Project

To prepare a technical report of Simulation of BAJA All-Terrain Vehicle (ATV) under different conditions

OBJECTIVE:

• SIMULINK MODEL FOR BAJA ATV WITH CVT:
• SIMULINK MODEL FOR BAJA ATV WITH CVT USING DASHBOARD
• SIMULINK MODEL FOR BAJA ATV WITH CVT USING LOOKUP TABLE
• SIMULINK MODEL FOR BAJA ATV WITH CVT USING LOOKUP TABLE & DASHBOARD

ALL-TERRAIN VEHICLE:

An all-terrain vehicle (ATV) is defined as a motorized off-highway vehicle designed to travel on four low-pressure or non-pneumatic tires, with a seat designed to be straddled by the operator and handlebars for steering control.

INTRODUCTION: Transmission transmits the power from the engine to the wheels through the shafts.

It consists of 4 types mainly,

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

• SIMULINK MODEL FOR BAJA ATV WITH CVT:

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 stepless the transmission ratio without interrupting 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.

CVT SUBSYSTEM

VEHICLE BODY SUBSYSTEM

ENGINE SENSOR

TORQUE-SPEED CURVE

Break and throttle input

• SIMULINK MODEL FOR BAJA ATV WITH CVT USING DASHBOARD

In this model, we have a dashboard which contains knobs to control the inputs. In this case, the inputs- ‘Throttle’ & ‘Brake’ are not provided using the signal builder. A knob is provided to control both parameters in real-time for the user.

• SIMULINK MODEL FOR BAJA ATV WITH CVT USING LOOKUP TABLE

By using Simulink model of CVT consists of step time, generic engine, motion sensors, vehicle transmission, vehicle body,tyres and solver configuration blocks 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 wheels 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.

• SIMULINK MODEL FOR BAJA ATV WITH CVT USING LOOKUP TABLE & DASHBOARD

The above figure shows 'Baja ATV with dashboard' model using lookup table which consists throttle meter and brake input in the dash board and indicated as constant block. 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.