Up to now, manual transmissions have offered one distinct set of benefits and drawbacks, and automatics other quite different ones. This is yet another area of automotive compromise, with distinct trade-offs inherent in either choice or option.
BorgWarner’s DualTronic™ dual clutch, direct shift gearbox is an entirely new concept in automatic transmissions. It has the lighter weight, packaging efficiencies, and fuel economy of a manual transmission. However, in addition, the smooth continuity of its up- and down-shifts would challenge any existing automatic successfully.
In effect, by having two clutches, it splits a gearbox into two three-speed automatics, one with gears 1, 3, and 5 (+ reverse), the other devoted to gears 2, 4, and 6. The innovation, among other features, is the ability to have two gear sets engaged simultaneously. During the shifting process, controlled overlapping of the clutches allows one gear set to be receiving increasing torque, right up to full, while the previously-engaged higher or lower gears are simultaneously having torque withdrawn as the clutch opens, from full down to zero. In this way, torque to the wheels is continuously and seamlessly managed through the gears, up or down.
The result is a drivetrain that provides the efficiency of a manual but the convenience and effortlessness of an automatic. And even automated manuals available to now inevitably display some brief hitch in power delivery, as the clutch opens to allow selection of the new gear ratio. This system, however, has virtually zero discontinuity or interruption of torque being sent to the wheels and applied to the road surface, whether shifting is fully automatic or sport-shift mode. The benefit is smoothness, stability, and uninterrupted torque, while, at the same time, fuel economy and compact light weight resemble those of a pure manual.
The result is brilliant and easily discernible gains in driving performance. The BorgWarner dual clutch DSG feature already contributes very appreciably to equipped Audi TT 3.2 quattros and VW Golf R32s. This innovation is being rolled out across the entire VW Group line-up of vehicles.