Project 2
Aim: The task of this project is to quantify the improvement in fuel economy numbers for the hybrid vehicle (kmpl), compared to the conventional vehicle, on the urban cycle (UDDS) and highway cycle (HWFET). Also, to analyse and understand the vehicle operating points in terms of engine and motor speed, torque, transmission speeds, pedal positions, gear, distance travelled, battery voltage, current, SoC etc.
- First the initialization file is loaded into the MATLAB.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% Skill-Lync -> Hybrid Drives Development
% Project 2 - P1 Hybrid Vehicle Model
% 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);
Simulink Model:
- Here we start with modelled using a ‘Driver model' block, which is a basic PI controller that generates accelerator and brake pedal outputs to match the desired and actual vehicle speeds.
- The ‘Controller model’ 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 model’ block which represents the drivetrain of the vehicle. It consists of an ‘Engine model with Electric Motor’ connected to the ‘Automatic Transmission model’ 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 model’ block.
Driver Model:
- ‘Driver model' block, which is a basic PI controller that generates accelerator and brake pedal outputs to match the desired and actual vehicle speeds.
- the PI controller control the error between the required drive cycle and actual vehicle speed by providing acceleration and brake pedal output to the controller.
Controller Model:
- 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.
- a state flow machine is used to represent the supervisory control unit which decided the operating mode while it is start /stop mode or cruising mode or regen braking mode for each modes the engine drive and the motor driver are controlled.
Input to the state flow charts is acc and brake pedal input from the driver unit engine actual speed actual vehicle speed soc status ant the clutch lockup state and the output to the controller are the mode engine on /off request engine input throttle and electric motor input throttle. all control signal passed to transmission model which represent the drive train.
Engine control unit:
- Engine control unit compare engine speed with the maximum torque and minimum torque curve of the lookup table and give the required torque command to the engine block. the throttle input is combined with the idle speed throttle and gains with torque output from the lookup table to estimate the torque input required for the engine.
- Throttle input idle throttle and their sum can be scoped from this block.
Idle speed controller:
Transmission control block:
Simulink function for threshold calculaton:
Electric motor control unit:
Motor control unit compare EM speed with the max torque curve and max torque generation curve of the lookup table and give the required torque command to the electric motor the EM throttle input is used to compare the lookup table and to estimate the torque input required for the e-motor.
Brake control unit:
Brake control unit produce required brake torque according to the brake pedal input and passes the brake torque in to the wheel block in the transmission mode.
Battery model:
- A battery pack subsystem is created with electric power input and battery soc as output.
- 2 diff. subblock have been created to determine the soc and terminal voltage separately soc is used to determine the terminal voltage.
SOC Estimation model:
Pack current in ampere is converted to ampere and divides with max capacity and adds with the initial soc to determine the soc of the battery at each instance the soc value is limited between 0 to 1.
Terminal voltage model:
Ideal voltage and internal resistance are determined by 1D lookup table and battery voltage is determined using the model. The specified values are sent back to workspace using the to workspace block and can be used for postprocessing.
Engine model;
- Based on the engine speed the required torque from the controller is saturated between max torque curve and min torque curve and passes the engine torque to the transmission block.
- The 2D lookup table is used to calculate the fuel flow rate based on engine speed and engine torque.
- The new engine also has an on/off feature to eliminate the fuel flow rate when the engine is off also the engine torque cannot be negative torque as min. torque curve mode saturated.
- The fuel rate is then integrated to find the fuel consumption. Engine fuel flow rate and fuel consumption are scoped
Electric motor model:
Crank hub:
Differential Model:
Output:
Engine fuel rate and fuel consumption:
Engine torque:
Electric Motor Torque:
Crank Torque:
Gear ratio, Transmission input:
Pump Speed and Turbine Speed:
Post Processing:
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% Skill-Lync -> Hybrid Drives Development
% Project 2 - P1 Hybrid vehicle Model
% Description:
%% Initialization File
% Initialization file for loading the variables for the Conventional vehicle simulation model
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(1)
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(3,1,1)
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(3,1,2)
hold on
grid on
plot(Time, Gear_Cmd, 'linewidth', 1, 'Color', 'red');
ylabel('Gear')
xlim([0, Time(end)]);
legend('Gear_Cmd');
subplot(3,1,3)
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');
figure(5)
subplot(3,1,1)
hold on
grid on
plot(Time,out.EM_Trq,'linewidth',1,'color','red');
ylabel('Motor Torque[Nm]');
xlim([0,Time(end)]);
legend('Motor Trq');
subplot(3,1,2)
hold on
grid on
plot(Time,out.ElecPwr,'linewidth',1,'color','red');
ylabel('motor power (kw)');
xlim([0,Time(end)]);
legend('Motor power');
subplot(3,1,3)
hold on
grid on
plot(Time, out.EM_Spd, 'linewidth',1,'color','green');
xlim([0,Time(end)]);
xlabel('Time(s)');
ylabel('motor speed');
figure(6)
subplot(3,1,1)
hold on
grid on
plot(Time, out.term_volt,'linewidth',1,'color','green');
ylabel('Voltage(V)');
xlim([0,Time(end)]);
legend('voltage');
subplot(3,1,2)
hold on
grid on
plot(Time,out.soc,'linewidth',1,'color','red');
ylabel('SOC');
xlim([0,Time(end)]);
legend('SOC %')
subplot(3,1,3)
hold on
grid on
plot(Time,out.pack_Current,'linewidth',1,'color','blue');
ylabel('SOC');
xlim([0,Time(end)]);
xlabel('Time(s)');
ylabel('pack_current');
%% 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 motor operating points on engine fuel map
figure('Name','Motor Operating Points');
hold on
grid on
title('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(' Speed [rpm]');
ylabel(' Torque [Nm]');
title('powermap');
p4 = plot(out.EM_Spd,out.EM_Trq,'.','color','g');
legend([p1 p4],{'Max Curve','Operating Points'});
axis([EM_map_spd(1)*30/pi EM_map_spd(end)*30/pi 0 EM_map_trq(end)]);
UDDS cycle:
Engine torque, engine power, fuel rate and fuel consumption:
Accelerator and brake pedal, gear command, vehicle desired and actual speed, vehicle distance using subplots
Engine operating points:
HWFET cycle:
Conclusions:
- Therefor the forward energy-based fuel consumption model of a P1 Hybrid vehicle has been successfully simulated using MATLAB and SIMULINK.
- Analysis and understand vehicle operating points based on engine speed, torque, transmission speed, pedal position, gear, distance, velocity, acceleration, battery, voltage, current, SOC and pedal position.
- Successfully calculated vehicle fuel efficiency number[kmpl] for the given city cycle [UDDS] and highway cycle[HWFET].and also compared to the conventional vehicle.