Patent Number: 7,823,710

Title: Hydraulic control system for a hydrodynamic torque converter comprising a controlled torque converter lockup clutch

Abstract: Description of a hydraulic control system (1A) for a hydrodynamic torque converter (1) with a controlled torque converter lockup clutch (2) of an automatic transmission for controlling a supply pressure (p_WD_zu) of the torque converter (2) and a supply pressure (p_WK_zu) of the torque converter lockup clutch (2). The torque converter lockup clutch (2) is engaged when the supply pressure (p_WD_zu) of the torque converter (1) is lower than a predefined pressure level of the supply pressure (p_WK_zu) of the torque converter lockup clutch. A converter pressure valve (WDV) is provided for controlling the supply pressure (p_WD_zu) of the torque converter (1), and a converter coupling valve (WKV) for controlling the supply pressure (p_WK_zu) of the torque converter lockup clutch, where their valve slides (WDV_S, WKV_S) can be acted upon by at least one pre-control pressure (p_VS) and one system pressure (p_sys). When the torque converter lockup clutch (2) is disengaged, the valve slide (WKV_S) of the converter coupling valve (WKV) is acted upon in such a way on an active surface (15) by the reverse pressure (p_WD_ab) of the torque converter (1), and when the torque converter lockup clutch (2) is engaged, is acted upon in such a way on the active surface (15) by the reverse pressure (p_WK_zu) of the torque converter lockup clutch (2), that at least either the supply pressure (p_WD_zu) of the torque converter (1) or the supply pressure (p_WK_zu) of the torque converter lockup clutch (2) is higher than a predefined pressure level (p.sub.--0) over the entire operational area of the torque converter (1).

Inventors: Gierer; Georg (Kressbronn, DE), Schmidt; Thilo (Meckenbeuren, DE), Rolser; Tobias (Berg, DE)

Assignee: ZF Friedrichshafen AG

International Classification: F16H 61/14 (20060101)

Expiration Date: 2019-11-02 0:00:00