A     B     C     D     E     F     G     H     I     J     K     L     M     N     O     P     Q     R     S     T     U     V     W     X     Y     Z

All Tests

Automatic Transmission

That there are at least four types of transmissions and three of them are automatic, should be sufficiently known by reading these pages. Therefore, sensitive is the distinction between continuously variable transmissions and Direct Shift Gears or 'dual clutch transmissions', from VW as the first manufacturer in 2003. With up to seven speeds (pictured below) there is so far gear change without interruption of traction.

But we want to deal with the further development of the classic speed automatic transmission. Provided, it still has a converter, this has usually a converter clutch with one or even two torsional dampers. There are possible two more gears than with DSG currently (see picture below).

The shifting comfort of this automatic transmission is superior to the DSG in shifting ease, which dominates in turn regarding the consumption. Case of the consumption tests the differences to the manual transmission are no longer significant, however, the automatic transmisions may shift in test as they want, while the shift points are required for all engines equal when manual transmission. Therefore, engines with more capacity, the preferred partners for speed automatics, perform relatively bad compared with the smaller.

So the stepped automatic transmission is now more reserved for the higher vehicle classes, it is in additional charge but about twice as expensive as DSG. It can compete in terms of speed of the gear change, when the torque converter is completely replaced by a multiple disk clutch. This then also creates space for an additional electric drive (hybrid - see picture below).

The competition regarding the consumption is fuelled towards the DSG meanwhile by more gears with an unprecedented overdrive layout. Some saloons of the upper middle class or above could reach easily within its engine rotational speeds more than 400 km/h, if only they would have enough performance.

Which brings us to a special type, the race-automatics (8-speed - picture above). Thus here, too, the change towards the automatic the, however, without the heavy and starting power guzzling converter with its oil. Also the then usual clutch with diameters up to 270 millimetres and 2 to 6 friction surfaces is taboo here. Instead, the clutch is similar to the in Formula 1, thus small, compact with significantly more friction surfaces

ZF promises total up to 15 percent weight savings, for example, by an oil pan made of carbon. Anyway the requirements of a racing automatic transmission are quite different from those in the series. Thus, the overdrive layout is ceased completely. The eight speeds remain in a narrow spread. A vibration absorber at the transmission input dampens motor unevennesses.

Sidemap - Technik Imprint E-Mail Datenschutz Sidemap - Hersteller