 Sequential transmission
Yes, you would be right if you felt confused by the headline of this new chapter. We just had that. Doesn't a dual clutch transmission belong to the group of sequential
transmissions? Yes, it does, but still there are others.
Just note that sequential transmissions also exist without a dual clutch. An example of this would be the R Tronic of the Audi R8, which optionally replaced the manually shifted
six-speed transmission before the dual clutch transmission was introduced in 2012.
However, caution is advised when mentioning only sports cars as users of sequential gearboxes because, for example, normal transporters are also included, such as the
Mercedes Sprinter. Where does this strange-seeming selection come from? First of all, there is the basic idea of offering a kind of inexpensive automatic.
It sounds easier than it is, but more on that in a moment. First of all, you 'only' replace the clutch pedal with an actuator that can be accessed with variable pressure and the two
directions of movement of the shift lever via on/off operators.
That would now be the cheaper solution for vans instead of fully automatic. But why do people prefer this solution for expensive sports cars? Because the automatic transmission
has a component on board that tends to interfere with the consistent delivery of torque, the torque converter.
That would now be the cheaper solution for vans instead of fully automatic. But why do people prefer just this solution for expensive sports cars? Because the automatic
transmission has a component on board that tends to interfere the torque converter with the consistent delivery of torque.
The sequential gearbox is a step towards short shifting distances. These can then be shortened again using a sport mode and of course a possible wrong switching by the driver
with expensive consequential damage is now ruled out.
As an additional advantage, it is also possible to install a multi-plate clutch with a smaller diameter, which in turn results in a lower center of gravity together with dry sump
lubrication. So there are enough reasons not to use the cumbersome fully automatic system in a sports car.
In theory, the manual transmission can remain, possibly with another gear added. A reinforcement would be good, but a driver can also release the clutch so quickly that the
drivetrain thuds or the wheels spin slightly.
Are there still vehicles that have not been converted to dual clutch transmissions, where the shift pause has then been completely rationalized away? Yes, for example with the
12-cylinder Lamborghini, which is not called 'Ultimae' for nothing, i.e. the last one without hybridization. The will certainly also change the transmission.
So what does it look like, perhaps the final stage of development for the serial transmission? What is initially impressive is the high pressure, probably always over 40 bar, which
is probably necessary to withstand the enormous counterforces, especially at the clutch.
You will probably have to expect then a certain amount of leakage within the valve block and, as a driver, you have to make sure that the hydraulic pump does not start too often
and break down more quickly. The system also needs a non-sophisticated but effective venting system that prevents the hydraulic oil from leaking out.
Actually, if there is too much leakage, a hydraulic block like this doesn't need to be replaced at all, just the valves because they all contain O-rings for sealing. You can perhaps check the holes into which they are screwed,
but as a rule replacing all the valves would have to be sufficient; they are already expensive enough.
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