Zf Friedrichshafen Ag

Anshuman Deshpande

Mario Hasel

Alexander Haberstock

Clemens Moser

Jakob Mayer

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.

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Friedrichshafen, Germany

Anshuman Deshpande