An Otto cycle is an idealized thermodynamic cycle that describes the functioning of a typical spark ignition piston engine. It is the thermodynamic cycle most commonly found in automobile engines.this code is to create a PV diagram and calculate the thermal efficiency of the engine.
# Otto Cycle Simulatorimport mathimport matplotlib.pyplot as pltdef engine_kinematics(bore,stroke,can_rod,cr,start_angle,end_angle): """ Engine_Kinematics """ #Engine Parameters a = stroke/2 R = con_rod/a # Volume Computation v_s = (math.pi/4)*pow(bore,2)*stroke v_c = v_s/(cr-1) sc = math.radians(start_angle) # start crank ec = math.radians(end_angle) # end crank num_values = 50 THETA = (ec-sc)/(num_values-1) v = [] for i in range(0,num_values): theta = sc+i*THETA 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#Imputsp1 = 101325t1 = 500gamma = 1.4t3 = 2300# Engine Parametersbore = 0.1stroke = 0.1con_rod = 0.15cr = 8# Volume Computationv_s = (math.pi/4)*pow(bore,2)*strokev_c = v_s/(cr-1)v1 = v_s+v_c# Stage 2v2 = v_c#p1*pow(v1,gamma) = p2*pow(v2,gamma)p2 = p1*pow(v1,gamma)/pow(v2,gamma)# p1v1/t1 = p2v2/t2 | rhs = p1v1/t1 | p2v2/t2 = rhs | t2 = p2v2/rhsrhs = p1*v1/t1t2 = p2*v2/rhsV_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))# Stage 3v3 = v2#P3V3/T3 = P2V2/T2 | rhs = p2v2/t2 | p3v3/t3 = rhs | p3 = rhs*t3/v3rhs = p2*v2/t2p3 = rhs*t3/v3V_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))# Stage 4v4 = v1# p4v4^gamma = p3v3^gamma | p4 = p3v3^gamma/v4^gammap4 = p3*pow(v3,gamma)/pow(v4,gamma)t4 = p4*v4/rhsplt.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()# Thermal Efficiencyn = 1-(pow(cr,(1-gamma)))print(n)