Project
AIM:-
To prepare a technical report of simulation of BAJA-Terrain Vehical (ATV) Under different condition.
OBJECTIVE:-
Carry out a system level simulation of an all-terrain vehical and prepare a technical report explaining the model properties & comments on the results.
ALL TERRAIN VEHICLE:-
An all terrain vehical (ATV) is define as a motorized off-highway vehicle designed to travel on four low-pressure or non-pneumatic tires, having a seat designed to be straddled by the operator and handlebars for steering control.
STUDY 1:-
CASE 1:-
Simulink Model For BAJA ATV with CVT:-
Major Components in the model :-
Continuously Variable Transmission drive (CVT):-
It is better to have more gears in a transmission, since it can optimize engine speed in a variety of driving conditions. That mean low gear can provide better accelaration while higher gear can maximum fuel economy. CVTs differ from traditional automatic transmission in that they dont have gear that provide 'steps' between low-and high-speed operations. instead,the majority of them work via a pair of variable-daimeter,cone-shaped pulleys coonected by a steel or composite belt.the halve of each pully are aligned with the pointed ends of the cones touching. these form a V-shaped groove in which the connected belt ride. One side of the pulley is fixed,and the other side is movable, actuated by a hydraulic cylinder.The cylinder can increase or decrease the amount of space between the two sides of the pulley.This allows the belt to ride lower or higher along the walls of the pulley, depending on driving conditions, thereby changing the 'gear' ratio.
CVT Block:
VARIABLE TRANSMISSION RATIO :-
Represents a variable ratio gearbox such as implemented by mechanical belt CVT,electric,or hydraulic transmission. The physical signal input r defines the ratio of input to output angular shaft velocities.
Connections B (base) & F (follower) are mechanical rotational conserving ports. Specify the relation between base and follower rotation directions with the output shaft rotates parameter.
ENGINE :
Represents a system level model of spark ignition and diesel engines suitable for use at initial stages of modelling when only the basic parameters are available. Optional idle speed and red line controlles are include. the throttle input signal T lies between zero and one and specifies the torque demanded from the engine as a fraction of the maximum possible torque.
Connection F & B are mechanical rotational conserving ports associated with the engine crankshaft and engine block respectively.Connections P & FC are physical signal output ports through which engine power and fuel consumption rate are reported.
Input Signal :-
A Signal builder is used to create signals for brake & throttle.
CVT Gear Ratio Input :-
Torque vs Engine Speed Input :-
Vehical Body :-
OUTPUT FOR CASE 1 :-
VEHICLE SPEED :-
It is clear from the graph that the vehical attains its maximum speed (V=55km/hr) at full throttle=1 after 30 seconds and then remain constant. The brake input value is zero , hence it has no effect on velocity.
CVT SHAFT RPM :-
These graphs shows the variation in angular velocities of input and output shafts of the variable gear transmission system. These values differ with respect to gear ratio.
STUDY 1:-
CASE 2:-
Simulink Model For BAJA ATV with CVT using DASHBOARD :-
In this model we have a dashboard which contains knobs to control the input. In this case, the inputs-'Throttle' & 'Brake' are not provided using signal builder . A knob is provided to control both the parameter in real time for the user.
OUTPUT for CASE 2 :-
Vehicle Speed :-
It can be observed from the graph that the velocity of the vehicle increases drastically from 0 to 50 kmph when throttle value is 0.5 & brake input is 0. Once the braking value incrases from 0.1 to 0.5, the velocity of the vehicle decreases tob0 at constant throttle value. this explains the direct relation of vehical velocity with respect to throttle & brake inputs.
CVT SHAFT RPM :-
STUDY 2:-
CASE 1:-
Simulink Model For BAJA ATV with CVT using LOOKUP TABLE :-
CVT Block :-
The only difference between this model & the first model is that in this model, the gear ratio input to CVT is provided using a lookup table. the vehicle velocity and shaft rpm output are same as before.
CVT Gear Ratio :-
Lookup Table Visualisation :-
OUTPUT for CASE 1:-
Vehicle Speed:-
CVT Shaft RPM :-
Both result are same as that of the first case :- Simulink Model for BAJA ATV with CVT since the input parameter are same.
STUDY 2:-
CASE 2:-
Simulink Model for BAJA ATV with CVT using LOOKUP TABLE & Dashboard :-
In this model a dashboard is used to control the inputs-'Throttle' & 'Brake' with knobs.
OUTPUT OF CASE 2:-
VEHICLE SPEED :-
This graph is similar to that of cvt dashboard case.The variation in vehicle velocity can be observed with change in throttle and brack input with increase in braking value, the speed of vehicle decreases. On the other hand, increasing the throttle leads to increased vehicle velocity.
CVT SHAFT RPM :-
This graph indicates the variation in rpm of primary and secondary shafts with respect to input parameters.
CONCLUSION :-
Thus we have successfully analysed 4 different models of BAJA ATV WITH CVT and recorded the outputs:-(Vehicle velocity & CVT shaft rpm) with respect to variations in input trottle and brake.