ITMI20011822A1 - CLUTCH ADJUSTMENT COMMAND DEVICE - Google Patents

Description

DESCRIPTION

The invention relates to a method and a device for the actualization of a reference position, deposited in an electronic control device, of an adjustment member of a clutch adjustment device.

Automated clutches find more and more use not only thanks; to the increase in comfort obtained with them, but also thanks to possible savings in consumption in motor vehicles.

Figure 4 shows an exemplary block diagram of an actuation line of a motor vehicle equipped with an automated clutch. According to Figure 4, the drive line of a motor vehicle contains an internal combustion engine 2, a clutch 4 and a gearbox 6, from which a drive shaft 8 leads to drive wheels not shown.

The gearbox 6 is for example an automated manual gearbox or a stepped pulley winding gearbox with continuously variable transmission ratio. For the actuation or for the actuation of the gearbox 6, an adjustment device 9 is required, which can be controlled by a selection device 10 by means of a selection lever 12 via a control device 14. It is understood that the selection device it can also be executed differently, for example as a classic gear lever (H-glyph) or as a lever with touch positions (+, -) for upward and downward shifting.

The clutch 4 is, for example, a friction disc clutch with an actuation device 16, which is performed hydraulically, electrically (by electric motor), electro-hydraulically or otherwise.

Sensors contained in the drive chain, such as a pressure sensor 18 for detecting the intake pressure of the engine 2, a speed sensor 20 for detecting the number of revolutions nM of the crankshaft of the engine, a sensor 22 for detecting the position α of an accelerator pedal 24, a sensor 26 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 unit 14.

In the control apparatus 14, which contains a microprocessor with associated memories 29, characteristic fields or programs are deposited, with which actuators are controlled, such as a load regulating member 30 for regulating the load of the motor 2, the actuation 16 of the clutch 4 as well as the adjustment device 9 of the gearbox 6. The individual actuators can be designed in such a way that their position is known directly in the control device 14, for example as stepper motors, or they can be provided additional position transducers.

Structure and function of the described device are per se known and therefore are not illustrated in detail. Depending on the desire of the driver communicated via the accelerator pedal 24 and the desire communicated via the selector lever 12, according to a travel program or a direction of travel, the load regulator 30, the actuating device 16 and the adjustment device 9 are operated in a mutually adapted manner according to the signals supplied by the sensors, so that a comfortable ride is obtained.

For the actuation of the clutch 4, for example, a characteristic curve is stored in a memory of the control unit 14, which establishes a nominal position, regulated by the actuation device 16, of the clutch 4, respectively of a clutch adjustment member 4 depending on a moment to be transmitted from time to time by the clutch 4. For reasons of adjustment quality, wear of the clutch and energy consumption of the drive device, the moment of the clutch which can be transmitted in each case must only be large what is strictly necessary. The moment to be transmitted required results from the driver's desire respectively from the position of the accelerator pedal 24 and for example from the load of the internal combustion engine 2, detected by the sensor 18, as well as possibly from further operating parameters, such as the number of revolutions of the motor 2 and so on.

The characteristic curve stored in the control device 14, which indicates the nominal distance of an actuating element, moved by the actuating device 16, as a function of the torque to be transmitted, calculated, has a decisive influence on a comfortable starting and a comfortable running of exchange processes. The characteristic curve varies over the life of the clutch and is updated respectively recorded, for example, depending on wear in the presence of predetermined operating conditions, for example a slip in the presence of a predetermined engine moment, complete closing or opening of the clutch and etc.

Figure 5 shows in detail an example of the actuation device 16.

A piston 38 works in a cylinder 36 filled with hydraulic fluid, the stem 40 of which has an external toothing, which meshes with an internal toothing of a gear 41, which meshes again with the external toothing of a pinion of an electric motor 42, the which is controlled by the control device 14 (Figure 4). The electric motor can be a conventional commutation motor, which is driven for example by means of a PWM signal. The cylinder 36 has a compensation hole 44, which is connected via a conduit 45 to a compensation vessel (not shown). A line 48 leads from the pressurized cavity 46 of the cylinder to a clutch actuation cylinder 50, in which operates an actuation piston 52, which is connected via its piston rod, for example, to the release lever. 54 of the clutch, forming an adjustment member. The position A, which is generally indicated as the zero position of the aeration clutch, is the position, at which the piston 38 according to Figure 4 passes to the right, in the pressure cavity 46 a pressure <1> is generated for the clutch operation.

For the determination of the position, for example on the gear 41 there is provided an incremental position transducer 52, known in its structure, which counts the teeth of the gear 41, which pass in front of it, and passes corresponding impulses to the control device 14. The number of these pulses is a direct measure of the movement of the release lever 54, at least as long as the plunger 38 is to the right of the compensation hole 44.

A problem, which arises in particular when using incremental position transducers or path sensors, is that the momentary position of the component whose position is to be detected is lost. This momentary position is present only when the counting state of the position transducer, corresponding to a reference position, is stored in the memory 29 of the control unit 14, and the number of increments respectively of the pulses, of which the momentary position differs differs from the reference position, it is known. Both the reference position and the counting state, whose momentary position differs from the reference position, can be lost due to the most disparate influences. The loss of the momentary position then no longer known can cause the drive device with full power supply to move a drive component against a standstill, which can lead directly to system failure, reduced service life or other incorrect functions. .

The invention is based on the task of realizing a method or a system of the type described at the beginning, with which in a simple and safe way it is possible to update a reference position, so that the position of the regulating member, which is important with reference actuation of the clutch, is known as safely as possible.

The process-related part of the aim of the invention is solved with the features of claim 1. With this process, a high degree of flexibility in updating is achieved, so that after a loss of the position information, the position can be detected again quickly and accurately.

At the basis of the method according to the invention there is in particular the idea that, in situations, in which the possible direction of the actuation of the regulating member for actuation or compensation of a reference position is not unambiguous, for for example, in the case of a slipping clutch, the compensation direction or the actualization direction is established by means of further signals, which are activated by the driver, or, if this is not possible, the instantaneous position is maintained.

Sub-claims 2 to 5 relate to advantageous embodiments of the method according to the invention.

Claim 6 characterizes the basic structure of a system for solving the related part of the aim of the invention.

The invention can be used for almost all types of automated clutch actuation, in which the position of an adjusting member must be known. Particularly advantageously, the invention can be used for those clutch actuations in which an incremental distance sensor is present.

The invention is illustrated below on the basis of schematic drawings by way of example and with further details

Figures 1 to 3 represent flowcharts to illustrate the invention,

Figure 4 shows the block diagram already illustrated of an actuation line of a vehicle with an automated clutch e

Figure 5 represents an already illustrated example of a confirmation device.

In a clutch there are normally two reference positions of an actuation member, that is, a first reference position, in which the clutch is completely closed, and a second reference position, in which the clutch is completely open. These positions are defined for example by means of stops or by the fact that the actuation force for the displacement of the adjusting member, in the example of the release lever 54, changes suddenly. Information on the position referred to a reference position, respectively on the absolute position of an adjustment element, can be "lost" when the position Xn-1, prior to the count of an increment Δ χ, is no longer correct, since the position Xn momentary is determined from time to time by the last position and by the displacement of an increment.

Such a data loss or such an error typically occurs

- in the case of a reset, where the system can be in any state, for example as a result of undervoltages (due to program travel time errors, resets cannot generally be caused),

- due to a conversion or a change in mechanical conditions or

- due to electromagnetic compatibility (EMV) problems.

Since a loss of the last position of the actuating element cannot be excluded, the system must be able to update or compensate for the position information, as a reference position is approached, it is compared with the stored values and the values if stored, they are corrected. This must be possible in an inconspicuous way, without loss of comfort for the passengers of the vehicle and as much as possible in every driving situation.

A discounting or a compensation must take place on a regular basis

- in the case of a system startup,

- in the case of a reset,

- in case of implausible values, for example when a clutch slip is determined, even if the moment characteristic curve stored at the operating point does not allow any slip or another unexpected operating point of the clutch is recognized,

- in the case of unexpected mechanical resistance or

- for regular checking of stored values.

An update of the route information takes place, for example, as follows:

as soon as the request for an update occurs, the drive unit, an electric motor in the example of Figure 5, is controlled by the control device 14 in a way that is no longer position-controlled, but voltage-controlled. The recognition of a reference position (fully closed or fully open clutch) takes place for example by a sudden increase in current as a result of a sudden increase in force or as a result of a sudden decrease in current as a result of a sudden decrease in force.

The following table shows typical driving situations, which are each connected with determined status parameters of the drive line, which are detected by the sensors represented in figure 4. The driving situation is determined independently of the clutch actuation position or the driving position. clutch displacement, where it is important to know the gear engaged in each case corresponding to the indicated driving situation.

In the table, the running status means a respective "software mode" of the clutch, ie a program, corresponding to which the clutch is controlled in each case. It is understood that different driving situations can arise within one mode, resulting in the multiple mentions in line 2.

With the individual running states this means:

8: normal gear

7: slow forward (starting)

6: dragging

5: disengagement for gear change

4: neutral gear

3: neutral ventilation

2: ignition "off" and shutdown

"+" in columns 3 and 4 means from time to time that an actualization is possible immediately, "0" means that an update is possible to a limited extent, and "-" means that an update is impossible.

As can be seen from the table, states 3 to 6 allow instantaneous actualization or instant compensation so that the clutch is opened and in this case the fully open reference position is updated. The states 2, 3 and 4 as well as 8 allow instant updating in the closing direction of the clutch.

By compensation process is meant a process in which the plunger 38 according to FIG. 5 is moved to the left beyond the compensation hole 44, and is then moved back to the right, until it passes the compensation hole. Thanks to the compensation it is possible to compensate the volume of the hydraulic system. Usually the clutch in this case is completely closed, since a force can be applied to the release lever 54 (Figure 5) from the piston 38 only when the piston 38 passes the compensation hole 44 from the left.

As can be seen from the table, in most driving situations an actuation can be carried out immediately by approaching one of the two reference positions.

Examples of implementation strategies are shown below: 1. Behavior in the event of requested discounting and skidding When driving slowly and starting, the driver's wishes must be taken into account for safety reasons. Examples of safety critical situations are:

- when starting, the driver brakes, as there are children on the road, but the clutch is closed and the vehicle "leaps" forward.

- When starting uphill, the driver gives the throttle, but the clutch opens and the vehicle rolls backwards.

In order to avoid these critical situations, in the event of a slipping clutch there is no actualization or no compensation until a desire from the driver is recognizable, indicating the direction of compensation. The driver's desire can be indicated by actuating the brake pedal (open the clutch) or the gas pedal (close the clutch).

Figure 1 shows a flow chart:

when in step 60 an update or compensation is requested, in step 62 first of all it is checked whether the clutch slips. If so, in step 64 it is checked whether the brake is applied. If so, then the system decides that the clutch in step 66 is opened, after which a position compensation occurs in step 72, as the reference position is approached completely open. If in step 62 it is determined that no slippage is present, then, when one of the affected situations of the aforementioned table is present, in step 66 the clutch is opened and in step 72 the position compensation takes place. If in step 64 it is determined that the brake is not actuated, then in step 68 it is checked how hard the gas pedal is actuated. If this is operated sufficiently, then in step 70 the clutch is closed, after which in step 72 the closed reference position is approached. If in step 68 it is determined that the pedal value is insufficient, the system will go back to step 72. '

It is understood that when the clutch is closed by means of a pure voltage control of the engine 42, the gradient of the number of revolutions of the engine 2 of the vehicle must be taken into account, in order to avoid throttling of the engine.

2. Coarse reference of the position

During the slipping phase for the MKupp clutch moment the following applies:

where MMot is the motor moment detectable through the sensors, J is the moment of inertia of the motor and dω / dt is the temporal variation of its angular speed.

In the control device 14, the nominal position of the actuating member or the nominal path of the clutch is usually calculated from the nominal clutch torque. In this case, the moment characteristic curve is adapted with adaptation parameters (coefficient of friction, gripping point) over the service life. If these parameters are known, the momentary position can be calculated from the moment of the momentary clutch. This position can be used as an initialization value, on the basis of which the clutch is closed with the normal control strategy.

The conditions are represented in figure 2:

in step 80 the request is made for an actualization respectively of a compensation. If the clutch in the meantime is in the slipping state, in step 82, as previously illustrated, the clutch moment is determined and from this, on the basis of the moment characteristic curve, the position of the clutch is determined. This clutch position can be used as a rough reference value for further control of the clutch actuation. For example, in step 84 it can be determined whether the slip has been disposed of. If this is the case, then in step 86 an update takes place with, for example, voltage control of the electric motor 42. If this is not the case, then the clutch can be further actuated (step 88) while maintaining the normal control strategy. If in step 80 it is determined that there is no slip, the system goes directly to step 86. At the end of step 88 the system jumps to step 84.

3. Regular updating in neutral

For the highest possible certainty of the knowledge of the position it is necessary to check it regularly. Therefore, in situations determined according to routine, an update can be activated, where this update must take place in such a way that the driver does not perceive it. A particularly well suited situation is present in the quiet state of the vehicle with the engine running and neutral gear engaged. In this state, the clutch can be closed or even opened completely, so that its entire effective range can be traversed and both reference positions can be updated. After an update, the gripping point may need to be moved together. Adaptations must be moved or adapted accordingly.

4. Regular updating while driving

An additional updating option exists in status 8 (see table). Normally the clutch is not completely closed, but only in such a way that the transmissible clutch momentum is slightly above the engine moment (moment tracking). This has the advantage that less time is required for the clutch to open. For updating, the clutch is operated in the closing direction. For volume compensation according to routine in the hydraulic drive (compensation), the clutch is also completely closed, so that the updating of the closed position can take place simultaneously with a compensation process.

A strategy is also conceivable, in which in the case of a certain certainty of position knowledge, the clutch is brought as quickly as possible to the vicinity of its closed position, and therefore with tension adjustment the closed position is updated. When the clutch is closed completely, both discounting and volume compensation (compensation) can take place each time.

5. Coarse discounting for a pressed clutch

In the case of a system, the stoppage of which cannot be recognized exactly reproducibly (for example in the case of a depressed clutch), a coarse update may take place in this direction. When a stop in this direction is within the known imprecision, it is assumed that the momentary position is known with some certainty and the old position continues to be considered valid. For safety, the power supply to the motor can be limited in the vicinity of the end positions, until a precise compensation or a precise update can be carried out. If no update has yet been carried out or the stop is outside the valid inaccuracies, the position indicated by the incremental displacement encoder is permanently described as the momentary position. The updating takes place as soon as the possibilities exist for this purpose.

The flow chart according to Figure 4 illustrates the conditions: in step 90 an update in the closing direction of the clutch is requested. In step 92 a closing commanded in voltage occurs. In step 94 the reaching of a stop is recognized. In step 96 it is checked whether the position of the recognized stop differs from the stored reference position by more than one threshold value. If this is the case, then in step 98 the position recognized in step 94 is stored as the new reference position. In step 100 the coarse compensation is concluded, but precise compensation is requested as quickly as possible. If the difference in step 96 is below the threshold value, then in step 102 the position is not updated, but in step 101 a precise compensation is requested as quickly as possible.

6. Discount according to trust

If the position knowledge is not sure, then in the next possible situation, for example during normal travel in the closing direction of the clutch or in the neutral gear position in the opening direction of the clutch, an update takes place. In the absence of safety, the power with which the electric motor is controlled can be limited.

The patent claims filed with the application are proposed for formulation without prejudice to obtain further patent production. The Applicant reserves the right to claim still further combinations of characteristics disclosed so far only in the description and / or in the drawings.

References used in sub-claims refer to the further embodiment of the subject matter of the main claims by means of the characteristics of the respective sub-claim; they are not to be understood as a waiver of obtaining autonomous objective protection for the combinations of characteristics of the sub-claims containing the references.

Since the objects of the sub-claims as regards the state of the art on the priority day can form their own and autonomous inventions, the applicant reserves the right to make them the subject of independent claims or divisional applications. They may also contain autonomous inventions, which have a configuration independent of the objects of the preceding sub-claims.

The embodiments are not to be understood as a limitation of the invention. On the other hand, numerous variations and modifications are possible within the present description, in particular such variations, elements and combinations and / or materials, which for example by combining or modifying individual characteristics or elements or process steps described in connection with the general description and the embodiments as well as the claims, and contained in the drawings, are detectable by the skilled person as regards the solution of the task, and by means of combinable characteristics they lead to a new object or to new process steps or sequences of process steps, also for with regard to manufacturing, testing and working procedures.

Claims (7)

CLAIMS 1. Method for the actualization of a reference position, deposited in an electronic control device, of an adjusting member of a clutch adjusting device of a clutch contained in the drive line of a vehicle, with an actuation unit , controlled by the control device, for the actuation of the regulating organ, at whose displacement the regulating organ is actuated for the updating of the reference position, the reaching of the reference position is recognized due to the fact that a parameter varies in a predetermined way, and a value corresponding to the momentary reference position reached is stored as an updated reference position, where on an authorization request the status parameters of the drive line, in which the clutch is located, and the updating takes place independently of the status parameters. Method according to claim 1, wherein a distance measurement of the actuating element of the actuator is performed incrementally. Method according to claim 1 or 2, where a first reference position corresponds to the closed clutch and a second reference position to the open clutch, and in the case of a slipping clutch a reference position is approached only depending on the presence of parameters predetermined situations, corresponding to the defined intentions of an operator. Method according to one of claims 1 to 3, wherein a programmed position of the regulating member is determined by the torque moment transmitted by the clutch, and by a moment characteristic curve stored in the control device, and is placed at the base as instant actual position for further clutch operation. Method according to one of claims 1 to 4, wherein the vehicle is stationary, the gearbox is in neutral and the engine is running. Method according to one of claims 1 to 5, where in the event of inaccurate recognition of a reference position, this reference position is approached and an implementation takes place only when the recognized reference position differs from the previously stored one by more than one predetermined threshold value. 7. Device for the actualization of a reference position, deposited in an electronic control device, of an adjustment member of a clutch adjustment device of a clutch contained in the drive line of a vehicle, containing a drive unit actuation, controlled by the control device, for the actuation of the regulating member, a distance measuring device operating incrementally for detecting the distance traveled by the regulating member, a device for detecting the reaching of a position of the control unit and for storing the relative output signal of the incremental distance measuring device as a reference position and sensors for detecting the status parameters of the drive line, where the control device, on a request discounting for a reference position, commands a dependent discounting from the drive line status parameters.