RUT / REO EXIT EXAM QUESTIONS AND ANSWERS AS ASKED IN DG SHIPPING EXIT EXAM
- 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
- 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
- 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 does not 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
- 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 its density and also to keep the peak temperature and exhaust gas temperature within limits
- 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
- 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 for self-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
- 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.
- Modern marine turbochargers use a _ type of compressor
A. Radial flow
B. Axial flow
C. Mixed flow
D. Turbulent flow
- 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
- In a 2-stroke marine diesel engine if the o-ring for Jacket cooling water sealingis 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
- The lube oil pump used in a diesel engine is a
A. volute pump
B. centrifugal pump
C. diaphragm pump
D. gear pump
- The coating which is provided on the valve stem of exhaust valves of modern marine diesel engines is of:
- 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.
- 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
- 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
- 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
- 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
- A large, low-speed, main propulsion diesel engine uses sea water to directly cool the
A. cylinder heads
B. exhaust valves
C. scavenging air
- 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
- After prolonged operation, jerk type fuel pumps wear on the top edge of plungerand 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
- 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
- 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
- In case of 2-stroke marine diesel engines, the top part of the liner forming the combustion chamber experiences very high pressure induced mechanical stresses as well as high thermal stresses. Which of the following is a correctly designed liner for catering both the above stresses?
A. Thick top portion with jacket cooling to take care of both the high mechanical and thermal stresses
B. Thick top portion to take care of high mechanical stresses while bore cooling to reduce thermal gradients
C. Thin top portion to reduce thermal gradients and hence thermal stresses while supporting ribs to take care of mechanical stresses
D. Thick top portion to take care of high mechanical stresses with jacket cooling combined with allowance for thermal expansion to minimize the thermal stresses
- Which of these fuel oil impurities can cause maximum abrasive damage?
C. Catalytic fines
- In modern marine 2-stroke diesel engines, is sometimes used as a coating on the underside of the exhaust valve disc, to reduce the rate of hot corrosion.
- Irregular circumferential wear of liner due to diminishing neutralizing capacity of cylinder oil away from lubricating holes is known as:
A. Micro seizure
D. Clover leafing
- Which of the following is a reasonable statement about water washing of turbine side of a T/C?
A. It leads to thermal shock and reduces the life of the T/C
B. It leads to thermal shock and not so effective as solid washing
C. If properly carried out keeping rpm, load, temperature limits & other factors into account; it is quite safe and more effective than solid washing
D. It should never be carried out as most of the engine manufacturers recommend against the same
- Which of the following statements correctly describes the phenomenon of surging in a 2- stroke crosshead type engine?
A. Due to sudden increase in engine load the exhaust gases may flow back through scavenge ports causing surge
B. Due to sudden decrease in engine load the turbocharger pressure ratio drops. This causes high pressure downstream of T/C in scavenge trunk causing flow reversal of scavenge air
C. Due to sudden increase in engine load, the T/C turbine rpm may increase suddenly increasing the compressor pressure ratio to surge
D. Due to sudden decrease in engine load, the turbocharger may stall as the higher pressure downstream in exhaust system may cause reversal of flow of exhaust gases
- To check the setting of the over speed trip on a diesel powered generator, you would use a
B. torsion meter
D. pony brake
- Which of the following specifications/qualities of cylinder oils counter corrosive wear?
D. Specific gravity
- What is meant by elastohydrodynamic lubrication?
A. Formation of hydrodynamic film under high pressure with minor elastic deformation of mating surfaces, distributing load over a greater area
B. Addition of extreme pressure additive (EP) to the lubricant
C. Addition of Viscosity index improvement additive
D. Addition of elastomer based additives
- In a bypass type filtering system for a medium or high speed diesel engine, the lube oil bypassing the filter
A. returns directly to the suction side of the pump
B. returns directly to the sump
C. flows to the engine bearings
D. flows through a second-stage strainer, reheated, and returns to the sump
- Types of corrosion in fresh water of Diesel Engines
B. Hot corrosion
D. Selective phase corrosion
- Which of the following types of damages are metal seating’s of a valve subject to? Choose the correct alternative.
A. Corrosion, Erosion, Abrasion, Deformation
B. Corrosion, Fatigue failure, brittle fracture, caustic cracking
C. Erosion, caustic cracking, brittle fracture, Clover leafing
D. None of the above
- When A/E stand by F.O. heater to be used for main engine
A. Sudden opening F.O. inlet valve pressurized and damage the heater
B. F.O. in vapor lock inside heater allow steam
C. F.O. inlet valve causes pressure drop M/E F.O. pressure standby water is not pressurized may cause sudden change in engine /per load/rpm
D. Heater leaking.