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| %%% MAIN PROGRAM %%%
function [] = MainProgram(D);
%%% ENGINE DATA %%%
clear all
l = 0.214; %connecting rod length in meters
r = 0.065; %crank length in meters
ss = 2*r; %stroke in meters
Dp = 0.112; %cylinder bore/piston diameter in meters
lambda = r/l; %rod/crank relation
eps = 17.6; %compression ratio
Vd = 1.281e-3; %displacement per cylinder in m^3
Vc = Vd/(eps-1); %compression volume per cylinder in m^3
Vt = Vd+Vc; %total cylinder volume in m^3
Apis = pi*0.25*Dp^2; %piston area in m^2
Ahead = 0.015; %cylinder head area that transmits heat in m^2
%%% GEOMETRICAL DATA %%%
deguni = 360/1024; %degrees crank angle per units clock
TDC = 1025; %top dead center
BDC = TDC-512; %bottom dead center
ACDd = 38; %admission valve close delay in degrees
AOAd = 17; %admission valve opening advance in degrees
EOAg = 53; %exhaust valve opening advance in degrees
duradm = AOAd+180+ACDd; %duration of admission in degrees
AC = TDC-((180-ACDd)/deguni); %admission valve closing
ACr = round(AC); %round AC value
EO = TDC+((180-EOAg)/deguni); %exhaust valve opening
EOr = round(EO); %round EO value
%%% THERMODYNAMICAL DATA %%%
gm = 1.35; %gamma of the mixture of air and combustible
Rg = 287; %gas constant in J/(Kg*K)
percent = 0.25; %percentage value at which the heat release starts
percentinj = 0.15; %percentage value at which injection starts
D(1,1)=input('Insert the number of revolutions (in rpm): ');
D(2,1)=0;%input('Insert the brake force (in N): ');
D(3,1)=input('Insert the consumption time (in s): ');
D(4,1)=input('Insert the admission air quantity (in cm): ');
D(5,1)=input('Insert the test cell temperature (in °C): ');
D(6,1)=input('Insert the test cell pressure (in mm Hg): ');
D(7,1)=0;%input('Insert the water temperature at engine entrance (in °C): ');
D(8,1)=0;%input('Insert the oil temperature in (°C): ');
D(9,1)=0;%input('Insert the exhaust gas temperature before turbine (in °C): ');
D(10,1)=0;%input('Insert the exhaust gas temperature behind turbine (in °C): ');
D(11,1)=0;%input('Insert the intake temperature behind intercooler (in °C): ');
D(12,1)=0;%input('Insert the injection pump temperature (in °C): ');
D(13,1)=input('Insert the exit compressor pressure (in mm HG): ');
D(14,1)=0;%input('Insert the turbine entrance pressure (in mm Hg): ');
D(15,1)=0;%input('Insert the turbine exit pressure (in mm Hg): ');
%%% INSERT ALL MATRIX DATA AND FILTER IT %%%
tdc1 = 1477; %[MA,tdc1,tdc2,bdc1] = treat_matrixMA();
tdc2 = 453; %MA1 =(20.48*MA+0.94)*10^5;%(16.58*MA-0.319)*10^5;%;
bdc1 = 1989; %MA = filtering(MA1,5);
[C,sigma] = treat_matrixC(tdc2);
C = (20.48*C+0.94)*10^5; %(16.58*MA-0.319)*10^5;conversion from volt to pascal
C = C+((D(6,1)+D(13,1))*133.3-C(BDC)); %1 mmHG = 1 torr = 133.3 Pa
M = filtering(C,5);
I = treat_matrixI(tdc2,sigma);
I = I*(-1);
I = filtering(I,5);
%The cylinder pressure matrix has to be repositioned regarding the initial
%value in the BDC. This is done by defining the pressure in the BDC as the
%sum of the compressor exit pressure and the test cell pressure. This value
%is then used as the basic pressure for every value in the matrix (see
%Javiers project, page 133).
s = size(M,1); %number of measured points
x = [1:1:s]; %these steps are done to draw the curve later on
y = [1:1:s];
%y = y-TDC; %displazment of the y vector according to TDC
%%% CALCULATING THE LIBERATED HEAT %%%
rpm = D(1,1);
rps = rpm/60;
airfl = D(4,1)*10*sin(pi/6)*1.026e-3; %conversion regla into flow [m^3/s]
densair = (D(6,1)*133.3)/(287.06*(D(5,1)+273.15)); %ro = p/(R*T) [kg/m^3]
masairtot = airfl*densair; %overall air intake
ma = masairtot/(rps*3); %air intake per cycle
for i=1:2047 %%%one starts at 3 because of i-2 in the loop!!!
qdeg = i*deguni;
qdeg = qdeg*pi/180;
vol((i+1),1) = Vc+Apis*r*((1-cos(qdeg))+(1/lambda)*(1-sqrt(1-lambda^2*(sin(qdeg)^2))));
end
vol(1,1) = vol(1025,1);
%%% FOR LOOP TO CALCULATE THE PRESSURE CHANGE %%%
for i=3:2047
IncV(i,1) = (vol(i+1,1)-vol(i-1,1))/2; %increase of cylinder volume
IncP(i,1) = (M(i+1,1)-M(i-1,1))/2; %increase of cylinder pressure
DIncP(i-1,1) = (IncP(i,1)-IncP(i-1,1)); %d/dalpha of IncP
Pinst(i,1) = M(i); %cylinder pressure
V(i,1) = vol(i);
Tg(i,1) = (V(i,1)*M(i,1))/(ma*Rg); %gas temperature in Kelvin
end
%%% HEAT TRANSFER CALCULATION (WOSCHNI) %%%
%IncP=filtering(IncP,2);
MA = M;
for i=800:1700
MA(i,1) = M(800,1)*(vol(800)/vol(i))^1.32;
end
MA((1701:2048),1)=MA(1700,1);
for i=3:2047
Tpis = 250+273.15; %piston temperature in Kelvin
Tcylhea = 200+273.15; %cylinder head temperature in Kelvin
Tcyllin = 200+273.15; %cylinder liner temperature in Kelvin
Tac = Tg(ACr,1); %temperature behind compressor, while admission valve closes [kelvin]
Pac = M(ACr,1); %pressure behind compressor, while admission valve closes [Pa]
Vac = vol(ACr); %volume while admission valve closes [m^3]
Acyllin(i,1) = vol(i)/(Dp/4);%cylinder liner area exposed to the gas
coefC1 = 2.28; %according to Heywood and VKI = Verdichtung,Expansion
w(i,1) = coefC1*(2*ss*rps)+((0.00324*((Vd*Tac)/(Pac*Vac)))*(M(i,1)-MA(i,1))); %[m/s]
alpha(i,1) = 0.013*(Dp^(-0.2))*((M(i,1))^0.8)*((Tg(i,1))^(-0.53))*((w(i,1))^0.8); %[W/m^2K]
% alpha is the heat transfer/film coefficient --> Q = alpha*A*(Ti-Twall)
IncQht(i,1) = (1/(rps*1024))*alpha(i,1)*(Apis*(Tg(i,1)-Tpis)+Ahead*(Tg(i,1)-Tcylhea)+Acyllin(i,1)*(Tg(i,1)-Tcyllin)); %[J/units encode]
end
%%% CALCULATION OF THE INCREMENTAL HEAT REALESE %%%
PdV = (gm/(gm-1))*Pinst.*IncV;
VdP = (1/(gm-1))*V.*IncP;
IncQ = PdV+VdP; %incremental heat released [J/unit]
IncQt = IncQ+IncQht; %total heat realease rate according to vk lecture no. 3
[IncQtT,fppc,fpdc,io,ioo] = TreatIncQ(IncQt,M);
%%% ACUMULATED HEAT Qacum %%%
%Qacum=0;
%for i = 2:size(IncQt,1)
% Qacum(i) = Qacum(i-1)+IncQtT(i);
% i = i+1;
%end
%%% DETERMINING THE IGNITION DELAY %%%
% this is done according to grafic on page 103
% determination of the injection starting point
valueinj = (min(I)+percentinj*max(I));
pinj = 800;
while I(pinj)<valueinj
pinj = pinj+1;
end
% determination of the combustion starting point
deltaQ = max(IncQtT)-min(IncQtT);
valueQ = min(IncQtT)+percent*deltaQ;
plibQ = find(IncQtT==min(IncQtT));
while IncQtT(plibQ)<valueQ
plibQ = plibQ+1;
end
% comparison of the integral of IncQt and the mass of combustible
ENER1 = 0;
for i = 1:1035;
ENER1 = ENER1+IncQt(i); %energy converted during the combustion process
i=i+1;
end
volcom1 = 1/D(3,1); %volume combustible in l/s
volcom2 = volcom1/(rps*3); %volume combustible in liters per cylinder and cycle
mascom1 = volcom2*0.84; %converting volume into mass
ENER2 = mascom1*42800000; %energy J/(cyliner*cycle)
error_energy = 100*(ENER1-ENER2)/ENER2; %error in percent
% calculation of dp/dalpha max
dpmax = max(DIncP);
% calculation of dpmax IncP max of the second combustion phase
IncPmax = max(M)-M(plibQ);
igndel = 1000*(plibQ-pinj)/(1024*rps); %ignition delay in ms
tpremi = 1000*(fppc-plibQ)/(1024*rps); %time premixed combustion in ms
tdifus = 1000*(fpdc-fppc)/(1024*rps); %time difusive combustion in ms
%%% GRAFIX %%%
hold on;
grid on;
Mr = M(884:1308)/1e5;%(M(884:1280)/1.1013e5); %changing the pressure from Pascal to bar
IncQtTr = IncQtT(884:1308);
Ir = I((884:1308));
yr=linspace(-50,100,425);
%yr = (y(884:1280));
%yr = y(998:1139);
[AX,H1,H2] = plotyy(yr,IncQtTr,yr,Mr);
set(H1,'LineStyle','-');
set(H2,'LineStyle',':');
hold on;
H3 = plot(yr,(15*Ir)-2,'r-');
v = [H1,H2,H3];
hh = legend(v,'Released Heat Rate','Pressure Curve', 'Injection Signal',1);
grid off;
xlabel('Crank Shaft Revolutions, Reference TDC [in degrees]');
%set(get(y,'Xlabel'),'String','crank shaft revolutions, reference TDC [in degrees]');
set(get(AX(1),'Ylabel'),'String','Released Heat Rate [Joule/unit]');
set(get(AX(2),'Ylabel'),'String','Cylinder Pressure [bar]');
set(AX(1),'Ylim',[-20 120]);
set(AX(1),'Ytick',[-20 0 20 40 60 80 100 120]);
set(AX(2),'Ylim',[0 140]);
set(AX(2),'Ytick',[0 20 40 60 80 100 120 140]); |
Récupérer des valeurs affichées dans des cases "Edit"
à tous, et un grand bravo aux admin pour tenir un forum aussi agreable a visiter.
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