Download PTU. I.K. Gujral Punjab Technical University (IKGPTU) M.Tech Mech Eng 3rd Semester 38222 ADVANCED INTERNAL COMBUSTION ENGINES Question Paper.
Roll No. Total No. of Pages : 03
Total No. of Questions : 08
M.Tech.(ME) (Sem.?3)
ADVANCED INTERNAL COMBUSTION ENGINES
Subject Code : MME-559
M.Code : 38222
Time : 3 Hrs. Max. Marks : 100
INSTRUCTION TO CANDIDATES :
1. Attempt any FIVE questions out of EIGHT questions.
2. Each question carries TWENTY marks.
3. Assume any data missing.
Q.l. a) The two-stroke cycle has twice as many power strokes per crank revolution as the four-
stroke cycle. However, two-stroke cycle engine power outputs per unit displaced
volume are less than twice the power output of an equivalent four-stroke cycle engine
at the same engine speed. Suggest reasons why this potential advantage of the two-
stroke cycle is offset in practice.
b) List five important differences between the design and operating characteristics of
spark-ignition and compression-ignition engines.
Q.2. a) Two automobile engines have the same total displacement volume and the same total
power produced within the cylinders. List the possible advantages of :
(i) A V6 over a straight six.
(ii) A V8 over a V6.
(iii) A V6 over a V8.
(iv) An opposed cylinder four over a straight four.
(v) An in-line six over an in-line four.
b) The Wankel rotary spark-ignition engine, while lighter and more compact than a
reciprocating: spark-ignition engine of equal maximum power typically has worse
efficiency due to significantly higher gas leakage from the combustion chamber and
higher total heat loss from the hot combustion gases to the chamber walls. Based on the
design details suggest reasons for these higher losses.
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1 | M-38222 (S9)-400
Roll No. Total No. of Pages : 03
Total No. of Questions : 08
M.Tech.(ME) (Sem.?3)
ADVANCED INTERNAL COMBUSTION ENGINES
Subject Code : MME-559
M.Code : 38222
Time : 3 Hrs. Max. Marks : 100
INSTRUCTION TO CANDIDATES :
1. Attempt any FIVE questions out of EIGHT questions.
2. Each question carries TWENTY marks.
3. Assume any data missing.
Q.l. a) The two-stroke cycle has twice as many power strokes per crank revolution as the four-
stroke cycle. However, two-stroke cycle engine power outputs per unit displaced
volume are less than twice the power output of an equivalent four-stroke cycle engine
at the same engine speed. Suggest reasons why this potential advantage of the two-
stroke cycle is offset in practice.
b) List five important differences between the design and operating characteristics of
spark-ignition and compression-ignition engines.
Q.2. a) Two automobile engines have the same total displacement volume and the same total
power produced within the cylinders. List the possible advantages of :
(i) A V6 over a straight six.
(ii) A V8 over a V6.
(iii) A V6 over a V8.
(iv) An opposed cylinder four over a straight four.
(v) An in-line six over an in-line four.
b) The Wankel rotary spark-ignition engine, while lighter and more compact than a
reciprocating: spark-ignition engine of equal maximum power typically has worse
efficiency due to significantly higher gas leakage from the combustion chamber and
higher total heat loss from the hot combustion gases to the chamber walls. Based on the
design details suggest reasons for these higher losses.
2 | M-38222 (S9)-400
Q.3. Design a six-liter race car engine that operates on a four-stroke cycle. Decide what the
design speed will be, and then give the number of cylinders, bore, stroke, piston rod length,
average piston speed, imep, brake torque, fuel used, AF, and brake power, all at design
speed. All parameter values should be within typical, reasonable values and should be
consistent with the other values. State what assumptions you make (e.g., mechanical
efficiency, volumetric efficiency, etc.)
Q.4. Cylinder conditions at the start of compression of a four-stroke cycle SI engine are 27?C
and 100 kPa. The engine has a compression ratio of r
c
= 8:1, and heat addition from
combustion is q
in
= 2000 kj/kg. Calculate :
a) Temperature and pressure at each state of the cycle, using air-standard Otto cycle
analysis with constant specific heats.
b) Indicated thermal efficiency in part (a).
c) Temperature and pressure at each state of the cycle, using any standard air tables which
are based on variable specific heats as functions of temperature
d) Indicated thermal efficiency in part (c).
Q.5. C4Hs is burned in an engine with a fuel-rich air-fuel ratio. Dry analysis of the exhaust
gives the following volume percents: COz = 14.95%, C4Hs = 0.75%, CO = 0%, Hz = 0%,
Oz = 0%, with the rest being Nz. Higher heating value of this fuel is Q
HHV
= 46.9 MJ/kg.
Write the balanced chemical equation for one mole of this fuel at these conditions.
Calculate:
a) Air-fuel ratio.
b) Equivalence ratio.
c) Lower heating value of fuel.
d) Energy released when one kg of this fuel is burned in the engine with a combustion
efficiency of 98%.
Q.6. Design a fuel intake system for a large dual-fuel CI engine to be used in a poor
underdeveloped country. The engine is to use only enough diesel oil to promote
ignition, while using some less costly main fuel. Draw a schematic, and give engine
values of displacement, speed, and volumetric efficiency. Choose an appropriate main
fuel and give the flow rates of both fuels. What is the overall air-fuel ratio? State all
assumptions you make.
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1 | M-38222 (S9)-400
Roll No. Total No. of Pages : 03
Total No. of Questions : 08
M.Tech.(ME) (Sem.?3)
ADVANCED INTERNAL COMBUSTION ENGINES
Subject Code : MME-559
M.Code : 38222
Time : 3 Hrs. Max. Marks : 100
INSTRUCTION TO CANDIDATES :
1. Attempt any FIVE questions out of EIGHT questions.
2. Each question carries TWENTY marks.
3. Assume any data missing.
Q.l. a) The two-stroke cycle has twice as many power strokes per crank revolution as the four-
stroke cycle. However, two-stroke cycle engine power outputs per unit displaced
volume are less than twice the power output of an equivalent four-stroke cycle engine
at the same engine speed. Suggest reasons why this potential advantage of the two-
stroke cycle is offset in practice.
b) List five important differences between the design and operating characteristics of
spark-ignition and compression-ignition engines.
Q.2. a) Two automobile engines have the same total displacement volume and the same total
power produced within the cylinders. List the possible advantages of :
(i) A V6 over a straight six.
(ii) A V8 over a V6.
(iii) A V6 over a V8.
(iv) An opposed cylinder four over a straight four.
(v) An in-line six over an in-line four.
b) The Wankel rotary spark-ignition engine, while lighter and more compact than a
reciprocating: spark-ignition engine of equal maximum power typically has worse
efficiency due to significantly higher gas leakage from the combustion chamber and
higher total heat loss from the hot combustion gases to the chamber walls. Based on the
design details suggest reasons for these higher losses.
2 | M-38222 (S9)-400
Q.3. Design a six-liter race car engine that operates on a four-stroke cycle. Decide what the
design speed will be, and then give the number of cylinders, bore, stroke, piston rod length,
average piston speed, imep, brake torque, fuel used, AF, and brake power, all at design
speed. All parameter values should be within typical, reasonable values and should be
consistent with the other values. State what assumptions you make (e.g., mechanical
efficiency, volumetric efficiency, etc.)
Q.4. Cylinder conditions at the start of compression of a four-stroke cycle SI engine are 27?C
and 100 kPa. The engine has a compression ratio of r
c
= 8:1, and heat addition from
combustion is q
in
= 2000 kj/kg. Calculate :
a) Temperature and pressure at each state of the cycle, using air-standard Otto cycle
analysis with constant specific heats.
b) Indicated thermal efficiency in part (a).
c) Temperature and pressure at each state of the cycle, using any standard air tables which
are based on variable specific heats as functions of temperature
d) Indicated thermal efficiency in part (c).
Q.5. C4Hs is burned in an engine with a fuel-rich air-fuel ratio. Dry analysis of the exhaust
gives the following volume percents: COz = 14.95%, C4Hs = 0.75%, CO = 0%, Hz = 0%,
Oz = 0%, with the rest being Nz. Higher heating value of this fuel is Q
HHV
= 46.9 MJ/kg.
Write the balanced chemical equation for one mole of this fuel at these conditions.
Calculate:
a) Air-fuel ratio.
b) Equivalence ratio.
c) Lower heating value of fuel.
d) Energy released when one kg of this fuel is burned in the engine with a combustion
efficiency of 98%.
Q.6. Design a fuel intake system for a large dual-fuel CI engine to be used in a poor
underdeveloped country. The engine is to use only enough diesel oil to promote
ignition, while using some less costly main fuel. Draw a schematic, and give engine
values of displacement, speed, and volumetric efficiency. Choose an appropriate main
fuel and give the flow rates of both fuels. What is the overall air-fuel ratio? State all
assumptions you make.
3 | M-38222 (S9)-400
Q.7. a) Explain why constant-volume combustion gives a higher indicated fuel
conversion efficiency than constant-pressure combustion for the same compression
ratio.
b) Estimate approximately the pressure drop across the inlet valve about halfway
through the intake stroke and across the exhaust valve halfway through the exhaust
stroke, when the piston speed is at its maximum for a typical four- stroke cycle
spark-ignition engine with B = L = 85 mm at 2500 and 5000 rev/min at WOT.
Assume appropriate values for any valve and port geometric details required, and
for the gas composition and state.
Q.8. Write short notes on :
a) Turbocharger
b) Kadney effect
c) Scavenging
d) Supercharging
NOTE : Disclosure of Identity by writing Mobile No. or Making of passing request on any
page of Answer Sheet will lead to UMC against the Student.
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This post was last modified on 13 December 2019