However, in the past few years, 5-speed automatic was increasingly popular in European prestige saloons, now covering virtually all Mercedes and BMW, thus improved performance and economy a bit.
Another improvement was the adoption of electronic control. A computerised automatic transmission has different shifting programs for different requirements : Economy, Sport and Winter (Snow) are the most popular choices. For instance, if you select Sport mode, the gearbox upshift at higher engine speed to make better use of power band, hence enhances acceleration. On the contrary, choosing Economy mode will ease the pressure to the engine, thus enhance smoothness, quietness and save fuel.
Some computerised autos even have learning function (some uses Fuzzy logic). They memorise the driving habit of the driver through reading the input from throttle, rev counter etc. Then adapt their programs to suit the driving style of the driver.
Future of Automatic Transmission
Not too optimistic, because CVT and the likes of Ferrari / Alfa's Selespeed manual-based gearbox are improving rapidly in these few years.
As CVT becomes stronger and stronger, hopefully within a few years it will be suitable to medium-sized or even luxurious cars. By then, CVT's smooth manner and better fuel-efficiency will make automatic transmission looking useless. Moreover, production cost is just half way between manual and automatic gearbox.
Manual-based gearboxes with automatic mode will also eat into auto's market. Not only being lighter and cheaper, their superior performance must be attractive to keen drivers. Given a little bit more development in shift quality, they can also benefit traditional auto-equipped cars like Mercedes.
In the near future,
transmissions still have an edge in handling high torque for high-end
cars. Continuous improvement to performance, cost and weight may extend
its life span into the next decade. German transmission expert ZF has
the world’s first 6-speed automatic gearbox for production cars. It
be adopted by the new BMW 7-series. Not only offering 5-7% reduction of
fuel consumption and improvement to performance, most impressive is
it uses 30% less components and weighs 13% less than the existing
|Advantage:||Smooth and quiet shifting, ease of use|
|Disadvantage:||Heavy, large, costly, slow and fuel-inefficient|
|Who use it ?||Nearly all automatic transmissions now are computerised|
Even in manual mode, the computer may intervene under harmful conditions. For instance, if the driver let the rev exceeding redline without upshift, the computer will shift automatically.
conjunction by Porsche, ZF and Bosch. Porsche originated the idea, ZF
and Bosch responsible for the electronic control.
In 1995, a newer version called Tiptronic S launched. It offers fingertip control button mounted on the steering wheel spoke, thus allow the driver can to shift without loosing concentration on the road.
|Advantage:||Feels more involving than pure automatic|
|Disadvantage:||With all the disadvantages of automatic. No faster.|
|Who use it ?||