Zf Friedrichshafen Ag

Jakob Mayer

Mario Hasel

Thilo Schmidt

Anton Fritzer

Andreas Schmidt

Christoph Köhler

Jonas Knör

Valentine Vincent

Anshuman Deshpande

Michael Miller

Christian Hunger

Fabian Schöniger

A method for operating a hydraulic system () of a transmission () of a motor vehicle i includes ascertaining an actual volumetric flow of oil that is deliverable into a primary hydraulic circuit () by at least one hydraulic pump (), ascertaining a target volumetric flow of oil that is required by the primary hydraulic circuit (), and ascertaining an excess volumetric flow of oil depending on the actual volumetric flow of oil and the target volumetric flow of oil. The excess volumetric flow of oil is distributed to shift elements of the transmission () to be actuated, depending on the hydraulic capacity of these shift elements, and is taken into account when limiting the pressure actuation of the shift elements of the transmission () to be actuated.

Method and control unit for operating a hydraulic system of a transmission of a motor vehicle

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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Kressbronn, Germany

Jakob Mayer