Patent ID: 7823710

Claim:
A hydraulic control system ( 1 A) for controlling a hydrodynamic torque converter ( 1 ) and a torque converter lockup clutch ( 2 ) of an automatic transmission, the control system comprising: a supply pressure (p_WD_zu) of the hydrodynamic torque converter ( 1 ), a supply pressure (p_WK zu) of the torque converter lockup clutch ( 2 ), the torque converter lockup clutch ( 2 ) being engaged when the supply pressure (p_WD_zu) of the hydrodynamic torque converter ( 1 ) is smaller than a first predefined pressure level of the supply pressure (p_WK_zu) of the torque converter lockup clutch ( 2 ); a torque converter pressure valve (WDV) for controlling the supply pressure (p_WD_zu) of the torque converter ( 1 ) has a valve slide (WDV_S) which is acted upon by at least a pre-control pressure (p_VS) and a system pressure (p_sys); a torque converter clutch valve (WKV) for controlling the supply pressure (p_WK_zu) of the torque converter lockup clutch ( 2 ) has a valve slide (WKV_S) which is acted upon by at least the pre-control pressure (p_VS) and the system pressure (p_sys), the valve slide (WKV_S) of the torque converter clutch valve (WKV) has an active surface ( 15 ); and the active surface ( 15 ) of the valve slide (WKV_S) of the torque converter clutch valve (WKV) is acted upon, when the torque converter lockup clutch ( 2 ) is disengaged, by a reverse pressure (p_WD_ab) of the torque converter ( 1 ) and when the torque converter lockup clutch ( 2 ) is engaged, by the supply pressure (p_WK_zu) of the torque converter lockup clutch ( 2 ), such that over an entire operational area of the torque converter ( 1 ), one of the supply pressure (p_WD_zu) of the torque converter ( 1 ) and the supply pressure (p_WK_zu) of the torque converter lockup clutch ( 2 ) is greater than a prime predefined pressure level (p_ 0 ).