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CN-117098939-B - Method and control device for operating a drive train

CN117098939BCN 117098939 BCN117098939 BCN 117098939BCN-117098939-B

Abstract

A method for operating a drive train of a motor vehicle, comprising a drive train (1), a group transmission (2) with subtransmissions, and a disconnect clutch (5) connected between the drive train and the group transmission, wherein if a speed change is to be less than a limit value, the disconnect clutch (5) is disengaged and one of the subtransmissions is shifted to a neutral position for transmission preselection, and the other subtransmissions or each further subtransmission is shifted to a force-locking state, wherein the disconnect clutch (5) is subsequently at least partially closed and the drive train (1) is brought to a defined rotational speed, wherein a subsequent check is made as to whether a start-up shift or a driver-desired shift is present in the group transmission (2) when a force-locking group transmission (2) is required, wherein if a driver-desired shift is present, a target rotational speed of the drive train (1) is greater than or less than a current input rotational speed of the group transmission, wherein if a start-up shift is present and if a target rotational speed of the driver-desired shift is less than a current input rotational speed of the group transmission, the disconnect clutch (5) is disengaged and the drive train (1) is brought to a force-locking state by the subtransmission (4) when the driver-desired shift is present and the driver-desired shift is present when the driver-desired shift is in the current input speed of the group transmission (2) is greater than the input speed.

Inventors

  • MARIO STEINBORN
  • Mike Witner
  • Te Yashilvte
  • Fred Norenberg
  • Mertin Fayfel

Assignees

  • 采埃孚股份公司

Dates

Publication Date
20260512
Application Date
20220621
Priority Date
20210624

Claims (8)

  1. 1. A method for operating a drive train of a motor vehicle, Wherein the drive train has a drive train (1), a group transmission (2) connected between the drive train (1) and the output (3), and a separating clutch (5) connected between the drive train (1) and the group transmission (2), wherein the group transmission (2) has a plurality of partial transmissions, namely at least one main transmission (9) and a partial transmission (10) connected upstream of the main transmission (9) and/or a range group (11) connected downstream of the main transmission (9), Wherein if the speed of the motor vehicle becomes less than a limit value, the separating clutch (5) is disengaged and one of the subtransmissions is shifted into or in the direction of neutral for transmission preselection and the or each further subtransmission is shifted into or in the direction of force-locking, Wherein the disconnect clutch (5) is then at least partially closed and the drive train (1) is brought to a defined rotational speed, Wherein it is then checked whether a start shift or a driver desired shift is required for the group transmission (2) when a force-locking group transmission (2) is required, Wherein if a driver desires a gear change to be requested, it is checked whether the target rotational speed of the drive train (1) is greater or less than the current input rotational speed of the group transmission (2), Wherein if a start shift is required and if the target rotational speed of the drive train (1) is less than the current input rotational speed of the group transmission (2) in the event of a request for a driver-desired shift, the separating clutch (5) is disengaged and the transmission brake (4) synchronizes the subtransmission in neutral and, after the synchronization, the subtransmission is brought into a force-locking state, If the target rotational speed of the drive train (1) is greater than the current input rotational speed of the group transmission (2) when a driver is required to shift gears, the transmission in neutral is synchronized by the drive train (1) and, after synchronization, the transmission is shifted into a force-locking state.
  2. 2. The method of claim 1, wherein the step of determining the position of the substrate comprises, In order to check whether a start shift is required in the case of a force-locking group transmission (2), it is checked whether the current speed of the motor vehicle is less than a second limit value, wherein if the current speed of the motor vehicle is less than the second limit value, a start shift is required.
  3. 3. The method of claim 2, wherein the step of determining the position of the substrate comprises, In order to check whether a driver-desired shift is required for the group transmission (2) if a force-locking group transmission (2) is required, a driver-side accelerator pedal actuation and/or a driver-side brake pedal actuation is also checked in addition to the speed of the motor vehicle, wherein if the current speed of the motor vehicle is greater than the second limit value, and furthermore, if the brake pedal is no longer actuated on the driver side and/or the accelerator pedal is actuated on the driver side, a driver-desired shift is required.
  4. 4. A method according to any one of claim 1 to 3, wherein, If a driver desires a gear change to be requested, a target gear of the group transmission (2) is known depending on the current driving conditions of the motor vehicle, and a target rotational speed of the drive unit (1) is known depending on the target gear.
  5. 5. The method of claim 4, wherein the step of determining the position of the first electrode is performed, The target gear of the group transmission (2) is determined as a function of the current lane gradient and/or as a function of the current vehicle mass.
  6. 6. The method of claim 4, wherein the step of determining the position of the first electrode is performed, After learning the target gear, checking whether the transmission preselect matches the target gear, Wherein if it is confirmed that the transmission preselection does not match the target gear, the method is terminated, Wherein the method is not terminated if it is confirmed that the transmission preselect matches the target gear.
  7. 7. Control device for operating a drive train of a motor vehicle, Wherein the drive train has a drive train (1), a group transmission (2) connected between the drive train (1) and the output (3), and a separating clutch (5) connected between the drive train (1) and the group transmission (2), wherein the group transmission (2) has a plurality of partial transmissions, namely at least one main transmission (9), and a partial transmission (10) connected upstream of the main transmission (9) and/or a range group (11) connected downstream of the main transmission (9), Wherein if the speed of the motor vehicle becomes less than a boundary value, the control device drives the disconnect clutch (5) off and drives one of the subtransmissions for transmission preselection to shift into neutral or in the direction of neutral and drives the or each further subtransmission to shift into or in the direction of force-locking, Wherein the control device then drives the disconnect clutch (5) at least partially closed and drives the drive train (1) to provide a defined rotational speed, Wherein the control device then checks whether a start shift or a driver-desired shift is required for the group transmission (2) if a force-locking group transmission (2) is required, Wherein the control device checks if the driver desires a gear change to be requested, if the target rotational speed of the drive train (1) is greater or less than the current input rotational speed of the group transmission (2), Wherein if a start shift is required and if the target rotational speed of the drive train (1) is less than the current input rotational speed of the group transmission (2) in the event that a driver desires a shift to be required, the control device actuates the disconnect clutch (5) to open and synchronizes a subtransmission in neutral via a transmission brake (4) and actuates the subtransmission after synchronization to shift to a force-locking state, Wherein if the target rotational speed of the drive unit (1) is greater than the current input rotational speed of the group transmission (2) when a driver desires a gear change to be requested, the control device synchronizes the subtransmission in neutral gear by the drive unit (1) and drives the subtransmission after the synchronization to shift to a force-locking state.
  8. 8. A control device according to claim 7, characterized in that the control device is set up for performing the method according to any one of claims 1 to 3.

Description

Method and control device for operating a drive train Technical Field The invention relates to a method for operating a drive train of a motor vehicle, wherein the drive train has a drive train, a group transmission connected between the drive train and an output, and a disconnect clutch connected between the drive train and the group transmission, and wherein the group transmission has a plurality of subtransmissions, namely at least one main transmission and a subtransmission connected in drive front of the main transmission and/or a range group connected in drive behind the main transmission. The invention also relates to a control device for operating such a drive train. Background Motor vehicle drive trains are known from the prior art, which have group transmissions as transmissions. The group transmission has a main transmission, a range group connected downstream of the main transmission in drive technology and/or a range group connected downstream of the main transmission in drive technology. The main transmission is also called a main gear set. DE 10 2007 007 257 A1 discloses the use of an electric motor as a synchronizing mechanism during gear shifting in a group transmission. If the motor vehicle with the group transmission is decelerating, i.e. slow, the disconnect clutch is disconnected below a certain threshold value of the speed of the motor vehicle and the drive train is thus decoupled from the transmission. If the group transmission is to be shifted from this state to the force-locking state, that is to say either in the case of a start-up shift being carried out in the group transmission or in the case of a driver-desired shift being carried out in the group transmission, a long synchronization time can occur and thus the shifting of the group transmission to the force-locking state can take a long time, since the input shaft of the group transmission is rotationally decoupled when the separating clutch is disengaged and the group transmission is not force-locked. Long synchronization times of the packet transmission can lead to reduced comfort. There is a need to synchronize and thus transition the group transmission from the non-force-locking state to the force-locking state faster. DE 10 2007 012 875 A1 discloses a method for operating a drive train in which, if a motor vehicle rolls with a starting clutch open, a gear matching the current speed of the motor vehicle is shifted out of the transmission in order to provide a gear matching the speed of the motor vehicle present when the starting clutch is subsequently closed. DE 10 2007 010 295 A1 discloses a further method for operating a drive train of a motor vehicle, i.e. for executing a so-called freewheeling shift during freewheeling of the motor vehicle. Disclosure of Invention The object on which the invention is based is to provide a novel method for operating a drive train of a motor vehicle and a control device for carrying out the method. This object is achieved by the method according to the invention for operating a drive train. If the speed of the motor vehicle becomes less than the limit value, the separating clutch is disengaged and one of the subtransmissions is shifted into or in the direction of neutral for transmission preselection and the or each further subtransmission is shifted into or in the direction of force-locking. Subsequently, the disconnect clutch is at least partially closed and the drive train is brought to a defined rotational speed. Subsequently, it is checked whether a start shift or a driver desired shift is required for the group transmission in the case of a force-locking group transmission. If the driver desires a shift to be requested, it is checked whether the target rotational speed of the drive train is greater or less than the current input rotational speed of the group transmission. If a start shift is required and if the target rotational speed of the drive assembly is less than the current input rotational speed of the group transmission in the event that a driver desires a shift to be required, the separating clutch is disengaged and the subtransmission in neutral is synchronized by the transmission brake and is shifted into a force-locking state after synchronization. If the target rotational speed of the drive unit is greater than the current input rotational speed of the group transmission when the driver desires a shift to be requested, the subtransmission in neutral is synchronized by the drive unit and is shifted into a force-locking state after the synchronization. With the method according to the invention it is proposed that when the speed of the motor vehicle is below a limit value, if the separating clutch is opened and if one of the sub-transmissions of the group transmission is shifted into neutral or in the direction of neutral, while the or each further sub-transmission of the group transmission is shifted into or in the direction of force-locking, the separating clutch is a