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Old 28th February 2010, 20:38   #1
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Default GM applies for patent of its new 9 speed automatic transmission-full details

Yes, you read it right, 9 speed automatic.

Full details on the patent application here:

9-Speed Transmission - Patent application - The transmission has a plurality of members that can be utilized in powertrains to provide nine forward speed ratios and one

And, the third headlined article here:

Autoblog Weekender: Gumbo Edition — Autoblog
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Old 28th February 2010, 22:00   #2
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On the face of it, sounds like 3 gears too many. Somehow even when I drove the 7G-tronic on the Mercs, I didn't really feel the need for number seven. It does help with the FE while cruising at highway speeds, with very low rpm's for those speeds in seventh.
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Old 29th September 2012, 15:25   #3
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Default Re: GM applies for patent of its new 9 speed automatic transmission-full details

Just read this article on Yahoo News that GM and Ford are jointly developing 9 and 10 speed transmissions-

http://in.news.yahoo.com/gm-ford-9-s...--finance.html


The new BMW models seem to have 8 speed auto box. 9 and 10 speed should be an interesting development.

Could anyone throw some light on what is the impact on gear ratios, fuel efficiency, torque handling capacity of the transmission, engine size, maximum power etc ?



Cheers,
Yogesh.
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Old 29th September 2012, 15:34   #4
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Default Re: GM applies for patent of its new 9 speed automatic transmission-full details

Quote:
Originally Posted by yogeshnagpal View Post
Just read this article on Yahoo News that GM and Ford are jointly developing 9 and 10 speed transmissions-

http://in.news.yahoo.com/gm-ford-9-s...--finance.html


.
Are you sure? GM and Ford? The former and latter are biggest rivals known to whole industry. They compete with each other by locking their horns very fiercely and now, they are developing 9 to 10 speed automatics together for their vehicles. Auto Industry has never been so exciting! I am sure both must have their secret intentions in this deal but AFAIK, this couldn't be possible. Let's wait and watch!

Last edited by S@ndy : 29th September 2012 at 15:35.
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Old 29th September 2012, 19:15   #5
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Default Re: GM applies for patent of its new 9 speed automatic transmission-full details

I don't understand the need for so many gears.6 gears are sufficient if the engine has good amount of torque and if the gear ratios are optimum.Only heavy duty trucks really need n number of gears to help them pull the heavy load in different conditions like slops as well as highways.Guess we will have performance cars with 18 gears in the near future if this trend continues
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Old 29th September 2012, 20:34   #6
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Default Re: GM applies for patent of its new 9 speed automatic transmission-full details

I guess this would effectively allow them to install smaller more fuel efficient engines and not let the driver notice any loss of power.
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Old 29th September 2012, 21:20   #7
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Default Re: GM applies for patent of its new 9 speed automatic transmission-full details

Quote:
Originally Posted by S@ndy View Post
Are you sure? GM and Ford? The former and latter are biggest rivals known to whole industry.
The New York Times carries the same information, so it is confirmed. According to the NYT, this is not the first time the two giants are collaborating on transmissions.

Quote:
G.M. and Ford already are successful in working together on transmissions. In 2002, they agreed to share design and production of a new 6-speed automatic for front-drive vehicles. The resulting Ford 6F and G.M. 6T70 transmissions, introduced in 2006 and numbering over 8 million produced, use common mechanical parts but have electronic controls specific to their applications. The independently developed electronics tailor the transmissions to nearly 30 different models.

If the relationship evolves into a joint production program, “it would have huge manufacturing cost and volume advantages over all the competition,” because of the combined size of G.M. and Ford and their supply base, said Skip Nydam, who tracks transmission developments for ND-Automotive, an industry analyst firm.
I have pasted some interesting technical information from the same article. It seems even the Americans are becoming increasingly interested in fuel economy.

Quote:
An important factor in the move to seven and more gears is the transmission’s ratio spread — the numerical relationship between first and top gear (called the overall ratio spread), or between adjacent gears — for instance, third and fourth gears.

Adding more gears is the only way to have a large overall ratio spread (for both good acceleration and quiet highway cruising) along with a small ratio spread between gears (to keep the engine revving at its best power level for a given road speed). The higher the number, the better. The new 9-speeds will have a ratio spread close to 10, compared with a typical 6-speed’s ratio spread of about six.

Packing more gears into the compact transmission housings used in smaller vehicles — along with the hardware needed to deliver smooth, imperceptible shifts — is an increasingly tricky challenge, engineers say. They are designing the gearsets to “nest” within each other to save space.

However, there is only so much space available under the hood of subcompact and compact cars with front-wheel drive, in part because their transmissions are positioned across the chassis, rather than lengthwise as in trucks, large S.U.V.’s and most sports cars and large luxury sedans. The limited width between the front wheels restricts how wide the transmissions can be — and the number of gears that can fit inside.

The lack of space to package seven and more gears is one reason that subcompacts like the Ford Fiesta and Chevrolet Sonic don’t achieve higher fuel efficiency than the larger Ford Focus and Chevy Cruze. It’s also why compacts like the Focus and Cruze can’t top the economy of the midsize Fusion and Malibu. (The longer vehicles also have lower aerodynamic drag, which helps overall efficiency.)

The tiny Chevrolet Spark had only enough space in its engine compartment to accommodate a 4-speed automatic. To quickly satisfy demand for more gear ratios from American customers who don’t want the standard 5-speed manual, G.M. plans to offer a continuously-variable transmission, supplied by Jatco, a Japanese C.V.T. specialist, in coming Sparks. The compact C.V.T. essentially offers an infinite number of gear ratios, enabling the tiny car to close the fuel-economy gap with its larger, more expensive stablemates.

Last edited by johnjacob : 29th September 2012 at 21:28.
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Old 30th September 2012, 09:34   #8
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Default Re: GM applies for patent of its new 9 speed automatic transmission-full details

Sometimes I wonder with the increasing number of settings of AT units are we not approaching a good old CVT in some ways - continuous or infinite variations. Only due to the stepped action rubber banding is reduced.
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