Never ones to shy away from a good argument – even if it is someone else’s – we just have to poke our noses into
the debate that’s occurring over at The Truth About Cars
concerning VW’s dual-clutch transmission (DCT).
To start things off, Mr. Farago argues that the DCT (he uses the VW trademark “DSG”, or Direct Shift
Gearbox) should signal the end for manual
transmissions. His colleague Bob Eaton responds by claiming that the DCT is just
another variation on the automatic, and makes it clear that his favorite horse in this race is the familiar planetary
slushbox.
We, of course, have our own opinion, so keep reading if you’re curious.
To begin, I’d like to point out that the DCT doesn’t employ any overrunning clutches (also known as
“sprags” or “mechanical diodes”), at least not in the strictest definition of the term, and this
pokes a fairly sizeable hole in Elton’s third-to-last paragraph. Traditional automatics use such devices to allow
the engagement of two or more gears at the same time; the one that attempts to spin the output shaft the fastest is the
one that transmits the power to the road. This is why automatics provide no transmission braking when Drive is
selected. DCTs, on the other hand, depend on the smooth handover of power through two coaxially-mounted clutches, with
elaborate mechatronic controls being the only thing preventing a gear-shredding catastrophe (it’s for this reason that
DCTs employ normally-open clutches, so that a power failure results in a free-spinning drivetrain). Therefore,
there’s really no reason to claim that a DCT is just another variation on the automatic architecture; in fact, the
overrunning clutches in many modern automatics have been replaced by clutch-to-clutch shifts, just like a DCT.
The other important point to make about DCTs is that they’re built using production processes much like a
traditional manual transmission. Many of the internal components of a DCT resemble those of a manual – much more so
than an automatic, in fact. As such, it’s significantly easier to take capital equipment that’s currently manufacturing
manuals and use it for DCT production rather rework the same equipment to build planetary automatics. Considering the
huge amount of production capacity currently available for manuals, especially in regions like Europe, this could
have enormous impact on the direction of future transmission trends. We’ll soon see DCTs from manufacturers other than
Borg-Warner and yes… some will even make their way into U.S.-badged vehicles.
I think where Eaton, Farago, and myself lie in agreement, though, is that manuals are dead. The lines between
an “automatic” and a “manual” will be erased over the next decade or so (maybe less), with
mechatronic systems doing the dirty work through a combination of electric and hydraulic actuators. The time is right,
and many would argue that it’s been right now for at least of couple of decades. In many cases, wider
gear ranges and wet-clutch launch systems will replace the torque converter; frankly, this has already happened to some
extent with progressively-locking multiplate locking converters. At this point, everything’s “automatic,” and
that term ceases to hold any specific meaning.
A huge factor in this, of course, is that the future growth potential in the car industry lies almost entirely in
developing nations. If someone has never driven a car before, does it make sense to complicate the task with two
additional driver control devices and a difficult-to-master technique involved three of the user’s limbs? This hardly
sounds like a recipe for success.
Drivers may still have some means of “manual” input, but these will be treated as suggestions, just as is
the case with modern electronic throttle control (ETC) systems. The difference between a vehicle that is responsive to
driver inputs and one that is not will largely be a function of software, and that should be very exciting to
technologically-savvy consumers, as it’s much easier to change a few lines of code than it is to fit a short-throw
shifter to a manual transmission, or go digging through the valve body of an automatic. Sure, some will complain,
but we’ll simply file away those folks in the same category as those who that haven’t yet managed
to wrap their heads around making the transition from carburetors to EFI. I might even suffer a pang of
nostalgia as I think about the joy of digging through a pan of ATF while looking for a check ball, but I assure you it
won’t last for long.