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Free download in PDF Marine Engineers Multiple Choice Questions and Answers for competitive exams. These short objective type questions with answers are very important for Board exams as well as competitive exams. These short solved questions or quizzes are provided by Gkseries.
(1)
Which standards govern the specifications for supply of Residual Marine Fuels and Distillate Marine Fuels onboard merchant ships?
[A]
ISO 3012:1999
[B]
ISO 3648:1996
[C]
ISO 8216-1:2010
[D]
ISO 8217:2010
(2)
Crank web deflection readings will give a positive indication of
[A]
worn main bearing journals
[B]
torsional stress deformation
[C]
slack thrust bearings
[D]
bearing shells shim dimensions
Answer: worn main bearing journals
(3)
Which of the following is an example of a solid bearing?
[A]
Piston pin bushing
[B]
Turbo-generator turbine bearing
[C]
Spring bearing
[D]
Thrust bearing
Answer: Piston pin bushing
(4)
In comparison to exhaust valves, intake valves of diesel engines may be fabricated from low-alloy steels because
[A]
the beveled edges of the intake valves provide forself-centering during seating
[B]
intake valves utilize stellite-coated valve seat inserts which reduce wear
[C]
the volume of air passing through intake valves is less than the volume of air passing through exhaust valves
[D]
intake valves are less affected to the corrosive action of exhaust gases
Answer: intake valves are less affected to the corrosive action of exhaust gases
(5)
Why is it essential to renew turbocharger bearings after a preset number of hours of running even if the bearings are in seemingly perfect condition?
[A]
Because they are prone to failure due to prolonged exposure to high temperature conditions.
[B]
Because they are subject to cyclic loading and are prone to failure due to metal fatigue.
[C]
It is not essential to renew if condition monitoring suggests perfect condition.
[D]
Lube oil contamination is bound to occur and affect the condition of the bearings.
Answer: Because they are subject to cyclic loading and are prone to failure due to metal fatigue.
(6)
Modern marine turbochargers use a ___________ type of compressor
[A]
Radial flow
[B]
Axial flow
[C]
Mixed flow
[D]
Turbulent flow
(7)
Which of the following is a disadvantage of water as cooling medium for pistons, when compared to oil?
[A]
Chemical treatment is required
[B]
Higher thermal stresses in piston
[C]
Piston of more complicated design
[D]
All of the above
(8)
In a 2-stroke marine diesel engine if the o-ring for Jacket cooling water sealing is leaking then
[A]
The water will leak directly into the crankcase
[B]
The water will leak into the under piston space
[C]
The water will come out through tell-tale hole provided between the two o-rings
[D]
The water will come out from the top of cylinder jacket
Answer: The water will come out through tell-tale hole provided between the two o-rings
(9)
The lube oil pump used in a diesel engine is a
[A]
volute pump
[B]
centrifugal pump
[C]
diaphragm pump
[D]
gear pump
(10)
The coating which is provided on the valve stem of exhaust valves of modern marine diesel engines is of:
[A]
Nickel
[B]
Stellite
[C]
Chromium
[D]
Nimonic
(11)
Which of the following statements is true, about slow speed engines?
[A]
A scavenge fire can lead to a crankcase explosion
[B]
A scavenge fire can lead to deformation of diaphragm plate
[C]
A scavenge fire can lead to damage to tie rods.
[D]
All of the above
(12)
For a two stroke engine two o-rings are provided on the liner. The function of the top oring is to ___________ and function of the lower o-ring is to ____________
[A]
Seal jacket cooling water; act as secondary seal in case 1st o-ring leaks
[B]
Seal jacket cooling water, Seal scavenge air
[C]
Seal scavenge air, Seal Jacket cooling water
[D]
Seal combustion gases, Seal jacket cooling water
Answer: Seal jacket cooling water, Seal scavenge air
(13)
Even if there is an oil mist concentration inside a crankcase, and there is also a hot spot,crankcase explosion will only take place when
[A]
The hot spot provides the ignition temperature for the oil mist concentration
[B]
When the oil mist - air mixture is in the flammable range
[C]
Both A and B
[D]
None of the above
(14)
Some 4-stroke engines are fitted with a rotorcap on the cylinder head valves. For what reason?
[A]
Rotate the inlet valve during operation.
[B]
Distribute the exhaust gas or the air inlet better to improve combustion.
[C]
Improve the scaling surface function, increase the service time of the exhaust valve in the engine
[D]
To prevent the valve spindle from sticking
Answer: Improve the scaling surface function, increase the service time of the exhaust valve in the engine
(15)
A large, low-speed, main propulsion diesel engine uses sea water to directly cool the
[A]
cylinder heads
[B]
exhaust valves
[C]
scavenging air
[D]
injectors
(16)
Exhaust Grouping is required in case of ______________ turbocharging in order to
[A]
constant pressure, prevents shockwave generation
[B]
pulse pressure, prevent interference with scavenging of other cylinders
[C]
constant pressure, prevent interference with scavenging of other cylinders
[D]
pulse pressure, prevents shockwave generation
Answer: pulse pressure, prevent interference with scavenging of other cylinders
(17)
After prolonged operation, jerk type fuel pumps wear on the top edge of plunger and edges of spill ports and helix due to erosion by high pressure fuel as it spills. This wear
would result in
[A]
Late start of injection and early end of injection
[B]
Early start of injection and late end of injection
[C]
Early start of injection and early end of injection
[D]
Late start of injection and late end of injection
Answer: Late start of injection and early end of injection
(18)
Labyrinth seal fitted on the back surface of a compressor wheel of a turbocharger:
[A]
Prevents bearing lube oil contamination
[B]
Prevents bearing lube oil being sucked into the air stream
[C]
Helps to keep the shaft cool by controlled leakage of air
[D]
None of the above
Answer: Helps to keep the shaft cool by controlled leakage of air
(19)
It is a known fact that centrifugal pumps require priming for pumping liquids, as they cannot handle air and will lose suction due to air entry. But on the other hand T/Cs use centrifugal compressors for supercharging. Which of the following do you think makes a centrifugal compressor to pump air and behave differently than the centrifugal pumps?
[A]
Presence of air cooler
[B]
Presence of Labyrinth seal
[C]
High speed of rotation, very fine internal clearances and large impeller diameters
[D]
Difference in principle of operation
Answer: High speed of rotation, very fine internal clearances and large impeller diameters
(20)
Which of these fuel oil impurities can cause maximum abrasive damage?
[A]
Water
[B]
Ash
[C]
Catalytic fines
[D]
Sodium
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