KR101989352B1 - Method for controlling an automated friction clutch in a drive train of a motor vehicle during a start-up procedure - Google Patents

Abstract

The present invention relates to a method of controlling an automatic friction clutch in a drive train of an automobile during a starting procedure, comprising: an internal combustion engine and a transmission controlled by a driver's requested torque using a gas pedal; The control variable for the clutch torque that can be transmitted through the friction clutch is set by the target rotation speed in such a manner that the ratio between the rotation speed and the transmission input rotation speed of the transmission is adapted until the engine rotation speed and the transmission input rotation speed coincide with each other Is executed according to the engine speed controller. To achieve a smooth transition of the friction clutch from slip to engagement during the starting procedure according to the starting dictionary state, the target rotation speed is corrected using a correction variable that depends on the slip variation of the friction clutch.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method of controlling an automatic friction clutch in a drive train of a vehicle during a starting procedure,

The present invention relates to a method of controlling an automatic friction clutch in a drive train of an automobile during a starting procedure and relies on an internal combustion engine, a transmission, and an engine speed controller controlled using a gas pedal for a driver required torque, The rotational speed controller controls the ratio of the engine rotational speed of the internal combustion engine to the transmission input rotational speed of the transmission in accordance with the gas pedal position of the gas pedal until the engine rotational speed and the transmission input rotational speed coincide with each other, Lt; RTI ID = 0.0 > clutch torque < / RTI >

BACKGROUND ART Automobiles with an internal combustion engine and a drive train including a transmission such as, for example, a manual transmission, an automatic transmission, a continuously variable transmission (CVT), and a double clutch transmission are known from mass production applications and the double clutch transmission comprises two independent And an automatic friction clutch disposed between the internal combustion engine and the transmission or the partial transmission. At this time, when starting the automobile of this type, the rotation speed difference between the driving wheels that are stopped or rotated at a low rotation speed is adjusted to the internal combustion engine rotating at least at the idling rotation speed, and a comfortable starting procedure is performed without turning off the internal combustion engine Slip control of the friction clutch is necessary.

Here, as is known from, for example, document DE 198 37 816 A1, since the internal combustion engine provides little output in the case of a low rotational speed and a large amount of frictional force in the friction clutch in the case of a high rotational speed, And is maintained within a predetermined rotational speed range through driving. The slip of the friction clutch due to the increase of the rotational speed of the automobile, that is, the deviation of the engine and the transmission input rotational speed, decreases until the switching between the slip and the attachment of the friction clutch is achieved. Such a transition may be considered non-operational friendly due to excitation of so-called jerking vibrations in the drive train, wherein the more the angular acceleration of the engine rotational speed and the transmission input rotational speed at such a transition is, It is not operational friendly.

Here, an engine speed controller designed to control the internal combustion engine at a constant target rotational speed is provided in the control. In order to adjust the engine angular acceleration to the transmission input angular acceleration, a constant increase of the target rotational speed is made by the compensatable characteristic diagram, and the characteristic diagram is changed according to the ratio of the transmission pedal angle and the transmission input rotational speed to the engine rotational speed The target rotation speed rise is specified in advance. At this time, the ratio of the transmission input rotational speed to the engine rotational speed is regarded as a scale for advancing the starting. Here, the increase of the target rotation speed does not directly cause the rotation speed change, but rounds the transition between the sliding step and the attachment step of the friction clutch. Rather, a deviation between the target rotational speed of the internal combustion engine and the current rotational speed must be formed so that the control deviation at the target rotational speed is first generated to take the specific angular acceleration, and to take the desired angular acceleration for rounding. These control deviations are ideally designed for so-called standard starting only under the pre-defined requirements. Unpredictable difficulties arise when adjusting the starting procedure, for example, at varying travel pedal angles, in starting procedures with different loads, and in various starting conditions, such as cars rolling or stopping at different slopes.

It is an object of the present invention to provide an improved example of a control previously known as this type of automatic friction clutches during a starting procedure in which various starting states can be overcome without loss of comfort using a consistent starting procedure .

This problem is solved by a method for controlling an automatic friction clutch in a drive train of an automobile during a starting procedure, comprising the steps of: controlling an internal combustion engine and a transmission controlled to a driver's requested torque using a gas pedal; The control variable for the clutch torque that can be transmitted through the friction clutch is set to the target rotation speed in such a manner that the ratio between the engine rotation speed of the internal combustion engine and the transmission input rotation speed of the transmission is adapted until the engine rotation speed coincides with the transmission input rotation speed. The target rotational speed is corrected using a correction variable according to the slip variation of the friction clutch. The target rotational speed can be detected without reserving the control variable by introducing a correction variable that takes into account the slip variation of the friction clutch and thereby the individual angular accelerations of the transmission input side such as the internal combustion engine and the transmission input shaft such as the crankshaft axis, Therefore, it is not important to distinguish between the set rotation speed of the internal combustion engine and the current rotation speed for the control procedure of the friction clutch.

Here, the slip change degree can be detected from the deviation between the engine angular acceleration of the internal combustion engine and the transmission input angular acceleration of the transmission. Here, the control process of the engine speed controller during the starting procedure may be divided into a plurality of control intervals, and the correction variable at the intervals is detected from the target slip variances detected from the current clutch slip and the transmission input angular acceleration, . At this time, the current target rotation speed can be formed from the preceding target rotation speed and the correction variable detected at the current control interval, respectively. It has been shown that preferably the slip variability is specified as negative. The target rotational speed currently corrected by the correction variable is set to a value that is not originally corrected so that the minimum rotational speed of the internal combustion engine is guaranteed and the engine torque does not control the internal combustion engine with ranges of rotational speeds too low for start- Respectively.

The detection of the target slip variation corresponding to the formation of the correction variable or the formation of the correction variable can be detected using the characteristic diagram from the current clutch slip. In particular, in the detection of the above-mentioned type of target slip variability in time critical dynamic control situations, the target slip variance can alternatively be predicted from the current clutch slip by extrapolation of the preceding clutch slip using the currently detected slip variance have. Also, the current clutch slip can be predicted by extrapolation of the preceding clutch slip using the currently detected slip gradient.

The control variable for the clutch torque transmittable through the friction clutch is detected using the characteristic diagram from at least the corrected target rotational speed, and the control parameter for the clutch torque, which can alternatively or additionally be transmitted through the friction clutch, Can be detected from at least the currently detected engine target rotation speed change degree.

The present invention is described in more detail by the embodiment shown in Figs.

1 is a partial view of a basic circuit diagram of an engine speed controller for forming correction parameters.
2 is a graph for showing a starting procedure having a target rotation speed of the internal combustion engine corrected using a correction parameter.
FIG. 3 is a graph showing the engine rotation speed and the transmission input rotation speed during starting of the vehicle at the ascending slope. FIG.
4 is a graph showing the engine rotational speed and the transmission input rotational speed during starting of the vehicle when the vehicle is downhill.

1 schematically shows an enlarged portion 1 of an engine speed controller in the form of an engine speed controller, as compared to the control of an automatic friction clutch, for example as known from document DE 198 37 816 A1. First, the target target slip change degree (Ndot_SI_target) is detected in the form of a deviation between the engine angular acceleration and the transmission input angular acceleration. For this purpose, for example, rotational speeds dependent on the time of the crankshaft axis of the internal combustion engine and the transmission input shaft are measured using the corresponding sensors. Here, the target slip change degree (Ndot_SI_target) is derived from the characteristic map (KL_SI_target) according to the current clutch slip (N_SI_current) of the friction clutch. To avoid too long response times in the case of detection of the target slip change degree (Ndot_SI_target) by the degree of characteristic (KL_SI_target) in very dynamic situations of the starting control, alternatively, the current clutch slip N_SI _ Current) can be extrapolated to the current target slip variance (Ndot_SI_target), so that slip for the identifiable time interval can be predicted in this manner.

An original engine speed controller for controlling a constant target rotation speed (N_Mo_target_minimum) and a target rotation speed (N_Mo_target_value) corrected for the slip change in the extended portion (1) or control intervals dt) of the target rotation speed (N_Mo_target_sound) is changed without failure between the continuously updated target rotation speed (N_Mo_target_sound) using the detected correction variables, the detection of the current target rotation speed (N_Mo_target_sound) is performed as follows.

A change in the target engine speed change degree (Ndot_Mo_Go_VS) per control interval dt is derived from the current transmission input angular acceleration (Ndot_IPS_current) and the target slip change degree (Ndot_SI_target). This change is added to the preceding target rotation speed (N_Mo_target_sphere) of the internal combustion engine. In order to ensure the lowest engine rotational speed, the obtained target rotational speed is limited downward to the "normal" target rotational speed (N_Mo_target_num). When this restriction is achieved, the set engine angular acceleration such as the target engine rotational speed variation degree (Ndot_Mo_Go_VS) is also corrected, and the target engine rotational speed variation degree is corrected to the current target rotational speed N_Mo_Go It is adjusted to the same set rotation speed curve. Further, the engine target rotation speed change degree (Ndot_Mo_target_shift) is directly supplied to the engine rotation speed controller, and is added to the set engine angular acceleration in order to prevent the angular acceleration from being zero. On the other hand, the engine target rotational speed change degree (Ndot_Mo_target_shift) can be directly converted to clutch torque to pre-control the friction clutch and can be added to the total clutch setting torque at a rate that can be specified. Thereby, a direct influence of the engine target rotation speed change degree (Ndot_Mo_target_shift) at the clutch torque can be simultaneously achieved or the engine target rotation speed change degree can be considered in the engine rotation speed controller, The control of the controller is interrupted by the engine rotation speed controller (Ndot_Mo_target_signal) or the control of the controller is assisted by the engine rotation speed controller.

Figure 2 shows a graph 2 formed from a partial graph I and a partial graph II. The partial graph (I) shows the rotational speed curves of the driving train over time during the starting procedure, and the partial graph (II) shows the corresponding rotational speed variation curves according to the time. Concretely, the curve 3 shown by the broken line in the partial graph I indicates the corrected target rotation speed N_Mo_target_sound in FIG. 1 as the rotation speed increase curve along the transmission input shaft rotation speed curve 5 4). ≪ / RTI > Since the target rotation speed (N_Mo_target_shift) is made according to the correction variable in the form of the slip variability of the friction clutch, unlike the control of the engine speed controller of the conventional system, the current engine rotation speed curve It immediately follows the rotational speed increasing curve 4 without the necessary control deviation that can be calculated for standard starting. Here, the set rotation speed and the current rotation speed continue without any necessary deviation, which on the one hand simplifies the adjustment and on the other hand enables a more flexible control strategy.

The partial graph II shows the transmission rotation speed variation curve 7 of the internal combustion engine, the current engine rotation speed variation curve 8 and the transmission input rotation speed variation curve 9 set from the friction clutch. The target rotational speed variation at the turning point kp of the partial lines 7 and 12 used for the engine rotational speed controller follows the conventional partial line 7 while the left side of the turning point kp has the partial- The target rotational speed at which the slip degree of change of the partial line 12 of the set engine rotational speed variation curve 10 formed from the engine 11 and 12 is controlled is prescribed in advance. As soon as the set revolution speed change curve 7 and the set engine revolution speed change curve 10 are cut off at the changeover point kp, the set engine revolution speed change curve 10 having the partial lines 11, The limited set rotational speed variation degree first affects the engine speed controller at the partial line 12, while causing the engine speed controller to increase the target rotational speed of the internal combustion engine. In order to clarify the control behavior of the conventional system, a dot-dash line 14 is displayed on the right side of the switching point kp, and accordingly, when the rotation speed is low, a correspondingly low rotation speed change- Respectively.

3 and 4 illustrate engine speed curves 15 and 15a and transmission input rotational speed curves 16 and 15 in the steep downhill slope (FIG. 3) and the steep uphill slope (FIG. 4) The starting procedures performed using the control according to the present invention are shown by graphs 13 and 14 for time t with time points 16a and 16a. Unlike the conventional engine speed controller, when the rotational speed increase is required by using the engine speed controller according to the present invention by comparing the rotational speed variation of the crankshaft axis and the transmission input shaft. Under conventional control, the rotational speed increase can be started at the same transmission input rotational speed in both states, through which one time is too late and too little, and one time is too early and too strong.

1 Part of the basic circuit diagram of the engine speed controller
2 graph
3 curves
4 Rotation speed increase curve
5 Transmission input shaft curve
6 Current engine speed curve
7 Set rotation speed change curve
8 Current engine speed change curve
9 Transmission input speed change curve
10 Setting engine speed change curve
11 partial lines
12 partial lines
13 Graph
14 graph
15 Engine speed curve
15a Engine speed curve
16 Transmission input speed curve
16a transmission input speed curve
dt control interval
KL_SI_ target characteristic diagram
KP turning point
L line
Ndot_IPS_ Current Transmission Input Angular Acceleration
Ndot_Mo_ Goal_ New engine target rotation speed change degree
Ndot_Mo_target_VS The target engine speed change rate from the travel strategy
Ndot_SI_ target target slip change
N_Mo_ Goal _ Lowest preceding target rotation speed
N_Mo_ Goal_ New updated target rotation speed
N_SI_ Current clutch slip
t time
Ι partial graph
Ⅱ partial graph

Claims (9)

A method of controlling an automatic friction clutch in a drive train of an automobile during a starting procedure, the method comprising an internal combustion engine and a transmission controlled by a driver's requested torque using a gas pedal, and an engine rotational speed controller, The control variable for the clutch torque that can be transmitted through the friction clutch is set to the target rotation speed in such a manner that the ratio between the engine rotation speed of the internal combustion engine and the transmission input rotation speed of the transmission is adapted until the engine rotation speed coincides with the transmission input rotation speed. A method of controlling an automatic friction clutch in a drive train of an automobile during a starting procedure, which is executed in accordance with an engine rotational speed controller set by a speed,
Characterized in that the target rotational speed is corrected using a correction variable according to the slip variation of the friction clutch. 2. A method as claimed in claim 1, characterized in that a slip change is detected from a deviation between the engine angular acceleration of the internal combustion engine and the transmission input angular acceleration of the transmission. 3. A method as claimed in claim 1 or 2, characterized in that the correction variables are respectively detected from the target slip change detected from the current clutch slip and the transmission input angular acceleration through the repeated control intervals, Of the friction clutch. The method according to claim 3, characterized in that the current target rotational speed is formed from a preceding target rotational speed and a correction variable detected at the current control interval, respectively, and a method for controlling an automatic friction clutch in a drive train of an automobile during a starting procedure . 3. A method as claimed in claim 1 or 2, characterized in that the current target rotational speed is limited to the original uncorrected target rotational speed. 4. The method according to claim 3, characterized in that the target slip variance affecting the correction variable is detected from the current clutch slip using the characteristic map. 4. The method of claim 3, wherein the current clutch slip is predicted by extrapolation of the preceding clutch slip using the currently detected slip transition. 3. A drive train as claimed in claim 1 or 2, characterized in that the control variable for the clutch torque transmittable through the friction clutch is detected from at least the corrected target rotation speed using the characteristic map. A method of controlling a friction clutch. 3. A method as claimed in claim 1 or 2, characterized in that the control variables for the clutch torque transmittable through the friction clutch are detected from at least the currently detected engine target rotational speed variance using the characteristic map. A method for controlling an automatic friction clutch in a drive train.

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