University Of Pune Question Paper
S.E. (Mech.) (Semester – II) Examination, 2011
I.C. ENGINES AND AUTOMOBILE ENGINEERING
(2003 Course)
Time : 3 Hours Max. Marks : 100
Instructions: 1) Answer 3 questions from Section I and 3 questions from
Section II.
2) Answers to the two Sections should be written in separate
books.
3) Neat diagrams must be drawn wherever necessary.
4) Black figures to the right indicate full marks.
5) Use of logarithmic tables slide rule, Mollier charts, electronic
pocket calculator and steam tables is allowed.
6) Assume suitable data, if necessary.
SECTION – I
Unit – 1
1. a) Explain with suitable sketches the working of two stroke engine. 8
b) Explain how actual cycle deviates from theoretical cycles. 4
c) What are the assumptions made in the analysis of fuel air cycle ? 4
OR
2. a) Draw a neat sketch of a four stroke S.I. Engine, label the parts and explain
their functions. 10
b) A Diesel engine has a compression ratio of 20 and cat. off takes place at 5%
of stroke. Find air standard efficiency. 6
Unit – 2
3. a) What are the basic elements of C.I. Engine fuel injection system ? Explain
their functions with schematic diagram. 9
b) What are the functions of carburettor ? Explain any one type of carburettor
with the help of neat sketch. 9
OR
4. a) What is petrol injection ? What are its advantages over carburettor engine ? 6
b) List the types of fuel injectors and explain with a neat sketch working of any
one type of fuel injector. 8
c) What are the air fuel ratio requirements of petrol engine under different loading
conditions ? 4
Unit – 3
5. a) What are the various components to be lubricated in I.C. Engine ? and explain
how it is accomplished. 6
b) What are the harmful effects of overheating of I.C. Engines ? 4
c) Why is governing of I.C. Engines required ? Enlist the methods used for
governing of I.C. engines. 6
OR
6. a) Explain pressure lubrication system. 6
b) Why is spark advance required ? Explain any one spark advance mechanism
with sketch. 6
c) Differentiate between evaporative cooling and forced circulation cooling. 4
SECTION – II
Unit – 4
7. a) What are the various methods of measuring indicated power ? Briefly compare
their relative accuracy. Explain any one method in detail. 8
b) A four stroke four cylinder S.I. Engine has a compression ratio of 8 and bore
of 100 mm with stroke equal to bore. The volumetric efficiency of each cylinder
is equal to 75%. The engine operates at a speed of 4800 rpm with an air fuel
ratio 15. Given that the calorific value of fuel 42 MJ/kg. density of atmospheric
air 1.12 kg/m3
, mean effective pressure in the cylinder is 10 bar and mechanical
efficiency of engine 80%, determine indicated thermal efficiency of the brake
power. 10
OR
8. a) Explain the factors that limits the extent of supercharging in S.I. and C.I.
engine. 8
b) In a trial on a single cylinder oil engine working on duel cycle, the following
observations were made
Compression ratio = 15
Oil consumption = 10.2 kg/h
Calorific value of fuel = 43890 kJ/kg
Air consumption = 3.8 kg/min
Speed = 1900 rpm
Torque on brake drum = 186 N-m
Quantity of cooling water used = 15.5 kg/min
Temperature rise = 36°C
Exhaust gas temperature = 410°C
Room temperature = 20°C
Specific heat of exhaust gas = 1.17 kJ/kg K
Calculate brake power, brake specific fuel consumption, brake thermal
efficiency and heat balance sheet per minute basis. 10
Unit – 5
9. a) Draw the schematic sketch and mention merits and demerits of the following
type of combustion chambers in I.C. Engines.
i) Hemispherical combustion chamber in S.I. engine
ii) M. Combustion chamber in C.I. Engine. 10
b) What is diesel knock ? How dose knocking in a diesel engine differ from
detonation in petrol engine ? 6
OR
v10. a) What are the requirements of good combustion chambers used in S.I. Engine
and C.I. Engines ? 5
b) Discuss the effect of the following engine variables on flame propagation
i) Air fuel ratio
ii) Compression ratio
iii) Load
iv) Speed. 6
c) What is meant by ignition delay in diesel combustion ? Discuss the variables
affecting delay period. 5
Unit – 6
11. a) Discuss in brief the various design and operating parameters responsible for
formation of
i) Carbon monoxide
ii) Hydrocarbons
iii) Oxides of nitrogen in petrol and diesel engine. 6
b) Write short note on : 10
i) Hybrid vehicle
ii) Engine selection (for any application).
OR
12. a) What is smoke ? What are the bad effects of smoke on human health and how
smoke in diesel engine can be controlled ? 6
b) Discuss briefly the following with regard to S.I. Engines :
i) Crank case emission
ii) Evaporative emission
iii) Exhaust emission. 10
—————––––––———
S.E. (Mech.) (Semester – II) Examination, 2011
I.C. ENGINES AND AUTOMOBILE ENGINEERING
(2003 Course)
Time : 3 Hours Max. Marks : 100
Instructions: 1) Answer 3 questions from Section I and 3 questions from
Section II.
2) Answers to the two Sections should be written in separate
books.
3) Neat diagrams must be drawn wherever necessary.
4) Black figures to the right indicate full marks.
5) Use of logarithmic tables slide rule, Mollier charts, electronic
pocket calculator and steam tables is allowed.
6) Assume suitable data, if necessary.
SECTION – I
Unit – 1
1. a) Explain with suitable sketches the working of two stroke engine. 8
b) Explain how actual cycle deviates from theoretical cycles. 4
c) What are the assumptions made in the analysis of fuel air cycle ? 4
OR
2. a) Draw a neat sketch of a four stroke S.I. Engine, label the parts and explain
their functions. 10
b) A Diesel engine has a compression ratio of 20 and cat. off takes place at 5%
of stroke. Find air standard efficiency. 6
Unit – 2
3. a) What are the basic elements of C.I. Engine fuel injection system ? Explain
their functions with schematic diagram. 9
b) What are the functions of carburettor ? Explain any one type of carburettor
with the help of neat sketch. 9
OR
4. a) What is petrol injection ? What are its advantages over carburettor engine ? 6
b) List the types of fuel injectors and explain with a neat sketch working of any
one type of fuel injector. 8
c) What are the air fuel ratio requirements of petrol engine under different loading
conditions ? 4
Unit – 3
5. a) What are the various components to be lubricated in I.C. Engine ? and explain
how it is accomplished. 6
b) What are the harmful effects of overheating of I.C. Engines ? 4
c) Why is governing of I.C. Engines required ? Enlist the methods used for
governing of I.C. engines. 6
OR
6. a) Explain pressure lubrication system. 6
b) Why is spark advance required ? Explain any one spark advance mechanism
with sketch. 6
c) Differentiate between evaporative cooling and forced circulation cooling. 4
SECTION – II
Unit – 4
7. a) What are the various methods of measuring indicated power ? Briefly compare
their relative accuracy. Explain any one method in detail. 8
b) A four stroke four cylinder S.I. Engine has a compression ratio of 8 and bore
of 100 mm with stroke equal to bore. The volumetric efficiency of each cylinder
is equal to 75%. The engine operates at a speed of 4800 rpm with an air fuel
ratio 15. Given that the calorific value of fuel 42 MJ/kg. density of atmospheric
air 1.12 kg/m3
, mean effective pressure in the cylinder is 10 bar and mechanical
efficiency of engine 80%, determine indicated thermal efficiency of the brake
power. 10
OR
8. a) Explain the factors that limits the extent of supercharging in S.I. and C.I.
engine. 8
b) In a trial on a single cylinder oil engine working on duel cycle, the following
observations were made
Compression ratio = 15
Oil consumption = 10.2 kg/h
Calorific value of fuel = 43890 kJ/kg
Air consumption = 3.8 kg/min
Speed = 1900 rpm
Torque on brake drum = 186 N-m
Quantity of cooling water used = 15.5 kg/min
Temperature rise = 36°C
Exhaust gas temperature = 410°C
Room temperature = 20°C
Specific heat of exhaust gas = 1.17 kJ/kg K
Calculate brake power, brake specific fuel consumption, brake thermal
efficiency and heat balance sheet per minute basis. 10
Unit – 5
9. a) Draw the schematic sketch and mention merits and demerits of the following
type of combustion chambers in I.C. Engines.
i) Hemispherical combustion chamber in S.I. engine
ii) M. Combustion chamber in C.I. Engine. 10
b) What is diesel knock ? How dose knocking in a diesel engine differ from
detonation in petrol engine ? 6
OR
v10. a) What are the requirements of good combustion chambers used in S.I. Engine
and C.I. Engines ? 5
b) Discuss the effect of the following engine variables on flame propagation
i) Air fuel ratio
ii) Compression ratio
iii) Load
iv) Speed. 6
c) What is meant by ignition delay in diesel combustion ? Discuss the variables
affecting delay period. 5
Unit – 6
11. a) Discuss in brief the various design and operating parameters responsible for
formation of
i) Carbon monoxide
ii) Hydrocarbons
iii) Oxides of nitrogen in petrol and diesel engine. 6
b) Write short note on : 10
i) Hybrid vehicle
ii) Engine selection (for any application).
OR
12. a) What is smoke ? What are the bad effects of smoke on human health and how
smoke in diesel engine can be controlled ? 6
b) Discuss briefly the following with regard to S.I. Engines :
i) Crank case emission
ii) Evaporative emission
iii) Exhaust emission. 10
—————––––––———
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