A protection method for protecting a clutch of a hybrid vehicle from overheating

Abstract

The invention is for protecting a clutch (4) of a hybrid vehicle comprising a heat engine (2) providing a heat engine torque and at least one other power source (10, 18) providing a traction or assistance torque, respectively, a virtual limit of the heat engine being set above which the analysis and control means require the other power source (10, 18) to run at least partly in engine mode. The virtual limit takes into account at least one actual temperature of the clutch and a rotational speed deviation between the crankshaft and the drive shaft, a maximum temperature of the clutch (4) being predetermined, a conversion of the at least one other power source (10, 18) into engine mode being performed at least when a detected temperature of the clutch is higher than the maximum temperature, thereby reducing the torque of the heat engine.

Description

[0001] This invention claims priority to French application 1909565, filed on August 30, 2019, the contents of which (text, drawings and claims) are incorporated herein by reference. Technical Field

[0002] The present invention relates to a protection method for protecting the clutch of a hybrid vehicle, the hybrid vehicle comprising: a thermal engine; at least one other power source including an energy storage device; and a clutch that connects at least the thermal engine to at least one wheel drive axle of the vehicle, the clutch being protected from overheating. Background Technology

[0003] As is known in the prior art, a hybrid vehicle includes: a heat engine; at least one other power source, said at least one other power source including an energy storage device; and a clutch that connects the heat engine to at least one wheel drive axle of the vehicle.

[0004] In this configuration, one or more other power sources have two actuation modes: an engine mode, in which these power sources provide energy to send traction or auxiliary torque to the thermal engine; and a generator mode, in which these power sources store the energy provided by the thermal engine via an energy storage device.

[0005] A heat engine and one or more other power sources provide heat engine torque and traction or auxiliary torque, respectively, which are used in response to the instantaneous power requirements of the vehicle driver.

[0006] It also includes analysis and control components suitable for controlling the thermal engine and one or more other power sources. Virtual limits for the thermal engine are set by the analysis components. Above these virtual limits, the analysis and control components require one or more other power sources to operate at least partially in engine mode.

[0007] The instantaneous power requirements of the driver are prioritized so that, if the traction or auxiliary torque is required or desired in response to that intention, the analysis and control components cause the one or more other power sources to at least partially switch to engine mode at the moment in response to the instantaneous power requirements.

[0008] The one or more power sources that can operate as generators can be placed between the clutch and the wheels of the hybrid vehicle or directly on the wheels.

[0009] In some applications, a clutch is required. This clutch generates heat when it slips, and the energy dissipated in the slipping clutch is equal to the integral of the power dissipated between the crankshaft and the wheel drive shaft. This dissipated power can be calculated by multiplying the speed difference between the upstream and downstream sides of the clutch by the torque that can be transmitted by the clutch.

[0010] On steep slopes or when the vehicle is heavy (e.g., towing a station wagon), or when the driver demands high torque, the clutch generates a lot of heat while its cooling system is relatively small.

[0011] Therefore, the problem upon which this invention is based is to avoid the clutch from overheating during vehicle operation in a hybrid vehicle that includes at least one non-thermal power source and a thermal engine connected to at least one drive shaft via a clutch. Summary of the Invention

[0012] Therefore, the present invention relates to a protection method for protecting the clutch of a hybrid vehicle, the hybrid vehicle comprising: a thermal engine; at least one other power source including an energy storage device; a clutch connecting at least the thermal engine to at least one wheel drive axle of the vehicle, the at least one other power source having two actuation modes, including an engine mode and a generator mode, wherein in the engine mode, the at least one other power source provides energy to send traction or auxiliary torque to the thermal engine, and in the generator mode, the at least one other power source stores the energy provided by the thermal engine via the energy storage device, the thermal engine and the at least one other power source respectively providing thermal engine torque and traction or auxiliary torque, the thermal engine torque and the traction or auxiliary torque being used in response to instantaneous power demand from the driver; and an analysis and control component adapted to control the thermal engine and the at least one other power source. The power source, the virtual limit of the thermal engine, is set by the analysis unit. Above this limit, the analysis and control unit requires the at least one other power source to operate at least partially in engine mode. The instantaneous power demand from the driver's perspective is prioritized, so that if the traction or auxiliary torque is required or desired in response to the intention, the analysis and control unit causes the at least one other power source to at least partially switch to engine mode at the moment in response to the instantaneous power demand. The virtual limit takes into account at least one actual temperature of the clutch and the speed deviation associated with the crankshaft of the thermal engine and the at least one drive shaft. The maximum temperature of the clutch is predetermined. At least when the detected temperature of the clutch is higher than the maximum temperature of the clutch and there is a speed deviation between the upstream and downstream of the clutch, the at least one other power source is at least partially switched to engine mode, thereby reducing the torque transmitted by the clutch and therefore the torque provided by the thermal engine.

[0013] The basic principle of this invention lies in reducing the torque transmitted by the clutch by stimulating at least one other power source besides the thermal engine. Therefore, it is possible to control power dissipation because the torque of this other power source is calculated such that the power to be transmitted to the clutch does not exceed a value equal to the heat dissipation value of the clutch. "At least when the detected temperature of the clutch is above the maximum temperature" means that switching above this maximum temperature is necessary. Conversely, in an alternative embodiment, partial switching can be performed below this predetermined maximum temperature, as will be described below.

[0014] As an idea, and particularly depending on the type of clutch, the maximum temperature can be 180°C or above. The dissipable power thus needs to be kept below a specific value, for example, below 10 kWatt, which is achieved by at least partially switching the at least one other power source into engine mode.

[0015] When the temperature of the clutch exceeds a predetermined maximum temperature, the limiting inducement of the thermal engine is executed to distribute torque at the distribution management level between the engine and one or more other power sources.

[0016] The torque setpoint is applied by the thermal engine up to a virtual limit for the thermal engine. Above this virtual limit, one or more other power sources are used to supplement the thermal engine operating at reduced power or to supplement the thermal engine that has been shut down.

[0017] According to the invention, the virtual limit of the engine is a function of a standard depending on the clutch temperature to protect the clutch. This virtual limit for clutch protection depends on the clutch temperature and the speed deviation between the drive shaft and the crankshaft of the thermal engine. The smaller the speed increment (delta), the greater the torque that can be transmitted before using the one or more power sources, because the energy dissipation is not greater. This mechanism allows for a specific maximum power dissipation in the clutch. When the clutch temperature approaches its maximum temperature, the maximum allowed power will approach the clutch's heat dissipation power.

[0018] Under extreme temperature conditions and at the moment when the speed increment of the clutch is completely eliminated, the torque transmitted by the clutch can be reduced until it is eliminated.

[0019] Therefore, in the context of this invention, it is possible to keep the thermal engine running but with reduced power.

[0020] Advantageously, the at least one other power source is gradually converted to engine mode, at least partially, based on a predetermined minimum temperature that is 50% below the maximum temperature.

[0021] Using a maximum temperature of approximately 180°C as a non-limiting example, as described above, at this maximum temperature of 180°C, the power dissipable may need to be kept below 10 kWatt to avoid overheating of the clutch.

[0022] Conversely, in this configuration, the dissipable power at 150°C can rise up to 40 to 50 kWatt before a gradual transition. Below 100°C, the dissipable power cannot be adjusted by transition.

[0023] Based on the maximum dissipable power value for temperatures between 100°C and 180°C or even higher, the torque is determined according to the rotational speed so as not to exceed the maximum dissipable power predetermined for a given temperature.

[0024] This allows for the prediction of excessive heat generation in the clutch and the prevention of reaching or reaching the maximum temperature too quickly.

[0025] Advantageously, before at least partially converting the at least one other power source to engine mode, the analysis and control unit first requires the thermal engine not to supply power to the energy storage device when the detected temperature of the clutch is higher than the minimum temperature of the clutch.

[0026] This temporary measure reduces overheating of the clutch by not requiring the thermal engine to power the energy storage device. If this is insufficient, one or more other power sources are started to compensate for the reduction in torque generated by the thermal engine, or even to compensate for the shutdown of the thermal engine.

[0027] Advantageously, the virtual limit also takes into account two charging thresholds of the energy storage device, which are predefined in the analysis and control unit, one of which is defined as a priority charging threshold and the other as a releasable charging threshold, the priority charging threshold being lower than the releasable charging threshold. When the analysis and control unit determines that the charging level of the energy storage device is lower than the priority charging threshold and the detected temperature of the clutch is higher than the minimum temperature, the analysis and control unit reduces or eliminates at least a partial conversion of the at least one other power source and keeps the thermal engine running.

[0028] This prevents the energy storage device from being fully discharged (and thus undercharged). An intermediate solution could be to operate the thermal engine at a reduced power level so as not to consume too much of the one or more other power sources.

[0029] Advantageously, the at least one other power source includes at least two other power sources respectively connected to the drive shaft, wherein a first power source of the at least two other power sources is switched preferentially over the at least one second power source.

[0030] Advantageously, after the first power source is preferentially switched, the at least one second power source is also switched while the detected temperature remains above the maximum temperature of the clutch.

[0031] The present invention also relates to an assembly of a thermal engine, at least one other power source, a clutch, and analysis and control components, wherein the at least one other power source includes an energy storage device, and the clutch connects the thermal engine to at least one wheel drive axle of the vehicle, characterized in that the assembly implements a protection method for protecting the clutch.

[0032] Advantageously, the at least one other power source is an electric motor, and the energy storage device is at least one battery.

[0033] The present invention relates to a hybrid electric vehicle, characterized in that the hybrid electric vehicle includes such a component.

[0034] This invention can protect the clutch by controlling its temperature, control electrical energy, optimize the cooling system, and has little or no impact on the performance and control of the power system.

[0035] For vehicles with four powered wheels, this has no effect on the distribution between the front and rear drive axles.

[0036] Advantageously, the motor vehicle is a vehicle with four powered wheels and a front drive shaft and a rear drive shaft, the front drive shaft being connected to a front motor and the rear drive shaft being connected to a rear motor, the analysis and control unit having a conversion component for the front motor, the conversion component for the front motor being preferred over the conversion component for the rear motor. Attached Figure Description

[0037] Other features, objects, and advantages of the invention will become clearer from the following detailed description and the accompanying drawings, which are given as non-limiting examples, in which:

[0038] - Figure 1 This is a schematic diagram of a hybrid vehicle that implements a protection method according to the invention for protecting the clutch of a thermal engine from overheating.

[0039] - Figure 2 Flowcharts illustrating protection methods conforming to embodiments of the present invention are shown for cases involving a thermal clutch with both fully and insufficiently charged energy storage devices.

[0040] - Figure 3 Torque curves provided by the thermal engine and two motors at the front and rear are shown, along with virtual limitations when implementing and not implementing the method according to the invention.

[0041] - Figure 4The illustrations show three sets of power curves for a motor vehicle with four powered wheels, provided by a thermal engine and at least one non-thermal source, with and without implementing the method according to the invention. Detailed Implementation

[0042] All figures will be used in combination, and reference may be made to the figure references in one of the other figures during the description of one figure.

[0043] refer to Figure 1 The present invention relates to a protection method for protecting a clutch 4 of a hybrid vehicle, the hybrid vehicle comprising: a thermal engine 2; at least one non-thermal power source 10, 18, referred to below as other power sources, the at least one non-thermal power source including an energy storage device 12; and a clutch 4, the clutch connecting at least the thermal engine 2 to at least one wheel drive axle 8, 26 of the vehicle.

[0044] More specifically, the present invention relates to an architecture in which the disengagement clutch is positioned between one or more other power sources 10, 18 and the heat engine 2. If the gearbox is closed, the one or more power sources 10, 18 can be directly connected to the wheels 8, 26.

[0045] If in Figure 1 As explicitly stated in the description, one or more power sources 10, 18 may advantageously be electric motors, but may be replaced, for example, by pneumatic or hydraulic technology.

[0046] Clutch 4 can be operated in response to the excitation of this strategy. The transmission 6 is provided with different gear ratios and is connected to the front drive wheels 8 of the vehicle.

[0047] The exhaust pipe 50 is provided with components suitable for treating exhaust gases (especially unburned gases from the combustion chamber of the thermal engine 2), such as particulate filters and / or oxidation catalysts.

[0048] The input shaft of the transmission 6 receives the motion of the clutch 4. The input shaft includes a front traction motor 10, which serves as another power source and is powered by a second low-voltage traction battery 12, which acts as an energy storage device. In this way, the front motor 10 can transmit torque to the drive wheels 8 using different gear ratios provided by the transmission 6 without passing through the clutch 4.

[0049] The on-board charger 14 can be connected to the power distribution network via an external plug 16 to charge the second traction battery 12 when the vehicle is stationary. The second traction battery 12 has a low voltage, which may be, for example, 220 or 300 volts.

[0050] The second traction battery 12 also supplies power to the rear traction motor 18, which is connected in sequence to the rear differential 24 via the reducer 20 and the differential lock system 22, which distributes motion to the rear wheels 26 of the vehicle.

[0051] Alternator 30 (also referred to as AC starter) is permanently connected to thermal engine 2 via belt 32 and supplies power to onboard network, referred to as auxiliary circuit, which includes battery 34 for very low voltage auxiliary circuit.

[0052] As a supplement, the battery 34 of the ultra-low voltage auxiliary circuit (also referred to as the first battery relative to the second traction battery 12) can be charged by a DC / DC converter 36, which receives power from the second traction battery 12 or power from the front motor 10 or the rear motor 18 (if the energy level of the second traction battery 12 is insufficient).

[0053] During the release of the vehicle's brake or accelerator pedal, motors 10 and 18 operate as generators and send braking torque to charge the second traction battery 12 and recover energy.

[0054] Analysis and control components (in) Figure 1 (Not shown) The operation of this powertrain is controlled to respond to the driver's demands, while optimizing energy consumption and pollutant emissions according to conventional strategies.

[0055] In this example, the second traction battery 12 constitutes an energy storage device according to the invention, while the assembly formed by the front traction motor 10 and the rear traction motor 18 constitutes another power source according to the invention.

[0056] Typically, one or more other power sources 10, 18 (i.e., for example) Figure 1 The motor in the motor has two actuation modes.

[0057] The first mode is engine mode, in which these power sources provide energy to send traction or auxiliary torque to the heat engine 2.

[0058] The second mode is the generator mode, in which these power sources store the energy provided by the thermal engine 2 via the energy storage device 12.

[0059] The thermal engine 2 and one or more other power sources 10, 18 provide thermal engine torque and traction or auxiliary torque, respectively, which are used in response to the instantaneous power requirements of the driver.

[0060] As described above, the analysis and control unit is adapted to control the thermal engine 2 and one or more other power sources 10, 18. The virtual limits of the thermal engine 2 are set by the analysis unit.

[0061] Above this virtual constraint, the analysis and control unit requires one or more other power sources 10, 18 to operate at least partially in engine mode, prioritizing the driver's instantaneous power demand, such that if the traction or auxiliary torque is required or desired in response to the driver's intention (meaning torque in Newton-meters (Nm), then at the moment in response to the instantaneous power demand, the analysis and control unit causes one or more other power sources 10, 18 to switch at least partially to engine mode.

[0062] "At least part" means that in the case of multiple other power sources 10, 18, only a portion of these other power sources can be converted.

[0063] According to the present invention, in order to protect the clutch 4 from overheating, the virtual limit takes into account at least the actual temperature of the clutch 4 and the speed deviation between the crankshaft of the thermal engine and the at least one drive shaft.

[0064] Therefore, the maximum temperature of clutch 4 is predetermined so as not to irreversibly damage the clutch.

[0065] When the detected temperature of clutch 4 is higher than the predetermined maximum temperature of clutch 4 and there is a speed deviation between the upstream and downstream of the clutch (the heat source of the clutch), the operation of at least partially converting one or more other power sources 10, 18 into engine mode is performed. Therefore, the torque transmitted by the clutch and thus the torque provided by the thermal engine 2 is reduced or even eliminated.

[0066] This conversion is more suitable for the low speed of the engine. Conversely, it is also possible to continue using the hot engine 2 without increasing the temperature of the clutch 4 when the clutch is engaged, even at high speeds and with a hot clutch.

[0067] Therefore, one or more other power sources 10 and 18 are used to limit overheating of the clutch 4. The heat engine 2 is thus less excited, which reduces the energy dissipation in the clutch 4.

[0068] Therefore, the lower the speed increment, the higher the transmittable torque before using one or more other electrical sources. This mechanism allows for a specific maximum power dissipation in clutch 4. When the temperature of the clutch approaches its maximum temperature, the maximum allowable power will be close to and will not exceed the heat dissipation power of clutch 4 so as not to increase the temperature of the clutch.

[0069] The torque transmitted by clutch 2 can be reduced until it is eliminated, at which point the thermal engine 2 is stopped.

[0070] This is possible when the driver's torque requirement is reduced or when the energy storage 12 is fully charged.

[0071] During its operation, the heat engine 2 also supplies power to the energy storage device 12 via an alternator or alternator, which can also cause the clutch 4 to heat up. In order to predict or prevent the maximum heat generation of the clutch 4, it is possible to implement at least partially and gradually switch one or more other power sources 10, 18 to engine mode based on a predetermined minimum temperature that is 50% below the maximum temperature.

[0072] Before at least partially converting one or more other power sources 10, 18 to engine mode, the analysis and control unit may first require the thermal engine not to supply power to the energy storage device 12 when the detected temperature of the clutch 4 is higher than the minimum temperature of the clutch 4.

[0073] The heat engine 2 is thus less excited and generates less heat, as is the clutch 4.

[0074] Subsequently, even when the detected temperature becomes higher than the maximum temperature of the clutch 4, even when no power is supplied to the energy storage 12, the conversion of one or more other power sources 12, 18 is performed.

[0075] Conversely, as a precaution, when the thermal gradient of the clutch is large, causing the maximum temperature of the clutch to be reached predictably too quickly, the at least partial switching can be performed before that maximum temperature is reached. An excessively large thermal gradient can be determined, to the extent possible by those skilled in the art, particularly by taking into account the type of clutch.

[0076] The virtual limit may also take into account two charging thresholds for the energy storage 12, which are predefined in the analysis and control unit.

[0077] The first threshold may be defined as a priority charging threshold, and the second threshold may be defined as a removable charging threshold. The priority charging threshold is lower than the removable charging threshold.

[0078] When the analysis and control unit determines that the charging level of the energy storage 12 is below the priority charging threshold and the detection temperature of the clutch 4 is above the minimum temperature, the analysis and control unit may reduce or eliminate at least a partial conversion of the at least one other power source 10, 18 and keep the heat engine 2 running.

[0079] Figure 2A flowchart of the protection method according to the present invention is shown. Reference numeral C denotes a thermal clutch. Therefore, it is possible to either not execute any target charging power inducement when the energy storage is insufficiently charged (reference numeral A), or execute the target charging power inducement when the energy storage is sufficiently charged (reference numeral B).

[0080] In scenario B, an attempt is made to delay the priority power to a later time to avoid further heating of the clutch within the acceptable charging range of the energy storage device due to the inducement of the priority power.

[0081] If, despite this, priority power is required, the powertrain will perform exactly the same regardless of whether the clutch is hot or not, and protecting the clutch from overheating will no longer be prioritized.

[0082] When there are at least two other power sources respectively connected to the drive shaft, it is possible that only the first power source 10 of the at least two other power sources 10, 18 is switched over the at least one second power source 18.

[0083] However, after the first power source 10 is preferentially switched, the second power source 18 is also switched while the detected temperature remains above the maximum temperature of the clutch 4. This applies continuously to multiple other power sources present in the hybrid vehicle.

[0084] Again, the main reference Figure 1 The invention also relates to an assembly of a thermal engine 2, at least one other power source 10, 18, a clutch 4, and an analysis and control unit, wherein the at least one other power source includes an energy storage device 12, and the clutch connects the thermal engine 2 to at least one wheel drive axle of the vehicle. The assembly thus implemented essentially implements the protection method for protecting the clutch 4 as described above through a computing unit present in the analysis and control unit, to determine the virtual limit based on the temperature of the clutch measured or estimated by a temperature sensor and the rotational speed deviation between the crankshaft and one or more wheel axles measured by a rotation sensor.

[0085] One or more other power sources 10, 18 may be motors, and energy storage device 12 may be at least one battery.

[0086] The present invention relates to a hybrid electric vehicle, the hybrid electric vehicle comprising the components described above.

[0087] The motor vehicle may be a vehicle with four powered wheels, the vehicle having a front drive shaft and a rear drive shaft, the front drive shaft being connected to a front motor 10, and the rear drive shaft being connected to a rear motor 18.

[0088] Each other power source 10, 18 may be located between the clutch 4 of the motor vehicle and the wheel, or directly on the wheel.

[0089] The analysis and control components may have switching components for switching the front motor 10, which are preferred over switching components for switching the rear motor 18. However, this is not limiting.

[0090] The virtual limit used to protect clutch 4 depends on the temperature of the clutch and the speed difference between the main shaft and the crankshaft.

[0091] Although the rear motor 18 often has better efficiency, the rejet is preferably implemented on the front motor 10 here.

[0092] Since the torque distribution will depend on the speed deviation, and this torque distribution will be very dynamic, it is preferred to use the front motor rather than the rear motor so as not to affect the torque compensation on the front and rear shafts.

[0093] If the front motor 10 is unable to provide adequate assistance for separation, the rear motor 18 will take over. Advantageously, due to the rapid dynamics of the speed increment, modifications to the torque distribution between the thermal engine 2 and one or more other power sources have no effect on the switching law.

[0094] The energy storage device 12 can be a traction battery. When the traction battery is being preferentially charged, the unloading strategy of the thermal engine (either by disconnecting from the AC starter or by reducing the torque supply power) cannot be applied to prevent further consumption of the traction battery.

[0095] However, it is possible to temporarily change the preferred charging threshold by reducing it, so as to be able to prefer the use of one or more other power sources.

[0096] The front motor is used to compensate for the thermal clutch 4, although the rear motor is preferred because this avoids affecting torque distribution.

[0097] Figure 3 The torque curves C for two series are shown in Newton-meters (Nm).

[0098] For the first series of curves in the upper part, curve CTAV is the front axle torque curve, and curve CTAR is the rear axle torque curve. It can be seen that the upper horizontal dashed line Ls (without implementing a protection method to prevent clutch overheating) characterizing the virtual limit is higher than the lower horizontal dashed line L (with the method implemented) characterizing the virtual limit.

[0099] For the second series of curves in the lower part, curve consMth is the torque setpoint curve transmitted by the clutch, curve cons AR is the torque setpoint curve provided by the rear motor, and curve cons AV is the torque setpoint curve provided by the front motor.

[0100] The virtual limit Ls is a virtual limit without the implementation of a protection method to prevent the clutch from overheating, and is higher than the virtual limit L with the implementation of such a method. Reference numerals AV and AR represent the virtual limits of the front motor and the rear motor, respectively.

[0101] For a motor vehicle with a thermal engine and at least one non-thermal power source (the vehicle having four powered wheels), Figure 4 Three sets of power curves in kWatt (kW) are shown as a function of time t in seconds (s).

[0102] The first set of curves shows the original priority power curve Ppb, the priority power curve PpT as a function of the temperature of the clutch, and the minimum priority power curve Ppmi for protecting the charge contained in the energy storage.

[0103] The second series of curves, which is below the first series, shows the minimum priority power curve, the original priority power curve, and the priority power curve as a function of the temperature of the clutch for protecting the charge contained in the energy storage. The second series of curves is similar to the first series of curves, but these three curves are not marked.

[0104] In addition, the second series of curves shows the comprehensive priority power curve Psp used to protect the clutch.

[0105] The third series of curves, located below the second series, shows the minimum priority power curve, the original priority power curve, and the priority power curve as a function of the temperature of the clutch for protecting the charge contained in the energy storage. This third series of curves is similar to the first and second series of curves, but these three curves are not labeled.

[0106] In addition, the third series of curves shows the coordinated final priority power curve Ppfc.

[0107] In the ellipse O1 of the first series of curves, the clutch heats up. Limiting or even eliminating the power that the electrical system, including the energy storage device, wants to extract from the heat engine is implemented to prevent further slippage of the clutch.

[0108] In the ellipse O2 of the second series of curves, the clutch heats up, but the charging level of the energy storage becomes below the priority charging threshold. The priority power is disabled to ensure minimum charging, so that a charging level above the priority charging threshold is achieved.

[0109] In ellipse O3 of the third series of curves, the clutch heats up. If the priority charging threshold is exceeded, the final power is ultimately reduced. This reduction preferably occurs at low speeds because it is possible to continue charging the energy storage without increasing the clutch temperature at high speeds, given the hot clutch when engaged.

[0110] The present invention is not limited to the embodiments described and shown by way of example only.

Claims

1. A method for protecting a clutch (4) of a hybrid vehicle, the hybrid vehicle comprising: Thermal engine (2); At least one other power source, the at least one other power source including an energy storage device (12); a clutch (4) that connects at least the thermal engine to at least one wheel drive axle of the vehicle, the at least one other power source having two actuation modes, including an engine mode and a generator mode, in which the at least one other power source provides energy to send traction or auxiliary torque to the thermal engine (2), and in the generator mode, the at least one other power source stores the energy provided by the thermal engine (2) via the energy storage device (12), the thermal engine (2) and the at least one other power source respectively providing thermal engine torque and traction or auxiliary torque, the thermal engine torque and the traction or auxiliary torque being used in response to instantaneous power requirements from the driver; an analysis and control unit adapted to control the thermal engine (2) and the at least one other power source, the virtual limit of the thermal engine being set by the analysis and control unit. The analysis and control unit, above the virtual constraint, requires the at least one other power source to operate at least partially in engine mode, with the driver's instantaneous power demand taking precedence, such that if the traction or auxiliary torque is required or desired in response to the driver's will, at the moment in response to the instantaneous power demand, the analysis and control unit causes the at least one other power source to be at least partially switched to engine mode. The virtual constraint takes into account at least one actual temperature of the clutch (4) and the speed deviation between the crankshaft of the thermal engine and the at least one drive shaft, the maximum temperature of the clutch (4) being predetermined. At least when the detected temperature of the clutch (4) is higher than the maximum temperature of the clutch (4) and there is a speed deviation between the upstream and downstream of the clutch (4), the at least one other power source is switched at least partially to engine mode, thereby reducing the torque transmitted by the clutch (4) and therefore the torque provided by the thermal engine (2).

2. The protection method according to claim 1, wherein, Based on a predetermined minimum temperature that is 50% below the maximum temperature, the at least one other power source is gradually converted to engine mode, at least partially.

3. The protection method according to claim 2, wherein, Before at least partially converting the at least one other power source to engine mode, when the detected temperature of the clutch (4) is higher than the minimum temperature of the clutch (4), the analysis and control unit first requests that the thermal engine not supply power to the energy storage device (12).

4. The protection method according to claim 2 or 3, wherein, The virtual limit also takes into account two charging thresholds of the energy storage device (12), which are predefined in the analysis and control unit, one of which is defined as a priority charging threshold and the other as a detachable charging threshold, the priority charging threshold being lower than the detachable charging threshold. When the analysis and control unit determines that the charging level of the energy storage device (12) is lower than the priority charging threshold and the detected temperature of the clutch (4) is higher than the minimum temperature, the analysis and control unit reduces or eliminates at least a partial conversion of the at least one other power source and keeps the thermal engine (2) running.

5. The protection method according to any one of claims 1 to 3, wherein, The at least one other power source includes at least two other power sources respectively connected to the drive shaft, wherein a first power source of the at least two other power sources is converted in priority over the at least one second power source.

6. The protection method according to claim 5, wherein, After the first power source is preferentially switched, when the detected temperature remains above the maximum temperature of the clutch (4), the at least one second power source is also switched.

7. An assembly comprising a thermal engine (2), at least one other power source, a clutch (4), and analysis and control components, said at least one other power source including an energy storage device (12), said clutch connecting at least the thermal engine (2) to at least one wheel drive axle of the vehicle, characterized in that, The component implements a protection method for protecting the clutch (4) of a hybrid vehicle according to any one of claims 1 to 6.

8. The component according to claim 7, wherein, The at least one other power source is an electric motor, and the energy storage device (12) is at least one battery.

9. A hybrid electric vehicle, characterized in that, The hybrid electric vehicle includes the components as described in claim 7 or 8.

10. The hybrid electric vehicle according to claim 9, wherein the hybrid electric vehicle is a vehicle having four powered wheels and having a front drive shaft and a rear drive shaft, the front drive shaft being connected to a front motor (10) and the rear drive shaft being connected to a rear motor (18), the analysis and control unit having a conversion component of the front motor (10), the conversion component of the front motor being preferred over the conversion component of the rear motor (18).

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