STUPIDSID
Solve any one question from Q1 and Q2
1 (a)
Draw ideal and actual valve timing diagram (VTD) for four stroke S.I. Engine and state the reason for providing the deviation in timing in actual VTD.
6 M
1 (b)
Draw neat labelled diagram of ideal and actual combustion curve (on P-theta diagram) in S.I. Engines.
6 M
2 (a)
Explain any three from the following losses associated with actual cycle:
i) Time loss
ii) Direct heat loss
iii) Exhaust blow down loss
iv) Pumping loss
v) Rubbing friction loss.
i) Time loss
ii) Direct heat loss
iii) Exhaust blow down loss
iv) Pumping loss
v) Rubbing friction loss.
6 M
2 (b)
Explain the mixture requirements with necessary graphs:
i) For steady state operation
ii) For transient conditions.
i) For steady state operation
ii) For transient conditions.
6 M
Solve any one question from Q3 and Q4
3 (a)
What are the different factors affecting delay period in C.I. Engine?
6 M
3 (b)
A six cylinder petrol engine operates on four-stroke cycle with the following parameters:
Cylinder bore = 70 mm
Piston stroke = 100 mm
Clearance volume per cylinder = 67 cm3
Engine speed = 3960 rpm
Fuel consumption = 19.5 kg/h
Torque developed = 140 N-m
Calculate:
i) The brake power
ii) Brake thermal efficiency if CV of the fuel is 44000 kJ/kg and
iii) The relative efficiency.
Cylinder bore = 70 mm
Piston stroke = 100 mm
Clearance volume per cylinder = 67 cm3
Engine speed = 3960 rpm
Fuel consumption = 19.5 kg/h
Torque developed = 140 N-m
Calculate:
i) The brake power
ii) Brake thermal efficiency if CV of the fuel is 44000 kJ/kg and
iii) The relative efficiency.
6 M
4 (a)
Draw different types of combustion chambers used in C.I. Engines.
6 M
4 (b)
A full load test on a two-stroke engines yielded the following results:
Engine Speed = 450 rev/min,
Brake load = 450 N,
Brake drum diameter = 1.5 m,
Rise in temperature of cooling water 36 deg. C,
Cooling water flow rate = 440 kg/hr
Mass of fuel burnt = 5.4 kg/hr,
Mass of flue gases discharged = 172.8 kg/hr,
Temperature of exhaust gases = 355 deg. C,
Temperature of laboratory = 20 deg.
Engine specification:
Cylinder diameter = 22 cm,
Piston stroke = 27 cm,
CV of fuel = 44000 kJ/kg.
Draw the heat balance sheet for the test on % basis.
Cp for water = 4.18 kJ/kg K,
Cp for flue gases = 1.005 kJ/kg K.
Engine Speed = 450 rev/min,
Brake load = 450 N,
Brake drum diameter = 1.5 m,
Rise in temperature of cooling water 36 deg. C,
Cooling water flow rate = 440 kg/hr
Mass of fuel burnt = 5.4 kg/hr,
Mass of flue gases discharged = 172.8 kg/hr,
Temperature of exhaust gases = 355 deg. C,
Temperature of laboratory = 20 deg.
Engine specification:
Cylinder diameter = 22 cm,
Piston stroke = 27 cm,
CV of fuel = 44000 kJ/kg.
Draw the heat balance sheet for the test on % basis.
Cp for water = 4.18 kJ/kg K,
Cp for flue gases = 1.005 kJ/kg K.
6 M
Solve any one question from Q5 and Q6
5 (a)
Draw neat labelled sketch of battery ignition system showing various components and briefly explain its working.
7 M
5 (b)
Draw neat labelled sketch of Pressurized wet sump lubrication system and in short explain its working and different components lubricated.
6 M
6 (a)
What is the necessity of cooling in I.C. Engines? Explain with neat labelled sketch pressurized thermostatic water cooling system used in engines.
7 M
6 (b)
Explain with neat sketch EGR system for controlling Nox.
6 M
Solve any one question from Q7 and Q8
7 (a)
Explain roots blower compressor with neat sketch.
6 M
7 (b)
A single cylinder air compressor delivers 9 kg of air per minute. The air is compressed from 1 bar and 27 deg. C to 7 bar. The compression process follows the law PV1.25=C. Find
i) Work done,
ii) Brake power required if mechanical efficiency is 85%.
i) Work done,
ii) Brake power required if mechanical efficiency is 85%.
7 M
8 (a)
What are the advantages of multi-staging in reciprocating air compressor.
6 M
8 (b)
During an experiment on a reciprocating air compressor the following observations were made:
Barometer reading = 75.6 cm of Hg, Manometer reading across the orifice = 13 cm of Hg, atmospheric temperature = 25 deg. C, Diameter of orifice = 15 cm, Coefficient of discharge across the orifice = 0.65, Density of Hg=0.0135951 kg/cm3. Determine the volume of free air handled by the compressor.
Barometer reading = 75.6 cm of Hg, Manometer reading across the orifice = 13 cm of Hg, atmospheric temperature = 25 deg. C, Diameter of orifice = 15 cm, Coefficient of discharge across the orifice = 0.65, Density of Hg=0.0135951 kg/cm3. Determine the volume of free air handled by the compressor.
7 M
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