Project 2

>Difference between P0 and P1 mild hybrid architecture?

The primary advantage of a P1 mild hybrid architecture, compared with P0, is the removal of the belt drive. This means that the efficiency increases a bit (no more belt losses) and the electric machine torque can be higher in terms of amplitude and response (no more belt slip).

>The P1 architecture, with the electric machine connected directly to the crankshaft, is the solution adopted by Honda on their first 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 advantage of this solution is that the electric motor can provide higher torque than the BiSG, since there is no belt limitation (due to slip). 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

>The main characteristics of the crankshaft-mounted electric machine for mild hybrid Honda Insight 2009.

1.Electric machine performance

Maximum torque (at crankshaft) is up to 34 Nm
Maximum power: 10 kW
Efficiency: up to 94%

2.Hybrid modes

idle Stop & Start
Moving Stop & Start
Engine load shift
Torque assist (fill)
Torque boost
Sailing / Coasting
Energy recuperation
Brake regeneration

3.Advantages

Higher efficiency
The 12V starter can be removed

4.Disadvantages

Output torque limited by the size of the electric machine
Energy recuperation affected by engine friction losses
High impact on existing vehicle architecture
Higher overall cost of the electrical components
Air cooling not possible for the electric machine

5.Overall characteristics

Torque Boosting Capability: High
Electrical Energy Recuperation: Medium
Driveability Improvements: Medium
Electrical Creep / Drive: Possible
System Efficiency: High

Procedure:

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 reference. 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.

>> Loading the Project2 folder and Run the “Project2_InitFile.m” Matlab script.

%% 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

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 = 2; % 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);

> Files loaded into the Matlab screen:

>Here all the files are loaded into the workspace and running of the given file which displays in the screen.

> After loading the file run the simulink model whcih was already created in the previous challange.

Simulink Vehicle model:

> Now we are going into detailes of the subsystem and how it works and what are intenal subsystems it contains.

1.Driver:

>The state flow chart consists of modes like ,1,2,3 and Engine on condition,EM throttel control.

>The inputs are Acceleration,Brake,Engine speed,Velocity and State of charge.

>outputs are as Mode,Engine on,Engine throttle.

>The state 1 and 2 are connected using the links i.e it moves from state 1 to 2 when acceleration is less than the one or SOC is less than the minimum soc.

>The state 3 represents mode 2 i.e engine is on and the engine throttle is also having positive value from the driver but the electronic motor throttle is zero.it changes from state 2 to 3 when engine speed is greater than or equal to engine idle speed.

>The state 4 represents regenrative braking whcih is model 3 in this state the engine is on but the engine throttle is having no input from driver where as the electric motor receives the negative power due to braking.

Engine control unit:

>The Engine control unit consists of 1D-look up tables,Idle speed controller as an subsystems.

Idle speed controller:

Transmission control unit:

>Here it consists of gear shift logical unit whcih requires Throttle,vehicle speed as input and Gear command as output.

Shift logic:

Threshold calculation:

EM control unit:

Brake control unit:

> In thiss the brake torque and all the control signals outputs are given directly to powertrain.

3.Powertrain:

> Here the poowertrain contains the engine,elctric motor,crankhub,Transmission.differential,wheels,and vehicle dynamic subsystems and also receives the inputs from the control unit and output is as velocity.

Engine:

>The Engine speed gives the required torque from the controller,and is saturated between the Max torque curve and min torque curve and passes the engine torque to the Transmission block.

>The 2D look up table is used to claculate the fuel fow rate based on the engine trq,speed.The fuel flow rate is then integrated to find the fuel flow consumption.

>The estimated fuel flow rate ,fuel consumption,engien torque and engine speed are passed to the Matlab workspace using the workspace block.

Electric Motor:

Crankhub:

Transmission:

> In this model we take engine torque,gear selector from controller for transmission of gear ratio.The ratio is multiply by transmission input torque and the transmission efficiency positive and negative torque gives transmission input speed.

Torque converter:

Differential:

Wheels:

Vehicle Dynamics:

ESS Unit:

ESS Simulation:

SOC Simulation:

Terminal Voltage simulation:

Post-Processing:

> A matlab script is created to analyse the data and to generated plots.Here we rename the variables loaded from the model,do some basic post-processing calculations and generates the results and plots.

%% 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)]);

>After executing the file we get desired plots with combination of all given data

Output plot:

Output Plots:

> By running the model we get desired plots.Here these are combination of UDDS,HWFET files.

1.Driver cycle:

Actual velocity and Drive cycle

2.Control signal:

Engine Torque,Transmission Gear,Brake Torque:

3.Powertrain:

Engine:

Engine Torque:

Engine Fuel rate and fuel consumption:

Transmission input and output speed,Gear ratio:

Torque Converter:

Differential Loads:

Axle torque and differential:

Wheel load:

Tractive force,Road load Acceleration, velcoity:

Tractive force and wheel speed:

Vehicle Dynamics: