JP2001522020A - How to determine slip - Google Patents

Abstract

SUMMARY OF THE INVENTION The present invention relates to a method and apparatus for determining slip in a clutch disposed between a transmission of a drive train and an engine using clutch input speed and wheel speed. In this case, the change in rotation speed was calculated using a mathematical model that records the dynamic characteristics of the drive train, and this change in rotation speed was taken into account when slip was confirmed.

Description

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a method for determining the slip of a clutch arranged in a drive train of a vehicle (Antriebsstrang).

[0002] Clutches arranged between a prime mover and a transmission in a drive train of a vehicle are increasingly operated automatically by controlling an actuator that operates the clutch by a control device according to the driving conditions of the vehicle. It has become. Such an automatically operable clutch may be located behind the transmission. Such automated clutches, on the one hand, significantly increase the operating comfort of the motor vehicle. On the other hand, such automated clutches contribute to lower consumption. This is because the vehicle is driven in a convenient gear with low consumption, in particular in cooperation with an automated transmission. In this case, the automated clutch is interrupted only as needed to reduce the energy consumption of the actuator, reduce the time for operation, and obtain comfort, thereby providing a high slip or tolerance. A slip that is not so large as to be generated is prevented.
Thus, knowledge about clutch slip is necessary for a number of reasons.

[0003] By averaging the rotational speeds of the driven wheels and multiplying the transmission input rotational speed and the respective respective gear ratio effective between the wheels, the clutch output rotational speed is the same as the transmission input rotational speed. Once the number is calculated, the vibrations that occur in the drivetrain (the drivetrain is one system that vibrates itself) are no longer taken into account. As a result, the calculated difference between the measured engine speed (clutch input speed) and the calculated transmission input speed (clutch output speed), based on the vibrations in the drive train, is actually Is evaluated as slip even though no slip exists. In order to obtain a certain degree of certainty in connection with a misinterpretation of the slip, it is customary to introduce a fixed slip limit, in which the aforementioned speed difference is defined as the slip. In order to be evaluated, it needs to be exceeded. In particular, in the case of rocking vibration or surge vibration (Ruckelschwingung) such as when traveling at a very low rotational speed or when a moment jump occurs at the start, such a slip limit needs to be set very high. . This means that during normal driving, even if a slip actually occurs, the slip cannot be recognized, and as a result, the clutch is unnecessarily and strongly worn, and the service life of the clutch is reduced.

An object of the present invention is to provide a method for determining the slip of a clutch disposed between a transmission and an engine of a vehicle without having to measure the clutch output speed and at the time of vibration of the drive train. It is an object of the present invention to provide a method that can detect a slip generated in a clutch without having to consider it.

[0005] A first solution to this problem is defined in claim 1.

According to the present invention, a change in the rotational speed caused based on the dynamic characteristics of the drive train is calculated in consideration of a change in the moment applied to the drive train by the engine. In order for the difference between the measured clutch input speed and the clutch output speed formed from the measured vehicle wheel speed and the total gear ratio to be evaluated as slip, this difference is calculated dynamically. Must be exceeded.

[0007] Dependent claims to 5 describe advantageous variants of the method according to claim 1.

Claim 6 describes another method for solving the problem of the present invention. According to this method, the entire drive train is formed by a mathematical model having measurable state values and measurable excited moments. The clutch output speed is calculated from this mathematical model. The difference between the measured clutch input speed and the calculated clutch output speed is the slip actually present in the clutch.

Claim 7 describes another advantageous embodiment of the method according to claim 6.

[0010] The invention further relates to an apparatus for implementing the method for determining slip described above.

As shown in FIG. 1, the drive train of a motor vehicle has an internal combustion engine 2, which is connected to a transmission 6 via a clutch 4. The transmission 6 is connected to a driven rear wheel 12 via a cardan shaft 8 and a differential 10. The front wheels 1 of the motor vehicle are not driven in the embodiment shown.

The construction of the clutch 4 is known, in particular, a clutch disc 16 connected to the crankshaft of the internal combustion engine 2 and a drive shaft relative to the input shaft of the transmission 6 so as to rotate together. ) With the pressure plate 18 connected thereto, so that the operating lever 20 can release the frictional connection with the clutch disc 16 against the spring force of the disc spring.

The transmission 6 is a general manual transmission, and can be shifted by a shift lever 22.

An actuator (for example, an electric step motor) 20 is provided to operate the operation lever 20, and the actuator 20 is controlled by an electronic control unit 26.

The electronic control unit 26 has a microprocessor, a memory device, an interface and the like in a known manner. The electronic control unit 26 receives, as input signals, signals of a rotation speed sensor 28 for detecting the rotation speed of the clutch disk 16 or the crankshaft of the internal combustion engine, and signals of the actuator 26, the operation lever 20, and the vehicle speed sensors 32 and 34. The signals of the position sensor 30 for detecting the position and, if appropriate, other operating parameters of the drive train, such as the position of the throttle valve of the internal combustion engine 2, etc. are supplied. In addition, the control device 26 is supplied with the rotational speed of the undriven front wheel 14.

The structure and mode of operation of the device described above are well known and will not be described in further detail.

The rotation speed of the rear wheel 12 is detected and multiplied by the total transmission ratio of the transmission 6 and the differential 10, and then the rotation speed of the pressure plate 18 and the rotation speed of the clutch disk 16 calculated in this manner are calculated. The problem that arises when the rotational speed of the pressure plate 18 that is the same as the rotational speed of the transmission input shaft is calculated by obtaining the difference as the slip is as follows.

The entire drive train is a structure that is exposed to vibrations, in which an engine or internal combustion engine 2 that is flexibly suspended inside the vehicle vibrates relative to the vehicle as the main inertia body. However, the vehicle is supported on the ground via rear wheels 12, and the drive train acts as an elastic connecting member.

This oscillating system is shown schematically in FIG. In this case, J _M represents the moment of inertia of the engine, i represents the total transmission ratio of the transmission, c
Represents the spring constant of the drive train.

When the inertia of the engine is excited by a moment jump or moment change ΔM, a vibration having an amplitude ΔM / c is formed at a surge natural frequency (Ruckeleigenfrequenz) ω _Ruckel . This vibration is shown in FIG. 3, where the number of rotations n is shown on the ordinate and the time t is shown on the abscissa.

The maximum angular velocity generated based on this vibration

(Equation 5) Is calculated.

In this equation:

[0023]

(Equation 6)

Δn _dun1 is a rotation speed fluctuation or a rotation speed difference generated based on the engine moment change ΔM. When the difference between the measured rotational speed of the clutch disc 16 and the transmission input rotational speed or the clutch output rotational speed calculated from the average value of the rotational speeds of the rear wheels 12 and the effective total transmission ratio is larger than _Δndyn1. For the first time, it is rated as clutch slip.

The surge frequency ω _Ruckel is based on the respective transmission ratio. The surge frequency is determined based on measurements for each gear or based on vehicle data. From the surge frequency at the first gear, the frequency for another transmission gear ratio is determined.

[0026]

(Equation 7)

The determination of the engine moment change ΔM is made by comparing the engine moment signal with the filtered engine moment signal. The engine moment signal is measured, for example, by using the characteristic fields of the engine speed and the throttle valve position or the characteristic fields of the engine speed and the intake pressure, from which the engine moment at a predetermined value is read. You. Similarly, the engine moment can also be obtained directly from the engine control via a data bus such as CAN-Bus. By passing the engine moment signal through the filter in a known manner with a filter time constant T _F , a filtered engine moment signal is derived from the engine moment signal. The filter time constant T _F must not be too small. Otherwise, the filtered signal will quickly follow the raw signal and the engine moment change ΔM cannot be accurately determined. Preferably, the filter time constant T _F corresponds to twice the period of the surge oscillation. The determination of ΔM is made in advance from the value of the engine moment stored for this purpose.

FIG. 4 shows two views, the upper one showing the difference between the moment signal M _E and the filtered engine moment signal M _{E, F.} The lower curve of the drawings the same as the curve of the upper drawing, which shows the filter time constant T _F, the smaller filter time constant T _F is filtered torque signal M _{E, F} is rapidly approaching the actual engine moment M _E. By determining the moment change ΔM via a comparison of the change signal M _E and the filtered signals _{E, F} , the temporal decay of the drive train oscillation is recorded.

[0029] based on the attenuation of the drive train, the amplitude Δ _n of the surge vibration is reduced I accompanied the passage of time. It is generally not accurate enough to record the above-mentioned type, that is, the damping of the vibration by the time reduction of ΔM. For this reason, the amplitude of the surge oscillation determines the amplitude for the next time step, which takes into account the attenuation of the oscillation with the damping constant D. For a new amplitude the following equation:

[0030]

(Equation 8)

Or (FIG. 5)

[0032]

(Equation 9)

The following applies.

The following further applies:

[0035]

(Equation 10)

During the cycle time of the surge vibration, the control is called p times, or the rotational speed becomes p
The following equation applies for the decay constant k (the decay constant for each control interruption), since it is read twice:

[0037]

[Equation 11]

For simple calculation of κ, the above term (Term) is subjected to series expansion (Reihenentwickelung). Thereby, for example, a first approximation:

[0039]

(Equation 12) Is obtained.

In this case, if it is desired to increase the accuracy, another term (Glieder) of the series expansion may be used.

From the damping effect, the following equation applies for the dynamic slip limit:

[0042]

(Equation 13)

In this manner, two components are obtained for determining the slip limit. That the two components of the slip limit [Delta] n _DYN2 calculated on the basis of the effects of damping and slip limit [Delta] n _dyn1 formed from the engine torque changes ΔM is obtained. In this case, the maximum of the two components is used as the slip limit.

[0044]

[Equation 14]

Unlike the prior art, which works at very high fixed slip limits in order to counteract the effects of vibrations in the drive train, according to the present invention, the actual drive train vibrations were matched. You can work with realistic slip limits.

FIG. 6 shows a flowchart of the above-described method for determining slip.

In step 100, the slip Δn is calculated in a conventional manner by subtracting the measured wheel speed and the transmission input speed detected from the total transmission ratio from the measured engine speed. .

In step 102, the engine moment change ΔM is calculated, for example, as described with reference to FIG.

In step 104, the slip limit _Δndyn1 is calculated from the engine moment change ΔM according to equation (1).

In step 106, a slip limit _Δndyn2 is calculated from the damping effect according to equation (2).

In Step 108, whether [Delta] n _dyn1 is greater than [Delta] n _DYN2 is detected. If yes, in step 110, it is determined [Delta] n _dyn1 is the value of the dynamic slip limit [Delta] n _dyn. If no, in step 112, it is determined that [Delta] n _DYN2 forms a dynamic slip limit [Delta] n _dyn. Next, at step 114, it is checked whether the slip Δn detected in the conventional manner is larger than Δn _dyn . If yes, it is evaluated that a slip has occurred in the clutch. If no, it is evaluated that no slip has occurred in the clutch.

As an alternative to the method described above, a dynamic system “D
At least approximation of all state vectors of live train (gesamter Zustandvektor)
May be reconfigured dynamically. The mathematical violets of the drivetrain for this
The input value and the engine moment M are calculated using the dynamic model. _E And load M_LAnd the comparison between the measured values and the corresponding values of the mathematical model
Done. To this end, drive train measurements and mathematical models
The difference from the calculated value is appropriately weighted in the input of the mathematical model (Gewichtung;
Eating is performed (observed). This allows the mathematical model to be
It is excited to vibrate at the same cycle as the live train. Special for slip determination
Measurement of transmission input speed or clutch output speed.
Possible values are taken from the mathematical model and compared with the measured engine speed.
It is. From the result of this comparison, determine if slip is or is not present
be able to.

FIG. 7 shows a drive train corresponding to FIG. 1. In the embodiment shown in FIG. 7, the throttle valve position sensor 36 and the cardan shaft speed sensor 3
8 and other additional sensors. These additional sensors are likewise connected to an electronic control unit 26 in which the mathematical model is filed.

The problem with the observer in the calculation method described above is that in the special case of a car,
This means that the load moment M _L (vehicle resistance, inclination, etc.) is not recognized. Therefore, it is necessary to determine the load moment ML by failure value evaluation.
For this purpose, measurable values such as the vehicle speed (depending on the wheel speed) and the engine speed can be used. The wheel speed preferably also takes into account the speed of the front wheels 14, but this does not involve a general cost. This is because this rotational speed is detected in any case by the provided ABS sensor.
By known inertia of such engines and vehicles, using a greatly simplified model shown in Figure 8, the evaluation values such as the following for the load moment M _L is determine.

[0055]

(Equation 15)

In this case, J _M is the inertial mass of the engine, L _KFZ is the generated inertial mass moment on the engine side of the vehicle, ω _M is the rotational speed of the engine, and ω _KFZ is the projected on the engine side (projezierte ) The rotational speed of the vehicle.

In the following, a mathematical dynamic model of the vehicle is shown in state form.

X = Ax + Bu In this case, the vector x is a state value (rotational angle, angular velocity), and the vector u is an excited moment (engine moment, load moment). This system is described by a state matrix A. The control matrix B projects the individual excited moments to each state coordinate.

FIG. 9 shows a flowchart for determining the slip from a completely mathematical model as described above. The engine moment as an input value which is measured (for example, obtained from the load of a bearing supporting the engine in the vehicle) or calculated (for example, obtained from information on the rotational speed and throttle valve angle or engine control) is
Acts on the vehicle 120. In the vehicle 10, the measured value is determined by the sensor (12
2). Further, a loading moment is detected (124), as described in connection with FIG. Load moments and engine moments are provided as input values to the dynamic vehicle model (126). Dynamic vehicle model (
From 126), the measured value (122) is mathematically read (128). The difference between the mathematically determined measurement (128) and the directly measured measurement is dynamically weighted (130) and provided to a dynamic model (126). By properly selecting the dynamic weighting, the dynamic model is excited to oscillate with the vehicle, so that the transmission input speed or clutch output speed is calculated and the engine speed or clutch input speed is calculated. Can be compared to From this comparison result, the clutch slip can be calculated directly.

An example for model formation is shown below. FIG. 10 applies to the case of a slipping clutch.

A dynamic model of the vehicle is realized using the model shown in FIG. 10, together with the known inertia of the engine 201, the transmission 203, the vehicle 205, the clutch 202 having a transmittable torque, and the rigidity of the drive train 204. Is done.

[0062]

(Equation 16)

X is a state vector, u is a control vector, A is a state matrix, and B is a control matrix.

[0064]

[Equation 17]

In another embodiment shown in FIG. 1, a model is shown for the case of a non-slip clutch. In this case, the rotation angle of the clutch input and the rotation angle of the clutch output are the same. This unifies the rotational inertia of the engine and the rotational inertia of the transmission.

[0066]

(Equation 18)

X is a state vector, u is a control vector, A is a state matrix, and B is a control matrix.

[0068]

[Equation 19]

Next, a method according to the present invention and an apparatus for performing the method will be described. According to the method of the present invention, the slip calculated from the difference between the engine speed and the driven speed of the transmission or at least the speed of the individual vehicle wheels is:
According to the slip actually present in the clutch and the virtual slip, it is distinguished as a rotational speed difference resulting from the dynamics of the transmission section between the transmission input and the wheels (torsional vibration of the driven shaft between the transmission and the vehicle wheels). Is done.

When a vehicle reaction or clutch operation, implemented as a slip function, is introduced,
A vehicle reaction or clutch operation can be introduced on the actual slip of the clutch and blocked on a virtual slip. For example, as long as a slip is detected, the control / regulator serves to cause the clutch to be engaged.

Accordingly, when a clutch slip occurs in an appropriate running state of the vehicle,
The clutch is controlled and connected. On the other hand, a virtual slip is obtained as a rotational speed difference between the transmission input rotational speed and the driven rotational speed weighted by the full gear ratio, for example, due to the alternating load introduced repeatedly.

In another embodiment, a temperature module / load module for determining clutch temperature / clutch load is implemented in an automatically operable clutch control / adjustment device. Using the vehicle data, the temperature of the clutch or the friction efficiency occurring at the clutch is calculated. Based on the control, the determined reaction takes place in the vehicle or when the clutch is actuated when a limit temperature / limit load is exceeded. The controller controls the introduction or prevention of changes in clutch operation by determining the difference between the slip and the virtual slip.

In a method for determining slip in a clutch, the clutch input speed or the engine speed is measured, the speed of at least one vehicle wheel, and the total gear ratio acting between the clutch output and the vehicle wheel. By measuring the rotation speed of the clutch, the clutch output rotation speed is calculated. In a first embodiment of the method, a rotational speed change _Δndyn is obtained using a mathematical model describing the dynamic characteristics of the drive train. This change in rotational speed is associated with a change in the operating parameters of the drive train and is evaluated as slip when | n _Ki −n _Ka | −Δn _dyn > 0.

The invention further relates to an apparatus for determining a slip based on the above description.

The claims set forth in accordance with the invention are an unbiased proposal for obtaining sufficient patent protection. Applicant reserves the right to request other features than those previously disclosed only in the specification and / or drawings.

The citation used in the dependent claims further limits the subject matter of the main claim according to the features of each dependent claim, but not the sole feature for the features of the referenced dependent claims. It is not a waiver to obtain specific protection.

The subject matter of the dependent claim also forms an independent invention having a configuration independent of the subject matter of the preceding dependent claim.

The invention is not limited only to the embodiments described in the specification. Rather, many modifications and variations are possible within the scope of the invention, in particular, for example, separately from the general description and embodiments and the features or members or method steps described and illustrated in the claims. Examples of combined changes and examples of combined changes,
The components and combinations and / or materials are inventive, provide one novel object or sequence of method steps or methods, and are also related to manufacturing methods, inspection methods and working methods.

[Brief description of the drawings]

FIG. 1 is a diagram showing a drive train of an automobile.

FIG. 2 is a diagram showing a vibration module of a drive train.

FIG. 3 is a diagram showing vibrations generated in a drive train after an engine impact.

FIG. 4 is a curve showing detection of an effective engine moment in each case.

FIG. 5 is a diagram showing buffered vibration of the transmission input rotation speed.

FIG. 6 is a flowchart showing a calculation of a dynamic slip limit.

FIG. 7 shows a drive train similar to FIG. 1 with additional sensors.

FIG. 8 is a diagram showing detection of a load moment.

FIG. 9 is a flowchart showing detection of a transmission input rotation speed.

FIG. 10 is a diagram showing a vibration module of a drive train.

FIG. 11 is a diagram showing a vibration module of a drive train.

[Procedural Amendment] Submission of translation of Article 34 Amendment of the Patent Cooperation Treaty

[Submission date] December 2, 1999 (1999.12.2)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

(Equation 1) 2. The method of claim 1, wherein ΔM = change in engine moment, J _M = inertial moment of engine, f _R = oscillation frequency or surge frequency.

(Equation 2) in this case,

(Equation 3) The method of claim 1, wherein D = buffer constant of surge oscillation and T _R = time interval of surge oscillation.

(Equation 4) 7. The method according to claim 6, wherein M _E = engine moment, J _M = engine moment of inertia, ω _M = engine angular velocity, J _KFZ = total moment of inertia at vehicle wheels, ω _KFZ = angular velocity of vehicle wheels.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0002

[Correction method] Change

[Correction contents]

[0002] Clutches arranged between a prime mover and a transmission in a drive train of a vehicle are increasingly operated automatically by controlling an actuator that operates the clutch by a control device according to the driving conditions of the vehicle. It has become. Such an automatically operable clutch may be located behind the transmission. Such automated clutches, on the one hand, significantly increase the operating comfort of the motor vehicle. On the other hand, such automated clutches contribute to lower consumption. This is because the vehicle is driven in a convenient gear with low consumption, in particular in cooperation with an automated transmission. In this case, the automated clutch is interrupted only as needed to reduce the energy consumption of the actuator, reduce the time for operation, and obtain comfort, thereby providing a high slip or tolerance. A slip that is not so large as to be generated is prevented.
Thus, knowledge about clutch slip is necessary for a number of reasons. WO 90/05866 discloses an apparatus for determining slip, in which the clutch input speed and the clutch output speed are determined by an input shaft and an output shaft. Is determined by a sensor disposed at This known solution is costly based on the arrangement of the two sensors. On the other hand, in the present invention, the slip is determined by taking into account the dynamic characteristics of the drive train, for example, by using the clutch input speed and the wheel speed by a sensor arranged in the drive train. .

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Claims (8)

[Claims] 1. A method for determining the slippage of a clutch arranged between an engine and a transmission in a drive train of a vehicle, comprising measuring a clutch input speed n _Ki and a clutch output speed n _Ka. Using a mathematical model that records the dynamic characteristics of the drive train, in a manner that calculates from the measurement of the rotational speed of at least one vehicle wheel and the total gear ratio acting between the clutch output and the vehicle wheel, calculate the speed change [Delta] n _dyn obtained based on the operating parameter change in the drive train, the speed change _{Δn dyn, | n Ki -n Ka} | -Δn dyn> be evaluated as Slip when 0 A method for determining a slip, characterized in that: 2. The rotational speed change Δn _dyn is determined by using the following equation. 2. The method of claim 1, wherein ΔM = change in engine moment, J _M = inertial moment of engine, f _R = oscillation frequency or surge frequency. 3. The method according to claim 2, wherein the engine moment change ΔM is determined by comparing the engine moment signal with the filtered engine moment signal. 4. The rotational speed change Δn _dyn is determined according to the following equation: In this case, The method of claim 1, wherein D = buffer constant of surge oscillation and T _R = time interval of surge oscillation. 5. A speed change [Delta] n _dyn, a large value from [Delta] n _dyn1 and [Delta] n _DYN2, claims 2 and 4 the method described. 6. A method for determining the slip of a clutch disposed between an engine and a transmission in a drive train of a vehicle, the method comprising measuring a clutch input speed or an engine speed nK _i and determining a clutch output speed. In a method of calculating n _Ka by measuring the speed of at least one wheel, the entire drive train is formed by a mathematical model of the formula: x = Ax + Bu, where x is the state value , U is the excited moment, A is the state matrix,
B is a control matrix of the drive train, wherein the clutch output rotational speed is calculated using the above mathematical model, and a method for determining slip is provided. 7. A calculated according to the following equation load moment acting from the outside on the drive train of the (M _L), Equation 4] 7. The method according to claim 6, wherein M _E = engine moment, J _M = engine moment of inertia, ω _M = engine angular velocity, J _KFZ = total moment of inertia at vehicle wheels, ω _KFZ = angular velocity of vehicle wheels. 8. Apparatus for carrying out the method according to claim 1 in particular.