Two innovations are mainly responsible for the improved performance. The design incorporates four planetary gear sets and five shift elements. Only two shift elements are opened in each gear which leads to considerably lower drag losses. Besides the improved efficiency, the transmission also features a higher total ratio. Further, modern torsional vibration damping systems in the torque converter also have a positive impact on consumption and CO2 emissions.
ZF has also designed the gearbox as a modular unit that can be used in a number of configurations including AWD without the need to change the basic transmission concept. We’re also likely to see the gearbox appear in future hybrid models, similar to the systems developed by Mercedes-Benz and BMW, which utilize a crankshaft starter generator. Conventional hybrids that use a parallel configuration like the Toyota Prius can also benefit from the new design.
The next several months will be interesting to see whether traditional automatics will remain more popular than the latest dual-clutch systems being rushed to market by most of the major carmakers. With the number of gears growing each year for new transmissions, we wonder if gearbox manufacturers will continue to try and outdo each other just like the razor blade companies.
Reader Comments
Thu May 3 2007 9:22 AM
docdang says
"With the extra cogs on board, the new gearbox improves mileage rates by 6% over the second generation six-speed transmission..."
If you add more gears and mechanics, wouldn't you be adding more weight?
Thu May 3 2007 9:33 AM
admin says
The new gearbox is similar in size to the older 6-speeder and at the same time transmits power more effectively and has higher gear ratios, in the long-run saving fuel.
Thu May 3 2007 9:08 PM
Gus says
Wow, the ever increasing complexity of these devices is astonishing.
We will surely soon see the end of independent repair and transmission shops. The only ones who will be able to work on these engines and transmissions are the dealers, with costs to match...
But it is inevitable technology, no doubt about it.
Fri May 4 2007 9:03 AM
biturbo says
This is lame!
Increasing the number of gears is a cheap trick. Yes, it may get slightly better economy during boring sedated driving. But if driving like that why not buying a Prius?
No torque converter slushbox can compete with the dual-clutch transmissions like DSG.
ZF wake up!
Fri May 4 2007 11:59 PM
admin says
biturbo - it's also there for comfort, not just for fuel efficiency. At the moment DSG is great if you want a sporty drive and shift paddles yourself, but I'm willing to bet most people don't. Auto-mode DSG is pretty awful.
Leave a Comment
Login or register to leave comments.
Please keep your comments on topic. Your involvement is governed by our Privacy Policy and Terms.