DE102013103878B4 - Method and control device for adapting a characteristic curve of a separating clutch provided between an internal combustion engine and an electric motor - Google Patents

Abstract

Method for adapting a characteristic curve of a separating clutch (14) provided between an internal combustion engine (12) and an electric motor (18), in which the separating clutch (14) is initially opened while the internal combustion engine (12) is switched off and the electric motor (18) is switched on, wherein the electric motor (18) delivers a torque to a drive shaft (16) that can be coupled to a motor vehicle transmission (22), then the disconnect clutch (14) is at least put into slipping mode and the actual currently applied torque MTKreal of the disconnect clutch (14) is determined, with a At least partial closing of the separating clutch (14) is triggered when the separating clutch (14) was fully open over a defined minimum time interval Δmin2 and a maximum deviation from a time average value of a power input of the electric motor (18) into the drive shaft ( 16) below a defined threshold erts ΔPmax is, while during the determination of the actual moment MTKreal of the separating clutch (14) for the purpose of correcting the characteristic, starting of the internal combustion engine (12) is prevented, during the determination of the actual currently acting torque MTKreal of the separating clutch (14) for the purpose of Correction of the characteristic curve, further transmission of a speed and / or a torque of the internal combustion engine (12) to a display instrument is prevented, and subsequently, with the aid of the actual moment MTKreal of the separating clutch (14), a corresponding setpoint MTKsoll is stored in the characteristic curve for the separating clutch (14). is corrected.

Description

The invention relates to a method and a control device with the aid of which a characteristic curve of a separating clutch provided between an internal combustion engine and an electric motor can be adapted.

Out DE 10 2008 042 685 A1 it is known to start an internal combustion engine of a hybrid motor vehicle with the aid of an electric motor. To this end, in order to start the internal combustion engine, a separating clutch provided between the internal combustion engine and the electric motor is initially closed in a slipping manner, so that the speed of the electric motor changes. In order to adapt a changing characteristic curve of the separating clutch ("adaptation"), a speed change of the electric motor to be expected at a later point in time is calculated on the basis of a setpoint stored in the characteristic curve for the applied torque of the separating clutch and compared with an actual speed change in order to generate a Estimate the adjustment of the setpoint of the characteristic. When the power transmitted from the electric motor to the internal combustion engine via the separating clutch is large enough for the internal combustion engine to start, the adaptation of the characteristic curve is ended.

The post-published DE 10 2011 089 676 A1 discloses a method for adapting a characteristic curve of a separating clutch provided between an internal combustion engine and an electric motor, in which the separating clutch is initially opened while the internal combustion engine is switched off and the electric motor is switched on, the electric motor delivering a torque to a drive shaft that can be coupled to a motor vehicle transmission, subsequently the disconnect clutch is at least put into a slip mode and the actual currently acting torque of the disconnect clutch is determined and subsequently a corresponding setpoint value stored in the characteristic curve for the disconnect clutch is corrected with the help of the actual currently acting torque of the disconnect clutch, with the actual currently acting torque being corrected during the determination At the moment of the separating clutch for the purpose of correcting the characteristic curve, starting of the internal combustion engine is prevented.

DE 10 2011 016 999 A1 , EP 2 014 946 A2 , WO 2008/064 633 A1 and DE 10 2008 027 071 A1 disclose further prior art.

There is a constant need to improve the adaptation of the characteristic curve of a separating clutch between the internal combustion engine and the electric motor of a hybrid motor vehicle.

It is the object of the invention to indicate measures which enable a good adaptation of the characteristic curve of a separating clutch between an internal combustion engine and an electric motor of a hybrid motor vehicle.

The object is achieved according to the invention by a method with the features of claim 1 or claim 2 and a control device with the features of claim 8.

Preferred embodiments of the invention are specified in the subclaims, which can each represent an aspect of the invention individually or in combination.

If a hybrid motor vehicle designed in particular as a “parallel hybrid” is driven purely electrically, at a point in time when a power input from the internal combustion engine is not even provided, the separating clutch can at least partially, that is to say slipping, and / or completely, that is to say essentially without slipping adhesive, can be closed without starting the internal combustion engine. As a result, the characteristic curve of the separating clutch can also be checked and, if necessary, corrected in the purely electric operation of the hybrid motor vehicle. This makes it possible to take into account that the actuation characteristics of the separating clutch and the associated characteristic curve of the separating clutch can also change in the purely electric operation of the hybrid motor vehicle. For example, the separating clutch is designed as a friction clutch with a hydraulic actuation system, the characteristic curve of the separating clutch being able to change as a result of temperature fluctuations occurring within the actuation system during operation of the hybrid motor vehicle. By closing the disconnect clutch in the meantime, at least until it slips, the characteristic curve of the disconnect clutch can also be adapted very precisely in purely electrical operation without causing the internal combustion engine to start unnecessarily, so that at a point in time when the internal combustion engine is actually to be started, the coupling of the Combustion engine to the drive shaft can be done particularly gently and comfortably thanks to the precise information about the current characteristic curve of the separating clutch.

By adapting the characteristic curve of the separating clutch, changes in the characteristic curve of the separating clutch that have occurred in the meantime, for example due to temperature changes and / or wear, can be taken into account and compensated for by a corresponding clutch control system. A particularly precise control of the separating clutch is thereby possible, as a result of which the internal combustion engine is coupled to the electric motor in a particularly gentle and comfortable manner can. In particular, a sudden torque input into the drive shaft and / or into a motor vehicle transmission when the separating clutch is closed can be avoided. The electric motor is designed in particular as an electric machine that can be operated either in motor mode, in generator mode and / or essentially without load. The motor vehicle transmission is in particular an automatic transmission. The drive shaft can be coupled to the motor vehicle transmission via a gear coupling. The gear clutch can be designed as a friction clutch, for example a multi-disc clutch and / or double clutch, or as a hydrodynamic converter. The separating clutch is designed in particular as a friction clutch, which in particular has at least one pressure plate that can be displaced relative to a counterplate, with a travel s for moving the pressure plate being measured in particular in order to be able to identify different operating points of the separating clutch when adapting the characteristic curve.

While determining the actual current attacking moment M _TKreal the separating clutch is prevented from forwarding a speed and / or a torque of the internal combustion engine to a display instrument for the purpose of correcting the characteristic curve.

According to claim 1, an at least partial closing of the separating clutch is triggered if the _separating clutch was fully open _{over a defined minimum time interval Δt min2 and} a maximum deviation from a time average value of a power input of the electric motor into the drive shaft below a defined time interval Δt min2 defined threshold value ΔP _max lies. The characteristic curve of the separating clutch can thereby be adapted at a point in time when a quasi-stationary driving state is present in the purely electric operation of the hybrid motor vehicle. If this stationary driving state has _persisted for the duration of Δt min2, it can be assumed that there is an increased probability that this driving state will continue and that a sudden connection of the internal combustion engine, for example to provide a sudden torque peak, is not necessary. It can therefore be assumed that sufficient time is available in this driving situation to carry out an adaptation of the characteristic curve, wherein in particular a particularly large number of measurements can be carried out, which can improve the accuracy of the adaptation of the characteristic curve. _Equal amounts are preferably used for the time interval Δt _min1 and Δt min2.

According to claim 2, an increase in the power input of the electric motor into the drive shaft is adapted to a power consumption of the switched-off internal combustion engine. The power required to accelerate the inertial mass of the internal combustion engine can be automatically fed to the drive shaft by the electric motor, so that a requested power can continue to be provided at the transmission input of the motor vehicle transmission.

In particular, the actual current attacking moment is determined M _TKreal the separating clutch is broken off for the purpose of correcting the characteristic curve when a start of the internal combustion engine is to be triggered and / or a speed of the internal combustion engine reaches and / or exceeds a defined maximum speed nmax and / or a power input of the electric motor into the drive shaft a defined maximum power Pmax reaches and / or exceeds and / or a defined number of determinations of the actual currently attacking moment M _TKreal the separating clutch was carried out at the same and / or different operating points of the separating clutch. The adaptation of the characteristic curve can be terminated when the adaptation has taken place with a sufficient desired accuracy, undesired operating states have been reached or the power of the electric motor is required in some other way, in particular to start the internal combustion engine. This prevents the normal driving operation of the hybrid motor vehicle from being adversely affected by the adaptation of the characteristic curve.

In particular, an adjustment path s of the separating clutch when closing and / or opening the separating clutch is used to determine the actual currently applied torque M _TKreal the separating clutch is adjusted more slowly for the purpose of correcting the characteristic curve than when the separating clutch is closed for the purpose of starting the internal combustion engine and / or than when the separating clutch is opened for the purpose of uncoupling a started internal combustion engine from the drive shaft. A sudden change in performance at the transmission input of the motor vehicle transmission can thus be reliably avoided even if changes in the characteristic curve of the separating clutch have occurred in the meantime. In addition, several determinations of the actual torque currently applied can thereby be assigned to a specific operating point of the separating clutch M _TKreal be carried out more easily.

In particular, during the determination of the actual currently attacking moment M _TKreal the separating clutch for the purpose of correcting the characteristic is prevented from supplying fuel to the internal combustion engine and / or from triggering an ignition of a fuel mixture within the internal combustion engine. An unintended one Starting the internal combustion engine can thus be safely avoided. If a signal is present during the adaptation of the characteristic curve, as a result of which the internal combustion engine is to be started, it may already be sufficient to open the fuel supply to the internal combustion engine and / or switch on the ignition so that the internal combustion engine can be started particularly quickly in response to the signal without fully opening the clutch and closing it again to start the internal combustion engine.

Preferably, an at least partial closing of the separating clutch is triggered when the _separating clutch was completely opened over a defined minimum time interval Δt min1. As a result, the characteristic curve of the separating clutch can be adapted at regular time intervals, even if actuation of the separating clutch is not provided in the current operating mode of the hybrid motor vehicle. Changes in the characteristic curve occurring during the time interval of Δt _min1 can thereby already be taken into account.

In particular, during the determination of the actual currently attacking moment M _TKreal an amount of zero is transmitted from the separating clutch to the display instrument for the speed and / or the torque of the internal combustion engine. This prevents a driver from being irritated as a result of the display of a speed different from zero and / or a torque of the internal combustion engine other than zero even though the internal combustion engine is switched off in such a way that he initiates driving measures that are inadequate for the current driving situation, which for example lead to an unnecessarily increased Fuel consumption.

In particular, there are several setpoint values in the characteristic M _TKsoll stored as a function of a travel s of the separating clutch, the touch point in particular being stored in the characteristic curve, the adjusting travel s of the separating clutch being determined at least after the clutch has reached slip operation. The individual operating points of the separating clutch can be identified and a meaningful comparison of M _TKreal With M _TKsoll be ensured. At the touch point, when the separating clutch is closed, the sides of the separating clutch to be coupled contact for the first time and this defines the beginning of the slipping operation of the separating clutch. From the touch point on, the applied torque of the disconnect clutch is greater than zero. The touch point can be identified particularly easily. The touch point can in particular be used as a reference variable for the characteristic curve, whereby the effect of wear on friction linings can be taken into account automatically.

The actual currently attacking moment is preferably used M _TKreal the separating clutch with the corresponding setpoint shown in the characteristic curve M _TKsoll for the separating clutch and it takes place in the event of a sufficient deviation ΔM of the actual currently applied torque M _TKreal the separating clutch from the corresponding setpoint shown below in the characteristic M _TKsoll the correction of the corresponding setpoint below in the characteristic M _TKsoll , whereby in particular the corresponding setpoint value laid down in the characteristic curve M _TKsoll by the actual currently attacking moment M _TKreal the clutch is replaced. The characteristic curve is only corrected if there is a sufficient deviation, which is preferably significantly greater than deviations due to measurement inaccuracies to be expected. This avoids unnecessary correction work when adapting the characteristic.

A plurality of actual moments that are currently acting are particularly preferred for a specific operating point of the separating clutch M _TKreal of the separating clutch is determined, whereby for the correction of the corresponding setpoint value laid down in the characteristic curve M _TKsoll a mean value of the several actual currently attacking moments M _TKreal is used, in particular the first determined value for M _TKreal and the last determined value for M _TKreal can be discarded for determining the mean value. If the first and the last value M _TKreal , the during the triggered and for the determination of the several actual currently attacking moments M _TKreal If the operating point of the separating clutch was determined to be constant, then inaccuracies, for example due to transient boundary conditions, for example transient phenomena, can be avoided. The accuracy of determining M _TKreal can thereby be increased.

The actual currently attacking moment is preferably used M _TKreal of the separating clutch is determined for the touch point of the separating clutch and the characteristic curve is determined by a difference in the actual currently applied torque M _TKreal the separating clutch to the corresponding setpoint shown in the characteristic curve M _TKsoll shifted in parallel for the disconnect clutch, in particular the actual currently applied torque M _TKreal of the disconnect clutch for the touch point of the disconnect clutch, the first determined actual currently applied torque M _TKreal the disengaging clutch after the transmission clutch begins to slip. An interim change in the adjustment path s of the separating clutch due to wear of the friction linings and / or an intermediate readjustment of the required adjustment path s of the separating clutch by means of an adjusting device can thereby be easily taken into account. A complete check of the characteristic curve over the entire operating range can thereby be simplified or avoided.

The invention also relates to a control device for adapting a characteristic curve of a separating clutch provided between an internal combustion engine and an electric motor, the control device being designed to carry out the method, which can be designed and developed as described above. In particular, the control device is connected, preferably via a CAN bus, to at least one corresponding measuring device and / or at least one further control device, in particular a clutch control device for a transmission clutch, in order to determine suitable values for determining M _TKreal to be able to read. The control device has, in particular, an arithmetic unit in order to use the read-in data M _TKreal to be able to calculate and in particular to be able to output it via an output port in order to be able to adapt the characteristic curve. By closing the separating clutch in the meantime, at least up to the slip mode, a very precise adaptation of the characteristic curve of the separating clutch can also take place in purely electrical operation without causing an unnecessary start of the internal combustion engine, so that at a time when the internal combustion engine is actually to be started, the coupling of the Internal combustion engine to the drive shaft can take place particularly gently and comfortably through the precise information obtained with the help of the control device about the currently present characteristic curve of the separating clutch.

• 1: eine schematische Prinzipdarstellung eines Antriebstrangs eines Hybridkraftfahrzeugs und
• 2: ein schematisches Diagramm eines zeitlichen Verlaufs von Drehzahl und Drehmoment bei der Durchführung des erfindungsgemäßen Verfahrens.

In the following, the invention is explained by way of example with reference to the attached drawings using preferred exemplary embodiments, the features shown below being able to represent an aspect of the invention both individually and in combination. Show it:

• 1 : a schematic representation of the principle of a drive train of a hybrid motor vehicle and
• 2 : a schematic diagram of a time profile of speed and torque when carrying out the method according to the invention.

The in 1 shown drive train 10 a hybrid motor vehicle has an internal combustion engine 12th on who has a disconnect clutch 14th with a drive shaft 16 can be, with the drive shaft 16 at the same time the rotor of an electric motor 18th is. The drive shaft 16 can be via a gear coupling 20th with a motor vehicle transmission designed in particular as an automatic transmission 22nd be coupled. The motor vehicle transmission 22nd can have a differential gear 24 with drive wheels 26th be connected.

In the in 2 The diagram shown is the speed n and the torque M of the internal combustion engine 12th and the electric motor 18th over time t when an adaptation of the characteristic curve of the separating clutch is carried out 14th applied. After a time interval Δt _min without adapting the characteristic curve of the separating clutch 14th takes place at a start time 28 the initiation of the adaptation of the characteristic curve of the separating clutch 14th . For this purpose, first a speed n _EM of the electric motor 18th increased, but at the same time a speed n _G of the motor vehicle transmission 22nd is held stationary. The travel s of the separating clutch 14th is changed in the closing direction up to a moment in time 30th for the first time a currently attacking moment M _TKreal the disconnect clutch 14th is greater than zero. During the slipping operation of the disconnect clutch 14th The characteristic curve of the separating clutch is then adapted 14th , in particular several provisions of M _TKreal at different operating points of the disconnect clutch 14th can be carried out to the stored characteristic curve of the separating clutch 14th to be corrected temporarily or permanently. During the adaptation of the characteristic curve of the separating clutch 14th is power to the switched off internal combustion engine 12th transmitted so that the speed n _VM of the internal combustion engine 12th can easily increase. The disconnect clutch can then be used 14th to be reopened so that at a termination time 32 the slipping operation of the disconnect clutch 14th is finished and not a moment M _TKreal on the disconnect clutch 14th there is more. The switched off internal combustion engine 12th can run out, so the speed n _VM of the internal combustion engine 12th gradually drops to zero. At the same time, the speed n _EM of the electric motor 18th be reduced until the speed n _EM of the electric motor 18th the requested speed is just sufficient n _G of the motor vehicle transmission 22nd provide.

Claims (8)

Method for adapting a characteristic curve of a separating clutch (14) provided between an internal combustion engine (12) and an electric motor (18), in which the separating clutch (14) is initially opened while the internal combustion engine (12) is switched off and the electric motor (18) is switched on , the electric motor (18) delivering a torque to a drive shaft (16) that can be coupled to a motor vehicle transmission (22), then the separating clutch (14) is at least put into slipping mode and the actual currently applied torque M _{TKreal of} the separating clutch (14) is determined , an at least partial closing of the separating clutch (14) is triggered when the _separating clutch (14) was fully open over a defined minimum time interval Δ min2 and over the defined minimum time interval Δ _{min2 is} a maximum deviation from a time average value of a power input from the electric motor (18) into the drive shaft (16) below a defined threshold value ΔP _max , with the actual moment M _{TKreal of} the separating clutch (14) being determined. For the purpose of correcting the characteristic, starting of the internal combustion engine (12) is prevented, while a speed and / or torque of the internal combustion engine continues to be passed on _{during the determination of the actual currently applied torque M TKreal of the separating clutch (14) for the purpose of correcting the characteristic} (12) is prevented on a display instrument, and subsequently _{a corresponding setpoint M TKsoll} for the separating clutch (14) stored in the characteristic curve is _{corrected with the aid of the actual currently applied torque M TKreal of} the separating clutch (14). Method for adapting a characteristic curve of a separating clutch (14) provided between an internal combustion engine (12) and an electric motor (18), in which the separating clutch (14) is initially opened while the internal combustion engine (12) is switched off and the electric motor (18) is switched on , the electric motor (18) delivering a torque to a drive shaft (16) that can be coupled to a motor vehicle transmission (22), then the separating clutch (14) is at least put into slipping mode and the actual currently applied torque M _{TKreal of} the separating clutch (14) is determined , whereby during the determination of the actual currently acting torque M _{TKreal of} the separating clutch (14) for the purpose of correcting the characteristic curve, starting of the internal combustion engine (12) is prevented, whereby during the determination of the actual currently acting torque M _{TKreal of} the separating clutch (14) for The purpose of correcting the characteristic curve continues to be a transmission of a speed and / or a Torque of the internal combustion engine (12) is suppressed on a display instrument, with an increase in the power input of the electric motor (18) in the drive shaft (16) being adapted to a power consumption of the switched-off internal combustion engine (12), and then with the help of the actual moment M _{TKreal of} the separating clutch (14), a corresponding setpoint value M _TKsoll stored in the characteristic curve for the separating clutch (14) is corrected. Procedure according to Claim 1 or 2 , in which during the determination of the actual moment M _{TKreal of} the separating clutch (14) for the purpose of correcting the characteristic curve, a fuel supply to the internal combustion engine (12) and / or an ignition of a fuel mixture within the internal combustion engine (12) is prevented. Procedure according to Claim 2 , in which an at least partial closing of the separating clutch (14) is triggered if the _separating clutch (14) was fully opened over a defined minimum time interval Δt min1. Method according to one of the Claims 1 to 4th , in which an amount of zero is transmitted to the display instrument for the speed and / or the torque of the internal combustion engine (12) during the determination of the actual currently applied torque M _{TKreal of the separating clutch (14).} Procedure according to Claims 1 or 2 , in which the determination of the actual currently applied torque M _{TKreal of} the separating clutch (14) is aborted for the purpose of correcting the characteristic curve if a start of the internal combustion engine (12) is to be triggered and / or a speed of the internal combustion engine (12) a defined maximum Speed nmax reaches and / or exceeds and / or a power input of the electric motor (18) into the drive shaft (16) reaches and / or exceeds a defined maximum power Pmax and / or a defined number of determinations of the actual moment M _{TKreal of} the separating clutch (14) was carried out at the same and / or different operating points of the separating clutch (14). Procedure according to Claim 1 or 2 , in which an adjustment path s of the separating clutch (14) when closing and / or opening the separating clutch (14) for the determination of the actual moment M _{TKreal of} the separating clutch (14) is adjusted more slowly for the purpose of correcting the characteristic curve than when closing the separating clutch (14) for the purpose of starting the internal combustion engine (12) and / or when opening the separating clutch (14) for the purpose of uncoupling a started internal combustion engine (12) from the drive shaft (16). Control device for adapting a characteristic curve of a separating clutch (14) provided between an internal combustion engine (12) and an electric motor (18), the control device for carrying out the method according to one of the Claims 1 to 7th is prepared.

Images