Project

The system depicts an All Terrain Vehicle(ATV) with Continuously Variable Transmission(CVT).The five basic building blocks of the system are :Vehicle Body,Suspension,Tyre,Engine and CVT.In between the blocks Engine and CVT Variable Gear Ratio block is there.The CVT block essentially comprises of a Primary Pulley,a Secondary Pulley,a Variator and a Belt.The system also includes an Input Block and a Controller Block.The Input Block generates a Brake Input and a Throttle Input.The Throttle Input is fed to the Speed Controller.The Engine Speed is sensed by a Speed Sensor.The difference between the Set Speed and Measured Speed results in an Error Signal that drives the Speed Controller which in turn modulates the CVT.CVT Ratio is the ratio between the diameters of Primary Pulley and Secondary Pulley.There may be two possibilities : CVT Ratio greater than 1 or CVT Ratio less than 1.When it is less than 1 Primary Pulley rpm is more than Secondary Pulley rpm.This signifies speed reduction.On the other hand when CVT Ratio is more than 1 Secondary Pulley rpm is higher than Primary Pulley rpm.This signifies overdrive.Vehicle Speed and Displacement are outputs from the system.After running of simulation a plot of Torque against Vehicle Speed is obtained.Simulation Data Inspector is used for extraction of data points.

Some critical observations from the simulation are as under.

1.Maximum vehicle velocity is same irrespective of mass of it.

2.When Gear Ratio was 2 not enough torque was generated to drive the vehicle.

3.When Gear Ratio was 4 there was tendency of overdrive since maximum speed(3840) was already attained.

4.When Gear Ratio was 8 simulation time was 26 seconds.

5.CVT ratio range was randomly chosen from 0.4 to 3.0.

Moreover, Secondary Pully velocity very closely matches with the vehicle velocity as rear wheel of the vehicle is connected to Secondary Pulley.Depending on CVT output vehicle can move in either Forward or in Backward direction.