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http://wardsauto.com/print/technology/new-9-speed-pushes-tech-limit-gm-says
Like the old 6-speed units, which GM refined over the years and expects to continue applying to its vehicles into the near future, the 9-speed was developed through a partnership with crosstown rival Ford.
Both automakers also derive 10-speed variants from the work. Ford brought that gearbox to market recently in the F-150 large pickup, while GM got first dibs on the 9-speed. GM's first application of the 10-speed will be in the '17 Chevy Camaro ZL1, a 640-hp supercharged version of the sports coupe due later this year in the U.S.
[...] In-house logics software inside a 32-bit transmission control module handles all shift events for smooth, precise ratio changes, GM says. It also monitors transmission performance and compensates for wear in parts such as the clutch plate to maintain consistent performance over time.
"This transmission shifts very smoothly, very precisely," Kline says.
The controller is mounted outside the gearbox to reduce packaging and manufacturing complexity, and it pulls vehicle-specific calibration from the cloud to be added to the core program as the car or truck exits the assembly line. It also enables manual shift control and grade logic, GM says.
The 9T50 features a wider 7.6:1 overall ratio, compared with 6.0:1 in its 6-speed predecessor, a deep 4.69 first gear for off-the-line performance and a tall 0.62 top gear for fuel-efficient, low-rpm highway cruising and optimal NVH.
Sixth gear is equivalent to eighth gear on the new transmission, too, so compared with the 6-speed the 9-speed offers two fuel-saving overdrive gears. Seventh gear is the direct-drive gear, while ninth gear is in use up to 52% of the time.
While the article doesn't say, my guess is that the design is also optimized for automatic/robotic assembly — even though the manufacturing plant is in Mexico.
(Score: 0) by Anonymous Coward on Tuesday January 03 2017, @03:24PM
Have infinite gear ratios, but so far have been unreliable for most auto manufacturers. I think Subaru and Nissan are the only ones that don't have problems. GMs CVT transmissions were so bad they didn't last 20k miles, and they stopped using them.
(Score: 0) by Anonymous Coward on Tuesday January 03 2017, @03:34PM
The reported application for Chevy was in a high performance over 600 horsepower car - this car will also develop substantial torque. There is no CVT I know of that handles high levels of torque which is why you only find them on cars and a few crossover type SUVs. Nothing with a CVT in consumer hands on the road is handling many hundreds of lb-ft of torque.
You won't see CVT on a Camaro of truck anytime soon. Electric drive will probably beat that out.
(Score: 0) by Anonymous Coward on Tuesday January 03 2017, @04:00PM
CVTs can't handle a decent amount of power, that's why you don't see them on many vehicles with more than 200 HP, or even that much.
(Score: 2) by ledow on Tuesday January 03 2017, @04:06PM
Something I didn't know:
CVT was banned from Formula 1 as it was felt that the best funded team would just win hands-down with one.
Given the driver that Formula 1 is to modern car equipment a few decades after, and that people have been making CVT for the last 100 years, and still include it on models (including things like the Prius), I don't think that we can say it's so obviously unreliable that nobody would touch it.
CVT was also popular on trucks for a long time.
I don't think that it's an inherently unreliable technology, just that we've spent a lot more money and time on standard transmissions than on CVT, because it's just cheaper and easier to take that route.
But if we're getting into fuel efficiency, various and even multiple engine types in the same vehicle, then CVT holds promise still.
(Score: 2) by Rivenaleem on Wednesday January 04 2017, @10:42AM
Something I too didn't know, but really are we surprised anymore, Leonardo da Vinci conceptualized a CVT back in 1490. https://en.wikipedia.org/wiki/Continuously_variable_transmission#Planetary [wikipedia.org]
(Score: 1) by jrmcferren on Tuesday January 03 2017, @05:47PM
The only thing with the Subarus is the 2010 to 2012 Legacy (and Outback) have issues with the CVT torque converters, they usually fail under warranty so it is an inconvenience more than anything. I unfortunately can't say anything about 2013 and 2014 due to fact that I have a 2012. The replacement torque converter in mine works better than when the car only had a few thousand miles on it (and it's been about 40,000 since replacement) so the replacement should fix it.
(Score: 0) by Anonymous Coward on Tuesday January 03 2017, @07:04PM
The first time I test drove a Subaru with a CVT I thought the transmission was AFU. It's definitely different if you never drove one before. When I ordered a new Saturn Vue, the only choices in 2004 was a CVT or 5-speed manual. I got the 5-speed, and good thing because the CVTs were breaking down after a few thousand miles.