Doppelkupplung

Dual-mass Flywheel

The engine torque is routed into the clutches via a dual-mass flywheel.

Doppelkupplung

The wet dual clutch or Doppelkupplung is a central module of the PDK transmission. With its wide range of technical features, it meets the functional requirements of the transmission control system, thereby shaping the special character of this transmission concept.

Very fast response times, low inertia and good, comfortable friction values, combined with good economic viability allow both very sporty driving with highly dynamic gear changing as well as comfortable cruising. For safety reasons, the clutches are opened when they are depressurized and inactive.

The radial arrangement of the disc packs provides the best combination from the point of view of performance and space.







Careful selection of pad type, pad dimensions and usage as well as uniform distribution of thermal load and oil flow in the disc pack, along with the corresponding oil types, are prerequisites for comfort and performance over the service life.

Low drag torques even at low temperatures as well as good resistance at high speeds guarantee comfort and excellent sportiness, but are also important safety requirements.

Function

The Doppelkupplung is positioned directly on the transmission input. It transfers the engine torque from the dual-mass flywheel via the profile of its input shaft and passes it through the housing cover of the dry chamber into the wet chamber and on to the clutch primary.







The disc packs are arranged radially over each other. The clutch sends the torque either to the odd gears 1st, 3rd, 5th and 7th and to reverse gear via the outer disc pack, or to the transmission with 2nd, 4th and 6th gear via the inner disc pack, depending on which of the two is activated by the control pressure of the hydraulic transmission control system.

The torque is routed into the two transmissions via the profiles of the transmission input shafts.

Special hydraulic oil is used for actuating the Doppelkupplung hydraulically and for cooling the clutch. This oil is also used for shifting gears. PDK has a separate oil circuit for lubricating the gear wheel set and for cooling. This oil must not be mixed with hydraulic oil.

Both clutches can be actuated and operated with slip regulation independently of each other.

Both clutches display slight centrifugal force overcompensation. The Doppelkupplung is not fully slip-regulated in any operating state, which means that the vehicle must be held with the brake when in gear to prevent it from rolling away.

Clutch cooling







The clutches are cooled with a separate oil flow to prevent them from overheating. Clutch cooling and clutch control are activated at the same time. The cooling oil flow is regulated by a control valve on the hydraulic control unit.