Abstract: The invention relates to a hydraulic control device for an automatic dual-clutch transmission which has a first clutch and a second clutch, having a control valve unit which predefines at least one hydraulic parameter such as pressure and/or one volume flow. Regulating this parameter engages or disengage the clutches. An additional separating valve can is provided assuming a normal position when the second control signal is applied, so that at least one of the clutches can be operated by means of the control valve unit. The purpose is to provide enhanced operational safety against misoperation while at the same time secure availability of the clutches.

Abstract: The invention relates to a switching-valve arrangement for a shifting system of an automatic transmission having a first actuator for engaging and releasing gears, at least a second actuator for engaging and releasing gears, a first activatable switching valve, a second activatable switching valve, a first signal element, and a second signal element. By means of the signal elements and switching valves the first and second actuators can be pressurized. In case of failure of one of the signal elements one of the actuators can always be pressurized and even in case of erroneous operation of the first and second signal elements only one of the actuators can be pressurized at the same time.

Abstract: A hydraulic system for providing pressure and volume flows in a double-clutch transmission. A first clutch and a second clutch are preceded by at least one changeover valve which, in a first state, guides lubricating flow to the first clutch and cooling flow to the second clutch, and, in a second state, guides lubricating flow to the second clutch and cooling flow to the first clutch. The cooling flow is preferably variable.