Challenge

Project 2

JJaswanth Sai Padugupadu1 Sept 2022

MATLAB

ANSWER:

AIM:

Modeling of development of a forward energy-based fuel consumption model of a P1 hybrid vehicle.

OBJECTIVES:

Tabulate the fuel economy numbers [kmpl] for UDDS and HWFET cycle. Compare these numbers with the baseline numbers for conventional vehicle model.
Plot the time trace for engine, transmission input, transmission output and wheel speed on one plot.
Plot engine torque, engine power, fuel rate and fuel consumption using subplots.
Plot accelerator and brake pedal, gear command, vehicle desired and actual speed, vehicle distance using subplots.
Plot the engine operating points on the engine fuel map.
Plot motor speed, torque, motor input power using subplots.
Plot pack voltage, current and SoC using subplots.
Plot the motor operating points on the motor input power map, with the motor max motoring and generating torque curves.
Write down appropriate brief comments on each of these plots, describing the vehicle behavior throughout the drive cycle.
Generate the plots for both drive cycles

THEROY:

Forward Model Approach:

The forward modelling approach is also known as cause-effect, engine-to-wheel or rear-to-front method. The direction of calculation is the same as the direction of positive power flow, from engine-to-wheel.
This approach is based on vehicle dynamics equations and the behaviour of each powertrain components and their dynamic interaction.
Moreover, a driver controller is required to control the vehicle to follow a desired speed and set the start of the
calculations. The controller is implemented to model the driver that will either push the accelerator or the brake
pedal to match the desired speed which enables to study the driver behaviour. The controller is used as part of
a feedback loop that will determine the energy required to drive the vehicle.

P1 Hybrid:

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.

VEHICLE MODEL Pre-Processing

A MATLAB script has been created to load all the variables needed to run and post-process the Simulink model.
Drive cycle selection is also done from here. Before running the Simulink vehicle model, the script is initialized at MATLAB to load all the variables in the workspace.

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% Skill-Lync -> Hybrid Drives Development
% Project 1 - Conventional Vehicle Model
% By - Padugupadu Jaswanthsai 

% Description:

%% Initialization File
% Initialization file for loading the variables for the Conventional vehicle simulation model

%% Vehicle Parameters
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);

The Drive Cycle can be selected from this MATLAB Script, By changing the variable Drive _Cycle _Select to

UDDS
HWFET
FTP
USO6
NEDC
WLTP

VEHICLE MODEL:

The Simulink model for the convection model is created using 3 main sub-blocks for the driver model, control model and powertrain block.
The actual vehicle speed is given as feedback to the driver block, and the driver block gives the controller block the required acceleration or brake output, while the controller block provides control signals for engine torque, gear shifting and brake torque to the Powertrain model.

Driver Model:

Driver Model is a basic PI controller that generates accelerator and brake pedal outputs to match the desired and actual vehicle speeds.

The PI controller controls the error between the required drive cycle and actual vehicle speed by providing acceleration and brake pedal output to the controller.

Controller Model :

The 'Controller block is the brains of the vehicle, representing the electronic controls units. Based on the driver
inputs, it generates desired engine torque, desired motor torque, desired transmission gear and desired brake
torque. These inputs are fed to the 'Powertrain' block which represents the drivetrain of the vehicle.

The Input to the state flow charts is Acceleration and Brake pedal input from the driver unit, Engine actual
speed, Actual vehicle speed, SOC status and the clutch lockup state. And the State flow Outputs to the
individual controllers are the Mode, Engine On/ off request, Engine input throttle and Electric motor input Throttle
The controller consists of an engine control unit, a transmission control unit, Electric Motor control unit and a
brake control unit.
All control signals re passed to transmission model which represents the drive train.

Engine control unit:

Engine control unit compare engine speed with the maximum torque and minimum torque curve of the lookup table and give the required torque command to the engine block. the throttle input is combine with the idle speed throttle and gains with torque output from the lookup table to estimate the torque input required for the engine.
throttle input idle throttle and their sum can be scoped from this block.

Idle speed controller:

Transmission control block:

Electric motor control unit:

Motor control unit compare EM speed with the max torque curve and max torque generation curve of the lookup table and give the required torque command to the electric motor the EM throtle input is used to compare the lookup table and to estimate the torque input required for the e-motor.

Brake control unit:

Brake control unit produce required brake torque according to the brake pedal input and passes the brake torque in to the wheel block in the transmission model.

Powertrain model:

The powertrain model includes all the components that convert the power of the engine into vehicle motion.
This includes Engine, Battery Pack, Electric Motor, Crank Hub, Transmission, Differential, Wheels and the vehicle
body dynamics subsystems.
The control signals from the control model are transmitted via a bus to the corresponding blocks in the
powertrain model.

Battery Model:

SOC Estimation model:

Pack current in ampere is converted to amphr and divides with max capacity and adds with the initial soc to determine the soc of the battery at each instance the soc value is limited betwen 0 to 1.

Terminal voltage model:

Ideal voltage and internal resistance are determined by 1D lookup table and battery voltage is determoned using the model.
the specified values are send back to workspace using the to workspace block and can be used for post processing.

Engine model:

Based on the engine speed the required torque from the controller is saturated between max torque curve and min torque curve and passes the engine torque to the transmission block
The 2D lookup table is used to calculate the fuel flow rate based on engine speed and engine torque.
The new engine also has an on/off feature to eliminate the fuel flow rate when the engine is off also the engine torque cannot be negative torque as min.torque curve mode saturated.
The fuel rate is then integrated to find the fuel consumption.
Estimated fuel flow rate fuel consumption engine torque and engine speed are passed to the MATLAB workspace using the to-workspace block
Engine fuel flow rate and fuel consumption are scope.

Electric motor model:

Based on the engine speed the required EM torque from the cotroller is saturated between max EM torque curve and max EM torque generation curve and passes the EM torque to the crank hub
The 2D lookup table is used to calculate the input electric power to the motor basd on the EM speed and EM torque.

Crank hub:

Crank hub adds up the EM torque and the engine torque and pass it to the transmission block as the crank torque.

Transmission model:

In these model we take engine torque, gear selector from controller for transmission of gear ratio. The ratio is multiply by transmission input torque and then the transmission efficiency positive torque and negative torque gives transmission input speed. In this case torque converter connects the engine to transmission it is part of transmission. In it basically engine dynamics and that is decoupled.

Torque converter:

The gear selection from the transmission control unit is multiplied by the engine torque in this block and the efficiency and engine dynamics of the torque converter are applied in this model.

Differential Model:

In this taking input is the transmission output then it’s going to the differential ratio multiplied the output and input torque then meet axle torque. The axle torque is a lower than the transmission torque and differential ratio.

Wheel Model:

The brake torque from the control model is subtracted from the axle torque and divides from the rolling radius to determine the tractive force
The wheel speed is calculated from the vehicle velocity and saved in the workspace.

Vehicle dynamics:

The longitudinal dynamics of the vehicle along with the road load is represented in the vehicle dynamics block.
Tractive force and road loads are used to calculate the vehicle velocity.

Where,

The variable are loaded on the workspace using MATLAB scripts.
The acceleration velocity and distance travelled are calculated and stored in the workspace.

Post processing:

Matlab script used to analyze this data and to generate plots. This script needs to be executed after the Simulink model data has been loaded into the workspace. the variables loaded from the model (if desired), do some basic post-process calculations and generate results and plots.

%% Hybrid Drives Development
% Project 2 - P1 Hybrid Vehicle Model
% By - Padugupadu Jaswanthsai

%% Post-Processing File
%  File for post-processing the P1 Hybrid vehicle simulation model data

%% Renaming variables
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]
Eng_Fuel_Rate = out.Eng_Fuel_Rate;   %engine fuel rate
Veh_Dist = out.Veh_Dist/1000;   % Distance traveled by vehicle [km]
Veh_Spd = out.Veh_Spd*18/5;     % Vehicle speed [kmph]
Whl_Spd = out.Whl_Spd*30/pi;     % wheel speed[RPM]
Desired_spd = out.Desired_Velo*18/5 ;  %desired speed [KMPH]
EM_Spd = out.EM_Spd*30/pi;         % E motor speed[rpm]
EM_Trq = out.EM_Trq;               % E motor torque[Nm]
EM_Pwr = out.EM_Pwr;               % E motor input power[W]
V_batt = out.V_battery;              % battery pack voltage [V]
I_batt = out.I_battery;              % battery pack current [I]
SOC = out.SOC;                     % STATE OF CHARGE [%]
RS = out.RS;                       % internal resistance
VOC = out.VOC;                     % open circuit voltage

%% 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];

 
% display fuel Economy of the cycle
formatspec = 'fuel economy is %2.2f kmpl';
fprintf(formatspec,kmpl);


%% Plotting vehicle characteristics time trace

% ploting transmission input,transmission output and wheel speed 
figure(1)
hold on
grid on
plot(Time,Trans_In_Spd,'LineWidth',1,'Color','black');
plot(Time,Trans_Out_Spd,'LineWidth',1,'Color','red');
plot(Time,Whl_Spd,'LineWidth',1,'Color','blue');
xlabel('Time[s]')
ylabel('speed[rpm]')
xlim([0,Time(end)]);
legend('trans input','trans Output','wheel speed');
title('transmission input transmission output and wheel speed')

% plotting engine torque,engine power,fuel rate ,fuel consumption
figure(2)
subplot(4,1,1)
hold on
grid on 
plot(Time,Eng_Trq,'LineWidth',1,'Color','black');
ylabel('torque[NM]')
xlim([0,Time(end)]);
title('Engine Torque')

subplot(4,1,2)
hold on
grid on 
plot(Time,Eng_Pwr,'LineWidth',1,'Color','black');
ylabel('power[KW]')
xlim([0,Time(end)]);
title('Engine Power')

subplot(4,1,3)
hold on
grid on 
plot(Time,Eng_Fuel_Rate,'LineWidth',1,'Color','black');
xlim([0,Time(end)]); 
xlabel('Time[s]');
ylabel('Engine fuel rate');
title('Engine fuel rate')

subplot(4,1,4)
hold on
grid on 
plot(Time,Eng_Fuel_Consump,'LineWidth',1,'Color','black');
xlim([0,Time(end)]);
xlabel('Time[s]');
ylabel('Engine fuel consumption[g]');
title('Engine Fuel Consumption')

% plotting accelerator and brake pedal gear command vehicle desired and actual speed ,vehicle distance
figure(3)

subplot(4,1,1)
hold on
grid on
plot(Time, Acc_Pdl, 'linewidth', 1, 'Color', 'black');
plot(Time, Brk_Pdl, 'linewidth', 1, 'Color', 'red');
ylabel('Pedal [%]')
xlim([0, Time(end)]);
legend('Accel','Brake');
title('Acceleration and brake pedal inputs')

subplot(4,1,2)
hold on
grid on
plot(Time, Gear_Cmd, 'linewidth', 1, 'Color', 'black');
xlim([0, Time(end)]);
xlabel('Time [s]');
ylabel('Gear');
title('gear command')

subplot(4,1,3)
hold on
grid on
plot(Time, Veh_Spd, 'linewidth', 1, 'Color', 'black');
plot(Time, Desired_spd, 'linewidth', 1, 'Color', 'red');
ylabel('Speed [kmph]')
xlim([0, Time(end)]);
legend('actual speed','desired speed');
title('vehicle actual and desired speed')

subplot(4,1,4)
hold on
grid on
plot(Time, Veh_Dist, 'linewidth', 1, 'Color', 'black');
xlim([0, Time(end)]);
xlabel('Time [s]');
ylabel('distance[km]');
title('vehicle distance')

% plotting drive cycle
figure(4)
hold on
grid on
plot(cyc_time,cyc_vel,'LineWidth',1,'Color','black')
xlabel('time[s]')
ylabel('velocity[mph]')
title('drive cycle')

% test result
Avg_speed = sum(Veh_Spd)/length(Veh_Spd);
Max_speed = maxk(Veh_Spd,1);
table (Avg_speed,Max_speed,kmpl,'variablenames',{'average speed[kmph]','maximum speed[kmph]','fuel economy[kmpl]'})

%% Plotting engine operating points on engine fuel map
figure('Name','Engine Operating Points');
hold on
grid on
title('Engine Operating Points','fontsize',12);
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]');
legend({'Max Curve','Operating Points'});
axis([Eng_map_spd(1)*30/pi Eng_map_spd(end)*30/pi 0 Eng_map_trq(end)]);

%% Electric Motor
% plotting motor speed ,motor torque,motor input power

figure(6)
subplot(3,1,1)
hold on 
grid on
plot(Time,EM_Spd,'LineWidth',1,'Color','b');
ylabel('Speed[rpm]')
xlim([0,Time(end)]);
title('motor speed')

subplot(3,1,2)
hold on 
grid on
plot(Time,EM_Trq,'LineWidth',1,'Color','r');
ylabel('torque[Nm]')
xlim([0,Time(end)]);
title('motor torque')

subplot(3,1,3)
hold on 
grid on
plot(Time,EM_Pwr,'LineWidth',1,'Color','g');
ylabel('power[W]')
xlim([0,Time(end)]);
title('motor input power')

%% BATTERY
% plotting pack current,voltage,soc,internal resistance,open circuit
% voltage

figure(7)

subplot(5,1,1)
plot(Time,V_batt,'LineWidth',1,'Color','r');
xlabel('Time[sec]');
ylabel('voltage[v]');
title('pack voltage')
xlim([0,Time(end)]);
grid on

subplot(5,1,2)
plot(Time,I_batt,'LineWidth',1,'Color','b');
xlabel('Time[sec]');
ylabel('current[I]');
title('battery current')
xlim([0,Time(end)]);
grid on

subplot(5,1,3)
plot(Time,SOC,'LineWidth',1,'Color','g');
xlabel('Time[sec]');
ylabel('SOC[%]');
title('STATE OF CHARGE')
xlim([0,Time(end)]);
grid on

subplot(5,1,4)
plot(Time,RS,'LineWidth',1,'Color','r');
xlabel('Time[sec]');
ylabel('Internal resistance[ohm]');
title('Internal resistance')
xlim([0,Time(end)]);
grid on

subplot(5,1,5)
plot(Time,VOC,'LineWidth',1,'Color','b');
xlabel('Time[sec]');
ylabel('Open circuit voltage[v]');
title('Open circuit voltage')
xlim([0,Time(end)]);
grid on

%% Plotting engine operating points on engine fuel map
figure('Name','Electric motor Operating Points');
hold on
grid on
title('Electric motor Operating Points','fontsize',12);
p1=plot(EM_map_spd*30/pi,EM_max_trq,'linewidth',2,'color','r');
p4=plot(EM_map_spd*30/pi,EM_max_gen_trq,'LineWidth',2,'Color','b');
p2=line([EM_map_spd(end)*30/pi EM_map_spd(end)*30/pi],[EM_max_gen_trq(end) 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],[EM_max_gen_trq(1) EM_max_gen_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('Motor Speed [rpm]');
ylabel('motor Torque [Nm]');
title('Motor in power map [W]');
legend([p1 p4 p3],{'Max Curve','regen curve','Operating Points'});
xlim([EM_map_spd(1)*30/pi EM_map_spd(end)*30/pi]);
ylim([EM_max_gen_trq(1) EM_max_trq(1)]);

Post Processing Results:

Drive Cycle:

a) UDDS

b) HWFET:

Fuel economy numbers(KMPL):

a) UDDS:

b) HWFET:

The time trace for engine ,transmission input,transmission output,wheel speed:

a) UDDS:

b) HWFET:

Much of the fluctuating input speed is facilitated by the torque convertor and the transmission input speed fluctuates according to the engine torque required to achive the drive cycle.
Wheel speed and transmision output speed vary according to gear and differential ratio.

Engine torque,engine power,fuel rate,fuel consumption:

a) UDDS:

b) HWFET:

The torque requirements of the drive cycle are different so the fuel flow rate varies and fuel consumption is calculated.
The HWFET drive cycle has higher power and torque requirement and less negative torque and power.

Accelerator and brake pedal,gear command,vehicle desired and actual speed,vehicle distance:

a)UDDS:

b)HWFET:

Acceleration and brake pedals are used more bcoz the drive cycle is not very smooth and the gear has to be shifted frequently.

Brake requirement are lower more acceleretor pedal are applied on the highway drive cycle and gear shift often occurs the drive cycle is smoother.
Acceleration and brake pedal the gear command of the transmission control unit the required speed of the vehicle the actual speed and the actual vehicle distance are plotted.

The engine operating points on the engine fuel map:

a) UDDS:

b)HWFET:

The engine operating points are plotted on the fuel map and the operating points is under the maximum torque curve.

The motor speed,motor torque,motor input power:

a)UDDS:

b) HWFET:

The pack voltage ,current,SOC, VOC,internal resistance:

a)UDDS:

b) HWFET:

The motor operating points on the motor inputs power map,with the motor max motoring and generating torque curves:

CONCLUSION :

The various performance of characteristics and operating points of UDDS drive cycle and HWFET drive cycle are analysed and the graphs are plotted

Time trace for engine, Transmission input, Transmission output and wheelspeed with respect to time.
Engine torque, Engine power, Fuel rate and Fuel consumption with respect to time.
Accelerator and brake pedal, gear command and vehicle desired, actual speed, vehicle distance with respect to time.
Engine operating points on the engine fuel map with respect to time.
Motor speed, Torque, Motor input power with respect to time.
Pack voltage, Current and State of charging with respect to time.
The motor operating points on the motor input power map with respect to time.and also it comparing with HWFET drive cycle and their numbers also compared.

Project 2

Ship work like this
in your own course.

Talk to a career counsellor

Ship work like thisin your own course.

Talk to a career counsellor

Ship work like this
in your own course.