1. Diesel Engine Power Plant
Fuel tank
Engine
Generator
Cooling
Tower
Fuel
Pump
Cooling Water
Pump
Air in
Air out

2. Four-Stroke Cycle Engine: An engine that completes one cycle in two
revolutions of the camshaft.
Intake
Compression
Power
Exhaust
intake compression power exhaust

3. Two-Stroke Cycle Engine: An engine that completes one cycle in one
revolution of the camshaft.
Intake & Compression
Power & Exhaust
Exhaust port Exhaust port
Intake port Intake port
Intake & Compression Power & Exhaust

4. Engine Performance
1. Heat Supplied by Fuel (QS)
QS = mF x HV KJ/hr
Where: mf – fuel consumption in kg/hr
HV – heating value of fuel in KJ/kg
KW
4(60)
Nn'LDP
IP
2
miπ
=
2. Indicated Power (IP)
Where: Pmi – indicated mean effective pressure, KPa
L – length of stroke, m
D – diameter of bore, m
N = (RPM)/2 For 4-stroke single acting
N = (RPM) For 4-stroke double acting
N = (RPM) For 2-stroke single acting
N = 2(RPM) For 2-stroke double acting

5. KW
4(60)
Nn'LDP
BP
2
mbπ
=
3. Brake Power (BP)
KW
60,000
TN2
BP
π
=
Where: Pmb – brake mean effective pressure, KPa
L – length of stroke, m
D – diameter of bore, m
N = (RPM)/2 For 4-stroke single acting
N = (RPM) For 4-stroke double acting
N = (RPM) For 2-stroke single acting
N = 2(RPM) For 2-stroke double acting
Where: T – brake torque in N-m
N – no. of (RPM)

6. 4. Friction Power (FP)
FP = IP - BP
5. Indicated Mean Effective Pressure (Pmi)
KPa
L'
SA'
Pmi =
Where: A’ – area of indicator card, cm2
S – spring scale, KPa/cm
L’ – length of indicator card, cm
6. Brake Torque (T)
T = (P – tare)R N-m
Where: P – gross load on scale, N
tare – tare weight, N
R – length of brake arm, m

7. 7. Piston Speed (PS)
PS = 2LN m/min
8. Displacement Volume (VD)
sec
m
P
BP
V
sec
m
P
IP
V
sec
m
4(60)
Nn'LD
V
3
mb
D
3
mi
D
32
D
=
=
π
=
9. Specific Fuel Consumption
a. Indicated Specific fuel consumption
hr-KW
kg
IP
m
m F
fi =

8. b. Brake Specific fuel consumption
hr-KW
kg
BP
m
m F
fb =
c. Combined Specific fuel consumption
hr-KW
kg
GP
m
m F
fc =
Where: GP – Generator power
10. Heat Rate (HR)
a. Indicated Heat Rate (HRi)
hr-KW
KJ
IP
Q
HR S
I =

9. b. Brake Heat Rate (HRb)
hr-KW
KJ
BP
Q
HR S
b =
c. Combined Heat Rate (HRc)
hr-KW
KJ
GP
Q
HR S
c =
11. Generator Speed (N)
RPM
n
120f
=N
Where: n – number of generator poles (usually divisible by 4)

10. 12. Mechanical Efficiency (ηm)
100%x
BP
GP=gη
100%x
IP
BP=mη
13. Generator Efficiency (ηg)
14. Indicated Thermal Efficiency (ei)
100%x
Q
3600(IP)
e
S
i =
15. BrakeThermal Efficiency (eb)
100%x
Q
3600(BP)
e
S
b =

11. 16. Combined Thermal Efficiency (ec)
100%x
Q
3600(GP)
e
S
c =
17. Indicated Engine Efficiency (ηi)
100%x
e
ei
i =η
18. Brake Engine Efficiency (ηb)
100%x
e
eb
b =η
19. Combined Engine Efficiency (ηc)
100%x
e
ec
=η
Where: e – cycle thermal efficiency

12. 20. Volumetric Efficiency (ηv)
100%x
VolumentDisplaceme
ndrawnairofvolumeActual
ηv =
s
h
h
s
sh
T
T
B
B
PP =
21. Correction Factor for Non Standard Condition
 Considering Pressure and Temperature Effects
 Considering Temperature Effects alone
s
h
sh
T
T
PP =

13.  Considering Pressure Effects alone
h
s
sh
B
B
PP =
Note: From US Standard Atmosphere
K
1000
6.5h
-TT
Hgmm
1000
83.312h
BB
sh
sh
°=
−=
Where:
P – power, KW
B – pressure, mm Hg
T – temperature,°K
h – elevation, meters
Subscript:
s – refers to sea level
h – refers to the elevation

14. ENGINE HEAT BALANCE
Qs = Q1 + Q2 + Q3 + Q4
Where:
Q1 – heat converted to useful work
Q2 – heat loss to cooling water
Q3 – heat loss due to exhaust gases
Q4 – heat loss due to friction, radiation and unaccounted for
Q1 = 3600(BP) KJ/hr
Q2 = mwCpw(tw0 – tw1) KJ/hr
Q3 = Qa + Qb
Qa = mgCpg(tg – ta) KJ/hr
Qb = mf(9H2)(2442) KJ/hr
Q4 = Qs – (Q1 + Q2 + Q3) KJ/hr

15. EngineQs
Q2 Q3
Q1
Q4
Qs = Q1 + Q2 + Q3 + Q4 + Q5