WOT Condition

Title : To calculate Wide Open Throttle.

Objective:

1. To calculate the ratio of hill climbing power required by fully loaded tata ultra truck to the half loaded one.
2. To Calculate how much can be the minimum length of the flyover, considering the minimum height at the summit should be 5.5 meters.
3. Prepare a new drive cycle excel file for the model and also include a hill-climbing angle to it.
4. Model the WOT (Wide Open Throttle) response of GM EV1 car. Compare it with the official figures of the performance of a real vehicle. Prepare a table showing variation in acceleration time with 5% change in vehicle parameters.

Solution:

1. Ratio of hill climbing power required by fully loaded tata ultra truck to the half loaded one.

Thus Ratio of Hill Power for fully and half loaded is 1.19.

2. To Calculate how much can be the minimum length of the flyover, considering the minimum height at the summit should be 5.5 meters.

Solution:

As we have Gradeability of Tata ultra = 33%

As the Gradeability of Tata ultra is 33% then the Angle of elevation is near about 18 degree

We know that

Sin(`theta`)= Opp.side/Hyp

Then,

Theta = 18

Opp. side = minimum height = 5.5

Sin(18)= 5.5/hypo(minimum length of the flyover)

therefore , Minimum length of flyover =17.51 meter.

3. Prepare a new drive cycle excel file for the model and also include a hill-climbing angle to it.

Solution :

Prepare excel sheet with Time and veleocity column

Time = 0- 200sec

Velocity = 0- 100kmph

Then , Import the data file in MatLab using IMPORT DATA tab

While importing sheet , select column vector and Range = A3:B202

Check workspace after importing sheet.

We have successfully imported excel sheet in Matlab.

Then , use command Drive_cycle1 = [Time Velocitykmph]

Name of Sheet = Drive_cycle1.

this is use to convert import data into matric format.

Now ,We have Driver_Glider simulation file.

Then Place imported data file in Source block parameter.

Run the data in Simulink we will get the Result in workspace.

We can give different hill climb angle by changing value in this parameter.

4. Model the WOT (Wide Open Throttle) response of GM EV1 car. Compare it with the official figures of the performance of a real vehicle. Prepare a table showing variation in acceleration time with 5% change in vehicle parameters.

Solution:

Assume input parameters as follows.

Drag coefficient cd = 0.19;
rolling_resistance=0.0048;
mass=1000;
Gear ratio=11;
radius =0.30;
Tmax=140;
wc=733;
v=19.8;
a=1.8;
Gear efficiency =0.95;

We know equation for Acceleration Time

(G/r).T=(`drag coefficient`.m.g)+(0.625.A.Cd.v^2)+(m+(I(g^2/gear eff. r^2))(dv/dt)

Now put all values in this equation.

Condition 1 : Consider original parameter

i.e V(n+1) = Vn+dt(3.0-0.00032Vn^2)

CODE !

clc
clear all
close all

%Wide open throttle response for GM EV 1
%Input Data
Cd = 0.19;
rolling_resistance=0.0048;
m=1000;
G=11;
r=0.30;
Tmax=140;
wc=733;
v=19.8;
a=1.8;
eff=0.95;
t=linspace(0,30,301);
vel=zeros(1,301);
vel1=0;
dt=0.10;
for n=1:300
    if vel(n)<19.8
        vel(n+1)=vel(n)+dt*(3.08-(0.000137*(vel(n)^2)));
    else if vel(n)>=19.8
            vel(n+1)=vel(n)+dt*((62.1/vel(n))-0.046-(0.000137*(vel(n)^2)));
        end
        if vel(n)>36
            vel(n+1)=vel(n);
        end
    end
end

vel=vel.*3.6;
figure(1)
plot(t,vel);
%axis([0 33 0 100]);
xlabel('Time sec');
ylabel('velocity kph');
title('WOT of GM EV 1');
grid on

We get plot

Condition 2 : Take 5% change in parameters.

Mass1=1050;
Gear ratio 1=11;
a=1.9;

i.e V(n+1)= Vn+dt[(59.14/Vn)-0.044-0.00032Vn^2]

CODE 2

%Wide open throttle response for GM EV 1  varied by 5%
%Input Data
m1=1050;
G1=11;
a=1.9;
% vel1=vel.*3.6;
for n=1:300
    if vel1(n)<19.8
        vel1(n+1)= vel1(n)+dt*(2.95-(0.00013*(vel1(n)^2)));
    else if vel1(n)>19.8
            vel1(n+1)= vel1(n)+dt*((59.14/vel1(n))-0.046-(0.00013*(vel1(n)^2)));
        end;
        if vel1(n)>35.8
            vel1(n+1)=vel1(n);
        end
    end
end
vel1=vel1.*3.6;
figure(2)
plot(t,vel1);
%axis([0 33 0 100]);
xlabel('Time sec');
ylabel('velocity kph');
title('WOT of GM EV 1 varied by 5%');
grid on

We get plot 2

Lets compare 2 plots with variation in Acceleration time Original Parameter and 5% varied parameter

figure(3)
plot(t,vel);
hold on
plot(t,vel1);
title ('WOT OF GM EV 1')
legend ('Original Parameter','5% varied parameter')
xlabel('Time sec');
ylabel('velocity kph');
grid on

we get final plot output

Conclusion:

• Thus from above we can say that increase in vehicle parameter leads in increase of acceleration Time.
• Minimum length of flyover =17.51 meter.
• Thus Ratio of Hill Power for fully and half loaded is 1.19.