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1. (WO2018024730) HYDRAULIC SYSTEM FOR AN AUTOMATIC TRANSMISSION OF A MOTOR VEHICLE

Pub. No.:    WO/2018/024730    International Application No.:    PCT/EP2017/069447
Publication Date: Fri Feb 09 00:59:59 CET 2018 International Filing Date: Wed Aug 02 01:59:59 CEST 2017
IPC: F16H 61/688
F16H 61/12
F15B 19/00
Applicants: AUDI AG
Inventors: WEINHARDT, Mathias
Title: HYDRAULIC SYSTEM FOR AN AUTOMATIC TRANSMISSION OF A MOTOR VEHICLE
Abstract:
The invention relates to a hydraulic system for an automatic transmission of a motor vehicle, with which hydraulic cylinders (22, 23) of at least one clutch (K1, K2) and of gear selectors (G1 to G4) can be actuated, which hydraulic system has a pressure accumulator (25) for providing an accumulator pressure (ps) in the hydraulic system, wherein a clutch valve (35) that can be controlled by the control unit (39) is arranged in a clutch path (30, 31) leading from the pressure accumulator (25) to the clutch hydraulic cylinder (23), with which clutch valve a hydraulic pressure at the clutch hydraulic cylinder (23) can be adjusted, and a gear selector valve (35) that can be controlled by an electronic control unit (39) is arranged in at least one gear selector path (32) leading from the pressure accumulator (25) to the gear selector hydraulic cylinder (22), with which gear selector valve the hydraulic pressure at the gear selector hydraulic cylinder (22) can be adjusted, wherein a pressure sensor (34) is assigned to said control unit (39), with which the hydraulic pressure at the clutch hydraulic cylinder (23) can be detected, and comprising a charging hydraulic pump (53) which conveys hydraulic fluid into the hydraulic system in a charging process, in order to increase the actual accumulator pressure (pS). According to the invention, the control unit (39) has a diagnosis module (79) with which a diagnosis of the gear selector path can be carried out, wherein the diagnosis module (79) checks a leakage behaviour in the gear selector path (32) using the pressure sensor (34) arranged in the clutch path (30, 31).