The document discusses the clutch system used in the Bugatti Veyron sports car. It uses a dual clutch transmission (DCT) system, which has two clutches that allow two gears to be engaged simultaneously for seamless gear shifts within 150 milliseconds. The twin-clutch gearbox combines the performance of a manual transmission with the convenience of an automatic. It consists of two wet multi-disc clutches, seven forward gears, and computer-controlled shifting for optimal performance and fuel efficiency.

1. The Clutch of Bugatti Veyron
Sarth Jauhari | Sohan Nair | Vivek Nair
Theory of machines - II
Prof. Gajanan Thokal
By

2. 1
AIM
To Study the Clutch system of Bugatti Veyron.
INTRODUCTION
Bugatti Veyron 16.4 has crossed the speed of 400 km/h and has set a new record of 406 km/h in the
world of sports cars. But, the question is how do they do it? Though, the very confidential production
house of Bugatti Veyron cars hasn't told us much about their mechanisms but they have surely told about
the future technologies which have been used to build this masterpiece. The Bugatti Veyron uses Dual
Clutch Transmission (DCT) system.
For years, the idea of a dual clutch transmission languished in transmission engineers’ desk drawers. That
fairytale slumber continued into the late 1990s, when the idea was revived by VW. The 2003 debut was in
the Golf R32 and the Audi TT.
This technology provides one of the fastest gearshifts of 150ms in the world.
THE CLUTCH ITSELF
The twin-clutch gearbox of the Bugatti Veyron combines the dynamic advantages of a manual gearbox
with the convenience of an automatic to an as yet unparalleled level of perfection.
The man who invented the dual-clutch gearbox in 1939 was a pioneer in automotive engineering
Adolphe Kégresse.
CONSTRCUCTION
The gearbox has a twin clutch that is composed of two wet-running multi-disc clutches.
In the construction of dual Clutch Transmission system, the need for a Torque convertor is eliminated as
it is not a fully automatic system.
Two interlocking transmission shafts, each linked to a separate clutch, allow for power shifting without
torque interruption.

3. 2
WORKING
The dual clutch system consists of two separate clutches, which allow two gears to be engaged at the
same time. One of the gears is transferring torque, while the next is already pre-selected.
One of the two clutches engages the odd-numbered, the other the even-numbered gears. This
principle enables gear shifts to be made without interrupting the power flow and keeps the shift times
extremely short. While the first clutch is transmitting the power, the second clutch is ready to engage
the next gear, which is preselected electronically.
This computer-controlled system is identical to the sort of system found in a Formula 1 car or a Champ
car. There is no clutch pedal or shift lever for the driver to operate -- the computer controls the clutch
disks as well as the actual shifting. The computer is able to shift gears in 0.2 seconds.
DESIGN, DEVELOPMENT ANDMANUFACTURE
There are no fewer than 660 part numbers for the driveline’s 1200 components and the system breaks
new engineering ground – particularly in its use of seven forward speeds and twin clutches, and in its real-
time role in determining high speed vehicle dynamics through its active rear differential and Haldex
coupling.

4. 3
TECHNICAL SPECIFICATIONS
The transmission is unique, in particular because it has to harness about twice as
much torque as any previous sports-car transmission. It has:
• Seven gear
• A dual clutch system
• Sequential shifting
• A paddle-driven, computer-controlled shifting system
ADVANTAGES
There are a few both important advantages when it comes to dual-clutch transmission. First of all,
as you can see for yourself, there's the reaction time. The whole assembly works incredibly fast,
less than a hundredth of a second as in the case of DSG designed by Volkswagen.
Secondly, there's the fuel consumption. The dual-clutch clutch gearbox improves the fuel
consumption, especially at cruising speeds because it automatically adjust its settings to maintain
the desired speed but keeping the fuel efficiency at the highest possible level.

5. 4
Last but not least, there's the comfort it provides. Although it doesn't work as smoothly as a
traditional automatic transmissions and sometimes you may actually feel the shifting process a
little bit, a dual-clutch transmissions is much more appropriate for city driving than a regular
manual unit that requires the driver to change gears every time when needed.
Better fuel economy
Convenient to use even at high torque and speeds
DISADVANTAGES
Some drivers prefer the experience of a manual transmission with a proper manual clutch, and will
never give that up. Having a clutch gives a driver the ability to modulate engine revs, making it
possible for the driver to easily kick out the back end of a rear-wheel drive car or to burnout on a
launch. This full control is irreplaceable.
Other limitations are inherent because a DCT uses a fixed amount of gears, and therefore the
engine can’t always remain in its most powerful range. Continuously Variable Transmissions (CVT)
have been created to fix this, but are often limited to engines with lower power outputs. Also,
these transmissions have not been well received by enthusiasts due to the non-traditional feel,
and have been mostly implemented in hybrids and other fuel conscious vehicles.
CONCLUSION
Thus, the twin-clutch gearbox of the Bugatti Veyron combines the dynamic advantages of a manual
gearbox with the convenience of an automatic to an as yet unparalleled level of perfection.
SOURCES
Ricardo Quarterly Overview – Q2 (2006)
www.bugatti.com
www.howstuffworks.com