Some companies like Volkswagen have decided to ditch the conventional automatic transmission for an all-twin clutch offering when it comes to a gearbox for those who do not want to bother with shifting and clutching, but many companies still swear by the automatic transmission with planetary gearsets and a torque converter as they usually offer much smoother shifts and thus are usually more suited for a comfortable drive.
Twin clutch and single clutch automated manual transmissions are catching up in terms of smoothness of shifting but the torque converter is also making progress when it comes to shift speed and fuel efficiency. ZF Sachs recently celebrated the 20 millionth torque converter to roll off its Schweinfurt plant.
The latest in ZF’s torque converter technology is the use of twin torsional dampers in the torque converter to allow the lock-up clutch to close at an earlier point in time. This results in faster shift times and better fuel efficiency due to the fact that the mechanical linkage thanks to the lock-up clutch is active more often rather than having power transferred through the oil. This quick-shifting gearboxes have appeared in some higher end BMW vehicles such as the BMW X5.
So yes, conventional automatics apparently aren’t going to disappear anytime soon, with ZF Sachs recently investing another 80 million Euros at its Schweinfurt plant to expand capacity. The plant will also be making ZF’s new 8-speed automatic transmission, that’s said to be making a production appearance on an upcoming V12 760i version of the F01 7-Series and a future Rolls Royce.
Though ZF appears to be committed to improving and pushing the limits of how far the conventional auto can go, ZF will also be venturing into the world of dual clutch transmissions. Two twin clutch boxes are said to be in the works – the 7DCT50 and the 7DCT70 which seems to indicate 7-speed units. Too bad it missed the M DCT boat – BMW’s 7-speed twin clutch box is sourced from Getrag, which traditionally supplies manual boxes to Munich.
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good in a sense it makes changing gear smoothly and fuel efficiency…
This twin-clutch thingy, is really going to be a sunset technology soon. Once electrics and fuel cell powerplants are cheap and reliable enough for mass consumers, it would not be needed anymore.
Maybe I’m too optimistic, but my take is, those in the auto industries should not spend huge resources on RND and invest lot of monies to build factories and machineries for it. A small amount is sufficient, mainly to keep the competitors at bay and to keep people buying new cars (who would buy new cars if there’s no new things in them?) – but that just about it. Spend the rest of the resources towards the new ‘sunrise’ technologies. What say you guys?
electric also had a gear lah alihms!
I second you bmpower…
If say no gearbox for sure your electric more will ‘kong’ much earlier, cause too much pressure on high revolutions..
Alifz said,
September 15, 2008 @ 10:32 am
I second you bmpower…
If say no gearbox for sure your electric more will ‘kong’ much earlier, cause too much pressure on high revolutions..
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Er, what do you mean by the “too much pressure on the high revolution”?
Electric cars would need gears no doubt – but not in the conventional sense of it (several fixed gears ratios coupled with manual or auto transmissions). The gears would probably by fixed at a certain ratio. Electric motor has enough torque at all rpm – thus eliminating the need for gearboxes. Electric motors inherently have high torque even at low speed. Electric motors can ‘idle’ at zero rpm!
For fuel cell, it depends. For internal combustion engine (ICE) design that uses hydrogen instead of fossil fuels, then those conventional gear boxes are necessary. But for majority of car manufacturers, the design that they pursue, bypasses ICE completely. There’s a lot of moving parts on ICE and on transmission setup – thus higher power losses & also a lot more parts to maintain. So, it makes more sense to bypass it altogether and use the fuel cell to powers electric motors directly – thereby no need for gearboxes.
With the exception of The Veyron and GTR, I think DCT still have to deal with high torque machines. With more experiences with the tradional auto gearbox, it is clear that ZF believes there is room for improvement.
Personally, in time when DCT can be heavily mass produced, then Auto box will be disappearing.
alihms:
electric motor have their top rev about 2500rpm
even though it have many torque from below 100rpm
but it still need a gear box to push the car to moved
all these automatic nonsense, i just use manual