CONTINUOUSLY VARIABLE TRANSMISSIONCONTINUOUSLY VARIABLE TRANSMISSION(CVT)

NARAYAN .H.MSEMESTER -81BM07ME060

MECHANICAL ENGG.DEPT.

BMS COLLEGE OF ENGINEERINGBMS COLLEGE OF ENGINEERING

INTRODUCTION HISTORY NEED OF TRANSMISSION CVT TYPES OF CVT USE OF CVT HOW DOES CVT WORK? BELT DESIGN ADVANTAGES AND DRAWBACKS CONCLUSSION

CONTENT OF PRESENTATIONCONTENT OF PRESENTATION

engine

CVT

planetary set

inertia

wheel

INTRODUCTION

CVT IS AN EMERGING AUTO MOTIVE TECHNOLOGY THAT

OFFERS A CONTINUUM OF GEAR RATIOS BETWEEN HIGH

AND LOW EXTREMS. TODAY CONTINUOUSLY VARIABLE

TRANSMISSION (CVT) HAVE LURED A GREAT DEAL OF

AUTOMOTIVEMANUFACTURERS AND CUSTOMERS.

low

overdrive

4000 rpm @80kph

HISTORY

CONTINUOUSLY VARIABLE TRANSMISSION(CVT)

DESIGN WAS DEVELOPED BY INVENTOR DR. JAN NAUDE.

CVT WAS FIRST PATENTED IN EUROPE IN 19TH CENTURY

THE FIRST PATENT FOR A CVT WAS FILED AT

THE END OF THE CENTURY.IT WAS DESIGNED AND BUILT

BY HUB VAN DOORNE.

low

NEED OF TRANSMISSIONNEED OF TRANSMISSION

THE TRANSMISSION TAKES THE POWER FROM THE ENGINE TO THE WHEEL,IN DOING SO ACTUALLY MAKES THE VEHICLE USABLE.

Allow the vehicle to start from rest, with the engine running continuously.

Let the vehicle stop by disconnecting the drive when appropriate.

Vary the speed ratio between the engine and wheels.

Allow this ratio to change when required.

Transmit the drive torque to the required wheels.

How does cvt works?How does cvt works? (CVT) offer a continuum of gear ratios between desired limits. Which allows the engine to operate more time in the optimum range given an appropriate control of the engine valve throttle opening (VTO) and transmission ratio. CVT operates by varying the working diameters of the two main pulleys in the transmission or by changing belt thickness

CVTCONTINUOUSLY VARIABLE TRANSMISSION CONTINUOUSLY VARIABLE TRANSMISSION

TYPES OF CVTTYPES OF CVT

PULLEY BASED CVT

ROLLER-BASED CVT

HYDROSTATIC CVT

INTERMESHING CONES

TOROIDAL

CVT DESIGN GOALSCVT DESIGN GOALS

Truly continuously variable

Transmit torque both forward and backward

Able to transmit high torque levels

Able to shift under load

Computer control not required

MECHANICAL LOSSES ARE LESS

CVT WORKING MODEL

CVT WORKING MODEL

Another version of the CVT the toroidal CVT system replaces the belts and pulleys with discs and power rollers.

Although such a system seems drastically different, all of the components are analogous to a belt-and-pulley system and lead to the same results a continuously variable transmission. One disc connects to the engine. This is equivalent to the driving pulley. Another disc connects to the drive shaft. This is equivalent to the driven pulley. Rollers, or wheels, located between the discs act like the belt, transmitting power from one disc to the other.

When the wheels are in contact with the driving disc near the center, they must contact the driven disc near the rim, resulting in a reduction in speed and an increase in torque (i.e., low gear). When the wheels touch the driving disc near the rim, they must contact the driven disc near the center, resulting in an increase in speed and a decrease in torque

Adaptable forAdaptable fortruckstrucks

Military vehicles Military vehicles

Heavy construction Heavy construction equipment equipment

Bicycle Bicycle

Motor cycles Motor cycles

Industrial machinery Industrial machinery

any type of motorany type of motor

IMPLEMENTED INIMPLEMENTED IN

Audi A4  TDI Audi A4  TDI Audi A6 2TDI Audi A6 2TDI Ford Escape Hybrid 2.3Ford Escape Hybrid 2.3Ford Focus CFord Focus CHonda Civic Hybrid Honda Civic Hybrid Honda HR-V 1.6 Honda HR-V 1.6 Honda Insight 1.0 Honda Insight 1.0 Nissan Murano 3.5 Nissan Murano 3.5 Nissan Primera 2.0 Nissan Primera 2.0 Nissan Serena 2.0 Nissan Serena 2.0 OPEL VETERAOPEL VETERASaturn VUE 2.2/3.5 Saturn VUE 2.2/3.5 Toyota Prius 1.5 4cyl Toyota Prius 1.5 4cyl

IMPLEMENTATION

CVTs have the potential to increase the overall vehicle CVTs have the potential to increase the overall vehicle efficiency and reduce the jerkefficiency and reduce the jerk CVTs can smoothly compensate for changing vehicle CVTs can smoothly compensate for changing vehicle speeds, allowing the engine speed to remain at its level speeds, allowing the engine speed to remain at its level of peak efficiency. of peak efficiency.

COST IS COMPARITIVELY HIGHERCOST IS COMPARITIVELY HIGHER

SIZE IS LARGER SIZE IS LARGER And And RELATIVELY COMPLEX MECHANISM RELATIVELY COMPLEX MECHANISM

ADVANTAGES & DRAWBACKS

IT IS ADVANTAGEOUS TO USE A CVT INSTEAD A IT IS ADVANTAGEOUS TO USE A CVT INSTEAD A MANUAL TRANSMISSION. THIS IS MAINLY BECAUSE MANUAL TRANSMISSION. THIS IS MAINLY BECAUSE THE ENGINE WILL OPERATE ALWAYS ON THE THE ENGINE WILL OPERATE ALWAYS ON THE OPTIMUM REGIMES AND THROTTLE-POSITIONS OPTIMUM REGIMES AND THROTTLE-POSITIONS ADAPTED TO THE VARYING ROAD CONDITIONS AND ADAPTED TO THE VARYING ROAD CONDITIONS AND POWER DEMANDS.POWER DEMANDS.

CONCLUSION

REFERENCES

Fischetti Mark . "No More Gears". “Popuplar Mechanics” by MC COSH http://auto.howstuffworks.com/cvt.html http://www.infovarna.com/cvt/index_uk.s.htmlhttp://www.histomobile.com/histomob/tech/2/83.htmlhttp://www.mitsubishimotors.com/corporate/about_us/technology/environment/e/cvt.htmlhttp://en.wikipedia.org/w/index.php?title=Special%3ABookSources&isbn=0831110848

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