The new Audi S Tronic gearbox: Improving driving dynamics
28 March 2008
Mumbai: German car maker, Audi has introduced a new phase in the evolution of transmission systems with the introduction of the new S tronic, a gearbox, which has seven gears that shift at lightning speed without interrupting traction.
The new transmission, which was developed entirely by Audi combines the advantages of a conventional six-speed manual-shift gearbox with the qualities possessed by a modern automatic transmission. The car fitted with the system will be a driving pleasure, at the same time, smooth, dynamic acceleration with no interruption to the power flow.
Audi drivers can operate the S tronic manually or allow changes to take place automatically. The fully automatic mode, in which the computer selects the gear, keeps the D (Drive) and S (Sport) programs available. Manual shifts are made either at the gear lever or at shift paddles behind the steering wheel.
The S tronic is composed of two transmission structures. It integrates two multidisk clutches that control different gears. One of the two clutches engages the odd-numbered, the other the even-numbered gears. This principle enables gear shifts to be made without interrupting the power flow and keeps the shift times extremely short.
While the first clutch is transmitting the power, the second clutch is ready to engage the next gear, which is preselected. When the driver makes the gear shift, the first clutch is released and the second engages, so that the gear shift takes place in a fraction of a second.
A unique feature of the seven-speed S tronic is its two separate oil systems. While the twin clutch, mechatronic module and oil pump are supplied by their own oil circuit with seven liters of automatic transmission fluid (ATF) oil, the wheelsets and the central and front-axle differential are lubricated with about 4.5 liters of hypoid gear oil. This separation allowed the development engineers to position all of the components ideally, without being forced to compromise by using a single lubricant.
Audi will introduce the new S tronic into multiple model lines in series production during the course of this year.