PV N THERMAL EFFICIENCY OF OTTO CYCLE

THERMAl efficiency= 0.6299

%code%

%function%

function [v] = engine_kinematics(bore, stroke, con_rod, cr, start_crank, end_crank)

a=stroke/2
R=con_rod/a

v_s=pi/4*bore^2*stroke;
v_c=v_s/(cr-1);

theta = linspace(start_crank,end_crank,100);

term1=0.5*(cr-1);
term2=R+1 -cosd(theta);
term3=(R^2-sind(theta).^2).^0.5;

v=(1+ term1*(term2 - term3)).*v_c;

end

%program for pv n thermal efficiency

clear all
close all
clc
%inputs
gamma=1.4
t3=2300

%state variables
p1 =101325
t1 =500

% ENGINE GEOMETRIC PARAMETERS
bore =0.1;
stroke=0.2;
con_rod=0.26;
cr=12;
%calculating the swept volume and clearance 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
p2=p1*cr*gamma;
t2=p2*v2*t1/(p1*v1);
v_comp=engine_kinematics(bore, stroke, con_rod,cr,180,0);
constant_c=p1*v1*gamma;

p_comp=constant_c./v_comp.^gamma;

%state 3
v3=v2
p3=p2*t3/t2
v_exp=engine_kinematics(bore, stroke, con_rod,cr,0,180);
constant_c=p3*v3*gamma;

p_exp=constant_c./v_exp.^gamma;

% state 4
v4=v1
p4=p3*(v3/v4)^gamma

figure(1)
hold on
plot(v1,p1,\'color\',\'r\')
plot(v_comp,p_comp,\'color\',\'r\')
plot(v_exp,p_exp,\'color\',\'r\')
plot(v4,p4,\'color\',\'r\')
plot([v_comp v_exp],[p_comp p_exp],\'color\',\'r\')
plot([v_exp v4],[p_exp p4],\'color\',\'r\')
xlabel(\'Volume->\')
ylabel(\'Pressure->\')

%thermal eff
te=1- 1/(cr)^(gamma-1);