# Chapter 14 : The Diesel Engine¶

## Example 14.1 Page no : 258¶

In :
import math

#Input data
r = 14.3					#Compression ratio
c = 5					#Fuel cutoff in percent of stroke
w = 0.006					#Weight of charge in kg
T4 = 912					#Final temperature in degree C abs
q = 8300					#Heat in kcal
x = [0.258,0.000048]					#Temperature expression is 0.258T+0.000048T**2, where T is in degree C abs

#Calculations
v4 = 1.                       #Assuming clearance volume as unity
v1 = 1.665					#v1 from fig. 14.2 on page no. 352
T1 = (T4*v1)/v4					#Temperature in degree C abs
qp1 = (x*T1+x*T1**2)					#constant pressure heat of mixture at temperature T1 in kcal/kg
qp4 = (x*T4+x*T4**2)					#constant pressure heat of mixture at temperature T4 in kcal/kg
qre = (qp1-qp4)					#Heat required by the mixture in kcal/kg
wf = (w*qre)/q					#Weight of oil in kg

#Output
print 'The weight of oil that must be injected is %3.6f kg'%(wf)

The weight of oil that must be injected is 0.000164 kg


## Example 14.2 Page no : 261¶

In :
import math

#Input data
r = 14					#Compression ratio
p = 1.2					#Induction pipe pressure in kg/cm**2
bp = 0.65					#Exhaust back pressure in kg/cm**2
Tc = 87+273					#Charge temperature in K
Te = 850+273					#Exhaust temperature in K
T1 = 111+273					#Temperature at the beginning of compression in K
g = 1.2					#Ratio of specific heats

#Calculations
Cw1 = ((bp*10**4)/Te)					#specific heat in kJ/kg.K
Cw2 = ((p*10**4*(r-1))/Tc)					#specific heat in kJ/kg.K
T3 = ((g*Te*Cw1+Cw2*Tc)/(Cw1*g+Cw2))					#Temperature in K
t3 = T3-273					#Temperature in degree C
rw = (Cw1/Cw2)					#Ratio of specific heats

#Output
print 'The ratio of the mass residuals to fresh charge is %3.4f'%(rw)

The ratio of the mass residuals to fresh charge is 0.0134