Ease of an automatic with the responsiveness of a manual
Increasing your driving pleasure
Our acclaimed DSG dual-clutch gearbox has two clutches with electronically controlled
gear selection. DSG gives you:
• Fast, smooth gear changes
• Lively handling with unbroken acceleration
• Safer driving with the power to get you out of tricky situations
• Improved fuel economy, even compared to a manual gearbox, for many of our new
7-speed DSG dual-clutch gear boxes
How does it work?
DSG is a groundbreaking 'two-in-one' concept. Available in 6-speed and 7-speed versions,
it's totally unlike a conventional automatic transmission. Twin electronically controlled
shafts manage gear selection, always anticipating your next shift.
Split-second changes
When you turn the engine on and select Drive mode, one shaft selects first gear
while the second shaft puts the next gear on 'standby'. As the gearbox changes to
second, the second shaft is engaged and the original shaft reaches third. As you
shift upwards the sequence continues in a series of seamless moves. Because power
is simply switched from one shaft to another, not only are gearshifts silky smooth,
but they are also very fast: each change takes less than four-hundredths of a second.
The DSG dual-clutch gearbox gives you a choice of two driving programmes: normal
and sport. In sport mode, the DSG leaves it longer to shift up the gears.
And if you want to take over, you can control the DSG manually. Nudge the Tiptronic
gearlever forwards or backwards to change gear, or use the paddle shifts mounted
on the steering wheel*: left for down, right for up.
Both DSG dual-clutch gearboxes are application-specific. The 6-speed is paired with
high torque engines (up to 350 Nm) while the 7-speed variant is more effective in
combination with smaller engines and torque outputs of up to 250 Nm.
The technology
Two independent gearbox units make up the DSG. With dual-clutch technology - two
clutches in a common housing - both gearboxes are connected under load to the engine
in turn, depending on the current gear, via two drive shafts. Clutch 1 serves the
first gearbox unit with 1st, 3rd, 5th 7th and reverse gear and clutch 2 the second
gearbox unit with 2nd, 4th and 6th gear. An output shaft that applies the torque
to the driven wheels via the differential gear is assigned to each gearbox unit.
Thanks to the dual-clutch design the DSG is more efficient than conventional automatic
transmission. This efficiency, together with its low weight and intelligent control,
means that DSG can achieve the same, and in some instances better, fuel consumption,
than a manual gearbox or even lower, depending on the style of driving.
Mechatronics - electronics and mechanics in one unit
Clutches and gearbox units are operated hydraulically by the gearbox mechatronics
(a combination of mechanics and electronics) housed in the DSG. The electronic transmission
control unit, sensors and hydraulic control unit form one compact unit.
The control unit does the thinking for you, using information such as engine speed,
road speed, accelerator position and driving mode to select the optimum gear and
to determine the ideal shift point. The hydraulic control unit then implements the
shift commands in a sequence of precisely co-ordinated actions.
Split-second gear changes
When one gear is engaged, another gear is always preselected. Within four hundredths
of a second after the system detects a gear change it opens one clutch and closes
the other. The mechatronics unit ensures that this takes place fast and to a level
of accuracy that would not be possible in a manual transmission. The change of gear
is imperceptible to the driver who is merely conscious of the uninterrupted power.
DSG 7-speed dual-clutch gearbox
Our 7-speed DSG dual-clutch gearbox was a world first. What makes it so innovative
is its pair of dry clutches which have dispensed with the need for the oil bath
of conventional 'wet' clutches. They have been designed to improve fuel efficiency
and driving agility further.
The clutches' dry, organic-bonded friction linings need no cooling. The gearbox
is also very compact and requires less power for the gear selection and clutch servo
system.
Ideal for motorway driving
Adopting 7 speeds meant our engineers could lower 1st gear to improve acceleration
from standstill and raise 7th gear to act as an overdrive function, ideal for motorway
driving. This can save fuel, cut emissions, and means the car runs even more quietly.
Oil volume cut by 75 per cent
The volume of oil in the gearbox has been cut by 75 per cent. Oil circuits are split
into two in an effort to protect purity. As with a conventional manual gearbox,
one circuit is used for cooling and lubrication of the gear teeth, the second feeds
oil to the gear actuators. Since the clutch does not need cooling the quantity of
oil has reduced from 7 litres in the 6-speed DSG 'box to just 1.7-litres in the
7-speed system. The result: improved efficiency rating for the gearbox and lower
fuel consumption.
Innovation
DSG