CHAPTER 5. MIXED DOUBLES. AT ODDS OF EVENS. 2 Km pe Jhagda.
10 Km pe hathapai.
25 Km pe shanti.
Aur 30 Km pe romance.
Un haathon ka milna, humne sambhal kar rakha hai kahin.
Use bana loon apna.
The key to happiness. For me, and my other half.
A revolution in automatic gearboxes. A gearbox that shatters the myth that automatics can't be fun.
- Power sapping torque converter? Eliminated.
- High RPM CVT rubber band effect? Eliminated.
- Drop in pickup and mileage? Eliminated.
- Just 4 and 5 speeds? They are ancient things of the past.
Its official. The Clutch is back.
Yes, I say it again, the clutch is back.
But hey, an AT transmission isn't supposed to have a clutch, isn't it?
"Its an automated clutch, in fact it has two clutches."
:Shockked:
Two. Yes, two is better than one. The law of duality takes a whole new meaning. The odds are stacked adjacent to the evens, as against them.
Welcome to the world of
DSG gearbox. Also called as:
- Direct Shift Gearbox (DSG)
- S-Tronic
- M-DCT (Dual Clutch Transmission)
- Double Clutch Gearbox
- PDK (Porsche Doppelkupplungsgetriebe)
and many more terms used by different manufacturers worldwide.
The basics of dual clutch gearbox and some trivia
(courtesy wikipedia):
A
dual clutch transmission, commonly abbreviated to
DCT (sometimes informally referred to as a
twin-clutch gearbox,
double clutch transmission, or similar variations thereof), is a differing type of
semi-automatic or
automated manual automotive
transmission. It utilises two separate
clutches for odd and even
gear sets. It can fundamentally be described as two separate
manual transmissions (with their respective clutches) contained within one housing, and working as one unit. They are usually operated in a fully automatic mode, and many also have the ability to allow the driver to manually shift gears, albeit still carried out by the transmission's electro-hydraulics.
This type of transmission was invented by Frenchman
Adolphe Kégresse just prior to
World War II, but he never developed a working model. The first actual DCTs arrived from Porsche in-house development, for Porsche racing cars in the 1980s, when computers to control the transmission became compact enough: the Porsche Doppelkupplungsgetriebe (
English:
dual clutch gearbox) (PDK) used in the
Porsche 956 and 962
Le Mans race cars from 1983, and the
Audi Sport Quattro S1 rally car.
A dual clutch transmission eliminates the
torque converter as used in conventional epicyclic-geared
automatic transmissions. Instead, dual clutch transmissions that are currently on the market primarily use two
oil-bathed wet multi-plate clutches, similar to the clutches used in most motorcycles, though dry clutch versions are also available.
The first series production
road car to be fitted with a DCT was the 2003
Volkswagen Golf Mk4 R32.
As of 2009, the largest number of sales of DCTs in Western Europe are by various marques of the German
Volkswagen Group, though this is anticipated to lessen as other transmission makers and vehicle manufacturers make DCTs available in series production automobiles.
In 2010, on BMW Canada's website for the 3 Series Coupe, it is described both as a 7-speed double clutch transmission and as a 7-speed automatic transmission. It is actually a dual clutch semi-automatic.
Overview
In DCTs where the two clutches are arranged concentrically, the larger outer clutch drives the odd numbered gears, whilst the smaller inner clutch drives the even numbered gears. Shifts can be accomplished without interrupting
torque distribution to the driven roadwheels, by applying the engine's torque to one clutch at the same time as it is being disconnected from the other clutch. Since alternate gear ratios can pre-select an odd gear on one gear shaft whilst the vehicle is being driven in an even gear, (and vice versa), DCTs are able to shift more quickly than other cars equipped with single-clutch automated-manual transmissions (AMTs), a.k.a. single-clutch semi-automatics. Also, with a DCT, shifts can be made more smoothly than with an AMT, making a DCT more suitable for conventional road cars.
Clutch types
There are two fundamental types of clutches utilised in dual clutch transmissions: either two wet multi-plate clutches which are bathed in oil (for cooling), or two dry single-plate clutches. The wet clutch design is generally used for higher torque engines which can generate 350
newton metres (258
ft·lbf) and more (the wet multi-plate clutch DCT in the
Bugatti Veyron is designed to cope with 1,250 N·m (922 ft·lbf), whereas the dry clutch design is generally suitable for smaller vehicles with lower torque outputs up to 250 N·m (184 ft·lbf). However, whilst the dry clutch variants may be limited in torque compared to their wet clutch counterparts, the dry clutch variants offer an increase in fuel efficiency, due to the lack of pumping losses of the transmission fluid in the clutch housing.
Clutch installation
There are now three variations of clutch installation. The original design used a concentric arrangement, where both clutches shared the same plane when viewed perpendicularly from the transmission input shaft, along the same centre line as the engine crankshaft; when viewed head-on along the length of the input shaft, this makes one clutch noticeably larger than the other.
The second implementation utilised two single-plate dry clutches which are side-by-side from the perpendicular view, but again sharing the centre line of the crankshaft.
A latest variation uses two separate but identical sized clutches; these are arranged side-by-side when viewed head-on (along the length of the input shaft and crankshaft centre line), and also share the same plane when viewed perpendicularly. This latter clutch arrangement (unlike the other two variations) is driven via a gear from the engine crankshaft.
The Indian Journey of DSG:
The first car to be launched with DSG was, not surprisingly from a company that pioneered this tech, that is VW group. But it was skoda that got this 'box first. In 2006,
Skoda launched its all new second generation octavia, renamed
Laura for the Indian market as the old octavia was repositioned in the lower price bracket. With a 1.9L Pumpe duse motor, 105 bhp is not exactly what you expect from a modern diesel motor but the transmission's mechanism and lightning quick gear changes due to computer controlled timing of the double clutches made it very quick, torquey and kept skoda's reputation for amazing fuel efficiency intact. Surprisingly, despite the AT-only option available initially, demand was strong and the car was on a wait.
But this advance technology is not without its share of drawbacks. VW group's DSG gearboxes are too sensitive for our conditions and somehow the typical Indian driving style of varying rpms took their toll and led to premature failures and huge warranty claims. Skoda'a laura too was a victim of it. Though in subsequent years proper driver training and improved reliability has made this gearbox the enthusiast's choice, it's long term reliability is one thing which needs to be proven in our country.
Skoda's poor after sales and lack of customer concern also remains to blame. But till now, the company has enjoyed decent success with the DSG box.
- The Facelifted laura was offered a DSG gearbox with both a 1.9L 105 hp and 2.0L 140 hp PD engine, the latter in the top end L and K version. This car received a new set of common rail motors which replaced the inferior PD engines and perfectly suited the characteristics of the cog. 2.0L 140 hp motor comes with DSG whereas 2.0L 110 hp comes with manual.
- Skoda's all new second generation superb, launched with 1.8L 7 speed DSG with TSI and 160 PS, 2.0L PD (later CRDI 140 hp) DSG 6 speed and 3.6 VR-6 FSI 6 speed DSG is a stupendous success for the brand and remains the bestselling upper D segment sedan in its segment. Competitive price and equipment levels only add to the appeal.
- Audi's range of cars in the Indian market has DSG gearboxes as standard. Not surprisingly, being a VW flagship. The redesigned TT 3.2 uses a 6 speed s-tronic DSG, the A4 1.8, 2.0 and 2.0 TDI use DSG, the Q5 2.0 TDi uses DSG and the Q7 now also uses DSG. Rest of the lineups continue to use convectional tiptronic gearboxes.
- Mercedes SLS AMG and SL 63 AMG use 7 speed M-DCT wet clutch gearbox.
- BMW M3 also uses M-DCT 7 speed as an option.
- Porsche's facelifted Bosxter S, Cayman S, 911 (carrera/4, targa, turbo and turbo S) PDK all use Porsche version of 7 speed DCT called PDK or Porsche Doppelkupplungsgetriebe. The latest Porsches, the cayenne and Panamera are also equipped with standard PDK on all but their base versions. These cars are much quicker and actually more efficient as compared to their manual counterparts. Same can be said for the TT also.
- The latest Japanese car, the Lancer Evolution X also uses a Twin Clutch SST gearbox, the same info for which can be found on team-bhp's official review link.
- VW offered its DSG box in the jetta 1.9 PD and passat 2.0 PD cars, but poor sales meant that this were replaced with manual equipped versions, that is passat 1.8 TSI and Jetta 2.0 PD respectively. Expect the redesigned versions of these cars to get back the DSG option when they will hit the market shortly along with the redesigned toureag, which too was continued to be available with a DSG in its present avatar.
Globally,
Nissan's GT-R also uses this box. And now
Hyundai too has jumped into foray by launching its in house developed 6 speed DCT transmission, the first application of which will see in its upcoming
VELOSTER coupe.
Fiat DUOLOGIC gearbox
Fiat's pioneering duologic transmission is nothing but a sequential manual gearbox, similar to the BMW's SMG (M5 and M6) gearboxes.
From Fiat:
Normally performance and economy pull in different directions, but the DuaLogic gearbox is designed to make extremely efficient use of the engines to which it is attached, ensuring that they are always working at their peak effectiveness for the task in hand. This translates into better performance and lower fuel consumption, by way of lower exhaust emissions.
The DuaLogic gearbox is technically described as a sequential manual gearbox, which means it has a conventional clutch and gearbox, so there is no power-sapping torque converter and hydraulic gears. Instead there is small, light actuator unit to operate the clutch and move the gears, plus a highly intelligent computer. Thus, the DuaLogic equipped car has the performance and economy of the manual car as a starting point, unlike a conventional automatic which is always at a disadvantage to a manual gearbox given its weight and power-consuming technology. To this already efficient system is added a computer that knows the engine to which it is connected inside-out. The computer ensures that the gearbox is always in the most effective gear for the performance required, maximising both performance and economy capabilities. Indeed, the cars with DuaLogic even know if it is going downhill or climbing a hill and adjusts its changing patterns appropriately.
With the DuaLogic taking over the operation of the gearbox and the clutch, driving is easier and simpler. The driver has the choice of placing the DuaLogic in automatic or manual modes. In automatic mode, DuaLogic does all the work, selecting the gears, operating the clutch and getting the best economy and performance. The driver can also select normal mode or economy mode, with, as the name suggests, the latter selection ensuring that the car extracts every the maximum energy out of every last drop of fuel.
DuaLogic doesn’t just blindly change gears. It has full fuzzy logic, so it can adapt to the driver’s style, matching his changing demands, both his style and changing road conditions. Another feature of the DuaLogic is its ability to assess vehicle deceleration and adjust downshifts.
In semiautomatic mode, for example, the system allows downshifts, particularly when the driver demands a lower gear to take a corner at speed during a sporty drive. In automatic mode, the system anticipates the downshift to ensure the driver can always call on the most appropriate speed to maintain the required comfort level or fuel saving.
With the DuaLogic gearbox in automatic mode, its robotised electronic management system allows the gears to be changed at the time of maximum engine performance. This makes it possible to exploit all the power and torque of the engines and achieve a distinct improvement in acceleration over a manual gearbox.
However, the DuaLogic also has a manual mode where, using the gear lever, the driver can self-select gears to get the maximum pleasure out of driving the car.
DuaLogic also boosts safety. To prevent unwanted gear changes, the system engages neutral when the engine is still running and the door has been opened and DuaLogic device also activates warning lights and buzzers to notify the driver of emergency situations or manoeuvres that are not permitted and could damage the engine or gearbox.
Expect the Fiat to launch the Linea in India with this gearbox as sales stabilise, internationally its available in conjunction with the 1.3 multijet diesel engine and 1.6 multijet in South America. For all its capabilities, the 1.6 will perfectly suit the bill. Perhaps, how about another cup of lavasa with more icing on the cake?:)
But icing the competition for a cakewalk won't be easy.
Perhaps the numbers game just got a whole lot more interesting.
Till then, enjoy this wonderful Sunday evening and chillax without fretting your brains.
Because the game of one upmanship has just began. Find out more about it, in the next chapter, titled "bigger is better."