Otto cycle / Air standard cycle

clear all
close all
clc

%input
  gamma=1.4
  t3=2300

%state variables
  p1=101325
  t1=500

%engine geometric parameters
  bore=0.1;
  stroke=0.1;
  con_rod=0.15;
  cr=12;

%calculating the swept volume and clearnce 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
  %p2v2^gamma=p1v1^gamma
  %p2=p1*(v1/v2)^gamma=p1*cr^gamma
  p2=p1*cr^gamma;
  
%p1v1/t1=p2v2/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 variable at state point 3
   v3=v2
  %p3v3/t3=p2v2/t2 | p3=p2*t3/t2
   p3=p2*t3/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 variable at state point 4
 v4=v1
 %p3v3^gamma=p4v4^gamma | p4=p3(v3/v4)^gamma
 p4=p3*(v3/v4)^gamma;
 
      
 figure(1)
 hold on
 plot(v1,p1,'*','color','r')
 plot(V_compression,P_compression)
 plot(v2,p2,'*','color','r')
 plot([v2 v2],[p2 p3])
 plot(v3,p3,'*','color','r')
 plot(V_expansion,P_expansion)
 plot(v4,p4,'*','color','r')
 plot([v1 v4],[p1 p4])