Challenge

Project 2

SSravan Kumar S.L.V11 May 2022

Description:
As discussed in Lecture 11, Project 2 deals with the development of a forward energy-based fuel consumption model of a P1 hybrid vehicle. This model is based on the conventional vehicle model from Project 1.

The main goal of this project is to understand the functionality of a P1 hybrid and be able to model it.

Honda Insight motor and battery are considered for this project. Data is taken from ADVISOR data base developed by NREL, USA. Data provided in the project files.

“Project2_InitFile.m” is a Matlab script used to load all the variables required for running the Simulink model and for post-processing. The drive cycle selection is also done here. Before running the Simulink vehicle model, run this initialization script.

Task:

The task of this project is to quantify the improvement in fuel economy numbers for the hybrid vehicle (kmpl), compared to the conventional vehicle, on the urban cycle (UDDS) and highway cycle (HWFET). Also, to analyze and understand the vehicle operating points in terms of engine and motor speed, torque, transmission speeds, pedal positions, gear, distance traveled, battery voltage, current, SoC etc.

To do that, the following steps need to be followed:

1) Load the Project2 folder as the Current Folder in Matlab.
2) Run the “Project2_InitFile.m” Matlab script.
3) Copy the Conventional vehicle Simulink model created for Project 1 in this folder. Figure 1: P1 Hybrid ArchitectureHybrid Drives Development
4) Modify this model into a hybrid vehicle model. The lecture presentations can be used as reference. Battery and Supervisory controller models developed in the assignments can be reused.
5) Add additional ‘To Workspace’ blocks for transferring the desired Simulink vehicle data into the Matlab workspace.
6) Simulate the hybrid model on the desired drive cycles.
7) Write a project report that contains the following:
a. Tabulate the fuel economy numbers (kmpl) for UDDS and HWFET cycle. Compare these numbers with the baseline numbers for conventional vehicle model from Project 1.
b. Plot the time trace for engine, transmission input, transmission output and wheel speed on one plot.
c. Plot engine torque, engine power, fuel rate and fuel consumption using subplots.
d. Plot accelerator and brake pedal, gear command, vehicle desired and actual speed, vehicle distance using subplots.
e. Plot the engine operating points on the engine fuel map.
f. Plot motor speed, torque, motor input power using subplots.
g. Plot pack voltage, current and SoC using subplots.
h. Plot the motor operating points on the motor input power map, with the motor max motoring and generating torque curves.
i. Write down appropriate brief comments on each of these plots, describing the vehicle behavior throughout the drive cycle.
j. Generate the plots for both drive cycles.

solution:

step1:

M = 1500;       % Vehicle weight [kg]
Cr = 0.015;     % Rolling resistance coefficient
Rw = 0.35;      % Rolling radius [m]
Cd = 0.33;      % Drag coefficient
Af = 2;         % Frontal area [m2]
rhoa = 1.225;   % Air density [kg/m3]
Vwind = 0;      % Wind velocity [kmph]
g = 9.81;       % Gravitational acceleration [m/s2]
theta = 0;      % Slope [deg]
myu_road_tire = 1; % Coefficient of friction between tire - road interface

%% Powertrain Parameters 
FDR = 3.73;                         % Final Drive Ratio / Diff Ratio
DiffEff = 0.99;                     % Differential efficiency (assumed independent of operating conditions)

NumGear = 4;                        % Number of gears in transmission
TransGear = [1:NumGear];            % Transmission Gears
TransRatio = [3.06, 1.62, 1, 0.7];  % Corresponding Transmission ratios
TransEff = 0.90;                    % Transmission efficiency (assumed independent of operating conditions)

TC_SR = [0, .5, .6, .7, .8, .87, .92, .94, .96, .97, 1];   % Torque Converter Speed Ratio (Matlab default) -> TurbSpd/PumpSpd  
TC_TR = [2.232, 1.5462, 1.4058, 1.2746, 1.1528, 1.0732, 1.0192, 1, 1, 1, 1];   % Torque Converter Torque Ratio (Matlab default) -> TurbTrq/PumpTrq
TC_Cf = 1e-4 * [.72558, .66322, .63463, .59042, .51331, .4144, .29287, .22444, .12186, .04386, 0]; % Torque Converter Capacity Factor (Matlab default) -> PumpTrq/PumpSpd^2 [Nm/rpm^2]

load Vehicle_Data/Engine_data_1_9L_Saturn_95kW
load Vehicle_Data/Trans_Shift_map
load Vehicle_Data/EM_Honda_Insight_10kW
load Vehicle_Data/ESS_NiMH6


ESS_init_soc = 0.8;
ESS_soc_max = 0.9;
ESS_soc_min = 0.6;


%% Driver Parameters
Kp = 10;                    % P gain for driver PI model
Ki = 1;                     % I gain for driver PI model
Drive_Cycle_Select = 2;     % Drive cycle selection

% Drive cycle values in m/s

if Drive_Cycle_Select == 1
    load DriveCycles/UDDS;
    
elseif Drive_Cycle_Select == 2
    load DriveCycles/HWFET;
    
elseif Drive_Cycle_Select == 3
    load DriveCycles/FTP;
    
elseif Drive_Cycle_Select == 4
    load DriveCycles/US06;
    
elseif Drive_Cycle_Select == 5
    load DriveCycles/NEDC;
    
elseif Drive_Cycle_Select == 6
    load DriveCycles/WLTP;
 
end

time_end = cyc_time(end);
vel_end = cyc_vel(end);

step 2: Hybrid Vehcile model

Figure 1. Vehicle Model.

Driver Block:

Figure 2. Driver Block.

In this driver block drive cycle lookup table, PI control and saturation blocks are used. The main purpose of the PI Control block is to achieve the required speed given by the drive cycle. The maximum acceleration is limited to 100 and -100 using saturation blocks.

Controller: In this controller block, state-space blocks are used to attain the required modes of operation. For this block, acceleration, Brake, Velocity, SOC, Clutchlockup, and Engspd are inputs. Also, from this block, the outputs are Mode, Eng_On, Eng_thr, and Em_thr. These outputs are connected to the corresponding blocks which are shown in figure 3. 5 different control signals are generated for the power train block and signals are EngTrqReq, Gearcmd, cluctch lock up, EMtrqreq, Brktrqreq.

Figure 4. Controller block diagram.

Power train: As this is a hybrid drive, Electric_motor, and Engine is used. Along with that transmission, differential, wheels, and vehicle dynamics are used to get the required propulsion power.

Figure 5. Power train block set.

Time = out.tout;
Acc_Pdl = out.Acc_Pdl;          % Accelerator pedal [%]
Brk_Pdl = out.Brk_Pdl;          % Brake pedal [%]
Gear_Cmd = out.Gear_Cmd;        % Transmission gear
Trans_In_Spd = out.Trans_In_Spd*30/pi;  % Transmission input speed [rpm]
Trans_Out_Spd = out.Trans_Out_Spd*30/pi;% Transmission output speed [rpm]
Eng_Trq = out.Eng_Trq;          % Engine brake torque [Nm]
Eng_Spd = out.Eng_Spd*30/pi;    % Engine speed [rpm]
Eng_Fuel_Consump = out.Eng_Fuel_Consumption;    % Engine fuel consumption [g]
Veh_Dist = out.Veh_Dist/1000;   % Distance traveled by vehicle [km]
Veh_Spd = out.Veh_Spd*18/5;     % Vehicle speed [kmph]
Eng_Fuel_Rate=out.Eng_Fuel_Rate;%Engine fuel rate%

%% Data Analysis
Eng_Pwr = Eng_Spd.*pi/30.*Eng_Trq/1000;   % Engine brake power [kW]
rho_petrol = 0.7197;                    % Density of petrol [kg/L]
kmpl = Veh_Dist(end)/(Eng_Fuel_Consump(end)/1000/rho_petrol);    % Fuel economy [kmpl] 


%% Plotting vehicle characteristics time trace
figure(1)
subplot(3,1,1)
hold on
grid on
plot(Time, Eng_Spd, 'linewidth', 1, 'Color', 'black');
ylabel('Eng_Spd')
xlim([0, Time(end)]);
legend('Eng_Spd');
subplot(3,1,2)
hold on
grid on
plot(Time, Trans_In_Spd, 'linewidth', 1, 'Color', 'black');
plot(Time, Trans_Out_Spd, 'linewidth', 1, 'Color', 'red');
ylabel('Speed [rpm]')
xlim([0, Time(end)]);
ylim([0, 6000]);
legend('Trans Input','Trans Output');
subplot(3,1,3)
hold on
grid on
plot(Time, Veh_Spd, 'linewidth', 1, 'Color', 'black');
xlim([0, Time(end)]);
xlabel('Time [s]');
ylabel('Vehicle_Speed');
legend('Vehicle_Spd');

figure(2)
subplot(3,1,1)
hold on
grid on
plot(Time, Eng_Trq, 'linewidth', 1, 'Color', 'red');
ylabel('Engine Torque [Nm]')
xlim([0, Time(end)]);
legend('Eng Trq');
subplot(3,1,2)
hold on
grid on
plot(Time, Eng_Pwr, 'linewidth', 1, 'Color', 'red');
ylabel('Engine Power [KW]')
xlim([0, Time(end)]);
legend('Power');
subplot(3,1,3)
hold on
grid on
plot(Time,Eng_Fuel_Consump , 'linewidth', 1, 'Color', 'green');
xlim([0, Time(end)]);
xlabel('Time [s]');
ylabel('Fuel Consumption');

figure(3)
subplot(3,1,1)
hold on
grid on
plot(Time, Eng_Trq, 'linewidth', 1, 'Color', 'red');
ylabel('Engine Torque [Nm]')
xlim([0, Time(end)]);
legend('Eng Trq');
subplot(3,1,2)
hold on
grid on
plot(Time, Eng_Pwr, 'linewidth', 1, 'Color', 'red');
ylabel('Engine Power [KW]')
xlim([0, Time(end)]);
legend('Power');
subplot(3,1,3)
hold on
grid on
plot(Time,Eng_Fuel_Rate , 'linewidth', 1, 'Color', 'black');
xlim([0, Time(end)]);
xlabel('Time [s]');
ylabel('Eng_Fuel_Rate');

figure(4)
subplot(3,1,1)
hold on
grid on
plot(Time, Acc_Pdl, 'linewidth', 1, 'Color', 'red');
plot(Time, Brk_Pdl, 'linewidth', 1, 'Color', 'blue');
ylabel('Pedal')
xlim([0, Time(end)]);
legend('Acc_Pdl','Brk_pdl');
subplot(3,1,2)
hold on
grid on
plot(Time, Gear_Cmd, 'linewidth', 1, 'Color', 'red');
ylabel('Gear')
xlim([0, Time(end)]);
legend('Gear_Cmd');
subplot(3,1,3)
hold on
grid on
plot(Time,Veh_Spd, 'linewidth', 1, 'Color', 'black');
xlim([0, Time(end)]);
xlabel('Time [s]');
ylabel('Veh_Spd');
legend('Veh_Spd');

figure(5)
subplot(3,1,1)
hold on
grid on
plot(Time,out.EM_Trq,'linewidth',1,'color','red');
ylabel('Motor Torque[Nm]');
xlim([0,Time(end)]);
legend('Motor Trq');
subplot(3,1,2)
hold on
grid on
plot(Time,out.ElecPwr,'linewidth',1,'color','red');
ylabel('motor power (kw)');
xlim([0,Time(end)]);
legend('Motor power');
subplot(3,1,3)
hold on
grid on
plot(Time, out.EM_Spd, 'linewidth',1,'color','green');
xlim([0,Time(end)]);
xlabel('Time(s)');
ylabel('motor speed');

figure(6)
subplot(3,1,1)
hold on
grid on
plot(Time, out.term_volt,'linewidth',1,'color','green');
ylabel('Voltage(V)');
xlim([0,Time(end)]);
legend('voltage');
subplot(3,1,2)
hold on
grid on
plot(Time,out.soc,'linewidth',1,'color','red');
ylabel('SOC');
xlim([0,Time(end)]);
legend('SOC %')
subplot(3,1,3)
hold on
grid on
plot(Time,out.pack_Current,'linewidth',1,'color','blue');
ylabel('SOC');
xlim([0,Time(end)]);
xlabel('Time(s)');
ylabel('pack_current');




%% Plotting engine operating points on engine fuel map
figure('Name','Engine Operating Points');
hold on
grid on
title('Engine Operating Points','fontsize',12);
p1=plot(Eng_map_spd*30/pi,Eng_max_trq,'linewidth',2,'color','r');
p2=line([Eng_map_spd(end)*30/pi Eng_map_spd(end)*30/pi],[0 Eng_max_trq(end)]);
set(p2,'linewidth',1,'linestyle','--','color','k');
p3=line([Eng_map_spd(1)*30/pi Eng_map_spd(1)*30/pi],[0 Eng_max_trq(1)]);
set(p3,'linewidth',1,'linestyle','--','color','k');
[c,h] = contour(Eng_map_spd'*30/pi,Eng_map_trq,Eng_fuel_map');
clabel(c,h);
xlabel('Engine Speed [rpm]');
ylabel('Engine Torque [Nm]');
title('Engine Fuel Consumption Map [g/s]');
p4 = plot(Eng_Spd,Eng_Trq,'.','color','k');
legend([p1 p4],{'Max Curve','Operating Points'});
axis([Eng_map_spd(1)*30/pi Eng_map_spd(end)*30/pi 0 Eng_map_trq(end)]);

%% Plotting motor operating points on engine fuel map
figure('Name','Motor Operating Points');
hold on
grid on
title('Motor Operating Points','fontsize',12);
p1=plot(EM_map_spd*30/pi,EM_max_trq,'linewidth',2,'color','r');
p2=line([EM_map_spd(end)*30/pi EM_map_spd(end)*30/pi],[0 EM_max_trq(end)]);
set(p2,'linewidth',1,'linestyle','--','color','k');
p3=line([EM_map_spd(1)*30/pi EM_map_spd(1)*30/pi],[0 EM_max_trq(1)]);
set(p3,'linewidth',1,'linestyle','--','color','k');
[c,h] = contour(EM_map_spd'*30/pi,EM_map_trq,EM_inpwr_map');
clabel(c,h);
xlabel(' Speed [rpm]');
ylabel(' Torque [Nm]');
title('powermap');
p4 = plot(out.EM_Spd,out.EM_Trq,'.','color','g');
legend([p1 p4],{'Max Curve','Operating Points'});
axis([EM_map_spd(1)*30/pi EM_map_spd(end)*30/pi 0 EM_map_trq(end)]);

Results for UDDS:

b. Plot the time trace for engine, transmission input, transmission output and wheel speed on one plot.

c. Plot engine torque, engine power, fuel rate and fuel consumption using subplots.

d. Plot accelerator and brake pedal, gear command, vehicle desired and actual speed, vehicle distance using subplots.

e. Plot the engine operating points on the engine fuel map.

f. Plot motor speed, torque, motor input power using subplots.

g. Plot pack voltage, current and SoC using subplots.

h. Plot the motor operating points on the motor input power map, with the motor max motoring and generating torque curves.

Results for HWFET: