Project 1

Project :1

Aim Project 1:- It deals with the development of a forward energy-based fuel consumption model of a conventional vehicle.The main goal of this project is to get familiar with the modeling process, writing scripts in Matlab, modeling in Simulink, analyzing data and generating plots.

procedure as followed :-

1)Intially load the data from question and run matlab code.

2)After that Simulink block of engine and vehicle dynamic is buildup.and run simulink model

3)And the Post processing file is run and getting the results for different cycle as below .

4)Tabulate the fuel economy numbers (kmpl) for UDDS and HWFET cycle.

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

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

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

8) Plot the engine operating points on the engine fuel map.

9)Generate the plots for both drive cycles.

10) Study of Conventional vehicle simulink model and creates graphs.

Initial program file code :

Drive cycle :UDDS(urbon dynamometer drive cycle )

%% Skill-Lync -> Hybrid Drives Development

% Project 1 - Conventional Vehicle Model

% 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

%% Driver Parameters

Kp = 10; % P gain for driver PI model

Ki = 1; % I gain for driver PI model

Drive_Cycle_Select = 1; % 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);

similarly for HWEFT cycle we have to run the initial file and after that simulink model run . then post processing run and get plots for different conditions .

Simulink model : Engine and Vehicle dynamics block is build as below .

1)engine

Scope of engine :

2) Vehicle Dynamics block :

scope of vehicle dynamics :

Overall Driver model :-

Controller model :

Powertrain model

After that post processing file is run and matlab code as below :

%% Skill-Lync -> Hybrid Drives Development

% Project 1 - Conventional Vehicle Model

% By - Ullekh Gambhira

% Description:

% The following file is to used with the Initialization file and Simulink

% results for post-processing of the data.

% The file is incomplete, has some examples of how the data is imported

% into a readable format, data analysis and plotting examples.

% Based on the project task, use commands in a similar format as given

% below, to analyse the data and generate required plots.

% You can change variable names if desired

%% Post-Processing File

% File for post-processing the Conventional 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]

Veh_Dist = out.Veh_Dist/1000; % Distance traveled by vehicle [km]

Veh_Spd = out.Veh_Spd*18/5; % Vehicle speed [kmph]

%% 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()

subplot(3,1,1)

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');

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, Gear_Cmd, 'linewidth', 1, 'Color', 'black');

xlim([0, Time(end)]);

xlabel('Time [s]');

ylabel('Gear');

%% 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)]);

Scope:-

We can see that the graph has more fluctuations in UDDS compared to the HWFET cycle because UDDS has more startsand stops due to urbon conditions but HWFET does not have too many starts and stops Braking is high in UDDS when compared to HWFET due to traffic Peak engine power reached in UDDS is nearly 4800 RPM and that in HWFET is 3800 RPM at the start, because, in UDDS, the vehicle requires more power to start from the initial condition.Engine torque, engine power, fuel rate, and fuel consumption plot:

1)for UDDS cycle :-(Urbon Dynamometer drive cycle ):

Drive cycle :scope

2) HWFET(highway fuel economy test ):

1) Fuel economy of UDDS cycle :

As we see, the fuel economy is high in HWFET compared to UDDS, it is because, in urban driving, the vehicle encounters more

traffic and it has to stop for fewer distances and it consumes more fuel at the starting. In HWFET, the vehicle encounters no traffic and it moves without use of too much braking, so it will have more fuel economy number.

Fuel economy for HWFET :-

V

Accelerator and brake pedal chart for UDDS Cycle :

As in HWFET Cycle frequent stops ie brake opearted and in Udds cycle more stopages is occure . also similarly effects on speed . That is in highway speed is high and in UDDS cycle comparativly speed is less. Also gear selection drive changing phenomenon is more in UDDS cycle as compare to HWFET cycle Vehicle consumed more power in the UDDS compared to HWFET cycle because it has too many starts and stops compared to HWFET. When starting from the initial condition vehicle requires more power Engine torque is also high in UDDS because while starting from rest, the vehicle requires more torque to overcome the static
friction

Accelerator and brake pedal chart for HWFET Cycle :

Tme series plot for UDDS Cycle :-

Velocity and distance plot For UDDS Cycle :

Velocity and distance plot For HWFET Cycle :

Road loads graph:- As the graph for both cycle shown. In UDDS Cycle

1)UDDS Cycle 2)HWEFT Cycle

Conclusions :-

For UDDS, the accelerator and the brake pedal have more fluctuations because of frequent starts and stops. But in HWFET, the
brake pedal fluctuations are almost near to the zero line as there will be no frequent stops UDDS cycle mostly runs on 1st, 2nd gears, and uses 3rd, 4th gears very rarely as it does not achieve high speeds in that traffic. In the HWFET cycle, the vehicle mostly runs on 3rd, 4th gears as it will be moving at high speeds. It uses 1st, 2nd gears very frequently when braking is required So that , the vehicle speeds will be high in HWFET compared to UDDS. so that fuel also consumption is more in UDDS cycle as move in 1 and 2 gear as compare to HWFET cycle .