DE4011850B4 - A method of controlling an automated friction clutch operative between an engine and a transmission - Google Patents

Abstract

method for controlling one between an engine and a transmission effective automated friction clutch, wherein a control intervention point the friction clutch depending can be determined by a torque measurement carried out within the drive train is by the friction clutch from a disengaged position while standing Vehicle is closed to a position, while a Moment introduced into the transmission input shaft, but this moment is less than that by which the vehicle would be moved, and upon reaching this predetermined in its size moment the corresponding position determined as the value for the control intervention point and supplied to a memory is, characterized in that then the friction clutch up to a not fully disengaged state of the friction clutch corresponding waiting position opened becomes.

Description

The The invention relates to a method for controlling a between a Propulsion machine and a transmission effective automated friction clutch according to the generic term of claim 1.

Essential for the function of a friction clutch is the setting of a gripping or regulating engagement point at which a clutch begins to transmit torque. The DE 32 18 933 C2 discloses the detection of a contact point of two frictionally engageable clutch plates as follows: first, it is ensured that one clutch disc sets the other clutch disc in rotation, then the two clutch plates are removed from each other so that no acceleration of one clutch disc by the other more, finally is determined at a re-merging the clutch discs until an alignment of the two clutch disc speeds, the final point of contact.

The DE 31 25 923 A1 discloses a method of determining the grip point of a clutch actuated by a servomotor. Here, the clutch is moved while detecting the clutch travel in the closing direction until the engine speed drops. In this coupling path is closed to the gripping point.

Of the present invention had the object of providing a method create, with the optimum driving comfort, a fuel-efficient Driving, optimum acceleration, gentle driving and Long life of the vehicle, in particular the clutch achievable are.

The The object is solved by the features of claim 1.

This is according to the invention furthermore achieved in that at least for the starting process, a control intervention point the clutch depending on a torque measurement carried out within the drive train and / or an angle measurement can be determined by the coupling of a disengaged Position and with gear engaged and stationary vehicle with defined Speed is closed up to a position at which Although a moment initiated, this moment is less than the one by which the vehicle would be moved and one upon reaching one certain moments and / or a certain angle corresponding Value, e.g. B. the way or location of the clutch operation, determined and a Memory is supplied, whereupon the clutch is at least partially reopened and up to a defined waiting position at which the clutch no moment or only a very low drag torque transmits.

In addition, at least for the Starting operation, a control intervention point of the clutch in response to a Gradient determination on rotatable components of the drive train Determined by the clutch from a disengaged position and not pickled gear and stationary vehicle at a defined speed is closed to a position at which the transmission input shaft Although driven, but remains below the engine idle speed, and on reaching a certain state, as in a determined gradient value and a state-dependent value, as the way or location of the clutch operation, determined and a Memory supplied be, after which the clutch, at least partially, is opened again in a waiting position, in which the clutch no or only transmits a very low drag torque.

Also can that in the actuation system, which may be hydraulically and / or pneumatically formed, pending Pressure instead of the way or place of the clutch operation or additionally determined to this way or place and held in the memory become.

exemplary Embodiments are contained in the subclaims 2 to 5.

Based on 1 and 2 , Showing:

1 the schematic structure of a vehicle drive with a device according to the invention and

2 the schematic structure of a hydraulic adjusting device, which in the device according to 1 is used.

In the 1 illustrated device 1 for driving a motor vehicle includes a motor 2 that has a clutch 3 with the gearbox 4 is positively connected. The gear 4 is about a powertrain 5 with the drive wheels 6 connected the motor vehicle. The friction clutch 3 is via an actuating mechanism 7 , which may comprise a release bearing and an attacking fork, on and disengageable. The operating mechanism 7 is via an actuator in the form of a hydraulic cylinder 8th actuated. The cylinder 8th is over a line 9 with a hydraulic adjusting device, such as a hydraulic actuator 10 , connected, which in 2 is shown in the basic structure.

For controlling the frictional engagement of the clutch 3 is an electronic unit 11 provided, which comprises at least one processor or computer and which regulate the engagement of the clutch 3 required sizes processed to over the hydraulic actuator 10 to regulate a corresponding clutch engagement.

From the electronic unit 11 the sizes are speed of the engine 2 , Speed of the transmission input shaft 12 , Position of the cylinder 8th and position of the throttle 13 (and, if necessary, other engine characteristics such as operating temperature, air temperature, exhaust gas, fuel) recorded.

The electronics unit 11 will be used in conjunction with the in 3 illustrated block diagram explained.

The engine speed is via a sensor 14 determines, for example, the teeth 15 that on the flywheel of the engine 2 scanned starting sprocket.

The transmission speed is via a sensor 16 determines the teeth 17 one on the transmission input shaft 12 scans provided gear.

The position of the fuel supply device or the throttle valve 13 is via a sensor, like a potentiometer 18 , determined.

The driving or accelerator pedal 19 is in the present embodiment with the fuel supply device 13 not mechanically coupled, but via an adjusting device, such as a control loop 20 , which from the electronics unit 11 is controlled and has an electric servomotor.

For gear recognition is on the shift lever 21 a precaution 22 , which may additionally comprise a switching intention detection provided.

By the in the precaution 22 integrable switching intention recognition, becomes the electronic unit 11 Reported if you have the shifter 21 actually moving in the direction where the next logical next course is. If the lever is moved in the wrong direction, this may be done on the electronics unit 11 have no influence, that is the clutch 3 will only open when the shift lever 21 is pressed in the right direction. An actuation of the shift lever 21 in a non-logical direction, that is, from the electronics unit 11 not recognized as switching intent.

To determine the Kupplungsbetätigungsweges or the clutch engagement state is a precaution to travel measurement (transducer), for example, a potentiometer 23 , provided, which the path or the position of the piston of the actuator 8th detected and a corresponding electrical variable to the electronics unit 11 reports.

Instead of sensing the path or position of a clutch actuator, the pressure prevailing in the hydraulic actuator could also be detected by the electronic unit 11 be processed accordingly. For this purpose, only instead of the transducer 23 a pressure gauge required z. B. in the hydraulic actuator 8th detected pressure and converted into an appropriate size, which to the electronic unit 11 is reported. For many applications, it may also be advantageous if both a distance measurement and a pressure measurement takes place, wherein the pressure measurement can be used in a particularly advantageous manner for the regulation of the slip in the clutch, as for this adjustment in part only very small ways of be returned to the actuator.

In the 2 shown schematically, hydraulic adjusting device 10 has one via an electric motor 25 drivable hydraulic pump 26 that with an oil reservoir 27 communicates and via a valve block 28 the hydraulic cylinder 8th can apply. In the valve block 28 is an electromagnetically actuated 3/3 control valve 29 integrated with return spring, which from the electronic unit 11 can be controlled. The control valve 29 acts as a volume proportional valve, which means that the valve spool is displaced in response to the magnitude reported by the electronic unit, thereby varying the flow area accordingly. As an alternative, a volume-proportional 4/4 valve or a control valve, which is controlled via a pulse width modulation, could also be used.

Between the pump 26 and the control valve 29 is a filter 30 , a check valve 31 , the engine 25 If required, switch on and off pressure switch 32 and a pressure accumulator 33 intended.

The pressure accumulator can be dimensioned such that when starting the motor vehicle at least a first disengagement without energy supply is possible, so that then no special engine 25 for the pump 26 is required. currency rend the operation of the internal combustion engine 2 can the memory 33 be powered by a driven by the internal combustion engine pump, as operated by the power steering.

Below is the operation of the unit 1 according to the 1 and 2 described in more detail.

At startup of the internal combustion engine 2 So when the vehicle is stationary, as soon as the ignition contact is closed, the control valve 29 so controlled that over the hydraulic cylinder 8th the coupling 3 through the energy of the pressure accumulator 33 stock is completely disengaged. Once the engine 2 is cranked and rotates at idle speed, so no gear is engaged, the clutch 3 closed from its disengaged position at a defined speed to a position at which the transmission input shaft 12 Although driven, it remains below the engine idle speed and a certain gradient, such as speed gradient or angular acceleration gradient, from the sensor 16 to the electronic unit 11 is reported. On the basis of the measured gradient, it is now possible to determine the engagement distance of the clutch which has been reached until this gradient is determined 3 be corrected to obtain a control intervention point. This control intervention point corresponds to the location of the actuation path of the friction clutch 3 , to which a quick engagement process takes place. When exceeding this control intervention point in the direction of engagement of the clutch 3 there is a controlled engagement. The detection of the control intervention point is required to largely eliminate the influence of manufacturing tolerances and thus to achieve optimum clutch operation for each motor vehicle. Due to the gradient gradient up to the limit gradient, the engagement path of the clutch that has traveled back to this limit gradient can be achieved 3 be corrected so that in a flat course of the gradient increase a greater correction in the disengagement of the clutch 3 takes place as in a steep gradient gradient. A flat course of the gradient increase may be due, for example, to a clutch disc with a greater axial impact, so that the control engagement point is used earlier when engaging the clutch earlier than is achieved with a disc with little lateral impact.

As soon as the driver inserts the first, possibly the second or the reverse gear, the clutch becomes 3 via the hydraulic adjusting device 10 closed at high speed to the control intervention point. If now the driver is the gas pedal 19 pressed, can be one in the processor of the electronic unit 11 stored map one of the position of the throttle 13 determined dependent speed and are formed by adding the current idle speed, a starting speed. This starting speed is via the throttle 13 operating control arrangement 20 set. The controlled closing of the clutch 3 Now takes place such that at a defined accelerator pedal position, the starting speed remains virtually constant over the entire engagement. As the optimum speed for starting that speed can be stored at which the engine 2 for a given throttle position gives the maximum torque. By such closing of the friction clutch 3 a smooth, smooth start with optimum torque is possible, with a stalling of the engine is virtually eliminated.

By consideration the idling speed when determining the starting speed, the weather-related influences considered For example, since the idling speed depends on the cooling water temperature.

The controlled closing of the clutch 3 This can be done until a desired slip speed is reached or until that of the clutch 3 transferable moment at least approximately just that of the engine 2 delivered torque corresponds. As an alternative, the clutch could 3 also be completely closed.

When attempting to start in other than the designated gears, the clutch remains 3 opened and the throttle 13 can from the regulation precaution 20 be kept in a closed state, to prevent accidental engine rotation.

Claims (5)

A method of controlling an automated friction clutch operative between an engine and a transmission, wherein a control engagement point of the friction clutch is determinable in response to a torque measurement performed within the powertrain by closing the friction clutch from a disengaged position when the vehicle is stationary to a position where Although a moment introduced into the transmission input shaft, but this moment is less than that by which the vehicle would be moved, and upon reaching this predetermined in size torque, the corresponding position is determined as a value for the control intervention point and fed to a memory, characterized that then the friction clutch is opened to a non-fully disengaged state of the friction clutch corresponding waiting position. Method according to claim 1, characterized in that that the moment measurement by means of an angle measurement between a Input and an output element of the friction clutch takes place. Method according to claim 1 or 2, characterized that the moment measurement by means of a gradient determination at least a rotating part of the drive train takes place. Method according to one of claims 1 to 3, characterized that a stored value by a currently determined value is corrected. Method according to claim 3, characterized the gradient is determined from the rotational speed of the transmission input shaft becomes.