SYSTEM LEVEL SIMULATION ON AN ATV USING SIMULINK

Aim:

To perform a system level simulation on an ATV and analyse the result.

Theory:

ALL TERRAIN VEHICLE(ATV):

An ATV(All Terrain Vehicle) is a vehicle that can run on all terrains.They are specially designed for the very purpose.Theses vehicles are mostly used for off road conditions and adventure sports.They have specially designed Suspension System and types that can suit every terrain.They are generally a single rider vehicles except in some cases.ATV's are usually not desgined for high performances,instead for stability and adventure.

Continous Variable Tranmission(CVT):

A Continously Variable Transmission(CVT) is an automatic tranmission system that can change seamlessly through a continous range of effective gear ratio.It is also called as Shiftless transmission,Seamless tranmisson and in case in bikes twist and go.A CVT doed not require a clutch but in some cases a centrifugal clutch is added to facilitate the neutral stance.A belt drive is used offering an efficiency of 88%.

The Model under study is a BAJA All Terrain Vehicle(ATV) model with Continous Variable Tranmission(CVT).

Report:

This is the proposed model of an All Terrain Vehicle(ATV) designed for BAJA with a Continous Variable Transmission(CVT).There are 3 subsystems in the model for Enigne,CVT and for the Vehicle body.Outputs from different blocks are collected and are plotted and the performances are analysed.

Powertrain:

A Generic Engine is used which is the most simple type of Spark Ignition Engine in Simulink and can be categorised into Petrol and Diesel Variants.A subsystem is present which has the sensors to capture the movement of the engine.The engine is parametrised on Tabulated Torque data

The engine is parametrised on Tabulated Torque data and the default parameters are used for the simulation which could be varied according to the users data.A basic model is used here with minimal parameters.

Transmission:

A CVT is used for transmission,which is degined using a variable gear inside a subsystem and the gear ratio is changed using the torque output that is achieved in a closed loop system.

Vehicle Body:

The vehicle body is designed with the basic blocks of brakes and wheels,no parameters are changed and are kept to default that can be changes according to the user.Basic blocks of wheels are used and are conected to the variable torque provided by the CVT.The output velocity is obtained and the results.

The brake and throttle initial conditions are given using the signal builders.

The output from the velocity is again fed to the CVT to vary the gear ratio which gives the torque data.

Outputs:

SPEED VS TORQUE:

It can be observed that at the begining the RPm starts from 1500 and the torque obtained is high.As the RPM increases.The torque decreses after some time as the rated maximum RPM of a BAJA ATV is 3840.

The other observed relations are as shown:

VELOCITY VS TIME:

This curve is velocity curve shows the behaviour of the velocity with the throttling and braking beahviour with a gear ratio of 4.

CVT shaft speed:

The shaft speed of a primary and secondary CVT can be obeserved here with respect to time.

Results:

Therefore a system level simulation on an ATV has been done and the results have been analysed.