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Free download in PDF Marine Engineers MCQs 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.
81
Working of a pulse pressure turbocharger depends upon the ___________ that can be safely created in the exhaust system.
[A]
Enthalpy drop
[B]
Pressure difference
[C]
Turbocharger rpm
[D]
Pressure pulses
82
The maximum elongation of timing chains in service is limited to ___________ of original chain length.
[A]
2%
[B]
1%
[C]
5%
[D]
3%
83
Routine cleaning of air side of air cooler of main engine is done by:
[A]
Circulating fresh water
[B]
Circulating cold chemical solution
[C]
Circulating warm chemical solution
[D]
Circulating hot water
Answer: Circulating warm chemical solution
84
What prevents rotation and fretting between a thin shell bearing and its housing?
[A]
Location tangs or pegs
[B]
The nip or crush of the bearing
[C]
A special kind of adhesive
[D]
Any of the above
Answer: The nip or crush of the bearing
85
Microbial degradation of main engine sump oils can lead to:
[A]
Increased clogging of lube oil filters
[B]
Corrosive attack on journals and bearings
[C]
Formation of stable emulsions
[D]
All of the above
86
In case of constant pressure turbo charging, the exhaust of the cylinders goes into:
[A]
Small diameter exhaust pipes with exhaust grouping
[B]
Exhaust compensators
[C]
Nozzles
[D]
Large diameter pipes
Answer: Exhaust compensators
87
Which of the following is a limiting factor in cylinder liner cooling?
[A]
Maximum combustion temperature
[B]
Minimum liner temperature
[C]
Exhaust temperature
[D]
Dew point for formation of sulfuric acid
Answer: Dew point for formation of sulfuric acid
88
Which of the following is not a consequence of over lubrication of a cylinder liner?
[A]
Deposits in piston top land which can not only consume lube oil but always lead to increased abrasive wear
[B]
Sticking and jamming of piston rings due to increased deposits.
[C]
Unburnt lube oil in scavenge spaces posing increased risk of scavenge fire
[D]
Increased corrosive wear
Answer: Deposits in piston top land which can not only consume lube oil but always lead to increased abrasive wear
89
Variable geometry turbocharging is the preferred choice over conventional turbochargers because:
[A]
T/C efficiency is very high at high engine loads
[B]
T/C has good starting characteristics while efficiency at full loads is slightly compromised
[C]
T/C efficiency is optimized for different engine loads by changing nozzle ring geometry
[D]
T/C is much cheaper and simple to manufacture and is virtually maintenance free
Answer: T/C efficiency is optimized for different engine loads by changing nozzle ring geometry
90
What type of lubricating oils is generally used in auxiliary engines?
[A]
Detergent
[B]
Alkaline
[C]
Synthetic
[D]
It is not important
91
In the _____ type of t/c 2/s diesel engine is _____ to start.
[A]
constant, easier
[B]
constant, difficult
[C]
pulse, difficult
[D]
none of the above
Answer: constant, difficult
92
Modern marine turbochargers use a ___________ type of compressor
[A]
Radial flow
[B]
Axial flow
[C]
Mixed flow
[D]
Turbulent flow
93
For a main engine fuel system which has a 5 micron filter ,a super decanter is usually fitted ___
[A]
before the purifier
[B]
after the purifier
[C]
after the 5 micron filter to ME
[D]
before the horizontal clarifier
Answer: before the purifier
94
The timing of the engine is delayed. The exhaust temperatures are high. How would you expect this to affect the turbocharger?
[A]
Decreased turbocharger revolutions.
[B]
Surging of the turbocharger.
[C]
Increased turbocharger revolutions
[D]
Higher air and gas temperature after turbocharger.
Answer: Surging of the turbocharger.
95
What is the meaning of the term "valve clearance"?
[A]
The clearance between the rocker arm and valve pushrod.
[B]
The clearance between valve spindle disc and seat.
[C]
The clearance between the rocker arm and camshaft pushrod.
[D]
The clearance between the rocker arm and valve pushrod in either warm or cold state.
Answer: The clearance between the rocker arm and valve pushrod.
96
Which of the following types of crankshafts is much lighter at similar power requirements?
[A]
Fully built type
[B]
Semi built, all welded type
[C]
Semi built type
[D]
Solid forged type
Answer: Semi built, all welded type
97
A unit type fuel injector is used on a diesel engine to
[A]
meter the fuel
[B]
produce the proper fuel oil pressure
[C]
atomize the fuel
[D]
all of the above
98
Too high Calculated Carbon Aromaticity index (CCAI) of fuel oil indicates:
[A]
Reduced ignition delay
[B]
Increased ignition delay
[C]
Reduced chances of knocking
[D]
None
Answer: Increased ignition delay
99
Generator over speed trip what will u check
[A]
governor is not responding (ANS)
[B]
fuel system
[C]
moving parts (crank shaft)
[D]
all of the above
Answer: governor is not responding (ANS)
100
With full load on the main engine, the turbocharger tachometer reads: Too low RPM. Why?
[A]
Damaged connection between pick- up and tachometer unit
[B]
Pick up is not connected to turbocharger.
[C]
Turbocharger need to be cleaned/ overhauled.
[D]
Pick up for tachometer is wrongly adjusted.
Answer: Pick up for tachometer is wrongly adjusted.
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