4 6 2 1
R 7
3 5
The 911 | Transmission
Multi-plate clutch 1
Multi-plate clutch 2
Differential
All-wheel drive models
Engine
Front axle
Rear wheelRear wheel
Porsche Doppelkupplung (PDK) PDK function diagram
How Porsche Doppelkupplung
(PDK) works.
The crankshaft transmits engine
torque to the dual-mass flywheel
which is then channelled through
the clutch housing and onto the
multi-plate clutches, or to be more
precise, the outer disc carrier.
Under oil pressure, clutch 1 closes
and forms a frictional connection
with input shaft 1.
The torque is now transmitted
through the differential to the
rear axle or, in the all-wheel drive
variants of the 911, the front and
rear axles.
At this stage, PDK has already
preselected the next gear. Engine
torque is already acting on the
other outer disc carrier and, in
response to a gear change signal,
the overlap shift is initiated, i.e.
as clutch 1 opens, clutch 2 closes.
The non-positive connection with
input shaft 2 is established, and
power is transmitted to the
wheels.
The gear which is engaged is dis-
played on the instrument cluster.
PDK has distinct benefits. The
very rapid gearshifts, with no
interruption in the flow of power,
produce faster acceleration.
Driving feels even sportier and
more dynamic, and agility is
increased. Depending on the
gearshift programme, the gear
change is optimised for comfort
or for sporty handling.
The compact dimensions of the
gearbox reduce rotational masses
which means a more direct engine
response, and the system is more
lightweight.
This, along with the long-ratioed
7
th
gear, helps to achieve reduced
fuel consumption and emission
figures comparable with those of
a manual gearbox. In conjunction
with the engines featuring direct
fuel injection (DFI), it has been pos-
sible to reduce fuel consumption
by up to 13 % and CO
2
emissions
by up to 15 % (compared with the
previous model).
With the optional Sport Chrono
Package Plus, PDK is enhanced
by the ‘Launch Control’ and
‘motorsport-derived gearshift
strategy’ functions (p. 74). In
essence, PDK combines sporti-
ness with efficiency and comfort.
What could be more appropriate
to a Porsche 911?
Semi-gearbox 2
(2nd, 4th,
6th gear)
Semi-gearbox 1
(1st, 3rd, 5th, 7th,
R gear)
