Week 3 : Calculating vehicle and trailer values using Drive Cycles in Matlab (DHEV)

Q1) Consider a vehicle and trailer having the following parameters:

Consider the scenario of flat ground, no headwind and no trailer. Analyze the following cycles:
a. UDDS
b. HWFET

For each cycle, compute the following:
1. Average positive power in kW
2. Maximum positive power in kW
3. Maximum negative power in kW
4. Positive energy requirement in kJ
5. Energy requirement with 100% regen (no power limitation, 100% efficient)
6. Energy requirement with regen when power is limited to 10, 20, 30, 45, 60 kW and 80% efficient.

Tabulate the above results. Plot the total power requirement at the wheel for each cycle. Plot the energy requirement as a function of regen power. Use Matlab for calculations and plotting.

Comment on the results, comparing the differences and outlining certain observations. Comment on how the requirements are different for both the cycles and which road load components and hence which vehicle parameter will affect the power and energy requirements the most. Also comment what would the overall vehicle power requirements be to complete each cycle.

Note: For calculating rolling radius, assume rolling radius to be 97% of the tire calculated radius, due to tire compression. For case with trailer, only consider the aerodynamic drag of the trailer, as it has much
larger projected area and higher drag coefficient

Q1. UDDS :

Program :

close all
clear 
clc
% Given
M = 2400 ;
g = 9.81 ;
theta = 0 ;
V_wind = 0 ;
C_d = 0.35 ;
A_f = 2.4 ;
rho_a = 1.225 ;
C_r = 0.013 ;
r = 0.38 ;
P_lim = [10 20 30 45 60] ;

% Process 
data = xlsread ('UDDS.xlsx');
test_time = data (:,1);
traget_speed = data(:,2);
V = traget_speed ;
t = test_time ;
F_rr = (C_r*M*g*cos(theta)) ;
for i = 1:length (V)-1
    F_ad(i) = (0.5*rho_a*A_f*C_d*V(i).^2) ;
    F_a(i) = (M*(V(i+1)-V(i))) ;
    Force (i) = F_rr + F_ad(i) + F_a(i) ;
    Power(i) = Force(i).* V(i);
    Energy(i) = Power(i) * t(i);
end
    P_aver = mean (Power) ;
    P_pos =Power (Power > 0) ;
    P_neg =Power (Power < 0) ;
    E_pos = Energy (Energy > 0) ;
    E_neg = Energy (Energy < 0) ;
figure (1)
power = [0 Power];
plot (t,power,'LineWidth',3,'Color','B')
figure (2)
energy = [0 Energy];
plot (t,energy,'LineWidth',3,'Color','G')

Explanation :

• Data give are taken from table and UDDS data is also collected.
• Then program is created using for loop and plotting grapths.
• During Process the formulas are also used.
• F_ad, F_a, Force, Power, Energy are the values are to be calculated.
• Where the P_aver, P_pos, P_neg, E_pos, E_neg are also calculated
• plottinig the power and Enegy using time in x axis.

Values :

• P_aver = 1.4714e+04 kW
• P_pos :

• P_neg :

• E_pos :

• E_neg :

Graphs :

1. Power Vs Time :

2. Energy Vs Time :

Q2. HWFET :

Program :

close all
clear 
clc
% Given
M = 2400 ;
g = 9.81 ;
theta = 0 ;
V_wind = 0 ;
C_d = 0.35 ;
A_f = 2.4 ;
rho_a = 1.225 ;
C_r = 0.013 ;
r = 0.38 ;
P_lim = [10 20 30 45 60] ;

% Process 
data = xlsread ('HWYCOL.xlsx');
test_time = data(:,1);
traget_speed = data(:,2);
V = traget_speed ;
t = test_time  ;
F_rr = (C_r*M*g*cos(theta)) ;
for i = 1:length (data)-1
    F_ad(i) = (0.5*rho_a*A_f*C_d*V(i).^2) ;
    F_a(i) = (M*(V(i+1)-V(i))) ;
    Force (i) = F_rr + F_ad(i) + F_a(i) ;
    Power(i) = Force(i).* V(i);
    Energy(i) = Power(i) * t(i);
end
    P_aver = mean (Power) ;
    P_pos =Power (Power > 0) ;
    P_neg =Power (Power < 0) ;
    E_pos = Energy (Energy > 0) ;
    E_neg = Energy (Energy < 0) ;
figure (1)
power = [0 Power];
plot (t,power,'LineWidth',3,'Color','B')
figure (2)
energy = [0 Energy];
plot (t,energy,'LineWidth',3,'Color','G')

Explanation :

• Data give are taken from table and HWFET data is also collected.
• Then program is created using for loop and plotting grapths.
• During Process the formulas are also used.
• F_ad, F_a, Force, Power, Energy are the values are to be calculated.
• Where the P_aver, P_pos, P_neg, E_pos, E_neg are also calculated
• plottinig the power and Enegy using time in x axis.

Values :

• P_aver = 7.8527e+04 kW
• P_pos :

• P_neg :

• E_pos :

• E_neg :

Graphs :

1. Power Vs Time :

2. Energy Vs Time :