MEK (Motor) asked Questions Part 2




51. The function of the tie rods is to:
A. Keep the engine components under tension at all the times
B. Just secure the engine parts together
C. Act as holding down bolts for the bedplate and keeps all the engine components together
D. Keep engine components under high compression, so that tensile stresses acting during firing stroke do not exceed this pre-compression to avoid fatigue failure

52. 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
53. After an engine has been started using a Bendix drive unit, the drive gear, or pinion disengages from the flywheel due to
A. the action of a spring
B. rotation of the starting cam
C. the higher rotating speed of the flywheel
D. accumulator pressure
54. Fuels as produced in a refinery are generally sterile, however, contamination can occur as fuels are
A. stored at the refinery
B. stored on the vessel
C. transported to the distribution sites
D. All of the above are correct.
55. Which of the following statements is false?
A. Excessive cylinder liner lubrication can aggravate scuffing.
B. Use of anti polishing ring reduces scuffing.
C. Deep honing of liner fails to give an ideal liner surface.
D. None of the above
56. In a fully built or semi built type crankshaft, how can any slippage at shrink fit be identified?
A. By inspecting the locking arrangement provided
B. By checking the dowel provided.
C. By checking the witness mark provided for reference .
D. By checking the performance of the engine
57. Which of the following is one of the major advantages of resin choking over cast iron choking, in holding down arrangements of modern diesel engines?
A. Better vibration damping properties.
B. Better compressive strength
C. 100% contact, no need for surface preparation
D. None of the above
58. In a 2-stroke crosshead type of engine, the side thrust generated due to rolling and connecting rod and fore-aft thrust due to pitching motion of the ship is taken care of by the:
A. Piston and the liner
B. Connecting rod and the piston rod
C. Crosshead shoes and guides
D. Crankpin and thrust bearing
59. In a VIT equipped jerk type fuel pump:
A. Raising the barrel delays beginning of injection
B. Lowering the barrel delays beginning of injection
C. Raising the barrel delays end of injection
D. Lowering the barrel delays end of injection
60. The over speeding of the diesel engine driving an electric generator could cause
A. low voltage trip to trip
B. reverse power trip to trip
C. damage to windings
D. excessive exhaust temperatures
61. In a large, slow-speed, main propulsion diesel engine, which of the parts listed is under tension when the engine is running?
A. Bed plate
B. Column
C. Entablature
D. Tie rod
62. A diffuser is provided at the end of a mechanical atomizer in boiler onboard
A. To prevent blow back of the flame
B. To mix the air and fuel properly
C. To prevent blow out of the flame
D. To eject the excess fumes from the atomizer
63. Steam stop valve is eased of its seat during boiler start up from cold
A. To allow thermal expansion of parts
B. To allow steam flow during start up
C. To prevent water hammer
D. All of the above
64. Which of the following statements about the design of D- type boilers, is false ?
A. The heavier water in top drum flows back to the bottom drum through the down- comers outside the furnace
B. Inside the furnace the water is heated up in the risers
C. The upper drum is the steam/water drum and the lower one is the water drum.
D. The feed water is pumped into the lower drum
65. Presence of catalytic fines in fuel oil is significant to engineers on board because
A. Catalytic fines tend to impair proper operation of purifiers
B. Catalytic fines lead to abrasive wear in liners, piston rings and fuel injection equipment
C. Catalytic fines necessitate increase in injection temperature
D. Catalytic fines necessitate increase in storage temperature
66. With reference to the data logger for a refrigerate sys. Which of the parameters should be noted?
A. Sea water temp, pressure
B. Condenser temp
C. Refrigerant leakage
D. Evaporator temp.
67. Which of the following factors affect penetration of fuel droplets during injection?
A. Quality of atomization
B. Injection temperature
C. Scavenge air pressure
D. All of the above.

68. ESD stands for which type of boiler
A. External superheater D-type
B. Emergency shutdown Boiler
C. Extreme Superheat type
D. External Superheat De-superheater type
69. The advantage of tie rods over an engine without tie rods is that:
A. The engine is very easily aligned after any misalignment has taken place between different components of the engine
B. The engine doesn???t require thrust pads for transmission of thrust to the ship???s hull as the same is being taken care of by the tie rods
C. The engine components are much lighter leading in overall reduction is engine weight with a high power generation with the elimination of fatigue stresses
D. There are no advantages of engines with tie rods, because tie rods require regular maintenance and replacement like connecting rods and overall engine becomes more expensive to operate
70. 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
71. In order for microbiological growths to thrive in a fuel tank it is necessary for
A. high temperatures to exist
B. low temperatures to exist
C. small amounts of water to be present
D. large amounts of water to be present
72. Marine boilers burning H.F.O. face a problem of cold corrosion due to high sulphur content. The minimum flue gas temperature within any boiler part is kept above due point of H2SO4. The actual dew point of H2SO4 in flue gases depends on the:
A. Boiler furnace temperature
B. Ambient air temperature
C. Boiler operating pressure
D. HFO sulphur content and moisture in combustion air
73. The purpose of an air cooler in a supercharging system is to:
A. Reduce temperature of supercharged air in order to condense and remove maximum possible moisture from the air prior entry to the engine
B. Reduce the temperature of the supercharged air in order to increase the density & also to cool down below dew point to remove moisture from air prior entry to the engine
C. Cool supercharged air to increase its density such that the dew point is not reached to avoid entry of moisture into the engine
D. Cool supercharged air to increase it???s density and also to keep the peak temperature and exhaust gas temperature within limits
74. Use of Halon as fire extinguishing medium has been discontinued because
A. It is highly toxic
B. It is expensive
C. It has high Ozone depleting potential
D. It leads to acid rains
75. 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 insertswhich 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
76. 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.
77. Which of the following statements is true?
A. The rotary vane type steering gear generally operates at higher oil pressures than the ram type.
B. The ram type steering gear generally operates at higher oil pressures than the rotary vane type.
C. Both ram type and rotary vane type steering gears generally operate at similar oil pressures
D. None of the above
78. Modern marine turbochargers use a ___________ type of compressor
A. Radial flow
B. Axial flow
C. Mixed flow
D. Turbulent flow
79. 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
80 How is the concentration of dissolved oxygen in the feed water of an auxiliary boiler maintained at acceptable limits?
A. Feed water is cycled through a DC heater.
B. Feed water is treated with phosphates.
C. Oxygen is liberated in the three-stages of feed water preheating.
D. Oxygen is liberated by maintaining the highest practical feed water temperature
81. 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
82. The lube oil pump used in a diesel engine is a
A. volute pump
B. centrifugal pump
C. diaphragm pump
D. gear pump
83. Prior to lighting off a cold automatically fired auxiliary boiler, you should
A. check and regulate the water level
B. close the air cock once fires are lit
C. blow down the gage glass
D. crack the steam stop to assure protective steam flow
84. Steam temperature control for the ESD-II boiler is achieved by :
A. Fitting a de-superheater between 1st & 2nd passes of superheater
B. Fitting an attemperator between 1st & 2nd passes of superheater
C. Gas dampers in boiler uptake
D. Bypassing the superheater
 
85. 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
86. If the combustion control system of an automatically fired auxiliary boiler fails to sustain burner ignition after a normal shutdown, you should check for a/an
A. faulty photocell detector
B. low steam pressure
C. high voltage on the ignition electrode
D. open air damper
87. 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.
88. For a two stroke engine two o-rings are provided on the liner. The function of the top o-ring 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
89. 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
90. Which of the following conditions is responsible for the fuel oil to atomize when using a steam atomizer in an auxiliary boiler?
A. Expansion of the steam in the furnace.
B. Expansion of the steam in the whirling chamber.
C. Expansion of the steam in the orifice plate.
D. All of the above.
91. 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
92. Shaft tunnel requires
a) drain b) escape trunk c) water tight door d) all the above
d
93. What do you mean by surge limit of a turbocharger?
A. Characteristic curve of a turbocharger
B. Portion of compressor characteristic curve which lies on the left side of the point of maximum pressure
C. A line joining all the points of maximum pressure on compressor characteristic curves , drawn at various speeds of operation
D. Maximum rpm limit of T/C above which surging will start
94. 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
95. 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
96. Function of a de-superheater is to.
A. Protect superheater from overheat
B. Control superheater steam outlet temperature
C. Increase the efficiency of the boiler
D. Reduce steam temperature for auxiliary uses after steam superheater
97. Which of the following statements is false?
A. Oxidation of lubricant leads to decrease in its viscosity
B. Formation of oxidation acids, sulfuric acid leads to depletion of TBN of lubricant
C. Contamination with water will lead to decrease in the load carrying capacity of a lubricant .
D. Build up of insolubles will lead to increase in viscosity of a lubricant
98. 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
99. 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
100. 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



3 comments:

  1. question number 63 in this is same as question number 11 in MEK (general) link is http://marinesite.blogspot.in/2013/08/mek-general-objective-questions.html but answers are different... which answer is correct???

    ReplyDelete
  2. Replies
    1. ya itz c.... corrected it.. thkz for ur comnt....

      Delete


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