Method for operating a vehicle drive train with a drive motor, an output and a transmission which is arranged between the drive motor and the output

US10539227B2 · kind B2 · utility

Assignee

• ZF FRIEDRICHSHAFEN AG · DE

Inventors

• Peter Schiele · Kreßbronn, DE
• Johannes Brockmann · Gettorf, DE

Key dates

• Filing date: May 18, 2017
• Grant date: Jan 21, 2020
• Expiry date: Feb 12, 2038

Classification

• Technology area (CPC F): Mechanical Engineering; Lighting; Heating
• CPC primary: F16H2312/14
• WIPO field: Mechanical elements
• WIPO sector: Mechanical engineering

Abstract

A method for operating a vehicle drivetrain (1) includes proceeding, in the presence of the demand for activation of the engine start-stop function of the vehicle drivetrain (1) and a simultaneously shut-down drive machine (2), from an operating state of the vehicle drivetrain (1) during which a sailing operating function of the vehicle drivetrain (1) is active, during which the drive machine (2) is decoupled from the drive output (3), during which the positively engaging shift element (F) is open and during which a rotational speed (n_ab) of the drive output (3) is higher than a defined rotational speed at which a rotational speed difference between shift element halves of the positively engaging shift element (F) lies within a rotational speed range within which the positively engaging shift element (F) is transferrable into the closed operating state, and actuating the positively engaging shift element (F) in a closing direction no later than when the defined rotational speed is reached.