Method and control device for operating a drive train

By partially closing a friction-locked brake during neutral shifts, the method addresses the jolt issue in engaging positive-locking gears, achieving smooth transitions and enhanced comfort.

DE102018215455B4Active Publication Date: 2026-05-28ZF FRIEDRICHSHAFEN AG
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Patent Information

Application Number
DE102018215455
Authority / Receiving Office
DE · DE
Patent Type
Patents
Current Assignee / Owner
Filing Date
2018-09-12
Publication Date
2026-05-28
Estimated Expiration
2038-09-12

AI Technical Summary

Technical Problem

Engaging a positive-locking gear after shifting a transmission from neutral with the engine running results in a noticeable jolt in the drivetrain, leading to an uncomfortable driving experience.

Method used

At least partially close a friction-locked switching element, designed as a brake, during or immediately after shifting into neutral to reduce rotational speeds in the gear set of the transmission.

Benefits of technology

Enables smooth engagement of a positive-locking gear without jolts, ensuring a comfortable driving experience by reducing rotational speeds in the gear set.

✦ Generated by Eureka AI based on patent content.

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Abstract

Method for operating a drivetrain of a motor vehicle, wherein the drive train comprises a drive unit (15), a transmission (1) with several switching elements (A, B, C, D, E, F) and an output (16), wherein in each engaged, friction-fit gear of the transmission (1) a first number of switching elements of the transmission (1) are closed and a second number of switching elements of the transmission (1) are open, wherein, when a standstill decoupling of the running drive unit (15) is carried out starting from a friction-locked gear, a switching element of the transmission (1) is opened, so that in the standstill decoupling, compared to the respective friction-locked gear of the transmission (1), one less switching element is closed, wherein, starting from the stationary decoupling of the drive unit (15), when the transmission is moved into neutral, a further switching element of the transmission (1) is opened, so that in neutral, compared to the friction-locked gear of the transmission (1), two fewer switching elements are closed, characterized by the fact that with or immediately after the transmission is moved into neutral, a friction-locked switching element of the transmission (1) designed as a brake is at least partially closed in order to reduce rotational speeds in the gear set of the transmission (1).
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Citation Information

Patent Citations

  • Method for controlling an automated powershift transmission

    DE102008043561A1

  • Method for controlling a lock up clutch of a hydrodynamic converter

    EP2280195A1