Project
SIMULATION OF ALL TERRAIN VEHICLES
AIM:
To prepare technical report of simulation BAJ All terrain vehicle (ATV) under different conditions.
Objectives
Carry out a system-level simulation of all terrain vehicles and prepare a technical report explaining the model properties comments on result
ALL TERRAIN VEHICLE:
An all-terrain vehicles(ATV) is defines as a motorized off highway vehicle design to travel on four low pressure or non- pneumatic tires. Having a seat designed to be straddled by the operator and handle bars for steering controls.
STUDY-1
CASE-1
SIMULINK MODEL FOR BAJA ATV WITH CVT:
Major comonents in the model :
Continuously Variable transmission system(CVT):
It is better to have more gears in transmission, since it can optimize engine speed in a variety of driving condition. That mean low gears can provide better acceleration while higher gear can maximize the fuel e economy. CVT differ from traditional automatic transmissions in that thy don’t have gear that provide “steps” between low and high speed operations. Instead, the majority of them work via a pair of a variable diameter, cone shaped pulley connected by a steel or composite belt. The halves of each pulleys are aligned with the pointed ends of cones touching these form V shaped groove in which the connecting belt rides. One side of pulley I fixed and the other side is movable actuated by the hydraulic cylinder the cylinder can increase or decrease the space between two sides of pulley. This allows the belt to ride lower or higher long the walls of the pulley, depending on the driving condition, There by changing the “gear” ratio.
CVT BLOCK:
VARIABLE TRANSMISSION RATIO:
Represented a variable ratio gear box such as implemented by mechanical belt CVT electric or hydraulic transmissions. The physical signal inputs defines the ratio of input to output angular shaft velocities.
Connection B(base) and F(follower) are mechanical rotational conserving ports. Specify the relation between base and follower rotation direction with the output shaft rotates parameters.
ENGINE:
Representation system level model of spark-ignition and diesel ignition suitable for use at initial stage model when only the basic parameters are available. Optional idle speed and red line controllers are included. The throttle input signal lies between zero and one specifies the torque demanded from the engine as a fraction of maximum possible torque.
Connection F and B are mechanical rotational conserving ports associated with the engine crank shaft and engine block respectively. connection P an FC are physical signal output port through which engine power and fuel consumption rate are reported.
INPUT SIGNAL
CVT GEAR RATIO INPUT:
Torque vs engine speed input
VEHICLE BODY:
OUTPUT FOR CASE1:
VEHICLE SPEED:
It is clear from the graph that the vehicle attains the maximum speed(V=55 km/hr) at full throttle = 1 after 35 seconds and the remains constant the brake input value is zero hence it has no effect on velocity.
CVT SHAFT RPM
These graph shows the variation of angular velocities of input and output shafts of the variable gear transmission system. These values differ with respect to the gear ratio.
STUDY#1:
CASE-2
SIMULINK MODEL RFOR BAJA ATV WITH SCT USING DASHBOARD:
In this model we have dashboard which contains knob to control the input. A knob is provides to control both parameters in real time for the user.
OUTPUT for CASE-2
Vehicle speed
It can be observed from the graph that the velocity increases from 0-50 when throttle value is 0.5 and brake is 0. Once the braking value is increase 0.1-0.5 the velocity of the vehicle decreases to 0 at constant throttle value. This explains direct relation of vehicle velocity with respect to throttle and brake inputs.
CVT Shaft RPM:
STUDY-2
CASE 1:
SIMULINK MODEL OF BAJA ATV WITH CVT USING LOOKUP TABLE :
CVT BLOCK:
This only difference between this model and first model is that in this model, the gear ration input to CVT is provided using a lookup table. The vehicle velocity and shaft RPM outputs are same as before.
CVT Gear Ratio
LOOKUP TABLE VISUALISATION:
OUTPUT for CASE 1:
VEHICLE SPEED
CVT SHAFT RPM:
Both result are same that of the first case : SIMULINK MODEL FOR BAJA ATV WITH CVT since the input parameters are same
STUDY-2
CASE-2
SIMULINK MODEL FOR BAJA ATV WITH CVT USING LOOKUP TABLE AND DASHBOARD:
In this model a dashboard is used to control the inputs ‘throttle’ and ‘ brake’ with knob
OUTPUT FOR CASE-2
VEHICLE SPEED:
This graph similar to that of CVT dashboard case the variation in vehicle velocity can be observed with change in throttle and brake inputs. With increase in braking value the speed of vehicle decreases on the other hands increasing the throttle value leads to increase the velocity.
CVT shaft RPM
This graph indicates the variation in RPM primary and secondary shaft with respect to input parameters.
CONCLUSION:
Thus we have successfully analysed 4 different models of BAJA ATV with CVT and recorded the inputs: (Vehicle velocity and CVT shaft rpm) with respect to variations in input throttle and brake