DE10232495A1 - Automatic clutch engagement point regulation method for motor vehicle transmission involves detecting vehicle function parameter and adjusting activation point at preset value of parameter - Google Patents

Abstract

The automatic clutch engagement method for a motor vehicle involves adjusting the engagement point outside a tolerance range and regulating a predetermined number of regulation demands. It involves detecting a vehicle function parameter (32) and adjusting the clutch activation point dependent on a preset value of the parameter. The value is memorized and compared to the tolerance range. Claims include a regulator using the method

Description

The invention relates to a method and a device for self-sufficient Setting the touch point of one contained in a drive train of a vehicle automated clutch.

Automated clutches are not only found because of what they achieve Comfort gain, but also because of possible consumption savings in Motor vehicles increasingly use.

FIG. 2 shows an exemplary block diagram of a drive train of a motor vehicle equipped with an automated clutch. The drive train contains an internal combustion engine 2 , a clutch 4 and a transmission 6 , from which a drive shaft 8 leads to drive wheels, not shown. The transmission 6 is, for example, an automated manual transmission or a conical pulley belt transmission with continuously variable transmission ratio. An actuating device 9 , which can be controlled from a selector device 10 by means of a selector lever 12 via a control device 14 in a manner known per se, serves to actuate or to switch the transmission 6 . It goes without saying that the selection device can also be designed differently, for example as a classic shift lever (H-link) or as a lever with tip positions for shifting up and down. The clutch 4 is, for example, a friction disk clutch of a type known per se with an actuating device 16 which is designed hydraulically, electrically, electrohydraulically or in any other known manner.

Sensors contained in the drive train, such as a pressure sensor 18 for detecting the intake pressure of the engine 2 , a speed sensor 20 for detecting the speed n _{M of} the crankshaft of the engine, a sensor 22 for detecting the position α of an accelerator pedal 24 , and a sensor 28 for detecting the position of the selector lever 12 and a further speed sensor 28 for detecting the speed of the drive shaft 2 are connected to the inputs of the control device 14 .

In the control unit 14 , which contains a microprocessor with associated memories 29 in a manner known per se, maps and programs are stored with which actuators, such as a load actuator 30 for adjusting the load of the motor 2 , the actuating device 16 of the clutch 4 and the actuating device 9 of the transmission 6 and other consumers 31 directly or indirectly driven by the motor, such as a generator, a pump or a heating element, etc., are controlled. The individual actuators can be constructed such that their position is known directly in the control unit 14 , for example as stepper motors, or additional position transmitters, such as a position transmitter 32 for detecting a parameter relevant for the position s _{K of} the clutch, can be provided.

A foot brake sensor 30 a and a hand brake sensor 30 b are also connected to the control unit 14 . A further control unit 34 is connected to the control unit 14 via a data bus 33 , which, for example, controls the vehicle brakes 35 , as is known from anti-lock systems or driving stability systems. The hardware and software division between devices 14 and 34 is adapted to the respective circumstances.

The structure and function of the system described are known per se and are therefore not explained in detail. Depending on the driving request communicated via the accelerator pedal 24 and the desire for a driving program or driving direction communicated via the selector lever 12 , the load actuator 30 , the actuating device 16 and the actuating device 9 are actuated in a mutually coordinated manner as a function of the signals supplied by the sensors, so that results in comfortable and / or economical driving.

For the actuation of the clutch 4, for example, a characteristic curve is stored in a memory of the control device 14 , which defines a desired position of the clutch 4 set by the actuating device 16 as a function of the torque to be transmitted by the clutch 4 in each case. For reasons of control quality, clutch wear and energy consumption of the actuating device, the clutch torque that can be transmitted should only be as large as is absolutely necessary. The required torque to be transmitted results from the driver's request or the position of the accelerator pedal 24 and, for example, the load of the internal combustion engine 2 detected by the sensor 18 and possibly further operating parameters, such as the speed of the engine 2 etc.

The characteristic curve stored in the control unit 14 , which indicates the desired path of an actuator of the clutch moved by the actuating device 16 as a function of the calculated torque to be transmitted, has a decisive influence on comfortable starting and a comfortable handling of the switching process. The characteristic curve changes briefly, for example as a result of temperature changes, and long-term over the course of the life of the clutch, for example as a result of wear. It is therefore constantly updated or adjusted according to various strategies when predetermined operating conditions are present.

Fig. 3 shows an example in detail of an actuating device 16 with hydraulic line.

In a master cylinder 36 filled with hydraulic fluid, a piston 38 works , the shaft 40 of which has an external toothing which meshes with an internal toothing of a toothed wheel 41 , which in turn meshes with the external toothing of a pinion 42 of an electric motor 43 , which is controlled by the control unit 14 ( FIG . is driven 4). The electric motor can be of any suitable type and is controlled, for example, by means of a PWM signal. The electric motor is advantageously a stepping motor. The master cylinder 36 has a sniffer bore 44 , which is connected via a line 45 to an expansion tank (not shown). A line 48 leads from the pressure chamber 46 of the cylinder, which leads to a slave cylinder 50 in which a piston 52 works, which is connected via its piston rod, for example, to the release lever 54 of the clutch, which forms an actuator. The position A, which is generally referred to as the sniffing position, is the position when it is passed over by the piston 38 to the right in accordance with FIG. 4, pressure builds up in the pressure chamber 46 for actuating the clutch.

For determining the position, an incremental position transmitter 32 known in its construction is provided on the gear 41 , for example, which counts the teeth of the gear 41 moving past it and emits corresponding pulses to the control device 14 . The number of these pulses is a direct measure of the displacement of the master piston 38 or, if the master piston 38 is located to the right of the sniffing position A according to FIG. 9, the movement of the release lever 54 .

In a so-called sniffing process, the master piston 38 , advantageously a check valve (not shown) is integrated, so that if the pressure on the left side of the piston 38 opens, it is moved to the left beyond the sniffing position A, which also carries the hydraulic path between the pistons 38 and 52 the line 45 is connected and is depressurized. In this depressurized state of the hydraulic line, the release lever 54 assumes its position corresponding to the fully closed or closed position of the clutch. When the master cylinder 38 is subsequently moved to the right by the electric motor 42 , the release lever 54 is actuated at the moment when the master piston 38 passes over the sniffing position A. This position of the master piston 38 can be detected in a wide variety of ways, the respective count of the position sensor 32 being stored in the control unit 14 as the closed position.

In addition to the closed position of the clutch, precise knowledge of the gripping or Touch point of the clutch is important, that is the position at which the clutch transmits a predetermined, small torque of, for example, 4 Nm. The precise knowledge of the gripping point is important because it when starting and plays a crucial role in shifting. If the clutch over the Is also completely separated. Will the clutch not operated up to the gripping point is a gear change without massive Influencing comfort or even endangering the transmission is not possible and that Vehicle creeps too much.

The gripping or touch point is normally set in that in certain operating states of the drive train, for example when the vehicle is stationary and the brake is applied and the gear is engaged, the clutch is fully opened and then slowly closed, the engine torque being measured. If, during the slow clutch closing, the engine torque; position sensor 32 is read out and its value is stored as the clutch's gripping point, which is achieved in a particularly simple manner with an engine idling control by an actuator of the idling control, for example. The gripping point can thus be approached quickly and serve as an orientation value for carrying out an initial operation or a switching operation. A gripping or touch point adaptation takes about 5 seconds and typically takes place at least once per trip.

Similarly, individual points of the path / torque characteristic of the clutch stored in the control unit can be updated or adapted by determining the clutch torque and reading the associated position of the actuating device or position transmitter 32 and storing it as an updated or adapted new position. The clutch is still slipping when the clutch is engaged with a relatively high clutch torque and the clutch torque is determined by determining the torque of the internal combustion engine, taking into account its speed change and moment of inertia. The clutch characteristic curve, which changes as a result of changing the coefficient of friction of the clutch, can be adapted or adapted in this way.

As explained, the master cylinder moves briefly into its when sniffing Sniffing position back. The clutch is closed completely. On Sniffing process takes about 400 m / sec. and can for example be at a distance of a few minutes.

A problem that arises in practice for vehicles with a automated clutch is the first setting of the touch point at the Commissioning of the vehicle, for example at the end of a Production belt. This is generally done with the help of an external diagnostic system that the vehicle must be plugged in and that the driver via one Prompts dialogue about predetermined actions.

The invention has for its object a simple way to Setting the touch point when starting up the vehicle, for example at its initial start-up after its manufacture or when it is renewed Commissioning after extensive repairs on the drive train create that does not need an external diagnostic system.

A solution to the above problem is with the method according to Claim 1 created.

The method according to the invention works independently of one Diagnostic system self-sufficient and is triggered by at least one operating parameter of the vehicle, preferably a combination of operating parameters, one predetermined value or values.

The sub-claims 2 to 7 are advantageous embodiments of the directed method according to the invention.

The claim 8 gives the basic structure of a device for solving the Invention task.

The invention is described below with the aid of schematic drawings for example and explained in more detail.

It represent

Fig. 1 shows an example of a flow chart for performing the method according to the invention,

Fig. 2 is a schematic of an already known drive train of a vehicle with associated control device and

Fig. 3 is an already explained hydraulic actuation path in the transmission path from an actuator to the clutch.

The method according to the invention explained below can be carried out by corresponding configuration in the drive train already explained in FIGS. 2 and 3. It goes without saying that the drive train according to FIG. 2 can be modified in a wide variety of ways, in that it contains further sensors, a display is added, which is visible, for example, in the control panel, etc.

In the following of Figure 1, an example is at hand. For autonomous a routine according to the invention, that is, described by a diagnostic system free Tastpunkteinstellung at a startup of a vehicle at the end of a production facility.

The control unit 14 is programmed on the production side in such a way that a touch point actual value stored in the memory 29 is outside a tolerance range likewise stored in the memory. This is an advantageous necessary and at the same time sufficient prerequisite for a completely new touch point setting and not just an update. Furthermore, a sequence of three touch point setting request bytes is set in the control unit, one of which is reset from a request value after a touch value setting. Each byte can only consist of one bit.

On a roll at the end of the conveyor belt, you normally only drive and there the handbrake is not activated in any normal sequence. For this reason, the actuation of the hand brake, which is detected via the output signal of the sensor 30 b ( FIG. 2), can be used as a trigger signal for a touch point setting.

If it is determined in step 100 according to FIG. 1 that a predetermined operating state exists, which consists in the vehicle being stationary, the handbrake being applied, the engine idling and no gear being engaged, this becomes a request for a touch point setting understood by the control unit 14 .

If it is subsequently determined in step 102 that the touch point currently stored in the control device lies outside a tolerance band and that the touch value setting request byte has a request value that is, for example, non-zero, a sniffing process is first carried out in step 104 , within which, as explained above , The setting of the transmission path between the electric motor 43 and the release lever 54 is updated or set in a predetermined manner. Even if there is no hydraulic link, such an "adjustment" can be expedient, in which case there is no sniffing process, but a purely mechanical transmission link is adjusted to compensate for play.

After the sniffing process, the completion of which is shown in a display of the vehicle, for example, the clutch is fully opened and in step 106 it is checked whether the driver (or the system) has engaged a gear. If this is the case, a touch point setting takes place in step 108 , during which the clutch is slowly closed and the engine torque is recorded. The actuation of the clutch in the closing direction continues until the torque transmitted by the clutch assumes a predetermined value of, for example, around 3 Nm. The associated position of the electric motor 43 or of the position transmitter 32 is stored as the actual value touch point. The clutch is then fully opened again.

As determined in step 110 that the touch point actual value lies in the tolerance band, in step 112 the first touch value setting request byte TWEAB is deleted or set to zero. If it is determined in step 110 that the actual value touch point is still outside the tolerance band, the system returns to step 102 . An error is displayed at the latest when the cycle is run again unsuccessfully.

After the first sample setting request byte is cleared, the system returns to step 100 . If, for example, after the roller has been driven for a certain period of time, the operating state "handbrake applied, engine idling, zero gear engaged" is present again, the system proceeds to step 102 , which is however now modified so that no more it is checked whether the currently stored actual touch point value lies outside the tolerance band, but only consists in checking whether there is a further touch value setting request byte. If this is the case, steps 104 to 112 proceed as described above, step 110 being omitted or, if it is found that the actual actual touch point value is not within the tolerance band, an error is displayed immediately.

If the second sample value setting request byte is deleted in step 112 , the system proceeds to step 114 , in which it is checked whether a predetermined range of performance has been achieved on the roll, for example whether the speed of 100 km / h has been exceeded at least once. If this is the case, steps 100 , 102 , 104 , 106 , 108 , 110 and 112 are carried out again, the third sample value request byte being deleted in step 112 and the sample point setting at the end of the tape being ended in step 116 , since after driving through a high load point, the renewed touch point setting has led to a flawless and optimal touch point for vehicle operation. It goes without saying that step 102 following step 114 merely consists in checking whether a sample value setting request byte (the third) is still present, upon which a new sample point setting with previous sniffing is carried out.

The method according to the invention can be modified in many different ways. For example, the number of sample setting request bytes initially programmed, which determines the number of initial sample settings, may be different from three. The conditions under which a new sample value setting is carried out can be of various types. The driver can be guided visually and / or acoustically to perform certain actions, for example engaging a gear, removing the gear, actuating the handbrake, releasing the handbrake. In step 106 or in step 100, there may be an additional condition that the foot brake must also be actuated. The foot brake can be actuated by the system (control unit 34 ) or by the driver himself. Likewise, the system can engage or remove a drive if an automatically shifting transmission is provided.

The procedure described cannot only be used at the end of the line during commissioning a new vehicle can be used; it can also be used when after replacing components or major repairs the touch point completely must be reset in which the control unit with Request bytes are reprogrammed accordingly.

The claims filed with the application are Proposed wording without prejudice for obtaining further patent protection. The The applicant reserves the right to add more, so far only in the description and / or To claim drawings disclosed combination of features.

Relationships used in subclaims point to the others Training the subject of the main claim by the features of respective subclaim; they are not considered a waiver of achieving one independent, objective protection for the combinations of features of to understand related subclaims.

Since the subjects of the subclaims with regard to the prior art reserves the right to make its own and independent inventions on the priority day Applicant before becoming the subject of independent claims or To make divisional declarations. You can continue to work independently Inventions contain one of the objects of the previous Have independent claims independent design.

The exemplary embodiments are not intended to limit the invention understand. Rather, there are numerous within the scope of the present disclosure Changes and modifications possible, especially such variants, elements and combinations and / or materials, for example by combination or modification of individual in connection with that in general Description and embodiments as well as the claims described and in features or elements contained in the drawings or Process steps for the person skilled in the art with regard to solving the problem can be found and through combinable features to a new item or new ones Lead process steps or process step sequences, also insofar as they Test and work procedures concern.

Claims (8)

1. A method for autonomously setting the touch point of an automated clutch contained in a drive train of a vehicle when it is started up, comprising the following steps: a) setting the touch point value to a start value outside a tolerance range, b) setting a predetermined number of sample value setting request bytes to a request value, c) detecting at least one operating parameter of the vehicle, d) triggering a touch point setting in that the operating parameter has a predetermined value, e) adjusting the clutch to a first touch point setting, f) storing the determined actual touch point value, g) comparing the actual touch point value with the tolerance range, h) deleting the first sample value setting request byte if the actual sample point value lies within the tolerance range, and i) repeating steps c) to h) in accordance with the number of sample value setting requests set. 2. The method according to claim 1, wherein step g) after the deletion of the first sample value setting request bytes is omitted. 3. The method according to claim 1 or 2, wherein to trigger a Touch point setting a vehicle brake must be applied. 4. The method according to any one of claims 1 to 3, wherein for performing a Touch point setting a vehicle brake actuates the vehicle stand still, in a gearbox contained in the drive train one gear be inserted and a drive motor of the vehicle must be idling. 5. The method according to any one of claims 1 to 4, wherein a last Touch point adjustment only takes place after the drive train in a predetermined manner was charged. 6. The method according to any one of claims 1 to 5, wherein the number of initially set tactile point request bytes is three. 7. The method according to any one of claims 1 to 6, wherein before the first Touch point setting the setting of a transmission path between one Clutch actuator and the clutch is updated. 8. Device for autonomously setting the touch point of an automated clutch contained in a drive train of a vehicle when it is started up
a drive motor for the vehicle, which is connected to a transmission via a clutch actuated by an actuator,
a control device equipped with a microprocessor and associated storage devices, the inputs of which are connected to sensors for detecting at least operating parameters of the drive motor and the transmission, from which the torque transmitted by the clutch can be derived, a program being stored in the storage devices such that the Method according to one of claims 1 to 7 can be carried out.