Project 1
Development of a forward energy-based fuel consumption model of a conventional vehicle
Conventional vehicles are run by internal combustion engines powered by either petrol or diesel. They run on the principle of otto cyle or diesel cycle. The burning of air fuel mixture inside the engine cylinder generates pressurized gases that forces the cylinder downwards, This rotates the crankshaft. The mechanical energy then travels through thr clutch, gearbox and differential finally to the wheels.
In this project, a typical midsize car with a 1.9L engine and a 4-speed automatic transmission is considered. Data is taken from ADVISOR data base developed by NREL, USA. Transmission shift map and controller is taken from Matlab/Simulink example database.
The model developed has the capability to simulate the vehicle on different drive cycles like UDDS, HWFET, FTP, NEDC, etc.
Initial Matlab Code
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% Skill-Lync -> Hybrid Drives Development
% Project 1 - Conventional Vehicle Model
% By - Antarip Sinha
% 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);Simulink Model
Driver block
In this block we get accelerator and brake pedal outputs by the driver to get a desired vehicle speed.
Driver block plot
Controller block
This block has the electronic control units. It generates signals for Engine operations, Gear changing, Brake etc based on the given input from the driver block.
Controller block plot
Powertrain block
This block represents the drivetrain of the vehicle. It has the Engine block which gives input to the Transmission, the transmission then transfer the power to the differential. The differential block transfers powers to both the wheels as required.
Engine block
Engine block plot
Transmission block
In this block the torque converter takes energy input from the engine and transfers required torque in the differential.
Transmission block plot
Differential block
Wheels block
Vehicle dynamics block
The equation to calculate road load is
Vehicle dynamics block plot
Post Processing Code
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% Skill-Lync -> Hybrid Drives Development
% Project 1 - Conventional Vehicle Model
% By - Antarip Sinha
% 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 and Data conversion from double timeseries
Time = out.tout;
Acc_Pdl = out.Acc_Pdl; % Accelerator pedal [%]
Acc_pdl = Acc_Pdl.Data(:,1);
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_trq = Eng_Trq.Data(:,1);
Eng_Spd = out.Eng_Spd*30/pi;% Engine speed [rpm]
Eng_spd = out.Eng_Spd.Data(:,1);
Eng_Fuel_Consumption = out.Eng_Fuel_Consumption; % Engine fuel consumption [g]
Eng_Fuel_consumption = Eng_Fuel_Consumption.Data(:,1);
Veh_Dist = out.Veh_Dist/1000; % Distance traveled by vehicle [km]
Veh_dist = Veh_Dist.Data(:,1); %Vehicle distance
Veh_Spd = out.Veh_Spd*18/5; % Vehicle speed [kmph]
Veh_spd = Veh_Spd.Data(:,1);
Wheel_Spd = out.WheelSpeed;
Wheel_spd = Wheel_Spd.Data(:,1);
Eng_Fuel_Rate = out.Eng_Fuel_Rate;
Eng_Fuel_rate = Eng_Fuel_Rate.data(:,1);
%% Data Analysis and data conversion from double timeseries
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_Consumption(end)/1000/rho_petrol); % Fuel economy [kmpl]
%% Plotting time trace for engine, transmission input, transmission output and wheel speed
figure(1)
hold on
grid on
plot(Time,Eng_spd,'linewidth',1,'color','r');
plot(Time,Trans_In_Spd,'linewidth',1,'color','g');
plot(Time,Trans_Out_Spd,'linewidth',1,'color','blue');
plot(Time,Wheel_spd,'linewidth',1,'color','yellow');
xlabel('Time [s]');
ylabel('Speed [rpm]')
xlim([0, Time(end)]);
ylim([0, 6000]);
legend('Transmissiom Input','Transmission Output','Engine Speed','Wheel Speed');
%% Plotting engine torque, engine power, fuel rate and fuel consumption
figure(2)
grid on
subplot(2,2,1)
plot(Time,Eng_trq,'linewidth',1,'color','red');
xlabel('Time [s]');
ylabel('Torque[Nm]');
subplot(2,2,2)
plot(Time,Eng_Pwr,'linewidth',1,'color','b');
xlabel('Time [s]');
ylabel('Power[KW]');
subplot(2,2,3)
plot(Time,Eng_Fuel_rate,'linewidth',1,'color','g');
xlabel('Time [s]');
ylabel('Fuel Rate[%]');
subplot(2,2,4)
plot(Time,Eng_Fuel_consumption,'linewidth',1,'color','y');
xlabel('Time [s]');
ylabel('Fuel Consumption[kmpl]');
%% Plotting accelerator and brake pedal, gear command, vehicle speed
figure(3)
subplot(3,1,1)
grid on
hold on
plot(Time,Acc_pdl,'linewidth',1,'color','r');
plot(Time,Brk_Pdl,'linewidth',1,'color','black');
xlabel('Time [s]');
ylabel('Pedal[%]')
xlim([0, Time(end)]);
legend('Accelerator','Brake');
subplot(3,1,2)
grid on
hold on
plot(Time,Veh_spd,'linewidth',1,'color','blue');
xlabel('Time [s]');
ylabel('Speed [rpm]')
xlim([0, Time(end)]);
legend('Time');
subplot(3,1,3)
grid on
hold on
plot(Time,Gear_Cmd,'linewidth',1,'color','g');
xlabel('Time [s]');
ylabel('Gear')
xlim([0, Time(end)]);
legend('Time');
%% 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
For UDDS cycle
Time trace for engine, transmission input, transmission output and wheel speed
engine torque, engine power, fuel rate and fuel consumption
accelerator and brake pedal, gear command, vehicle speed
For HWFET cycle
To run the HWFET cycle we just have to write Drive_Cycle_Select = 2 and run the code then the simulink model and finally the post processing code again.
Time trace for engine, transmission input, transmission output and wheel speed
engine torque, engine power, fuel rate and fuel consumption
accelerator and brake pedal, gear command, vehicle speed
