WO2003016085A1 - Method for regulating an automated clutching on a motor vehicle - Google Patents

Abstract

The invention relates to a motor vehicle and a method for regulating an automated clutching on a motor vehicle driven by an engine, by means of a control device, during an acceleration process. The engine accelerates the motor vehicle until a wheelslip of the driven wheels relative to the ground is detected by the control device, whereupon a control command is sent to the clutch from the control device which retracts the clutch so far that the wheelslip is reduced to a small residual value.

Description

 Method for regulating an automated clutch of a motor vehicle

The invention relates to a method for regulating an automated clutch of a motor vehicle driven by an engine by means of a control unit during an acceleration process.

Such a method is described and shown in DE OS 4011850. The known method allows the clutch to be automatically controlled for different operating states, such as starting, shifting, driving, accelerating, braking, reversing, parking or the like, or of transitions between individual operating states, in such a way that they connect to the for each operating state the required times.

The invention is based on the object of designing a special operating state, namely the acceleration process, by controlling the automated clutch in such a way that the driver can perceive a particularly favorable driving behavior of the motor vehicle. According to the invention, this occurs in that the engine accelerates the motor vehicle up to a wheel slip of the driven wheels detected by the control device relative to the ground, whereupon the control device transmits a control command to the clutch so far that the wheel slip is reduced to a small residual value ,

Due to this control of the automated clutch, the power delivered by the engine is initially fully usable, but without the risk of the driven wheels coming into the state of pronounced wheel slip due to excessive torque given off by the engine, in which the driver easily loses control of his motor vehicle. In the method according to the invention, a slight wheel slip is consciously accepted, namely the small residual value of wheel slip mentioned, which is normally not perceived by the driver due to its insignificance, but is still measurable and can therefore be used to control the automated clutch , In the above-described operation, the clutch comes into a state in which clutch slip exists, by which the torque transmitted to the wheels is reduced accordingly. In order to reduce the associated load on the clutch, one can expediently influence the control device by issuing the control command in such a way that it controls the engine in the sense of a reduction in the engine torque.

The transmission of control commands from the control unit to the clutch is advantageously limited to a defined period of time after which the clutch engages. This ensures that the clutch is only brought into a state in which clutch slip exists for this defined period of time. At the same time, there is the effect that the clutch slip, which loads the clutch, is limited to the defined period.

The method described above has a particularly favorable effect if the acceleration process is the kick-down process. In the case of kick-down, wheel slip occurs particularly frequently and is largely avoided by the method according to the invention.

The method according to the invention has a particularly favorable effect when the vehicle is starting up, because the acceleration process can then take place with the clutch disengaged until the engine speed reaches a speed value in a range in which the loaded engine delivers its maximum torque, whereupon the control unit triggers the clutch engagement. In this process, a higher speed with which a quick start can be achieved is achieved particularly quickly, which is of particular importance for certain situations when using a motor vehicle, for. B. when entering from a stand in a busy highway.

There are various known methods for determining wheel slip. For example, wheel slip can be determined using the sensors specified in an anti-lock braking system. Another method is to take advantage of the sensors that are provided to determine the wheel slip in a driving stability system. The known driving stability system influences the braking system of the motor vehicle and its engine in such a way that wheel slip is largely avoided. With regard to the function of the driving stability system, it should be said that such electronic stability systems are generally known in motor vehicles, as has become known, for example, from DE publication VDI Report 1224. The function of anti-lock braking systems (ABS) is also generally known and already classified in the International Patent Classification (IPC).

The device shown in the figure for driving a motor vehicle comprises a motor 2 which can be non-positively connected to the transmission 4 via a coupling 3. The transmission 4 is connected to the drive wheels 6 of the motor vehicle via a drive train 5. Sensors 25 are attached to the drive wheels 6 and the non-driven wheels 24 of the motor vehicle, from which the respective wheel speed is measured and passed on as in the manner described below. The clutch 3 can be engaged and disengaged via an actuating mechanism 7, which can include a release bearing and a fork acting thereon. The actuating mechanism 7 is actuated via a hydraulic cylinder 8. The cylinder 8 is connected via a line 9 to a hydraulic adjusting device, such as a hydraulic actuator 10.

To control the engagement of the clutch 3, a control unit 11 is provided, which comprises at least one processor or computer and processes the quantities required for controlling the engagement of the clutch 3 in order to regulate a corresponding clutch engagement via the hydraulic actuator 10.

The control unit 11 records the values of the speed of the engine 2, the speed of the transmission input shaft 12, the position of the cylinder 8 and the position of the throttle valve 13 (and, if necessary, further engine parameters such as operating temperature, air temperature, exhaust gas, fuel).

The engine speed is determined by a sensor 14 which, for example, scans the teeth 15 of the starter ring gear provided on the flywheel of the engine 2. The transmission speed is determined by a sensor 16 which scans the teeth 17 of a gearwheel provided on the transmission input shaft 12. The position of the fuel supply device or the throttle valve 13 is determined by a sensor, such as a potentiometer 18. In the present exemplary embodiment, the accelerator or accelerator pedal 19 is not mechanically coupled to the fuel supply device 13, but via an actuating device, such as a control circuit 20, which is controlled by the control unit 11 and has an electric servomotor.

A precaution 22 is provided on the gearshift lever 21 for gear detection, which may additionally include a shift intention detection.

To determine the clutch actuation path or the clutch engagement state, provision is made for distance measurement (displacement sensor), for example a potentiometer 23, which detects the path or the position of the piston of the actuator 8 and reports a corresponding variable to the control unit 11.

The sensors 25 emit their signals to the device 26 which, depending on the equipment of the motor vehicle in question, can belong to an anti-lock braking system or to a driving stability system (see above). From this device, the signals received by the sensors 25 are processed and fed via line 28 to the control unit 11, in which a wheel slip is then determined either in the presence of an anti-lock braking system or a driving stability system, which then leads to the purpose of the method according to the invention, which To transmit clutch 3 from control unit 11 a control command by which clutch 3 is disengaged. On the basis of this control command, clutch 3 is disengaged to such an extent that the wheel slip determined is reduced to a small residual value, which is then further evaluated by sensors 25 and the device. When the control command from the control unit 11 to the clutch 3 is issued, a signal is also transmitted to the control circuit 20, which acts in the sense of reducing the engine torque by the control circuit 20 actuating the throttle valve 13 accordingly.

The control command transmission from control unit 11 to clutch 3 can, as already above. are limited to a defined period of time, which is brought about by a timer contained in the control unit 11. As long as the control command transmission continues, the clutch 3 remains disengaged so far that the wheel slip is limited to a small reduced residual value. After the defined period has elapsed, the clutch is released

3 fully indented.

In the exemplary embodiment shown, the acceleration process takes place with the clutch 3 disengaged, that is to say with the engine under load. This occurs until the engine speed measured via the sensor 14 reaches a speed value in a range in which the loaded engine 2 normally delivers its maximum torque. This maximum torque is known due to the engine characteristic. If the mentioned speed value is reached, the control unit 11 triggers the engagement of the clutch 3, since the control unit 11 is informed of the speed value by the sensor 14.

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.

Since the subjects of the subclaims can form their own and independent inventions with regard to the prior art on the priority date, the applicant reserves the right to make them the subject of independent claims or declarations of division. They can furthermore also contain independent inventions which have a design which is independent of the objects of the preceding subclaims.

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, can be combined or modified by individuals in conjunction with the general description and embodiments described in the Features or elements or process steps described in the claims and contained in the drawings can be taken by the person skilled in the art with regard to the solution of the task and, by means of combinable features, lead to a new object or to new process steps or process step sequences, also insofar as they produce, Test and work procedures concern.

Claims

claims 1. A method for regulating an automated clutch of a motor vehicle driven by a motor by means of a control device during an acceleration process, characterized in that the motor accelerates the motor vehicle up to a wheel slip of the driven wheels detected by the control device relative to the ground, whereupon the clutch from Control unit a control command disengaging the clutch so far that the wheel slip is reduced to a small residual value. 2. The method in particular according to claim 1, characterized in that with the delivery of the control command, the control device controls the engine in the sense of a reduction in the engine torque. 3. The method in particular according to claim 1 or 2, characterized in that the control command transmission from the control unit to the clutch is limited to a defined period of time after which the clutch engages. 4. The method in particular according to one of claims 1-3, characterized in that the acceleration process is carried out as a kick-down. 5. The method in particular according to one of claims 1-4, characterized in that the acceleration process takes place with the clutch disengaged until the engine speed reaches a speed value in a range in which the loaded engine delivers its maximum torque, whereupon the control unit engages the clutch triggers. 6. The method in particular according to one of claims 1-5, characterized in that the wheel slip is determined via the sensors provided in an anti-lock braking system. 7. The method in particular according to one of claims 1-5, characterized in that the wheel slip is determined via the sensors provided in a driving stability system. 8. Motor vehicle with an automated clutch, in which the motor accelerates the motor vehicle up to a wheel slip of the driven wheels detected by the control unit against the ground by means of a control unit during an acceleration process, whereupon the control unit transmits a control command to the clutch so far is that the wheel slip reduces to a small residual value, possibly in connection with one of the preceding claims.