Abstract
In the last years Dual Clutch Transmissions (DCT) are constantly situated in the focus of transmissions developers. Comfort aspects (non-interruption of torque) and potential fuel savings are making this kind of transmission a viable alternative to the standard manual transmission also in Europe. Ricardo has designed and developed a DCT transaxle, suitable for the Daimler Chrysler "ME Four - Twelve" prototype vehicle in 12 months (7 months to hardware) and also tested cost reduction technologies in a dual clutch transaxle. The transmission itself is a seven-speed dual clutch automated manual, electronically controlled for torque-interrupt-free shifts with shift times around 200msec. The engine used in this application is a Mercedes-Benz-AMG 6.0 litre V12 with four turbochargers and maximum power 850 HP at 5750 rpm.
The paper shows that a right first time approach was essential in the mechanical design of the transmission. Cost effective and predictive analysis techniques were employed to allow the well-balanced experienced design team to achieve the aggressive goals.
The paper discusses the followings issues:
- brief presentation of major sub-systems
- analysis of design in terms of gears, bearings, shafts and oil compatibility. It will be shown that conflicting requirements from the oils for clutch and the crown wheel and pinion gears lead to the requirement for a two oil system: a EP oil for gears and the gear actuation system and a ATF style oil for the clutch and hydraulics.
- analysis of the gear actuation system and control system
Keywords:DCT, clutch, control, shift, transmission