Project

Aim:

To prepare a technical report of Simulation of BAJA All-Terrain Vehicle (ATV) under different conditions

Objectives:

Carry out a system-level simulation of an all-terrain vehicle and prepare a technical report explaining the model properties & comments on the results.

ALL-TERRAIN VEHICLE:

An all-terrain vehicle (ATV) is defined as a motorized off-highway. the vehicle is 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.

 SECTION A 

 CASE STUDY-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 transmission since it can optimize engine speed in a variety of driving conditions. That means low gears can provide better acceleration while higher gears can maximize fuel economy. CVTs differ from traditional automatic transmissions in that they don't have gears that provide "steps" between low- and high-speed operations. Instead, the majority of them work via a pair of variable diameter, cone-shaped pulleys connected by a steel or composite belt. The halves of each pulley are aligned with the pointed ends of the cones touching. These form a V-shaped groove in which the connecting belt rides. 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 transmissions. The physical signal input r defines the ratio of input to output angular shaft velocities.

Connections B (base) and 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 the initial stages of modelling when only the basic parameters are available. Optional idle speed and red line are included. 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. Connections F and B are mechanical rotational conserving ports associated with the engine crankshaft and engine block. Connections P and FC are physical signal output ports through which engine power and fuel consumption rate are reported

INPUT SIGNAL 

A signal builder is used to building the signal for brack and throttle 

CVT Gear ratio 

Torque Vs Speed curve 

VEHICLE BODY

 RESULT FOR CASE-STUDY 1 

it is clear from the graph that if a vehicle attains its maximum speed (V=55km/hr) at full throttle 1 after =35 seconds and then remain constant the brack input value is zero hence it has no effect on velocity    

CVT SHAFT RPM

this graph shows the variation in the velocity in input and output shafts of the variable gear transmission system this value differs concerning the gear ratio.

 SECTION A 

 CASE-STUDY 2: 

 SIMULINK MODEL FOR BAJA ATV WITH CVT USING DASHBOARD:- 

 

In this model, we have a dashboard that contains knobs to control the inputs. In this case, the inputs- Throttle & Brake' are not provided using the signal builder. A knob is provided to control both the parameters in real-time for the user.

 RESULT FOR CASE-STUDY 2 

VEHICLE SPEED :

It can be observed from the graph that the velocity of the vehicle increases drastically from 0 to 50kmph when throttle value is 0.5 & brake input is O. Once the braking value increases from 0.1 to 0.5, the velocity of the vehicle decreases to O at constant throttle value. This explains the direct relation of vehicle velocity with respect to throttle and brake inputs.

 SECTION B 

 CASE STUDY-1 

 SIMULINK MODEL FOR BAJA ATV WITH CVT USING LOOKUP TABLE :- 

 

 

The only difference between this model and the first model is that in this model gear ratio input to CVT is provided using a lookup table. The vehicle velocity and vehicle rpm is the same as the first model 

 RESULT FOR CASE-STUDY 1 

VEHICLE SPEED 

CVT SHAFT SPEED 

Both results are the same as the input parameter is the same 

 SECTION B 

 CASE STUDY-2 

 SIMULINK MODEL FOR BAJA ATV WITH CVT USING LOOKUP TABLE AND DASHBOARD:- 

in the above model we the new thing is that this model provides us with the control brake input and throttle input 

 RESULT FOR CASE-STUDY 2 

VEHICLE SPEED 

 

This graph is similar to the CVT dashboard case study the variation in vehicle velocity can be observed with the change in brake input and throttle input when we are increases the break input the speed of the vehicle is decrease on another case we can see that when we increase the throttle input the vehicle velocity also increase.

This graph indicates the variation in rpm of primary and secondary shafts with respect to input parameters.

CONCLUSION:

Thus we have successfully examined 4 various models of BAJA ATV WITH CVT and recorded the outputs:- (Vehicle velocity & CVT shaft rpm) with respect to variations in input throttle and brake.