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

A continuously variable transmission (CVT) is an automatic transmission that can change seamlessly through a continuous range of gear ratios. This contrasts with other transmissions that provide a limited number of gear ratios in fixed steps. The flexibility of a CVT with suitable control may allow the engine to operate at a constant RPM while the vehicle moves at varying speeds.

CVTs are used in automobiles, tractors, motor scooters, snowmobiles, bicycles and earthmoving equipment.

The most common type of CVT uses two pulleys connected by a belt or chain; however, several other designs have also been used at times.

STUDY-1

in image-1 simulink model of CVT consists of Signal builder, generic engine, motion sensors, vehicle transmission, vehicle body,tyres and solver configurationblocks etc...

image-2 (sub system) consists of transmission block,shafts,moions sensors etc...

in the image-3 vehicle body subsystem includes vehicle body block, double drum brake and tyres etc..

The initial engine speed is given as 1670 rpm, The mass of the vehicle as 250kg and 2 axles which connects to all wheels

The signal builder is used as input for brake, throttle and gear ratio. Brake input is maintained as 0 for overall simulation. The throttle input is given as 0.5 for 20 secs as shown in image 4

STUDY-2

in image-5 shows 'Baja ATV with dashboard' which consists throttle meter and brake input in the dash board

except dash board blocks and subsystems are same in the previous baja ATV model without dash board as shown in image-2&3. the advantage of dash board is we can visualize the output values,the break input maintained as 0 and throttle input is given as 0.5 for 20 secs

STUDY 3:

The CVT subsystem includes look up table-(image-6), Transmission block,dashboard-(image-5), input and output shaft inertia and motion sensors as shown in the

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.

inlookup table visualization we can see that in higher gear ratios higher the torque and less velocity,lower gear ratios higher velocities is the output-(image-6).

In the image-7 the brake is maintained as constant and increase in throttle which shows increase in velocity. The flow of fuel is increses when the throttle
increases from 0.3 to 1, thus the power in the engine increases. The torque reaches approximately 7N-m at 1.8 gear ratio, which defines that gear ratio is directly
proportional to the torque. By this gear ratio, the speed & velocity can achieve maximum.

in image-8 we can see that at 1500 rpm tere is rise in torque,and after reachin a particular point there is no much rise in engine torque wrt to engine rpm,and there is a noticable torque deduction at in between of 3500-4000 engine rpms.