Method for protecting a hybrid vehicle's clutch from overheating by stopping charging

Abstract

A method for protecting a clutch of a hybrid vehicle from overheating by charging stop, the method protecting a clutch (4) of a hybrid vehicle comprising a heat engine (2) and at least one other power source (10, 18) providing heat engine torque and traction or auxiliary torque, respectively. The other power source (10, 18) also has a generator mode for storing energy provided by the heat engine (2) via an energy storage device (12). An analysis and control component controls the heat engine (2) and the other power source (10, 18) and determines the charging level. When the temperature (4) of the clutch exceeds a first temperature threshold and the speed difference between upstream and downstream of the clutch exceeds a threshold between 0 and 1000 rpm, the analysis and control component requests that the heat engine not supply power to the energy storage device (12) while keeping the other power source (10, 18) inactive in engine mode.

Description

[0001] The present application claims priority from French application No. 1909567, filed on August 30, 2019, the content (text, drawings and claims) of which is incorporated herein by reference. Technical Field

[0002] The invention relates to a method for protecting a clutch of a hybrid vehicle comprising a heat engine from overheating by managing the charging of an energy storage device of at least one power source other than the heat engine by the heat engine. The clutch couples at least the heat engine to at least one wheel drive shaft of the vehicle. Background Art

[0003] As is known in the prior art, hybrid vehicles comprise a heat engine, at least one other power source including an energy storage device, and a clutch coupling at least the heat engine to at least one wheel drive shaft of the vehicle.

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

[0005] The heat engine and one or more other power sources provide heat engine torque and tractive or assist torque, respectively, which are used to respond to transient power demands on the part of the vehicle operator.

[0006] An analysis and control unit is also provided for controlling the heat engine and one or more other power sources. A virtual limit of the heat engine is set by the analysis unit. Above this virtual limit, the analysis and control unit requires the one or more other power sources to operate at least partially in engine mode.

[0007] The instantaneous power request on the part of the driver is prioritized so that if traction or assist torque is required or desired in response to this desire, the analysis and control component causes the one or more other power sources to be at least partially converted into engine mode at the moment of response to the instantaneous power request.

[0008] The one or more power sources operable as generators may be placed between the clutch and the wheels of the hybrid vehicle or directly at the wheels.

[0009] In some applications, a clutch is required. This clutch heats up when it slips. 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 upstream and downstream of the clutch by the torque that can be transmitted by the clutch.

[0010] On steep slopes or when the vehicle is heavy (for example, towing a station wagon), or when the vehicle driver demands high torque, the clutch heats up very quickly and the cooling system for it is small.

[0011] Furthermore, in the operating mode in which the one or more other power sources act as generators, the heat engine is used to charge the energy storage device, which increases the operating temperature of the clutch.

[0012] The invention is therefore based on the problem of avoiding heating of the clutch during driving use of a hybrid vehicle comprising 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

[0013] To this end, the present invention relates to a protection method for protecting a clutch of a hybrid vehicle, the hybrid vehicle comprising: a heat engine; at least one other power source, the at least one other power source comprising an energy storage device; a clutch, the clutch coupling at least the heat engine with at least one wheel drive shaft of the vehicle, the at least one other power source having two actuation modes, including an engine mode and a generator mode, in which, in the engine mode, the at least one other power source provides energy in order to send traction or auxiliary torque to the heat engine, in the generator mode, the at least one other power source supplies power to an electrical circuit in order to store energy provided by the heat engine via the energy storage device, the heat engine and the at least one other power source. one other power source provides a heat engine torque and a traction or assistance torque, respectively, which are used to respond to a transient power demand from the driver; an analysis and control component, which is suitable for controlling the heat engine and the at least one other power source and determining the charge level of the energy storage, characterized in that when the measured or estimated temperature of the clutch exceeds a predetermined first temperature threshold and the speed deviation between the upstream and downstream of the clutch exceeds a calibratable predetermined threshold between 0 and 1000 rpm, the analysis and control component requires the heat engine to not supply power to the energy storage, while keeping the at least one other power source inactive in engine mode.

[0014] The speed deviation threshold depends on the temperature. The higher the clutch temperature, the lower the speed threshold, effectively equal to 0. If the clutch temperature is below the temperature threshold, the clutch is not heating, and the speed deviation threshold is not considered. The maximum dissipable power value is given below; the greater the maximum dissipable power, the lower the clutch temperature.

[0015] The supply of power to the energy storage device by the heat engine causes the clutch temperature to increase. At a first temperature threshold (which is advantageously lower than the maximum temperature to which the clutch can withstand), the invention proposes to stop supplying power to the energy circuit by the heat engine in order to at least prevent the clutch temperature from increasing, or even to reduce it.

[0016] Advantageously, the analysis and control component also takes into account two predefined charging thresholds of the energy storage, one of which is defined as a priority charging threshold and the other as a unloadable charging threshold, the priority charging threshold being lower than the unloadable charging threshold. When the analysis and control component determines that the charge level of the energy storage is lower than the priority charging threshold and the detected temperature of the clutch is higher than the predetermined first temperature threshold, the analysis and control component keeps the heat engine running to power the energy storage.

[0017] This makes it possible not to completely discharge the energy storage (and thus undercharge it). For example, the priority charge threshold can be set to 13% of the unloadable charge threshold, and it is possible to reduce the priority charge threshold to 11% in the case of high temperatures and large speed deltas, as described above, and to facilitate the use of one or more non-thermal power sources.

[0018] Advantageously, when the measured or estimated temperature of the clutch exceeds a predetermined second temperature threshold, the analysis and control component performs an at least partial conversion of the at least one other power source into engine mode, thereby reducing the torque transmitted by the clutch and therefore the torque provided by the heat engine.

[0019] The present invention initially proposed to reduce overheating of the clutch by not requiring the heat engine to power the energy storage.This measure may prove to be insufficient and the clutch temperature may continue to rise.

[0020] If this is the case, one or more other power sources are started and compensate for the reduction in torque production of the heat engine, or even for its stopping, which will result in a drop in the temperature of the clutch.

[0021] Taking as a non-limiting example a maximum temperature that a clutch can withstand above 180° C., at this 180° C. maximum temperature, the dissipable power may need to be kept below 10 kWatt to avoid heating of the clutch.

[0022] In contrast, in this configuration, the dissipable power at 150° C. can rise to 40 to 50 kWatt before gradually switching. Below 100° C., the dissipable power cannot be regulated by switching and is only controlled if necessary by pausing the heat engine to charge the energy storage.

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

[0024] This makes it possible to anticipate excessive heating of the clutch and to avoid reaching the maximum temperature or reaching it too quickly.

[0025] The basic principle of this alternative mode of the invention is to reduce the torque transmitted by the clutch by activating at least one other power source than the heat engine. It is thus possible to manage the dissipated power, since the torque of this other power source is calculated so that the power transmitted to the clutch does not exceed a value equal to the heat dissipation value of the clutch.

[0026] The partial shifting may be performed according to a second threshold value, which may advantageously be lower than the maximum temperature to which the clutch can withstand, in order to protect the clutch.

[0027] As a concept, depending in particular on the type of clutch, the second temperature threshold may be 180° C. or above, while being below the maximum temperature to which the clutch can withstand. The power dissipation may be kept below a certain value, for example below 10 kWatt, by at least partially switching the at least one other power source to engine mode.

[0028] When the temperature of the clutch exceeds a second temperature threshold, a limiting inducement of the heat engine is executed for distributing the torque at a distribution management level between the engine and one or more other power sources.

[0029] The torque setpoint is implemented by the heat engine up to a virtual limit of the heat engine. Above this virtual limit, one or more other power sources are used to either supplement the heat engine working with reduced power or to supplement the stopped heat engine.

[0030] According to the invention, the virtual limit of the engine is a function of a criterion depending on the clutch temperature for protecting the clutch. This virtual limit for protecting the clutch depends on the clutch temperature and the speed deviation between the drive shaft and the crankshaft of the heat engine.

[0031] The smaller the speed increment, the greater the torque that can be transmitted before the one or more power sources are used, because the dissipated energy is not greater. This mechanism allows a certain maximum power dissipation in the clutch. When the temperature of the clutch approaches a second temperature threshold (and therefore the maximum temperature of the clutch), the maximum power allowed will be close to the thermal dissipation power of the clutch.

[0032] In the event of extreme temperatures and at the point where the clutch speed increase is completely eliminated, the torque transmitted by the clutch may be reduced until it is eliminated.

[0033] In the context of the present invention, it is therefore possible to keep the heat engine in operation but with reduced power.

[0034] Advantageously, the first temperature threshold is 100° C. and the second temperature threshold is 180° C., with a range of + / - 20% around each threshold. As a safety measure, the second threshold may be lower than the maximum temperature to which the clutch is subjected, which maximum temperature is predetermined according to the type of clutch.

[0035] Advantageously, the at least partial switching of said at least one other power source into engine mode is performed gradually.

[0036] Advantageously, the at least one other power source includes at least two other power sources respectively connected to the drive shaft, a first power source among the at least two other power sources is converted in priority to the at least one second power source, and, after the priority conversion of the first power source, when the detected temperature remains higher than the second temperature threshold, the at least one second power source is also converted.

[0037] The invention also relates to an assembly of a thermal engine, at least one other power source including an energy storage device, a clutch and an analysis and control component, wherein the at least one other power source connects the thermal engine at least to at least one wheel drive shaft of the vehicle, characterized in that the assembly implements such a protection method for protecting the clutch, the analysis and control component having a storage component for storing at least one first temperature threshold, a comparison component for comparing the at least one first temperature threshold with a measured or estimated temperature of the clutch, and a suspension component for suspending the supply of power to the energy storage device by the thermal engine.

[0038] Advantageously, the at least one other power source is an electric motor and the energy storage is at least one battery.

[0039] The invention finally relates to a hybrid motor vehicle, characterized in that it comprises such an assembly, the motor vehicle comprising measuring means for measuring the temperature of the clutch.

[0040] The invention makes it possible to protect the clutch by controlling its temperature, and to control the electrical energy, optimizing the cooling system with little or no impact on the performance and control of the powertrain.

[0041] For vehicles with four powered wheels, this has no effect on the distribution between the front and rear drive axles.

[0042] Advantageously, the motor vehicle is a vehicle having four powered wheels and having a front drive shaft and a rear drive shaft, wherein the front drive shaft is coupled to a front motor and the rear drive shaft is coupled to a rear motor, and the analysis and control component has a conversion component for the front motor, which takes precedence over the conversion component for the rear motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Other characteristics, objects and advantages of the invention will become more apparent upon reading the following detailed description and the accompanying drawings, given as non-limiting examples, in which:

[0044] - Figure 1 is a schematic diagram of a hybrid vehicle that can implement the protection method for protecting a clutch of a heat engine from overheating according to the present invention,

[0045] - Figure 2 An embodiment of a flow chart of a protection method according to an embodiment of the present invention is shown for a thermal clutch with a sufficiently charged and insufficiently charged energy storage, respectively.

[0046] - Figure 3 shows the torque curves provided by the heat engine and the two front and rear electric machines, as well as the virtual limits with and without implementation of the method according to the invention,

[0047] - Figure 4 Three sets of power curves for a motor vehicle having four powered wheels, provided by a heat engine and at least one non-thermal source, are shown by means of a number of graphical scenarios, with and without implementation of the method according to the invention. DETAILED DESCRIPTION

[0048] All figures will be used in combination and during the description relating to one figure, reference may be made to a reference numeral in one of the other figures.

[0049] refer to Figure 1 The present invention relates to a method for protecting a clutch 4 of a hybrid vehicle, the hybrid vehicle comprising: a heat engine 2; at least one non-thermal power source 10, 18, hereinafter referred to as other power source, the at least one non-thermal power source comprising an energy storage device 12; and a clutch 4, the clutch coupling at least the heat engine 2 with at least one wheel drive shaft 8, 26 of the vehicle.

[0050] The invention relates more particularly to an architecture in which the disconnect clutch is positioned between one or more other power sources 10, 18 and the heat engine 2. If the gearbox is closed, one or more power sources 10, 18 can be coupled directly to the wheels 8, 26.

[0051] As will Figure 1 As is apparent from the description of FIG, one or more power sources 10, 18 may advantageously be electric motors, but could be replaced by pneumatic or hydraulic technology, for example.

[0052] The clutch 4 can be operated to respond to activation of the strategy.A transmission 6 is provided having different speed ratios and is coupled to the front powered wheels 8 of the vehicle.

[0053] The exhaust line 50 is arranged with components suitable for treating the exhaust gases, in particular the incomplete combustion products originating from the combustion chambers of the heat engine 2 , such as a particle filter and / or an oxidation catalyst.

[0054] The input shaft of the transmission 6 receives the movement of the clutch 4, and includes a front traction motor 10 as an additional power source, which is powered by a second low-voltage traction battery 12 as an energy storage. In this way, the front motor 10 can send torque to the powered wheels 8 without passing through the clutch 4 by using the different speed ratios provided by the transmission 6.

[0055] 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 stopped. The second traction battery 12 has a low voltage, which may be 220 or 300 volts, for example.

[0056] The second traction battery 12 also supplies power to a rear traction motor 18 , which in turn is coupled via a reduction gear 20 and a differential lock system 22 to a rear differential 24 that distributes the motion to rear wheels 26 of the vehicle.

[0057] An alternator 30 (also called alternator starter) is permanently coupled to the heat engine 2 via a belt 32 and supplies the onboard electrical system, which is called the auxiliary circuit and includes a battery 34 for the very low-voltage auxiliary circuit.

[0058] In addition, the battery 34 of the very 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 electrical energy from the second traction battery 12 or from the front electric machine 10 or the rear electric machine 18 (if the energy level of the second traction battery 12 is insufficient).

[0059] During a release of the brake or accelerator pedal of the vehicle, the electric machines 10 , 18 operate as generators and deliver braking torque to charge the second traction battery 12 and recover energy.

[0060] Analysis and control components (in Figure 1 (not shown) controls the operation of such a powertrain in response to driver demand while optimizing energy consumption and polluting gas emissions according to conventional strategies.

[0061] In this execution example, the second traction battery 12 constitutes the energy storage according to the invention, while the assembly formed by the front traction motor 10 and the rear traction motor 18 constitutes the further power source according to the invention.

[0062] Typically, one or more other power sources 10, 18 (i.e., Figure 1 The motor in has two actuation modes.

[0063] The first mode is an engine mode, in which the power sources provide energy to send tractive or assist torque to the heat engine 2 .

[0064] The second mode is a generator mode in which these power sources power an electrical circuit in order to store energy provided by the heat engine 2 via the energy storage 12. This results in an increase in the temperature of the clutch 4.

[0065] The heat engine 2 and one or more other power sources 10 , 18 provide heat engine torque and tractive or assist torque, respectively, which are used to respond to transient power demands on the part of the operator.

[0066] Said analysis and control means are suitable for controlling the heat engine 2 and one or more other power sources 10 , 18 and for determining the charge level of the energy storage 12 .

[0067] During its operation, the heat engine 2 also supplies the energy storage device 12 with electricity via the alternator or starter alternator, which can also heat up the clutch 4 .

[0068] According to the invention, when the measured or estimated temperature of the clutch 4 exceeds a predetermined first temperature threshold and the rotational speed deviation between upstream and downstream of the clutch 4 exceeds a calibratable predetermined threshold between 0 and 1000 rpm, the analysis and control means request that the heat engine not supply power to the energy storage 12 while keeping the at least one other power source 10, 18 inactive in engine mode.

[0069] This first threshold depends on the type of clutch in question, but can be estimated to be towards 100° C. with a margin of + / - 20% around this value.

[0070] The evaluation and control component can also take into account two predefined charge thresholds of the energy storage device 12 .

[0071] The first threshold may be defined as a priority charge activation threshold, and the second threshold may be defined as a offloadable charge activation threshold. The priority charge threshold is lower than the offloadable charge threshold.

[0072] When the analysis and control component determines that the charge level of the energy storage 12 is below the priority charge activation threshold and the detected temperature of the clutch 4 is above a predetermined first temperature threshold, the analysis and control component keeps the heat engine 2 running to supply power to the energy storage 12 .

[0073] However, suspending the supply of power to the energy storage 12 by the heat engine 2 may not be sufficient to stop or significantly slow down the temperature increase of the clutch 4 .

[0074] In order to predict or prevent maximum heating of the clutch 4, the analysis and control component can at least partially switch the at least one other power source 10, 18 into engine mode when the measured or estimated temperature of the clutch 4 exceeds a predetermined second temperature threshold value that is higher than the first temperature threshold value. The torque transmitted by the clutch 2 and thus the torque provided by the heat engine 2 can thereby be reduced.

[0075] "At least partially" means that in the case of a plurality of other power sources 10, 18, only a portion of these other power sources may be switched. This switching may be gradual and more pronounced as the temperature of the clutch 4 increases.

[0076] As mentioned above, the first temperature threshold may be 100° C. The second temperature threshold may be 180° C., with a range of + / - 20% around each threshold, the first temperature threshold being close to half the second temperature threshold, and the second threshold being lower than the maximum temperature to be experienced by the clutch 4 to ensure protection of the clutch from dangerous heating.

[0077] Thus, before one or more other power sources 10 , 18 are at least partially switched to engine mode, the analysis and control component may first request that the heat engine not supply energy storage 12 when the detected temperature of clutch 4 is above a first temperature threshold of clutch 4 .

[0078] The heat engine 2 is thus less excited and generates less heat, as is the clutch 4 .

[0079] Subsequently, even when the energy storage 12 is not supplied but the detected temperature becomes higher than a second temperature threshold (advantageously lower than the maximum permissible temperature for the clutch 4), a switchover of one or more other power sources 12, 18 is performed in order to take into account the thermal inertia of the clutch, which may lead to a temperature increase even if the supply of energy storage 12 by the heat engine is suspended.

[0080] This conversion is more suitable for the low speed of described engine.On the contrary, under hot clutch and high speed, promptly therefore when clutch is closed, continue to use heat engine 2 and do not increase the temperature of clutch 4 and also be possible.

[0081] Thus, one or more other power sources 10 and 18 are used to limit overheating of the clutch 4. The heat engine 2 is therefore less excited, which makes it possible to reduce the dissipated energy in the clutch 4.

[0082] Thus, the lower the speed increment, the higher the torque that can be transmitted before one or more other electrical sources are used. This mechanism allows a certain maximum power dissipation in the clutch 4. When the temperature of the clutch approaches its maximum temperature, due to reaching a second threshold, the maximum power allowed will be close to the thermal dissipation power of the clutch 4 and will not be exceeded in order not to increase the temperature of the clutch.

[0083] The torque transmitted by the clutch 2 can be reduced until it is eliminated, at which point the heat engine 2 is stopped or no longer used for traction.

[0084] This is possible when the driver's torque demand is reduced or when the energy storage 12 is sufficiently charged.

[0085] Figure 2 A flow chart of the protection method according to the present invention is shown. Reference symbol C denotes a thermal clutch. Thus, either no target charging power inducement is executed (reference symbol A) if the energy store is insufficiently charged, or a target charging power inducement is executed (reference symbol B) if the energy store is sufficiently charged, which results in a stoppage of the power supply to the energy store 12.

[0086] In case B, an attempt is made to postpone the priority power to a later time in order to avoid further heating of the clutch within the acceptable charge range of the energy storage by inducing the priority power.

[0087] If, despite this, priority power is required, the behavior of the powertrain is exactly the same whether the clutch is hot or not, and protecting the clutch from overheating no longer takes priority.

[0088] When there are at least two other power sources respectively coupled to the drive shafts, it is possible that only the first power source 10 of the at least two other power sources 10 , 18 is switched in preference to the at least one second power source 18 .

[0089] However, after the priority switching of the first power source 10, the second power source 18 is also switched when the detected temperature remains higher than the maximum temperature of the clutch 4. This applies successively to a plurality of other power sources present in the hybrid vehicle.

[0090] In particular, in the event that the first power source 10 is saturated, the second power source 18 can take over. Figure 1 The present invention also relates to an assembly comprising a heat engine 2, at least one further power source 10, 18, including an energy storage device 12, a clutch 4, and an analysis and control component. The clutch couples at least the heat engine 2 to at least one wheel drive shaft of the vehicle. This assembly implements the protection method for protecting the clutch 4 described above.

[0091] The protection method is implemented by the analysis and control component, which has a storage component for storing at least one first temperature threshold value, a comparison component for comparing the at least one first temperature threshold value with a measured or estimated temperature of the clutch, and a suspension component for suspending the supply of energy storage 12 by heat engine 2.

[0092] The one or more other power sources 10 , 18 may be electric machines, and the energy storage 12 may be at least one battery.

[0093] The present invention relates to a hybrid motor vehicle comprising an assembly as described above.

[0094] The motor vehicle may be a vehicle having four powered wheels with a front drive shaft coupled to the front motor 10 and a rear drive shaft coupled to the rear motor 18 .

[0095] Each other power source 10 , 18 may be located between the clutch 4 and the wheels of the motor vehicle, or directly on the wheels.

[0096] The analysis and control means may have switching means for switching the front motor 10, which are prioritized over switching means for switching the rear motor 18. However, this is not restrictive.

[0097] The virtual limit for protecting the clutch 4 depends on the temperature of said clutch and on the rotational speed deviation between the main shaft and the crankshaft.

[0098] Although the rear motor 18 often has better efficiency, it is preferred here to implement the rejet on the front motor 10 .

[0099] Since the torque distribution will depend on the speed deviation, it will be very dynamic and therefore the front electric machine is preferred to be used instead of the rear electric machine in order not to affect the torque compensation on the front and rear axles.

[0100] If the front electric machine 10 is not able to assist the separation, the rear electric machine 18 will take over. Advantageously, due to the rapid dynamics of the speed increase, the modification of the torque distribution between the heat engine 2 and one or more other power sources has no effect on the switching laws.

[0101] The energy storage device 12 may be a traction battery. In case of priority charging of the traction battery, the unloading strategy of the heat engine (either by disconnecting from the alternator or by reducing the torque supply power) cannot be applied in order not to drain the traction battery.

[0102] However, it is possible to temporarily change the priority charging threshold by reducing it, so as to give preference to the use of one or more other power sources.

[0103] The front electric machine is used to compensate for the thermal clutch 4 , although the rear electric machine is given priority since this avoids an impact on the torque distribution.

[0104] Figure 3 Two series of torque curves C are shown in Newton-meters (Nm).

[0105] Regarding the first series of upper curves, curve C TAV 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, representing the virtual limit (without the protection method for protecting the clutch from overheating), is higher than the lower horizontal dashed line L, representing the virtual limit (with the protection method implemented).

[0106] For the second series of curves in the lower part, the curve consMth is the torque setpoint curve transmitted by the clutch, the curve conse AR is the torque setpoint curve provided by the rear motor, and the curve conse AV is the torque setpoint curve provided by the front motor.

[0107] The virtual limit Ls is the virtual limit at which the protection method for protecting the clutch from overheating is not implemented and is higher than the virtual limit L at which the method is implemented. The reference signs AV and AR are the virtual limits of the front motor and the rear motor, respectively.

[0108] For a motor vehicle with a thermal engine and at least one non-thermal power source (the vehicle has four powered wheels), Figure 4 Three groups of power curves in kWatt (kW) as a function of time t in seconds (s) are shown.

[0109] In this Figure 4 Seven moments t1, t2, t3, t4, t5, t6, and t7 are marked. When t < t1, the original power is followed (the state of charge SOC of the battery is, for example, 15%). When t1 < t < t2, a decrease in the maximum power is allowed because the clutch is hot and the rotational speed increment is large or non-zero, having no effect on the target charging power. When t2 < t < t4, charging at the maximum power is allowed (which limits the target charging power) because the clutch is hot and has a non-zero rotational speed increment. Thus, protection of the clutch is carried out and the state of charge SOC of the battery is reduced. When t4 < t < t5: The state of charge SOC of the battery continues to decrease. Thus, even in the case of a hot clutch, a minimum charging constraint is started to be required so as not to overly deplete the battery, but since the SOC protection does not reach the target charging setpoint, this minimum charging constraint is not effective. When t5 < t < t6: The state of charge SOC of the battery continues to decrease and the minimum charging constraint becomes effective. Thus, more charging is carried out than allowed by the clutch protection. When t6 < t: The state of charge SOC of the battery drops significantly, which restricts the power limit so that the constraint of the hot clutch is no longer followed at all, but ensures the management of the state of charge SOC of the battery.

[0110] The first group of curves shows the original priority power curve Pp b, 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.

[0111] A second series of curves, below the first series, shows the minimum priority power curve for protecting the charge contained in the energy storage, the original priority power curve, and the priority power curve as a function of the temperature of the clutch, and is similar to the first series of curves but without these three curves being marked.

[0112] Furthermore, the second series of curves shows the integrated priority power curve Psp for protecting the clutch.

[0113] A third series of curves, located below the second series, shows the minimum priority power curve for protecting the charge contained in the energy storage, the original priority power curve, and the priority power curve as a function of the temperature of the clutch, and this third series of curves is similar to the first and second series of curves, but without the three curves being marked.

[0114] Furthermore, the third series of curves shows the coordinated final priority power curve Ppfc.

[0115] In the ellipse O1 of the first series of curves, the clutch heats up. Limitation or even elimination of the power to be drawn from the heat engine by the electrical system including the energy storage is performed in order to avoid further slipping of the clutch.

[0116] In the ellipse O2 of the second series of curves, the clutch heats up but the charge level of the energy storage becomes below the priority charge threshold. Disabling the priority power is performed to ensure minimum charging in order to have a charge level above the priority charge threshold.

[0117] 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 with a hot clutch and high speeds when the clutch is closed, it is possible to continue charging the energy storage without causing an increase in clutch temperature.

[0118] The invention is not limited to the embodiments described and shown, which are given as examples only.

Claims

1. A method for protecting a clutch (4) of a hybrid vehicle, the hybrid vehicle comprising: Heat engine (2); At least one other power source (10, 18), the at least one other power source comprising an energy storage (12); a clutch (4), the clutch coupling at least the heat engine with at least one wheel drive shaft of the vehicle, the at least one other power source (10, 18) 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 heat engine (2), and in which the at least one other power source powers a circuit to store energy provided by the heat engine (2) via the energy storage (12), the heat engine (2) and the at least one other power source (10, 18) providing heat engine torque and traction or assistance torque, the heat engine torque and the traction or assistance torque being used to respond to a momentary power demand on the part of the driver; an analysis and control unit adapted to control the heat engine (2) and the at least one other power source (10, 18) and to determine the charge level of the energy storage (12), characterized in that when the measured or estimated temperature of the clutch (4) exceeds a predetermined first temperature threshold and the speed deviation between upstream and downstream of the clutch (4) exceeds a calibratable predetermined threshold between 0 and 1000 rpm, the analysis and control unit requests that the heat engine not supply power to the energy storage (12) while keeping the at least one other power source (10, 18) inactive in engine mode.

2. The protection method according to claim 1, wherein: The analysis and control component also takes into account two predefined charging thresholds of the energy storage (12), one of which is defined as a priority charging threshold and the other as a removable charging threshold, the priority charging threshold being lower than the removable charging threshold. When the analysis and control component determines that the charging level of the energy storage (12) is lower than the priority charging threshold and the detected temperature of the clutch (4) is higher than the first predetermined temperature threshold, the analysis and control component keeps the heat engine (2) running to supply power to the energy storage (12).

3. The protection method according to claim 1 or 2, wherein: When the measured or estimated temperature of the clutch (4) exceeds a predetermined second temperature threshold, the analysis and control component performs an at least partial conversion of the at least one other power source (10, 18) into engine mode, thereby reducing the torque transmitted by the clutch (4) and thus the torque provided by the heat engine (2).

4. The protection method according to claim 3, wherein: The first temperature threshold is 100° C. and the second temperature threshold is 180° C., with a range of + / - 20% around each threshold.

5. The protection method according to claim 3, wherein: The at least partial conversion of the at least one other power source (10, 18) into engine mode is performed gradually.

6. The protection method according to claim 5, wherein: The at least one other power source (10, 18) includes at least two other power sources respectively coupled to the drive shafts, a first power source (10) of the at least two other power sources (10, 18) being switched in priority to the at least one second power source (18), and, after the priority switching of the first power source (10), when the detected temperature of the clutch (4) remains higher than the second temperature threshold, the at least one second power source (18) is also switched.

7. An assembly comprising a heat engine (2), at least one other power source (10, 18), a clutch (4) and analysis and control components, the at least one other power source comprising an energy storage device (12), the clutch coupling at least the heat engine (2) to at least one wheel drive shaft of the vehicle, characterized in that The component implements a protection method for protecting a clutch (4) according to any one of claims 1 to 6, the analysis and control component having a storage component for storing at least one first temperature threshold value, a comparison component for comparing the at least one first temperature threshold value with a measured or estimated temperature of the clutch, and a suspension component for suspending the supply of power to the energy storage (12) by the heat engine (2).

8. The assembly according to claim 7, wherein The at least one other power source (10, 18) is an electric motor and the energy storage (12) is at least one battery.

9. A hybrid motor vehicle, characterized in that: The hybrid motor vehicle comprises an assembly according to claim 7 or 8, the motor vehicle comprising measuring means for measuring the temperature of the clutch.

10. The hybrid motor vehicle according to claim 9, wherein the hybrid motor vehicle is a vehicle having four powered wheels and is provided with a front drive shaft and a rear drive shaft, wherein the front drive shaft is coupled to a front motor (10) and the rear drive shaft is coupled to a rear motor (18), and the analysis and control component has a conversion component of the front motor (10), and the conversion component of the front motor is prioritized relative to the conversion component of the rear motor (18).

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