DE102013021373A1 - Switching method for automatic transmission of motor vehicle, involves storing target state during sequence of time period, and converting target state into actual state of automatic transmission after sequence of time period - Google Patents

Abstract

The method involves specifying a target state (15) by deflections (10, 14) of a selector lever of an automatic transmission of a motor vehicle from a middle position (12). A time period, which relates to a specification (13) of the target state, is determined based on an operating parameter e.g. rotational speed gradient, of the motor vehicle. The lever is automatically reset into the middle position. The target state is stored during a sequence of the time period. The target state is converted into an actual state of the automatic transmission after the sequence of the time period.

Description

The invention relates to a shift method for an automatic transmission of a motor vehicle, in which the automatic transmission comprises a selector lever, which is used to specify different target states to the automatic transmission by deflection of the selector lever from a central position. In this case, a specification of one of the desired states by deflection of the selector lever from its center position. Furthermore, the invention relates to an automatic transmission of a motor vehicle according to the preamble of patent claim 5.

Such an automatic transmission is for example the DE 20 2004 019 677 U1 to be known as known. The local automatic transmission of a motor vehicle comprises an actuating device with a selector lever and a control device which is in signal connection with the selector lever. The actuating device further comprises at least one controllable by the control device actuator, wherein different driving ranges (R, N, D) are selectable by the actuator. By deflecting the selector lever along a shift gate in at least two deflection directions certain driving levels (R, N, D) of the automatic transmission can be selected. The selector lever has a centered center position, in which it automatically resets itself from both deflection directions and in a deflection direction of the selector lever two different driving levels (R, N, D) are selectable by the selector lever for selecting one of the first driving levels (R, N, D) is deflected to a first stop and is deflected to select a second drive stage (R, N, D) after overriding the first stop in the same direction of deflection to a second stop. The actuator is arranged outside a housing of the automatic transmission.

If the vehicle driver, ie the driver selects a new driving step by means of the selector lever, then a control device checks whether the selection is also permissible.

For example, in the selection of the driving position P (parking) it is checked whether the speed of the motor vehicle is less than a limit value. If the selection is permissible, the control device issues a command to a further control device to set the desired drive level. This further control device then controls the actuator so that a selector shaft can be adjusted by means of which different driving steps of the automatic transmission is rotated in a suitable position.

However, especially in fast-changing traffic situations, it can be perceived as disturbing by the driver if, in addition to steering, acceleration and braking of the motor vehicle (motor vehicle), the selector lever is to be operated.

Object of the present invention is to provide a switching method for an automatic transmission of the type mentioned, by means of which switching operations of the automatic transmission by the driver are perceived as particularly ergonomic and pleasant.

This object is achieved by a switching method with the features of claim 1 and by an automatic transmission with the features of claim 5. Advantageous embodiments with expedient developments of the invention are specified in the other claims.

In the switching method according to the invention for an automatic transmission of a motor vehicle, in which the automatic transmission comprises a selector lever, which is used to specify different target states to the automatic transmission by deflection of the selector lever from a center position is initially a specification of the desired states by deflection of the selector lever from its center position. By determining a time frame relevant to the specification of the one target state as a function of at least one operating parameter of the motor vehicle, independently resetting the selector lever to its center position, storing the one desired state during the course of this time span, and converting the one target state into an actual state of the automatic transmission after the time span has elapsed switching operations are perceived by the as particularly ergonomic and pleasant.

The target states correspond to respective driving wishes of the driver, that is, which shift position is to be switched as desired on the automatic transmission. Accordingly, these target states may include the shift positions D (forward drive), N (neutral), R (reverse drive) and P (park the car). A specification of one of these target states to the automatic transmission is now carried out by deflection of the selector lever from its center position. In this case, the driver moves the selector lever in a certain direction until the selector lever abuts in an end position, this end position corresponds to one of the desired states, for example, the driver's desire to move the car forward (D). The driver gets, for example, a haptic feedback, which is that the selector lever can not be moved further in this direction or that the selector lever can be moved when reaching the end position under a modified force. Through this haptic Feedback, it is also conceivable to insert intermediate positions such as individual gears by means of the selector lever. Following the specification of one of the target states, an independent resetting of the selector lever to its center position and the determination of a period of time over which the specification of the desired state is to be maintained. In other words, a period of time is kept open with this time span, via which the driver's intention is to continue to be given to the automatic transmission even after the selector lever has been actuated (and its already returned to its central position). In order to achieve this, the desired state is stored over this period or this period of time and implemented in dependence on an operating parameter of the motor vehicle during this period in the automatic transmission, that is, the desired state corresponding to the driver is converted into an actual state of the automatic transmission, if applicable, with the Operating parameters associated conditions met, or are given. The time span is therefore also determined as a function of at least one such operating parameter since, when the conditions associated with the operating parameter are met, the actual state can be set and thus the further storage of the desired state - during the expiry of the remaining time remaining of the time span - becomes superfluous, why further storage can be discarded. The operating parameter may be, for example, an acceleration value or a speed gradient, but also, for example, a speed threshold or a braking torque limit. Are the associated with the operating parameters conditions, ie z. B. a certain maximum speed value, from which a shift from a forward gear to a reverse gear is possible, not met within the time period, the predetermined target state after the expiration of the period is discarded again, so deleted and therefore no longer maintained. This is z. For example, then the case when the driver has set during a forward drive at high speed for a shift to high speed while engaging the reverse gear as the target state, but then decides to nevertheless not delay his vehicle by braking, or even accelerated. In this case, another operating parameter, for. B. a braking torque curve over time can be used to set both the beginning of the maintenance of the desired state, ie the storage of the desired state, as well as the end of the time period. As an example, a forward drive at a, for a shift in reverse to high speed to call, in which a default of the desired state "reverse" is carried out by the driver. If the driver reaches a certain braking torque limit as the one operating parameter during the subsequent braking of his motor vehicle, then the time period is started, ie the specification of the desired state is maintained. If the driver now lets go of the brake pedal again and thus passes through the braking torque limit again, whereby the time period is ended, although a certain, for the switching process authoritative speed limit has not been reached or exceeded, the stored target state is discarded again.

In summary, the driver can thus, for example, early detection of a parking space - in which he parked backwards - while he is approaching with his car when driving forward the parking space, move the selector lever according to the target state R (reverse drive). This target state R is then maintained after the self-resetting of the selector lever in its central position, so after releasing the selector lever according to the determined period of time until a dependent of one of the operating parameters switching operation can be enabled and the target state accordingly in an actual state can be implemented. In other words, therefore, the desired desired state (R) is maintained until the motor vehicle, for example, as a result of braking when reaching the parking space falls below a speed threshold, from which a conversion of the desired state in the actual state, ie in this case, the insertion of the Reverse gear, possible. The driver can thereby save his shortly following driver's request by deflection of the selector lever particularly early on, and then release the selector lever again, wherein after the expiration of the period, ie upon reaching the operating parameter, the switching operation is implemented by the automatic transmission. Thus, the driver can concentrate on acceleration and deceleration processes and the steering of the motor vehicle and predetermine a target state to the automatic transmission early, which is then implemented as a result of reaching a certain operating parameter of the motor vehicle in the automatic transmission. The driver consequently loses very little time since the desired state remains stored until the actual state can be converted in accordance with the desired state in the automatic transmission as a function of at least one operating parameter.

This is perceived by the driver as being particularly ergonomic, since he is now no longer dependent on the selector lever to be actuated until the motor vehicle is at a standstill, which means that one operating element is less in the chronologically closely spaced sequence of actuation, for example of the steering wheel and the gas and brake pedal for Example when parking must be operated. The desired state, ie the driver's request, is thus extended according to the time span until, when a certain value of at least one of the operating parameters of the motor vehicle is reached, a switching operation is possible. This extension of the time span takes place within the framework of various boundary conditions. Thus, the extension may remain active only as long as a predetermined maximum time has not yet expired (measured from the operation of the selector lever), or as long as the driver has not expressed any other desire (renewed change of direction desired by deflection of the selector lever in an opposite direction ) or as long as the car does not get faster.

Further advantages, features and details of the invention will become apparent from the following description of a preferred embodiment and from the drawings.

These show in:

1a a schematic diagram with a Wählhebelauslenkung by a driver of a motor vehicle over time and thus a specification of a desired state, which in this case corresponds to a shift request of the driver;

1b another schematic diagram of storage of the target state during a period of time, which depends on respective operating parameters;

1c a further schematic diagram showing a switch-on of the automatic transmission, wherein the target state is converted in response to the operating parameters in an actual state and thus in a switching position of the automatic transmission;

1d a further schematic diagram showing the course of a braking torque and a braking torque limit, which is used as an operating parameter for determining the time period;

1e a further schematic diagram showing a speed profile and a speed limit, which is used as another operating parameter for determining the time period;

2a a further schematic diagram with a further Wählhebelauslenkung by the driver of the motor vehicle but the time and thus a further specification of another target state, which in this case corresponds to a further shift request of the driver;

2 B a further schematic diagram showing a further storage of the further target state during a further period of time as a function of respective operating parameters;

2c a further schematic diagram showing a further switch-on, wherein the further target state is converted in response to the operating parameters in a further actual state and thus in a further switching position of the automatic transmission; and in

2d a further schematic diagram showing a further speed curve and a further speed limit, which is used as an operating parameter for determining the further period.

1a to 1e illustrate by way of respective schematic diagrams by way of example individual steps of the switching method for an automatic transmission of a motor vehicle. The car can be both z. B. by means of one or more electric motors, as well as by means of respective internal combustion engines (diesel engine, gasoline engine), or are driven by a hybrid drive. 2a to 2d illustrate another switching operation as an example of this switching method. Identical and functionally identical elements are provided with the same reference numerals. All figures comprise as abscissa a time axis 20 ,

In 1a is a selector lever deflection 18 over the timeline 20 shown. Without deflection by a driver sitting in the car, a selector lever, not shown here, is in a middle position 12 , wherein the selector lever by the driver also according to a deflection 10 (Reverse, R) or according to a deflection 14 (Forward drive; D) can be deflected. As in 1a can be seen, there is a deflection in the present case 10 of the selector lever from its center position 12 and thus a requirement 13 a desired state 15 , In other words, therefore, by the deflection 10 the default 13 a desired reverse drive, which present here as the desired state 15 is transmitted to a not shown here control unit of the motor vehicle.

1b shows in a schematic diagram in which a driver request storage 30 of - as in 1a explained - predetermined target state 13 in the control unit (ECU), not shown here. As part of the driver request storage 30 can optionally be reversed in the control unit 32 , a forward drive 34 or maintaining the currently prevailing state as the ground state 36 get saved. According to the already with reference to 1a explained specification 13 the target state 15 will, as in 1b recognizable, essentially at the same time as the specification 13 by selector lever deflection 18 by the driver the driver's request after the reverse drive 32 stored in the control unit (ECU). With the storage of the specification 13 the target state 15 also begins a lapse of a period of time 22 , The length of the time span 22 Depends on at least one operating parameter of the motor vehicle. In this example, with a braking torque 50 , which is ordinate in 1d is applied, or a braking torque curve 52 and at a speed 70 , which as ordinate in 1e is applied, or a velocity profile 72 even specified several operating parameters of the motor vehicle, of which the time span 22 , or the duration of the period 22 depends.

In the representation of the braking torque 50 over the timeline 20 in 1d is also a braking torque limit 54 applied. As in 1a can be seen results in the illustrated braking torque curve 52 an intersection with the braking torque limit 54 , where initially a trigger signal through this point of intersection 64 the time span is used 22 to activate and accordingly the target state 15 over the duration of the deflection 10 ( 1a ) of the selector lever and thus keep active. In other words, therefore, the specified by previous deflection target state 15 of the selector lever over the period of time 22 stored, with the time span 22 from the braking torque curve 52 as one of the operating parameters depends. The timespan 22 is now kept active for so long, so the target state 15 stored until the braking torque limit 54 , which also corresponds to one of the operating parameters, again by the braking torque curve 52 is cut. In other words, the time span 22 when exceeding the braking torque limit 54 through the braking torque curve 52 extended as long as the brake torque curve 52 above the braking torque limit 54 is and accordingly, until the braking torque curve 52 the braking torque limit 54 again cuts. This re-cutting will give another trigger signal 66 triggered, based on which the time span 22 limited and thus terminated. By means of the trigger signal 64 Thus, the controller first causes the time period 22 , about which the nominal state 15 maintained, so is stored, remains activated, and by the trigger signal 66 will be the time span 22 finally finished.

The in 1e above the speed 70 plotted velocity course 72 is now used to fall below a speed limit 74 another trigger signal 68 to transmit to the controller, using the trigger signal 68 as part of an in 1c shown switch-on process 38 a conversion of the nominal state 15 in an actual state 40 he follows. Cuts the speed history 72 So the speed limit 74 , which as a threshold or speed threshold for the switch-on 38 serves, during the time span 22 , ie in a temporal section between the trigger signal 64 and the trigger signal 66 , then a conversion of the desired state takes place 15 , So the driver's request in the actual state 40 , The speed course 72 as well as the speed limit 74 also serve as each one of the operating parameters. By converting the target state 15 in the actual state 40 Thus, a corresponding gear is engaged in the automatic transmission, this gear in the present example for reversing 32 serves. Would the speed course 72 with the speed limit 74 outside the time span 22 cut, so would the nominal state 15 , So the driver's request, be discarded and, accordingly, no implementation of the target state 15 in the actual state 40 respectively. It is clear that the speed limit 74 taking into account respective ratios of the drive train or the gear ratios of the transmission and a speed threshold of a motor vehicle driving engine (internal combustion engine, electric motor) may correspond. In other words, as one of the operating parameters of which the time period 22 depends also the speed threshold be used. As soon as the speed gradient 72 and the speed limit 74 after the beginning of the time span 22 , So transmitting the trigger signal 64 cut to the control unit, with the time of this cut also the time span 22 terminated because the switching process is thus enabled (implementation of the desired state 15 in the actual state 40 ) and saving is no longer necessary.

From the synopsis of 2a to 2d it can be seen that a speed gradient can also be used as one of the operating parameters. 2a to 2d In the present case, only some excerpts are to be presented, since essential components are already explained on the basis of the explanatory notes to the 1a to 1e have been described.

As in 2d is recognizable, in this example, both the velocity profile 72 , as well as its intersection with the speed limit 74 to extend the time span 22 or to implement the desired state 15 in the actual state 40 used. The speed course 72 and in particular a speed gradient, ie the temporal change of the speed profile 72 , are used to activate a trigger signal 60 , on the basis of which the Period of time 22 is extended, used. The timespan 22 So in the present case remains active until - as already on the basis of 1e described - the speed distribution 72 the speed limit 74 cuts and thereby a trigger signal 62 is activated. In contrast to the example, which is based on 1a to 1e has been explained, here serves the course of the speed 72 , as well as its derivative by time (velocity gradient) both on the one hand to start storage over the period 22 , as well as to trigger the switch-on 38 the actual state 40 and associated with ending the time span 22 , about which the nominal state 15 should be saved. At the present velocity gradient, a deceleration (negative slope of the velocity profile 72 ) and thereby triggering the time span 22 , ie saving the desired state 15 activated.

LIST OF REFERENCE NUMBERS

10

Deflection (R)

12

center position

13

specification

14

Deflection (D)

15

target state

18

Wählhebelauslenkung

20

timeline

22

Period of time

30

Driver's desired storage

32

reversing

34

driving forward

36

ground state

38

switch-on

40

It's on

50

braking torque

52

Braking torque path

54

Braking torque limit

60

trigger signal

62

trigger signal

64

trigger signal

66

trigger signal

68

trigger signal

70

speed

72

speed curve

74

speed limit

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 202004019677 U1 [0002]

Claims (5)

Shifting method for an automatic transmission of a motor vehicle, in which the automatic transmission comprises a selector lever, which according to the specification ( 13 ) of different nominal states ( 15 ) to the automatic transmission by deflection ( 10 . 14 ) of the selector lever from a middle position ( 12 ), with the steps: - Specification of one of the desired states ( 15 ) by deflection ( 10 . 14 ) of the selector lever from its middle position ( 12 ), - determining a default ( 13 ) of a desired state ( 15 ) ( 22 ) depending on at least one operating parameter of the motor vehicle, - independent resetting of the selector lever in its center position ( 12 ), - storing the one desired state ( 15 ) during the expiration of this period ( 22 ), and - implementing the one desired state ( 15 ) into an actual state ( 40 ) of the automatic transmission at the end of the time span ( 22 ). Switching method according to claim 1, characterized in that as the at least one operating parameter, a speed gradient is used. Switching method according to claim 1, characterized in that as the at least one operating parameter, a speed threshold is used. Switching method according to claim 1, characterized in that as the at least one operating parameter a braking torque limit ( 54 ) is used. Automatic transmission of a motor vehicle, with an independent in a middle position ( 12 ) resetting selector lever, by the deflection ( 10 . 14 ) around the middle position ( 12 ) different nominal states ( 15 ) of the automatic transmission, characterized in that at least one predetermined by previous deflection target state ( 15 ) in the subsequent middle position ( 12 ) of the selector lever over a time dependent on at least one operating parameter of the motor vehicle ( 22 ) is stored.

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