)uthern Technical Universitv

Subject: I C engines
asrah Technical Engg College
Date :,;t / l1 tZOtl
rel and Energy Techniques Dept. tFC|/\dit Ilrt::tl lCiil
Time: 3 Hour
First Examinat ion /Z0l 6-2017

Answer five questions and each one holds equal marks

Ql:Comparison of Otto, diesel and Dual cycles: Equal compression Ratio andFqual
Heat added

Q2; A two stroke diesel engine was motored when the meter reading was
1.5 kw.Then
the test on the engine was carried out for one hour
and the following observations
were recorded: Brake torque :
l20,Nm; Speed: 600 rpm; Fuel used: 2.5 kg;calorific
value of fuel :
40.3 MJ/kg; cooling water used :
ats'tg; nir. temperature of i.
cooling water :
lOoC.Exhaust gas temperature 345oC. :i"-perature nio- :
25oc;
A/F - 32: l.
Determine :

(i) bp,
(ii) ip,
(iii) Mechanical effi ciency,
(iv) Indicated thermal efficiency, and
(v) Draw heat balance sheet on minute basis and
also'in percentage.

03:Expain briefly

A-Algnition and Flame Development in SI engine.

B:Flame Propagation in S1 Engines.

Q4: Derive thermal efficiency for the dual cycle engines: Explain p-V and T-S
diagram.

l) External combustion engines have a lower thermal efficiency than the Internal
combustion engines.?

2) The compression temperature in S.I. engines should

be lower than (S.I.T.) of the
fuel.?
 3) The compression temperature in C .I. engines should be higher than (S.I.T.) of the
fuel.?

4) The compression ratio is limited in S.I. engines.?

5) The power products from 2 stroke engine is greator than the power products from
4
stroke engine.?

6) Thermal efficien cy of 2 stroke engine is less than that for 4 stroke engine.?

7)Two stroke engine is not popular.?

8) In 2 stroke engine thermal stresses are more.?

Q6:: A four stroke engine with six cylinder,clearance volume for each cylinder
300cm3,runs at speed 3500 rpm and compression ratio 10:1 .The out put power is 100
kW at above speed. If the engine operates with both otto and diesel cycle, with same
heat added and the pressure and temperature at the start 1 bar and 15 oC. Assume brake
thermal effrciency equal to thermal efficiency.
Compare between otto and diesel cycle engine conesponding the following:
1-Thermal efficiency.
2-The amount of heat added to each cylinder.
3-The work done from each cylinder.
4- The mean effective pressure.

EOOD LUCK

vr
.uxamlner \\"*J of S+
Dr S.F Al-bahadilli
Dr. N *iA l'".NS.
 Southem Technical University STU Subject: I C engines
Basrah Technical Engg College BETC Date :06 I l8 12017
Fuel and Energy Techniques Dept. ;FCtir{Aiatt ltiiil 1t'01
Time: 3 Hours
\her fu :iNrin*'ttlri.rl ('olhir/
First Examinat ion 120 | 6-20 17

NOTE: Answer only five questions and each one holds equal marks.

Ql:
l-What is the different between Heat engine and Heat pump?-Write an equation for each one
and define each symbols?.
2-What is the different between actual and theoretical relation between piston and valves(valve
timing) explain with help of diagram?.
3- What are the main consideration factors for the air-fuel cvcles?.

Q2: An air-standard dual cycle has a compression ratio of 12. At the beginning of compression,
Pr is 100 kPa andTt is 335 K. The maximum pressure is 52.17 bar. Cut-off ratio t.OtS.
Calculate:
a-The temperatures at cardinal points.
b-The cycle efficiency.
c-The mean effective pressure of the cycle

Q3: A simple jet carburetor is required to supply 3 kg of air per minute and,0.2 kg per minute
of fuel density 70 kglm3. The air is initially at 1.013 bar and 30'C . Calculate the throat
diameter of the choke for an air flow velocity of 70mls.Take the velocity coefficient for the
venture to be 0.80 and the coefficient of discharge of the main fuel jet to be 0.6. Assume
isotropic flow and the flow to be compressible. If the pressure drop across the fuel metering
orifice is 0.75 of that the stroke. Calculate the orifige dbrqglgr . Take: Cp:1.00d kJ/kg.K , Cv
:0.8 kJ/kg.K

Q4: Answer only one:

A:What are the CI engine combustion stages. Explain the first stage with diagram.

B: Give a suitable reason for the following statements:

l-Swirl motion is an important effect in designing air manifold and valve.
2-Engine air manifold hold equal distance for each engine cylinder.
3- The height of the nozzle exit above the level of the fuel in the float chamber (Z) ls an
important of the carburetor design factor.

4- Increasing or decreasing the test pressure injector is unacceptable.

5- The loss of volumetric efficiency is the main disadvantage of the carburetor system
 , )|

Q5: A 1500 cm3 ,four stroke cycle, four cylinder CI engines operating at 3000 rpm and
produces 48 kW. Volumeterc efficiency is 0.92, air fuel ratio is 2l: I and mechanical
efficiency is 0.85. Calculate:
i-Rate of air flow into engine.[kg/s]
ii-Brake specific fuel consumption.[g/kw .h]
iii-Mass rate of exhuste gases flow.[kg/h]
iv-Indicated power. tkWl.

Q6: The following observations were made during a test on an oil engine:
Brake power:30 kW
Fuel used=l0 kgltrr
Calorific value of fuel:42000kJ/kg
Jacket circulation water 9 kg/min
Rise in temperate of cooling water:60 "C
The exhaust gases are passes through the calorimeter :
\hter circulated through exhaust gas calorimeter: 9.5 kg/min
Rise temperature of water passing through the exhaust gas calorimeter:40 "C
Temperature of exhaust gases leaving the calorimeter: g0 "c
Air /fuel ratio on mass basis :20
Ambient temp:17 "6
Mean s specific heat of exhaust gases:l.0 kJ&g.K
Specific heat 0f water:4.l8k/kgK
Draw up the engine heat balance sheet on (( kw)) and percentage basis.

Good Luck
,,4184 //4/4,\-
Examiner Head of Dep
Dr Saadoon Albahadili Dr Amjad Ahmad
 Subject: I C engines
Southern Technical Universify
Technical Eng. College/Basra silfrc
;JqJ!,iiyaj,r, | :,gi;it i$,lt
Date : 05 / 19 12016
Fuel and Energy Engineering Dept. B$r. t:rylRdflg l.cislrl f lnllagt Time: 3 Hour
First Examination /2015-2016

Answer All Ouestions and each one holds equal mark (20 mark)

Q1: Answer only tow(l0mark for each one)

l-Classifu the internal combustion engines according to , ( .\

Working cycle-ignition-cooling-air intake- piston movement.
thermodynamic cycle.

2-Explaine briefly with diagram the relation between the ignition lag(ms)
and mixture strength (%).

3- What are the main functions of the diesel fuel injection system.

Q2:-A fuel mixture of 460/o CzHrs by volume is used in an engine having a

bore [20 mm and stroke length of 145 mm. The compression ratio is 8.5.
The percentage composition of dry product of combustion by volrtme is
CO2: l2o , CO:l .5%o, 02:25% and the rest is N2. Calculate the air-fuel
ratio and mass of the residual gases left in the cylinder at the end of the
exhaust stroke if the pressure and temperature are 1 . I bar and 720 K.

Q3-The compression ratio of an ideal cycle is 6 and the pressure and

temperature at the beginning of compression stroke are lbar and 40 oC
respectively. The maximum pressure in the cycle is 34.3 bar. For I kg of air
flow calculate the ratio of heat supplied to heat rejected. Power is required
without combustion is 8kW at engine speed 1000 rpm. Find th'e other
engine power if mechanical effrciency is 7|o/o.Take R:287 JlkgK

Q4-Answer only two: (lOmark for each one)

briefly with drawing the difference between actual and theoretical

1- Explain
combustion through the relation between the cylinder'pressure and cranck
angle rotation.
 for Sl engines'
2-Classify and drawing the modern combustion chambers

3-Comparission of knocking between SI & CI

engines'

Q5-An in-line six cylinder, 3.3-liter

cI engine using light diesel fuel at an
Dual cycle' Half the fuel
airfuel ratio of AF - 15 operates on an air-standard
at constant pressure
can be considered burned at constant volume, and half
pressure in the cycle is 60
with combustion efficiency lo0%. The maximum
are 60"C and 101 kPa'
bar. Cylinder conditions at the start of compression
compression ratio rc
: l4;1. Fuel consumption is 5 kg/hr at 4000 rym'
Calculate:

(a) Temperature at each state of the cycle' [K]

(b) Pressure at each state of the cycle' [kPa]

(c) Cutoff ratio.

(d) Pressure ratio"

(e) Thermal efficiency. l%l

(f) Heat added during combustion process' [kJlkg]

(f) Volumetric efficiencY [%]

GOOD LUCK

ftrfrhAoh'
Examiner
Head of DePartment

Dr Amjad Ahmed
Dr Sadoun Albahadili
 cif..1rJl4{114.+
Southern Technical University Subject: IC engines
Technical Engg College/Basrah Sffirc Date:16 ll/2016
Fuel and Energy Techniques Dept Time: 2 Hour
I't season exam /2015-2016

Ql: Answer only two: (-25 mark)

A: What is the main reason for the following statements:
valves' timing -. spark ignition timing- helical slots into manifold- using turbocharger
-exhaust valve location near spark plug.

B: Define only five : swept volume - compression ratio - Knocking - valves timing-

overlap valves angle -pre ignition.

C: Explane with the drawing graph the following:
i-The equivalence ratio on the exhaust gases.
ii- Pressure variation with the crank angle rotation for SI engines.
Q2:Answer only one: (25 mark)
-
A An ideal Diesel engine has a diameter of 15 cm and stroke 20 cm. The clearance
volume is 10 percent of swept volume. Determine the compression ratio and the air
standard effrciently of engine if the cut offtakes place at 6 percent of the skoke.
B- Gasoline having an average chemical formula (C8 Hl7) is bumed in an engine at a
fuel air ration of (0.08).
i- write the chemical reaction equation.
ii-calculate the fraction of (C) burned to (CO).
iii-write the final balanced chemical reaction equation.
Q3- An IC engine operating on the dual cycle,(Tl:27 C), the ratio of the max and min
pressures is (70), and compression ratio is (15), the amount of heat added at constant
volume and at constant pressure are equal. Compute the air standard thermal efficiency
of the cycle. (25 mark)
Q4:Answer only one: (25 mark)
1-List the factors effecting the ignition Lag at SI engines combustion.
Z-T\e following factors affect the Knocking in an engine.
i-Composition of the fuel.

v
ii-Engine design factor
iii-Time factor
Explain each factor briefly.
GOOD LUCK
fluaa
' -bxamlner I Hfad of Department
Dr SADOTJN ALBAHADILI DT AMJAD AHMED
t2, 1. Zot6
Foundation of Technical Education
Subject: IC ENGINES
Technical College/Basra
Date : l9 l20ls
Fuel and Energy Engineering Dept
Time: 3 Hours
Stage : Third year
Second Attempt l20l4A0$

Answer all questions

Ql: Answer only one : (20 mark)
A: List only three advantage and disadvantage points for the
two stroke engines .
B:List the difference between the actual and afuel-air
cycle. Explain the losses on the p-v
diagram for CI engines.

Q2: (20 mark)

A: A hydrocarbon fuel has the following composition of dry products
of combustion bv thea
volume.
COz:l2oh , CO:0.5%o , O2:4o/oand the rest Nz
Determine the airlfuel ratio, the percent theoretic al air and the percentage composition of
fuel on the mass basis.
B. How to perform following tests:
1-Morse test.

2-William's line test.

3-Motoring test.

^
Q3: Answer only two: (20 mark)
A: what is the electronic fuel injection system?, Explain briefly
only one type.
B: Described with help of diagram the swirl combustion chamber
in CI engines.
C: Discuss the effect of the following factors on the combustion
process of SI engines.
*Load *spark plug location

TA&fi TIIE Pt4.6E

Q4: Answer only two. (40 mark)
A: A four stroke engine with six cylinder, swept volume for each cylinder 300cm3,runs at
speed 3500 rpm and compression ratio 10:l.The output power is 100 kW at above speed. If
the engine operates with both otto and diesel cycle, with same heat added, and the pressure
and temperature at the start I bar and 15 oC respectively. Assume brake thermal efficiency
equal to thermal effrciency. Compare between otto and diesel cycle engine corresponding the
following:
l-Thermal efficiency.
2-The amount of heat added to each cylinder.

3-The work done from each cylinder.

4- The mean effective pressure.

B- A six-cylinder 4-stroke cycle petrol engine is to be designed to develop 300 kW of (b.p)

at2500 rpm the bore / stroke ratio is to be l:1.25. Assuming mechanical efficiency:83%o
and an indicated mean effective pressure of 9.5 bar, determine the required bore and stroke.
If the compression ratio of the engine is to be 6.5 to l, determine consumption of petrol in
kg/h and in ke/bp.hr. Take the indicated thermal efficiency of the engine is 28.9% and the
calorific value of the petrol as;44770kJlkg.

C- A single cylinder, 4-stroke diesel engine running at 1800 rpm has a bore of 85 mm and a
stroke of 1 10 mm. It takes 0.56 kg of air per minute and develops a brake power output of 6
kW while the air fuel ratio is 20 : 1. The calorific value of the fuel used is 42550 kJ/kg and
the ambient air density is 1.18 kg/m3 at T:300K, R:287 J/kg.K. Calculate:
(1) The volumetric efficiency.
(2) Brake specific fuel consumption.

GOOD LUCK

Examiner Head of department

Dr. Sadoun Fahad Dr. Amjed Ahmed

 \

Southern Technical University Subject: IC ENGINES

Technical Engg College/Basra Date z7l 6l20tS
Fuel and Energy Engineering Dept. Time: 3 Hours
Class : third year 1't Attempt Examination 2014-20Ls

Answer all questions

Q1: Answer only one.(18 mark) \

A-From figure below derive relation between piston displacement and crank angle.

Crank Pin

Crank Shaft Piston Pin

B- A Diesel engine at atmospheric conditions has a compression ratio of 20 and a

peak temperature of 3000K. Using an Air Standard cycle analysis, estimate the
work per unit mass of air, the cutoff ratio, the combustion pressure, and thermal
efficiency.

Q2: An eight-cylinder four-stroke-cycle engine has a bore of 10 cm and a stroke of

12 cm. At a shaft speed of 53 rps, the brake power is 300kW and the mechanical
efficiency is 85%. Fuel with a heating value of 40,000 kJ/kg is supplied at a rate of
40 kglhr. What are the engine performance, BMEP, torque, Friction power and
indicated specific fuel consumption in kglkW-hr? (20 mark)
 t

Q3: Briefly answer only three :(7 mark for each one)
l-What are the most important methods for measuring the friction power and
explain only one.
2- At a high engine speed is the valves angle increased or decreased and why?

3- Compare between types of Air- Fuel Cycle.

4- Compare between Otto, diesel and Dual Cycles at equal compression ratio and
heat rejected.

Q4: Briefly answer only three: (7 mark for each one)

l- Draw and discuss the relation between the equivalence ratio and engine speed.
2-Draw and describe the spray pattern when fuel is injected into swirling air .

Show a plot of equivalent ratio on the on the spray pattern.

3- Explain with diagram the effect of ignition delay on the diesel knock.
4-compare between normal, abnormal, pre-ignition respectively.

Q5: A test carried out on a single cylinder, two stroke engine working at initial
conditions 300K and lbar gave the following data:
Cylinder bore 200 mm, stroke250mm, engine speed 300rpm, net Rake torque 500
N.m, indicate mean effective pressure 4.9*106 N/m2, Fuel consumption 5 kglmin,
temperature rise of cooling water 55K water mass floy*0.055 kg/s and Specific
fe1 o.f exhaul gases:1.0 kJlkg.K at 550K Calculate: #: Mechanicat efficiency.
b: brake specific fuel consumption. t:draw up an energy balance in kw..

(20 mark)

GOOD LUCK

fu)f,1/K/-,
/ Examlner Head of department
Dr S.F Albahadili Dr Amjed Ahmed
Southern Technical UniversitY Subject: IC ENGINEI
Technical Engg College/Basra Date : l8/412015
Fuel and Energy Engineering DePt. Time: 2 Hours
Class : third year 2nd Examination 2'014-201!

Answer all questions

Ql: 30 mark

1-For the figure below define each symbol and word.

o-
o
L
f
ut
v,
o
o-

--Negative
- Work i
i

540
BDC
Crank Angle, I (degreos)

2-Explain briefly the phenomena of the Flame Propagation in sl Engines

3-What is the effect of air fuel ratio on the flame speed?

Q2:Answer only three: 30 mark

l-List only the factors effecting the ignitionLagat SI engines combustion'

2-The following factors effect the octane requirements of an engine.

(a) Composition of the fuel

(b) Cornbustion charnber geornetry
(c) Charge motion

Explain each factor brieflY.

Turn the page
 3-comparison of knock between SI engines and cI engines.

4--Described with help of diagram the Ricardo swirl chamber

.

Q3: The diameter of venturi throat and fuel nozzle of a carburettor are (gcm
&5
mm) respectively. The coefficients of discharge for air
anf fuel are (0.9 & 0.7)
respectively. The air and fuel densities are (1.3 & 700)k/m3
respectively. The
fuel level in the float chamber is (5 mm) below the throat,
and the pressure at the
throat is (96%) of the ambient pressure. Neglecting the effect of air
compressibility, calculate airlfuel ratio when:
1-The nozzle level lip is neglected
2- The nozzle lip is taken into account .
(15 mark)

Q4: A single cylinder, 4-stroke diesel engine running at 1800 rpm has a bore
of g5
mm and a stroke of 110 mm. It takes 0.56 kg of air per
minute and develops a
brake power output of 6 kw while the air fuel ratio
is 20 : l. The calorific value of
the fuel used is 42550 kJkg and the ambient air
density is llB kg/m3. calculate:
(a) The volumetric efficiency and (b) Brake specific
fuel consumption (c) Brake
thermal efficiency.
(25 mark)

6AOD LUCK

\Wltac4
_\r
Examiner
/)nn/U o
Head of Department
/6 . q. Zois /J/^.(\<.p2"
 ./'-
P'siruttrern Technical University
Subject: IC ENGINES
Technical Engg Coltege/Basra
Fuel and Energy Engineering Dept.
Date : l0 lll}Lts
Time:2 Hours
class : third year
First Examina tion ZAl -Z}ls

ma
#: List onlv two advantage and disadvantage points for the two stroke engines .

il: Explain onlv with diasramthe actual and theritecal

combustion stages for sI engines.

#: A hydrocarbon fuel has the foll.owing composition of dry products of

CO2:l2Yo , CO:OSYo , O2:4yo *a th. iest N2 combustion by the volume.
Determine the airlfuel ratio, the percent theoretical
air and the percentage composition of fuel zr
mass basis.

ff: Prove that thermal efficiency of diesel engine as:

(a)uEsel = I - (t/r,)*-t[(pk - t)/lk(p - I)l]
where: rc : compression ratio
k: cpfco
6 = cutoff ratio

*tAtt in-line six cylinder, 3.3-liter cI engine using light diesel fuel
rperates on an air-standard Dual cycle. at an air-fuel ratio of AF : 2(
Half the fuel can be consideied burned at constant
ralf at constant pressure with combustion volume, anc
;ompression are 30oc and l0l
efficiency 100%. cylinder conditions at the start o
kpa. compression
a) Temperature at each state of the
,xio rr: rr'r'
l4:1. \'orvur'lL'
calculate:
b\res11e at each state of the cycle.
cycte. Jt<1
J '
c, -utoffratio. tkpuj
C) Pressure ratio.
:) Thermal efficien cy. l%l
[) Heat added during combustion process.
tkJ/kg]

:Give a suitabre reason for five

of the foilowing statements
-The compression temperature
in s.l. enginei should be lower than start
;.1.T.) of the fuel. of ignite temperature
-ln 2 stroke engine
a deflected crown piston is used.
-Turbocharger is limited
in Sl engine.
'swirl motion is important effect in
designing air maniford s"v
and varve.
YC'rvs
'Maximum combustion pressure
'Valves overrap angre is an
occurs ATDC
important engine specification.
 c:
r--+t' \ ).
!-

diagrams'
,rDiscuss briefly the following

I
!
I
thoichlornctric
--
I
I
I
I
I
I

l,
tc
an
o
e
-9
l!

Rlch
1# I
Laan

n
n 12 14
Alr-Fusl Ratlo

tfl
I
tr,l
l

rt
l0
I
f
n * ^
I
trffiTt Ln t,* rs

GOOD LUCK

^)A
l(,'{(-<-f
WAltv/'-\\,, Head of DePa#ent
r-.-
{
 Foundation of Technical Education Subject: IC ENGINES
Tech nical College/Basra
Date.zlT /6/2014
' Fuel.and Energy Engineering Dept. Time: 3 Hours
Stage : third year Final Examina tion /2013-Z0l 4

Answer all questions

Ql:20 mark
A: List only three advantage and disadvantage points for the two stroke engines
.

B:List the difference between the actual and a fuel-air cycle. Explain the p-V diaerar
losses on the
fbr CI engines.

Q2:20 mark
A' - ' hydrocarbon fuel has the following composition of dry products of combustion
by the volume.
CO2:l2o/o , CO:OSYo , O2:4Yo and the rest N2
Determine the airlfuel ratio, the percent theoretical air and the percentage
composition of fuel on thr
rlass basis.
B: Explain with help of diagram the effect of ignition delay on the rate pressure
of rise and knockinl
in a diesel ensines

Q3:(30 mark)
A: What is the electronic fuel injection system?, Explain briefly only
one type.
Bacribed with help of diagram the swirl combustion chamber in CI engines.
C:Discuss the effect of the following factors on the combustion process of
SI engines.
xLoad *spark plug location

Q4:Answer only two.(30 mark)

A: A four stroke engine with six cylinder,gfv€,ptvolume for each cylinder 300cmr,runs at
speed
-a
3500 rpm and compression ratio 10:1.The output power is 100 kW at above
speed. If the engine
operates with both otto and diesei eyele, with same heat added, and the pressure
and temperature at
nthegae-*:bar"ed15 -@respe:t'i'plg*Asnrnretnake $retrhf,t"6ffici-en*ilt
fr i:pd1'to theffidfcffi:i$fi6y:T'"
Corn-parebetweenottoanddieselcycleenginecorTespondin-gth9fouowing;

TURTI TTTE PA6E

 z-Thermal efficiency.
{
2-The amount of heat added to each cvlinder.
3-The work done from each cvlinder.

1:. Ih en gpp_ .e_ffegl iy gp1ge 9yre.

B- A six-cylinder 4-stroke cycle petrol engine is to be designed to develop 300 kW of (b.p) at 250
rpm the bore / stroke ratio is to be I:1.25. Assuming mechanical efficiency:83%o and an indicate
mean effective pressure of 9.5 bar, determine the required bore and stroke. If the compression rati
of the engine is to be 6.5 to l, determine consumption of petrol in keltr and in kg/bp.hr. Take th
indicated thermal efficiency of the engine rs 28.9o/o and the calorific value of the petrol al
44770k1/kg.

C- A single cylinder,4-stroke diesel engine running at 1800 rpm has a bore of 85 mm and u rl..
I l0 mrn. It takes 0.56 kg of air per rninute and develops a brake power output of 6 kW while the a

fuel ratio is 20 : l. The calorific value of the fuel used is 42550 kJ/kg and the ambient air density i
l.l8 kg/m3 at T:300K, R:287 Jlkg.K. Calculate:
(l) The volumetric efficiency .
(2) Brake specific fuel consumption.

GOOD LUCK

4nHooL)
Examiner Head of department

Dr Sadoun Fahad Dr Mohammed Hassan

i
':i -l
 \
Southern Technical Coltege Subject: I C engines
Technical College/Basra Date z 12 l4l20l4
(Fuel and Energy- ) Engg
Time: 2 Hour
Techniques Dept. and
z"- semester exam /2015-2016

glilr 4li-,Yl e^.J4-+Jrl!

e-,Jy _y alL)l
ec.Uill
CJ^+ r.,c' LLyl _ \ stl.:\

Q1: Briefly give two reasons of the following (answer only five).(25 mark)
l-Using more than fuel filters for diesel system.
2-Preignition combustion chamber is used.
3- Fuel cut off is very important in diesel engines.
4-Rich mixture is prepared at low engine speed.
S-Direct fuel injection is used for gasoline engines.
6- using plenum chamber in the modern air maniford.

Q2:(30 mark)
A:Classi$ the direct injection systems for SI engines and explain only
one
with drawing.
B:Compare between direct injection and carburetion with help by
drawing.

a
Q3:(a5 mark)
A:Explain the effect of air swirl on the fuel spray.
B:Explain the effect of ignition delay on the diesel Knock. ,

C: Explain briefly the state of the following fuel injection plunger position.
 Elor*oor of Sndsf
lr-5ke dd-rvcr3t
IrlNuiransr dafiecrt/
tr)

End.f 8cOoslsf,
$'ok doti*ry rtra|c.
frlcrrd 6.1ir.4,
{r}
&sedgfir-r'
('G) n

GOOD LUCK

r' {t: ) l,4rL, n

DO\4INAR

lo'v. .,'i/
- _r\l
 2)
\)
-.-eF

cilyll l,UJ€ ?

Foundation of Technical Education Subject: IC ENGINES

Technical College/Basra
Fuel and Energy Techniques Dept.
@
NOTE: answer only five questions and each one holds equal mark
Date zltg tzDtl
Time: 3 Hour
Final Exam ination /2012-2013
2nd attempt

Ql: Answer only two

A: Distinguish between spark ignition and compression ignition engines .
B: Define: heat pump- compression ratio - Knocking - valves timing- stratified charge

engine - Dynamometer.
C: Derive an expression to evaluate thermal efficiency, using compression ratio, pressure
ratio and cut off ratio.

Q2:
A: Methane is burned with 100/o excess air. Determine the stoichiometric airlfuel ratio and
the actual airlfuel ratio. If the air is supplied at I bar and27 oC, calculate the volume of air

supplied per kmole of fuel. Determine the molecular weight of the reactants and products.
Take: R"i,: 8314 kJlkmol.K.
B:A three liter SI V6 engine operates on a four stroke cycle at 3000 rpm. The compression
ratio is 9.0 the length of the connecting rode is 17.2 cm and the engine is square. At this
speed combustion ends at20o aTDC. Determine:

l-The average piston speed. .

2-The clearance volume of one cylinder.

3-The piston speed at the end of combustion.
4-The distance the piston travels from TDC at the end of combustion.
5-The volume in the combustion chamber at the end of combustion.

Q3:Answer only two:

A: Explain with help of the P-V diagram and the typical port timing for the two stroke
engines.

B: Give a comparative statement of the various factors to be decreased or increased, which

tend to reduce knock in SI and CI engines and explain only one factor.

C:What do you understand by a stratified charge engine?

Q4: A simple jet carburetor is required to supply 3 kg of air per minute and 0.2 kg per
minute of fuel density 70kglm3. The air is initially at 1.013 bar and 30oC . Calculate the
throat diameter of the choke-foe an air flow velocity of 70mls.Take the velocity coefficient
for the venture to be 0.80 and the coefficient of discharge of the main fuel jet to be 0.6.
Assume isotropic flow and the flow to be compressible. If the pressure drop across the fuel
metering orifice is 0.75 of that the stroke. Calculate the orifice diameter . Take: Cp:1005
kJ/kg.K , Cv:0.8 kJ/ke.K

Q5:Answer only two:

A: What are the advantages of the spherical combustion chamber? Describe with the help of
diagram.
B: Give the classifications of different types of fuel injector of a CI engines. Explain only
one from these injector.
C: : What are the basic requirements of a good SI engines combustion chamber and explain
the main advantages of the over head valve combustion chamber.
D: Compare the Otto, Diesel and limited pressure cycles for the same compression ratio and
same heat input.

Q6:A six-cylinder, gasoline engine operates on the four-stroke cycle. The bore of each
cylinder is 80 mm and the stroke is 100 mm. The clearance volume per cylinder is 70 cc. At
the speed of 4100 rpm, the fuel consumption is 5.5 gm/sec.[or 19.8 kdhr.) and the torque
developed is 160 Nm.
Calculate : (i) Brake power, (ii) The brake mean effective pressure, (iii) Brake thermal
efficiency if the calorific value of the fuel is 44000 kJ/kg and (iv) The re-lative efficiency on
abrakepowerbasisassumingtheengineworksonth.ryyde-r:|.4forair.

An,/)
l)t /UUz-.--
T/ \-/l I GOOD LUCK

Examiner Head of department

 dlt.;*ll
i:-Jc ?

Foundation of Technical Education Subject: IC ENGINES

Technical College/Basra
Fuel and Energy Techniques I)ePt.
@
NOTE: answer onlv five questions and each one holds equal mark
Date z l 6l20l3
Time: 3 Hour
Final Examina tion 12012-20\3
-i
2"" attempt

Ql: Answer only two

A: Distinguish between spark ignition and compression ignition engines .

B: Define: heat pump- compression ratio - Knocking - valves timing- stratified charge
engine - Dynamometer.
C: Derive an expression to evaluate thermal efficiency, using compression ratio, pressure
io and cut off ratio.

A: Methane is burned with 100/o excess air. Determine the stoichiometric airlfuel ratio and
oC, calculate the volume of air
the actual airlfuel ratio. If the air is supplied at 1 bar and 27
supplied per kmole of fuel. Determine the molecular weight of the reactants and products.
Take: Rui, : 8314 kJ&mol.K.

B:A three liter SI V6 engine operates on a four stroke cycle at 3000 rpm. The compression
ratio is 9.0 the length of the connecting rode is 17.2 cm and the engine is square. At this
speed combustion ends at20o aTDC. Determine:

1-The average piston speed.

Z-The clearance volume of one cylinder.

3-The piston speed at the end of combustion.

4-The distance the piston travels from TDC at the end of combustion'
5-The volume in the combustion chamber at the end of combustion'

Q3:Answer only two:

A: Explain with help of the P-V diagram and the typical port timing for the two stroke
engines.
which
B: Give a comparative statement of the various factors to be decreased or increased,
tend to reduce knock in SI and CI engines and explain only one factor.

C:What do you understand by a stratified charge engine?

 Q4: A simple jet carburetor is required to supply 3 kg of air per minute and 0.2 kg per
minute of fuel density 70 k{m3. The air is initially at 1.013 bar and 30oC . Calculate the
throat diameter of the choke foe an air flow velocity of 70mls.Take the velocity coefficient
for the venture to be 0.80 and the coefficient of discharge of the main fuel jet to be 0.6.
Assume isotropic flow and the flow to be compressible. If the pressure drop across the fuel
metering orifice is 0.75 of that the stroke. Calculate the orifice diameter . Take: Cp:1005
kJ/kg.K , Cv:0.8 kJ/kg.K

Q5:Answer only two:

A: What are the advantages of the spherical combustion chamber? Describe with the help of
diagram.
: Give the classifications of different types of fuel injector of a CI engines. Explain only
I one from these injector.
I C: What are the basic requirements of a good SI engines combustion chamber and explain
tl

Io ttre main advantages of the over head valve combustion chamber.

.le Otto, T)iesel cycles for the Isame compressio: n ratio and
! D: Compare the Otto and limited nressrrre
Diesel nnd pressure cvcles

Il same heat input.

ll qO'e six-cylinder, gasoline engine operates on the four-stroke cycle. The bore of each
I cylinder is 80 mm and the stroke is 100 mm. The clearance volume per cylinder is 70 cc. At
I tne speed of 4100 rpm, the fuel consumption is 5.5 gm/sec.for 19.8 kgAr.) and the torque
I developed is 160 Nm.
ll Calculate : (i) Brake power, (ii) The brake mean effective pressure, (iii) Brake thermal
I efficiency if the calorific value of the fuel is 44000 kJlkg and (iv) The relative efficiency on
ft brake power basis assuming the engine works on the constant volume cycle r:
L4 for air.

GOOD LUCK

/)rnrt /(uaLl
Examiner Head of department

2-q - zot 3
 Foundation of Technical Education Subject: IC ENGINES
Tech nical Coltege/Basra Date t22 l6l20tg
f,'uel and Energy Engineering Dept. Time: 3 Hours
Stage : third year Finat Examina tion 12012-2013

Answer onlv four questions. and each one holds equal mark

Ql:Give a suitable one reason for ten from the following statements.
l-The compression temperature in S.I. engines should be lower than start of ignite temperatur
(S.I.T.) of the tuel.
2- The compression temperature in CI engines should be higher than (S.I.T).

3- Use more than fuel filter before the fuel injection pump.

4-In2 stroke engine a deflected crown piston is used.

)r{urbssharger is limited in SI engine.

6-Engine lubricating oil must be changed every 3000 km.

7-Swirl motion is important effect in designing air manifold and valve.

8- Maximum combustion pressure occurs with a suitable ATDC .

9-The compression ratio is limited in S.I. engines.?

10-The power products from 2 stroke engine is greater than the power products from 4 strokt
engine.?

11-Thermal efficiency of 2 stroke engine is less than that for 4 stroke engine.?

Q2:
4:$ftat are the basic requirements of a good CI engines combustion chamber ? explain with help o
c. rram only one of these combustion chambers.
B: A fuel oil CnHza is burned with30oA excess air .Determine:
The equivalence ratio, volumetric analysis of the products of combustion in percentage. Molecular
weight of products and reactants, if air at 15 oC and pressure is I bar.

Q3:
A: A four stroke engine with six cylinder,clearance volume for each cylinder 300cm3,runs at speec
3500 rpm and compression ratio 10:1.The out put power is 100 kW at above speed. If the engine
operates with both otto and diesel cycle, with same heat added and the pressure and temperature a
the start 1 bar and 15 oC. Assume brake thermal efficiency equal to thermal efficiency.
Compare between otto and diesel cycle engine corresponding the following:
l-Thermal efficiency.
2-The amount of heat added to each cylinder.
3-The work done from each cylinder.
4- The mean effective pressure.
B: Compare the Otto, Diesel and limited pressure cycles for the same compression ratio and same
heat input o
1_1
 Q4:
A: Explain briefly the state of the following fuel injection plunger a,d and c position.

Botaorn ef hd af
|t0{.G del*+cry
li{sirr,rrrrn dcl ilcl1r
(r)

€f
E}rlrtrran
$rolcr
,Eert *.lir*1r
{€,

B:A four cvlinder SI engine has a bore of 60mm and stroke of 85

o! Z, mm. It runs at 3000 rpm witt
torque arm'35m'The brake load is 160 N and fuel consumption
is 6.6 L/hr. The specific gravity ol
fuel is 0'78 and it has a lower colorific value of 44000kJ/kg.
A mores test is carried out and the
cylinders are cut out in the order 1,2,3,4 with conesponding
brake loads of 114,110,1 l2,and. 116
respectively' Calculate bmep, brake thermal efficiency,
mechanical effrciency and Imep .

Q5:Answer only three:

l-Explaine the phenomenon of diesel knock. Compare
it with the phenomenon of detonation^ rn SI
engines.

2-:What is ignition lag? Discus the effect of engine variables

on this stage .
3-A:What are the advantages of the overhead valve combustion
chamber? Describe with the help of
diagram the operation mechanism of this valve.

4-Draw and discus tn-e valve timing angle for the two
stroke engines.
GOOD LUCK

,€),{#Hu<}
Dr sadoun Albahadili
Dr alaaAlderawi
2-2
Foundation of Technical Education Subject: IC engines
Technicat Coltege/Basrah Date :415 12013
Fuel and Energy Techniques Dept. Time: 2 Hour
Final Examinat ion l20tl2-2013
2nd attempt
NOTE: answer all questions
Ql:Answer only one (20 mark)
A: Classif'the different types of an electronic injection system for SI engines .
Explain each one with help of a diagram. :
B: Describe the construction and working of the Bosch injection pump elements?

Q2:Answer only one: (20 mark)

A: what are the requirements of a fuel injection system of a cI engines?
B What are the advantage and disadvantage of the SI engine fuel injection system?

Q3: (30 mark)

A: What are the different type of CI engine nozzles? Explain with help of a diagram
of only one .
B: Give a suitable reason for the following statements: '

l-Swirl motion is an important effect in designing air manifold and valve.

2-Engine air manifold hold equal distance for each engine cylinder.

3- The height of the nozzle exit above the level of the fuel in the float chamber (Z)
is
an important of the carburetor design factor .

4- Increasing or decreasing the test pressure injector is unacceptable.

5- The loss of volumetric efficiency is the main disadvantage of the carburetor

system

Q4: The following observations were made during a test on an oil engine:
Brake power:30 kW

Fuel used:l0 kglhr

Calorific value of fuel:42000kJlkg

Jacket circulation water: g kg/fu

(2-r)
 :i '
.;-- l''''' '':l ': '

.' ,.. .: : ..,. 't."-tt

,: '_ :t:
.,r: r . :,, r .,, : ,, r ..:.l. ,

Riseinrempe'fi&.of.cooling.wdtElF60.oC.-..-.....'.'.
The exhaust'$4g9,s are passet *"ough,thq,catmim"to;,I:r.' '.''. ; ". '

Water cirsulated through exhaust gas caloiimeter

, ' r.' 1 . ,
: 9.5 kg/min
Rise temperature of water passing through the exhaust gas calorimeter:40 "C
oc
Temper3ture of exhaust gases leaving the calorimeter: 80
1-. ::'

Air /fuel ratio on mass basis :20 ' :

Ambient temp:l7 oC

Mean s specific heat of exhaust gases:l.0 kJ/kg.K

Specific heat 0f water4.18kJ/kgK

kw)) (30 mark)
Draw up a heat balance sheet on (( and percentage basis.

GOOD LUCK

head of dePartment

DT SADOUN AL-BAHADILI DT ALAA AL-DERAWI

L?,'q'La|3

(2-2)
 dlJJl i:uJGF
crlilJl dlJlryl drls:rr..c 3lrt cJl
sjijll #lrjltai+r
Otiet*, :iJ"Jl o;r.q -@lijsJl
&lt3l ;' ;' t1
i.lLhJl3 t$Jll g,r.. rr i*"ril ;-.itt
2013 /l/ 23 g,;.lEtt 2013 -2012 s'.,,lJJl ftrlJ &yl di,a.iJl 0r-rll
as. .1r 25 dlS*
dsl., 4!-,yf 6r.+ Cf i+l

1- What are the differences between the analysis of the air- standard cycle and
that of the fuel air cycle?
2- Explain how to measure the engine friction power.

3- Explain with drawing a sketch of pistons inside the cylinders with valves for
the six cylinder engine, if the piston at the first cylinder at i5 d.gr.. after
top dead
center. Take firing order 153624

!: Petrol ,four stroke engine with six cylinders, cylinder diameter is 75 mm and
stroke length is 90 mm runs at 2000 rpm. During the test the following observations
were made:
Engine torque 150N.m, engine torque when cut out spark from each cylinder is
120N.m, fuel consumption 12.2 Kglhl air consumption 138Kg/hr, fuel hlat value
44000KJAQ at initial operation condition 25 oc and i bar: calcui-ate:
Thermal, mechanical and volumetric efficiency.

I, A fuel oil cnHza is burned with2}%excess air.Determine:

The equivalence ratio, volumetric analysis of the products of combustion in
percentage. Molecular weight of product and reactance .

ItAt, oil engine operating on oC

a dual cycle has a compression ratio of 15 and
compression begins at I bar, 30 . The maximum pressure reached is 70 bar. The
heat transferred to air at constant pressure is equal to that at constant volume.
Determine the pressure and temperature at cardinal points of the cycle
,the cycle
efficiency.

GOOD LUCK
n
,tbnk? ,19 , A1
-r-

UW' Head of Dep

Dr Saadoon Albahadili Dr Alaa Alderawi