Project 2
Aim: Modelling of the development of a forward energy-based fuel consumption model of a P1 hybrid vehicle.
Objectives:
1) Load the Project2 folder as the Current Folder in Matlab.
2) Run the “Project2_InitFile.m” Matlab script.
3) Copy the Conventional vehicle Simulink model created for Project 1 in this folder. Figure 1: P1 Hybrid ArchitectureHybrid Drives Development
4) Modify this model into a hybrid vehicle model. The lecture presentations can be used as references. Battery and Supervisory controller models developed in the assignments can be reused.
5) Add additional ‘To Workspace’ blocks for transferring the desired Simulink vehicle data into the Matlab workspace.
6) Simulate the hybrid model on the desired drive cycles.
7) Write a project report that contains the following:
a. Tabulate the fuel economy numbers (kmpl) for UDDS and HWFET cycle. Compare these numbers with the baseline numbers for the conventional vehicle model from Project 1.
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. Plot motor speed, torque, motor input power using subplots.
g. Plot pack voltage, current and SoC using subplots.
h. Plot the motor operating points on the motor input power map, with the motor max motoring and generating torque curves.
i. Write down appropriate brief comments on each of these plots, describing the vehicle behaviour throughout the drive cycle.
j. Generate the plots for both drive cycles
Theory:
P1 Mild Hybrid Electic Vehicle:
The p1 architecture, with the electric machine connected directly to the crankshaft, is the solution adopted by Honda on their 1st generation Integrated Motor Assist (IMA) technology. The electric motor functions as a generator, during vehicle deceleration, as an engine starter, and as a motor (to assist the engine) during vehicle accelerations. One of the biggest advantages of this solution is that the electric motor can provide higher torque than the BiSG since there is no belly limitation (due to slipping). however, since there is no speed/torque ratio between the electric machine and crankshaft, the torque requirements on the electric motor can be quite demanding.
Two examples of P1 MHEV architectures are:
- Honda Insight Hybrid 2009 (with Integrated Motor Assist technology)
- Mercedes Benz S400 Bluehybrid 2010
For example, the main characteristics of the P1 MHEV.
1) Electric Machine Performance:
Maximum Torque up to 34 Nm.
Maximum Power of 10kW
Efficiency up to 94 %
2) Hybrid Modes:
Idle stop and stop
Moving stop and start
Engine load shift
Torque assist
Torque boost
Energy recuperation
Brake generation
3) Advantages:
Higher efficiency
The 12V starter can be removed
4) Disadvantages:
Output torque is limited by the size of the electric machine
energy recuperation affected by engine friction losses
High impact on existing vehicle architecture
The higher overall cost of the electrical components
Air cooling is not possible for an electric machine
5) Overall characteristics:
Torque boosting capacity: High
Electrical energy recuperation: Medium
Driveability improvements: Medium
Electrical Creep/drive: Possible
In this model we use Forward Model:
It is also known as dynamic simulation. Dynamic models are used for detailed simulations. In this model force/torque/power is the input and the vehicle state variable velocity and acceleration are outputs. The models and simulation are more realistic due to physical causality hence appropriated for control development. There is a feedback loop to meet the desired vehicle state. It is mainly used to simulate a vehicle on a driving cycle to analyse the dynamic behaviour of the system helps significantly in control development.
Process:
Load the Project2 folder as the Current Folder in Matlab.
Run the “Project2_InitFile.m” Matlab script.
The Drive cycle selection is done here.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% Skill-Lync -> Hybrid Drives Development
% Project 1 - Conventional Vehicle Model
% By - Harshavardhana G
% 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 = 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);After running this program open the Simulink model.
Vehicle Model:
1] Layout:
2] Driver:
It is modelled 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. In this we use drive cycles from the based on these results of fuel consumption and emissions the vehicle gets certified and it also forms a basis pf uniform assessment. It is based on time, velocity then it all integrates and creates an output acceleration pedal and a brake pedal.
3] Controller Model:
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.
4] Stateflow for Controller:
First State-block is defined for the initial condition when vehicle in Stationary condition in Stop condition. When Mode = 0, Eng_on, Eng_thr and Em_thr are in Off(0) conditions.
The engine is in stop mode where the engine throttle and the electric motor throttle is zero at initial mode.
The second State-block is connected to the first State-block by connecting the link as INPUT LINK were Acc>1 or SOC>SOC_min.
Here the acceleration is more than one and the State of Charge is less than the SOC minimum.
The second State-block is defined for the condition when the vehicle is in Starting condition. When Mode = 1, Eng_on = 0, Eng_thr = 0, Em_thr = 100.
The engine is in start mode. Now engine throttle is zero but the electric motor throttle is about 100. movement of vehicles is about to happen.
The third State-block is connected to the second State-block by connecting the link as INPUT LINK was EngSpd >= Eng_idel_spd.
Here the input engine speed is greater than equal to the engine's ideal speed.
The third State-block is defined for the condition when the vehicle is in Driving condition. When Mode = 2, Eng_on = 1, Eng_thr = Acc, Em_thr = 0.
The engine is in driving mode. The vehicle is in movement condition. The engine has been started and the engine throttle depends upon acceleration and the electric motor throttle is zero.
The fourth State-block is connected to the third State-block by connecting the link as INPUT LINK were Spd>6 and Brk>=2 and SOC0.
Here speed has increased and the break is also working simultaneously and SOC is smaller than SOC maximum and Clutch Lookup is greater than zero.
The fourth State-block is defined for the condition when the vehicle is in Regeneration Brake condition. When Mode = 3, Eng_on = 1, Eng_thr = 0, Em_thr = -Brk.
It is regeneration brake mode. Here the engine is running mode and the engine throttle and electric motor throttle is in the negative break.
The third State-block is connected to the fourth State-block by connecting the link as OUTPUT LINK were Spd<=5 or Brk<1 or SOC>=SOC_max or CluctchLockup.
Here the speed is less than equal to 5 or break is less than 1 or SOC is greater than equal to SOC maximum or clutch lockup.
The first State-block is connected to the third State-block by connecting the link as OUTPUT LINK were after(1, sec) and Spd<0.5 and SOC>SOC_min and Acc==0.
If the engine speed is less than 0.5 and SOC is greater than SOC minimum and acceleration is equal to zero.
5] Engine Control Unit:
In this control model, we use an engine control unit that gives input as Engine speed through creating a lookup table. In that table, we give input Maximum torque and map speed, then also create 2nd lookup table that gives input ct torque and map speed which is saturated. Then these lookup tables are subtracted and multiplied. The engine speed is also given to ideal control speed to integrate from this we meet the output of the engine required torque.
6] Tranamission Control Unit:
In this unit, we create a steady flow variable state for controlling the gears of the vehicle as in ascending and descending order with respect to time, speed, distance and give input to this steady-state is vehicle speed in m/s to mph.
7] Shiftlogic in this unit:
8] Threshold value in this controller:
9] Electric Motor Control Unit:
10] Brake Control Unit:
In this calculated brake torque and then all five control signals output is given to the powertrain.
11] Powertrain:
The Powertrain encompasses every component that converts the engine's power into movement. This includes the engine, electric machine, crank hub, ESS, transmission, the driveshaft, differentials, axles; basically anything from the engine through to the rotating wheels.
12] Engine:
In this control model, we use an engine control unit that gives input Engine speed by creating a lookup table. In that table, we have given input Maximum torque and map speed then also created 2nd lookup table is that give input ct torque and map speed then it subtracts and multiplied. The engine speed also gives to ideal control speed to integrate from this we meet the output of the engine's required torque.
13] Electric Motor:
14] Crank Hub:
15] Transmission:
In these models, we take engine torque, gear selector from the controller for transmission of gear ratio. The ratio is multiplied by transmission input torque and then the transmission efficiency positive torque and negative torque gives transmission input speed. In this case, the torque converter connects the engine to the transmission it is part of the transmission. Init basically engine dynamics and that is decoupled.
16] Torque Converter:
17] Differential:
In this taking input is the transmission output then it's going to differential ratio multiplied the output and output torque then meet axel torque. The axel torque is lower than the transmission torque and differential ratio.
18] Wheels:
In this model, we take the axle torque from the differential and brake torque from the controller. It is subtracted and multiplied by rolling radius and velocity we meet the tractive force from the axle and brake torque and the wheel speed is met using velocity.
19] Vehicle Dynamics:
This takes tractive force and road load. it is dictated vehicle sped based on tractive force and road load.
The dynamics equation for calculating road load is
Then we calculate and integrate then we meet the acceleration of the vehicle and velocity of the vehicle it means vehicle distance and vehicle speed.
20] Estimated Storage System:
In this we give input as power then it is multiplied and given to pack current. Then from SOC estimation meet output SOC, it is given to terminal voltage as input and then meets terminal voltage as output.
20] Terminal Voltage:
In this input, SOC is connected to 1-D lookup table 1st table variable interpolated as a state of charge and open voltage circuit. In the 2nd table, variables are interpolated as resistance charge and state of charge. Then it is passed to the switch block for controlling the threshold. Then they give voltage limits as max volts and min volts, then meet terminal voltage.
21] Pack Current:
In this integrate pack current and convert it rad to the amp then saturated and meet SOC.
Matlab Program:
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% Skill-Lync -> Hybrid Drives Development
% Project 2 - Hybrid Vehicle Model
% By - Harshavardhana G
% Description:
% The following file is to use 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_Spd = out.WheelSpd; % % Wheel Speed [kmph]
Velocity = out.Velocity; % % Velocity in [m/s]
Eng_Fuel_Rate = out.Eng_Fuel_Rate; % Engine Fuel Rate
EM_Speed = out.EMSpd*18/5; % % Electric Motor Speed
EM_Power = out.EMPwr; % % Elecric Motor Power
EM_Torque = out.EMTrq; % % Electric Motor Torque
Term_Volt = out.term_volt; % % Terminal Voltage of battery
soc = out.SOC; % % State Of Charge
Pack_Current = out.Pack_Current; % % Pack Current of the Battery
%% 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 Trans Input & Output Speed and Wheel Speed wrt Time
figure ('Name','Trans Input & Output Speed and Wheel Speed wrt Time')
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_Spd, 'linewidth', 1, 'color', 'blue');
ylabel('Speed [rpm]');
xlabel('Time [sec]');
xlim([0, Time(end)]);
ylim([0, 5000]);
legend('Trans Input','trans Output','Wheel Speed');
title('Trans Input & Output Speed and Wheel Speed wrt Time');
%% 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_consumption = Eng_Fuel_Consump.Data(:,1); % Engine Fuel Consumption
Eng_fuel_rate = Eng_Fuel_Rate.Data(:,1); % Engine Fuel Rate
Veh_dist = Veh_Dist.Data(:,1); % Vehicle Distance
Veh_spd = Veh_Spd.Data(:,1); % Vehicle Speed
EM_speed = EM_Speed.Data(:,1); % Motor Speed
EM_power = EM_Power.Data(:,1); % Motor Power
EM_torque = EM_Torque.Data(:,1); % Motor Torque
Pack_current = Pack_Current.Data(:,1); % Pack Current of Battery
State_of_charge = soc.Data(:,1); % State od Charge
Term_voltage = Term_Volt.Data(:,1); % Terminal Voltage of Battery
% Plotting Engine Torque, Engine power, Engine Fuel Rate and Engine Fuel Consumption
figure ('Name','Engine Torque, Engine power, Engine Fuel Rate and Engine Fuel Consumption')
subplot(4,1,1)
plot(Time,Eng_trq,'linewidth',1,'color','black');
xlabel('Time [sec]');
ylabel('Torque [Nm]');
legend('Engine Torque');
title('Torque wrt Time');
grid on
subplot(4,1,2)
plot(Time,Eng_pwr,'linewidth',1,'color','blue');
xlabel('Time [sec]');
ylabel('Power [kW]');
legend('Engine Power');
title('Power wrt Time');
grid on
subplot(4,1,3)
plot(Time,Eng_fuel_rate,'linewidth',1,'color','green');
xlabel('Time [sec]');
ylabel('Fuel Rate [%]');
legend('Engine Fuel Rate');
title('Fuel Rate wrt Time');
grid on
subplot(4,1,4)
plot(Time,Eng_fuel_consumption,'linewidth',1,'color','red');
xlabel('Time [sec]');
ylabel('Fuel Consumption');
legend('Engine Fuel Consumption');
title('Fuel Consumption wrt Time');
grid on
%% Plotting Fuel Economy Vs Engine Fuel Consumption
figure('Name','Engine Fuel Economy vs Engine Fuel Consumption')
plot(Eng_fuel_consumption,Eng_fuel_rate,'linewidth',1,'color','red');
xlabel('Fuel Consumption');
ylabel('Fuel Rate [%]');
legend('Fuel Economy vs Fuel Consumption');
title('Engine Fuel Economy vs Engine Fuel Consumption');
grid on
%% Plotting vehicle characteristics of Acc. & Brake Pedal, Trans Input & Output Speed and Gear Command wrt Time
figure ('Name','Acc. & Brake Pedal, Trans Input & Output Speed and Gear Command wrt Time')
subplot(3,1,1)
hold on
plot(Time, Acc_Pdl, 'linewidth', 1, 'Color', 'blue');
plot(Time, Brk_Pdl, 'linewidth', 1, 'Color', 'red');
ylabel('Pedal [%]')
xlim([0, Time(end)]);
legend('Accel','Brake');
title('Acceleration & Brake Pedal wrt Time');
grid on
subplot(3,1,2)
hold 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');
title('Trans Input and Output Speed wrt Time');
grid on
subplot(3,1,3)
plot(Time, Gear_Cmd, 'linewidth', 1, 'Color', 'green');
xlim([0, Time(end)]);
xlabel('Time [s]');
ylabel('Gear');
title('Gear Command wrt Time');
grid on
%% Plotting gear command vehicle distance with actual speed
figure ('Name','Vehicle distance and Actual speed wrt Gear Command')
subplot(2,1,1)
plot(Veh_spd,Gear_Cmd,'linewidth',1,'color','black');
xlabel('Speed [rpm]')
ylabel('Gear')
title('Gear Command wrt Vehicle Speed')
grid on
subplot(2,1,2)
plot(Veh_dist,Gear_Cmd,'linewidth',1,'color','blue');
xlabel('Distance [km]')
ylabel('Gear')
title('Gear Command wrt Distance')
grid on
%% 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');
xlabel('Engine Speed [rpm]');
ylabel('Engine Torque [Nm]');
legend([p1 p3],{'Max Curve','Operating Points'});
axis([Eng_map_spd(1)*30/pi Eng_map_spd(end)*30/pi 0 Eng_map_trq(end)]);
figure('Name','Fuel Consumption Map');
hold on
grid on
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]');
legend([p1 p3],{'Max Curve','Operating Points'});
axis([Eng_map_spd(1)*30/pi Eng_map_spd(end)*30/pi 0 Eng_map_trq(end)]);
%% State of Charge, Pack Current, and Terminal Voltage wrt Time
figure ('Name','State of Charge, Pack Current, and Terminal Voltage wrt Time')
subplot(3,1,1)
hold on
plot(Time, Pack_current, 'linewidth', 1, 'Color', 'blue');
ylabel('Current [W]')
xlabel('Time [sec]')
xlim([0, Time(end)]);
legend('Current');
title('Current wrt Time');
grid on
subplot(3,1,2)
hold on
plot(Time, State_of_charge, 'linewidth', 1, 'Color', 'red');
ylabel('Charging [%]')
xlim([0, Time(end)]);
xlabel('Time [sec]');
legend('State Of Charge');
title('State Of Charge wrt Time');
grid on
subplot(3,1,3)
plot(Time, Term_voltage, 'linewidth', 1, 'Color', 'black');
xlim([0, Time(end)]);
xlabel('Time [s]');
ylabel('Voltage [V]');
legend('Terminal Voltage')
title('Terminal Voltage wrt Time');
grid on
%% Motor Speed, Torque, Motor Input Power wtr Time
figure ('Name','Motor Speed, Torque, Motor Input Power wrt Time')
subplot(3,1,1)
hold on
plot(Time, EM_power, 'linewidth', 1, 'Color', 'blue');
ylabel('Power [W]')
xlabel('Time [sec]')
xlim([0, Time(end)]);
legend('Electric Motor Power');
title('Electric Motor Power wrt Time');
grid on
subplot(3,1,2)
hold on
plot(Time, EM_torque, 'linewidth', 1, 'Color', 'red');
ylabel('Torque [Nm]')
xlim([0, Time(end)]);
xlabel('Time [sec]');
legend('Electric Motor Torque');
title('Electric Motor Torque wrt Time');
grid on
subplot(3,1,3)
plot(Time, EM_speed, 'linewidth', 1, 'Color', 'black');
xlim([0, Time(end)]);
xlabel('Time [s]');
ylabel('Speed [rpm]');
legend (' Electric Motor Speed')
title('Electric Motor Speed wrt Time');
grid on
%% plotting EM Operating points on Motor Input Power Map
figure ('Name','Electric Motor Operating Ponts');
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');
p2 = line([EM_map_spd(end)*30/pi EM_map_spd(end)*30/pi], [0 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], [0 EM_max_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 Input Power Map [g/s]');
legend([p1 p3],{'Max Curve','Operating Points'});
axis([EM_map_spd(1)*30/pi EM_map_spd(end)*30/pi 0 EM_max_trq(end)]);
Que: Tabulate the fuel economy numbers (kmpl) for UDDS and HWFET cycle. Compare these numbers with the baseline numbers for the conventional vehicle model from Project 1.
Answer:
Fuel Economy Numbers for Project 2
S.No Drive Cycle Fuel Economy Numbers (kmpl)
1 UDDS 15.0773
2 HWFET 17.1613
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 top for fever distance and it consumes more fuel at the starting. In HWFET the vehicle encounters no traffic and it moves without the use of too much braking so it will have more fuel economy numbers.
Fuel Economy Numbers for Project 1
S.No Drive Cycle Fuel Economy Numbers (kmpl)
1 UDDS 14.209
2 HWFET 16.503
The fuel economy numbers for Project 2 are a bit higher when compared to Project 1 because of implementing the electric motor.
Que: Plot the time trace for engine, transmission input, transmission output and wheel speed on one plot.
Answer:
1] For UDDS drive cycle:
2] For HWFET drive cycle:
The graph is more fluctuated in the UDDS drive cycle compared to the HWFET drive cycle. It is because UDDS has more start and stop and HWFET has less start and stop.
Breaking is high in UDDS compared to HWFET.
Peaked engine power reached nearly 4200 rpm in the UDDS drive cycle and in the HWFET cycle it reached 3000 rpm
Que: Plot engine torque, engine power, fuel rate and fuel consumption using subplots.
Answer:
1] For UDDS drive cycle:
2] For HWFET drive cycle:
Engine torque is high in the UDDS drive cycle compared to the HWFET drive cycle because starting from the rest of the vehicle requires more torque to overcome the static friction.
Vehicle consumes more power in UDDS drive cycle because in an urban area the vehicle requires many starts and stops, so it requires more power compared to HWFET.
The fuel rate is high in the HWFET drive cycle compared to the UDDS drive cycle because it will be in continuous movement, so it consumes more fuel.
The fuel economy is high in HWFET because in the UDDS cycle many starts and stop so more fuel is consumed and the engine is in an idle position.
Que: Plot accelerator and brake pedal, gear command, vehicle desired and actual speed, vehicle distance using subplots.
Answer:
1] For UDDS drive cycle:
2] For HWFET drive cycle:
In UDDS the acceleration and brake pedal have more fluctuations because of the frequent starts and stop. But in HWFET the brake pedal fluctuations are almost near to the zero line as there will be no frequent stops.
In UDDS cycle mostly runs on 1st and 2nd gears and the 3rd and 4th gears are rarely used as it does not achieve high speed in that traffic. In the HWFET cycle, the vehicle mostly runs in 3rd and 4th gears as it will be moving at high speeds.
Que: Plot the engine operating points on the engine fuel map.
Answer:
Engine Operating Points
1] For UDDS drive cycle:
2] For HWFET drive cycle:
Fuel Consumption Map:
1] For UDDS drive cycle:
2] For HWFET drive cycle:
Fuel Economy wrt Time:
1] For UDDS drive cycle:
2] For HWFET drive cycle:
Que: Plot motor speed, torque, motor input power using subplots.
Answer:
1] For UDDS drive cycle:
2] For HWFET drive cycle:
The fluctuations will be more in the UDDS cycle compared to the HWFET cycle because UDDS has many starts and stop due to traffic as the purpose of the motor in P1 hybrid is the initiation of crank rotation and they are more in the UDDS cycle when compared to HWFET cycle.
If the purpose of the motor is to provide traction then both the cycles would have more fluctuations.
By observing the motor power and torque are high in HWFET at the start and they are almost zero after a few seconds but in UDDS it has continuous fluctuations this is because of frequent braking in UDDS.
Que: Plot pack voltage, current and SoC using subplots.
Answer:
1] For UDDS drive cycle:
2] For HWFET drive cycle:
The pack voltage and current will have more fluctuations in UDDS as compared to the HWFET cycle because of the frequent starts and stop throughout the drive and the battery has to provide the energy every time when the car is starting from the idle position.
SOC decreased in the UDDS cycle wrt time but it has increased in the HWFET cycle. It is because in UDDS we have frequent starts and stop and the battery has to provide the energy has every time when the car is starting from the idle position and the SOC decreases but in the HWFET cycle the vehicle will be moving continuously without braking frequently and the alternator is utilised to transfer some engine power to the battery through motor so SOC increases in the HWFET cycle.
Que: Plot the motor operating points on the motor input power map, with the motor max motoring and generating torque curves.
Answer:
1] For UDDS drive cycle:
2] For HWFET drive cycle:
Conclusion:
The various performance of characteristics and operating points of the UDDS drive cycle and HWFET drive cycle are analysed and the graphs are plotted.
- The time trace for engine, transmission input, transmission output and wheel speed on one plot.
- Engine torque, engine power, fuel rate and fuel consumption using subplots.
- Accelerator and brake pedal, gear command, vehicle desired and actual speed, vehicle distance using subplots.
- The engine operating points on the engine fuel map.
- Motor speed, torque, motor input power using subplots.
- Pack voltage, current and SoC using subplots.
- The motor operating points on the motor input power map, with the motor max motoring and generating torque curves.
and also it is compared with the HWFET drive cycle and their numbers are also compared.
End...
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