MATLAB FOR MECHANCHIS

1.First of all i create a function named engine_kinematics

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,200);

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

2. now here is my program otto_.m

clear all

close all

clc

gamma = 1.4;

p1=101325;

t1=500;

t3=2300;

bore=0.1;

stroke = 0.1;

con_rod=0.15;

cr=2.2;

v_swept = (pi/4)*bore^2*stroke;

v_clearance = v_swept/(cr-1);

v1 = v_swept + v_clearance;

v2= v_clearance;

p2= p1*(cr^gamma);

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;

v3 = v2;

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;

v4 = v1;

p4 = p3*(v3/v4)^gamma;

figure(1)

hold on;

plot(V_compression, P_compression)

plot(V_expansion,P_expansion)

plot([v2 v3],[p2 p3],\'color\',\'r\')

plot([v4 v1],[p4 p1],\'color\',\'y\')

thermal_efficiency_engine = 1-[(1/cr)^(gamma-1)]