WO2003086806A1

WO2003086806A1 - Control device and method for controlling engine torque and clutch torque in a drive train

Info

Publication number: WO2003086806A1
Application number: PCT/DE2003/001188
Authority: WO
Inventors: Wolfgang Niessen
Original assignee: Luk Lamellen Und Kupplungsbau Beteiligungs Kg
Priority date: 2002-04-10
Filing date: 2003-04-10
Publication date: 2003-10-23
Also published as: DE10316446B4; DE10316446A1; FR2838389A1; FR2838389B1

Abstract

The invention relates to a method for controlling engine torque and clutch torque, after a gearshift, in a drive train of a vehicle which comprises a transmission and an engine. According to said method, the clutch torque (Tcl) is increased to a defined value and the engine torque (Te) is simultaneously controlled in such a manner that the slip occurring on the clutch is decreased. The invention further relates to a control device for a drive train of a vehicle that comprises an engine and a transmission coupled via at least one clutch, especially for carrying out the inventive method. The inventive control device comprises at least one engine control device and at least one transmission control device which control the engine torque (Te) and the clutch torque (Tcl) in such a manner that after a gearshift the torques are built up in continuous a manner.

Description

Control device and method for controlling an engine torque and a clutch torque in a drive train

The present invention relates to a control device and a method for controlling an engine torque and a clutch torque in a

Drive train of a vehicle with a transmission and an engine after a gear change.

In an automated manual transmission, a torque build-up can be carried out after a gear change in which the engine torque is linear from one

Initial value is increased to the driver's desired torque. The initial value depends on the gear and the accelerator pedal position. In parallel, it can

Clutch torque can be increased so that it is above the engine torque, while it is reduced with decreasing slip. It can happen that the transmissible clutch torque of the still slipping clutch exceeds the torque that the clutch transmits a short time later when the

Coupling is in the sticking state. This means that the

Vehicle acceleration during re-engagement can become greater than immediately afterwards. This increase in acceleration can be experienced as uncomfortable and comfort-reducing by the vehicle's occupants.

At the start of the torque build-up, the slip on the clutch can be very large. It follows that the clutch torque does not increase steadily, but is increased abruptly. This in turn can generate vibrations in the drive train, which can also have a noticeable impact on comfort.

Furthermore, it can happen that the clutch torque increases during the slipping phase above the value which is later transmitted by the clutch. In such a case, a higher moment is transmitted to the wheels shortly before the transition from slipping to sticking than afterwards. This means that the vehicle acceleration is excessive, which can also reduce driving comfort. The invention is based on the object of proposing a control device and a method for controlling an engine torque and a clutch torque in a drive train of a vehicle in order to enable an improved torque build-up, in particular after a gear change.

In terms of method, this object is achieved by a method for controlling an engine torque and a clutch torque in a drive train of a vehicle having a transmission and an engine after a gear change, in which the clutch torque is increased to a predetermined value, and in that the engine torque is controlled in such a way, that the slip on the clutch is reduced.

Accordingly, the method according to the invention realizes a moment build-up that is as constant as possible, especially after a gear change, so that the build-up of the acceleration of the vehicle from zero to the target acceleration is made possible without local extremes.

In the strategy according to the invention, the clutch torque can, for example, preferably be increased linearly from the value 0 to a value which corresponds to the clutch torque immediately after the transition to the clutch becoming stuck. It is also possible to use other values. The value of the clutch torque T _C | ₂ can be calculated by the following equation:

_τ _ ^J V, τ ¹ e, d - i ^l - J e. T ^k r L „i - ^'

where T _{Θ, d is} the engine torque or driver's desired torque requested by the driver, J _v the moment of inertia of the vehicle, i the translation, J _e the moment of inertia of the engine and T _r the sum of all moments acting on the vehicle. According to a further development of the invention, the engine torque can preferably be controlled at the same time in such a way that the slip is reduced precisely when the clutch torque reaches the aforementioned value when the clutch sticks. It is also conceivable that the engine torque again corresponds to the driver's desired torque from this point in time.

Within the scope of a further development of the invention it can be provided that when e.g. B. the engine torque cannot be controlled precisely enough, e.g. B. the engine speed is additionally controlled by modulating the clutch torque. However, care should be taken to ensure that the clutch torque increases monotonously during recoupling. This type of control strategy can also be used as a so-called pilot control.

If the clutch is stuck, the equation of motion of the motor can be calculated using the following equation

J _e - ώ _e = T _e -T _c ] and the equation of motion of the vehicle by the following equation

j _v - ^ = τ _{r +} i -τ: _t l, where T _d ^* denotes the clutch torque transmitted by the clutch and ω _gb i the speed of rotation of the transmission input shaft.

Furthermore, the sum of all moments T _r acting on the drive train can be calculated using the following equation:

T = ώ - i - T

where ώ _e denotes the speed acceleration of the engine.

In terms of the device, the object on which the invention is based can be achieved by a control device for a drive train of a vehicle having an engine and a transmission coupled via at least one clutch, in particular for carrying out the proposed method, are solved, in which at least one engine control unit and at least one transmission control unit are provided, which control the engine torque and the clutch torque in such a way that after a gear change, the torque build-up is as constant as possible.

Further advantages and advantageous configurations result from the subclaims and the drawings described below. Show it:

Figure 1 is a schematic view of a drive train with a clutch, and

Figure 2 is a flowchart of a possible embodiment of the invention

Process.

A model of a drive train is indicated schematically in FIG. 1, by means of which the physical behavior of the drive train is described. The motor has the moment of inertia J _e and can deliver the adjustable motor torque T _e , which is the torque of the internal combustion engine. The speed of rotation of the motor is designated ω _e . The clutch can transmit a torque whose amount is less than or equal to T _c ι. If the clutch slips, this amount is exactly equal to the value of T _c ι; if the clutch is stuck this is at most T _C | The transmissible torque of the clutch T _c ι is adjustable. A ratio i is provided between the clutch and the vehicle. The speed of rotation of the left side of the gear ratio, i.e. the transmission _input shaft, is denoted by ω _gb i. The vehicle has the moment of inertia J _v . From the outside, the vehicle is affected by the driving resistance, which is made up of rolling resistance, air resistance and downhill force. The sum of all moments acting on the vehicle is denoted by T _r .

FIG. 2 shows a flow diagram of a possible embodiment of the method according to the invention. The individual process steps can be seen from the flow chart. At the beginning of the procedure, it is checked whether the clutch is stuck in the drive train. If the new gear is to be engaged, the clutch torque T _c ι ₂ can be calculated using the following equation 1:

where T _e , _d denotes the engine torque T _Θ requested by the driver. To be able to solve the right side of equation 1, T _r must be known. When the clutch is stuck, the equations of motion for the engine and the vehicle are given by the following equations:

J -ώ = T -τ Eq. 2

ω „J. - = T + i - T, Eq. 3

where T _c ^* _{l is} the torque transmitted by the clutch. Eliminating this quantity from equations 2 and 3 and solving for T _r leads to the following equation 4:

T _r can be calculated from this equation, where ώ _{e is} determined by the numerical derivative of ω _e . In the method according to the invention, the clutch torque T _c ι becomes linear during the torque build-up from 0 to T _C | ₂ increased:

s - t Eq. 5

where s is the rate of moment build-up. The duration τ results from equation 6:

r = ^ GI. 6

The further steps or demands of the strategy can be formulated as follows:

ω _e (τ) = ω _εbi (τ) Eq. 7

T _e (τ) = T _etd (τ) Eq. 8th

where T _ed (τ) is the driver's desired torque at the end of the torque build-up. The assumption is made here that this is approximately constant; from this follows T _ed (τ) = T _ed (t) - T _ed . The rotational speeds of the left and right sides from equation 7 can be determined by integrating equations of motion 2 and 3:

+ i ^■ T _cl (t)) dt Eq. 9

where T _{r is} not significantly changed in the period under consideration, ie does not depend on t. The right side of Equation 9 can be solved by inserting the equations for T _c ι (t).

_ωgbi ( _τ ) = - ^l L (T _r + LT _cl2 ) + ω _gbi (0) Eq. 10

Equations 8 and 9 connect two conditions with the time profile of the engine torque T _e . For T _e (t), an arbitrary approach can now be chosen, which depends on exactly two parameters a and b still to be determined. A time course can preferably be selected in which t occurs up to the second power. In addition, it can also be required that T _e is continuous at t = 0:

T _e (t) = T _e (0) + a -t + b -t ² Eq. 1 1

The right side of equation 11 is inserted into the left side of equation 8 and solved for a:

a = - (T _e , _d -T _e (0) - b -τ ² ) Eq. 12

T

The right sides of equations 5, 10 and 11 are inserted into equation 9, integrated and solved for b:

^b - '<?. ₄ + T _e (0) -T _cl2 ) - - J _e - (ω _{≠ i} (τ) - ω _e (0)) Eq. 13 2

Accordingly, the clutch torque T _c ι and the engine torque T _e r can be appropriately controlled using equations 5 and 11. The contained in the equations Quantities can be determined by consecutively evaluating equations 4, 1, 10, 13 and 12.

It can be assumed that the driver's desired torque T _e , d and the driving resistance remain approximately constant during the re-engagement. However, this does not necessarily have to be assumed. The current values of these variables are continuously accessible to the control code. In this way, the target torque T _C | _{2 of} the clutch, which is required to calculate the current clutch torque according to equation 5, are adapted for each interrupt in accordance with the changed values of the driver's desired torque T _e , d and the sum of all moments T _r acting on the drive train. The same can be done with the parameters a and b, which are used to calculate the engine torque T _e .

In the proposed method for controlling the engine torque T _e and the clutch torque T _c ι in a drive train of a vehicle, the procedure described above and shown in FIG. 2 is preferably called once per cycle.

The patent claims submitted with the application are proposals for formulation without prejudice for the achievement of further patent protection. The applicant reserves the right to claim further combinations of features previously only disclosed in the description and / or drawings.

Back-references used in subclaims indicate the further development of the subject matter of the main claim by the features of the respective subclaim; they are not to be understood as a waiver of the achievement of independent, objective protection for the combinations of features of the related subclaims.

The applicant retains the fact that the subjects of the subclaims can form independent inventions with regard to the state of the art on the priority date to make them the subject of independent claims or declarations of division. They can also contain independent inventions, one of which

Objects of the preceding subclaims have an independent design.

The exemplary embodiments are not to be understood as a restriction of the invention. Rather, numerous changes and modifications are possible within the scope of the present disclosure, in particular those variants, elements and combinations and / or materials which, for example, by combining or modifying individuals in conjunction with those described in the general description and embodiments and the claims and features or elements or procedural steps contained in the drawings can be taken by the person skilled in the art with regard to the solution of the task and, through combinable features, lead to a new object or to new procedural steps or procedural step sequences, also insofar as they involve manufacturing, testing and working methods affect.

Claims

claims

1. A method for controlling an engine torque and a clutch torque in a drive train of a vehicle with a transmission and an engine after a gear change, characterized in that the clutch torque (T _C |) is increased to a predetermined value, and at the same time the engine torque (T _e ) is controlled such that the slip on the clutch is reduced.

2. The method according to claim 1, characterized in that the clutch torque (T _c ι) increases monotonically from a clutch torque directly after engaging the gear

(Value 0) is increased to a predetermined value which corresponds to the clutch torque (Tcl ₂ ) immediately after the transition to sticking.

3. The method according to claim 2, characterized in that the value of the clutch torque (T _C | ₂ ) is calculated by the following equation

4. The method according to any one of the preceding claims, characterized in that the slip on the clutch is reduced by controlling the engine torque (T _e ) exactly when the clutch torque reaches the value (T _c i ₂ ) and / or the engine torque ( T _e ) corresponds to the driver's desired torque again from this point in time.

5. The method according to any one of the preceding claims, characterized in that the engine speed for controlling the engine torque (T _e ) by changing the

Coupling torque (T _c ι) is regulated.

6. The method according to claim 4, characterized in that the clutch torque (T _c ι) is monotonously increased during the re-engagement.

7. The method according to any one of the preceding claims, characterized in that when the clutch is stuck, the equation of motion of the motor by the following Equation is given:

I _e -ώ _e = T _e -r _cl

8. The method according to any one of the preceding claims, characterized in that when the clutch is ^{stuck, the} equation of motion of the vehicle is given by the following equation: ^ώ ₈ gbi

J „- T _r + i -

9. The method according to any one of the preceding claims, characterized in that the sum of all moments acting on the drive train (T _r ) by the following

Equation is calculated:

10. Control device for a drive train of a vehicle with an engine and a transmission coupled via at least one clutch, in particular for

Carrying out the method according to one of claims 1 to 9, characterized in that at least one engine control unit and at least one transmission control unit are provided, which control the engine torque (T _Θ ) and the clutch torque (T _c ι) in such a way that after a gear change the most steady possible Torque build-up is provided.