Porsche 911 Carrera 4 Brochure & Specs page 27

4
How Porsche Doppelkupplung
The torque is now transmitted
(PDK) works. through the differential to the
rear axle or, in the all-wheel drive
The crankshaft transmits engine variants of the 911, the front and
torque to the dual-mass flywheel rear axles.
which is then channelled through
the clutch housing and onto the At this stage, PDK has already
multi-plate clutches, or to be more preselected the next gear. Engine
precise, the outer disc carrier. torque is already acting on the
other outer disc carrier and, in
Under oil pressure, clutch 1 closes response to a gear change signal,
and forms a frictional connection the overlap shift is initiated, i.e.
with input shaft 1. as clutch 1 opens, clutch 2 closes.
The non-positive connection with
input shaft 2 is established, and
6 2 1 3 5
R 7
Porsche Doppelkupplung (PDK)
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.
Multi-plate clutch 1
Multi-plate clutch 2
6
4
2
Engine
Semi-gearbox 2
(2nd, 4th,
6th gear)
Driving feels even sportier and This, along with the long-ratioed
more dynamic, and agility is 7 th gear, helps to achieve reduced
increased. Depending on the fuel consumption and emission
gearshift programme, the gear figures comparable with those of
change is optimised for comfort a manual gearbox. In conjunction
or for sporty handling. with the engines featuring direct
fuel injection (DFI), it has been pos-
The compact dimensions of the sible to reduce fuel consumption
gearbox reduce rotational masses by up to 13 % and CO
which means a more direct engine by up to 15 % (compared with the
response, and the system is more previous model).
lightweight.
7
5
3
R 1
Differential
Semi-gearbox 1
(1st, 3rd, 5th, 7th,
R gear)
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.
emissions What could be more appropriate
2
to a Porsche 911?
The 911 |
Transmission
All-wheel drive models
Front axle
PDK function diagram