You can't argue with the figures.
They may not offer the same degree of driver satisfaction, but the new “double-clutch” autos are certainly lightning fast.
The next challenge for car makers will be to engineer the same kind
of drive experience as a manual into these transmissions - a view shared
by the head of BMW's M GmbH division Ludwig Willisch.
The development of the dual or double clutch transmission dates back to World War II.
The concept was invented by a bloke called Andolphe Kegresse just before the outbreak of hostilities.
The first working model however was developed by Porsche in the 1980s.
The PDK (Porsche Doppelkupplung) transmission made its debut in the
Porsche 956 and 962 Le Mans race cars as well as the Sport Quattro S1.
A dual clutch transmission (DCT) is a semi-automatic transmission with separate clutches for odd and even gears.
The outer clutch drives the odd numbered gears, while the inner clutch drives the even numbered gears.
Shifts can be accomplished without interrupting the delivery of
engine power, by applying the engine's torque to one clutch just as the
engine's torque is being disconnected from the other clutch.
A twin-clutch gearbox eliminates the torque converter used in traditional autos.
Dual clutch transmissions use wet multi-plate clutches, similar to the clutches used in traditional automatics.
But a seven-speed version that uses dry clutches, like those usually
associated with manual transmissions, will be been introduced by
Volkswagen with its new Golf and Jetta.
Getrag which makes the seven-speed transmission in the new M3 is also said to be developing a dry DCT.
Although dual clutch transmissions offer superior performance, they
simply don't deliver the same degree of driver satisfaction that comes
from operating a manual transmission in a sports car.
That's because they just don't offer the same degree of driver
involvement, because there's nothing quite like the feeling of punching
the clutch and ramming home the shift at precisely the right moment.
The next challenge for manufacturers will be be the engineering of some physical effort/involvement into shifting gears.
BMW's figures show that the DCT transmission offered in the latest M3
is faster than any previous offering including the SMG box in the E46
M3.
The SMG or Sequential Manual Gearbox reduced shift times to 80
milliseconds and this figure was further reduced to 65 milliseconds in
the later M5 sedan.
With the latest seven-speed M Double-Clutch Transmission with
Drivelogic however there is no longer any interruption of power when
changing gears.
Looking at the acceleration times for the M3, the E46 SMG posted 5.2 seconds for 0-100km/h.
But the latest E92 model does the dash in just 4.6 seconds.
The same car in six-speed manual form is good for 4.8 seconds.
Ludwig believes the manual will disappear altogether eventually, but
for the time being he said that manual alternatives will continue to be
offered.
At the moment BMW M has several projects on the go including the
development of a new production model based on the Concept CS four-door
coupe.
It's the second standalone model to come out of the M division, by that we mean one that is not based on an existing BMW model.
Prior to this it put together the M1 Homage sports concept, shown for
the first time earlier this year year at Italy's Concorso d'Eleganza
Villa d'Este.
We were invited to take part in a long and wide-ranging discussion with the BMW M boss this week in Germany.
In all likelihood we will see M versions of the 1 Series, X6 and
perhaps a mid-engined competitor for Audi's R8 super car based on the M1
Homage.
It also paves the way for the production of other standalone models in the not too distant future.
As quick as the new double-clutch transmissions are, Ludwig agrees they lack the feel of a manual.
In this respect he agrees there is still room for improvement, but
believes a manual transmissions will continue to be offered for the
foreseeable future.
“We build cars for customers and there are still a number of customers that like a manual transmission” he said.
“I think with time the double clutch transmission will be the
solution for the M3. It's faster and it is technology that is in racing.
“I think the stick shift will go away in the future. DCT is something
that can't be beat. It's faster in acceleration, its smoother than an
automatic gearbox and it's more efficient than any other gearbox.
“You could say that a few years ago that it was always a decision
between sportiness or comfort, or sportiness or more efficiency -but
this transmission does so many things at the one time.
“On the other hand especially in the United States we have so many
customers that like to being involved with the car and to show that they
are able to shift manually and so on. Therefore it makes sense for a
car like the M3 at the moment.”
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