Zf Friedrichshafen Ag

Jonas Knör

Thilo Schmidt

Michael Miller

Anton Fritzer

Andreas Schmidt

Mario Hasel

Christoph Köhler

Valentine Vincent

Jakob Mayer

Philipp Kölbl

Christian Hunger

Fabian Schöniger

Robert Schanuel

A method for operating a drive train () of a vehicle monitoring the actual slip forming at a particular first shift element of a transmission (), comparing the actual slip with a target slip, adapting a characteristic map depending on a deviation between the actual slip and the target slip. The characteristic map is used to determine a shift-element pressure for providing the target slip for a particular first shift element in order to implement a gear ratio change.

Method and control unit for operating a drive train of a vehicle

A method for filling an actuator in a gearbox fills the actuator only when the gearbox is in a passive state by virtue of fluid being introduced into an armature space of the actuator by way of axial movements of an armature rod when the actuator has been fluidically connected to a fluid-filled fluid space of the gearbox.

Filling an armature space of an actuator

A method for operating a friction-locking shift element of a transmission of a motor vehicle includes actuating the friction-locking shift element for engagement according to a pressure versus torque characteristic curve. The pressure versus torque characteristic curve has a first characteristic point (a touch point) and a second characteristic point (a contact point), defines a first characteristic curve range between the touch point and the contact point having a first functional dependence, and defines a second characteristic curve range at or after the contact point having a second functional dependence. Once the touch point is reached, the friction-locking shift element begins to transmit torque mainly due to drag torques. Whereas, once the contact point is reached, the friction-locking shift element begins to transmit torque mainly due to friction between shift-element halves of the friction-locking shift element.

Method for operating a friction-locking shift element of a transmission, and control unit

A vehicle transmission includes a hydraulic circuit and a control unit. The control unit is configured to: obtain () a target pressure specification; convert () the target pressure specification into a target volume flow rate; determine () a valve volume flow rate as a function of the target volume flow rate and as a function of parameters that represent system properties of the hydraulic circuit; determine () a pressure drop at a valve due to flow forces as a function of the valve volume flow rate; determine () a compensated valve output pressure as a function of the valve volume flow rate and the pressure drop; determine () the electric control current as a function of the compensated valve output pressure; and activate a valve with the electric control current.

Method for the open-loop control of an electrically controllable valve in a vehicle transmission

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Erbach, Germany

Jonas Knör