Method and control unit for operating a motor vehicle

Abstract

A method for operating a motor vehicle (10) comprising a drive unit (11) and a transmission (13) with at least one positive-locking switching element (14) connected between the drive unit (11) and an output (12), wherein, when a shift is to be performed in the transmission (13) for which a positive-locking switching element (14) is to be closed, synchronization is carried out for the switching element (14) to be closed, and subsequently, the same is actuated to close. During the synchronization of the positive-locking switching element (14) to be closed, at least one transmission input speed and one transmission output speed are monitored as operating parameters.During synchronization, actual values ​​of the monitored operating parameters are compared with values ​​from predefined sets of operating parameters for which a tooth-to-tooth position on the switching element (14) to be closed is likely and / or for which a tooth-to-tooth position has already formed on the switching element (14) to be closed. If no match is found between the actual values ​​and the values ​​of the predefined operating parameter sets, the switching element (14) is immediately activated to close. If a match is found between the actual values ​​and the values ​​of one of the predefined operating parameter sets, the switching element (14) is only activated to close after a workaround has been executed.

Description

[0001] The invention relates to a method for operating a motor vehicle. It further relates to a control unit for operating a motor vehicle.

[0002] A motor vehicle typically has a transmission positioned between the engine and an output shaft. The transmission converts speed and torque and delivers the tractive force from the engine to the vehicle's output shaft.

[0003] A motor vehicle transmission has several shifting elements. In each friction-based gear, a first set of shifting elements is closed and a second set of shifting elements is open. To shift gears in a transmission, at least one previously closed shifting element is opened and at least one previously open shifting element is closed. The shifting elements of a transmission can be friction-based or positive-locking. Friction-based shifting elements include clutches and brakes. Positive-locking shifting elements include dog clutches.

[0004] When a positive-locking switching element is closed to execute a shift in a transmission, a tooth-on-tooth alignment can develop on the positive-locking switching element. Such a tooth-on-tooth alignment leads to increased wear in the transmission.

[0005] DE 10 2013 218 426 A1 discloses a method which serves to resolve a tooth-on-tooth position that has formed on a positive locking switching element.

[0006] There is a need to reduce the number of tooth-to-tooth positions that form on positive-locking switching elements, so that less wear occurs in a gearbox and fewer tooth-to-tooth positions have to be resolved.

[0007] The object of the present invention is to provide a method for operating a motor vehicle and a control unit for carrying out the method, with the aid of which the number of tooth-on-tooth positions forming on positive locking switching elements can be reduced.

[0008] This problem is solved by a method for operating a motor vehicle according to claim 1 and by a control unit for operating a motor vehicle according to claim 7.

[0009] According to the invention, during the synchronization of the positive-locking switching element to be closed, at least one gearbox input speed or a speed corresponding to the gearbox input speed and one gearbox output speed or a speed corresponding to the gearbox output speed are monitored as operating parameters.

[0010] Furthermore, according to the invention, during the synchronization of the positive-locking switching element to be closed, actual values ​​of the monitored operating parameters are compared with values ​​of predetermined operating parameter sets for which a tooth-to-tooth position on the positive-locking switching element to be closed is probable and / or has already formed a tooth-to-tooth position on the positive-locking switching element to be closed.

[0011] Then, if no agreement is found between the actual values ​​of the monitored operating parameters and the values ​​of the specified operating parameter sets, the positive-locking switching element to be closed is directly controlled according to the invention.

[0012] Then, if a match is found between the actual values ​​of the monitored operating parameters and the values ​​of one of the specified sets of operating parameters, the positive-locking switching element to be closed is only activated after a bypass measure has been carried out, according to the invention.

[0013] The invention makes it possible to reduce the number of tooth-on-tooth positions that develop in a gearbox during the operation of the motor vehicle, and thus also to reduce wear in the gearbox.

[0014] Preferably, during the synchronization of the positive-locking switching element to be closed, synchronization parameters of the positive-locking switching element to be closed are also monitored as operating parameters. These parameters include a synchronization differential speed and a synchronization time, and in particular also a road inclination on which the vehicle is operated when the shifting is performed and thus when the respective positive-locking switching element is closed. This is particularly preferred in order to reduce the number of tooth-on-tooth positions that form in the transmission and thus also the wear of the transmission.

[0015] Preferably, if during the synchronization of the positive-locking switching element to be closed a match is found between the actual values ​​of the monitored operating parameters and the values ​​of one of the specified operating parameter sets, as a workaround measure the actuation of the positive-locking switching element to be closed is delayed until no match is found between the actual values ​​of the monitored operating parameters and the values ​​of the specified operating parameter sets or until the synchronization time is exceeded.If, during the synchronization of the positive-locking switching element to be closed, a match is detected between the actual values ​​of the monitored operating parameters and the values ​​of one of the predefined sets of operating parameters, and if a delay in actuating the positive-locking switching element to close leads to an exceeding of the synchronization time, a new synchronization with new synchronization parameters is performed as a workaround. These workarounds can advantageously reduce the number of tooth-to-tooth positions that develop in the transmission of a motor vehicle during operation, and thus also the wear in the transmission.

[0016] Preferably, when the positive-locking switching element to be closed is actuated, either directly or after a bypass measure has been executed, it is monitored whether a tooth-on-tooth position develops on the positive-locking switching element to be closed. If a tooth-on-tooth position is detected, the actual values ​​of the operating parameters valid at the time the positive-locking switching element to be closed are stored in an operating parameter set as values ​​for which the tooth-on-tooth position has developed on the positive-locking switching element to be closed. This also serves to reduce the number of tooth-on-tooth positions that develop and thus the wear in the gearbox.

[0017] Preferred embodiments are described in the dependent claims and the following description. Exemplary embodiments of the invention are explained in more detail with reference to the drawing, without being limited thereto. The drawing shows: Fig. 1 a schematic representation of a motor vehicle, Fig. 2. A block diagram to illustrate the invention.

[0018] Fig. Figure 1 shows a highly schematic representation of a possible powertrain configuration for a motor vehicle. Figure 10 shows Fig. 1. A motor vehicle 10 with a drive unit 11 and a transmission 13 connected between the drive unit 11 and an output 12. The drive unit 11 can be an internal combustion engine, an electric motor, or a drive unit of a hybrid vehicle, which includes both an internal combustion engine and an electric motor. The transmission 13 converts rotational speeds and torques and makes the tractive force of the drive unit 11 available at the output 12.

[0019] The gearbox 13 has several shift elements, with in Fig. Figure 1 shows an exemplary positive-locking switching element 14. Such a positive-locking switching element 14 can be a claw. In addition to at least one positive-locking switching element 14, the transmission can also have at least one friction-locking switching element.

[0020] In each current gear of the transmission 13, a first number of shift elements are closed and a second number of shift elements are open. If a gear change from a current gear to a target gear is to be performed, at least one shift element that was closed in the current gear is opened and at least one shift element that was open in the current gear is closed.

[0021] Fig. Figure 1 further shows an engine control unit 15 for controlling and / or regulating the operation of the drive unit 11 and a transmission control unit 16 for controlling and / or regulating the operation of the transmission 13. According to Fig. 1. The engine control unit 15 exchanges data with the drive unit 11, and the transmission control unit 16 exchanges data with the transmission 13. Furthermore, the engine control unit 15 and the transmission control unit 16 exchange data with each other.

[0022] The positive locking switching element 14 is assigned a position sensor 17, which can be used to monitor whether the positive locking switching element 14 is closed, open or in a tooth-to-tooth position.

[0023] As already explained, the in Fig. The powertrain configuration shown in Figure 10 is exemplary. The vehicle may also have a different powertrain configuration.

[0024] As already explained, when a gear shift is to be performed in the transmission 13, at least one previously opened shift element is closed. The present invention relates to a method for operating a motor vehicle in which a positive-locking shift element 14 of the transmission 13 is to be closed for the purpose of performing a gear shift. If a previously opened positive-locking shift element 14 is to be closed for the execution of a gear shift in the transmission 13, synchronization is performed for the positive-locking shift element 14, and subsequently the positive-locking shift element 14 to be closed is actuated.

[0025] It is known from practical experience that a tooth-on-tooth alignment can occur when a positive-locking switching element 14 is closed. The present invention aims to reduce the number of tooth-on-tooth alignments that may occur when a positive-locking switching element 14 is closed, thereby reducing wear in the transmission 13.

[0026] In accordance with the invention, during the synchronization of the positive-locking switching element 14 to be closed, at least one gearbox input speed or a speed corresponding to the gearbox input speed or a gearbox output speed or a speed corresponding to the gearbox output speed is monitored as an operating parameter.

[0027] During the synchronization of the positive-locking switching element 14 to be closed, actual values ​​of the monitored operating parameters are compared with values ​​of predefined operating parameter sets for which a tooth-to-tooth position on the positive-locking switching element 14 to be closed is probable and / or for which a tooth-to-tooth position has already formed on the positive-locking switching element 14 to be closed.

[0028] Then, if no match is found between the actual values ​​of the monitored operating parameters and the values ​​of the specified operating parameter sets, the positive-locking switching element 14 to be closed is immediately activated to close.

[0029] However, if a match is found between the actual values ​​of the monitored operating parameters and the values ​​of one of the specified sets of operating parameters, the positive-locking switching element 14 to be closed will only be activated after a bypass measure has been carried out.

[0030] The invention can counteract the formation of tooth-on-tooth positions on a positive-locking switching element 14 to be closed, thus reducing wear in the gearbox 13.

[0031] Further details of the invention are described below with reference to the block diagram of the Fig. 2 described. A block 20 of the Fig. 2 visualizes a start of the inventive method and block 44 an end of the same.

[0032] After the inventive method according to block 20 is started, an input signal 40, corresponding to a received control signal for executing a gear change in the transmission 13, is processed in a block 21. If a gear change is to be executed in the transmission 13, actual values ​​of monitored operating parameters are compared in a block 22 with values ​​of predefined sets of operating parameters for which a tooth-to-tooth position on the positive-locking switching element 14 to be closed is probable and / or for which a tooth-to-tooth position has already formed on the positive-locking switching element 14 to be closed.

[0033] The actual values ​​of the monitored operating parameters are monitored in block 23 and provided to block 22 from block 23. According to Fig. 2. As operating parameters, at least one gearbox input speed 24 and / or a speed corresponding to gearbox input speed 24 and one gearbox output speed 25 or a speed corresponding to gearbox output speed 25 are monitored, namely, actual values ​​of these speeds are recorded. Further operating parameters are listed in Fig.Two synchronization parameters 26 and a road gradient 27, on which the motor vehicle is operated, are monitored. Actual values ​​of the monitored operating parameters 24, 25, 26, and 27 are determined in block 23 and provided to block 22. In block 22, the actual values ​​of the monitored operating parameters 24 to 27 are compared with values ​​of predefined parameter sets 28, whereby the values ​​of predefined parameter sets are provided by a memory. The memory contains predefined values ​​of operating parameter sets for which a tooth-to-tooth position on the positive-locking switching element 14 to be closed is probable and / or for which a tooth-to-tooth position has already formed on the positive-locking switching element 14 to be closed.

[0034] Then, if block 29 detects a discrepancy between the actual values ​​of the monitored operating parameters 24, 25, 26, 27 and the values ​​of the predefined operating parameter sets 28, the process branches from block 29 to block 30. In block 30, the positive-locking switching element 14 is directly activated for closing. In block 31, it is checked whether a tooth-to-tooth position is formed on the positive-locking switching element 14 when it closes. If block 31 detects that a tooth-to-tooth position is not formed on the positive-locking switching element 14, the process branches from block 31 to block 32. In block 32, it is determined that the positive-locking switching element 14 was successfully closed.

[0035] If, however, it is determined in block 31 that a tooth-to-tooth position has formed on the positive-locking switching element 14 controlled for closing, then a branch is made from block 31 to block 33, whereby a tooth-to-tooth position is then recognized in block 33 and in a subsequent block 34 those actual values ​​of the operating parameters are stored as values ​​in an operating parameter set 28 for which the tooth-to-tooth position has formed on the positive-locking switching element 14 to be closed.

[0036] Then, if in block 29 a match is found between the actual values ​​of the monitored operating parameters 24, 25, 26 and 27 provided by block 23 and the values ​​of the predefined operating parameter sets 28, the process branches from block 29 to block 35. In block 35, direct activation of the positive-locking switching element 14 to close is prevented.

[0037] In block 36, it is checked whether, as a workaround, the actuation of the positive-locking switching element 14 to be closed can be delayed without exceeding a permissible synchronization time duration, which is part of the monitored synchronization parameters 26.

[0038] If this is the case, i.e., the actuation of the positive-locking switching element 14 to be closed can be delayed without exceeding the synchronization time, then the process branches from block 36 to block 37, whereby in block 37 the actuation of the positive-locking switching element 14 to be closed is delayed until there is no longer any agreement between the actual values ​​of the monitored operating parameters and the values ​​of the specified parameter sets or until the synchronization time is exceeded.

[0039] If block 36 detects that the delay in controlling the positive-locking switching element 14 to close leads to an exceeding of the synchronization time, the system branches from block 36 to block 38, generating an output signal 39 in block 38, which, as a workaround, requests a new synchronization with new synchronization parameters, such as a new synchronization differential speed and / or a new synchronization time.

[0040] As already explained, block 31 checks whether a tooth-to-tooth position is formed on a positive-locking switching element 14 that is controlled for closing. This can be done, for example, by evaluating a position signal from the position sensor 17 assigned to the positive-locking switching element 14.

[0041] As previously explained, when block 31 detects that a tooth-to-tooth position has formed on the positive-locking switching element 14, which is controlled for closing, the process branches from block 31 to block 33. In block 33, a tooth-to-tooth position is detected, and in a subsequent block 34, the respective actual values ​​of the operating parameters are stored in an operating parameter set 28. From block 33, the process branches not only to block 34 but also to block 41. In block 41, it is checked whether there is still sufficient time for the tooth-to-tooth position to resolve within the synchronization period.

[0042] If block 41 determines that there is insufficient time to resolve the tooth-on-tooth misalignment within the synchronization period, the process branches from block 41 to block 38. Conversely, if block 41 determines that there is sufficient time to resolve the tooth-on-tooth misalignment within the synchronization period, the process branches from block 41 to block 42, where measures to resolve the tooth-on-tooth misalignment are implemented. For example, electromechanical actuators can be used in block 42 to resolve the tooth-on-tooth misalignment.

[0043] In block 43, it is subsequently checked whether the tooth-to-tooth alignment could be resolved, i.e., whether the circuit could be successfully completed. If block 43 determines that the tooth-to-tooth alignment could be resolved, i.e., that the circuit could be successfully completed, then the logic branches from block 43 to block 32. If, however, block 43 determines that the tooth-to-tooth alignment could not be resolved, i.e., that the circuit could not be successfully completed, then the logic branches from block 43 to block 38.

[0044] If, for example, the positive locking switching element 14 is controlled to close by an electric motor, the signal of the sensor 17 can be evaluated together with a current value of the electric motor that takes over the control of the positive locking switching element 14.

[0045] With pneumatic actuation of the positive locking switching element 14, the position signal of the sensor 17 can be evaluated together with a time sequence condition.

[0046] The invention further relates to a control unit configured to automatically execute the method described above. This control unit is, in particular, an electronic control unit that has hardware and software means for carrying out the method according to the invention.

[0047] Hardware components include data interfaces for exchanging data with the assemblies involved in carrying out the method according to the invention, for example with sensor 17. Hardware components also include a memory for data storage and a processor for data processing.

[0048] The software-related means include program modules that are implemented in the control unit for carrying out the method according to the invention. The control unit according to the invention can, for example, be the transmission control unit 16.

[0049] The control unit according to the invention is designed to monitor, as operating parameters during the synchronization of the positive-locking switching element 14 to be closed, at least the transmission input speed 24 or a speed corresponding to the transmission input speed 24 and the transmission output speed 25 or a speed corresponding to the transmission output speed 25, preferably also the synchronization parameters 26 and the road inclination 27.The control unit according to the invention is further configured to compare actual values ​​of the monitored operating parameters 24, 25, 26, 27 with values ​​of predefined parameter sets, which are stored in particular in memory 28, during the synchronization of the positive locking switching element 14 to be closed, namely such parameter sets for which a tooth-to-tooth position on the positive locking switching element 14 to be closed is probable and / or for which a tooth-to-tooth position has already formed on the positive locking switching element 14 to be closed.

[0050] Furthermore, the control unit according to the invention is configured to directly activate the positive locking switching element 14 to close if no agreement is found between the actual values ​​of the monitored operating parameters 24, 25, 26, 27 and the values ​​of the predetermined operating parameter sets of block 28.

[0051] However, if a match is found between the actual values ​​of the monitored operating parameters 24, 25, 26, 27 and the values ​​of one of the specified operating parameter sets of block 28, the control unit according to the invention is configured to activate the positive locking switching element 14 to close only after a bypass measure of blocks 35, 36, 37 and 38 has been executed.

[0052] The invention makes it possible to reduce the number of tooth-on-tooth positions forming in a gearbox 13 on positive-locking switching elements 14 and thus also to protect the gearbox 13 from wear as a result of such tooth-on-tooth positions. Reference sign 10 motor vehicle 11 Drive unit 12 Drive 13 gearboxes 14 positive-locking switching elements 15 Engine control unit 16 Transmission control unit 17 Sensor 20 Start 21 Input signal processing 22 Value comparison 23 Operating parameter monitoring 24 operating parameters, gearbox input speed 25 operating parameters, gearbox output speed 26 operating parameters, synchronization parameters 27 Operating parameters, road gradient 28 parameter sets 29 Value comparison review 30 Locking control 31 Tooth-to-tooth alignment check 32 Closing detection 33 Tooth-on-tooth alignment detection 34 Operating parameter set storage 35 Suppression of locking control 36 Synchronization timeout check 37 Delay in closing control 38 Output signal generation 39 Output signal synchronization request 40 Input signal 41 Time check 42 Tooth-on-tooth alignment resolution 43 Resolution check 44 End QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2013 218 426 A1

[0005]

Claims

[1] Methods for operating a motor vehicle (10), wherein the motor vehicle (10) has a drive unit (11) and a transmission (13) with at least one positive-locking switching element (14) shifted between the drive unit (11) and an output (12), wherein, when a switching operation is to be carried out in the transmission (13) for which a positive-locking switching element (14) is to be closed, a synchronization is carried out for the positive-locking switching element (14) to be closed and subsequently the positive-locking switching element (14) to be closed is controlled for closing, characterized by , that During the synchronization of the positive-locking switching element (14) to be closed, at least one gearbox input speed or a speed corresponding to the gearbox input speed and one gearbox output speed or a speed corresponding to the gearbox output speed are monitored as operating parameters. During the synchronization of the positive-locking switching element (14) to be closed, actual values ​​of the monitored operating parameters are compared with values ​​of predefined sets of operating parameters for which a tooth-to-tooth position on the positive-locking switching element (14) to be closed is probable and / or for which a tooth-to-tooth position has already formed on the positive-locking switching element (14) to be closed. Then, if no agreement is found between the actual values ​​of the monitored operating parameters and the values ​​of the specified operating parameter sets, the positive locking switching element (14) to be closed is immediately activated to close, Then, if a match is found between the actual values ​​of the monitored operating parameters and the values ​​of one of the specified sets of operating parameters, the positive locking switching element (14) to be closed is only activated after a bypass measure has been carried out. [2] Method according to claim 1, characterized by , that during the synchronization of the positive-locking switching element (14) to be closed, synchronization parameters are also monitored as operating parameters, which include a synchronization differential speed and a synchronization time duration. [3] Method according to claim 1 or 2, characterized by, that if a match is found between the actual values ​​of the monitored operating parameters and the values ​​of one of the specified sets of operating parameters, as a workaround measure the actuation of the positive locking switching element (14) to be closed is delayed until no match is found between the actual values ​​of the monitored operating parameters and the values ​​of the specified sets of operating parameters or until the synchronization time is exceeded. [4] Method according to claim 3, characterized by , that if a match is found between the actual values ​​of the monitored operating parameters and the values ​​of one of the specified sets of operating parameters, and if a delay in actuating the positive locking switching element (14) to close leads to exceeding the synchronization time duration, a new synchronization is carried out with new synchronization parameters. [5] Method according to any one of claims 1 to 4, characterized by , that when the positive locking switching element (14) to be closed is activated for closing, it is monitored whether a tooth-on-tooth position is formed on the positive locking switching element (14) to be closed, and if it is determined that a tooth-on-tooth position is formed on the positive locking switching element (14) to be closed, the actual values ​​of the operating parameters valid when the positive locking switching element (14) to be closed is activated are stored in an operating parameter set as values ​​for which a tooth-on-tooth position has formed on the positive locking switching element (14) to be closed. [6] Method according to any one of claims 1 to 5, characterized by, that during the synchronization of the positive-locking switching element (14) to be closed, a road inclination in which the motor vehicle is operated is also monitored as an operating parameter. [7] Control unit for operating a motor vehicle (10), wherein the motor vehicle (10) has a drive unit (11) and a transmission (13) with at least one positive-locking switching element (14) shifted between the drive unit (11) and an output (12), wherein the control unit then, when a switching operation is to be carried out in the transmission (13) for which a positive locking switching element (14) is to be closed, performs a synchronization for the positive locking switching element (14) to be closed and subsequently controls the positive locking switching element (14) to be closed, characterized by , that the control unit monitors at least one transmission input speed or a speed corresponding to the transmission input speed and one transmission output speed or a speed corresponding to the transmission output speed as operating parameters during the synchronization of the positive locking switching element (14) to be closed, The control unit compares actual values ​​of the monitored operating parameters with values ​​of predefined operating parameter sets during the synchronization of the positive-locking switching element (14) to be closed, for which a tooth-to-tooth position on the positive-locking switching element (14) to be closed is probable and / or has already formed a tooth-to-tooth position on the positive-locking switching element (14) to be closed. The control unit then, if no match is found between the actual values ​​of the monitored operating parameters and the values ​​of the specified operating parameter sets, immediately activates the positive-locking switching element (14) to close, and then, if a match is found between the actual values ​​of the monitored operating parameters and the values ​​of one of the specified operating parameter sets, activates the positive-locking switching element (14) to close only after a workaround measure has been carried out. [8] Control unit according to claim 7, characterized by that the control unit is configured to automatically execute the method according to any one of claims 1 to 6.

Images