Audi has a long tradition in the development of innovative transmission technologies and their use in production vehicles and the company's latest variation on the theme is the Direct Shift Gearbox or DSG.
If this term sounds familiar, it's because BMW offers a similar transmission which it calls Sequential Manual Gearbox (SMG) as options on the Z4 and M3 .
The DSG is a six-speed manual transmission that can offer both manual and automatic transmission. It uses all the same ingredients as a manual transmission but with an extra clutch.
Both clutches are electrohydraulically controlled and this allows two gears to be selected at the same time to minimize interruption in power delivery during shifts. As one clutch opens, the other closes.
There's even some smarts in there to automatically preselect the most likely gear you'll be looking for next. Expert opinion suggests the resultant vehicle drives exceptionally.
The first Audi to use the new technology goes on show at the forthcoming 2004 Australian International Motor Show (AIMS) - the TT 3.2 quattro gets the DSG, six cylinders for the first time and Audi's quattro drive complete's the digitally controlled drive train by routing the power to each wheel via an electronically controlled centre differential.
Audi's tradition in transmission innovation was first demonstrated in 1994 with the tiptronic in 1994 and ingenious design of the continuously variable multitronic transmission in 1999.
The company's use of twin clutches goes way beyond this new gearbox though as the twin-clutch transmission has its roots in motor racing. Audi used it in the legendary Audi Sport quattro back in 1985, with Walter Ršhrl behind the wheel. He completed successful test drives in the Audi Sport quattro S1, a rally vehicle whose victories included the legendary Pikes Peak Hill Climb.
The revolutionary Direct-Shift Gearbox combines the advantages of a conventional 6-speed manual gearbox with the qualities of a modern automatic transmission. The driver thus benefits from enormous agility and driving enjoyment with acceleration that is as harmonious as it is dynamic, without any interruption in the power flow. This is combined with good economy thanks to low fuel consumption, and convenient operation.
The basis for this new development is a three-shaft 6-speed manual gearbox which offers considerable variability in the selection of the transmission ratio. Thanks to the use of a twin multi-plate clutch with ingenious electro-hydraulic control, two gears can be engaged at the same time.
During dynamic operation of the car, one gear is engaged. When the next gearshift point is approached, the appropriate gear is preselected, but its clutch kept disengaged. The gearshift process opens the clutch of the activated gear and closes the other clutch at the same time with a certain overlap. The gear change takes place under load, with the result that a permanent flow of power is maintained.
The control logic integrated into the transmission casing maintains optimum gearshift strategies that perform lightning-fast gearshifts that are nevertheless smooth and almost jolt-free. The driver can directly influence the gear selected and the gearshift timing at will, by means of the gear lever in the manual gate or, in the style of a racing driver, using the standard-fit shift paddles on the steering wheel.
In the automatic mode, the driver can shift to the ultra-sporty S program in which upshifts are significantly retarded, downshifts advanced and the shifting process accelerated. A remote one-touch function accessed via the shift paddles on the steering wheel in addition temporarily calls up the manual mode, even in automatic modes D and S.
High overall efficiency is thus combined with superlative road performance and ease of operation to produce an exceptional drive concept.