Project 2
Aim:- Modeling of development of a forward energy-based fuel consumption model of a P1 hybrid vehicle.
Theory:-
P1 Mild Hybrid Electric Vehicle:-
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
For example, the main characteristics of the P1 MHEV.
1] ELectric Machine Performance:-
Maximum torque up to 34 Nm.
Maximum power: 10KW
Efficiency: Up to 94 Percent
2] Hybrid Modes:- Idle stop and stop
Moving stop and start
Engine load shift T
orque assist
Torque boost
Energy recuperation
Brake generation
3] Advantages:-
Higher efficiency
The 12V starter can be removed
4] Disadvantages:-
Output torque limited by thje size of the elctric 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 electric machine
5] Overall charcteristics:-
Toruqe Boosting capacity: High
Electrical energy recuperation: Medium
Driveability improvements: Medium
Electrical Creep/drive: Possible
In this model We use Forward Model:- It 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 simulatios are more realistic due to phhysical casualty hence appropriate for control development. There is 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.
SIMULINK MODEL:-
1] Layout:
2]Driver:
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. In this we use drive cycles fro the based on these results of fuel consumption and emissions the vehicle gets certified and it also forms a basis of uniform asessment. It is based on time, velocity then its all integrate and creates output accelration pedal and brake pedal.
3]Controller:
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 desired motor torque and desired brake torque. These inputs are fed to the ‘Powertrain’ block which represents the drivetrain of the vehicle. In this we require to create stateflow block it explain in next figure.
4] Stateflow for Controller:-
In this we created four conditions as stop, start, drive and regenration braking. The initial block represent the stop condition. In which the engine is off. The engine and motor throttle conditions are zero. Then the second block represent start condition. In which the mode is 1 the electric motor throttle is only used to provide the required torque and power to the vehicle. the engine is off and engine throttle conditionis zero.
The state 1 and state 2 are connected using the links i.e. it moves from state 1 to state 2 when acceleration is less than one or SOC is less then the minimum SOC.
State 3 Represtents mode 2 ii.e. engine is on and the engine throttle is also having positive value from the driver but the electric motor throttle is zero. It changes form state 2 to state 3 when engine speed is graeter than or equal to engine idle speed.
state 4 represents regenrative braking which is model 3 In this state the engine is on but the engine throttle is having no input from driver whereas the electric moto receives the negative power due to braking.
The inputs are given to chart is Acceleration, barke, engine speed, vehicle speed, SOC, and clutch lockup.
The output we get from the chart is mode, engine condition, engine throttle condition, and electric motor throttle condition.
Modification done in all Unit modeling. they showed in next figures.
5] Engine Control Unit:-
In this control model We use engine control unit in that give input Engine speed through creating look up table. in that table we give input Maximum torque and map speed then also create 2nd look up trable in that give input ct torque and map speed then it substracts and multiplied. the engine speed also give to ideal contro speed to integrate from this we meet output of engine required torque.
6] 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 give input to this steady state is vehicle speed in m/s to mph.
7] Shiftlogic In this unit:-
8] Threeshold Value in This controller:-
9] Electric Motor Control Unit:-
10] Brake Control Unit:-
POWERTRAIN
11] Engine:-
In 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.
12] Electric Motor:-
13] Crankhub:-
14] Transmission:-
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.
15]Torque Converter:
16]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.
17]Wheel:
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.
18]Vehicle Dynamics:
In this takes tractive force and road load. It is dictates vehicle speed based on tractive force and road load.
Battery Modeling:-
19] Estimated storage system:-
In this we give input as power then it multiply and give to pack current. then from soc estimation meet output SOC its give to terminal voltage as input and then meet terminal voltage as output.
20] Terminal Voltage:-
In this use input SOC it is connected to 1d lookup table 1st table variable interpolated as state of charge and open voltage circuit. In 2nd table variable interpolated as resistance discharge and state of charge and in 3rd table variable interpolated as resistance charge and state of charge. Then it is passed to switch block for controlling the threeshold. then they give voltage limits as max volts and min volts. then meet terminal Voltage.
21] Pack Current:-
In this we integrate pack current and convert it rad to amp then saturated and meet SOC.
%% Plotting Engine speed, Engine Torque, Engine Power,Engine fuel rate,Engine fuel consumption wrt Time
figure(2)
subplot(4,1,1)
plot(Time,Eng_trq,'linewidth',1,'color','black')
xlim([0, Time(end)]);
xlabel('Time [s]')
ylabel('Torque [Nm]')
legend('Engine Torque')
grid on
subplot(4,1,2)
plot(Time,Eng_pwr,'linewidth',1,'color','blue')
xlim([0, Time(end)]);
xlabel('Time [s]')
ylabel('Power [KW]')
legend('Engine Power')
grid on
subplot(4,1,3)
plot(Time,Eng_fuel_rate,'linewidth',1,'color','red')
xlim([0, Time(end)]);
xlabel('Time [s]')
ylabel('Fuel Rate [%]')
legend('Engine Fuel Rate')
grid on
subplot(4,1,4)
plot(Time,Eng_fuel_consumption,'linewidth',1,'color','green')
xlim([0, Time(end)]);
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');
ylabel('Pedal [%]')
xlabel('Time [s]');
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')
% Plotting gear command vehicle desired with actual speed
figure(5)
subplot(2,1,1)
plot(Veh_spd, Gear_Cmd, 'linewidth', 1, 'Color', 'black');
xlabel('Speed [rpm]');
ylabel('Gear');
grid on
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);
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 with respect to Time
figure(6)
subplot(3,1,1)
plot(Time,Pack_current,'linewidth',1,'color','black')
xlim([0, Time(end)]);
xlabel('Time [s]')
ylabel('Current [W]')
legend('Pack Current')
grid on
subplot(3,1,2)
plot(Time,State_of_charge,'linewidth',1,'color','blue')
xlim([0, Time(end)]);
xlabel('Time [s]')
ylabel('Charging [%]')
legend('State Of Charge')
grid on
subplot(3,1,3)
plot(Time,Term_voltage,'linewidth',1,'color','red')
xlim([0, Time(end)]);
xlabel('Time [s]')
ylabel('Voltage [V]')
legend('Terminal Voltage')
grid on
%% Motor Speed, Torque, Motor input power with respect to Time
figure(7)
subplot(3,1,1)
plot(Time,EM_power,'linewidth',1,'color','black')
xlim([0, Time(end)]);
xlabel('Time [s]')
ylabel('Power [W]')
legend('Electric Motor Power ')
grid on
subplot(3,1,2)
plot(Time,EM_torque,'linewidth',1,'color','blue')
xlim([0, Time(end)]);
xlabel('Time [s]')
ylabel(' Torque [Nm]')
legend('Electric Motor Torque')
grid on
subplot(3,1,3)
plot(Time,EM_speed,'linewidth',1,'color','red')
xlim([0, Time(end)]);
xlabel('Time [s]')
ylabel('Speed [Rpm]')
legend('Electrical Motor Speed')
grid on
%% Plotting EM Operating Points on motor input power Map
figure('Name','Electric Motor Operating Points');
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_map_trq(end)]);
Que:- Tabulate the fuel economy numbers (kmpl) for UDDS and HWFET cycle. Compare these numbers with the baseline numbers for conventional vehicle model from Project 1.
Answer:-
Fuel Economy Numbers for project 2
| S.No | Drive cycle | Fuel Economy Number (KMpl) |
| 1 | UDDS | 15.0773 |
| 2 | HWFET | 17.1613 |
As we see 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 stop for fever distance and it consumes more fuel at the starting. In HWFET the vehicle encounters no traffic and it moves without use of too much braking so it will have more fuel economy number.
Comparing with fuel economy numbers for project 1
| S.No | Drive cycle | Fuel Economy Number (KMpl) |
| 1 | UDDS | 14.209 |
| 2 | HWFET | 16.503 |
As we see the fuel economy numbers for project 2 are bit higher when compared to project 1 because of implementing the electric motor as it is P1 hybrid it may not have much variation in the fuel economy but as we implement other architechture it will increase by huge amount.
Answer:-
1] For UDDS drive cycle:-
2] For HWFET drive cycle:-
In this we can see the graph is more fluctuate into UDDS drive cycle compared to HWFET drive cycle. It is because UDDS has more starts and stops and in HWFET less starts and stops.
Braking is high in UDDS compared to HWFET.
Peaked engine power reached nearly 4200 RPM in UDDS drive cycle and in HWFET cycle it reached at 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:-
Vehicle cosumed more power in UDDS drive ccycle bacause in urban area the vehicle require many starts and stops so it required more power compred to HWFET.
Engine is high in UDDS drive cycle compred to HWFET drive cycle because the starting from rest the vehicle requires more torque to overcome the static friction.
The fuel rate is high in HWFET drive cycle compared to UDDS drive cycle because it will be in continues movement so it consumes more fuel.
The fuel economy is high in HWFET because In UDDS cycle many starts and stops so more fuel cosumes and the engine is in idle postion.
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 acceleratior and brake pedal have more fluctuations because of frequent starts and stops. but in HWFET the brake pedal fluctuations are almost near to t he zero line as there will be no frequent stops.
Que:- Plot the engine operating points on the engine fuel map.
Answer:-
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 UDDS cycle compared to HWFET cycle because UDDS has many starts and stops due to traffic as the purpose of motor in P! hybrid is initiation of crank rotation and they are more in UDDS cycle when compared to HWFET cycle.
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 HWFET cycle because of the frequent start and stops throughout the drive and the battery has to provide the energgy everytime when the car is starting from the idle position.
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:-
Fuel Economy wrt Time:-
1] For UDDS drive cycle:-
2] For HWFET drive cycle:-
Conclusion:-
The various performance of characteristics and operating points of UDDS drive cycle and HWFET drive cycle are analysed and the graphs are plotted
- Time trace for engine, Transmission input, Transmission output and wheelspeed with respect to time.
- Engine torque, Engine power, Fuel rate and Fuel consumption with respect to time.
- Accelerator and brake pedal, gear command and vehicle desired, actual speed, vehicle distance with respect to time.
- Engine operating points on the engine fuel map with respect to time.