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synopsis on continuous variable transmission



Continuous Variable Transmission 


In continuously variable transmission (CVT) infinite number of effective gear ratios changes from maximum to minimum values. The difference between other mechanical transmissions and continuously variable transmission (CVT) is few different distinct gear ratios to be selected. Better fuel economy can be achieved by enabling the engine to run at most effective revolutions per minute in continuously variable transmission (CVT) than other mechanical transmission systems.

A continuously Variable transmission (CVT) is a transmission which can gradually shift to any effective gear ratios between a set upper and lower limit. The almost infinite variability of a CVT allows the engine to maintain a constant speed while the vehicle increases in velocity. This can result in better vehicle performance if the CVT is shifted such that the engine is held at the RPM that it runs most efficiently at and/or produces the most power. Because there are no steps between effective gear ratios, CV T’s operate smoothly with no sudden jerks commonly experienced in manual transmission. Since drivers expect a car to jerk or the engine sound to change as they press the accelerator pedal further, it is very confusing for them when the car smoothly accelerates without the engine revving faster. Drivers have unfortunately perceived this as the car lacking power which is causing a marketing problem for the transmissions
Mainly the CVT has primary and secondary clutches which are connected by belt in which the Primary clutch is connected to the Ac motor and Secondary Clutch connected to the gear box and the power is transmitted from Primary clutch to the Secondary clutch by belt.

Primary and Secondary clutches are made of pulley’s. To have the required performance of the vehicle the speed of the engine has to be reduced in the CVT, this variation in the speed reduction can be achieved by changing the contact diameters of the belt on pulleys. In normal pulleys the diameter cannot be changed so to have change in the contact diameter between belt and pulley, the pulley used are different from the conventional pulleys.

Material Required:

  • V-Belt Pulley’s

  • Ac motor

  • Bearings

  • Nut Bolts

  • Shafts

  • Belt

  • Metallic Stand


For power transmission instead of gears we are using Two pulley’s connected by a belt. We are using AC motors on one side to drive the primary section of the Project. Primary Section includes Pulley with bearings connected to AC motor. Ac motors turn on the Primary pulley. The other one is connected to the rest of transmission to the wheels. The magic of CVT is that the size of the pulleys can change from small to large, and infinite sizes in between. So to start off with, the AC motor’s pulley will be small and the other one large, In this case the speed at the Secondary side of the project will low. As the Diameter of the Primary is about 20 mm and the diameter of the Secondary is about 42 mm which is very large. So the speed will be low at the secondary side of the CVT. Once the we change the diameter of the primary pulley, As we start increasing the diameter and take make it up to extreme level suppose 42 mm. In this case the diameter the secondary reduces about 20 mm. Now the speed of the Secondary pulley increases. Hence it starts delivering high amount of power transmission and RPM( revolution per minute).


Continuously variable transmissions (cvt) are praised for being able to deliver a smooth driving experience and improve fuel efficiency, with no fixed gear ratios. CVT is most suitable and easy way to transfer the power from one point to another. It is widely used in industries for power transmission.


  1. Money saving

  2. Time Saving

  3. Efficiency increasing

  4. More output in less time


After all the testing we are successful in representing our idea of the project in practical way. The project on which we are working is working with very ease and efficient way. We are able to transfer the variable power transmission from one mechanism to another.