Clutch operation

Operation of the dual clutch is not performed by a mechanical or hydraulic release device (central clutch release bearing, clutch release fork) as on "conventional" manual transaxles, but takes place on an entirely electrohydraulic basis. In order to transfer the drive torque of the engine to the internal or hollow shaft and then on to the respective sub-transaxle, one of the clutch packs first has to be frictionally connected via the application of hydraulic pressure.

The hydraulic pressure is controlled by the TCM via two control valves:

• K1 clutch regulation valve
• K2 clutch regulation valve

Depending on the gear being engaged, the hydraulic flow passes via a shift valve connected in series and on to the clutch hub and then to the corresponding pressure chambers of the clutch packs via a rotary connection. Furthermore, part of the pump flow is used to reduce the contact pressure of the clutch plates (dynamic pressure buildup, due to centrifugal forces at high rpms) and for clutch cooling.