clear all
close all
clc
% Inputs
gamma = 1.4;
t3 = 2500;
% State variables
p1 = 101325;
t1 = 500;
% Engine geometric parameters
bore = 0.1;
stroke = 0.1;
con_rod = 0.15;
cr = 12;
% Calculation of the swept volume and the clearence volume
v_swept = pi/4*bore^2*stroke;
v_clearance = v_swept/(cr-1);
v1 = v_swept + v_clearance
v2 = v_clearance
% State variables at state point 2
% p1v1^gamma = p2v2^gamma
% p2 = p1*cr^gamma
p2 = p1*cr^gamma
% p1*v1/t1 = p2*v2/t2
% t2 = p2*v2*t1/(p1*v1)
t2 = p2*v2*t1/(p1*v1)
constant_c = p1*v1^gamma;
V_compression = engine_kinematics(bore, stroke, con_rod, cr, 180, 0);
P_compression = constant_c./V_compression.^gamma;
% State variables at stste point 3
v3 = v2
% p2*v2/t2 = p3*v3/t3
% p3 = p2*v2*t3/(v3*t2)
p3 = p2*v2*t3/(v3*t2)
constant_c = p3*v3^gamma;
V_expansion = engine_kinematics(bore, stroke, con_rod, cr, 0, 180);
P_expansion = constant_c./V_expansion.^gamma;
% State variables at state point 4
v4 = v1
% p3v3^gamma = p4v4^gamma
% p4 = p3*(v3/v4)^gamma
p4 = p3*(v3/v4)^gamma
% p3*v3/t3 = p4*v4/t4
% t4 = p4*v4*t3/(p3*v3)
t4 = p4*v4*t3/(p3*v3)
% Thermal Efficiency
thermal_efficiency = 1-(t4-t1)/(t3-t2)
figure(1)
hold on
plot(v1,p1,'*','color','r')
plot(V_compression,P_compression)
plot(v2,p2,'*','color','r')
plot(V_expansion,P_expansion)
plot(v3,p3,'*','color','r')
plot(v4,p4,'*','color','r')
figure(2)
plot([V_compression v2 V_expansion v4 V_compression],[P_compression p2 P_expansion p4 P_compression],'color','b')