Project

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

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 transmits the power from engine to the wheels through the shafts. It consists of 4 types mainly.

• Manual transmission
• Continous variabLe transmission
• Semi-automatic transmission
• Automatic transmission

A continuously variable transmission, or CVT, is a type of automatic transmission that provides more useable power, better fuel economy and a smoother driving experience than a traditional automatic transmission. The CVT is a system that makes it possible to vary step Less the transmission ratio without interruption of the torque flow. Therefore an infinite number of ratios {between a minimum and maximum value) are possible. It is an automatic, single speed, and gearless transmission that can shift through an infinite number of gear ratios. This ability to seamlessly shift through these different gears provides a number of benefits including extremely smooth shifts and exceptional fuel economy, A CVT draws top engine power from a small engine, which gives drivers quicker acceleration than standard automatic transmissions. Because of their greater ability to control the engine speed range, CVTs produce fewer emissions. CVTs are also Lighter weight than traditional automatic transmissions.

STUDY 1:-

By using simulink model of CVT consists of Signal builder, generic engine, motion sensors, vehicle transmission, vehicle body.tyres and solver configuration blocks etc., as shown in figure-1. The CVT subsystem includes Transmission block, input and output shaft inertia and motion sensors as shown in figure-2. The vehicle body subsystem includes vehicle body block, double drum brake and tyres . The initial engine speed is given as 2100 rpm, mechanical rotation for driven puLley and driver puLley as 0,8 & 0.7 respectively. The mass of the vehicle as 250kg and 2 axles which connects 4 wheel accordingly.

FIGURE-1 baja ATV model without dashboard

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FIGURE-2 CVT SYSTEM(SUBSYSTEM OF BAJA ATV MODEL):

FIGURE-3 VEHICLE BODY (SUBSYSTEM OF BAJA ATV MODEL):

STUDY 2:

'Baia ATV with dashboard' model which consists throttle meter and brake input in the dash board instead of giving input through signal builder. Rest of the blocks and subsystems are common in the above baja ATV model without dash board as shown in figure 2 & figure 3. The main concept of using dash board is study the result by varying the input of brake and throttle, which shows that the velocity and speed of the engine. The gear ratio is maintained as 2.3 for 5 secs and Linearly decreases to 1.8 and maintained constant for overall simulation as shown in figure 5. As the brake input varies from 0 - 03, the velocity and speed decreases accordingly. By increasing the throttle, the velocity and speed of the engine & shaft increases.

FIGURE:1 baja ATV model with dashboard:

FIGURE-2 CVT SYSTEM(SUBSYSTEM OF BAJA ATV MODEL):

FIGURE-3 VEHICLE BODY (SUBSYSTEM OF BAJA ATV MODEL):

STUDY 3:-

By using sirnulink model of CVT consists of step time, generic engine, motion sensors, vehicle transmission, vehicle body.tyres and solver configuration blacks etc., as shown in figure-7. The CVT subsystem includes look up table, Transmission block, input and output shaft inertia and motion sensors as shown in figure-8. The vehicle body subsystem includes vehicle body block, double drum brake and tyres as shown in figure-9. The initial engine speed is given as 2100 rpm, mechanical rotation for driven pulley and driver pulley as 0.8 & 0.7 respectively. The mass of the vehicle as 250kg and 2 axles which connects 4 wheel accordingly.
A lookup table is an array of data that maps input values to output values, thereby approximating a mathematical function. Given a set of input values, a Lookup operation retrieves the corresponding output values from the table. If the lookup table does not explicitly define the input values, simulink can estimate an output value using interpolation, extrapolation, or rounding, where:
• An interpolation is a process for estimating values that lie between known data points.
• An extrapolation is a process for estimating values that lie beyond the range of known data points.
• A rounding is a process for approximating a value by altering its digits according to a known rule.

FIGURE:1 baja ATV model using Lookup table without dashboard

FIGURE:2 CVT SYSTEM(SUBSYSTEM OF BAJA ATV MODEL)

FIGURE-3 VEHICLE BODY (SUBSYSTEM OF BAJA ATV MODEL)

FIGURE-4 Engine sensor

STUDY-4

Baja ATV with dashboard' model using Lookup table which consists throttLe meter and brake input in the dash board and indicated as constant black. Rest of the blocks and subsystems are common in the above baja ATV model without dash board as shown in figure 8 & figure 9. The main concept of using dash board is study the result by varying the input of brake and throttLe, which shows that the variation of velocity and speed of the engine. The gear ratio is given by Lookup table, simuLink get the input value from the lookup table and obtain the result according to the lookup table. As the brake input varies from 0 - 0.5, the veLocity and speed decreases accordingly which inturn the gear ratio also decreasing. By increasing the throttle, the veLocity and speed of the engine & shaft increases. The transmission as primary pulley and secondary pulley, in which the radius of primary puLley increses by compacting and the radius of secondary puLley decreases. As the gear ratio varies, the torque also varies. Gear ratio is directly proportional to the torque, which increases by increasing the gear ratio. At the max torque, the speed and veLocity is decreases.

FIGURE:1 baja ATV model using Lookup table with dashboard.

FIGURE:2 CVT SYSTEM(SUBSYSTEM OF BAJA ATV MODEL)

FIGURE-3 VEHICLE BODY (SUBSYSTEM OF BAJA ATV MODEL)

FIGURE-4 Engine sensor

RESULTS:

Study1- variation of velocity and shaft speed

In this figure, the brake is maintained as constant and increase in throttle which shows increase in velocity. The flow of fuel is ncreses
when the throttle increases from 0.3 to 1, thus the power in the engine increases. The torque reaches approximately 7N-m at L8 gear ratio,
which defines that gear ratio is directly proportional to the torque. By this gear ratio, the speed & velocity can achieve maximum.

Study2-variation of velocity and shaft speed

In the above figure, the velocity of the vehicle is maintained as constant for constant throttle value as 0.3 and varying by increasing the
value of throttle which increases the velocity of vehicle. By increasing the brake input, the velocity of the vehicle decreasing accordingly

study-3 variation of velocity and shaft speed

In the above figure, the brake is maintained as constant and increase in throttle which shows increase in velocity. The flow of fuel is ncreses
when the throttle increases from 0.3 to 1, thus the power in the engine increases. The torque reaches approximately 7N-m at L8 gear ratio,
which defines that gear ratio is directly proportional to the torque. By this gear ratio, the speed & velocity can achieve maximum. The gear
ratio is assigned in lookup table and given as input to the simulink which reads every input value and obtain the result according to the input.

study-4 variation of velocity and shaft speed

In the above figure, the velocity of the vehicle is maintained as constant for constant throttle value as 0.3 and varying by increasing the
value of throttle which increases the velocity of vehicle. By increasing the brake input, the velocity of the vehicle decreasing accordingly
which shown in figure18. 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.