Abstract: In a valve system for a hydraulically controlled starting friction clutch, a clutch pressure control valve that controls the clutch pressure during the starting phase of the clutch engagement as a function of the torque requirement of the operator, and a valve that overrides the clutch pressure control valve as a function of the output speed wherein a clutch pressure control valve 17 has a valve arrangement that acts as a slippage time limiter, the latter comprising a startup valve 13, an accumulator 14 and an on-off valve 15. After a specific time affected by the selection of the throttle orifices 28a and 28b and the piston rod diameter 27, higher clutch pressure pk (D, L, R) is fed to the clutch pressure control valve.

Abstract: A valve system for a hydraulically controlled starting friction clutch for motor vehicles, a clutch pressure control valve that controls the clutch pressure as a function of the torque demand of the driver, a valve arrangement that modulates a pressure dependent upon the engine speed and that delivers it to the clutch pressure control valve, a shuttle valve 11, a throttle orifice 12 and an accumulator 13 associated with the clutch pressure control valve 1. The shuttle valve 11 comprises a valve member 15 disposed in a valve bore 14 with three control lands 16, 17 and 18 and a spring 19 that acts upon one end of the valve member 15. A pressure signal Ppitot dependent upon the speed is applied by way of lines 21 and 22 between the first control land 16 and the second control land 17 and between the second control land 17 and the third control land 18 and is supplied by way of outlets 23 and 24 and a line 10 to the clutch pressure control valve 1. A pressure signal P.sub.