Project 1
Title
Deals with the development of a forward energy-based fuel consumption model of a conventional vehicle.
Aim:
1] Build Simulink model using blocks and complete the vehicle model.
23 Writting scripts in MATLAB to load all the variables required for running the Simulink model.
3] Tabulate the fuel economy numbers (kmpl) for UDDS and HWFET cycle.
4] Plot the time trace for engine. transmission input, transmission output and wheel speed on one plot.
5] Plot engine torque, engine power. fuel rate and fuel consumption using subplots.
6] Plot accelerator and brake pedal, gear command, vehicle desired and actual speed, vehicle distance using subplots
7] Plot the engine operating points on the engine fuel map.
8) Generate the plots for both drive cycles
9] Study of Conventional vehicle simulink model and creates graphs.
Conventional Vehicle:
Conventional vehicles use an internal combustion engine fueled by gasoline or diesel to power the wheels, in this the heat engine uses the principle of heat release through combustion of a fuel with an oxidizer in a combustion chamber to create expanding gases which pushes against a piston creating forcce and torque output.
In this vehicle engine converts chemical energy stored in the fuel into heat which is used to produce useful work. Typically use fossil fuels like petroleum (petrol and diesel).
The most popular type of engine is used in this system is 4 stroke reciprocating engine. Engine in cyclinder process can be represented by ideal thermodynamic cycles such as Otto cycle, Diesel cycle. Otto cycle is a ideal cycle thet describes the cycle process for spark ignited SI engine, and the Diesel cycle is the ideal cycle thet describes the cycle process for a compression ignited Cl engine
Energy and performance of vehicle
In this system trge power demand on the wheel need to instant supplied by the powertrain. In other word the power coming from the powertrain dictates the power dermand on the wheels (as per performance viz, acceleration, speed etc is determined by it
Conventional powwertrain efficiency:
The engine generates power by converting chemical energy stored into the mechanical energy by the process of combustion. This process of energy conversion also has an efficiency and the energy input is in the form of fuel consumption.
- Instantaneous fuel consumption is given as
It deals with the modeling of multi domain systems through the use of a unified approach based on a ordinary differential and algebraic equation describing the static and dynamic effects.
Each systems has are two generalised variables
1] Efforts:- It is generalised force variable, ex- torque, force, voltage, heating value.
2] Flow:- It is the generalised flow/velocity variable. ex:- velocity, current, mass flow rate.
MATLAB scripts:
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.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% Skill-Lync -> Hybrid Drives Development
% Project 1 - Conventional Vehicle Model
% By - Ullekh Gambhira
% 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);
lets see simulink model of conventional vehicle,
1.9L ADVISOR data base developed by NREL, USA. Transmission shift map and controller taken Matlab/Simulink example database.
developed capability simulate the vehicle different cycles like HWFET, FTP, etc.
"Project1_InitFile.m" Matlab variables required Simulink post-processing. cycle selection also done here. Before running the Simulink vehicle model, this initialization script
The 'Controller' block is the brains of the vehicle, representing the electronic controls units. It is based on the driver inputs, it generates desired engine torque, desired transmission gear and desired brake torque. These inputs are fed to the 'Powertrain' block which represents the drivetrain of the vehicle.
Transmission Control Unit
In this unit we create steadfy flow variable state for controlling of gears of vehicle as in ascending and descending order with respect to time, speed, distance, and is
3] PowerTrain:
The powertrain encompasses every component that converts the engine's power into movement. This includes the engine, transmission, the driveshaft, differentials, axles; basically anything from the engine through to the rotating wheels.
n this model we used map based model to model the fuel consumption of engine. It is based on maximum Torque and minimum torque from the controller, and then it saturated torque and give output then saturated torque and speed map give fuel consumption takes the speed and torque then the output goes into saturated then its integrated.
In these model we take engine torque, gear selector from controllerb 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.
Differential
In this taking input is the transmission output then its 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
In this model we take the axle torque from differentail and brake torque from controller, it is substracts and multiplied rolling radius and velocity then we meet the tractive force from axle and brake torque, and the wheelspeed is meet using velocity.
vehicle dynamics:
1)udds drive cycle
2)hwfet
CONCLUSION
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% 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]
Wheel_Speed=out.wh_speed;
Eng_Fuel_Rate=out.Eng_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 transmission IN/OUT 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, Wheel_Speed, 'linewidth',1, 'color', 'blue')
ylabel('Speed [rpm]')
xlabel('Timem [s]')
xlim([0, Time (end)]);
ylim([0,6000]);
legend('Trans Input', 'Trans Output', 'Wheel Speed');
%%Plotting vehicle characteristics time trace to Engine speed, Engine Torque, Engine Power,
% And Engine fuel rate, Engine fuel consumption
% Data conversion from Double Timeseries
Eng_spd=Eng_Spd.Data(:,1); % engine speed
Eng_trq= Eng_Trq.Data(:,1); % engine torque
Eng_pwr=Eng_Pwr.Data(:,1); % engine power
Eng_fuel_rate=Eng_Fuel_Rate.Data(:,1); % engine fuel rate
Eng_fuel_consumption = Eng_Fuel_Consump.Data(:,1); % engine fuel consumption
Veh_dist= Veh_Dist.Data(:,1); % vehicle distance.
veh_spd=Veh_Spd.Data(:,1); % vehicle speed
% Plotting Engine speed, Engine Torque, Engine Power, Engine fuel rate, Engine fuel consumption wrt
figure (2)
subplot (2,2,1)
plot(Time, Eng trq,'linewidth, 1,'color','black')
xlabel('Time [s]')
ylabel('Torque [Nm]')
legend('Engine Torque')
grid on
subplot (2,2,2)
plot(Time, Eng_pwr, 'linewidth',1, 'color', 'blue')
xlabel('Time [s]')
ylabel('Power [KW]')
legend('Engine Power')
grid on
subplot (2,2,3)
plot(Time, Eng_fuel_rate, 'linewidth',1, 'color', 'red')
xlabel( 'Time [s]')
ylabel('Fuel Rate [%]')
legend('Engine Fuel Rate')
grid on
subplot(2,2,4)
plot (Time,Eng_fuel consumption, 'linewidth',1, 'color', 'green')
xlabel('Time [s]')
ylabel('Fuel Consumption')
legend('Engine Fuel Consumption')
grid on
% Plotting fuel economy Vs Engine Fuel consumption
figure(3)
plot(Eng_fuel_consumption, Eng_fuel_rate, 'color', 'r')
xlabel('Fuel_consumption')
ylabel('Fuel_Rate [%]')
title('Fuel economy Vs Fuel consumption')
grid on
% Potting Accelerator pedal, Brake pedal and gear command with respect to time
figure(4)
subplot (2,1,1)
hold on
plot(Time, Acc_Pdl, 'linewidth', 1, 'Color', 'black');
plot (Time, Brk_Pdl, 'linewidth', 1, 'color', 'red');
xlabel('Time [s]');
ylabel('Pedal [%]');
xlim([0, Time(end)]);
grid on
legend( 'Accel', 'Brake');
title('Acceleration & Brake Pedal wrt Time')
subplot (2,1,2)
plot(Time, Gear_Cmd, 'linewidth', 1, 'Color', 'black');
xlim([0, Time(end)]);
xlabel('Time [s]');
ylabel('Gear');
grid on
title('Gear command wrt Time')
figure (5)
subplot (2,1,1)
plot (Veh_spd, Gear_Cmd, 'linewidth', 1, 'color', 'black');
xlabel('speed [rpm]');
ylabel('Gear');
title('Gear command wrt vehicle speed')
subplot (2,1,2)
plot (Veh_dist, Gear_Cmd, 'linewidth', 1, 'Color', 'red');
xlabel('Distance [kmpl]');
ylabel('Gear');
grid on
title('Gear command wrt Distance')
%% Plotting engine operating points on engine fuel map
figure('Name', 'Engine Operating Points');
hold on
grid on
title('Engine Operating Points', 'fontsize', 12);
pl=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_tra, Eng_fuel_map');
clabel (c,h);
xlabel('Engine Speed [rpm]');
ylabel('Engine Torque [Nm]');
title('Engine Fuel Consumption Map [g/s]');
legend ([p1 p3], ['Max Curve', 'Operating Points' });
axis ([Eng_map_spd (1) 30/pi Eng_map_spd (end) *30/pi e Eng_map_trq(end)]); Plot the time trace for engine, transmission input, transmission output and wheel speed on one plot.
Plot accelerator and brake pedal, gear command, vehicle desired and actual speed, vehicle distance using subplots.
PLOTTING FUEL ECONOMY VS FUEL CONSUMPTION
PLOTTING ACCELERATOR PEDAL, BRAKE PEDAL, GEAR COMMAND
PLOTTING GEAR COMMAND VEHICLE DESIRED WITH ACTUAL SPEED