Method for controlling a powertrain of a motor vehicle comprising at least two drive power sources

Abstract

A method for controlling a powertrain of a motor vehicle, the powertrain comprising at least two driving power sources and at least one drive wheel, the method comprising the steps of: - determining a maximum wheel torque tolerance and a minimum wheel torque tolerance with respect to predetermined rules, - determining a wheel torque setpoint from a wheel torque request from a driver or from at least one driving assistance system, - determining a distribution of the wheel torque setpoint between the driving power sources, - checking whether the sum of the wheel torque setpoints for the driving power sources is within the previously determined tolerances with respect to the wheel torque request from the driver, - for each driving power source, checking whether the torque actually delivered to the wheel is within the previously determined tolerances with respect to the torque setpoint for the driving power source, - checking whether the sum of the torque actually delivered to the wheel from each driving power source is also within the previously determined tolerance range with respect to the torque request from the driver, - if at least one of the checks does not pass, issuing a fault signal.

Description

TECHNICAL FIELD

[0001] The technical field of the present invention is controlling a motor vehicle powertrain, and more particularly controlling a hybrid or electric powertrain. BACKGROUND

[0002] The acceleration expected by the driver is the acceleration that is explicitly responsive to a given depression of the accelerator pedal, which depression is generated by the driver's desire.

[0003] In order to drive a vehicle, for example a vehicle provided with an internal combustion engine, at a given acceleration γ, the powertrain of the vehicle must transmit to at least one drive wheel of the vehicle a torque that generates a driving force or power F 动力 such that, according to the fundamental principle of dynamics, the following holds:

[0004] mγ = F 动力 -∑F 阻力

[0005] where:

[0006] m: mass of the vehicle, and

[0007] ∑F 阻力 : sum of the forces that oppose the forward travel of the vehicle.

[0008] The power F 动力 is defined as:

[0009] T 车轮 = F 车轮 x r

[0010] where,

[0011] T 车轮 : wheel torque

[0012] r: radius of the wheel.

[0013] In addition, in the case where the torque comes from a single engine (for example, an internal combustion engine), assuming that the transmission line between the drive source and the wheel is single-output (said transmission line in particular comprising a gearbox with a plurality of gears), the torque transmission equation can be written based on the power conservation between the drive source and the wheel. The following equation is then obtained:

[0014] P 发动机 = P 车轮

[0015] This equation can be re-expressed as follows:

[0016] T 发动机 x ω 发动机 = T 车轮 x ω 车轮

[0017] or:

[0018]

[0019] wherein:

[0020] P 发动机 : engine power,

[0021] P 车轮 : power transmitted to the wheels,

[0022] T 发动机 : engine torque,

[0023] T 车轮 : wheel torque,

[0024] ω 车轮 : rotational speed of the wheels, and

[0025] ω 发动机 : rotational speed of the engine.

[0026] Thus, the following equation can be written:

[0027] F 动力 = T 发动机 / r ω 发动机 / ω 车轮

[0028] wherein ω 发动机 / ω 车轮 is the gear reduction ratio or the inverse of the reduction ratio between the engine and the wheels. This ratio depends in particular on the gears engaged.

[0029] The decomposition of the resistance ∑F 阻力 in particular comprises

[0030] - aerodynamic force

[0031] F a = 0.5 * p * S * C x * V 2

[0032] wherein: p: density of the air,

[0033] S: frontal surface area of the vehicle,

[0034] C x : air resistance coefficient, and

[0035] V: vehicle speed

[0036] - rolling resistance

[0037] F ro = m * g * C rr

[0038] where:

[0039] g: acceleration due to gravity;

[0040] C rr : tire's drag coefficient

[0041] - horizontal component of gravity, for an upward slope:

[0042] F p = m * g * sin(a);

[0043] where:

[0044] a: slope

[0045] In addition to these resistances, there are also inertial forces associated with any mass element X of the driveline, which rotates around an axis and therefore has rotational inertia, such that:

[0046]

[0047] Inertial torque T of mass element X under rotational acceleration in the driveline 惯性.x can be expressed as a function of its rotational speed and its moment of inertia I X :

[0048]

[0049] Next, the corresponding wheel torque ω 车轮 can be expressed in terms of the above torque transmission equation as a function of the wheel rotational speed

[0050]

[0051] or

[0052]

[0053] Angular acceleration of the wheel and the longitudinal acceleration of the vehicle γ are related by the following equation:

[0054]

[0055] Therefore, the following equation can be written:

[0056]

[0057] where:

[0058] is the gear reduction ratio or the inverse of the reduction ratio between the rotating mass element X and the wheel.

[0059] Taking into account these inertia forces F 惯性 , the dynamics fundamental principle can be written as follows:

[0060]

[0061] It should be noted that the term F 惯性 contains the sum of the inertia of all rotating mass elements, i.e. the sum of the inertia of all parts x1, x2,... xi,... xn rotating around an axis in the driveline, the inertia of each rotating mass element being delivered to the wheel.

[0062] Then, the following equation can be written:

[0063]

[0064] This equation can be re-written in torque form as follows.

[0065]

[0066] where:

[0067] F 车轮.惯性 : wheel force of a rotating part,

[0068] T 车轮.惯性 : wheel torque of a rotating part,

[0069] r: radius of the wheel

[0070] ω xi : rotational angular velocity of a part xi of the driveline

[0071] ω 车轮 : rotational angular velocity of the wheel

[0072] m: mass of the vehicle

[0073] γ: longitudinal acceleration of the vehicle

[0074] Ixi: rotational inertia of a part xi of the driveline measured during the mechanical design of the driveline.

[0075] The equation for the dynamics fundamental principle shows that the driving force or power is used to overcome the above-mentioned resistances and to accelerate (or decelerate) the vehicle according to the difference between the sum of the power and the resistances.

[0076] When the vehicle driver depresses the accelerator pedal to a given value, the electronic control unit determines the torque setpoint T 发动机 based on this depression value and the rotational speed of the engine (corresponding to ω 发动机 ).thereby providing a driving force F 动力 and an acceleration γ, the values of which are determined according to the aforementioned (kinetic fundamentals) equation. The engine torque setpoint also depends on the engaged gear.

[0077] In other words, by depressing the accelerator pedal by a given value, the driver expresses their desire to obtain a given vehicle acceleration. This acceleration is a value to which the driver is cognitively accustomed by repeated use of the vehicle. Therefore, the vehicle's acceleration should not differ from this expected acceleration value. More particularly, the vehicle must not exhibit an unexpected and sudden acceleration (or deceleration) difference compared to the value desired by the driver (for example, a difference greater than 1.5 m / s 2 for more than two seconds) that can pose a risk of surprising the driver and causing safety problems.

[0078] There is a need for a method for controlling a powertrain that makes it possible to detect and avoid an unexpected acceleration of a hybrid vehicle, i.e. a vehicle comprising at least two sources of torque, an internal combustion engine and at least one electric machine, for propelling the vehicle.

[0079] Unexpected acceleration means an acceleration that is not expected or anticipated by the driver of the vehicle.

[0080] The following prior art documents are known.

[0081] US 2012310455 discloses a method for controlling the torque output of a hybrid powertrain.

[0082] CN 104176047 discloses a method for monitoring the torque of a hybrid vehicle.

[0083] US 2013073130 discloses a fail-safe control method for a hybrid vehicle.

[0084] US 2015166044 discloses a system and method for controlling the torque of a hybrid vehicle.

[0085] KR 20110033723 discloses a safety system for a hybrid vehicle.

[0086] CN 102774375 and CN 102774377 disclose a method for monitoring the torque of a hybrid vehicle.

[0087] Methods are also known that make it possible to compensate for variations in vehicle acceleration associated with differences in mass or differences in slope, with respect to the expected acceleration of a flat road and a reference load.

[0088] EP 1045121 A1 discloses such a method. This method makes it possible to attenuate the sensation of performance degradation due to driving on an upward slope and / or under significant load, thereby avoiding observing acceleration differences with respect to the expected acceleration under reference conditions (i.e. zero slope, standard load).

[0089] US 20180126936 A1 discloses a method for calibrating an inertial sensor mounted on a vehicle and capable of determining a signal of the vehicle, such as an acceleration. This document states that this signal can be used to trigger in particular safety devices of the vehicle, such as airbags or braking systems, such as ESP.

[0090] None of these documents solve this technical problem. SUMMARY

[0091] The present invention relates to a method for controlling a powertrain of a motor vehicle, the powertrain comprising at least one driven wheel and two driving power sources, the method comprising the steps of:

[0092] - determining a maximum wheel torque tolerance and a minimum wheel torque tolerance with respect to predetermined rules,

[0093] - determining a wheel torque setpoint from a torque request from a driver or from at least one driving assistance system,

[0094] - determining a distribution of the wheel torque setpoint between the driving power sources,

[0095] - checking whether the sum of the wheel torque setpoints for the driving power sources is within the previously determined tolerances with respect to the torque request from the driver,

[0096] - for each driving power source, checking whether the torque actually delivered to the wheel is within the previously determined tolerances with respect to the wheel torque setpoint for this driving power source,

[0097] - checking whether the sum of the torque actually delivered to the wheel from each driving power source is also within the previously determined tolerance range with respect to the wheel torque request from the driver,

[0098] - issuing a fault signal if at least one of the checks does not pass.

[0099] The following steps can be performed to determine the wheel torque setpoint:

[0100] - determining a first wheel torque request from the driver using a first computing device,

[0101] - determining, using the first computing means, a first wheel torque setpoint from the first wheel torque request from the driver and the drive power sources of the powertrain,

[0102] - determining, using second computing means, a second wheel torque request from the driver,

[0103] - determining, using the second computing means, a second wheel torque setpoint from the second wheel torque request from the driver and the drive power sources of the powertrain,

[0104] - checking whether the first wheel torque setpoint and the second wheel torque setpoint are identical, i.e. whether the difference between the two is within the predetermined tolerances,

[0105] - if so, considering that the first wheel torque setpoint is the wheel torque setpoint.

[0106] The actual torque from each drive power source and the torque actually delivered from each drive power source to the wheels can be determined using the first computing means.

[0107] The distribution of the wheel torque setpoint between the drive power sources of the powertrain can depend on requirements relating to energy optimization, driving pleasure, pollution reduction and vehicle reliability.

[0108] The distribution of the wheel torque setpoint can be determined by the first computing means.

[0109] The checking and limiting of the torque setpoint or the actual torque from the at least one drive power source can be determined by the second computing means.

[0110] When issuing a fault signal after the check has not passed, a command to reset the computing means or the at least one drive power source in question can be issued, and the check can then be performed again; if the check still does not pass, a command to limit the torque setpoint or the actual torque from the at least one drive power source in question can be issued.

[0111] The powertrain can be a hybrid powertrain.

[0112] The at least one driving assistance system can comprise a speed controller. BRIEF DESCRIPTION OF DRAWINGS

[0113] Further objects, features and advantages of the application will become clear from the following description, given by way of non-limiting example only, and with reference to the drawings, in which:

[0114] - Figure 1 The main steps of the control method according to the application are illustrated. DETAILED DESCRIPTION

[0115] The control method according to the application applies to a motor vehicle provided with a hybrid powertrain comprising an internal combustion engine and at least one electric machine, or to an electric vehicle comprising at least two electric machines.

[0116] This control method makes it possible to control a powertrain comprising several drive sources (internal combustion engine, hybrid starter-generator, drive electric machine, etc.) to produce torque, while monitoring the risk of unwanted acceleration and deceleration.

[0117] This control method comprises a first step 1 (sub-steps 10, 11, 12, 13, 40, 42) during which the driver's desired wheel torque setpoint is safely established, said safety being relative to the risk of misinterpreting an acceleration or deceleration request from the driver via the accelerator pedal or an acceleration or deceleration request from a driving assistance system. This setpoint is safe relative to an acceptable corresponding maximum wheel torque tolerance and minimum wheel torque tolerance, which does not lead to an abnormally dangerous acceleration (excessive engine torque relative to the driver's request) or deceleration (excessive resistance torque relative to the driver's request).

[0118] During a second step 2 (sub-steps 43, 41, 44, 45), after the control system has calculated the torque setpoint for each drive source of the powertrain, it is checked whether the sum of the contribution of each setpoint to the acceleration or deceleration of the vehicle remains within a previously determined tolerance relative to the acceleration or deceleration torque request from the driver.

[0119] During a third step 3 (sub-steps 30, 31), it is checked whether the sum of the actual contribution of each drive source (i.e. the sum of the torques actually delivered to the wheels from the different drive sources) remains within a previously determined tolerance relative to the acceleration or deceleration torque request from the driver.

[0120] The following definitions apply. Unwanted acceleration is defined as an acceleration produced by the powertrain that exceeds the "driver's expectation", i.e. with a bias added. By "driver's expectation" is meant the acceleration expected when the driver depresses the accelerator pedal. Unwanted deceleration can be defined correspondingly. This acceleration will translate into an excessive torque relative to the driver's expectation.

[0121] In addition, the drive sources can be made safe in various ways, for example by adding mechanical barriers or redundancies (for example, two computers working in parallel), or in this case by developing a redundant control method with specific properties according to the VDA 6.0 eGAS standard.

[0122] According to the VDA 6.0 eGAS standard, a computer is defined as a structure with three control levels:

[0123] The first two levels are executed on the same microcontroller, called the main microcontroller:

[0124] - The first control level corresponds to a method for controlling the powertrain that executes all the strategies in order to produce the wheel torque requested by the driver using the accelerator pedal and to satisfy various external requirements (driving pleasure, pollution reduction, consumption optimization, etc.).

[0125] - The second control level corresponds to a control method developed independently with respect to the first level in order to guarantee the absence of system failure. The second control level checks whether the operation of the first control level is satisfactory. If an error is detected, there are several possible reactions (resetting the electronic control unit (ECU), limiting the performance, etc.). It must be noted that this control method is simplified with respect to the first level software, since this control method only monitors any failure in the first level that could lead to a potentially safety-related event (i.e.: unwanted acceleration, unwanted deceleration). Other failures are not monitored.

[0126] - The third level is executed on a separate microcontroller and corresponds to monitoring whether the second level is executed satisfactorily via a set of questions and answers. If an error is detected, there are various possible reactions. In the absence of a second microcontroller in the ECU, level 3 can also be executed by another ECU that will diagnose the entire main ECU.

[0127] The steps of the control method will now be defined in more detail.

[0128] In level 1 (SW layer 1) denoted 100 in

[0000] 32, Figure 1 In a first sub-step 10, the position of the accelerator pedal is acquired. In a particular embodiment, speed data required by at least one driving assistance system, in particular a speed controller, are acquired. The accelerator pedal or the driving assistance system is the only interface with which the driver interacts so that it can be known whether the driver wants to accelerate or decelerate the vehicle.

[0129] It should be remembered that, in a vehicle, the accelerator pedal is depressed to establish an acceleration setpoint γ of the vehicle. The acceleration setpoint γ can then be converted into a wheel torque setpoint T 车轮 , or into a power setpoint to be provided to the vehicle. At this stage, the setpoint has not yet been distributed between the different possible energy sources.

[0130] Still during sub-step 10, at least one diagnosis is performed on the acquired values to ensure that the components are operational. The diagnosis is chosen among drift detection, saturation detection, electrical problem detection, etc. by comparing a predetermined value depending on the acquisition to a threshold. If at least one diagnosis shows a fault, a failsafe reconfiguration of the powertrain is proposed in level 1 (SW level 1) so that the powertrain can operate without using the faulty component.

[0131] During sub-step 11, wheel torque setpoints are determined depending on the acquisitions performed so that the powertrain can be controlled to meet acceleration or deceleration requests from the driver.

[0132] In level 2 (SW level 2), denoted 200 in the figure, during sub-step 12, the position of the accelerator pedal is acquired or speed data required by at least one driving assistance system as described above are acquired. Next, at least one diagnosis is performed on the acquired values in order to check that the components are operational. The diagnosis is chosen among drift detection, saturation detection, electrical problem detection, etc. by comparing a predetermined value depending on the acquisition to a threshold. If at least one diagnosis shows a fault, a failsafe reconfiguration of the powertrain is proposed in level 2 (SW level 2) so that the powertrain can operate without using the faulty component.

[0133] Then, during sub-step 13, wheel torque setpoints are determined depending on the acquisitions so that the powertrain can be controlled to meet acceleration or deceleration requests from the driver.

[0134] Level 2 (SW level 2) allows to implement a redundancy in the calculation with respect to level 1 (SW level 1).

[0135] Still in level 2 (SW level 2), a minimum wheel torque difference tolerance and a maximum wheel torque difference tolerance are determined with respect to the risk of excessive acceleration or deceleration. In one particular embodiment, these tolerances depend on the current speed of the vehicle and on whether the driver is accelerating or braking. These tolerances can also depend on other parameters such as the temperature or the grip of the road.

[0136] Then, during sub-step 40, a first check is performed by determining whether the wheel torque setpoints calculated by level 1 (SW level 1) in sub-step 11 are between the wheel torque setpoints calculated by level 2 (SW level 2) in sub-step 13 plus the maximum tolerance and the wheel torque setpoints calculated by level 2 (SW level 2) in sub-step 13 minus the minimum tolerance.

[0137] If yes, the torque setpoints from level 1 are considered safe and the method continues in sub-step 41.

[0138] If not, the method continues in sub-step 42 during which it is determined whether there is a problem. The torque setpoint determined in sub-step 11 by level 1 (SW level 1) is then limited by the maximum tolerance calculated by level 2 (SW level 2) in sub-step 13 to ensure that no safety-related event occurs. This limitation step is performed to improve the availability of the powertrain in order to maintain fail-safe operation of the powertrain rather than immediately interrupting the powertrain torque. This provides good robustness, especially in transient phases (start, acceleration, braking), in the case of slight drifts or calculation discrepancies between the two levels 100, 200.

[0139] If, after a predetermined period of time, it is determined that the wheel torque setpoint calculated in sub-step 11 by level 1 (SW level 1) is still not between the wheel torque setpoint calculated in sub-step 13 by level 2 (SW level 2) plus the maximum tolerance and the wheel torque setpoint calculated in sub-step 13 by level 2 (SW level 2) minus the minimum tolerance, a command to shut down the powertrain is issued, since it is certain that there is a serious fault on the ECU.

[0140] During sub-step 43, level 1 (SW level 1) performs the distribution of the wheel torque setpoint between the drive sources of the powertrain, which is determined previously in sub-step 11 by level 1 (SW level 1) and, if applicable, limited in sub-step 42. This distribution takes into account the requirements relating to energy optimization, driving pleasure, pollution reduction and reliability.

[0141] In other words, the total wheel torque T 车轮 is distributed between the wheel torque contributions to be made by one or more drive sources, in particular the wheel torque T 车轮，发动机 provided by the internal combustion engine and / or the wheel torque T 车轮，电机 provided by the electric machine.

[0142] The distribution depends on various on-board strategies in the vehicle. For example, it can be envisaged that the internal combustion engine is run at the BSFC (brake specific fuel consumption) of the vehicle and that the electric torque to be provided as a complement is calculated so as to correspond to the torque required by the driver. For example, when the pollution reduction device of the internal combustion engine is cold, a high wheel torque setpoint provided by the engine can be chosen in order to increase the heat losses and heat up the device more quickly.

[0143] Regardless of the distribution chosen by the strategy independent of the application, in order to obtain an acceleration corresponding to the expectations of the driver, it is important that the sum of the wheel torques from each drive source is in fact equal to the total torque setpoint or the overall torque setpoint (with a difference within the tolerance).

[0144] Still in sub-step 43, the torque contribution to be provided by said each drive source is determined as a function of the wheel torque contribution to be provided by the drive sources. This calculation is performed taking into account the gear reduction ratio between the drive source and the wheel. In other words, a torque setpoint is determined for each drive source.

[0145] As to the risk of undesirable acceleration or deceleration, it is necessary to check the result of the contribution of all the torque setpoints. It is therefore not advisable to repeat the individual setpoint allocation calculation performed in level 1 (SW level 1) 100 in level 2 (SW level 2) 200.

[0146] In sub-step 41, it is determined in level 2 (SW level 2) whether the sum of the wheel torque setpoints calculated by level 1 is included in the range between the sum of the torque setpoints and the maximum tolerance calculated by level 2 (SW level 2) and the difference between the sum of the torque setpoints and the minimum tolerance calculated by level 2 (SW level 2).

[0147] If yes, the wheel torque setpoints and the torque setpoints of each drive source are considered safe. The method continues in sub-step 44, during which these last torque setpoints are sent to the control systems of the different drive sources.

[0148] If no, the torque setpoints of each drive source are not considered safe and a request to reset the ECU is issued (sub-step 45). If, after the ECU has been reset, it is determined that the sum of the wheel torque setpoints calculated by level 1 is still not included in the range extending between the sum of the torque setpoints and the maximum tolerance calculated by level 2 (SW level 2) and the difference between the sum of the torque setpoints and the minimum tolerance calculated by level 2 (SW level 2), a command is issued to completely shut down the powertrain by interrupting the setpoints at the drive sources and energy sources producing torque (sub-step not shown in the figure). Otherwise, the method returns to sub-step 44. Figure 1

[0149] Based on the individual torque setpoints issued in sub-step 44, each drive source is controlled to produce the required actual torque value. For a powertrain comprising an internal combustion engine and an electric machine, the method comprises sub-step 20 of controlling the actuators of the internal combustion engine and sub-step 21 of controlling the actuators of the electric machine.

[0150] For example, for the internal combustion engine, at least the amount of air and fuel entering the cylinders is adjusted. For the electric machine, the supply voltage and current values of the electric machine are adjusted.

[0151] During sub-step 24, the actual torque provided by the internal combustion engine is estimated. From this, a corresponding value of the actual torque delivered by the engine to the wheels is also derived.

[0152] ​During sub-step 25, the actual torque provided by the electric machine is estimated. From this, the corresponding value of the actual torque provided by the electric machine that is delivered to the wheels is also derived.

[0153] During sub-step 26, by determining whether the actual torque provided by the engine that is delivered to the wheels is not within the range of values extending from the sum of the wheel torque setpoint for the internal combustion engine and the maximum tolerance to the difference between the wheel torque setpoint for the internal combustion engine and the minimum tolerance, an internal combustion engine fault that can lead to exceeding the undesirable acceleration or deceleration tolerance is determined. If so, a command to reset the internal combustion engine is issued. If after a predetermined period of time it is still determined that there is a fault, a command to limit the torque to a predetermined value is issued. If after another predetermined period of time, which can be different from the first predetermined period of time, it is still determined that there is a fault, a command to shut down the internal combustion engine is issued (sub-step not shown in the figure). Figure 1

[0154] During sub-step 27, in a similar manner, by determining whether the actual torque provided by the electric machine that is delivered to the wheels is not within the range of values extending from the sum of the wheel torque setpoint for the electric machine and the maximum tolerance to the difference between the wheel torque setpoint for the electric machine and the minimum tolerance, an electric machine fault that can lead to exceeding the undesirable acceleration or deceleration tolerance is determined. If so, a command to reset the electric machine is issued. If after a predetermined period of time it is still determined that there is a fault, a command to limit the torque to a predetermined value is issued. If after another predetermined period of time, which can be different from the first predetermined period of time, it is still determined that there is a fault, a command to shut down the electric machine is issued (sub-step not shown in the figure). Figure 1

[0155] The power and torque provided by the engine and electric machine respectively, i.e. their actual torque, can be determined by various methods depending on the technology of the source:

[0156] The power is calculated by measuring the current in the electric machine, the torque by measuring the angular speed.

[0157] The combustion torque is calculated by measuring the instantaneous variation of the crankshaft rotation speed in the internal combustion engine, for example as described in FR2681425.

[0158] The torque from the internal combustion engine is calculated by a combustion model based on the energy introduced into the cylinder and its output (amount of fuel injected, combustion phase, richness of the mixture).

[0159] Next, from said actual torque values, the corresponding values of the actual torque delivered to the wheels are derived by taking into account the gear reduction ratio between each source in question and the drive wheels of the vehicle.

[0160] ​​Finally, even if each of the torques actually delivered to the wheels remains within the tolerance individually, the overall value can still exceed the tolerance for the entire driveline, since the tolerance applied to each of the torques actually delivered to the wheels individually is the same as the tolerance applied to the total drive torque of the vehicle. It is then necessary to monitor the overall wheel torque, i.e. the total wheel torque, generated by the driveline in accordance with the total required torque setpoint. To this end, the method continues in substep 30, during which the total torque generated at the wheels is estimated in level 2 (SW layer 2) by adding the values of the torques actually delivered to the wheels provided by each drive source determined in substeps 26, 27 on the basis of the actual torque values.

[0161] During substep 31, it is determined whether the total torque estimated in substep 30 is within a value range extending from the sum of the wheel torque request determined by level 2 (SW layer 2) in substep 13 and the maximum tolerance to the difference between the wheel torque request determined by level 2 (SW layer 2) in substep 13 and the minimum tolerance.

[0162] If not, a command is issued to reset the driveline. If, after a predetermined period of time, the total estimated torque is still not within the value range, a command is issued to shut down the driveline (substep not shown in the figure). Figure 1 If not, a command is issued to reset the driveline. If, after a predetermined period of time, the total estimated torque is still not within the value range, a command is issued to shut down the driveline (substep not shown in the figure).

Claims

1. A method for controlling a powertrain of a motor vehicle, the powertrain comprising at least one drive wheel and two drive power sources, the method comprising the following steps: - determining a maximum wheel torque tolerance and a minimum wheel torque tolerance relative to predetermined rules, - determining a wheel torque setpoint as a function of a torque request from the driver or from at least one driver assistance system, - determining the distribution of the wheel torque setpoint between the driving power sources, - checking whether the sum of the wheel torque setpoints for the driving power sources is within previously determined tolerances with respect to the torque request from the driver, - for each driving power source, checking whether the torque actually delivered to the wheel is within these previously determined tolerances relative to the wheel torque setpoint for that driving power source, - checking whether the sum of the torques from each driving power source actually delivered to the wheel relative to the wheel torque request from the driver is also within these previously determined tolerance ranges, - If at least one of these checks is not verified, a fault is signaled.

2. The control method according to claim 1, wherein: Perform the following steps to determine the wheel torque set point: - determining a first wheel torque request from the driver using a first computing device, - determining a first wheel torque setpoint as a function of the first wheel torque request from the driver and the driving power source of the powertrain using the first calculation means, - determining a second wheel torque request from the driver using a second computing device, - determining a second wheel torque setpoint using the second calculation means as a function of the second wheel torque request from the driver and the driving power source of the powertrain, - checking whether the first wheel torque setpoint and the second wheel torque setpoint are identical, ie whether their difference is within the predetermined tolerances, If yes, the first wheel torque setpoint is considered to be the wheel torque setpoint.

3. The control method according to claim 2, wherein: The actual torque from each driving power source and the torque actually delivered to the wheel from each driving power source are determined using the first computing device.

4. The control method according to claim 3, wherein: The distribution of the wheel torque setpoint among the drive power sources of the powertrain depends on requirements relating to energy optimization, driving pleasure, pollution reduction and vehicle reliability.

5. The control method according to any one of claims 2 to 4, wherein: The distribution of the wheel torque setpoints is determined by the first calculation means.

6. The control method according to any one of claims 2 to 4, wherein: The checking and limiting of the torque set point or actual torque from at least one driving power source is determined by the second calculation means.

7. The control method according to any one of claims 2 to 4, wherein: When a fault signal is issued after the check fails verification, a command is issued to reset the first and second computing devices or each of the at least one driving power source in question, and then the check is performed again; if the check still fails verification, a command is issued to limit the torque set point or actual torque from the at least one driving power source in question.

8. The control method according to any one of claims 1 to 4, wherein: The powertrain is a hybrid powertrain.

9. The control method according to any one of claims 1 to 4, wherein: The at least one driver assistance system includes a speed controller.

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