In [2]:

```
#Input data
Vs=0.0028 #Swept volume in m**3
N=3000 #Speed of the engine in rpm
ip=12.5 #The average indicated power developed in kW/m**3
nv=85 #Volumetric efficiency in percent
p1=1.013 #The atmospheric pressure in bar
T1=288 #The atmospheric temperature in K
ni=74 #Isentropic efficiency in percent
pr=1.6 #The pressure ratio
nm=78 #All mechanical efficiencies in percent
g=1.4 #Adiabatic index
R=287 #Real gas constant in J/kgK
Cp=1.005 #The specific heat of gas in kJ/kgK
#Calculations
Vs1=(Vs*(N/2.0)) #Volume swept by the piston per minute in m**3/min
Vi=(nv/100.0)*Vs1 #Unsupercharged induced volume in m**3/min
p2=pr*p1 #Blower delivery pressure in bar
T21=T1*(p2/p1)**((g-1)/g) #Temperature after isentropic compression in K
T2=T1+((T21-T1)/((ni/100.0))) #Blower delivery temperature in K
Ve=(Vs1*p2*T1)/(T2*p1) #Equivalent volume at 1.013 bar and 15 degree centigrade in m**3/min
nv1=(Ve/Vs1)*100 #Volumetric efficiency of supercharged engine in percent
Vii=Ve-Vi #Increase in induced volume in m**3/min
ipa=ip*Vii #Increase in ip from air induced in kW
ipi=((p2-p1)*10**5*Vs1)/(60*1000) #Increase in ip due to increased induction pressure in kW
ipt=ipa+ipi #Total increase in ip in kW
bp=ipt*(nm/100.0) #Increase in engine bp in kW
ma=(p2*(Vs1/60.0)*10**5)/(R*T2) #Mass of air delivered per second by blower in kg/s
P=ma*Cp*(T2-T1) #Power input to blower in kW
Pd=P/(nm/100.0) #Power required to drive the blower in kW
bpn=bp-Pd #Net increase in bp in kW
bpu=ip*Vi*(80/100.0) #The bp of unsupercharged engine in kW
bpp=(bpn/(bpu))*100 #Percentage increase in bp in percent
#Output
print"The volumetric efficiency of supercharged engine = ",round(nv1,0),"percent"
print"The increase in brake power by supercharging = ",round(bpn,1)," kW "
print"The percentage increase in brake power = ",round(bpp,1)," percent "
```

In [1]:

```
#Input data
p=1.013 #The pressure at the sea level in bar
T=283 #The temperature at the sea level in K
bp=275.0 #Brake power in kW
N=1800.0 #The speed of the engine in rpm
a=20 #Air fuel ratio
R=287 #The real gas constant in J/kgK
bsfc=0.24 #Brake specific fuel consumption in kg/kWh
nv=80 #Volumetric efficiency in percent
p2=0.75 #The atmospheric pressure at altitude in bar
P=9 #The power consumed by supercharger of the total power produced by the engine in percent
T2=303 #The temperature of air leaving the supercharger in K
#Calculations
mf=(bsfc*bp)/60.0
ma1=mf*a
ma=(2/N)*ma1
dai=(p*10**5)/(R*T)
Vd=(ma/(dai*(nv/100.0)))
pmb=(bp*2*60*1000)/(Vd*N*10**5)
GP=bp/(1-0.09)
ma2=(ma1/bp)*GP
ma1=(ma2*2)/N
p21=((R*T2*ma1)/((nv/100.0)*Vd))/10.0**5
pi=p21-p2
#Output
print"(a) The engine capacity Vd = ",round(Vd,3),"m**3"
print"The bmep of the unsupercharged engine = ",round(pmb,3),"bar"
print"(b) Increase in air pressure required in the supercharged = ",round(pi,3),"bar"
```

In [2]:

```
#Input data
Vs=0.003 #Swept volume in m**3
bmep=9 #Brake mean effective pressure in bar
N=4000 #The speed of the engine in rpm
ni=30.0 #Indicated thermal efficiency in percent
nm=90 #Mechanical efficiency in percent
bmep1=12 #The brake mean effective pressure of other engine in bar
N1=4000 #The speed of other engine in rpm
ni1=25 #The indicated thermal efficiency of other engine in percent
nm1=91 #The mechanical efficiency of other engine in percent
m=200 #The mass of naturally aspired engine in kg
m1=220 #The mass of supercharged engine in kg
CV=44000 #The calorific value of the fuel in kJ/kg
#Calculations
bp=(bmep*10**5*Vs*N)/(2.0*60.0*1000)
ip=bp/(nm/100.0)
mf=(ip)/((ni/100.0)*CV)
bp1=(bmep1*10**5*Vs*N1)/(2.0*60.0*1000)
ip1=bp1/(nm1/100.0)
mf1=ip1/((ni1/100.0)*CV)
mf2=mf*3600
mf3=mf1*3600
x=((200/90.0)-(220/120.0))/((43.2/120.0)-(27.27/90.0))
#Output
print"The maximum hours required for supply of sufficient fuel = ",round(x,3),"hr"
```

In [4]:

```
#Input data
d=0.1 #The diameter of the bore in m
L=0.12 #The length of the stroke in m
N=3000 #The speed of the engine in rpm
n=4 #Number of cylinders
R=287 #Real gas constant in J/kgK
t=120 #Output Torque in Nm
nm=85 #The mechanical efficiency of the engine in percent
T1=288 #The inlet temperature of air into compressor in K
p1=1 #The inlet pressure of air into compressor in bar
Q=1200 #Heat rejected rate in kJ/min
T=328 #The outlet temperature of air in K
p=1.7 #The outlet pressure of air in bar
nv=90 #Volumetric efficiency in percent
Cp=1.005 #Specific heat of gas in kJ/kg
#Calculations
import math
bp=(2*math.pi*N*t)/(60.0*1000.0) #The brake power in kW
ip=bp/(nm/100.0) #The indicated power in kW
pmi=((ip*2*60*1000*4)/(L*(math.pi*d**2)*N*n))/10.0**5 #The mean effective pressure in bar
Vs=(math.pi/4.0)*d**2*L #Swept volume in m**3
Vs1=Vs*(N/2.0)*n #Volume swept by the piston per min
V1=(nv/100.0)*Vs1 #Rate of volume flow of air into the engine in m**3/min
me=((p*10**5*V1)/(R*T))*60 #Rate of mass flow of air into the engine in kg/h
E=Q/60.0 #Energy balance in the after cooling in kJ/s
T2=((bp/E)*T-T1)/((bp/E)-1) #The outlet temperature of air in K
mc=((bp)/(Cp*(T2-T1)))*3600 #Mass flow rate in kg/h
maf=mc-me #Rate of air flow available to the consumer in kg/h
#Output
print"(a) The imep of the supercharged engine = ",round(pmi,3),"bar"
print"(b) The rate of air consumed by the engine = ",round(me,1),"kg/h"
print"(c) The rate of air flow available to the consumer = ",round(maf,1),"kg/h"
```

In [6]:

```
#Input data
Vs=0.0045 #Swept volume in m**3
N=4000.0 #The speed of the engine in rpm
nv=150.0 #Overall volumetric efficiency in percent
ni=90.0 #Isentropic efficiency of the compressor in percent
nm=85.0 #Mechanical efficiency in percent
T=330.0 #The temperature of compressed air after cooler in K
p2=1.8 #The pressure of the compressed air in bar
T1=290.0 #The ambient temperature of air in K
p1=1.0 #The pressure of the ambient condition in bar
R=287.0 #The real gas constant in J/kgK
g=1.4 #Adiabatic index
Cp=1.005 #The specific heat of gas in kJ/kgK
#Calculations
T21=T1*(p2/p1)**((g-1)/g)
T2=T1+((T21-T1)/(ni/100.0))
Vs1=Vs*(N/(2*60)) # m**3/s
Va=(nv/100)*Vs1
d=(p1*10**5)/(R*T1) # kg/m**3
ma=d*Va # kg/s
Q=ma*Cp*(T2-T) # kJ/s
P=ma*Cp*(T2-T1) # kW
Pa=P/(nm/100.0)
#Output
print "(a) The rate of heat rejected from the engine after cooler = ",round(Q,2),"kJ/s"
print"(b) The power absorbed by the supercharger from the engine = ",round(Pa,1),"kW"
```

In [22]:

```
#Input data
p1=0.98 #The inlet pressure of air in bar
T1=290.0 #The inlet temperature of air in K
p2=1.8 #The pressure of air delivered to the engine in bar
a=20.0 #The air fuel ratio
T3=850.0 #The temperature of the exhaust gases leaving the engine in K
p3=1.6 #The pressure of the exhaust gases leaving the engine in bar
p4=1.03 #The turbine exhaust pressure in bar
nc=80.0 #The isentropic efficiency of compressor in percent
nt=85.0 #The isentropic efficiency of turbine in percent
Cpa=1.005 #The specific heat of air in kJ/kgK
Cpg=1.15 #The specific heat of gas in kJ/kgK
g=1.33 #isentropic index
h=1.0 #Adiabatic index
#Calculations
T21=T1*(p2/p1)**(0.286) #value taken in book (g-1/g)=0.286
T2=T1+((T21-T1)/(nc/100.0))
T22=T2-273
T41=T3*(p4/p3)**((g-1)/g)
T4=T3-((nt/100.0)*(T3-T41))
T44=T4-273
mf=1.0 # kg/s
ma=mf*a # kg/s
Wc=ma*Cpa*(T2-T1) # kW
mg=ma+mf #Mass flow rate of gas in kg/s
Wt=mg*Cpg*(T3-T4)
Pt=(Wc/Wt)*100
#Output
print"(a) The temperature of the air leaving the compressor = ",round(T22,0),"degree centigrade"
print"(b) The temperature of gases leaving the turbine = ",round(T44,0),"degree centigrade"
print"(c) The mechanical power used to run the turbocharger = ",round(Pt,1),"percent"
```

In [34]:

```
#Input data
a=14.0 #Air fuel ratio
T1=288 #The ambient temperature of air in K
T2=(288-23) #The evaporation of fuel cause 23 degree C drop in mixture temperature in K
p=1.3 #Pressure ratio
nc=75 #The isentropic efficiency of the compressor in percent
Cpm=1.05 #The specific heat of the mixture in kJ/kgK
Cpa=1.005 #The specific heat of air in kJ/kgK
g=1.33 #Adiabatic index
h=1.4 #Isentropic index
ma=1 #Mass flow rate of air in kg/s
#Calculations
T31=T2*p**((g-1)/g)
T3=T2+((T31-T2)/(nc/100.0))
mm=1+(1/a)
Wc1=mm*Cpm*(T3-T2)
T21=T1*p**((h-1)/h)
T4=T1+((T21-T1)/(nc/100.0))
T4_=317 #approx value taken in book of T4=317
Wc2=ma*Cpa*(T4_-T1)
T5=T4-23
Ps=((Wc2-round(Wc1,0))*100)/Wc2
#Output
print"(a) The power required by the compressor before the supercharger = ",round(Wc1,0),"kW/kg of air per second"
print"(b) The power required by the compressor after the supercharger = ",round(Wc2,1),"kW/kg of air per second"
print"Percentage of turbine power used to run the compressor = ",round(Ps,3),"percent"
```