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Automakers hope to save millions of dollars with joint development

Ford and General Motors have announced that they have teamed up to jointly develop a new generation of advanced 9- and 10-speed transmissions that will be used in cars, crossovers, SUVs, and trucks.
 
The automakers say that the new transmissions will increase both performance and fuel economy. Engineering and development work for the transmissions is currently underway.

“Engineering teams from GM and Ford have already started initial design work on these new transmissions,” said Jim Lanzon, GM vice president of global transmission engineering. “We expect these new transmissions to raise the standard of technology, performance and quality for our customers while helping drive fuel economy improvements into both companies' future product portfolios.”

Automakers need every edge they can get to meet the looming federal CAFE guidelines set to go into effect over the next several years. With a greater number of gear ratios available in the transmission, the engine can operate at more efficient RPMs, which in turn leads to improved fuel economy.
 
Some industry analysts believe that a nine-speed automatic transmission could increase fuel economy by five to ten percent compared to the same vehicle using a six-speed transmission.
 
The two companies have collaborated on transmission technology in the past. Ford and GM previously collaborated to build a six-speed transmission for front-wheel drive cars. Ford currently uses the six-speed transmission and vehicle such as the Fusion and Edge. GM uses the transmission in the Malibu and Cruze among others.
 
Chrysler is currently using an eight-speed automatic transmission in some of its automobiles, including its popular line of trucks.

Source: GM



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RE: Continuously Variable Transmission (CVT)
By alpha754293 on 4/15/2013 1:10:49 PM , Rating: 2
DISCLAIMER: I am speaking on behalf of me and not my employer.

From an automotive engineers perspective, based on what I've learned about them, although I don't have anything to do with them or their development - there are several reasons why high number of gears would be preferred over CVT.

Here's what I think:
CVTs work because they depend on friction to transmit torque. Friction - generally, in mechanical components is treated as a parasitic loss, which is, in short - just plain bad. So the problem with developing CVTs is how do you distinguish between good friction (friction that's required to propel the vehicle forward) from bad friction (the parasitic loss kind)? And being able to reliably predict what happens is a bit of an issue.

You can always make the chain stronger in a CVT, but it gets a LOT heavier for the higher loads. CAN it be done? Yes. Absolutely. But it's probably not recommend. (I couldn't find any ACTUAL examples of off-highway CVTs; but there's probably some that are buried deep within certain respective skunkworks.)

The basics of automatic transmission design actually isn't that complicated. Well, it is and it isn't. The fundamental geartrain (the planteary gear system) is quite well known (and even different forms of it like Ravigneaux vs. LePelletier etc.) is quite well understood (in terms of how they work). So, it's operation is pretty simple/straightforward. And you can quickly get more gear ratios by the multiplicative effect of geartrains. For example, if you have a double-Ravigneaux (each Ravigneaux should give you three speeds because of the double planet gears), 3*3 = 9 speeds. If they don't use all of them, there's usually some other type of constraint/restraint (like packaging all of the components) that would limit the actual number of planets/suns/rings that can be locked.

The controls get more complicated. And the fluid carrying module also gets a LOT more complicated.

But the thing with having a lot of gears is well a couple of things: 1) You really get peak shock torque loading in low speeds (standing start in 0-60). As you get higher and higher up in gears (say changing from 7-8 or 8-9) - the reality is that even at wide open throttle, the torque difference won't nearly be as great, which means you can size the gear to the torque carrying capacity plus some safety factor or the DIFFERENCE in torque carrying capacity. (The chances that going from 9-8 via WOT is going to break your transmission is REALLY REALLY slim. Your engine speed doesn't increase that much so your torque likely isn't going to jump by that much either. It's a lot "harder" if say...you jump from 9-5.)

The other reason is because people complain about the transmission not "shifting" with CVTs. yeah...People actually do say that. So, CVTs end up having to be programmed with "shift points" where it causes noticeable changes in torque, which really reduces the efficiency or the point of having a CVT to begin with.

And you can size all the components to be quite small, and if you go with a different steel alloy, you might be able to get away with using a higher strength steel or a different coating/heat treatment (for example) which also allows you to reduce the size even further. You run into some size limits particularly with the clutches in the clutch packs. (Those still rely on surface area for action; although that's changing too. Ever so slightly.)


RE: Continuously Variable Transmission (CVT)
By Colin1497 on 4/15/2013 4:01:23 PM , Rating: 2
"The other reason is because people complain about the transmission not "shifting" with CVTs. yeah...People actually do say that. So, CVTs end up having to be programmed with "shift points" where it causes noticeable changes in torque, which really reduces the efficiency or the point of having a CVT to begin with."

I've always assumed that in cars with this ridiculous CVT programming to avoid "CVT drone" that they would offer you an efficiency mode to override the stupid fake gear programming.

Anyone with a CVT car have this? Or are you stuck with fake gears?


RE: Continuously Variable Transmission (CVT)
By cyberguyz on 4/15/2013 5:10:39 PM , Rating: 2
While I won't own a car with a CVT, I have driven them. What I don't like is that when you put your foot into them tthey initially rev up then settle back down to that really boring drone. You just don't get the same seat-of-pants feel that you get with gears (manual, auto or dual clutch). CVTs are just plain freaking boring to drive.

Maybe it is just me having grown up with 4 decades of geared vehicles. Perhaps the younger, less ingrained drivers will enhance CCVTs, but for me, I will take Ford's quirky dual clutch auto (though I have had absolutely zero issues with mine) over a cvt any day.


By alpha754293 on 4/19/2013 3:07:33 PM , Rating: 2
DISCLAIMER: I am speaking for myself and not my employer.

@Colin1497

"I've always assumed that in cars with this ridiculous CVT programming to avoid "CVT drone" that they would offer you an efficiency mode to override the stupid fake gear programming.

Anyone with a CVT car have this? Or are you stuck with fake gears?"

Oh...if only.

@cyberguyz
See my reply above about having an extra controller for the variable hydraulic pressure valve. CAN it be done? Yes. For pennies-per-trans? *shrug* mehhh...

If you have intimate working knowledge of a particular CVT, and you have intimate engineering knowledge, you probably override that. Whether it'll last 250,000 customer equilvalent miles (or whatever) - well...mehhh....

It's an exciting time to be an automotive engineer right now because there are SO many options which leads to SO many more possibilities with all of the different combinations that you can come up with and then trying to find out what's the best, most optimal solution based on how you defined and weighed each of the performance targets and criteria.

It has to paired with your engine so that it's suitable. If you're doing a lot of ultra urban driving; doing that in a Ford GT would just be maddening cuz you'd hardly get out of 1st. But if you're doing 50,000 miles a year, 80% of which is highway (like I do) - I'm going to spend all of that time in top gear, so what does it matter whether it's a CVT or not?


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