Project
AIM: To study the system level simulation of an all terrain vehicle.
KEYWORDS: CVT, lookup table, Dashboard, baja ATV
sOFTWARE: Matlab, Simulink
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
stepless 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 aliso weight than traditional automatic transmissions.
STUDY 1
By using simulink model of CVI consists of signal builder, generic
engine, motion sensors, venicle 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 as shown in
figure-3. 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-3
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 0.3 for20 secs and increases to 1 for overall simulatuion. The
throttle valve is mainly to control the flow or amount of fuel into the
engine, if the throttle value increases the flow of fuel increases to the IC
engine which inturn increases the power 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 (4-5).
Figure-6
The above figure shows Baja 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
n 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 throtle, which shows that the velocity
and speed of the engine. The gear ratio is maintained as 2.3 for 5 secs
and ineary decreases to 18 and maintained constant for overall
simulation as shown in figure 5. As the brake input varies from 0-0.5,
the velocity and speed decreases accordingly. By increasing the
throttle, the velocity and speed of the engine & shaft increases.
STUDY 3
By using Simulink model of CVT consists of step time, generic engine,
motion sensors, vehicle transmission, vehicle bodytyres 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
igure-s. 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 tehicle as 250kg and 2 axes which connects 4 wheel
accordingly.
A lookup table is an array of data that maps input values to output
values, thereby approximatinga mathematical function. Given a set of
input values, a lookup operation retrieves the corresponding output
values from the table. Iif 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-6
The above figure shows Baja 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
n 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 throtle, which shows that the velocity
and speed of the engine. The gear ratio is maintained as 2.3 for 5 secs
and ineary decreases to 18 and maintained constant for overall
simulation as shown in figure 5. As the brake input varies from 0-0.5,
the velocity and speed decreases accordingly. By increasing the
throttle, the velocity and speed of the engine & shaft increases.
STUDY 3
By using Simulink model of CVT consists of step time, generic engine,
motion sensors, vehicle transmission, vehicle bodytyres 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
igure-s. 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 tehicle as 250kg and 2 axes which connects 4 wheel
accordingly.
A lookup table is an array of data that maps input values to output
values, thereby approximatinga mathematical function. Given a set of
input values, a lookup operation retrieves the corresponding output
values from the table. Iif 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 -12
In the above figure, 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.
Figure-13
In the above figure, the primary shaft reaches high speed and
secondary shaft as low rotational speed because the radius of the
primary shaft as more than the secondary shaft, the speed is directly
proportional to the radius of the shaft. As the radius increases the speed
of the shaft also increases.
Study 2:-Variation of velocity & Shaft speed
Figure-14
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
figurel4.
Figure- 15
In the above figure, the primary shaft speed increases by increasing
throttle and decreasing by increasing brake input value, which defines
that the throttle can flow more amount of fuel which increases the
power of the engine and similar to the secondary shaft. The radius of
the primary shaft as more than the secondary shaft the speed is
directly proportional to the radius of the shaft. As the radius increases
the speed of the shaft also increases.
Study 3:-Variation of velocity & Shaft speed
Figure-16
In the above figure, 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 18 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.
Figure-17
In the above figure, the primary shaft speed increases by increasing
throttle and decreasing by increasing brake input value, which deines
that the throttle can flow more amount of fuel which increases the
power of the engine and similar to the secondary shaft. The radius of
the primary shaft as more than the secondary shaft, the speed is
directly proportional to the radius of the shaft. As the radius increases
the speed of the shaft also increases.
Study 4:-Variation of velocity & Shaft speed
Figure-18
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
figurel8. 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.
Figure-19
In the above figure, the primary shaft speed increases by increasing
throttle and decreasing by increasing brake input value, which defines
that the throttle can flow more amount of fuel which increases the
power of the engine and similar to the secondary shaft. The radius of
the primary shaft as more than the secondary shaft, the speed is
directly proportional to the radius of the shaft. As the radius increases
the speed of the shaft also increases. The throttle value and brake input
value can be varying in dashboard, so we can get any particular value
CONCLUSION:
1. As the throttle increases, the velocity also increases which inturn the
power in the engine also increases
figure 21:-
figure 22:-
Figure - 23
In the above figure, the velocity is varying wrt the gear ratio. For the high
gear ratio, the torque is more which decrease the velocity. By changing
to high gear, the gear ratio become less paralelly the torque also less
which can get high velocity.
4. With help of lookup table, we can vary any input value and also get
the output value by using interpolation and extrapolation method which
the simulink can solve.