DSG
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.
* paddle shift not standard with all DSGs
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.
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