Project 1

Description:
Project 1 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.

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.

“Project1_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.

“Project1_VehicleModel.slx” is the Simulink model of the vehicle. It is modeled using a ‘Driver’ block, which is a basic PI controller that generates accelerator and brake pedal outputs to match the desired
and actual vehicle speeds. 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 transmission gear
and desired brake torque. These inputs are fed to the ‘Powertrain’ block which represents the drivetrain of the vehicle. It consists of an ‘Engine’ connected to the ‘Automatic Transmission’ through a ‘Torque
Converter’. The output of the transmission is connected to the ’Differential’, which powers the ‘Wheels’, that provides the tractive force for vehicle acceleration. The longitudinal dynamics of the vehicle along with the road load is represented in the ‘Vehicle Dynamics’ block. The solver selected is ode3 with a fixed step size of 0.01 sec.

After running this Simulink model, data from the model will be loaded in the Matlab workspace.

“Project1_ProcessingFile.m” is the 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. Here we
rename the variables loaded from the model (if desired), do some basic post-process calculations and generate results and plots.

Task:
The task of this project is to compute the fuel economy numbers for the given vehicle (kmpl) on the urban cycle (UDDS) and highway cycle (HWFET). Also, to analyze and understand the vehicle operating
points in terms of engine speed, torque, transmission speeds, pedal positions, gear, distance traveled, etc.

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

1) Load the Project1 folder as the Current Folder in Matlab.
2) Run the “Project1_InitFile.m” Matlab script.
3) The provided vehicle Simulink model “Project1_VehicleModel.slx” is incomplete. The engine and vehicle dynamics block contents have been deleted. Build the Simulink blocks by referring to the course lecture and example block images provided. You can run the model and analyze the results using a ‘Scope’ for debugging.
4) Add additional ‘To Workspace’ blocks for transferring the desired Simulink vehicle data into the Matlab workspace.
5) Modify the “Project1_ProcessingFile.m” as per the desired plots and required calculations.
6) Write a project report that contains the following:

a. Tabulate the fuel economy numbers (kmpl) for UDDS and HWFET cycle. This forms the baseline numbers for comparing with the future hybrid version.
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. Write down appropriate brief comments on each of these plots, describing the vehicle behavior throughout the drive cycle.
g. Generate the plots for both drive cycles

Click here to download the attachment

Solution

Load the Project1 folder as the Current Folder in Matlab.

• Run the “Project1_InitFile.m” Matlab 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);​

• 
• Once the code runs all variableswill be entered into work space.
• Before running the simulink model complete the engine and vehicle dynamics blocks building. Ignore velocity multiplication in the vehicle dynamics image given in the file. No changes in the engine block. Engine block

  The block we can develop using week6 s-4 and week 4 s-4. Replace the variable names in the look up table mentioned in the work space for fuel consumption, Max Torque curve and Minimum Torque curves.

  

• vehicle dynamic block

  • Add additional ‘To Workspace’ blocks for transferring the desired Simulink vehicle data into the Matlab workspace.

  Ex: veh_sped, veh_Dist shown in above figure.

  • Modify the “Project1_ProcessingFile.m” as per the desired plots and required calculations.
  • Program has been modified as per the requirements and the program is given 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]
  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()
  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(4,1,1)
  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(4,1,2)
  hold on
  grid on
  plot(Time, Gear_Cmd, 'linewidth', 1, 'Color', 'red');
  ylabel('Gear')
  xlim([0, Time(end)]);
  legend('Gear_Cmd');
  subplot(4,1,3)
  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');
  subplot(4,1,4)
  hold on
  grid on
  plot(Time,Veh_Dist, 'linewidth', 1, 'Color', 'black');
  xlim([0, Time(end)]);
  xlabel('Time [s]');
  ylabel('Veh_Dist');
  legend('Veh_Dist');
  
  
  %% 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)]);
  

• 
• UDDS Outputs.

a)Tabulate the fuel economy numbers (kmpl) for UDDS and HWFET cycle. This forms the baseline numbers for comparing with the future hybrid version.

UDDS KMPL

46522.2116448191

HWFET KMPL

64304.7677894190

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

b)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.

FOR HWFET CYCLE:

For this in the drive cycle select=2 for UDDS it will be 1

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.

Observation: By using HWFET drive cycle vehicle reaches 64304.7677894190 kmph.

By using UDDS drive cycle vehicle reaches 46522.2116448191 Kmph.