Zf Friedrichshafen Ag

Mario Hasel

Anshuman Deshpande

Alexander Haberstock

Jakob Mayer

Clemens Moser

Thilo Schmidt

Anton Fritzer

Andreas Schmidt

Christoph Köhler

Jonas Knör

Valentine Vincent

Michael Miller

Christian Hunger

Fabian Schöniger

A method for operating a motor vehicle having a transmission including a hydraulic system with a dual-circuit pump includes driving the dual-circuit pump by both an internal combustion engine and an electric machine via a superposition gear unit that superimposes a rotational speed of the internal combustion engine and a rotational speed of the electric machine. The method further includes determining whether a subset is less than a subset threshold value when a target value of a required primary flow increases in a dual-circuit operating state to a value higher than a current primary flow actual value, with the subset being a difference between the target value and the current primary flow actual value. Additionally, the method includes increasing the second rotational speed of the electric machine when the subset is less than the subset threshold value.

Method and control device for operating a transmission

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 method for the open-loop control of a pump system () includes accessing a hydraulic calculation model by an electronic control unit, which includes, for various operating states of a transmission, information regarding oil supplies of two pumps (P, S) of the pump system () and information regarding oil demands of the transmission. The method also include ascertaining a certain oil supply ({dot over (V)}), which the two pumps (P, S) provide in a certain operating state of the transmission according to the hydraulic calculation model. In addition, the method includes ascertaining a certain oil demand ({dot over (V)}), which the hydraulic system () requests of the two pumps (P, S) in the certain operating state of the transmission according to the hydraulic calculation model.

Method for the open-loop control of a pump system

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

An oil supply system for a vehicle transmission includes a pump drivable by two drive sources, and a hydraulic control unit including multiple control valves for distributing oil to consumers of the oil supply system. The drive power of the two drive sources are combined by a planetary gear set having an element connected to a pump drive shaft of the pump. A method for supplying the consumers of the oil supply system includes determining an overall oil flow requirement in the oil supply system and an oil flow requirement of consumers in an oil supply circuit of the transmission. The method further includes calculating a drive parameter for at least one of the two drive sources based at least in part on the oil flow requirements. Additionally, the method includes outputting the drive parameter as a specified value for controlling the at least one of the two drive sources.

Method for supplying consumers of an oil supply system for a vehicle transmission with oil

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Wangen, Germany

Mario Hasel