VISVESVARAYA TECHNOLOGICAL

UNIVERSITY
BELGAUM, KARNATAKA- 590014

A TECHNICAL SEMINAR REPORT ON

“DUAL CLUTCH TRANSMISSION”
Submitted in partial fulfilment for the award of the degree in
Bachelor of Engineering
in
MECHANICAL ENGINEERING
Mr. MOHAMMED EJAZ HUSSAIN B(3VC15ME052)

UNDER THE GUIDANCE OF

Dr. Chandragowda M

DEPARTMENT OF MECHANICAL ENGINEERING

RAO BAHADUR Y MAHABALESHWARAPPA
ENGINEERING COLLEGE
(FORMELY VIJAYANAGAR ENGINEERING COLLEGE,BELLARY)
CANTONMENT,BALLARI-583104(KARNATAKA)
2018-19

1
RAO BAHADUR
Y.MAHABALESHWARAPPA
ENGINEERING
COLLEGE

(Formerly Vijayanagar Engineering

College, Bellary)

CANTONMENT, BELLARY-583104
(KARNATAKA)

DEPARTMENT OF MECHANICAL
ENGINEERING

CERTIFICATE

Certified that the technical seminar work

entitled "DUAL CLUTCH
TRANSMISSION" carried out by MR.
Mohammed Ejaz Hussain B, USN
3VC15ME052, a bonafied student of RAO
BAHADUR
Y.MAHABALESHWARAPPA
ENGINEERING COLLEGE in partial
fulfilment for the award of Bachelor Of
Engineering In Mechanical Engineering of
the Visveswaraya Technological University,
Belgaum during the year 2018-19 . I is
certified that all corrections/suggestions
2
indicated for internal assessment have been
incorporated in the seminar report submitted
in the departmental copy. The technical
report has been approved, as it satisfies the
academic requirements in respect of seminar
report work prescribed for the said Degree.

Signature of the Guide

Signature of HOD

Acknowledgment

I would like to express our regards

and acknowledgement to all those who
helped in making this seminar possible.

I am grateful to the Principal

Kuppagal Veeresh for providing facilities
and untiring Zeal, which constantly inspired
me towards the attainment of everlasting
knowledge throughout the course.

I am deeply in debted to Dr. Kori

Nagaraj, Professor and HOD of
Mechanical Engineering department for the
valuable suggestions and constant
encouragement provided for the successful
completion of the seminar.

I would like to thank our guide,

Dr.Chandragowda M, Assistant professor
of Mechanical Engineering department for

3
the constant guidance for the successful
completion of seminar.

I would like to thank our Seminar

Coordinates Mr.Balaji M Assistant
professor of
Mechanical Engineering department for their
support and encouragement in order to
complete the work of seminar successfully.

Finally, I would like thank all the

staff members of Computer Science and
Engineering department for their guidance
and support . I am also thankful to my family
and friends who continue to give me best
support.

Signature of student
Mohammed Ejaz Hussain B
3VC15ME052

4
 CONTENTS
page no:
 INTROdUCTION .
1-2
1.1 Transmission.
1.2 Purpose of Transmission.
1.3 Clutch.
 Dual clutch transmission.
3-5
2.0 Operation of DCT
 Basic design of Dual Clutch
Transmission. 5-9
3.0 Dual Clutch Transmission
Shafts.
3.1 Multi plate clutch.
 Advantages
10
 Disadvantaged
11
 Controliing of DCT
12
 Dual clutch transmission past,present
and future 12-13
 Applications
14

5
 Conclusions.
15
 Reference.
16

6
INTRODUCTION

1.1 TRANSMISSION

Transmission is the mechanism through which the driving torque of the engine is
transmitted to the driving wheel of the vehicle so that the motor vehicle can move on
the road. The reciprocating motion of the piston turns a crankshaft rotating a flywheel
through the connecting rod .The circular motion of the crankshaft is to be now
transmitted to the rear wheels .It is transmitted through the clutch, gear box, universal
joints, propeller shaft or the drive shaft, differential and axles extending to the
wheels .The application of the engine power to the driving wheels through all these
parts is called POWER TRANSMISSION .The power system is usually the same on
all modern passenger cars and trucks, but its arrangement may vary according to the
method of drive and type of transmission units.

1.2 PURPOSE OF TRANSMISSION:

 It enables the engine to be disconnected from the driving wheels.

 It enables the running engine to be connected to driving wheel smoothly and
without shock.
 It enables the leverage between the engine and the driving wheels to be varied.
 It enables the reduction of engine speed in the ratio of 4:1 in case of passenger
cars and in greater ratio in case of Lorries.
 It enables the driving wheels to be driven at different speeds.
 It enables turning the driving through 90 degrees.
 It enables the relative movement between the engine and the driving wheel.
1.3 CLUTCH
In all vehicles using a transmission (virtually all modern vehicles), a coupling device
is used to separate the engine and transmission when necessary. The clutch
accomplishes this in manual transmissions. Without it, the engine and tires would at
all times be inextricably linked, and anytime the vehicle stopped the engine would
perforce stall. Without the clutch, changing gears would be very difficult, even with
the vehicle moving already: deselecting a gear while the transmission is under load
requires considerable force, and selecting a gear requires the revolution speed of the
engine to be held at a very precise value which depends on the vehicle speed and
desired gear. In a car the clutch is usually operated by a pedal; on a motorcycle, a
lever on the left handlebar serves the purpose.

1. When the clutch pedal is fully depressed, the clutch is fully disengaged, and no
torque is transferred from the engine to the transmission (and by extension to the drive
wheels). In this uncoupled state it is possible to select gears or to stop the car without
stopping the engine.

2. When the clutch pedal is fully released, the clutch is fully engaged, and practically
all of the engine's torque is transferred. In this coupled state, the clutch does not slip,
but rather acts as rigid coupling, and power is transmitted to the wheels with minimal
practical waste heat.

3. Between these extremes of engagement and disengagement the clutch slips to

varying degrees. When the clutch slips it still transmits torque despite the difference
in speeds between the engine crankshaft and the transmission input. Because this
torque is transmitted by means of friction rather than direct mechanical contact.

4. Considerable power is wasted as heat (which is dissipated by the clutch). Properly

applied, slip allows the vehicle to be started from a standstill, and when it is already
moving, allows the engine rotation to gradually adjust to a newly selected gear ratio.

5. Learning to use the clutch efficiently requires the development of muscle memory
and a level of coordination analogous to that required to learn a musical instrument or
to play a sport.
6. A rider of a highly-tuned motocross or off-road motorcycle may "hit" or "fan" the
clutch when exiting corners to assist the engine in revving to the point where it
delivers the most power.

DUAL CLUTCH TRANSMISSION

A semi-automatic transmission (also known as clutchless manual transmission,

dual-clutch transmission, automated manual transmission, e-gear, shift-tronic,
flappy paddle gearbox, or direct shift gearbox) is a system which uses electronic
sensors, processors and actuators to do gear shifts on the command of the driver. This
removes the need for a clutch pedal which the driver otherwise needs to depress
before making a gear change, since the clutch itself is actuated by electronic
equipment which can synchronise the timing and torque required to make gear shifts
quick and smooth. The system was designed by European automobile manufacturers
to provide a better driving experience, especially in cities where congestion frequently
causes stop-and-go traffic patterns

Elaborated form of manual transmission in which two internal shafts, each connected
to the input via an electronically controlled clutch, are coordinated such as to achieve
an uniterrupted flow of torque to the driven wheels during gear changes. As well as
reducing acceleration times, a dual clutch transmission also enchances refinement
over a convectional manual or manual gearbox.
Most people know that cars come with two basic transmission types: manuals, which
require that the driver change gears by depressing a clutch pedal and using a stick
shift, and automatics, which do all of the shifting work for drivers using clutches, a
torque converter and sets of planetary gears. But there's also something in between
that offers the best of both worlds -- the dual-clutch transmission, also called the
semi-automatic transmission, the "clutchless" manual transmission and the automated
manual transmission.
In the world of racecars, semi-automatic transmissions, such as the sequential
manual gearbox (or SMG), have been a staple for years. But in the world of
production vehicles, it's a relatively new technology -- one that is being defined by a
very specific design known as the dual-clutch, or direct-shift, gearbox.

2.0 OPERATION OF DCT

In standard mass-production automobiles, the gear lever appears similar to manual
shifts, except that the gear stick only moves forward and backward to shift into higher
and lower gears, instead of the traditional H-pattern. The Bugatti Veyron uses this
approach for its 7-speed transmission. In Formula One, the system is adapted to fit
onto the steering wheel in the form of two paddles; depressing the right paddle shifts
into a higher gear, while depressing the left paddle shifts into a lower one. Numerous
road cars have inherited the same mechanism.

Hall Effect sensors sense the direction of requested shift, and this input, together with
a sensor in the gear box which senses the current speed and gear selected, feeds into a
central processing unit. This unit then determines the optimal timing and torque
required for a smooth clutch engagement, based on input from these two sensors as
well as other factors, such as engine rotation, the Electronic Stability Program, air
conditioner and dashboard instruments.

The central processing unit powers a hydro-mechanical unit to either engage or

disengage the clutch, which is kept in close synchronization with the gear-shifting
action the driver has started. The hydro-mechanical unit contains a servomotor
coupled to a gear arrangement for a linear actuator, which uses brake fluid from the
braking system to impel a hydraulic cylinder to move the main clutch actuator.

The power of the system lies in the fact that electronic equipment can react much
faster and more precisely than a human, and takes advantage of the precision of
electronic signals to allow a complete clutch operation without the intervention of the
driver.

For the needs of parking, reversing and neutralizing the transmission, the driver must
engage both paddles at once, after this has been accomplished the car will prompt for
one of the three options.

The clutch is really only needed to start the car. For a quicker upshift, the engine
power can be cut, and the collar disengaged until the engine drops to the correct speed
for the next gear. For the teeth of the collar to slide into the teeth of the rings not only
the speed, but also the position must match. This needs sensors to measure not only
the speed, but the positions of the teeth, and the throttle may need to opened softer or
harder. The even faster shifting techniques like powershifting require a heavier
gearbox or clutch or even a twin-clutch gearbox.

BASIC DESIGN OF DUAL CLUTCH TRNSMISSION

A dual-clutch transmission offers the function of two manual gearboxes in one. To

understand what this means, it's helpful to review how a conventional manual gearbox
works. When a driver wants to change from one gear to another in a standard stick-
shift car, he first presses down the clutch pedal. This operates a single clutch, which
disconnects the engine from the gearbox and interrupts power flow to the
transmission. Then the driver uses the stick shift to select a new gear, a process that
involves moving a toothed collar from one gear wheel to another gear wheel of a
different size. Devices called synchronizers match the gears before they are engaged
to prevent grinding. Once the new gear is engaged, the driver releases the clutch
pedal, which re-connects the engine to the gearbox and transmits power to the wheels.
So, in a conventional manual transmission, there is not a continuous flow of power
from the engine to the wheels. Instead, power delivery changes from on to off to on
during gearshift, causing a phenomenon known as "shift shock" or "torque interrupt."
For an unskilled driver, this can result in passengers being thrown forward and back
again as gears are changed.
A dual-clutch gearbox, by contrast, uses two clutches, but has no clutch pedal.
Sophisticated electronics and hydraulics control the clutches, just as they do in a
standard automatic transmission. In a DCT, however, the clutches operate
independently. One clutch controls the odd gears (first, third, fifth and reverse), while
the other controls the even gears (second, fourth and sixth). Using this arrangement,
gears can be changed without interrupting the power flow from the engine to the
transmission.
Sequentially, it works like this:

 A car travelling in second gear is controlled by the inner clutch .Power is

sent to second gear along the outer transmission shaft

 As the car increases speed, the computer detects the next gearshift point
and the third gear is pre-selected.

 When the driver changes gears, the inner clutch disengages and the outer
clutch is activated.

 The power is transferred along the inner transmission shafts to the pre-
selected gear.

Drivers can also choose a fully automatic mode that relinquishes all gear-changing
duties to the computer. In this mode, the driving experience is very similar to that
delivered by a conventional automatic. Because a DCT transmission can "phase out"
one gear and "phase in" a second gear, shift shock is reduced. More importantly, the
gear change takes place under load so that a permanent flow of power is maintained.

An ingenious two-shaft construction separating the odd and even gears makes all of
this possible.
3.0 DUAL CLUTCH TRANSMISSION SHAFTS

A two-part transmission shaft is at the heart of a DCT. Unlike a conventional manual

gearbox, this houses all of its gears on a single input shaft, the DCT splits up odd and
even gears on two input shafts. The outer shaft is hollowed out, making room for an
inner shaft, which is nested inside. The outer hollow shaft feeds second and fourth
gears, while the inner shaft feeds first, third and fifth.

The diagram below shows this arrangement for a typical five-speed DCT. Notice that
one clutch controls second and fourth gears, while another; independent clutch
controls first, third and fifth gears. That's the trick that allows lightning-fast gear
changes and keeps power delivery constant. A standard manual transmission can't do
this because it must use one clutch for all odd and even gears.
3.1 MULTI PLATE CLUTCH

Since a dual-clutch transmission is similar to an automatic, one might think that it

requires a torque converter, which is how an automatic transfers engine torque from
the engine to the transmission. DCTs, however, don't require torque converters.
Instead, DCTs currently on the market use wet multi-plate clutches. A "wet" clutch is
one that bathes the clutch components in lubricating fluid to reduce friction and limit
the production of heat. Several manufacturers are developing DCTs that use dry
clutches, like those usually associated with manual transmissions, but all production
vehicles equipped with DCTs today use the wet version. Many motorcycles have.
single multi-plate clutches

Like torque converters, wet multi-plate clutches use hydraulic pressure to drive the
gears. The fluid does its work inside the clutch piston, seen in the diagram above.
When the clutch is engaged, hydraulic pressure inside the piston forces a set of coil
springs part, which pushes a series of stacked clutch plates and friction discs against a
fixed pressure plate. The friction discs have internal teeth that are sized and shaped to
mesh with splines on the clutch drum. In turn, the drum is connected to the gearset
that will receive the transfer force. Audi's dual-clutch transmission has both a small
coil spring and a large diaphragm spring in its wet multi-plate clutches.

To disengage the clutch, fluid pressure inside the piston is reduced. This allows the
piston springs to relax, which eases pressure on the clutch pack and pressure plate.
2.5 ADVANTAGES

In principle, the DCT behaves just like a standard manual transmission:

 It's got input and auxiliary shafts to house gears, synchronizers and a clutch. It
doesn't have a clutch pedal, because computers, solenoids and hydraulics do the
actual shifting. Even without a clutch pedal, the driver can still "tell" the computer
when to take action through paddles, buttons or a gearshift.
 Driver experience is just one of the many advantages of a DCT. With upshifts
taking a mere 8 milliseconds, many feel that the DCT offers the most dynamic
acceleration of any vehicle on the market.

 It certainly offers smooth acceleration by eliminating the shift shock that

accompanies gearshifts in manual transmissions and even some automatics. Best of
all, it affords drivers the luxury of choosing whether they prefer to control the shifting
or let the computer do all of the work.

Audi TT Roadster
One of several Audi models available with a dual-shift transmission
 Perhaps the most compelling advantage of a DCT is improved fuel economy.
Because power flow from the engine to the transmission is not interrupted, fuel
efficiency increases dramatically. Some experts say that a six-speed DCT can deliver
up to a 10 percent increase in relative fuel efficiency when compared to a
conventional five-speed automatic.

2.6 DISADVANTAGES

 Many car manufacturers are interested in DCT technology. However, some

automakers are wary of the additional costs associated with modifying production
lines to accommodate a new type of transmission. This could initially drive up the
costs of cars outfitted with DCTs, which might discourage cost-conscious consumers.

 In addition, manufacturers are already investing heavily in alternate

transmission technologies. One of the most notable is the continuously variable
transmission, or CVT. A CVT is a type of automatic transmission that uses a moving
pulley system and a belt or chain to infinitely adjust the gear ratio across a wide
range. CVTs also reduce shift shock and increase fuel efficiency significantly. But
CVTs can't handle the high torque demands of performance cars.DCTs don't have
such issues and are ideal for high-performance vehicles. In Europe, where manual
transmissions are preferred because of their performance and fuel efficiency, some
predict that DCTs will capture 25 percent of the market. Just one percent of cars
produced in Western Europe will be fitted with a CVT by 2012.
2.7 CONTROLLING OF DCT

A method of controlling the clutches of a dual clutch transmission during a two-gear

positive downshift, wherein the first clutch drives an initial gear and the final gear and
the second clutch drives an intermediate gear. The torque transfer across each clutch is
controlled so that the torque output of the transmission will be linearly changed over
from the first clutch to the second clutch to cause the engine to track a target engine
speed profile. The method changes over the gears driven by the first clutch from the
initial gear to the final gear as the engine continues to tracks the target speed. The
torque transfer across each clutch is controlled so that the torque output will be
linearly changed back from the second clutch to the first clutch in an inversely
proportional rate to continue to cause the engine to track the target engine speed
profile.

2.8 Dual-clutch Transmissions: Past, Present and Future

The man who invented the dual-clutch gearbox was a pioneer in automotive
engineering. Adolphe Kégresse is best known for developing the half-track, a type of
vehicle equipped with endless rubber treads allowing it to drive off-road over various
forms of terrain. In 1939, Kégresse conceived the idea for a dual-clutch gearbox,
which he hoped to use on the legendary Citroën "Traction" vehicle. Unfortunately,
adverse business circumstances prevented further development.

Both Audi and Porsche picked up on the dual-clutch concept, although its use was
limited at first to racecars. The 956 and 962C racecars included the Porsche Dual
Klutch, or PDK. In 1986, a Porsche 962 won the Monza 1000 Kilometer World
Sports Prototype Championship race -- the first win for a car equipped with the PDK
semi-automatic paddle-shifted transmission. Audi also made history in 1985 when a
Sport quattro S1 rally car equipped with dual-clutch transmission won the Pikes Peak
hill climb, a race up the 4,300-meter-high mountain.
 Porsche 962

Commercialization of the dual-clutch transmission, however, has not been feasible

until recently. Volkswagen has been a pioneer in dual-clutch transmissions, licensing
BorgWarner's DualTronic technology. European automobiles equipped with DCTs
include the Volkswagen Beetle, Golf, Touran, and Jetta as well as the Audi TT and A3;
the Skoda Octavia; and the Seat Altea, Toledo and Leon.

Photo courtesy VM Media Room

Volkswagon Jetta 2.0

Ford is the second major manufacturer to commit to dual-clutch transmissions, made

by Ford of Europe and its 50/50 joint venture transmission manufacturer, GETRAG-
Ford. It demonstrated the Powershift System, a six-speed dual-clutch transmission, at
the 2005 Frankfurt International Motor Show. However, production vehicles using a
first generation Powershift are approximately two years away.
2.9 APPLICATIONS

Trucks and buses

Semi-automatic transmissions have also made its way into the truck and bus market in
the early 2000s. Volvo offers its I-shift on its heavier trucks and buses, while ZF
markets its ASTronic system for buses and coaches. These gearboxes have a place in
public transport as they have been shown to significantly reduce fuel consumption.

In the UK though, semi-automatic transmission has been very popular on buses for
some time, from the 1950s right through to the 1980s, an example being the well
known London Routemaster, although the latter could also be driven as a fully
automatic in the 3 highest gears. Leyland manufactured many buses with semi-
automatic transmission, including its Leopard and Tiger coaches. Fully automatic
transmission became popular with increasing numbers of continental buses being
bought in the UK, and more and more British manufacturers began offering automatic
options, mostly using imported gearboxes, and semi-automatic transmission lost
favour. These days, very few buses with semi-automatic transmission remain in
service, although many are still on the roads with private owners. Modern types of
semi-automatic transmission though are becoming more common, mostly replacing
manual gearboxes in coaches and small buses.

Motorcycles
In addition to the Hondamatic system noted above, Yamaha Motor Company
introduced a semi-automatic transmission on its 2007 model year FJR1300 sport-
touring motorcycle in 2006. Notably, this system can be shifted either with the lever
in the traditional position near the left foot, or with a switch accessible to the left hand
where the clutch lever would go on traditional motorcycles.
3.0 C0NCLUSIONS
New environmental and fuel efficiency legislation coupled with advances in
electronics and manufacturing techniques have triggered new automated transmission
technologies. The most likely winner that will replace traditional automatics and boost
market penetration of automated transmissions will be the dual clutch transmission
(DCT).
4.0 REFERENCES

1. Automobile engineering by R.B. Gupta

2. Automobile engineering by kirpal sing
3. google.com
4. howstuffwork.com
5. wikipedia.com
6. autoworld.com
7. http://www.seminarprojects.com