Method for protecting a hybrid clutch of a hybrid powertrain of a vehicle

Abstract

The present invention relates to a method for protecting a hybrid clutch of a hybrid powertrain of a vehicle, wherein an internal combustion engine (2), a first electric motor (4) arranged on the internal combustion engine side and a second electric motor (6) arranged on the driven side are connected or disconnected with a driven device (7) of a hybrid powertrain (1) via a hybrid clutch (5), in such a way that the torque output by the internal combustion engine (2) and / or the first electric motor (4) and / or the second electric motor (6) is transmitted to a drive wheel (7) of the hybrid powertrain (1). In the method, when an undesirable slip speed (Δn S ), a torque is applied to the first motor (4) to compensate for the undesirable slip speed (Δn S ).

Description

Technical Field

[0001] The present invention relates to a method for protecting a hybrid clutch of a hybrid powertrain of a vehicle, wherein an internal combustion engine, a first electric motor arranged on the internal combustion engine side, and a second electric motor arranged on the driven side transmit torque to a driven device of the hybrid powertrain through a hybrid clutch, in the following manner: the torque output by the internal combustion engine and / or the first electric motor and / or the second electric motor is transmitted to the drive wheels of the hybrid drive device. Background Art

[0002] From the German patent application with application number 10 2018 126 881.5, which has not yet been published by the applicant, a hybrid module in a powertrain is known, which has an internal combustion engine and two electric motors, wherein the first electric motor is rigidly connected to the internal combustion engine and the second electric motor is connected to the vehicle's driven device, wherein a hybrid clutch is arranged between the first electric motor and the second electric motor.

[0003] A method for protecting an automatically actuated clutch of a vehicle from overload is known from DE 10 2005 029 566 A1, wherein the driving condition of the vehicle is determined and the energy input to the clutch is continuously detected. Depending on the determined driving condition and the energy input, the overload state can be reduced or completely avoided by targeted intervention in vehicle management.

[0004] DE 10 2009 014 467 A1 discloses a method for controlling an automatic friction clutch, wherein the engine torque of an internal combustion engine is reduced when the transmission capacity of the friction clutch is too low. When a preset engagement travel is exceeded and the slip of the friction clutch is exceeded, the engine torque is reduced according to the slip. This reduction of the engine torque of the internal combustion engine has the following disadvantages: the ignition of the internal combustion engine is interrupted, which leads to the discharge of unburned gasoline, which can lead to environmental pollution and an increased risk of fire. In addition, despite the torque desired by the driver, no acceleration or only negative acceleration of the vehicle is experienced, which is uncomfortable for the driver. Summary of the invention

[0005] The object of the present invention is to specify a method for protecting a hybrid clutch of a hybrid drive train, wherein, if an undesirably increased slip speed is detected, mechanical component protection of the hybrid clutch is increased and environmental protection is improved.

[0006] According to the invention, this object is achieved in that, when an undesired slip speed occurs at the hybrid clutch, a torque is applied to the first electric motor in order to compensate for the undesired slip speed. Compensation of the undesired slip speed thus allows normal continued operation of the hybrid drive train, wherein not only environmental protection is improved, but also the protection of the mechanical components of the clutch is improved by reducing the thermal load on the friction lining of the hybrid clutch. Driving comfort is not impaired in this regard.

[0007] Advantageously, a speed control is activated for setting a predefined target speed for the first electric motor. As a result, the first electric motor is controlled at a speed whose magnitude corresponds to the speed difference of the hybrid clutch on the clutch input side and the clutch output side. As a result, the slip speed can be reliably compensated.

[0008] In one embodiment, the preset target speed corresponds to the actual speed of the second electric motor. Since the second electric motor is in operation, the same speed is set on both sides of the hybrid clutch by compensating the speed of the first electric motor, so that slip can be easily overcome.

[0009] In one variant, the first electric motor is used as a generator to provide energy to the second electric motor, thereby increasing the efficiency of the second electric motor during electric driving, in that urban driving can be performed emission-free at low speeds.

[0010] In one embodiment, the missing torque of the internal combustion engine is provided by the second electric motor. This makes it possible to dispense with the adjustment of the ignition angle of the internal combustion engine control device. This prevents unburned fuel from being introduced into the environment, which in turn contributes to environmental protection. In addition, it is ensured that the same speed always exists on both sides of the hybrid clutch, so that the maximum clutch torque can be transmitted by the hybrid clutch.

[0011] In another embodiment, the current slip speed of the hybrid clutch is monitored, and the occurrence of an undesirable slip speed is detected when the current slip speed exceeds a predefined slip speed threshold, thereby quickly triggering the proposed method to suppress an undesirable slip state in advance, which could cause damage to the hybrid clutch.

[0012] In one embodiment, the predefined slip speed threshold is less than or equal to a value of 10 revolutions per minute, so that even at very low slip speeds, which may occur, for example, due to mechanical or electrical faults, measures can be taken to completely close the hybrid clutch during operation of the hybrid drive train.

[0013] In one variant, the hybrid clutch is moved in the closing direction before compensating for the undesired slip speed, wherein the slip speed compensation is triggered if the hybrid clutch cannot be closed. With the closing of the hybrid clutch, the unforeseen slip should be overcome quickly.

[0014] Alternatively, before compensating for the undesired slip speed, the hybrid clutch is moved in the disengagement direction, wherein the slip speed compensation is triggered if the hybrid clutch cannot be disengaged. Disengagement of the hybrid clutch prevents the hybrid drive from being operated with the internal combustion engine, but ensures that mechanical damage to the hybrid clutch is avoided. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The present invention allows for many embodiments, one of which will be explained with reference to the figures shown in detail in the accompanying drawings.

[0016] The accompanying drawings show:

[0017] Figure 1 An embodiment of a hybrid powertrain for carrying out the method according to the invention is shown.

[0018] Figure 2 An embodiment of the method according to the invention is shown. DETAILED DESCRIPTION

[0019] Figure 1 , an exemplary embodiment of a hybrid drive train 1 is shown, with the aid of which the method according to the invention is carried out. The hybrid drive train 1 comprises an internal combustion engine 2, which is coupled to a first electric motor 4 in a rotationally fixed manner via its crankshaft 3. The first electric motor 4 is connected to the clutch input side of a hybrid clutch 5. The clutch output side of the hybrid clutch 5 is coupled to a second electric motor 6, which is connected to wheels 7 serving as drive elements.

[0020] exist Figure 2 1 shows an embodiment of a method according to the invention, which is stored in the software of a clutch controller (not shown further) of a hybrid drive train 1. The method includes a clutch protection strategy. The method is initialized in frame 100. In frame 110, the slip speed Δn is checked. S Is it greater than the predetermined slip threshold S S The slip speed is determined in the clutch controller from two speeds n occurring on the input side and the output side of the hybrid clutch 5. E , n A If this is the case, the undesired slip speed Δn is inferred S , because the torque transmitted by the hybrid clutch 5 is less than the desired rated torque of the hybrid clutch 5 .

[0021] Subsequently, a transition is made to frame 120, where an attempt is made to close the hybrid clutch 5. If this is possible, a return is made to frame 110 and further states of the hybrid clutch 5 are monitored with respect to undesired slip. If it is determined in frame 120 that the hybrid clutch 5 cannot be closed, an attempt is made to open the clutch in frame 130. When the hybrid clutch 5 is opened, the friction power and thus the clutch temperature should decrease. If this is successful, a return is made to frame 110.

[0022] If the hybrid clutch 5 cannot be disengaged, the speed control for the first electric motor 4 is activated in block 140 . The speed control operates in this case in such a way that the actual speed n of the second electric motor 6 is set to Ist The target speed n of the first electric motor 4 is preset z The first electric motor 4 absorbs the non-transmittable torque of the hybrid clutch 5 as a braking torque. As a result, the slip speed Δn is completely eliminated. S In this way, acceleration of the hybrid drive train 1 is inhibited. Undesired acceleration does not impair driving comfort. Subsequently, in block 150 , the missing torque of the internal combustion engine 2 that can no longer be transmitted by the hybrid clutch 5 is compensated by the additional torque of the second electric motor 6 . The energy for this is provided by the first electric motor 4 .

[0023] Description of Reference Numerals

[0024] 1 Hybrid powertrain 2 Internal combustion engine 3 Crankshaft 4 First electric motor 5 Hybrid clutch 6 Second electric motor 7 Wheel Δn S Slip speed threshold n E Input speed n A Output speed S S Slip speed threshold value n Z The target speed n of the first electric motor Ist The actual speed of the second electric motor.

Claims

1. A method for protecting a hybrid clutch, the hybrid clutch being used in a hybrid powertrain of a vehicle, wherein: An internal combustion engine (2), a first electric motor (4) arranged on the internal combustion engine side, a hybrid clutch (5), a second electric motor (6) arranged on the driven side, and a driven device are connected in sequence in such a way that the torque output by the internal combustion engine (2) and / or the first electric motor (4) and / or the second electric motor (6) is transmitted to a drive wheel (7) of the hybrid powertrain (1), characterized in that when an undesirable slip speed (Δn S ), a torque is applied to the first motor (4) to compensate for the undesirable slip speed (Δn S );in, In compensating for the undesired slip speed (Δn S ), the hybrid clutch (5) is moved in the closing direction, wherein when the hybrid clutch (5) cannot be closed, the slip speed (Δn S ), or In compensating for the undesired slip speed (Δn S ), the hybrid clutch (5) is moved in the disconnection direction, wherein when the hybrid clutch (5) cannot be disconnected, the slip speed (Δn S ) compensation.

2. The method according to claim 1, characterized in that Used to set the preset target speed (n z ) is used to activate the first motor (4).

3. The method according to claim 2, characterized in that The preset target speed (n z ) corresponds to the actual speed (n Ist ).

4. The method according to claim 1, 2 or 3, characterized in that: The first electric motor (4) acts as a generator to provide energy to the second electric motor (6).

5. The method according to claim 4, characterized in that The missing torque of the internal combustion engine (2) is provided by the second electric motor (6).

6. The method according to any one of the preceding claims 1 to 3, characterized in that Monitor the current slip speed (Δn) of the hybrid clutch (5) S ), and when the current slip speed (Δn S ) exceeds the preset slip speed threshold (S S ), an undesirable slip speed (Δn S ).

7. The method according to claim 6, characterized in that The preset slip speed threshold (S S ) is less than / equal to ten revolutions per minute.

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