characterized in that the first torque producer (11) being a heat engine and the second torque producer (15) being a rotating electric machine, the actual wheel torque Cwr is determined by the following formula: Cwr=((Cmth*Et_K0 + Cmel)* Et_cl_K1 / K2+ Cprim*Et_sl_K1 / K2) - Cmth being the torque of the thermal engine, - Et_K0 being a value corresponding to the state of the clutch (KO) for connecting and disconnecting the thermal engine (11) being 1 when the clutch (KO) for connecting and disconnecting the thermal engine is closed and 0 when the clutch (KO) for connecting and disconnecting the thermal engine is open, - Cmel being the torque of the rotating electric machine (15), - Et_cl_K1 / K2 corresponding to the closing state of the clutch (K1, K2) of the gearbox being 1 when the clutch (K1, K2) of the gearbox is closed and 0 when the clutch (K1, K2) of the gearbox is open, - Cprim being the torque at the primary shaft (16.1, 16.1') of the gearbox (16), - Et_sl_K1 / K2 corresponding to the slip state of the clutch (K1, K2) of the gearbox being 1 when the clutch (K1, K2) of the gearbox is slipping and 0 when the clutch (K1, K2) of the gearbox is open or closed.

3. Method according to claim 2, characterized in that in the case where the clutch (K1, K2) of the gearbox is closed, then Et_cl_K1 / K2 corresponding to the closing state of the clutch (K1, K2) of the gearbox is equal to 1 and Et_sl_K1 / K2 corresponding to the slipping state of the clutch (K1, K2) of the gearbox is equal to 0.

4. Method according to claim 2 or 3, characterized in that in the case where the clutch (K1, K2) of the gearbox is open, then Et_cl_K1 / K2 corresponding to the closing state of the clutch (K1, K2) of the gearbox is equal to 0 and Et_sl_K1 / K2 corresponding to the slipping state of the clutch (K1, K2) of the gearbox is equal to 0.

5. Method according to any one of claims 2 to 4, characterized in that in the case where the clutch (K1, K2) of the gearbox is sliding, then Et_cl_K1 / K2 corresponding to the closing state of the clutch (K1, K2) of the gearbox is equal to 0 and Et_sl_K1 / K2 corresponding to the sliding state of the clutch (K1, K2) of the gearbox is equal to 1.

6. Method according to any one of claims 2 to 5, characterized in that the torque of the thermal engine (Cmth) is estimated by an engine computer (21), the torque of the rotating electrical machine (Cmel) is estimated by a computer of the rotating electrical machine (15), and the torque at the level of the primary shaft (Cprim) of the gearbox (16) is estimated by a transmission computer.

7. Method according to any one of claims 1 to 6, characterized in that the corrective event is a reconfiguration of an engine computer (21) implementing said method.

8. Method according to any one of claims 1 to 7, characterized in that the corrective event is a communication outage of an engine computer (21) implementing said method.

9. Engine computer (21) comprising a memory storing software instructions for implementing the method defined according to any one of the preceding claims.

10. Motor vehicle comprising an engine computer (21) defined according to the preceding claim.

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