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Getrag Begins Series Production of New Powershift Transmission; Up to 20% Reduction in Fuel Consumption Compared to Conventional Torque Converter Automatic

6DCT250
The 6DCT250 transmission. Click to enlarge.

Getrag has begun series production of the newest member of its Powershift transmission lineup, the dry dual clutch 6DCT250, at its plants in Irapuato (Mexico) and Modugno (Italy). The 6DCT250 transmission will first be introduced in the Renault Mégane and the Renault Scénic and for the NAFTA market in the Ford Fiesta.

The 6-speed, front-wheel drive transmission makes reductions in fuel consumption of up to 20% possible compared to a conventional torque converter automatic transmission, according to Getrag. For 2010, quantities of more than 100,000 transmissions are planned; this will increase to more than 400,000 per year by the end of 2011. The 6DCT250 was developed for integration in small- and medium-sized cars.

6DCT250 Transmission
  • Max torque capacity: 240 - 280 N·m
  • Weight: 72-82 kg (incl. damper/DMF)
  • Single-speed reduction gear transmission
  • Installation length: 350-400 mm
  • Ratio 1st gear: 15-18.5
  • Ratio 6th gear: 2.1 - 4
  • Gear spread ratio: max. 7.2
  • The 6DCT250 front-transverse transmission has six forward gears and one reverse gear. The even (2, 4, 6, R) and odd-numbered gears (1, 3, 5) are divided into two partial transmissions. The engine and the two partial transmissions are connected by means of a dry dual clutch.

    The 6DCT250 is versatile in its application. It is applicable for both diesel and gasoline engines, Getrag says, and a start-stop functionality can be installed without any modification or extension of hardware. The transmission can be combined with an all-wheel drive power train and, when coupled with an e-motor, can be applied as hybrid solution.

    With the Getrag Powershift 6DCT250 we will usher in the second era of dual clutch transmissions. Due to the dry dual clutch and the electromechanical actuation, the transmission surpasses even the conventional manual transmission in fuel consumption and CO2 emission.

    —Bernd Eckl, COO of the Getrag Group

    The Modugno plant is responsible for the complete manufacturing of the gear sets for Europe and the assembly plant in Mexico and additionally assembles transmissions for the European market. The Italian Getrag plant was redesigned and restructured for the new dual clutch technology and will be running at full capacity by 2012. The newly built Getrag location in Irapuato is responsible for the assembly, end of line control and delivery of the transmissions produced for Ford and was designed for this task.

    A consistent common-part-strategy allows rapid and cost-efficient adaption to customer needs, Getrag says. Further, all variants can be realized with only one production line type.

    The Getrag Corporate Group. headquartered in Untergruppenbach, Germany, is one of the largest system suppliers for transmissions and powertrain systems worldwide. Its transmission portfolio comprises manual, automated manual and dual clutch transmissions. The powertrain portfolio contains axle differentials, power take-off units and torque management systems. Getrag also offers a range of hybridization and electrification of transmissions and powertrains. In 2009, the Group reached a turnover of €2 billion.

    Comments

    HarveyD

    It seems that most car manufacturers (except GM) switched to similar 6 and 7 speed transmissions for many of their 2008 to 2010 or 2011 models. GM will do it for some 2012 models. Why is GM 2 to 3 years behind others?

    What are the real advantages of 6-7 speeds dual clutch transmissions over CVTs, if any?

    sd

    "What are the real advantages of 6-7 speeds dual clutch transmissions over CVTs, if any?"

    CVTs are friction devices and have continuous friction type loss and wear whereas the dual clutch transmission only exhibit friction loss and wear during the actual shift which takes less than a second. With a CVT, you might get slightly better engine efficiency but the the transmission efficiency is much worse with the CVT. Also with 6 or 7 speeds, the engine efficiency gains are relatively small. In my opinion, the CVT is destined for the scrapheap of history. For an standard IC engine transmission combination, the dual clutch transmission is the way to go. The other interesting combination is the serial electric system that the Chevy Volt will have. This allows the engine to always run at it's optimal point and there is minimal wear as the only transmission elements are the final drive between the motor and the wheels.

    HarveyD

    sd:

    How can you get better engine efficiency or better mileage with a CVT with more transmission friction loss than dual clutch units? If so, the CVT must have certain advantages (cost, weight???)

    Nick Lyons

    @sd:

    You write:

    CVTs are friction devices and have continuous friction type loss and wear whereas the dual clutch transmission only exhibit friction loss and wear during the actual shift which takes less than a second.

    Gears engaged under load are hardly without friction--the profile of one gear tooth slides against its mate. Lubrication reduces the friction, but doesn't eliminate it. Otherwise transmission oil wouldn't get hot--which heat embodies the continuous frictional losses within the transmission (from gears & bearings).

    It may be that belt-type CVTs have higher frictional losses than traditional gearboxes, but I'd like to see the studies that show that. Some belt-type CVT applications (e.g. new Subarus) achieve very good efficiency.

    3PeaceSweet

    Adding an electric motor to a dual clutch transmission seems to be a good idea, it can be added from the other side to the engine allowing the engine to be disconnected for gliding / low speed all electric driving.

    Dual clutch transmissions should be a good match for diesels

    Peter_XX

    HarveyD,
    You got some correct answers by Nick Lyons but maybe no answer to one of the question you asked. A dual-clutch transmission changes gear ratio stepwise; a CVT can change the ratio contiously. Thus, the engine operation point can be more optimal for a CVT while the dual-clutch gives a certain compromise. However, what we are interested in is the total drivetrain efficiency, i.e. the product of engine and transmission efficiency. The total efficiency is most likely higher for a drivetrain with dual-clutch transmission than for one with a CVT. Some of the early dual-clutch transmissions had wet clutches that have higher losses than dry clutches and there are also some other losses to address. In my understanding, the manufacturers are working on that now. You can even find cars where the dual-clutch transmission has better fuel economy than a conventional mechanical transmission. I cannot recall a similar comparison with a CVT but I suppose the future is tough for a CVT.

    Stan Peterson

    I welcome this tiny 6 speed DCT. It should offer a fine transmission for most A segment and B segment cars, being newly introduced to the US auto market.


    It's too bad that 3/4 or more of the US market needs power beyond the capacity of this transmission to handle. C & D and larger segment vehicles most likely have engines too powerful for this particular transmission to handle, with its nominal maximum torques handling capacity of only 185 lb-ft,(250 N-m) or so.

    I look forward to one of its larger siblings being in my next car.

    HarveyD

    Peter XX

    Thank you for the info. Both technologies being close as far as total engine/transmission efficiency is concerned, initial cost, weight, volume, adaptability, ruggedness, durability, ongoing maintenance etc could be important factors to consider.

    I'm not a specialist, but it would seem that CVT units are well suited for smaller, lighter, less powerful vehicles. They have proven to be very durable on Prius and a few other cars using them.

    MG

    Harvey,

    The CVT in Prius (and other Toyota hybrids using HSD system) is not actually a real mechanical CVT (like the ones found in Nissans, new Subarus, Mitsu Lancer, some previous Audi A4), but rather behaves like a CVT from outside (ie provides infinite number of ratios of input and output rpm's), so some authors call it e-CVT.

    HarveyD

    MG:

    Thank you for the info. There are so many different type of CTV/ITV/VDP that it is very difficult to pick the best one. In the not too distant future, BEVs may not have to rely so much on transmissions. In wheel e-motors (Michelin type etc) could do away with what is called transmissions and many other moving parts.

    joookes

    Stan, this transmission is rated for 209 lb-ft. Ford's 2.0L EcoBoost in its mildest form of tune is 200 hp and 207 lb-ft from 1750 rpm. What I'd like to see is that drivetrain in the Fusion.

    The comments to this entry are closed.