Challenge

Project

DDevansh Tiwari17 Mar 2022

Aim:To prepare a detailed technical report on simulation of BAJA All-terrain vehicle (ATV) under different condition

Objective: To Carry out a system-level simulation of an all-terrain vehicle.

All terrain vehicle

An all terrain vehicle (ATV) is defined as a motorized off highway vehicle designed to travel on 4 low pressure or non pneumatic tyres,having a seat & handle to control the steering.

Case-1

Simulink Model for BAJA ATV with CVT

Major blocks in the model

1. Continuous variable transmission drive

More Gears in a transmission ,more optimization of speed of engine n various terrain & condition.The low gears provide better acceleration while the higher gears increases the fuel economy

A CVT does not have transmission as traditional drives have. It does has gears that provides steps between low & higher speed opeartion .Instead they have pair of variable diameter cone shaped pulleys connected by V-Belt.One side of the pulley is fixed while other is movable actuated by hydraulic cylinder. The cylinder can increase or decrease the amount of space between the two sides of pulleys. This allows the belt to ride lower or higher along the walls of pulley "changing the gear ratio". Below is the CVT block

2. Variable transmission ratio

Represents a variable ratio gearbox as implemented by mechanical belt CVT,electric or hydraulic transmission.

The physical signal input 'r' represents the ratio of input to ouptut angular shaft velocities.

Connections B (base) & F (follower) are mechanical rotational conserving ports.

3. Engine

Here the engine present a system level model of spark ignition.Optional ideal speed & red line controllers are included.The throttle input signal T lies between zero & one & specifies the torque demanded from the engine as a fraction of the maximum possible torque.

Connections F & B are mechanical rotational conserving ports associated with the engine crankshaft & engine block.Connections P & FC are physical signal output ports through which engine power & fuel consumption rates are reported.

Input Signal

CVT Gear ratio input

Vehicle Body

Output for case 1

Vehicle speed

it is clear from the above graph that vehicle attains a speed of 55KM/Hr at full throttle =1 after 30 sec & remains constant thereafter.

CVT Shaft RPM

These shafts shows the variation in angular velocities of input & output shafts of the variable gear transmission.These values differ wrt. gear ratio.

Case 2

Here we have dashboard which have knobs to control the input throttle and brake.Its a kind of real time simulation for user.

Output for case 2

Vehicle speed

Vehicle speed increases to 0 to 50 KM/Hr when throttle value is 0.5 % brake input value is 0. As brake input value is increased from 0 to 0.5 the speed reduces to 0 km/hr.

CVT shaft RPM