Sunday, 12 July 2020

INTERNAL COMBUSTION ENGINE meo class IV objective questions with answer.(Part-3)

  • When using a high BN MECYL oil and suddenly the ship has to use low sulphur 380 cst HO in the ME, due to SECA area entry--

a)reduce the feed of MECYL

b)increase the feed of MECYL

c)do not change the feed rate

d)increase the BN of the MECYL

Answer-A


  • ME scavenge air temperature is adjusted by

a)controlling the sea water inlet

b)controlling the sea water outlet

c)keeping outlet valve 100% open always.

d)none of above

Answer-B


  • The ME jacket FW cooling outlet temperature is-

a)80C

b)95C

c)50C

d)55C

Answer-A


  • The scavenge air high temperature set point for 2 stroke ME is

a)40C

b)55C

c)65C

d)35C

Answer-B


  • You see white smoke coming from the ME funnel stack, this could be

a)one or more cylinders not getting enough fuel

b)too low compression pressure

c)water in fuel

d)all of above

Answer-C


  • The crank angles of a 2 stroke engine are

a)2 cylinder engine/ 90 degrees

b)4 cylinder engine/ 60 degrees

c)6 cylinder engine/ 90 degrees

d)4 cylinder engine/ 90 degrees

Answer-D


  • Crankcase explosions of main engines can be due to-

a)over heating of MECC oil

b)poor condition of liners/ rings

c)crankshaft / thrust bearing failure

d) all of above

Answer-D


  • If there is air in the fuel oil filter, the compression and reexpansion of air will

a)not allow the fuel injection valve to close

b)not allow the fuel injection valve to open

c)makes no difference

d)none of the above

Answer-B


  • Which of the bearings listed are most widely used for the main and connected rod bearings of a diesel engine?

a)roller

b)sleeve

c)precision insert

d)needle

Answer-C


  • Which of the following methods is normally used to lubricate bearings in a small high-speed diesel engine?

a)splash lubrication

b)pressure lubrication

c)sight feed lubricators

d)mechanical lubricators

Answer-B


  • In a naturally aspirated diesel engine, the volume of air intake is directly related to engine

a)compression ratio

b)valve size

c)fuel pressure

d)cylinder clearance volume

Answer-B


  • In a bypass 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, reheater, and returns to the sump

Answer-C


  • In a diesel engine, the main bearings are used between the

a)connecting rod and the crankshaft

b)wrist pin and the connecting rod

c)camshaft and the engine block

d)crankshaft and the engine block

Answer-D



  • Heat exchangers are most commonly found in a small auxiliary diesel engine

a)fuel oil system

b)governing system

c)air starting system

d)lube oil system

Answer-D


  • Multiple concentric valve springs are often used with diesel engine valves to

a)enable research and development of cam contour to be simplified

b)operate the valve gear where the larger force is required, but space limitations restrict use of a large spring

c)allow for easier valve replacement

d)enable a total smaller valve spring force to keep the valve tight on its seat

Answer-B


  • Which of the listed bearing installations is subjected to swinging motion?

a)crankshaft journal

b)crankpin bearings

c)wrist pin bearings

d)thrust bearings

Answer-C


  • One advantage of vacuum feed type cylinder lubricators over the liquid sight type is

a)there are fewer moving parts

b)adjustment is not required

c)better metering accuracy

d)a lower grade of oil may be used

Answer-C


  • Cooling water pumps driven by direct reversing diesel engines are usually of the straight impeller vane type -pump with a concentric housing to

a)provide cooling water flow when the engine is running either ahead or astern

b)provide the greatest pump efficiency

c)prevent pump clogging from marine growth

d)prevent cavitation at the pump outlet

Answer-A


  • Motor vessels usually have an independent lube oil system each for the main engine and main reduction gears because

a)coolers are not needed for the gear system

b)contaminants produced by the engine could harm the reduction gears

c)non additive oils are used in the main engine system

d)different type centrifuges are required for the main engine and reduction gear lube systems

Answer-B



  • Fuel oil penetration into the cylinder of a diesel engine is

a)dependent on air turbulence

b)reduced by finer atomization

c)increased by finer atomization

d)non-existent in the precombustion chamber system

Answer-B


  • Precombustion chambers, air cells, and energy cells in high-speed, small bore diesel engines all serve to increase

a)firing pressure

b)ignition quality of fuel

c)fuel-air ratio during compression

d)turbulence

Answer-D


  • Which of the following statements best describes the operational characteristics of an isochronous governors?

a)they are suitable for use on main propulsion units

b)they strive to maintain a constant engine speed for all values of steady load

c)they cause a proportional drop in engine speed as the load is increased

d)they have poor sensitivity at high RPM.

Answer-B


  • Theoretical perfect combustion in a diesel engine yields by-products of

a)aldehydes and carbon dioxide

b)water vapour and carbon monoxide

c)nitrogen and carbon monoxide

d)water vapour and carbon dioxide

Answer-D


  • Combustion knock can occur in the cylinders of a diesel engine under any condition permitting

a)a shortened ignition delay period

b)a lean fuel/air mixture

c)excess fuel in the combustion chamber

d)rapid vaporisation of injected fuel droplets

Answer-C


  • When exessive fuel dilution is noted in the lube oil, the oil should be

a)centrifuged

b)filtered

c)strained

d)changed

Answer-D


  • Sticking of diesel engine piston compression rings may be caused by

a)high compression pressure

b)excessive ring action

c)excessive cylinder lubrication

d)improper ring rotation

Answer-C


  • When fuel is injected late into a diesel engine cylinder,

a)the exhaust will be clear

b)fuel consumption will be low

c)all the fuel will be burned at top dead center

d)fuel consumption will be high

Answer-D


  • ME LO inlet temperature should be

a)40C

b)50C

c)60C

d)55C

Answer-A


  • Exhaust temp of one ME cylinder high could mean

a)fuel valves need overhaul

b)exh valve leakage

c)piston ring blow past

d)all of above

Answer-D


  • For a 2 stroke engine with exhaust ports

a)scavenge ports close before exhaust ports

b)exhaust ports close before scavenge ports

c)scavenge ports and exhaust ports close at same time before BDC

d)scavenge ports and exhaust ports close at same time after BDC

Answer-A


  • For a 2 stroke engine with exhaust valves

a)scavenge valve closes before exhaust ports

b)exhaust valves close before scavenge valves

c)scavenge and exhaust valves close at same time before BDC

d)scavenge and exhaust valves close at same time after BDC

Answer-B


  • The maximum amount of liner wear occurs at

a)top of liner

b)1/ 3 downward from top centre

c)midway

d)bottom of liner

Answer-B

64)Which of the following cannot be removed from fuel oil by centrifuging in the purifier and micro-filtration

a)sodium

b)aluminium and silicon

c)vanadium

d)ash

Answer-C


  • In the preheater before purifier the recommended heavy oil preheat is-

a)85c

b)98C

c)110C

d)120c

Answer-B


  • For a ME which has a 5 micron fuel filter, a homogenizer ( omega fire ) 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-B


  • 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-A


  • For low sulphur 380 cst fuels the TBN of MECC oil should be in the region of

a)20

b)40

c)60

d)70

Answer-A


  • Using a MECC oil of high BN can cause

a)improper centrifuging of water

b)Calcium laquer deposits on bearings

c)sludge formation with water in ME sump

d)all of above

Answer-D


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