Air standard cycle
In this particular program, I choose Ideal gas equation (assuming atmospheric pressure (p1) and temperature (T1) under the normal condition, the volume (v1) is calculated).
Assuming Compression ratio of 10, we can calculate v2 and be using v1 & v2, p2 can be calculated. T2 can found by the using Isentropic compression equation. T3 (1373K) is already given. Since v3=v2 and v4=v1 so now we have v3 and v4. P3 can be calculated using constant volume heat addition equation. For p4 we will use Isentropic expansion
% Program for Otto cycle
close all
clear all
clc
% v1 calculation use ideal gas equation pv = nRT (n=1)
R = .287
T1 = 308
p1 = 100000
gamma = 1.4
c_r = 10
v1 = R*T1/p1
v2 = v1/7
p2 = (v1/v2)^gamma*p1
T2 = (v1/v2)^(gamma-1)*T1
T3 = 1373
p3 = T3*p2/T2
v3 = v2
v4 = v1
T4 = (v3/v4)^(gamma-1)*T3
p4 = p3*(v3/v4)^gamma
Efficiency = 1-(v2/v1)^(gamma-1)
C = p1*(v1)^gamma
C_1 = p3*(v3)^gamma
% PV Plot
figure(1)
hold on
plot(v1,p1,\'*\',\'color\',\'r\')
plot(v2,p2,\'*\',\'color\',\'g\')
plot(v3,p3,\'*\',\'color\',\'b\')
plot(v4,p4,\'*\',\'color\',\'b\')
% Otto Cycle efficiency
Efficiency = 1-(v2/v1)^(gamma-1)
% For process 2-3 & 4-1
line([v2,v3], [p2,p3],\'linewidth\',1,\'color\',\'r\')
line([v4,v1], [p4,p1],\'linewidth\',1,\'color\',\'r\')
% For process 1-2 & 3-4
line([v2,v1], [p2,p1],\'linewidth\',1.25,\'color\',\'b\')
line([v3,v4], [p3,p4],\'linewidth\',1.25,\'color\',\'b\')