Method and control device for operating a drive train

Abstract

A method for operating a drive system of a motor vehicle, the drive system comprising: a drive unit (1); a group transmission (2) with sub-transmissions; and a disengagement clutch (5) connected between the drive unit and the group transmission, wherein if the speed becomes less than a threshold value, the disengagement clutch (5) is disengaged and one of the sub-transmissions is shifted to neutral for transmission pre-selection, and the other sub-transmissions or each of the other sub-transmissions is shifted to a force-locked state, wherein the disengagement clutch (5) is then at least partially closed and the drive unit (1) is brought to a defined speed, wherein a starting shift is then checked when the group transmission (2) requires force-locked engagement. If the driver expects to shift gears, then if the driver expects to shift gears, then it is checked whether the target speed of the drive unit (1) is greater than or less than the current input speed of the group transmission. If there is a starting shift and if the target speed of the drive unit (1) is less than the current input speed of the group transmission when the driver expects to shift gears, then the disengagement clutch (5) is disengaged and the sub-transmission in neutral is synchronized by the transmission brake (4). If the target speed of the drive unit (1) is greater than the current input speed of the group transmission (2) when the driver expects to shift gears, then the sub-transmission in neutral is synchronized by the drive unit (1).

Description

Technical Field

[0001] This invention relates to a method for operating a drive system of a motor vehicle, wherein the drive system has a drive unit, a group transmission connected between the drive unit and an output end, and a disengagement clutch connected between the drive unit and the group transmission, and wherein the group transmission has a plurality of sub-transmissions, namely at least one main transmission and an auxiliary transmission that is technically connected before the main transmission and / or a range gear group that is technically connected after the main transmission. The invention also relates to a control device for operating such a drive system. Background Technology

[0002] Drive systems for motor vehicles are known from the prior art, and these drive systems have grouped transmissions as transmissions. A grouped transmission has a main transmission, a secondary transmission that is technically preceding the main transmission, and / or a range of gears that is technically following the main transmission. The main transmission is also referred to as the main gear group. DE 10 2007 007 257 A1 discloses the use of an electric motor as a synchronizing mechanism during gear shifting in a grouped transmission.

[0003] If a motor vehicle with a group transmission decelerates, i.e., slows down, the disengagement clutch disengages below a certain threshold speed, thus disengaging the drive unit from the transmission. If the group transmission is to be transitioned to a force-lock state from this state—more precisely, either during a starting shift or a driver-desired shift—a long synchronization time can occur, and the transition to force-lock can therefore take a considerable amount of time. This is because the input shaft of the group transmission disengages when the disengagement clutch is engaged and there is no force-lock. This long synchronization time in a group transmission leads to a decrease in comfort.

[0004] It is necessary to synchronize the group transmissions more quickly and thus enable them to transition from a non-force-locked state to a force-locked state more quickly.

[0005] DE 10 2007 012 875 A1 discloses a method for operating a drive system in which, if a motor vehicle is rolling with the starting clutch disengaged, a gear is shifted in the transmission to match the current speed of the motor vehicle so as to provide a gear matching the speed of the motor vehicle present when the starting clutch is subsequently engaged.

[0006] DE 10 2007 010 295 A1 discloses another method for operating a drive system of a motor vehicle, namely, for performing so-called coasting shifting during coasting of a motor vehicle. Summary of the Invention

[0007] Therefore, the objective of this invention is to provide a new method for operating a drive system of a motor vehicle and a control device for performing the method.

[0008] This task is solved by the method for operating the drive system according to the present invention.

[0009] If the speed of the vehicle becomes less than the boundary value, the disengagement clutch is disengaged and, for transmission preselection, one of the sub-transmissions is shifted to neutral or toward neutral, and the other sub-transmissions or each of the other sub-transmissions is shifted to force-locked or toward force-locked.

[0010] Subsequently, the disengagement clutch is at least partially engaged, and the drive unit is brought to a specified speed.

[0011] Subsequently, it was examined whether the shift was initiated or the driver desired to shift in the case of a group transmission requiring force lock-in.

[0012] If the driver expects a gear shift to be requested, check whether the target speed of the drive unit is greater than or less than the current input speed of the group transmission.

[0013] If a shift is requested to initiate a gear change, and if the target speed of the drive unit is less than the current input speed of the group transmission when a shift is requested by the driver, the disengagement clutch is disengaged, the sub-transmission in neutral is synchronized via the transmission brake, and after synchronization, the sub-transmission is switched to a force-lock state. If the target speed of the drive unit is greater than the current input speed of the group transmission when a shift is requested by the driver, the drive unit synchronizes the sub-transmission in neutral, and after synchronization, the sub-transmission is switched to a force-lock state.

[0014] The method according to the invention proposes that when the speed of the motor vehicle is less than a boundary value, if the disengagement clutch is disengaged and if one of the sub-transmissions of the group transmission is shifted to neutral or toward neutral, while the other sub-transmissions or each of the other sub-transmissions of the group transmission is shifted to a force-locked state or toward a force-locked state, then at least partially disengage the disengagement clutch and bring the drive unit to a defined speed, and then check whether the group transmission can be shifted to a force-locked state when performing a starting shift or when performing a shift desired by the driver. Based on this, defined synchronization of the sub-transmissions of the group transmission in neutral is achieved, and then that sub-transmission, and subsequently the entire group transmission, is shifted to a force-locked state. With the invention, it is possible to shorten the time required for the group transmission to shift from a non-force-locked state to a force-locked state. In the case of starting a shift while the motor vehicle is stationary, tooth-to-tooth positioning at the shift elements of the group transmission can be prevented.

[0015] Preferably, to check whether a start-up shift is required in the case of a force-locked transmission, the current speed of the vehicle is checked to see if it is less than a second boundary value, wherein if the current speed of the vehicle is less than the second boundary value, a start-up shift is required. Preferably, to check whether a driver-desired shift for the transmission is required in the case of a force-locked transmission, in addition to checking the speed of the vehicle, the operation of the accelerator pedal and / or the brake pedal on the driver's side is also checked, wherein if the current speed of the vehicle is greater than the second boundary value, and further if the brake pedal is no longer operated on the driver's side and / or the accelerator pedal is operated on the driver's side, a driver-desired shift is required. This method is particularly suitable for checking whether a transmission is switched to a force-locked state when a start-up shift is performed or when a driver-desired shift is performed.

[0016] Preferably, if the driver expects a gear shift to be requested, the target gear of the grouped transmission is determined based on the current driving conditions of the vehicle, and the target speed of the drive unit is determined based on the target gear. After determining the target gear, it is checked whether the pre-selected transmission matches the target gear. If it is confirmed that the pre-selected transmission does not match the target gear, the method is terminated; if it is confirmed that the pre-selected transmission matches the target gear, the method is not terminated. This allows for further improvement of the method.

[0017] This task is also solved by the control device according to the invention. Attached Figure Description

[0018] Preferred extensions are derived from the following description. Embodiments of the invention are described in more detail with reference to the accompanying drawings without limitation. Hereinafter:

[0019] Figure 1 An exemplary design for a drive system of a motor vehicle is shown; and

[0020] Figure 2 A signal flow diagram is shown to illustrate the present invention. Detailed Implementation

[0021] The present invention relates to a method for operating a drive system of a motor vehicle and a control device for performing the method.

[0022] Figure 1 A schematic diagram of a drive system for a motor vehicle is shown, which includes a drive unit 1, a group transmission 2, and an output terminal 3.

[0023] The drive unit 1 can be coupled to the input shaft 6 of the group transmission 2 via a disengagement clutch 5, which is also called a starting clutch. The output end 3 is coupled to the output shaft 8 of the group transmission 2.

[0024] In the illustrated embodiment, the grouped transmission 2 includes: a main transmission 9; a secondary transmission 10 driven before the main transmission 9; and a range gear group 11 driven after the main transmission 9. In addition to the main transmission 9, only the range gear group 11 or only the secondary transmission 10 may exist. The main transmission 9 is also referred to as the main gear group.

[0025] The main transmission 9 of the group transmission 2 is implemented as a direct-drive transmission with an intermediate shaft structure and has two intermediate shafts 21 and 22.

[0026] In the illustrated embodiment, the main transmission 9 is designed to have three drive stages G1, G2, and G3 for forward travel and one drive stage R for backward travel. The chuck gears of drive stages G1, G2, and R are rotatably mounted on the main shaft and can be switched via assigned shift elements 15, 16, 18, and 19, which are designed as dog clutches. Assigned fixed gears are arranged on intermediate shafts 21 and 22 in a manner resistant to relative rotation. Two shift elements 15 and 16 and two shift elements 18 and 19 respectively form a shift assembly 17 or 20. The main transmission 9 can switch asynchronously.

[0027] In the illustrated embodiment, the secondary transmission 10 of the group transmission 2 is designed as a two-stage transmission and is also implemented in the form of an intermediate shaft structure, wherein the two transmission stages K1 and K2 of the secondary transmission 10 form two switchable input constant stages of the main transmission 9. These two transmission stages K1 and K2 have a small transmission ratio difference.

[0028] The idler gear of the first transmission stage K1 is rotatably mounted on the input shaft 6. The idler gear of the second transmission stage K2 is rotatably mounted on the main shaft. The fixed gears of the two transmission stages K1 and K2 of the auxiliary transmission 10 are arranged against relative rotation with the intermediate shafts 21 and 22 of the main transmission 9, which are extended on the input side. The shifting elements 12 and 13 of the auxiliary transmission 10, i.e., the so-called synchronous shifting elements, are combined into a common shifting assembly 14.

[0029] The range gear group 11 of the group transmission 2, located after the main transmission 9, is also designed as a two-stage gear system, but instead of a main transmission, it is designed as a planetary gear transmission 24. The sun gear 25 is connected to the main shaft of the main transmission 9 on the output side in an anti-relative rotational manner. The planet carrier 27 is coupled to the output shaft 8 of the group transmission 2 in an anti-relative rotational manner. The ring gear 26 is connected to a shift assembly 23 with two synchronized shift clutches, through which the range gear group 11 can alternately shift to the low-speed driving stage L by connecting the ring gear 26 to the stationary housing part 7, and to the high-speed driving stage S by connecting the ring gear 26 to the planet carrier 27. The range gear group 11 can shift synchronously.

[0030] Figure 1 A transmission brake 4 acting on the intermediate shaft 21 is also shown. The intermediate shaft 21 can be braked via the transmission brake 4.

[0031] It should be noted that: the group transmission 2 in Figure 1 The embodiments shown are preferred, but optional. The invention can also be used in combination with other group transmissions.

[0032] Therefore, the grouped transmission 2 may consist only of the main gear group 9 and the range gear group 11, or it may consist only of the main gear group 9 and the auxiliary transmission 10. It is also possible that a dog clutch shifting element is used in the area of ​​the auxiliary transmission 10 and / or in the area of ​​the range gear group 11.

[0033] The present invention relates to a method for operating a drive system having a grouped transmission 2 from a state, wherein when the speed of the vehicle is less than a boundary value, a disengagement clutch 5 is disengaged, and for transmission pre-selection, one sub-transmission of the grouped transmission 2 is shifted to neutral or toward neutral, and other sub-transmissions of the grouped transmission 2, or each other sub-transmission, are shifted to a force-locked state or toward a force-locked state, so that the grouped transmission 2 quickly shifts to the force-locked state. Figure 1In the group transmission 2, the sub-transmission that is shifted to neutral for transmission pre-selection is preferably the main transmission 9. For transmission pre-selection, the auxiliary transmission 10 and the range gear group 11 are shifted to a force-locked state or towards a force-locked state, thus engaging the auxiliary transmission and the range gear group, or positioning them in a tooth-to-tooth configuration. From this state, it should be possible to shift the group transmission 2 to the force-locked state, i.e., the sub-transmission that is still in neutral, within a short time. Subsequently, refer to... Figure 2 The method according to the invention is described using a signal flow graph.

[0034] In box 28, it is checked whether the speed of the vehicle has become less than a boundary value. If so, the process branches off from box 28 to box 29, where the disengagement clutch 5 is disengaged and, for gear pre-selection of the group transmission 2, the sub-transmission of that group transmission is shifted to neutral or toward neutral, while the other sub-transmissions, or each additional sub-transmission, are shifted to a force-locked state or toward a force-locked state. In box 30, it is checked whether the corresponding sub-transmission to be shifted to neutral is in neutral and whether the other sub-transmissions, or each additional sub-transmission, are shifting toward a force-locked state. This can be checked using a displacement sensor that cooperates with the shift element.

[0035] If it is confirmed in box 30 that the transmission pre-selection has been completed, then in box 31 the disengagement clutch 5 is at least partially engaged, and in box 32 the drive unit 1 is brought to a predetermined speed, which may correspond, for example, to the idle speed of the drive unit 1 or may be greater than the idle speed of the drive unit 1 by a predetermined offset.

[0036] Then, in box 33, it is checked whether the driver requests a shift to engage the group transmission 2 when the force-locked transmission 2 is required, or whether the driver expects a shift to bring the group transmission 2, which is not yet force-locked, into a force-locked state.

[0037] In this case, check in box 33 whether the vehicle's current speed is less than the second boundary value. If the vehicle's current speed is less than the second boundary value, it is deduced that a gear shift is required, and then the process branches to box 34.

[0038] If it is confirmed in box 33 that the vehicle's speed is greater than the second boundary value, then the process branches off from box 33 to box 35, where the driver's side accelerator pedal operation and / or driver's side brake pedal operation is checked. If the check in box 33 confirms that the vehicle's current speed is greater than the second boundary value and the check in box 35 confirms that the brake pedal is not or is no longer being operated on the driver's side and / or the accelerator pedal is being operated on the driver's side, then the driver is asked to shift gears and the process branches off to box 36.

[0039] In box 36, the target gear of the grouped transmission 2 is determined based on the current driving conditions of the motor vehicle in response to the driver's desired gear shift, and the target speed of the drive unit 1 is determined based on the target gear.

[0040] The current lane gradient and / or current vehicle mass can be taken into account as the current driving conditions of the motor vehicle, and the target gear of the grouped transmission 2 can be determined based on these current driving conditions.

[0041] After knowing the target gear that the driver expects to shift to and the target speed of drive unit 1, check in box 37 whether the transmission pre-selection in box 29 matches the target gear known in box 36.

[0042] If it is confirmed that the pre-selected transmission gear does not match the target gear, the process branches off from box 37 to box 38 and terminates. If it is confirmed that the pre-selected transmission gear matches the target gear that the driver expects to shift into, the process branches off from box 37 to box 39 and continues.

[0043] Check in box 39: if the required driver-expected shift has a target gear that matches the pre-selected gear, is the target speed of the drive unit greater than or less than the current transmission input speed on the input shaft 6 of the group transmission 2?

[0044] If it is confirmed in box 39 that the target speed of drive unit 1 is less than the current transmission input speed, then the branch point from box 39 to box 34.

[0045] If it is confirmed in box 39 that the target speed of drive unit 1 is greater than the current transmission input speed, then the branch point from box 39 to box 40.

[0046] In block 34, in order to perform the corresponding gear shift, the disengagement clutch 5 is disengaged and the sub-transmission of the group transmission 2, which is in neutral and should be shifted to the force-locked state, is synchronized by the transmission brake 4, wherein, after the synchronization, the sub-transmission is shifted to the force-locked state.

[0047] In order to perform the corresponding shift in box 40, the disengagement clutch 5 remains at least partially closed and synchronizes the sub-transmission in neutral by means of the drive unit 1, in order to set a defined target speed at the drive unit 1, wherein, after synchronization, the currently synchronized sub-transmission can be shifted from neutral to a force-locked state by the drive unit 1.

[0048] Using the method according to the present invention, the group transmission 2 can be switched to a force-locked state in a short time from a non-force-locked state (in which the sub-transmissions of the group transmission 2 are in neutral and other sub-transmissions or each other sub-transmissions are switched to a force-locked state), so that driving torque can be transmitted through the group transmission 2 toward the output end 3.

[0049] The present invention also relates to a control device for performing the above-described method, the control device being configured to automatically perform the above-described method.

[0050] Preferably, the control device is an electrical or electronic transmission control device, having both hardware and software components. The hardware components include a data interface for exchanging data with components involved in performing the method according to the invention. The hardware components also include a processor for data processing and a memory for data storage. The software components include program modules implemented in the control device to perform the method according to the invention.

[0051] If the speed of the motor vehicle becomes less than the boundary value, the control device drives the disengagement clutch 5 to disengage. The control device also drives the group transmission to perform transmission pre-selection, such that one of the sub-transmissions of the group transmission 2 is driven to shift to neutral and the other sub-transmissions or each of the other sub-transmissions is driven to shift to the force-locked state.

[0052] Then, the control device drives the disengagement clutch 5 to at least partially close and drives the drive unit 1 to provide a defined speed, wherein the drive unit 1 is driven directly or indirectly by another control device.

[0053] Then, the control equipment checks whether, when the force-locked group transmission requires a shift to start or the driver desires a shift to bring the group transmission 2 into a force-locked state, i.e., engaging a gear in the sub-transmission that was previously in neutral.

[0054] When executing a driver-desired gear shift, the control device checks whether the target speed of the drive unit 1 for the driver-desired gear shift is greater than or less than the current input speed of the group transmission 2.

[0055] If a shift is requested, and if the target speed of drive unit 1 is less than the current input speed of group transmission 2 when a shift is requested by the driver, the control device disengages the disengagement clutch and actuates transmission brake 4 to synchronize the sub-transmission in neutral. After synchronization, the control device actuates the sub-transmission via transmission brake 4 to transition to a force-locked state. If the target speed of drive unit 1 is greater than the current input speed of group transmission 2 when a shift is requested by the driver, drive unit 1 synchronizes the sub-transmission still in neutral, and the control device subsequently actuates the synchronized sub-transmission to transition to a force-locked state.

[0056] Figure Labels

[0057] 1. Drive unit

[0058] 2-group transmission

[0059] 3 Output terminal

[0060] 4. Transmission brakes

[0061] 5. Disengage the clutch

[0062] 6 Input axes

[0063] 7. Shell Section

[0064] 8 Output shafts

[0065] 9. Main Gearbox

[0066] 10 auxiliary transmissions

[0067] 11 Range Blocks

[0068] 12 Synchronous shifting elements

[0069] 13 Synchronous shifting elements

[0070] 14. Gear Shift Assembly

[0071] 15. Shifting elements

[0072] 16. Shift element

[0073] 17. Shift assembly

[0074] 18. Shift element

[0075] 19. Shift element

[0076] 20 Shift assembly

[0077] 21 Intermediate Shaft

[0078] 22 Intermediate Shaft

[0079] 23. Gear Shift Assembly

[0080] 24 Planetary gear transmission device

[0081] 25. Sun Wheel

[0082] 26 Gear Ring

[0083] 27 Planetary Carrier

[0084] 28 frames

[0085] 29 frames

[0086] 30 frames

[0087] 31 frames

[0088] 32 frames

[0089] 33 frames

[0090] 34 frames

[0091] 35 frames

[0092] 36 frames

[0093] 37 frames

[0094] 38 frames

[0095] 39 frames

[0096] 40 frames

Claims

1. A method for operating a drive system of a motor vehicle, in, The drive system has a drive unit (1), a group transmission (2) connected between the drive unit (1) and the output end (3), and a disengagement clutch (5) connected between the drive unit (1) and the group transmission (2), wherein the group transmission (2) has a plurality of sub-transmissions, namely, at least one main transmission (9) and an auxiliary transmission (10) connected before the main transmission (9) and / or a range gear group (11) connected after the main transmission (9). If the speed of the motor vehicle becomes less than a boundary value, the disengagement clutch (5) is disengaged, and for transmission pre-selection, one of the sub-transmissions is shifted to neutral or toward neutral, and the other sub-transmissions or each of the other sub-transmissions is shifted to a force-locked state or toward a force-locked state. Subsequently, at least partially, the disengagement clutch (5) is engaged, and the drive unit (1) reaches a predetermined speed. Then, it is checked whether the required shift is initiated or the driver expects the shift when the group transmission (2) requires force lock-up. If the driver expects a gear shift to be requested, then it is checked whether the target speed of the drive unit (1) is greater than or less than the current input speed of the group transmission (2). If a shift is requested to initiate a gear change, and if the target speed of the drive unit (1) is less than the current input speed of the group transmission (2) when the driver is requested to shift gears, the disengagement clutch (5) is disengaged and the sub-transmission in neutral is synchronized by the transmission brake (4), and after synchronization, the sub-transmission is switched to a force-locked state. If the target speed of the drive unit (1) is greater than the current input speed of the group transmission (2) when the driver is required to shift gears, the drive unit (1) synchronizes the sub-transmission in neutral and then switches the sub-transmission to a force-locked state after synchronization.

2. The method according to claim 1, characterized in that, In order to check whether a start-up shift is required in the case of a grouped transmission (2) requiring force lock-in, it is checked whether the current speed of the vehicle is less than a second boundary value, wherein if the current speed of the vehicle is less than the second boundary value, a start-up shift is required.

3. The method according to claim 2, characterized in that, In order to check whether a driver-expected shift has been requested for the group transmission (2) in the case of a force-locked transmission (2), in addition to checking the speed of the motor vehicle, the operation of the accelerator pedal and / or the operation of the brake pedal on the driver's side are also checked, wherein if the current speed of the motor vehicle is greater than the second boundary value, and furthermore, if the brake pedal is no longer operated on the driver's side and / or the accelerator pedal is operated on the driver's side, then a driver-expected shift is requested.

4. The method according to any one of claims 1 to 3, characterized in that, If the driver expects a gear shift to be required, the target gear of the group transmission (2) is determined based on the current driving conditions of the motor vehicle, and the target speed of the drive unit (1) is determined based on the target gear.

5. The method according to claim 4, characterized in that, The target gear of the grouped transmission (2) is determined based on the current lane slope and / or the current vehicle mass.

6. The method according to claim 4, characterized in that, After determining the target gear, check whether the pre-selected transmission gear matches the target gear. If it is confirmed that the pre-selected gearbox does not match the target gear, the method is terminated. If it is confirmed that the pre-selected gearbox matches the target gear, the method is not terminated.

7. Control equipment for the drive system of a motor vehicle. in, The drive system has a drive unit (1), a group transmission (2) connected between the drive unit (1) and the output end (3), and a disengagement clutch (5) connected between the drive unit (1) and the group transmission (2), wherein the group transmission (2) has a plurality of sub-transmissions, namely at least one main transmission (9) and an auxiliary transmission (10) connected before the main transmission (9) and / or a range gear group (11) connected after the main transmission (9). If the speed of the motor vehicle becomes less than the boundary value, the control device drives the disengagement clutch (5) to disengage and, in order to preselect the transmission, drives one of the sub-transmissions to shift to neutral or towards neutral, and drives the other sub-transmissions or each of the other sub-transmissions to shift to a force-locked state or towards a force-locked state. The control device then drives the disengagement clutch (5) to at least partially close and drives the drive unit (1) to provide a defined speed. The control device then checks whether, in the case of a force-locked gearbox (2), a start-up shift or a shift is requested for the gearbox (2). If the driver expects a gear shift to be requested, the control device checks whether the target speed of the drive unit (1) is greater than or less than the current input speed of the group transmission (2). If a shift is required to initiate, and if the target speed of the drive unit (1) is less than the current input speed of the group transmission (2) when the driver expects a shift to be required, then the control device drives the disengagement clutch (5) to disengage and synchronizes the sub-transmission in neutral by means of the transmission brake (4), and after synchronization, drives the sub-transmission to transition to a force-locked state. If the target speed of the drive unit (1) is greater than the current input speed of the group transmission (2) when the driver expects a gear shift, the control device synchronizes the sub-transmission in neutral through the drive unit (1) and drives the sub-transmission to change to a force-locked state after synchronization.

8. The control device according to claim 7, characterized in that, The control device is configured to perform the method according to any one of claims 1 to 3.

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