[rgowani]

Audi's DSG

Ferrari uses one. So does BMW. Now Audi has joined the club with, in my pinion, the best automatic manual gearbox in a production car and maybe one of the best transmissions ever built. Those are big words but this transmission shifts better than an automatic and shifts faster than a manual gearbox, while letting the driver have all the economy, control and the fun. Here's where to find one and how it works.
Audi has this transmission available in their 250 horsepower 3.2 TT Quattro. It is a manual gearbox that shifts automatically, passing power through to the Quattro all-wheel drive powertrain. Inside the car, it looks more like an automatic transmission. There is no clutch pedal. The shifter looks like an automatic transmission, with Drive position and a spring-loaded Tiptronic manual shift position. Paddle-style shift levers at the steering wheel can also shift the transmission and will put the gearbox into manual mode even though the console mounted shifter is still in the automatic position. A dash display shows if the transmission is in automatic mode or the manual gear selection.

Start your driving experience by simply placing the shifter in Drive. A Sport mode is available that will delay upshifts and downshifts for more performance in Drive mode. Step on the gas pedal and the car pulls away from a stop just like any automatic transmission but without using a torque converter. As the transmission automatically upshifts, the progression is smooth. Unless you knew, most drivers would think this car has an automatic transmission. The only sound heard from the transmission is a soft sshhfftt as the shifts occur. This sound comes from the oil flow as it engages the clutch for the next gear.

Inside the computer controlled gearbox there are four shafts: two input shafts and two output shafts. The input shafts are concentric, with one shaft passing through the centre of the other hollow input shaft. There are two multi-plate clutch packs similar to those found in automatic transmissions. Each clutch pack connects one of the input shafts to the engine, so depending upon which is applied, either one of the two input shafts can transfer power. An oil pump at the rear of the gearbox supplies hydraulic pressure for the clutches.

The speed gears are divided between the two output shafts. First, third, fifth and reverse gear are on one output shaft while second, fourth and sixth gears are on the other shaft. Synchronisers are moved by the computer to lock each of the speed gears to their output shaft as required. Each output shaft has a pinion gear that drives the differential.

When the driver places the shift lever in drive, First gear is engaged inside the transmission, but the clutch doesn't engage until the driver steps on the gas. Because the clutch is running in oil, it can slip without burning up, allowing the car to creep along in first gear just as an automatic would. Step harder on the gas and the clutch is fully applied. A neat feature of the control system allows the driver to step on the gas and brake at the same time. Audi calls it Launch Control and it allows F1-type starts. In Sport mode with both pedals pressed, the engine revs to 3200 rpm. Release the brake and the car launches in drag strip fashion.

With the transmission engaged in first gear, the computer locks second gear to the other output shaft, but the input shaft clutch for that gear is not engaged. When it is time to shift, the computer releases the clutch for the first gear input and engages the clutch for the second gear input. In preparation for the next shift, the computer now shifts from first to third gear but leaves its clutch disengaged until the shift is requested. As the car's speed increases, the computer continues to pre-select the next gear so all it has to do is switch clutches. There is no grinding, no delays, and no shock.

By monitoring driving style, the computer predicts whether the driver will request an upshift or downshift next so it can pre-select the correct gear. It is possible to fool the computer by driving erratically, but even if the wrong gear is pre-selected it only takes a fraction of a second for it to catch up. This transmission shifts fast, with shift times in the .03 to .04 second range. Even an excellent driver has trouble matching that consistently, and this transmission can do it all day long.

This transmission concept is not new. Audi tested and won with the concept in their Sport Quattro Rally car at Pike's Peak Hill Climb in 1985. It's taken a long time to get to the street, and I hope to see much more of it soon.

Article By Jim Kerr

[ported_head]

definitely, at this rate, manuals seem doomed. DSG is a brilliant innovation, and i can't wait to do a presentation on in in college sometime man. Porsche's Tiptronic and BMW's SMG2 gearboxes are brilliant too, though they do not technically work the same way as DSG. i guess someday we might just have to mourn the death of manuals.

[rgowani]

I dont think they will ever remove the Manual. I mean however fast the Auto goes I would still like to do some Crazy Antics in My car.

[ported_head]

of course dude...dont get me wrong, id take a manual gearshift over any other type available anyday. but then it's not really upto us now is it?

[Rehaan]

Wow RG,

now i understand how it works.... amazing.

I agree with u guys. A "pure manual" as i refer to it is just beautiful in concept and execution, plus i feel its the most involving and fun!

cheers.

[rgowani]

Rehaan but I dont think this will ever remove the Stick Shift BUT its a really nice Innovation. It will be suberb to use on the Drag Race wht do u think? U dont lose any power while it changes Gears and in Manual a person will be changing gears which will make a lose an avg 1 sec only changing gears. Guys have u heard about *the Launch Control of the BMW M3 with SMG2 Gearbox?? U press the Accelerator and it revs to 3500 RPM and when u leave the Stick it goes like the Wind. Would have loved it on the SL55 AMG heheheheh.

[team suzuki]

Europe may have long resisted the automatic gearbox,but it remains a fact that using a manual tramnsmission in stop-start city conditions is no longer a sensible option.Dual clucth transmission offer an increasingly popular way forward for the european driver

New environmental and fuel efficiency legislation combined with major advances in electronics and manufacturing techniques have paved the way for a flood of new automated transmission technologies, including high-performance AMTs, dual-clutch transmissions (DCTs), CVTs for smaller vehicles and the highly innovative new technologies such as Torotrak and the Antonov Automatic Drive. The most likely winner (that will replace traditional automatics and boost market penetration of automated transmissions generally) will be the dual-clutch, pre-select DCT concept, for its combination of refinement, efficiency, low cost and driving satisfaction.

The direct shift gearbox, powershift gearbox, twin-clutch gearbox are just a few of the terms used to describe the dual-clutch gearbox. The gearbox concept combines the advantages of a conventional manual shift with the qualities of a modern automatic transmission. It originated in motor sport and is characterised by having two part gearbox units, which operate the odd and even gears, respectively. It means that when changing gear, the engine torque is transferred continuously from one gear to the other. The result is gentle, jerk-free gear changes with the same relaxed driving style found in an automatic combined with the efficiency of a manual transmission.

For some time, BorgWarner has been working on dual-clutch systems. The VW Group pioneered this technology and continues to push dual-clutch technology in Europe. VW co-developed the six-speed twin-clutch gearboxes (branded DSG) with BorgWarner, making use of the supplier's DualTronic wet-clutch and control-system technology. In addition to its performance and fuel economy benefits, one of the interesting things about this dual-clutch is the fact that it can be "tuned" via software thereby changing the personality from sporty to limo-comfortable.

Earlier this year, Volkswagen updated its DSG, adding an extra speed and swapping units immersed in oil for a new pair of dry clutches. VW said the switch to dry clutches saves weight and improves the efficiency of the system while making the new gearbox more compact. Available in addition to, rather than replacing, the existing six-speed unit, the new seven-speeder is designed to operate under moderate power and torque loadings. It will be launched with a new 122ps 1.4-litre petrol TSI engine and will subsequently be offered with the 1.9-litre Tdi turbodiesel with particulate filter. In the Golf hatchback, compared with the six-speed manual transmission, the new seven-speed DSG auto brings a 10g/km CO2 saving (down from 149g/km to 139) and a fuel economy improvement of over 3mpg (combined 44.8 mpg for manual and 47.9 for seven-speed DSG). Compared with the six-speed DSG, the new unit's lower gears are more closely spaced, giving improved in-gear acceleration to aid overtaking while the higher gears are lengthened to reduce load on the engine and maximise economy. As with the six-speeder, of which over a million have been produced since launch (it is also offered by other VW group brands Audi ,Skoda and Seat, the new seven-speed system features a hill-hold function to aid starts when the vehicle is on an incline.

BorgWarner says it has a 'unique new dual-clutch transmission for developing markets and small cars' in the final development stages. Working in conjunction with several Asian automakers, BorgWarner says it will be providing patent-pending dual-clutch transmission architecture that delivers fuel efficiency in an affordable package ideal for the growing small car demand in developing markets. "Drivers in developing markets like China and India are looking for the ease of using an automatic transmission in an affordable vehicle," said Dr. Bernd Matthes, president and general manager, BorgWarner Transmission Systems. "Up until now, the complexity and cost of automatic transmissions made it impractical to package this option in smaller cars".

BorgWarner says it is significantly reducing the complexity of the transmission hardware. "The competition in this fast-growing and high-potential market segment is fierce and extremely motivating," Matthes added. "Together with our OEM partners, we are working to craft affordable, differentiating systems that distinguish our customers' products from their competition and keep BorgWarner at the forefront of transmission technology." Working with these partners, BorgWarner is currently testing and refining its first phase transmission hardware and controls software. BorgWarner expects production implementation of its new compact dual-clutch transmission design within two to three years. The patent-pending "power split" design of the new transmission uses a large number of common and simplified parts and modules which enhance the affordability of the transmission, the ease of packaging in small vehicles and the manufacturability of the transmission in emerging markets. The small vehicle segment is expected to grow 30% over the next five years from about 19 million to almost 25 million cars.

Germany's LuK is also working on its core components, the dual clutch, actuation system and relevant software. "The main advantage of a dual clutch transmission," said Norbert Indlekofer, president and CEO of LuK Group and president of Schaeffler Group Automotive's Transmission Systems division, "is that changing gear is possible without torque interruption. This creates a very dynamic yet economical driving experience. The LuK double clutch has been delivered to Volkswagen in series production since January 2008.''

LuK's double clutch is made up of two clutches located on two drive shafts. One clutch operates the uneven gears - first, third, fifth and seventh - whilst the second controls the engagement and disengagement of the even gears - second, fourth and sixth - together with reverse. To take an acceleration manoeuvre in second gear as an example, the third gear is already pre-selected in the other sub-gearbox so that changing gear now becomes a particularly speedy, sporty manoeuvre that does not involve any loss of traction. The gear change is triggered electronically and implemented by means of hydraulic actuators. Torque superimpositions on gear changing and the fact that the individual clutches open and close within a fraction of a second mean that the driver is hardly aware of the gear change process.

Last June, Ford's European unit became the latest to adopt a twin-clutch automatic transmission which it is branding PowerShift. The new six-speed box is available initially for the Focus and C-Max ranges coupled with the 2.0-litre TDCi diesel engine in 110 and 136ps tunes. The system uses a standard automatic gear selector in the centre console with the usual P, R, N and D settings and a manual-shift option. Volkswagen pioneered six-speed twin-clutch gearboxes (branded DSG) and group stablemate Audi is now launching new seven-speed versions for both transverse and longitudinal mounting. Mitsubishi is also adopting the technology and will soon launch the first SUV with this type of transmission.

Chrysler's new dual-clutch transmission, developed with Getrag, made its debut in international markets outside North America last spring in the 2009 DodgeJourney and Avenger and 2009 Chrysler Sebring, delivering claimed fuel economy improvements and a CO2 emissionsreduction of 6%. A commitment to dual-clutch transmission technology is part of the company's powertrain offensive, announced last year. This technology improves fuel economy and CO2 emissions by reducing parasitic losses by eliminating the torque converter and using synchronisers instead of shift clutches. The dual-clutch transmission will be mated to a [bought-in Volkswagen] two-litre turbo diesel engine. VW offers this engine its own models with a similar dual-clutch gearbox it calls DSG for direct shift gearbox.

Prospects for DCT shifting up a gear
Manufacturers are predicting steady growth for DCT over the next few years. BorgWarner says it expects production of its dual-clutch transmission modules to increase 500% over the next six years, a key driver of the company's growth. At full-launch of announced programmes under contract in 2012-2013, the company will be providing its DualTronic technology to an expected 2.3 million dual-clutch transmissions annually. That's up from 450,000 dual-clutch transmissions produced this year. BorgWarner reckons that its "dramatic growth" would be driven by Bits position in dual-clutch transmission technology with awarded business from transmission and automakers around the world. These include programs with VW, Audi, Bugatti SAIC, and a Japanese automaker.
"With legislation driving issues like fuel economy and emissions reduction, and consumers looking for performance and drivability enhancement, the demand for dual-clutch transmissions is increasing," said BorgWarner transmission systems president and general manager Bernd Matthes.

Ralph Bast, vice president, passenger cars, Powertrain Division, ZF Sachs AG, told us: "In Europe, we expect a rising demand for the DCT and a total market volume of 1.4 to 2 million units per year. In North America, we also expect a wider penetration but only up to a maximum volume of approximately 1 million units per year." As far as the Asian markets are concerned, Bast added: "Especially in Japan the DCT concept will probably be rather limited to the sports cars segment due to the wide acceptance of CVT transmissions in the Japanese market. Our expectations forecast a market volume of up to 100,000 units per year until 2015. In China, we also expect a rising demand but with a certain delay."

Source:Matthew Beecham,just-auto

[gkrishk]

Can the technical gurus on our forum give us a comparison of the 2 forms of automatic transmission that have recently reached our shores?

The direct shift or dual clutch gearbox (DSG) is favoured by the European marques, Audi-VW group, Porsche, Ferrari, and is also found in the petrol Ford Fiesta.

The continuously variable transmission (CVT), conceptualised by Leonardo da Vinci five hundred years ago (he also invented the differential) has been refined by many Japanese firms and is used by Honda, Nissan and Toyota.

Both designs use electronics in their control systems unlike the old 'slush box' auto which uses an energy wasting torque converter to connect the engine to the gears.

I would like to know if there is any info out there that compares DSGs and CVTs in terms of reliability, longevity, efficiency and drivability.
Which is "better"?

[shashank.nk]

Originally Posted by gkrishk

Can the technical gurus on our forum give us a comparison of the 2 forms of automatic transmission that have recently reached our shores?
I would like to know if there is any info out there that compares DSGs and CVTs in terms of reliability, longevity, efficiency and drivability.
Which is "better"?

Here are a few videos explaining CVT and DCT (Dual Clutch transmissions) that i've found very helpful.It helps you get a basic understanding of how it works

http://www.youtube.com/watch?v=SQLeKdZWGI4

http://www.youtube.com/watch?v=oOciX6kdexE

[gkrishk]

Here are a few videos explaining CVT and DCT (Dual Clutch transmissions) that i've found very helpful.It helps you get a basic understanding of how it works

Thanks for the videos.
But my question was, how do they compare to drive and how do they compare in terms of reliability?

[Jeroen]

Originally Posted by gkrishk

Thanks for the videos.
But my question was, how do they compare to drive and how do they compare in terms of reliability?

Here's my two cents:

The CVT and DCT are fundamentally very different. The early CVTs had one weak spot and that was the drive belt. They used to snap. That wasn't all that big of a problem, because there where two, left and right, but it did happen and it was a costly repair.

As far as I know with the modern CVT that has been fixed for quite a while. CVT work on a very special push/pull chain and as far as I know they've proven very reliable. Because of this special chain they are able to apply these transmission to higher torque and that's meant these CVT have found their way into the truck segment as well. Which is probably a good measure of success in terms of reliability.

There have been lots of issue reported with the DCT. Personally I've owned cars with DCT and I have never had any issues whatsoever. The driving experience between CVT and DCT is very different though.

I was never that much of a CVT fan. Engine revs a lot, but you get continous acceleration. The DCT when accelarating smoothly give you the same continous acceleration but they do shift so you get a more "natural feeling", Even though you might hardly feel it, you can see the engine RPM dropping as the box shift.

So, personally I would still favor the DCT over a CVT. The CVT and the subsequent push/pull chain has been pioneered very much by a country man of mine: Huub van Doorne and his company DAF en van Doorne Transmission.

Unfortunately, my generation of Dutchmen will remember DAF as mostly a "car for old women". I know, highly politically incorrect these days. But that's what it was. In those days, real men did not drive a CVT, they shifted manually!!

So in the Netherlands the DAF with its CVT was always associated with this stigma. My mum did not care, she loved to drive her DAF and later it became the Volvo 300-series that used the same technique.

Jeroen

[ajmat]

Originally Posted by Jeroen

Unfortunately, my generation of Dutchmen will remember DAF as mostly a "car for old women". I know, highly politically incorrect these days. But that's what it was. In those days, real men did not drive a CVT, they shifted manually!!

So in the Netherlands the DAF with its CVT was always associated with this stigma. My mum did not care, she loved to drive her DAF and later it became the Volvo 300-series that used the same technique.

Jeroen

I used to go to school in a DAF 55 and later a 66, I could not figure who whined more, the car or the my friends mother driving it!

[Jeroen]

Originally Posted by ajmat

I used to go to school in a DAF 55 and later a 66, I could not figure who whined more, the car or the my friends mother driving it!

I can well imagine.

Here's a nice Anorak fact on the DAF: They can reverse as fast as they can go forward. Admittedly they did not go that fast forward, but still.

So the Dutch being the Dutch immediately put this to good use and introduced DAF reverse racing. Started in the early eighties and continues to date. I am surprised there are still DAFs around to reverse round a circuit, but apparently there are!

Enjoy:

http://www.youtube.com/watch?v=S7ipFApsFec

[gkrishk]

The Japanese companies and other technology innovators have brought CVTs far ahead from the DAF rubber v-belt days. See http://en.wikipedia.org/wiki/Continu...e_transmission.

The development of steel belts(http://auto.howstuffworks.com/cvt2.htm) has brought reliability to the pulley and belt CVT and electronic control systems make them work better, just as DSGs(DCTs) can't work without their computer control systems.

CVTs are robust enough for tractors and combine harvesters. They have been even been used by Volvo, Mercedes, Jeep, Ford and BMW(and just about any other manufacturer) in some models. CVTs have been banned from use in Formula 1 racing in 1994 because they made cars too fast!

But how are they to drive compared to DSG?

[Jeroen]

Originally Posted by gkrishk

The Japanese companies and other technology innovators have brought CVTs far ahead from the DAF rubber v-belt days. See http://en.wikipedia.org/wiki/Continu...e_transmission.

The development of steel belts(http://auto.howstuffworks.com/cvt2.htm) has brought reliability to the pulley and belt CVT and electronic control systems make them work better, just as DSGs(DCTs) can't work without their computer control systems.

CVTs are robust enough for tractors and combine harvesters. They have been even been used by Volvo, Mercedes, Jeep, Ford and BMW(and just about any other manufacturer) in some models. CVTs have been banned from use in Formula 1 racing in 1994 because they made cars too fast!

But how are they to drive compared to DSG?

yes, come a long way, and the steel belt was still pioneered (and patented) by van Doorne, the original DAF designer/producer. That was already quite a while ago, so many have jumped on the band wagon and managed to improve.

They still drive like the old DAFs but with less noise. Initially very high torque with the engine reving, so you're very fast out of the blocks so to speak. But you still might get the feel that it starts running out of puff. Whereas on with DSG the acceleration just goes on and on.

At the end of the day probably down to personal preference mostly.

I do like the DSG box. Had a few. Very smooth under normal day to day driving condition and when you put the hammer down it really shifts.

Having said that, I'm always amazed how some more convential autotransmission boxes seem to be able to deliver identical smooth driving experience. Even on my 12 year old Jaguar you'd think the old ZF box acts/feels as a DSG box. A big factor must be the engine low rev torque of course. V8's have plenty.


Jeroen