US 12,379,025 B2
Method and control unit for operating a hydraulic system of a transmission of a motor vehicle
Mario Hasel, Wangen (DE); Jakob Mayer, Kressbronn (DE); and Anshuman Deshpande, Friedrichshafen (DE)
Assigned to ZF Friedrichshafen AG, Friedrichshafen (DE)
Filed by ZF Friedrichshafen AG, Friedrichshafen (DE)
Filed on Jun. 27, 2023, as Appl. No. 18/342,040.
Claims priority of application No. 10 2022 206 494.1 (DE), filed on Jun. 28, 2022.
Prior Publication US 2023/0417319 A1, Dec. 28, 2023
Int. Cl. F16H 61/00 (2006.01)
CPC F16H 61/0021 (2013.01) [F16H 2061/0037 (2013.01)] 9 Claims
OG exemplary drawing
 
1. A method for operating a hydraulic system (1) of a transmission (2) of a motor vehicle, the hydraulic system (1) including a primary hydraulic circuit (10) for pressure actuation of shift elements of the transmission (2), a secondary hydraulic circuit (11) for cooling and/or lubricating assemblies of the transmission (2), and at least one hydraulic pump (3) that delivers a volumetric flow of oil into the primary hydraulic circuit (10) and into the secondary hydraulic circuit (11), the method comprising:
ascertaining an actual volumetric flow of oil that is deliverable into the primary hydraulic circuit (10) by the at least one hydraulic pump (3);
ascertaining a target volumetric flow of oil that is required by the primary hydraulic circuit (10);
ascertaining an excess volumetric flow of oil depending on the actual volumetric flow of oil and the target volumetric flow of oil; and
distributing the excess volumetric flow of oil to the shift elements of the transmission (2) to be actuated, depending on hydraulic capacity of the shift elements of the transmission (2) to be actuated, and limiting pressure actuation of the shift elements of the transmission (2) to be actuated based at least in part on the excess volumetric flow of oil.