Project

Technical Report

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

keywords: CVT, dashboard,baja ATV, lookup table

software: simulink,matlab

objective:

1. study the baja ATV model without dashboard
2. study the baja ATV model with dashboard
3. study the baja ATV model using lookup table without dashboard
4. study the baja ATV model using lookup table with dashboard

Introduction:

transmission which transmit the power from engine to wheels through the shaft its consist 4 type.

• manual transmission
• continous variable transmission
• semi-automatic transmission
• automatic transmission

CVT is a type of automatic transmission that provides more useable power better fuel economy and smoother driving experiance than the traditional automatic transmission.the CVT system that makes it possible to an infinite number of ratio between max. and min. speed value are possible.CVT has greater ability to control the engine speed range.CVT produce fewer emission CVT are also ligheter weight than traditional automatic transmission system.

study 1:

by using simulink model of CVT consist of signal builder generic engine motion sensor vehicle transmission vehicle body tyre and solver blocks fig.1 shown that the CVT subsystem include transmission block input and output shaft inertia and motion sensor.fig 2 shown that vehicle body subsystem include vehicle body block double drum brake and tyre shown in fig 3.the initial range of speed as 2100 rpm.mechanical rotation for driven and driver pully as 0.8 and 0.7 resp.mass of body 250kgand 2 axle connects 4 wheels accordingly.

BAJA ATV Model:

CVT subsystem:

vehicle body sub-system:

The signal builder is used to as input for brake throttle ,gear ratio.brake input is used as 0 for overall simulation.throttle input is given as 0.5 for over all simulation.the throttle valve is mainly to control the flow or amt of fuel into the engine.if the throttle value increasses the flow of fuel increasses to generic engine.so power of engine also increasses.CVT gear ratio is maintained 3.7 foe first few sec.and then exponentially decreasses upto 0.8 and then maintained constant for overall simulation time.its show in below fig.

STUDY 2:

BAJA ATV with dashboard model:

the below fig.shows that BAJA ATV with dashboard model which is consist throttle meter and brake input in a dashboard instead of giving input through signal builder.rest of block and subsystem is same as first study.the main concept of using dashboard is study the result by varying the input of brake and throttle.which show that the velocity and speed of the engine.the CVT gear ratio is maintained 3.7 foe first few sec.and then exponentially decreasses upto 0.8 and then maintained constant for overall simulation time.the velocity and speed decreasses by increasing the throttle the velocity and speed of the engine and shaft increases.

STUDY 3:

BAJA ATV model using look up chart:

by using the simulink model of CVT consist of CVT of stop time.generic engine motion sensor vehicle transmission vehicle body and solver.that the CVT subsystem include transmission block input and output shaft inertia and motion sensor.fig shown that vehicle body subsystem include vehicle body block double drum brake and tyre shown iin fig the initial range of speed as 2100 rpm.mechanical rotation for driven and driver pully as 0.8 and 0.7 resp.mass of body 250kgand 2 axle connects 4 wheels accordingly.

a lookup table is an array of data that mass input value to output value thereby approximating a mathematical function given a set of input value a lookup operation retrives the corresponding output value from the tabel.

• an interpolation is a process for estimating value that lie between known data points
• an extrapolation is a process for estimating value that lie beyond the range of known data points
• a rounding a process for approximating a value by altering its digits according to a known rule.

CVT subsystem:

Vehicle body subsystem:

The brake input and throttle input a given by step time which depends on the run time and value according by using lookup table for gear ratio which takes as input to the CVT and works according to the input gera ratio and obtained the output.

Lookup table visualization:

study 4:

BAJA ATV model with dashboard using look up chart:

the below fig.shows that BAJA ATV with dashboard using look up table model which is consist throttle meter and brake input in a dashboard instead of giving input through signal builder.rest of block and subsystem is same as first study.the main concept of using dashboard is study the result by varying the input of brake and throttle.which show that the velocity and speed of the engine.the gear ratio is given by lookup table simulonk get the input value from 0-0.5 the velocity and speed decreases according which interm the gear ratio also decreasing. as the gear ratio varies the torque also varies gear ratio is directly propotional to the torque which increasing by inceasing the gear ratio at the max torque the speed and velocity is decreasing.

output:

study 1:variation of velocity and shaft speed.

in above fig. the brake is maintained as constant and increases in throttle which shows increase in velocity.the flow of fuel is increses when the throttle from 0.3 to 1 thus the power in the engine increases the torque reaches approximatly 7 n-m at 1.8 gear ratio which defines that gear ratio is directly propotional to the torque by this gear ratio the speed and velocity can achive max.

in the above fig. the primarly shaft reaches high speed and secondarly shaft as low rotational speed bcoz the radius of the primarly shaft as more then the secondarly shaft.the speed is directly propotional to the radius of the shaft as the radius increases the speed of the shaft also increases.

study 2:variation of velocity and shaft speed.

in the above fig. velocity is maintaned as constant for constant throttle value as 1 and the varying by decreasing the value of throttle decreasing the velocity of vehicle.by increasing the brake input the velocity of vehicle decreasing.

in the above fig. the primarly shaft reaches high speed and secondarly shaft as low rotational speed bcoz the radius of the primarly shaft as more then the secondarly shaft.the speed is directly propotional to the radius of the shaft as the radius increases the speed of the shaft also increases.the primary shaft speed increases by increases throttle and decreasing by increasing brake input value.

STUDY3:variation of velocity and shaft speed.

in above fig. the brake is maintained as constant and increases in throttle which shows increase in velocity.the flow of fuel is increses when the throttle from 0.3 to 1 thus the power in the engine increases the torque reaches approximatly 7 n-m at 1.8 gear ratio which defines that gear ratio is directly propotional to the torque by this gear ratio the speed and velocity can achive max.

the primary shaft speed increases by increases throttle and decreasing by increasing brake input value.the primarly shaft reaches high speed and secondarly shaft as low rotational speed bcoz the radius of the primarly shaft as more then the secondarly shaft.the speed is directly propotional to the radius of the shaft as the radius increases the speed of the shaft also increases.

STUDY4: variation of velocity and shaft speed.

in the anbove fig. the velocity of the vehicle is maintained as constant for constant throttle valueas 0.3 and varying by increasing the value of throttle which increasses the velocity of vehicle by increasing the brake input the velocity of the vehicle decreasing according which shown in fig. by using lookup table it works as closed loop by recording the velocity value and we can get at any particular value of gear ratio which is beyond the range or any random value within the range by using extrapolation and interpolation by lookup table.

the primary shaft speed increases by increases throttle and decreasing by increasing brake input value.the primarly shaft reaches high speed and secondarly shaft as low rotational speed bcoz the radius of the primarly shaft as more then the secondarly shaft.the speed is directly propotional to the radius of the shaft as the radius increases the speed of the shaft also increases.