Project

AIM: To study the system level simulation of an all terrain vechicle

Software Used:Matlab,Simulink

Objective:

1)To study the baja ATV model without dashboard

2)To study the baja ATV model using lookup table without dashboard

3)To study the baja ATV model with dashboard

4)To study the baja ATV model with dashboard

Introduction: Apart from all the transmission systems, the continous variable transmission(CVT) system was greatly prefered in baja all terrain vechicle.A continous variable transmission or CVT is a type of automatic transmission that provides more useful power,improves fuel efficiency and enhances smoother driving experience than the normal traditional transmssion systems.It is an automatic,single speed and gearless transmission that can shift through a infinite gear ratios.It provides extremely smooth shifting of gears and good fuel economy.CVTs have the greater ability to control the different speed range also fewer emissions.

Study(1):

In the basic simulink model of the CVT consists of a signal builder,generic engine,motion sensor,solver configuration blocks etc.Also there was CVT subsystem which was included by transmission block,input and output shaft inertia and motion sensors.In the vechicle body subsystem it was included with vechicle body block,double drum brake and tyres.We can know purpose and specifications of all the blocks used in its block parameters.The scope gives the variation between the different entries used.

Study(2) Baja ATV with dashboard model

In this model it consists of throttle input and brake input in its dashboard.Instead of giving the brake and throttle inputs in the signal builder it can be given in the dashboard itself.All the blocks and subsystems used in the above system are same except the dasboard.The main use of dashboard is to know the result by varying the inputs of brake and throttle in its meters.We can observe the variations in speed and velocity of the engine by varying the brake and throttle.We can observe from the simulation that by increasing the throttle, speed ,velocity of engine and shaft increases.

Study(3) Model using lookup table without dashboard

The simulink model of this type consists all the blocks that are in the figure.The CVT subsystem includes lookup table and all the other blocks are same as used in previous studies.It is also same in the vechicle body subsystem as in other studies.

The lookup table is an array of data that maps inputs and output.Given a ste of input values a lookup operation retrives the corresponding the values of the table. If the lookup table does not explicitily define the input values then the simulink can estimate the output values by interpolation,extrapolation and rounding methods.

Interpolation is the process for estimating the values in the given data points

Extrapolation is the process of estimating the values that lie beyond the range of input data

Rounding is the process of approximating the value by the known value in the input set.

By using lookup table for gear ratio which takes as the input to the CVT and works according to the input gear ratio and obtained the output.It was very effective which can avoid the unusual torque produced at certain speeds and very easy to acheive greater velocity and engine speed.The simulink gets the inputs from the lookup table and obtain the input values accordingly to the gear ratios,it can be easily seen in the graph.

Study(4) Model with dashboard using lookup table

This model of the simulink consists of dashboard in which it has brake meter and throttle meter.All the rest of the blocks used are same in the above model and also same for the sub system blocks.The main use of the dashboard is to study the results by varying the inputs of brake and throttle in its meters directly from the dashboard without giving in the signal builder.The simulink gets the input from the lookup table and obtain the results according to the lookup table.As we know that by increasing the throttle, the speed and velocity of the shaft and the engine increases.As the gear ratios varies the torque also varies.Torque is directly proportional to the gear ratio,which increases by increasing the gear ratio.At the maximum torque conditions the speed and velocity decreases which can be seen in the graph.

The different types of plot were plotted to know the variations in the velocity and shaft speed at different throttle ranges.