otto cycle

clear all
close all
clc
% inputs
gamma=1.4
% state variables
p1=101325
t1=500
t3=2300
% engine parameters
bore=0.1;
stroke=0.1;
con_rod=0.15;
cr=12;
% calculating the swept volume and the clearance volume
v_swept=(p1/4)*bore^2*stroke;
v_clearance=v_swept/(cr-1);
v1=v_swept+v_clearance
v2=v_clearance
a=stroke/2;
theta=linspace(0,360,100);
% state variables at the state points2
% p2v2^gamma = p1v1^gamma
% p2= p1*(v1/v2)^gamma
p2=p1*cr^gamma
% p1v1/t1=p2v2/t2
t2=p2*v2*t1/(p1*v1)
% calculating compression volume
term1=0.5*(cr-1);
term2=a+(1-cosd(theta));
term3=(a^2-(sind(theta)).^2).^(0.5);
v_compression=(1+term1*(term2-term3))*v_clearance
c=p2*v2^gamma;
p_compression=c./(v_compression).^gamma
% state variables at the state point 3
v3=v2
% p3v3/t3=p2v2/t2
p3=p2*t3/t2
% calculating expansion

v_expansion=(1+term1*(term2-term3))*v_clearance
c1=p3*v3^gamma;
p_expansion=c1./(v_expansion).^gamma

%state varibles at state point 4
v4=v1
% p3v3^gamma=p4v4^gamma
p4=p3*(v3/v4)^gamma
%p4v4/t4=p1v1/t1
t4=p4*t1/p1
% calculating the thermal efficiency
efficiency=1-(1/((cr)^(gamma-1)))
figure(1)
hold on
plot([ v_compression v_expansion ],[ p_compression p_expansion ])
plot([v2 v3],[p2 p3])
plot([v4 v1],[p4 p1])