Air standard cycle

# otto cycle simulator

import math
import matplotlib.pyplot as plt

def engine_kinematics(bore,stroke,con_rod,cr,start_crank,end_crank):
# Engine kinametics

#geo. para.
a=stroke/2
R=con_rod/a

# Volume parameters
V_s=math.pi*(1/4)*pow(bore,2)*stroke
V_c=V_s/(cr-1)

sc=math.radians(start_crank)
ec=math.radians(end_crank)

num_values=50
dtheta=(ec-sc)/(num_values-1)

V=[]

for i in range(0,num_values):
theta=sc+i*dtheta
term1=0.5*(cr-1)
term2=R+1-math.cos(theta)
term3=pow(R,2) - pow(math.sin(theta),2)
term3=pow(term3,0.5)
V.append((1+ term1*(term2-term3))*V_c)

return V

# inputs
gamma=1.4
p1=101325
t1=500
t3=2300

#geometric parameters
bore=0.1
stroke=0.1
con_rod=0.15
cr=8

# volume computation
v_s=(math.pi/4)*pow(bore,2)*stroke
v_c=v_s/(cr-1)

#state point 1
v1=v_c+v_s

#state point 2
v2=v_c

#p2v2^gamma=p1v1^gamma
p2=p1*pow(v1,gamma)/pow(v2,gamma)

# p2v2/t2=p1v1/t1 | rhs=p1v1/t1 | p2v2/t2=rhs | t2=p2v2/rhs
rhs=p1*v1/t1
t2=p2*v2/rhs
V_compression=engine_kinematics(bore,stroke,con_rod,cr,180,0)

constant=p1*pow(v1,gamma)

P_compression=[]

for v in V_compression:
P_compression.append(constant/pow(v,gamma))

print(P_compression)

#P_compression*V_compression^gamma=constant
# state point 3
v3=v2

#p3v3/t3=p2v2/t2 | rhs=p2v2/t2 | p3=rhs*t3/v3

rhs=p2*v2/t2
p3=rhs*t3/v3

V_expansion=engine_kinematics(bore,stroke,con_rod,cr,0,180)
constant=p3*pow(v3,gamma)

P_expansion=[]

for v in V_expansion:
P_expansion.append(constant/pow(v,gamma))

# state point 4
v4=v1

#p4v4^gamma=p3v3^gamma
p4=p3*pow(v3,gamma)/pow(v4,gamma)
0

# p4v4/t4=rhs
t4=p4*v4/rhs

plt.plot([v2,v3],[p2,p3])
plt.plot(V_compression,P_compression)
plt.plot(V_expansion,P_expansion)
plt.plot([v4,v1],[p4,p1])
plt.show()

We creating air standard cycle of otto cycle. Shows diffrence strokes due to changing colour from TDC to BDC.