CONTINUOUSLY VARIABLE TRANSMISSION (CVT) BMS COLLEGE OF ENGINEERING CONTINUOUSLY VARIABLE TRANSMISSION (CVT) NARAYAN .H.M SEMESTER -8 1BM07ME060 MECHANICAL ENGG.DEPT.

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

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. engine planetary set inertia CVT wheel

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. 4000 rpm @80kph low overdrive

NEED OF TRANSMISSION low 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. low

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

CONTINUOUSLY VARIABLE TRANSMISSION CVT

TYPES OF CVT PULLEY BASED CVT ROLLER-BASED CVT HYDROSTATIC CVT INTERMESHING CONES TOROIDAL

CVT 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

IMPLEMENTATION IMPLEMENTED IN Adaptable for trucks Military vehicles Audi A4  TDI Audi A6 2TDI Ford Escape Hybrid 2.3 Ford Focus C Honda Civic Hybrid  Honda HR-V 1.6 Honda Insight 1.0 Nissan Murano 3.5 Nissan Primera 2.0 Nissan Serena 2.0 OPEL VETERA Saturn VUE 2.2/3.5 Toyota Prius 1.5 4cyl Adaptable for trucks Military vehicles Heavy construction equipment Bicycle Motor cycles Industrial machinery any type of motor

ADVANTAGES & DRAWBACKS CVTs have the potential to increase the overall vehicle efficiency and reduce the jerk CVTs can smoothly compensate for changing vehicle speeds, allowing the engine speed to remain at its level of peak efficiency. COST IS COMPARITIVELY HIGHER SIZE IS LARGER And RELATIVELY COMPLEX MECHANISM

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

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.html http://www.histomobile.com/histomob/tech/2/83.html http://www.mitsubishimotors.com/corporate/about_us/technology/environment/e/cvt.html http://en.wikipedia.org/w/index.php?title=Special%3ABookSources&isbn=0831110848

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