PV Diagram Visualizer for OTTO cycle

Piston Kinematics

function [v] = pistonkinematics(bore,stroke,cr_rod,cr,startcrank,endcrank)

cradius = stroke/2; R = cr_od/cradius;

%calculating the swept volume and clearance volume

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

v_clearance = v_swept/(cr-1);

theta = linspace(startcrank,endcrank,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_clearance;

endfunction

Otto cycle

 

%Otto Cycle 

clear all

close all

clc

%static variables

p1=202650;

t1=300;

t3=3000;

gamma=1.3;

%engine parameters

bore=0.3;

stroke=0.15;

cr_rod=0.15;

cr=13;

%calculations

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

clearv=sweptv/(cr-1);

v1=sweptv + clearv;

v2=clearv;

p2=p1 * cr^gamma;

t2=(p2 * v2 * t1)/(p1 * v1);

v3=v2;p3=(p2 * v2 * t3)/(v3 * t2);

v4=v1;

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

t4=(p4 * v4 * t3)/(p3 * v3);

constant1=p1*v1^gamma;

v_comp=pistonkinematics(bore,stroke,cr_rod,cr,180,0);

p_comp=constant1./v_comp.^gamma;

constant2=p3 * v3^gamma;

v_exp=pistonkinematics(bore,stroke,cr_rod,cr,0,180);

p_exp=constant2./v_exp.^gamma;

figure(1)

hold on;

plot(v1,p1,'color','r');

plot(v_comp,p_comp);

plot(v2,p2,'color','r');

plot([v2 v3],[p2 p3]);

plot(v3,p3,'color','r');

plot(v_exp,p_exp);

plot(v4,p4,'color','r');

plot([v4 v1],[p4 p1]);

ylabel('pressure');

xlabel('volume');

%calculate Efficency

n=(1-cr^(1-gamma))*100;

fprintf("Efficency = %d" ,n)

PV DIAGRAM