Challenge

Project 1

SSaurabh Kshirsagar17 Sept 2023

HTML MATLAB

AIM:

The development of a conventional vehicle's forward energy-based fuel consumption model using Matlab and Simulink.
To compute the fuel economy numbers for the given desired vehicle model in kmpl on the two different drive cycle types are UDDS and HWFET.
By understanding the vehicle operation points in terms of engine speed, torque, transmission speeds, Pedal Position, gear, and Distance traveled
By Simulating the model using blocks
To write the Scripts for a MATLAB for loading all the variables to perform the simulation
Analyze the data and create a plot by using MATLAB.

Objective:

Tabulate the fuel economy numbers (kmpl) for UDDS and HWFET cycles. This forms the baseline numbers for comparing with the future hybrid version.
Plot the time trace for engine, transmission input, transmission output, and wheel speed on one plot.
Using subplots, plot engine torque, power, fuel rate, and consumption.
Using subplots, plot accelerator and brake pedal, gear command, vehicle desired and actual speed, and vehicle distance.
Plot the engine operating points on the engine fuel map.
Write down appropriate brief comments on each of these plots, describing the vehicle behavior throughout the drive cycle.
Generate the plots for both drive cycles

Thesis:

Forward-Modelling of Vehicle Approach:

This kind of approach is known as the cause-effect, engine-to-wheel or rear-to-front method, the direction of calculation is the same as the direct positive power flow method: power flow is from the engine to the wheel.
This approach is based on the vehicle dynamics equation and the behavior of single powertrain components and their dynamic interaction between the wheels.
A Driver Controller is required to control the vehicle to follow desired speed and to calculate.
The Controller is implemented to model that the driver will either push the accelerator or the brake pedal to match the desired speed which enables to study the braking of the vehicle
It also acts as a feedback loop for the vehicle which was used to determine the energy requirements to drive the vehicle.

Convectional Vehicle Modelling:

Basic architecture model of forwarding Vehicle Modeling:

The Simulation Process is been processed in 3 different stages:

Pre-processing
Simulation
Post-processing

Stage 1:

Pre-Processing

In this Stage data which load as a program, it will take as an input program of the vehicles which is used for Post-processing of the Simulation by using the Simulink Model which is already built

Drive Cycle selection is also done from here by choosing the variable in it eg:1 is for UDDS, 2 is for HWFET, and 3 is for FTP.

Before running the Simulink model we have to induce inputs variables to the workspace to use by the Simulink model.

Inputs such as:

Mass of the vehicle (M) in kg

Coefficient of Rolling resistance (Cr)

Rolling Radius (Rw) in m

Drag Coefficient (Cd)

Frontal Area (Af) in m^2

Air density (rhoa) in kg/m^3

Wind Velocity (Vwind) in kmph

Gravitational Force (g) in m/s^2

Slope (theta) in deg

Here the Input Data of the Vehicle Dynamics is Consists of a typical 4-gear vehicle

Below I have attached the input program for the simulation:

�scription:

%% 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);

Drive Cycle which was used in this program is US-based Vehicles Dynamics

By the Changing the variable input for selecting different Drive_cycle

1 UDDS

2 HWFET

3 FTP

4 US06

5 NEDC

6 WLTP

Simulink Modeling:

The Model of Simulink is for the convection model of the vehicle in which it has been divided into 3 main sub-blocks are:

Driver
Controller
Powertrain

The Actual Vehicle speed is given as feedback to the driver block, and the driver block gives into the controller block in which the acceleration or brake output is connected.

While the controller provides a control signal for engine torque, gear shifting, and brake torque to the powertrain block.

Controller Unit:

The brain of the vehicle unit is the 'Controller' block, which represents the ECU, Transmission Unit, and Basic Control Unit

Based on the Driver Inputs, it generates desired engine Torque, desired transmission gear, and desired brake torque. These will be sent as feedback to the powertrain blocks as input which is represented the drivetrain of the vehicle.

Driver:

In this Driver Block, it is a basic PI controller model that is used to generate accelerator and brake pedal Outputs that are used to match the desired and actual vehicle speeds.

The PI controller controls the error between the required drive cycle and the actual vehicle speed is been provided by the acceleration and brake pedal output of the controller unit.

Controller:

Engine Control Unit:

In this Block, ECU is the main unit that used to run the vehicle

Inputs such as Engine Speed, Maximum Torque Curve, Minimum Torque Curve, Idle Speed Control and the output is Engine Torque.

Transmission Control Unit:

This Control unit has 2 inputs whereas Throttle, Vehicle Speed, and Gear Command as Output.

Has Increasing the Input Throttle speed, Changing of gear commands take place accordingly 1,2,3,4 and vice versa for speed dropping condition.

The Gear command is been created by using the Stateflow block for this simulation.

It is been controlled accordingly by Vehicle Speed and Throttle inputs.

The gear command is been passed to the transmission block to select the desired gear ratio.

Basic Control Unit:

It consists of the basic control unit which requires brake torque according to the brake pedal input and passes the brake torque into the wheel block in the transmission model.

The second Block of this Vehicle Model is 'Powertrain':

Powertrain:

To move up the vehicle we need a Body structure that is used to move the vehicle in forward and reverse directions as required.

It consists of all components that will convert the Fuel power of the engine for the motion to move the vehicle.

It consists of an Engine, Transmission, Wheels, Differential, Vehicle Dynamics

Transmission Control Unit:

This Control unit has 2 inputs whereas Throttle, Vehicle Speed, and Gear Command as Output.

Has Increasing the Input Throttle speed, Changing of gear commands take place accordingly 1,2,3,4 and vice versa for speed dropping condition.

The Gear command is been created by using the Stateflow block for this simulation.

It is been controlled accordingly by Vehicle Speed and Throttle inputs.

The gear command is been passed to the transmission block to select the desired gear ratio.

Basic Control Unit:

It consists of the basic control unit which requires brake torque according to the brake pedal input and passes the brake torque into the wheel block in the transmission model.

The second Block of this Vehicle Model is 'Powertrain':

Powertrain:

To move up the vehicle we need a Body structure that is used to move the vehicle in forward and reverse directions as required.

It consists of all components that will convert the Fuel power of the engine for the motion to move the vehicle.

It consists of an Engine, Transmission, Wheels, Differential, Vehicle Dynamics

Engine Model:

Based on the Engine Speed, the required torque from the controller is between Max torque and Min Torque curve and it will transfer the Engine Torque to the Transmission Block.

The 2D lookup table is used to calculate the fuel rate and is then integrated to find the fuel consumption rate of the engine, by using the engine speed and engine torque.

By using the 'To Workspace' block command the estimated fuel flow rate, fuel consumption, engine torque, and engine speed is been passed to the workspace of MATLAB.

Transmission Model:

The input of the block is coming from the Engine model named 'Engtrq'.

This input is connected to Torque Converter and this output is connected to a differential which is named 'TransOutTrq'.

Torque Converter:

A torque converter is a type of fluid coupling that transfers rotating power from a prime mover, like an internal combustion engine, to a rotating driven load. In a vehicle with an automatic transmission, the torque converter connects the power source to the load. It is usually located between the engine's flexplate and the transmission. The equivalent location in a manual transmission would be the mechanical clutch.

Differential:

The Transmission output torque is multiplied by the differential ratio and differential eff in these blocks and the torque is transmitted to the wheel as the axle torque.

Wheel Model:

This takes input from brake torque in the control model is been subtracted from the axle torque and divided from the rolling radius to determine the tractive force.

The wheel speed is calculated from the vehicle velocity and saved into the workspace.

Vehicle Dynamics:

This block consists of the longitudinal dynamics of the vehicle which consists of Aerodynamics force, Rolling Resistance Force, Grade Force etc..,

Formulas used:

where

ρ</math>">ρ�a - Air Density

Af - Frontal Area

Cd-Drag Coefficient

M - mass of a vehicle

g - Acceleration due to gravitational force

θ</math>">θ� - Slope angle

These variables have already been preloaded to the workspace using a MATLAB script

%% Post-Processing File

% File for post-processing the Conventional vehicle simulation model data

%% Renaming variables

Time = out.tout;

Acc_Pdl = out.Acc_Pdl; �celerator 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_Consumption = out.Eng_Fuel_Consumption; % Engine fuel Consumptiontion [g]

Veh_Dist = out.Veh_Dist/1000; % Distance traveled by vehicle [km]

Veh_Spd = out.Veh_Spd*18/5; % Vehicle speed [kmph]

Whl_Spd=out.Whl_Spd*30/pi; %Wheel Speed [kmph]

Eng_Fuel_Rate=out.Eng_Fuel_Rate; %Engine Fuel Rate(%)

%�ta Analysis

Eng_Pwr = Eng_Spd.*pi/30.*Eng_Trq./1000; % Engine brake power [kW]

rho_petrol = 0.7197; �nsity of petrol [kg/L]

kmpl = Veh_Dist(end)./(Eng_Fuel_Consumption(end)./1000./rho_petrol); % Fuel economy [kmpl]

%Display Fuel Economy of the Cycle

fprintf('nFuel Economy = %2.2fkmplnn',kmpl);

%% Plotting vehicle characteristics time trace

%Plotting TransIn,TransOut,Wheel Spd

figure(1)

subplot(3,1,1)

hold on

grid on

plot(Time,Trans_In_Spd,'linewidth',1,'color','black');

xlabel('Time[S]')

ylabel('Speed[rpm]')

xlim([0,Time(end)]);

legend('Trans Input');

subplot(3,1,2)

hold on

grid on

plot(Time,Trans_Out_Spd,'linewidth',1,'color','r');

xlabel('Time[S]')

ylabel('Speed[rpm]')

xlim([0,Time(end)]);

legend('Trans Output');

subplot(3,1,3)

hold on

grid on

plot(Time,Whl_Spd,'linewidth',1,'color','g');

xlabel('Time[S]')

ylabel('Speed[rpm]')

xlim([0,Time(end)]);

legend('Wheel Speed');

%Plotting Eng_trq,Eng_power,Fuel_rate,Fuel_Consumptiontion

figure(2)

subplot(4,1,1)

hold on

grid on

plot(Time, Eng_Trq ,'linewidth',1,'color','b');

ylabel('Torque[Nm]')

xlim([0,Time(end)]);

subplot(4,1,2)

hold on

grid on

plot(Time,Eng_Pwr,'linewidth',1,'color','cyan');

ylabel('Power[Kw]')

xlim([0,Time(end)]);

subplot(4,1,3)

hold on

grid on

plot(Time,Eng_Fuel_Rate,'linewidth',1,'color','r');

xlabel('Time[s]')

ylabel('Eng Fuel Rate')

xlim([0,Time(end)])

subplot(4,1,4)

hold on

grid on

plot(Time,Eng_Fuel_Consumption,'linewidth',1,'color','b');

xlabel('Time[s]')

ylabel('Fuel Consumptiontion [g]')

xlim([0,Time(end)]);

%plot acc,brake pedal gear command and actual spd,Veh_dist

figure(3)

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, Gear_Cmd, 'linewidth', 1, 'Color', 'black');

xlim([0, Time(end)]);

xlabel('Time [s]');

ylabel('Gear');

subplot(3,1,3)

hold on

grid on

plot(Time,Veh_Dist,'Linewidth',1,'color','black')

xlabel([0,Time(end)]);

ylabel('Dist [Km]');

%% Plotting Drive Cycle

figure(4)

hold on

grid on

plot(cyc_time,cyc_vel,'linewidth',1,'color','black');

xlabel('Time[s]')

ylabel('Velocity[mph]')

title('Drive Cycle')

%% 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 Consumptiontion 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)]);

Conclusion:

Hence the forward energy-based fuel consumption model of a conventional vehicle has been successfully simulated using MATLAB and Simulink.

Analyses and understands vehicles operating points based on engine speed,Torque,Transmission inputs & output speed, Pedal Positions, gear, and Distance travelled by the vehicle.

Post-Porcessing is most efficiently used to calculate the performance and require graph and it is been successfully plotted above.

Successfully Calculated vehicle fuel efficiency numbers (kmpl) for the given cycles such as UDDS and HWFET.

Project 1

Ship work like this
in your own course.

Talk to a career counsellor

Ship work like thisin your own course.

Talk to a career counsellor

Ship work like this
in your own course.