Project
Aim: - To prepare a report on baja all-terrain atv model.
Theory: -
Here we can see that the BAJA electric have different component like engine, CVT, vehicle body. we are giving break input as zero and throttle input is from 0.3 to 120 seconds. If we see the output then we can observe that as we increase the throttle ,the velocity of the vehicle increases at certain time and reaching to a maximum velocity.
The above graph shows typical behaviour of the BAJA engine. In this model we are creating data sheet to the model,and from the graph the data sheet is created with the help of grabit.
Contineously variable transmission(CVT)
It consist of primary pulley variator, secondary pulley variator and belt so the variator which is connected to the primary pulley goes outward,the variator of the secondary pulley will move inward such that the radius of the secondary pulley will be more than the primary pulley,and that will lead to speed reduction. On the other hand when variator of the primary pulley move inward the variator of the secondary pulley will move outward and leads to overdrive.
Now if we move to simscape block we can see that we have input shaft inertia, outout shaft inertia which represent primary and secondary pulley and to specify the gear ratio .we have variable gear ratio block.
Now to connect the engine and CVT we need some speed reduction so for that we are using simle gear ratio. If we see the torque vs speed graph then we can see ,green simulation has stopped and the gear ratio=2 we don't have enough ratio to accelerate the vehicle.
Velocity Body
In the vehicle body we can specify car mass number of axes and different parameters. If we consider vehicle velocity with different masses they will attain same maximum velocity but initially velocity of vehicle which has least mass is higher as compare to the heavy mass.
If we see the behaviour of the primary and secondary rpm and the vehicle velocity by changing the CVT ratio. As we can see that when the CVT ration is less than "1" i.e before 26 seconds, the rpm of the primary is greater then the secondary and once it cross that i.e when it is less than "1" the secondary rpm is more than the primary.
Conclusion: -
These models show how to build an ATV with CVT which is mostly used in BAJA competitions. Simscape and Simscape Driveline have been used to complete the system. The engine data used in the model which shows the Engine Speed (RPM) Vs Torque curve.