MONITORING OF ENGINE TORQUE SUPPLIED TO THE DRIVE WHEELS OF A LAND VEHICLE WITH A HYBRID POWERTRAIN

Abstract

A monitoring method is implemented in a land vehicle comprising a powertrain with thermal and electric engines and an automated gearbox, designed to supply the drive wheels with a motor torque based on an overall torque setpoint. This method includes a step (10-50) in which the difference between the supplied motor torque and the overall torque setpoint is determined. If this difference exceeds a chosen threshold, the gearbox is placed in neutral to stop the supply of motor torque to the drive wheels. Figure 3

Description

Title of the invention: MONITORING OF THE MOTOR TORQUE SUPPLIED TO THE DRIVE WHEELS OF A LAND VEHICLE WITH A HYBRID POWERTRAIN Technical field of the invention

[0001] The invention relates to land vehicles comprising a hybrid (thermal and electric) powertrain and automated gearbox, and more specifically to the monitoring within such vehicles of the engine torque which is actually supplied to the drive wheels. State of the art

[0002] Some land vehicles (and possibly motor vehicles) include a hybrid powertrain (or PWM) (i.e. with thermal engine(s) and electric engine(s)) and an automated gearbox.

[0003] As those skilled in the art know, in this type of vehicle, it is important that the engine torque, which is supplied by the (hybrid) powertrain to the drive wheels, corresponds as closely as possible to the overall torque command determined by the powertrain control unit and representative of the driver's acceleration intent (usually a function of the accelerator pedal depressed). Indeed, in the absence of such a correspondence (within a certain tolerance), the driver may be disconcerted because the vehicle's behavior does not correspond to their action on the accelerator pedal. This can result in a fear of vehicle malfunction and a reduction in the perceived quality of the vehicle, or even render the vehicle undrivable because it does not respond to the overall torque commands generated according to the accelerator pedal action, which can prove dangerous.

[0004] In current vehicles, it is generally only checked whether the first motor torque supplied by the thermal engine corresponds (within a certain tolerance) to the thermal torque setpoint determined by the engine control unit, and whether the second motor torque supplied by the electric engine corresponds (within a certain tolerance) to the electric torque setpoint determined by the engine control unit.

[0005] Such a verification method offers relatively satisfactory results when the powertrain is in a purely thermal, purely electric, or hybrid torque delivery phase. However, it frequently poses a problem during so-called transient phases, that is, when the powertrain switches from a 100% electric or thermal phase to a hybrid phase, or from a hybrid phase to a 100% thermal or electric phase. Indeed, during these transitional phases it frequently happens that the engine torque actually supplied to the drive wheels does not correspond to the sum of the thermal and electrical torque setpoints, even when taking into account the aforementioned tolerance.

[0006] When a driver reports the mismatch encountered to a service technician, the latter must carry out long and tedious searches for faults (or malfunctions) in the vehicle's computers and in the vehicle's "fault log" to try to find a clue that will allow him to trace the cause of the reported fault, without any guarantee of success.

[0007] The invention therefore aims to improve the situation. Presentation of the invention

[0008] In particular, it proposes for this purpose a monitoring method intended to be implemented in a land vehicle and comprising a powertrain, on the one hand, with thermal and electric drive machines and automated gearbox, and, on the other hand, capable of providing for drive wheels a motor torque as a function of an overall torque setpoint.

[0009] This monitoring method is characterized by the fact that it includes a step in which a difference is determined between the engine torque supplied and the overall torque setpoint, and, if this difference is greater than a chosen threshold, the gearbox is placed in a neutral position in order to stop the supply of engine torque to the drive wheels.

[0010] Thanks to the invention, the establishment of an untimely acceleration of the vehicle is prevented, and therefore there is no longer a risk that the driver will be disturbed by a behavior of the vehicle which does not correspond to his action on the accelerator pedal, which makes it possible to strengthen the safety of the vehicle and its passengers, but also of its environment.

[0011] The monitoring method according to the invention may include other features which may be taken separately or in combination, and in particular:

[0012] - in its step, the gearbox can be placed in its neutral position when the difference is greater than the chosen threshold for at least a first chosen period;

[0013] - in its step, when at least the difference is greater than the chosen threshold, one can also perform in the vehicle at least one auxiliary action which is chosen from placing the gearbox in an unavailable mode, and recording at least one fault code representative of a problem with the engine torque supplied (and therefore of an untimely acceleration of the vehicle);

[0014] - in its step, the chosen threshold may correspond to an acceleration error of the authorized vehicle speed between 1.3 m.s2 and 2 m.s2;

[0015] - in its step, the motor torque supplied can be determined as a function of a angular acceleration of an active primary shaft in the gearbox, of a reduction induced by a gear engaged in the gearbox and of an inertia of a shaft line of the powertrain in the presence of the gear engaged;

[0016] - in the presence of the last option, in its step, the couple can be determined engine supplied by multiplying the angular acceleration of the active primary shaft by the reduction induced by the engaged ratio and by the inertia of the powertrain shaft line in the presence of the engaged ratio;

[0017] - also in the presence of the last option, in its step, one can determine the angular acceleration of the active primary shaft by calculating a ratio between a difference in angular velocities of the active primary shaft measured at two instants separated by a second chosen duration and this second chosen duration.

[0018] The invention also proposes a computer program product comprising a set of instructions which, when executed by processing means, is suitable for implementing a monitoring method of the type presented above, in a land vehicle and comprising a powertrain, on the one hand, with thermal and electric drive machines and automated gearbox, and, on the other hand, suitable for providing for drive wheels a motor torque as a function of an overall torque setpoint, in order to monitor the motor torque supplied.

[0019] The invention also proposes a monitoring device intended to equip a land vehicle and comprising a powertrain, on the one hand, with thermal and electric drive machines and automated gearbox, and, on the other hand, capable of providing for drive wheels a motor torque as a function of an overall torque setpoint.

[0020] This monitoring device is characterized by the fact that it includes at least one processor and at least one memory arranged to perform the operations of determining a difference between the engine torque supplied and the overall torque setpoint, and, if this difference is greater than a chosen threshold, triggering a placement of the gearbox in a neutral position in order to stop the supply of engine torque to the drive wheels.

[0021] The invention also proposes a land vehicle, possibly of the automobile type, comprising:

[0022] - a powertrain, on the one hand, with thermal and electrical drive machines and automated gearbox, and, on the other hand, capable of providing for drive wheels a motor torque that is a function of an overall torque setpoint, and

[0023] - a monitoring device of the type presented above. Brief description of the figures

[0024] Other features and advantages of the invention will become apparent from an examination of the detailed description below, and the accompanying drawings, in which:

[0025] [Fig. 1] schematically and functionally illustrates an example of an embodiment of a land vehicle, comprising a monitoring device according to the invention, and a hybrid powertrain with automated gearbox and associated with a supervisory computer,

[0026] [Fig.2] schematically and functionally illustrates an example of an embodiment of a supervisory computer comprising an example of an embodiment of a monitoring device according to the invention, and

[0027] [Fig.3] schematically illustrates an example of an algorithm implementing a monitoring method according to the invention. Detailed description of the invention

[0028] The invention aims in particular to propose, on the one hand, a monitoring method, and an associated DS monitoring device, intended to allow, within a land vehicle V with a powertrain (or GMP) with a thermal engine MMT and an electric engine MME and an automated gearbox BV, the monitoring of the engine torque cmf supplied to the drive wheels by this GMP.

[0029] In what follows, the land vehicle V is considered, by way of non-limiting example, to be of the automobile type. This is, for example, a car, as illustrated in [Fig. 1]. However, the invention is not limited to this type of land vehicle. It relates in fact to any type of land vehicle comprising a hybrid (thermal and electric) powertrain with an automated gearbox. Thus, it relates to commercial vehicles, motorhomes, minibuses, coaches, trucks, motorcycles, road maintenance vehicles, construction equipment, agricultural machinery, recreational vehicles (snowmobiles, go-karts), and tracked vehicles, for example.

[0030] Furthermore, in what follows, by way of non-limiting example, the electric drive unit (MME) of the powertrain (hybrid) is considered to be associated with at least one rechargeable (or non-rechargeable) BP battery, referred to as the main (or traction or power) battery. However, it could also be associated with a fuel cell (for example, a hydrogen fuel cell).

[0031] In addition, the transmission chain could also allow a four-wheel drive (or 4x4) or 4x2 mode.

[0032] Figure 1 schematically represents a (land) vehicle V comprising a hybrid (thermal and electric) powertrain with an automated gearbox, a CS supervisory computer, and a battery of servitude BS, a main battery (or traction or power battery) BP (here rechargeable), a CV converter, and a DS monitoring device according to the invention.

[0033] The auxiliary battery BS is responsible for supplying electrical power to an on-board electrical system of the vehicle V, supplementing that supplied by the CV converter, which is powered by the main battery BP via a main electrical circuit, and sometimes replacing this CV converter. For example, this auxiliary battery BS may be configured as a very low voltage battery (typically 12 V or 24 V). It is (here) rechargeable at least by the CV converter. In the following, for the sake of non-limiting example, the auxiliary battery BS is considered to be a 12 V lead-acid battery.

[0034] The on-board network is an electrical power supply network to which electrical (or electronic) equipment (or components) that consume electrical energy are coupled.

[0035] The main electrical circuit (or "high voltage" or "power" circuit) is connected, on the one hand, to the main battery BP via an interface device, and, on the other hand, to electronic equipment, such as the CV converter and the electric drive machine MME. It may also optionally allow the main battery BP to be recharged by an external power source temporarily connected to the vehicle V.

[0036] As illustrated in [Fig.1], the transmission chain also includes, here, a drive shaft AM, a first coupling device DC1, a second coupling device DC2, and a transmission shaft AT.

[0037] The operation of the transmission chain (and therefore of the GMP) is supervised by a CS supervision computer.

[0038] The MMT thermal engine comprises a crankshaft (not shown) which is fixedly attached to the drive shaft AM in order to drive the latter (AM) in rotation or to be driven in rotation by this drive shaft AM. This MMT thermal engine is designed to operate in a first operating mode rl to provide, for the drive wheels of the vehicle V, a thermal engine torque cmt which is defined by a thermal torque setpoint cct, for example determined by the supervisory computer CS.

[0039] The operation of the MMT thermal engine is controlled by a CMT thermal engine computer and supervised by the CS supervisory computer. It should be noted that the CMT thermal engine computer and the CS supervisory computer could be part of the same "supercomputer".

[0040] Furthermore, the MMT thermal drive machine is suitable for being coupled to a primary shaft, referred to as the main APP shaft, of the gearbox BV, via at least the first coupling device DC1. The latter (DC1) is designed to deliver a torque from the thermal engine torque cct, in particular (here) for at least one train Tl of driving wheels, when it is at least partially closed (or passing) and therefore when it couples the thermal engine MMT to the gearbox BV (and more precisely to a clutch Ej associated with a primary (secondary) shaft APSj of the latter (BV)).

[0041] It should be noted that the transmission chain may also include an auxiliary coupling device, installed between the thermal engine MMT and the first coupling device DC1, and intended to filter as much as possible the acyclicities of the thermal engine MMT in order to reduce the noises of the gearbox BV (sniffing) and the buzzing in the passenger compartment of the vehicle V. For example such an auxiliary coupling device may include a double pendulum damper flywheel.

[0042] The first coupling device DC1 can be either totally closed (or totally conducting), or totally open (or totally non-conducting), or partially closed (or partially conducting).

[0043] For example, the first coupling device DC1 can be a hydraulic circuit clutch. But it could be of another type.

[0044] For example, the Tl axle can also be located in the front PVV section of the vehicle V. Preferably, and as illustrated, it is coupled to the AT drive shaft via a differential (here, the front one) DV. However, in a variant, this Tl axle could be the one referenced as T2, which is located in the rear PRV section of the vehicle V. The engine torque cmf, which is produced by the powertrain to drive the drive wheels (here, of the front axle Tl), is therefore supplied to these wheels at the output of the differential DV.

[0045] It should be noted that in the example illustrated, but not limited to, in [Fig. 1], the crankshaft of the MMT internal combustion engine is also coupled to a belt, which is itself coupled to a starter-alternator AD that is electrically powered by the auxiliary battery BS (and which can also recharge the latter (BS)). Thus, the starter-alternator AD can supply torque to the belt, which can then supply this torque to the crankshaft to start the MMT internal combustion engine. The MMT internal combustion engine can also be started by the MME electric motor when the first coupling device DC1 is at least partially closed.

[0046] In one variant, the AD alternator-starter can be powered by the main battery BP.

[0047] The electric drive machine MME is capable, when supplied with electrical energy by the main battery BP, of operating according to a second regime r2 to provide an electric motor torque cme defined by a torque setpoint electric cce (for example determined by the CS supervisory computer), here for drive wheels of vehicle V.

[0048] Furthermore, the electric drive machine MME is coupled, downstream of the first coupling device DC1, by the second coupling device DC2, to the main primary shaft APP of the gearbox BV to supply it with the electric motor torque cme that it produces. The electric drive machine MME thus supplies the electric motor torque cme that it produces for the train Tl and / or for the internal combustion engine MMT.

[0049] It should be noted that the electric drive unit MME can also optionally be arranged to recover a torque defined by a setpoint from the vehicle V, for example during a regenerative braking phase, and in this case, this recovered torque can be used to recharge the main battery BP associated with the electric drive unit MME. However, recovery can also be performed on a portion of the internal combustion engine torque cmt supplied by the internal combustion engine MMT.

[0050] The operation of the electric motor machine MME is controlled by an electric machine computer CME, and supervised by the supervisory computer CS.

[0051] The second coupling device DC2 can, for example, include a cascade of gears connecting the electric drive machine MME to the input of the gearbox BV (downstream of the first coupling device DC1).

[0052] It will be understood that when the first coupling device DC1 is at least partially closed, the internal combustion engine MMT is running (and therefore provides internal combustion engine torque cmt), and the gearbox BV is coupled to the transmission shaft AT, the first coupling device DC1 delivers a torque that is added to any electric motor torque cme provided upstream of the gearbox BV by the electric drive machine MME when it is supplied with electrical energy (here) by the main battery BP. When the first coupling device DC1 is fully open, only the electric drive machine MME can provide electric motor torque cme upstream of the gearbox BV during a purely electric driving phase.When the first coupling device DC1 is at least partially closed, the thermal engine MMT is not running, and the gearbox BV is uncoupled from the drive shaft AT, the electric engine MME can, when supplied with electrical energy (here) by the main battery BP, provide an electric motor torque cme which can drive the thermal engine MMT via the first coupling device DC1.

[0053] It should be noted that in the example illustrated, but not limited to, in [Fig. 1], the differential DV is not part of the gearbox BV. However, in an alternative embodiment, it could be part of this gearbox BV.

[0054] For example, the main (or traction or power) battery BP can be of the cellular type. In this case, it comprises electrical energy storage cells, possibly electrochemical (such as lithium-ion (or Li-ion) or Ni-MH or Ni-Cd cells). Also, for example, this main battery BP can be of the 450 V type. However, this is not mandatory. It could alternatively be of the 48 V, 600 V, or 800 V type, for example.

[0055] As indicated above, the BV (automated) gearbox includes at least one primary (here called secondary) shaft APSj which is associated with at least one clutch Ej suitable for being placed in a state chosen from among an open (or decoupled) state, a closed (or coupled) state, and a sliding state.

[0056] In what follows, by way of non-limiting example, the automated gearbox BV is considered to be a dual-clutch (or DCT) gearbox. Consequently, and as illustrated non-limitingly in [Fig. 1], the gearbox BV comprises first APS1 (j = 1) and second APS2 (j = 2) primary shafts, referred to as secondary shafts, first E1 (j = 1) and second E2 (j = 2) clutches, and first SP1 (j = 1) and second SP2 (j = 2) sub-parts dedicated respectively to first and second subsets of gears (for example, 1, 3, and 5, and 2, 4, 6, and possibly 7). These gears have decreasing ratios respectively (starting from the smallest (1)).

[0057] The first clutches E1 and E2 are connected to the main primary shaft APP and coupled respectively to the first secondary primary shafts APS1 and APS2 in order to transfer to them (when they are in the closed or slipping state) the engine torque they receive from the main primary shaft APP via the powertrain. Thus, when the first clutch E1 is in the closed or slipping state, it causes the rotation of the first secondary primary shaft APS1 according to a third operating condition r31, and when the second clutch E2 is in the closed or slipping state, it causes the rotation of the second secondary primary shaft APS2 according to a third operating condition r32.

[0058] It should be noted that in one embodiment the gearbox BV could include only one clutch associated with a single primary secondary shaft.

[0059] The operation of the BV gearbox is controlled by a CB gearbox computer, and supervised by the CS supervision computer.

[0060] As illustrated, but not limited to, in [Fig. 1], the vehicle V also includes an accelerator pedal PA that can be operated (here) by the driver's foot, and has a percentage of depressment from which an overall torque setpoint ccg is defined, which then represents the driver's intention in Regarding vehicle acceleration V, this overall torque setpoint ccg can, for example, be determined by the CS monitoring computer, and the powertrain must supply the drive wheels (here, the front axle Tl) with a motor torque cmf that must correspond (within a certain tolerance) to this overall torque setpoint ccg. To achieve this correspondence, a thermal torque setpoint cct, representing the thermal engine torque cmt that the thermal power unit MMT will have to supply, and an electrical torque setpoint cce, representing the electric motor torque cme that the electric power unit MME will have to supply, are determined based on the overall torque setpoint ccg. This thermal torque setpoint cct is transmitted to the thermal power unit computer CMT, and this electrical torque setpoint cce is transmitted to the electric power unit computer CME.

[0061] As will be seen later, we can determine the motor torque cmf which is actually supplied by the GMP for the drive wheels (here at the output of the DV differential).

[0062] As mentioned above, the invention proposes in particular a monitoring method intended to allow monitoring of the motor torque cmf supplied to the drive wheels (here of the front axle Tl) by the GMP, at the output (here) of the differential DV.

[0063] This monitoring method can be implemented at least partially by the DS monitoring device (illustrated at least partially in Figures 1 and 2), which comprises for this purpose at least one PR1 processor, for example a digital signal processor (or DSP), and at least one first MD1 memory. This DS monitoring device can therefore be implemented as a combination of electrical or electronic circuits or components (or "hardware") and software modules (or "software"). For example, it could be a microcontroller.

[0064] The MD1 memory is RAM-based in order to store instructions for the implementation by the PR1 processor of at least part of the monitoring process. The PR1 processor may comprise integrated (or printed) circuits, or several integrated (or printed) circuits connected by wired or wireless connections. An integrated (or printed) circuit is defined as any type of device capable of performing at least one electrical or electronic operation.

[0065] In the example illustrated, but not limited to, Figures 1 and 2, the DS monitoring device is part of the CS supervisory computer. However, this is not mandatory. Indeed, the DS monitoring device could comprise its own dedicated computer, which could then be coupled to the CS supervisory computer, or it could be part of another computer embedded in the vehicle V and performing at least one other function, for example.

[0066] As illustrated non-limitingly in [Fig.3], the monitoring method, according to the invention, includes a step 10-50 which is implemented when the GMP is in operation to supply the drive wheels (here of the front axle Tl) with motor torque cmf at the output (here) of the differential DV following the generation of an overall torque setpoint ccg.

[0067] Step 10-50 of the monitoring process includes a substep 20 in which the difference between the supplied motor torque cmf and the overall torque setpoint ccg (i.e., de = cmf - ccg) is determined (for example, the monitoring device DS).

[0068] If this difference is less than or equal to a chosen threshold sc (i.e., de < sc), this means that the supplied motor torque cmf corresponds (within a certain tolerance) to the overall torque setpoint ccg, which is normal. Therefore, step 10-50 of the monitoring process ends in substep 40.

[0069] Conversely, if this difference is greater than the chosen threshold sc, it means that the engine torque supplied cmf does not correspond (within a certain tolerance) to the overall torque setpoint ccg, and therefore there will be an unintended (undesired) acceleration of the vehicle V. Consequently, step 10-50 of the monitoring procedure includes a substep 50 in which the gearbox BV is placed (for example, the monitoring device DS triggers the placement of) in its neutral position N (or "neutral"), in order to stop the supply of engine torque cmf to the drive wheels. The vehicle V then very temporarily finds itself in neutral.

[0070] Thus, the system prevents the vehicle V from accelerating unintentionally, and therefore there is no longer any risk of the driver being disturbed by vehicle V's behavior not corresponding to their action on the accelerator pedal PA. The driver therefore no longer has to fear a malfunction of vehicle V, whether the powertrain is in a 100% thermal or 100% electric phase or in a transitional phase (switching from 100% electric or thermal mode to hybrid mode or from hybrid mode to 100% thermal or electric mode). This enhances the safety of vehicle V and its passengers, as well as its surroundings.

[0071] For example, and as illustrated non-limitingly in [Fig. 3], step 10-50 of the monitoring process may include a substep 30 in which the difference (for example, the monitoring device DS) can be compared to the chosen threshold sc. If the difference is less than or equal to the chosen threshold sc, step 10-50 of the monitoring process ends in substep 40. Conversely, if the difference is greater than the chosen threshold sc, substep 50 is carried out.

[0072] Also, for example, in substep 50 of step 10-50, the box can be placed (for example, the DS monitoring device can trigger the placement of) BV speeds in its neutral position when the difference in speed exceeds the chosen threshold (sc) for at least a first chosen duration (dl). This option avoids taking into account a difference in speed exceeding the chosen threshold (sc) for a very short duration resulting, for example, from a single or very brief measurement or calculation error, or from a problem transmitting measurement(s) over an onboard (possibly multiplexed) communication network.

[0073] In this case, when the difference in value is greater than the chosen threshold sc for a duration that is less than or equal to the first chosen duration dl, this is considered normal. Therefore, step 10-50 of the monitoring process ends in substep 40.

[0074] For example, the first duration dl can be between 0.5 s and 1.5 s. As an illustrative example, this first duration dl can be equal to 1 s. But other values ​​for the first duration dl can be used. For example, this first duration dl can be chosen during the development or testing phase of a vehicle similar to vehicle V.

[0075] Also, for example, in substep 50 of step 10-50, when at least the difference in is greater than the chosen threshold sc (for example, for at least the first duration dl), at least one auxiliary action can also be performed in vehicle V (for example, the DS monitoring device can trigger the performance) in addition to the main action of placing the gearbox BV in its neutral position. Each auxiliary action can be chosen from placing the gearbox BV in an unavailable mode, and recording at least one fault code representative of a problem with the engine torque supplied cmf (and therefore of unintended acceleration of vehicle V).

[0076] The temporary placement of the BV gearbox in the unavailable mode is intended to very temporarily prevent a new gear from being engaged in the BV gearbox.

[0077] Recording at least one fault code representative of a problem with the supplied engine torque (cmf) is intended to facilitate troubleshooting the cause of the uncontrolled acceleration problem by after-sales service. It should be noted that the storage of each fault code can, for example, be done in a (possibly read-only) memory of the DS monitoring device or the CS supervisory control unit.

[0078] Also, for example, in substep 30 of step 10-50, the selected threshold sc may correspond to an permissible vehicle acceleration error V of between 1.3 m / s² and 2 m / s². As an illustrative example, this selected threshold sc may be equal to 1.5 m / s². However, other values ​​of the selected threshold sc may be used. For example, this sc threshold can be chosen during the development or testing phase of a vehicle similar to vehicle V.

[0079] It should be noted that the chosen threshold sc can be fixed (and therefore predefined). But in a variant it could be variable, for example depending on the current speed of the vehicle V and / or the gear engaged in the gearbox BV at the moment considered.

[0080] Also, for example, and as illustrated non-limitingly in [Fig. 3], step 10-50 of the monitoring method may include a substep 10 in which the engine torque supplied (for example, the DS monitoring device) can be determined as a function of the angular acceleration aaa of the primary secondary shaft APSj that is active in the gearbox BV at the instant considered, the gear ratio dm induced by the gear engaged in the gearbox BV, and the inertia ila of the powertrain shaft line in the presence of the engaged gear. However, this determination could be made as a function of at least one other parameter besides the three mentioned above (aaa, dm, and ila), either in addition to or instead of them.

[0081] It should be noted that the current reduction ratio dm can, for example, be determined from a lookup table establishing a correspondence between reduction ratios and the different gear ratios. But in an alternative embodiment, the current reduction ratio dm could be determined as a function of at least one mathematical formula having the engaged gear ratio as a parameter.

[0082] It should also be noted that the current inertia ila can, for example, be determined from a lookup table establishing a correspondence between the inertias of the powertrain shaft and the different gear ratios. But in an alternative embodiment, the current inertia ila could be determined as a function of at least one mathematical formula having the engaged gear ratio as a parameter.

[0083] Also, for example, in substep 10 of step 10-50, the engine torque supplied (for example, the DS monitoring device) can be determined by multiplying the angular acceleration aaa of the active secondary primary shaft APSj by the gear ratio dm induced by the engaged ratio and by the inertia ila of the powertrain shaft line in the presence of the engaged ratio, i.e., cmf = aaa*dm*ila. However, this determination could be made using a mathematical formula other than the one mentioned above.

[0084] Also, for example, in substep 10 of step 10-50, one (for example the DS monitoring device) can determine the angular acceleration aaa of the active secondary primary shaft APSj by calculating the ratio between the difference of the angular velocities vaa of the active secondary primary shaft APSj measured at two instants (t and t-1) separated by a second chosen duration d2 (equal to t - (t-1)) and this second chosen duration d2, i.e. aaa = (vaa(t) - vaa(tl)) / d2.

[0085] It should be noted that the angular velocity vaa of each active primary secondary shaft APSj can be measured by a dedicated sensor or by the CB gearbox computer (depending on at least one measurement made by a sensor).

[0086] For example, the second duration d2 can be between 0.5 s and 1.5 s. As an illustrative example, this second duration d2 can be equal to 1 s. But other values ​​for the second duration d2 can be used. For example, this second duration d2 can be chosen during the development or testing phase of a vehicle similar to vehicle V.

[0087] It should also be noted that the vehicle V does not respond correctly to the global torque instructions ccg (generated according to the action on the accelerator pedal PA), and therefore may be undrivable, consideration can be given to alerting the driver when the gearbox BV is placed in its neutral position, so that he can immobilize his vehicle V as quickly as possible.

[0088] The driver may be alerted by the illumination of a warning light (possibly dedicated) on the vehicle V (e.g., on the instrument panel) or by the generation of at least one message. In the case of a message, this may be a text message displayed on at least one screen of the vehicle V (e.g., on the instrument panel or a central instrument cluster) or on the screen of the driver's smartphone and / or an audible message broadcast by at least one speaker of the vehicle V or of that smartphone. This warning message may optionally indicate the reason for the transmission being in neutral (or in the unavailable mode).

[0089] For example, stopping the operation of the GMP followed by restarting the GMP can allow the cessation of the placement of the gearbox BV in its neutral position (or in the unavailable mode).

[0090] It should also be noted, as illustrated but not limited to [Fig. 2], that the CS supervisory computer (or the DS monitoring device computer) may also include a mass memory MEM1, in particular for storing the overall torque setpoint ccg, the engaged gear ratio and any angular velocities vaa, as well as any intermediate data involved in all its calculations and processing. Furthermore, this CS supervisory computer (or the DS monitoring device computer) may also include an IE1 input interface for receiving the overall torque setpoint ccg, the engaged gear ratio and any angular velocities vaa for use in calculations or processing, possibly after having been shaped and / or demodulated and / or amplified, in a manner known per se, by means of a PR2 digital signal processor.In addition, this CS supervisory computer (or the DS monitoring device computer) may also include an IS1 output interface, notably to deliver each message (or . request) intended to place the gearbox BV in its neutral position and each possible message (or request) intended to trigger the execution of at least one auxiliary action.

[0091] It will also be noted that the invention also proposes a computer program product (or computer program) comprising a set of instructions which, when executed by processing means of the type of electronic circuits (or hardware), such as for example the PR1 processor, is suitable for implementing in the vehicle V the monitoring method described above to monitor the engine torque cmf which is supplied to the drive wheels (here of the front axle Tl) by the GMP, at the output (here) of the differential DV.

Claims

Demands

1. A monitoring method for a land vehicle (V) comprising a powertrain, with thermal (MMT) and electric (MME) drive machines and an automated gearbox (BV), and adapted to provide for drive wheels a motor torque as a function of an overall torque setpoint, characterized in that it comprises a step (10-50) in which a difference is determined between said motor torque supplied and said overall torque setpoint, and, if this difference is greater than a chosen threshold, said gearbox (BV) is placed in a neutral position in order to stop the supply of said motor torque to said drive wheels.

2. A monitoring method according to claim 1, characterized in that in said step (10-50) said gearbox (BV) is placed in said neutral position when said difference is greater than said chosen threshold for at least a first chosen duration.

3. A monitoring method according to claim 1 or 2, characterized in that in said step (10-50), when at least said difference is greater than said chosen threshold, at least one auxiliary action is also carried out in said vehicle (V) chosen from a placement of said gearbox (BV) in an unavailable mode, and a recording of at least one fault code representative of a problem with supplied engine torque.

4. A monitoring method according to any one of claims 1 to 3, characterized in that in said step (10-50) said chosen threshold corresponds to an allowed acceleration error of said vehicle (V) of between 1.3 m.s2 and 2 m.s2.

5. A monitoring method according to any one of claims 1 to 4, characterized in that in said step (10-50) said engine torque supplied is determined as a function of an angular acceleration of an active primary shaft in said gearbox (BV), a reduction ratio induced by a ratio engaged in said gearbox (BV) and an inertia of a shaft line of said powertrain in the presence of said ratio engaged.

6. A monitoring method according to claim 5, characterized in that in said step (10-50) said supplied motor torque is determined by multiplying said angular acceleration of the active primary shaft by said gear reduction induced by said engaged ratio and by the said inertia of the drivetrain shaft line in the presence of the said engaged ratio.

7. Monitoring method according to claim 5 or 6, characterized in that in said step (10-50) said angular acceleration of the active primary shaft is determined by calculating a ratio between a difference in angular velocities of said active primary shaft measured at two instants separated by a second chosen duration and said second chosen duration.

8. Product computer program comprising a set of instructions which, when executed by processing means, is suitable for implementing the monitoring method according to any one of claims 1 to 7, in a land vehicle (V) comprising a powertrain, with thermal engine machines (MIM) and electric engine machines (EIM) and automated gearbox (BV), and suitable for providing for drive wheels an engine torque as a function of an overall torque setpoint, for monitoring said engine torque supplied.

9. Monitoring device (DS) for a land vehicle (V) comprising a powertrain, with thermal (MMT) and electric (MME) drive machines and automated gearbox (BV), and capable of providing for drive wheels a motor torque as a function of an overall torque setpoint, characterized in that it comprises at least one processor (PR1) and at least one memory (MD1) arranged to perform the operations of determining a difference between said motor torque supplied and said overall torque setpoint, and, if this difference is greater than a chosen threshold, of triggering a placement of said gearbox (BV) in a neutral position in order to stop the supply of said motor torque to said drive wheels.

10. Land vehicle (V) comprising a powertrain, with thermal (MMT) and electric (MME) drive machines and automated gearbox (BV), and capable of providing for drive wheels a motor torque as a function of an overall torque setpoint, characterized in that it further comprises a monitoring device (DS) according to claim 9.

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