Project

AIM:

The main aim is to study the case study of BAJA ATV model vehicle and need to analysis the results.

THEORY:

ALL TERRAIN VEHICLE (ATV):

An all-terrain vehicle (ATV), also known as a light utility vehicle (LUV) a quad bike, or simply a quad, as defined by the American National Standards Institute (ANSI); is a vehicle that travels on low-pressure tires, with a seat that is straddled by the operator, along with handlebars for steering control. As the name implies, it is designed to handle a wider variety of terrain than most other vehicles. Although it is a street-legal vehicle in some countries, it is not street-legal within most states, territories and provinces of Australia, the United States or Canada. By the current ANSI definition, ATVs are intended for use by a single operator, although some companies have developed ATVs intended for use by the operator and one passenger. These ATVs are referred to as tandem ATVs.

CONTINOUS VARIABLE TRANSMISSION (CVT):

A continuously variable transmission (CVT) is an automatic transmission that can change seamlessly through a continuous range of gear ratios. This contrasts with other transmissions that provide a limited number of gear ratios in fixed steps. The flexibility of a CVT with suitable control may allow the engine to operate at a constant RPM while the vehicle moves at varying speeds. CVTs are used in automobiles, tractors, motor scooters, snowmobiles, bicycles and earthmoving equipment. The most common type of CVT uses two pulleys connected by a belt or chain; however, several other designs have also been used at times.

BLOCKS USED IN THE MODELS:

1. SIGNAL BUILDER:Signal buider block is used to give signal inputs to brake input and throttle inputs.
2. ENGINE SENSOR:Engine sensorcontaing ideal mechanical rotational sensor that converts an across variable measured between two mechanical rotational into a control signal propotional to angular velocity.engine sensor is connected to generic engine.
3. GENERIC ENGINE:Generic engine is a system level of model of spark ignition and diesel engines usable at intial stage of modelling when only the basi modelling are available.
4. SIMPLE GEAR: Engine is connected to CVT with simple gear ratio.
5. SCOPE:To view the graph.
6. DISPLAY:To view the calculated values.
7. VARIABLE GEAR RATIO:To vary the speed according to the gear ratio.
8. VECHICLE BODY:To represent the BAJA vehicle.
9. ROTATIONAL MOTION SENSOR:To sense the rotational motion from the engine and give output as RPM.
10. TIRE:Tire for transportation of vehicle.
11. STEP:Step block is used to increase or decrease an input value for a defined time interval.
12. PS-CONSTANT:To generate the physical signals.

BRAKE AND THROTTLE INPUT SIGNALS:

CVT RATIO:

CASE STUDIES:

STUDY-1:

BAJA ATV WITH CVT:

CVT SHAFT SPEED PLOT:

IN CVT variator primary pulley goes inward and secondary pulley goes outward which leads to over ride.primary pulley radius decreases and secondary pulley radius increases.

ENGINE SPEED:

Engine speed decreases at the begining because increase in gear ratio which increaes the torque.

TORQUE VS SPEED CURVE:

ATV WITH CVT USING DASH BOARD:

TORQUE VS SPEED:

ENGINE SPEED:

ATV WITH CVT USING LOOKUP TABLE:

LOOKUP TABLE VISUALISATION:

TORQUE VS SPEED:

CONCLUSION:

System level of simulation of baja all terrain vehicle is done and results were plotted.