DE102015204270A1 - Method and device for the method for determining a shift request of a driver of a motor vehicle - Google Patents

Abstract

A method of driving an actuator (40) of an actuatable clutch (20) of a motor vehicle to which a torque generated by a motor (10) is transmitted through a clutch input side shaft (21), wherein if there is a shift request of a driver of the motor vehicle, the Actuator (40) is driven so that a maximum of the clutch (20) transmittable torque is changed depending on a voltage applied to the coupling input side shaft (21) input torque.

Description

State of the art

The invention relates to a method for driving an actuator of an actuatable clutch of a motor vehicle. The invention further relates to a device, in particular a control device, which is set up to carry out this method.

From the not pre-published DE 10 2014 203 958 a method for determining a beginning of a measurable torque transmission of an automated clutch of a motor vehicle is known in which the automated clutch is initially opened during a switching operation only up to a predetermined threshold, which corresponds to an expected position of the automated clutch at the beginning of the measurable torque transmission.

Disclosure of the invention

The method having the features of independent claim 1 has the advantage that the load of the actuator can be reduced and thus can be designed for fewer operating hours. As a result, a cost and / or weight reduction or gain in dynamics of the actuator can be achieved.

In a first aspect, a method for driving an actuator of an actuatable clutch of a motor vehicle may be provided. On the clutch, a torque generated by an engine is transmitted through a clutch input side shaft, for example, a crankshaft. When a shift request of a driver of the motor vehicle is present, the actuator is driven so that a torque which can be transmitted to the maximum of the clutch is changed depending on an input torque applied to the clutch input side shaft. This change of the maximum transmittable torque is referred to below as torque tracking or simply tracking. Under a shift request here the intention to change a gear is understood a gearbox, d. H. that the change of gear is imminent.

The torque control reduces the opening time of the clutch and the shift request can be quickly implemented. However, the actuator changes its position in this tracking of the maximum transmittable torque. Characterized in that the tracking is performed depending on whether there is an intention to change gear, resulting in the described reduced load on the actuator. In particular, it can be provided that when it is detected that no switching request is present or that when no switching request is detected, the tracking is not performed.

When tracking can be provided in particular that the maximum transmittable torque exceeds the input torque by not more than a predetermined maximum difference, but in particular does not fall below.

It can be provided in a further aspect that is detected depending on a degree of actuation of an accelerator pedal, if the shift request is present.

In particular, it can then be recognized that the shift request is present when a change over time of the degree of actuation of the accelerator pedal is greater than a relief threshold value. This can be provided in particular in the case of negative changes, that is to say in the event of relief of the accelerator pedal. It can then be recognized particularly easily for a present switching request if this relief takes place quickly, ie if the absolute value of the (negative) temporal change is greater than the relief threshold value.

In a further aspect, it can be provided that it is detected as a function of a rotational speed of the engine whether the shift request is present. This is also a particularly simple method for detecting the shift request. In particular, it can be provided that it is then detected on the shift request when the speed is lower than a lower speed threshold. In this case, shifting to a lower gear is likely. It can also be provided that is then detected on the shift request, if the speed is greater than an upper speed threshold. In this case, shifting to a higher gear is likely.

In a further aspect, the determination of the shift request can be made depending on a degree of actuation of a shift lever. The shift request can then be dependent on a first signal which characterizes the degree of actuation of a shift lever of the motor vehicle and is dependent on a second signal, which is determined by filtering the first signal, take place. The shift lever may be mounted on a shaft to be engaged when switching a shift gate. The shaft then rotates when engaging a gear. In this case, the degree of actuation corresponds, for example, to a rotation angle of the shaft.

This has the advantage that the determination of the desired shift is done adaptively. If the determination of the degree of actuation is carried out with the aid of a sensor, Thus, with this method, a drift of the sensor signal due to variable length expansions of components (eg, under temperature influences) can be compensated. Other environmental influences can also be compensated. The determination of the shift request is thus particularly robust. The process is also very easy to implement.

In this case, it can be provided in a particularly simple embodiment that the switching request is determined as a function of a comparison of the first signal with a variable threshold value, this variable threshold value being dependent on the second signal. It can be provided that it is then detected on a switching request, if the comparison shows that the first signal has cut the variable threshold, so that the difference between the first signal and the variable threshold changes its sign.

In a further particularly simple further development, it can be provided that the variable threshold value is determined by applying a (for example multiplicative or additive) offset to the second signal. Ie. the variable threshold value can be determined as the product or as the sum of the second signal with the offset.

If the offset selected depending on a currently engaged gear of a gearbox of the motor vehicle, the method can be particularly easy to use when the shift gates are arranged in an H-shape.

In particular, it may be provided in one embodiment of this aspect that the offset is positive when the shift lever for laying the currently engaged gear in the direction of a larger Aktuierungsgrads must be moved, and wherein the offset is negative when the lever for laying out the currently engaged gear must be moved in the direction of a lower Aktuierungsgrads.

In a further aspect, it can be provided that the filtering of the first signal is performed by means of a filter having an output signal and an input signal, wherein the output signal is determined by delaying and / or storing the input signal. With such a filter, a robust method of the type described above can be implemented in a particularly simple manner. For example, in a particularly simple embodiment, the filter may be a PT1 filter.

In other aspects, the invention relates to a computer program configured to perform all the steps of one of the methods of any of the foregoing aspects, an electronic storage medium storing the computer program, and a controller configured to perform all the steps of one of the methods of one to carry out the aforementioned aspects.

The figures show examples of particularly advantageous embodiments of the invention. Show it:

1 a topology of a powertrain;

2 a flowchart of a first possible method for switching desire recognition;

3 a flowchart for a second possible method for Schaltwunscherkennung;

4 a structural diagram of a third possible method for Schaltwunscherkennung;

5 Signal curves in the switching request recognition according to 4 ;

6 a flowchart for the operation of a method for opening a semi-automatic clutch.

Description of the embodiments

1 shows a topology of a powertrain of a motor vehicle 1 in which the method according to the invention can proceed. The car 1 has an internal combustion engine 10 up, over a clutch 20 separable with a manual transmission 30 connected is. A crankshaft 21 transfers from the combustion engine 10 generated torque on the clutch 10 , A clutch output side shaft 22 transfers from the clutch 10 transmitted torque to the manual transmission 30 , Shown here is a semi-automatic transmission. The coupling 20 is from a clutch actuator 40 aktuierbar. The manual transmission 30 is a manual transmission. The gear selection is via a lever 50 who is in a switching tree 51 in shift gates gR, g1, g2, g3, g4, g5, g6 can be moved, which in each case the selection of a gear of the gearbox 30 correspond. Shift gate gR corresponds to reverse gear, shift gate g1 to first gear, shift gate g2 to second gear, shift gate g3 to third gear, shift gate g4 to fourth gear, shift gate g5 to fifth gear and shift gate g6 to sixth gear. The shifter 50 is to implement the Schaltwunsches via a mechanical connection 60 with the gearbox 30 coupled.

The shifter 50 is stored in this example on a (not shown) shaft. When the shift lever 50 in one of the upper shift gates gR, g1, g3, g5 is introduced, the shaft rotates forward. When the shift lever 50 is inserted into one of the lower shift gates g2, g4, g6, the shaft rotates backwards. A rotation angle sensor 80 is mounted on this shaft to determine the rotation angle of the shaft.

An absolute gear sensor 70 can be in operative connection with the mechanical connection 70 be provided to the in the manual transmission 30 determine the gear engaged. This determined gear is then sent to a control unit 15 transmitted. The control unit 15 is for example the engine control unit.

Likewise, the rotation angle sensor transmits 80 a signal that characterizes the angle of rotation of the shaft, to the controller 80 , On the control unit 80 the process according to the invention can proceed. This can be done in the control unit 80 an electronic storage medium 16 be provided on which a computer program is stored, and which is programmed so that it performs the inventive method when it is on the control unit 80 expires.

Furthermore, the motor vehicle 1 a clutch pedal (not shown), whose degree of actuation of a clutch sensor 90 determined and to the control unit 15 can be transmitted. In such a case, on the one hand, the driver of the motor vehicle 1 by pressing the clutch pedal the clutch 20 to open. On the other hand, there is also an automatic opening of the clutch 20 possible.

Furthermore, the motor vehicle 1 an accelerator pedal 94 whose degree of actuation of an accelerator pedal sensor 95 determined and to the control unit 15 can be transmitted.

2 shows by way of example how a first aspect of the shift request recognition can proceed. In step 400 starts the procedure. The degree of actuation of the accelerator pedal 94 is recorded. The absolute value of the temporal rate of change of the degree of actuation is determined. It follows step 410 in which it is compared whether the absolute value of the time rate of change is greater than a predefinable discharge threshold value. If this is the case, follow step 420 in which it is decided that the shift request is present. Otherwise, follow step 430 in which it is decided that with this method was not recognized that the shift request is present.

3 shows by way of example how a second aspect of the shift request recognition can proceed. In step 500 starts the procedure. A speed of the crankshaft 21 , the speed of the internal combustion engine 10 is determined, is determined, for example via a speed sensor. It follows step 510 in which it is determined whether the speed is less than a lower speed threshold. If this is the case, follow step 520 in which it is decided that the shift request is present. Otherwise, follow step 530 , In step 530 it is determined whether the speed is greater than an upper speed threshold. If this is the case, step follows as well 520 , Otherwise, follow step 540 , in which it is decided that it was not recognized that this method was not recognized that the switching request exists. Of course it is also possible that by step 500 not to step 510 but immediately to step 530 is branched. Alternatively, it is possible that of step 510 not to step 530 but immediately to step 540 is branched.

4 shows by way of example how a third aspect of the shift request recognition can proceed. The rotation angle sensor 80 transmits the rotation angle of the shaft a filter 100 and also to a shift request detection unit 150 , The detected rotation angle of the shaft is referred to in this application as the first signal.

One unity 110 is set up to recognize that the shift request of the driver is completed. The unit 110 transmits a signal to a timer 120 when she recognizes that the driver's shift request has ended. For example, a termination of the shift request can be detected if it was detected that the gear has been engaged.

The filter 100 gives a second signal to an offset generation unit 140 out. The filter 100 may be a PT1 filter which receives the second signal as an input and outputs a correspondingly filtered signal with the second variable as the output variable. It is not critical that the filter 100 is a PT1 filter. However, the PT1 filter is particularly easy to implement. However, other filters may be used as long as these filters cause the output signal to be obtained substantially by delaying the input signal. The filter 100 may for example also be a storing element that writes the values of the input quantity as time series into a FIFO buffer and outputs this time series with a time offset as the output variable.

However, it may be provided that the filter 100 only the function described has, if it from the timer 120 has received a corresponding signal. In the embodiment, it is provided that the timer 120 after the completion of the switching request a predetermined time period waits, and after this period a signal to the filter 100 transmitted. Before receiving this signal, the filter outputs 100 a predefinable but fixed value. Upon receipt of this signal, the filter returns 100 the filtered one first signal off. This filtered first signal is referred to as a second signal in the context of this patent application.

The gear sensor 70 transmits a signal characterizing the currently engaged gear to the gear recognition unit 130 , The gear recognition unit 130 determines from the current characterizing signal characterizing the currently engaged gear and transmits it to the offset generation unit 140 and the shift request detection unit 150 ,

The offset generation unit 140 Checks whether the pre-detection has already recognized that a switching operation should be performed. In this case, it is decided that the second phase of the shift detection method is performed, otherwise the first phase of the procedure is performed.

Depending on the transmitted gear, the sign of the offset is selected. For gears where the position of the lever 50 corresponds to a positive direction of rotation of the shaft, the sign of the offset is negatively selected, for gears in which the position of the lever 50 corresponds to a negative direction of rotation, the sign of the offset is selected positive. In the example in which a positive direction of rotation of the shaft corresponds to the first, third and fifth gear, while a negative direction of rotation of the shaft corresponds to the second, fourth, sixth gear, the sign is negatively selected when detected first, third, fifth gear, while at recognized second, fourth, sixth gear the sign is chosen positive.

This offset is from the offset generation unit 140 on the filter 100 For example, in order to obtain the variable threshold value, this variable threshold value is added to the shift request recognition unit 150 transmitted.

The switch request generation unit 150 compares the variable threshold with the first signal. Represents the button generation unit 150 If it is determined that the first signal intersects the variable threshold value, then it is detected that the switching request is present.

5 illustrates this switching desire recognition according to 4 For example, in a shift in which first is switched to the fourth gear and then the hand is placed on the shift lever. On the abscissa the time t is plotted, on the ordinate the degree of actuation A of the shift lever 50 , Shown is the time profile of the first signal s and a first variable threshold schw1, which corresponds to a positive offset described above. This is the variable threshold, which in the example of 2 to the shift request detection unit 150 is transmitted.

Also shown for clarity is a second variable threshold schw2, which is determined as well as the first variable threshold schw1, only with a negative offset. In a first period T1, the gear is engaged. The degree of actuation drops only rapidly, passes through a short minimum to finally assume an approximately constant value in a second time period T2. Due to the smoothing behavior of the filter 100 For example, the first variable threshold value schw1 and the second variable threshold value T2 do not show this overshoot behavior.

The absolute value of the offset is initially chosen to be large. With the beginning of the second period T2, the above-described first phase of the shift request recognition begins. The absolute value of the offset is set to a low value z. B. lowered with a ramp function. The band spanned by the first variable threshold schw1 and the second variable threshold schw2 is now very narrow. Because the shift lever 50 is in its rest position, the value of the first signal s remains in this band.

In a subsequent to the second period T2 period T3 is now illustrated what happens when the driver of the motor vehicle 1 his hand on the gear lever 50 hangs up. The shifter 50 thereby changes its degree of actuation A and the value of the first signal s increases, for example. At a first time t1, the profile of the first signal s crosses the course of the first variable threshold value schw1, ie, since the beginning of the first phase, the value of the first signal s is for the first time greater than the value of the first variable threshold value schw1.

The shift request detection unit 150 recognizes here that the switching request is detected.

6 shows by way of example the sequence of a method for opening the clutch 20 , In step 1010 the method according to 2 executed. It gets to step 1040 whether it has been detected with this method that the switching request is present.

Parallel will be in step 1020 the method according to 3 executed. It gets to step 1040 whether it has been detected with this method that the switching request is present.

Parallel will be in step 1030 the method according to 4 executed. It gets to step 1040 whether it has been detected with this method that the switching request is present.

Of course, it is possible that only two of these three methods or only one of these three methods are executed in parallel.

In step 1040 these three results are logically ORed and the result is sent to step 1050 transmitted. Ie. If at least one of the parallel methods has determined that the shift request is present, it is sent to step 1050 notified that the shift request is present, otherwise it will be sent to step 1050 transmitted that the shift request is not present.

In step 1050 a check is made as to whether the shift request is present and to step 1060 branches if the shade is not present and to step 1070 Branched when the shift request is present. In step 1060 the procedure ends.

In step 1070 Torque tracking is activated. That on the crankshaft 21 applied torque is determined. This is done for example from a map that in the electronic storage medium 16 is deposited. This map addresses that of the combustion engine 10 generated torque via operating parameters of the internal combustion engine 10 , The predefinable maximum difference is added to the value of the torque thus determined, which results in a desired clutch torque. The desired clutch maximum torque is the torque that is the clutch 20 should be able to transmit maximum. For example, via a map from the determined torque and the desired clutch maximum torque is a suitable control for the clutch actuator 40 determined, which is such that of the clutch 20 maximum transmittable torque is greater than the determined torque and not greater than the desired clutch maximum torque. The clutch actuator 40 is then controlled with this appropriate control. The process steps of this process for torque tracking are repeated continuously, so that of the clutch 20 maximum transferable torque from the internal combustion engine 10 generated torque follows.

It follows step 1080 in which it is determined whether a circuit is actually performed, for example via an analysis of the rotation angle sensor 80 transmitted signal. If this is not the case within a predefinable time interval after the switching request has been detected, then step follows 1100 , Torque tracking is disabled and the process ends.

If this is the case, step follows 1090 , In step 1090 the clutch is opened and torque tracking also ends. In the further course can be checked whether a new gear was engaged and the clutch then closed again. This ends the procedure.

It will be understood by those skilled in the art that the method described may be implemented in software, or in hardware, or in a hybrid of hardware and software.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102014203958 [0002]

Claims (13)

Method for actuating an actuator ( 40 ) an actuatable coupling ( 20 ) of a motor vehicle ( 1 ) on the one of a motor ( 10 ) torque generated by a coupling input side shaft ( 21 ), wherein when a shift request of a driver of the motor vehicle ( 1 ), the actuator ( 40 ) is driven so that a maximum of the clutch ( 20 ) transmissible torque depending on a on the clutch input side shaft ( 21 ) applied input torque is changed. The method of claim 1, wherein the maximum transmittable torque exceeds the input torque by no more than a predetermined maximum difference. Method according to claim 1 or 2, wherein, depending on an actuation degree of an accelerator pedal ( 94 ) is detected, whether the switching request is present. A method according to claim 3, wherein it is then recognized that the switching request is present when a temporal change of the degree of actuation of the accelerator pedal ( 94 ) is greater than a relief threshold. Method according to one of the preceding claims, wherein depending on a rotational speed of the engine ( 10 ) is detected, whether the switching request is present. Method according to one of the preceding claims, wherein the presence of the shift request depending on a first signal (s), which a degree of actuation of a shift lever ( 50 ) of the motor vehicle is detected, and is detected as a function of a second signal, which was determined by filtering the first signal (s). Method according to Claim 6, wherein the switching request is determined as a function of a comparison of the first signal (s) with a variable threshold value (schw1, schw2, schw3), this variable threshold value (schw1, schw2, schw3) being dependent on the second signal. The method of claim 7, wherein the variable threshold (schw1, schw2, schw3) is determined by applying an offset to the second signal. The method of claim 8, wherein the offset depending on a currently engaged gear of a manual transmission ( 30 ) of the motor vehicle ( 1 ) is selected. Method according to one of claims 6 to 9, wherein the filtering by means of a filter ( 100 ), wherein an output signal of the filter ( 100 ) by delaying and / or storing an input signal of the filter ( 100 ) is determined. Computer program adapted to carry out all the steps of one of the methods according to one of Claims 1 to 10. Electronic storage medium ( 16 ) on which the computer program according to claim 10 is stored. Control unit ( 15 ) arranged to carry out all the steps of one of the methods according to one of claims 1 to 10.

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