- Viscosity of fuel oil used for ME was 145cst, new fuel comes whose viscosity wasmore than earlier, what u should do
A. Increase temp setting
B. Change setting of viscotherm
C. Do nothing
D. Open steam valve manually more
- Which of the following can be done to reduce the cold corrosion of Main Enginecylinder liners using high sulphur fuel oil
A. Increasing cylinder oil feed rate
B. Using high TBN cylinder oil
C. Increasing scavenge air temperature
D. Decreasing cylinder oil feed rate
- When main engine is running in emergency condition which of the alarms can’t be bypassed
A. LO low pressure
B. Jacket water high temp
C. Piston cooling water high temp
D. All the above
- Which of the following will be required to be done in order to reduce sulphur corrosion of main Engine Components?
A. Increasing the atomization pressure of fuel injectors
B. Fitting exhaust valves with valve rotators
C. Running engine at or near normal sea load
D. Decreasing the F.O. purifier feed rate, running two purifiers in series one acting as purifier and other as clarifier
Answer-A, B, C and D
- Sudden stop of diesel engine (multiple choices)
A. air in system
B. water in system
C. air filter chocked
D. water in air filter Answer-A, B and C
- Mixed lubrication consist of
A. Mix two lubes oil
B. Contamination of hydrodynamic lube oil.
C. Mixed grease and oil
- The muffling of exhaust gas noise in 4 stroke auxiliary engines in achieved by
A. Allowing the gas to expand.
B. Change the direction of their flow.
C. Cool the gas with injected water.
D. Cool the gas with scavenges air.
- An auxiliary engine turbocharger makes strange noises when the load changes. The engine parameters however are absolutely fine. An external examination of turbocharger parameters as stated in the manual also reveals nothing. Would you
A. Continue to run the engine and wait for some time
B. Stop the engine for a while and make some checks
C. Reduce the load of the engine
D. Run it on steady load to make some checks.
- To avoid the engine running too long on critical speed during start up it is necessary to
A. Start at speeds above critical speed.
B. Start at speeds just below critical speed and quickly move across the critical speed.
C. Start at maximum speed and quickly bring down to just above critical speed.
D. Eliminate totally the hazards of critical speed by ignoring it.
- Supercharging an existing medium speed naturally aspirated engine will
A. Reduce weight of the engine.
B. Reduce bulk of the engine.
C. Increase existing power.
D. Increase piston speed.
E. Reduce fuel consumption. Answer-C and E
- When using low sulfur fuel oil for Emission Control Areas (ECA’S), ideally the TBN of the cylinder oil used should be
A. Lower than normal
B. Higher than normal
C. Same as normal
D. Same as normal if the feed is kept higher
- Which of the following functions is done by a cam operating an exhaust valve?
A. It governs the timing of opening and closing of the valve.
B. It governs the speed at which the valve operates
C. It governs the amount of opening of the valve
D. All of the above
- In the latest concept of Variable Geometry Turbocharging, _………. angle can be varied to match the turbocharger at varying engine loads
A. Compressor vane
B. Turbine blade
C. Nozzle ring blade
D. Diffuser ring blade
- Directional intake ports in diesel engines are used to
A. reduce air charge turbulence
B. induce air swirl
C. deflect hot combustion gas away from the valves
D. oppose the effects of piston induced squish
- Why does a chain stretch in service?
A. Due to plastic elongation
B. Due to high temperature expansion
C. Due to wear on rollers and bushes
D. Due to the phenomenon of creep
- 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
- What is the purpose of the inlet grid provided within the exhaust gas casing in the gas flow path, prior entry to turbocharger?
A. To filter out any unburned carbon
B. To absorb and dampen the pressure fluctuation
C. To reduce noise in the constant pressure exhaust piping
D. To prevent any broken piston rings finding their way to turbine
- The main function of tie rods in the construction of large, low speed diesel engines is to
a. stiffen the bedplate in way of the main bearings to increase the engine’s longitudinal strength
b. accept most of the tensile loading that results from the firing forces developed during operation
c. mount the engine frame securely to the hull to prevent shaft coupling misalignment
d. connect the crosshead solidly to the piston rod
- The fall in speed that occurs in a diesel engine equipped with governor, on increase of load is called:
b. Speed drop
c. Speed droop
d. Speed offset
- Which of the following factors governs the lower limit of thrust bearing clearance?
A. To allow some oil leakage to prevent overheating
B. Reduction of oil viscosity
C. Alignment of crankshaft
D. To allow the thrust pads to tilt and generate the oil wedge
- Which of the following can result in cracking of piston crown?
A. Deposits in cooling spaces
B. Impingement of fuel due to faulty injection
C. Insufficient piston cooling oil flow
D. All of the above
- What does the NLGI number of grease indicate?
A. The oxidation resistance of the grease
B. The consistency of the grease i.e how fluid or non fluid
C. Demulsibility of the grease
D. The shelf life of the grease
- Which of the following layers of a thin shell bearing gives it its fatigue strength?
A. The overlay
B. The interlay
C. The backing
D. The barrier layer
- Which of the bearings listed is most widely used for main and connecting rod bearingsof modern diesel engines?
B. Poured babbitt, self-aligning
C. Split roller
D. Precision insert
- Which of the following statements is false?
A. The fuel oil sulfur level is one of the important criteria for choice of TBN level of cylinder oil.
B. The use of anti-polishing rings or flame rings increases the consumption of cylinder oil
C. Excessive cylinder oil feed can lead to harmful deposits in piston top land area
D. None of the above
- Prompt correction of speed of diesel engines driving alternators, without havingmassive fluctuations is ensured by incorporating:
A. Load limiting devices
B. Load sharing devices
C. Load sensing devices
D. Load shedding devices
- In a uniflow scavenged marine 2-stroke diesel engine, the scavenge ports in a cylinder liner are
A. Only for a part of the circumference, at an angle almost tangential to the circumference of the liner
B. All around the circumference at right angles to the circumference of the liner
C. only for a part of the circumference, at right angles to the circumference of the liner
D. All around the circumference at an angle almost tangential to the circumference of the liner
- If the tappet clearance between the rocker arm tappet and exhaust valve stem is excessive then:
A. The valve will open early and close later
B. The valve will open later and close early
C. The valve will open and close later
D. The valve will open and close early
- In order to reduce thermal loading on the upper part of the liner and increase the effectiveness of cylinder lubrication, modern 2-stroke marine diesel engines are designed to have:
A. Cermets coated piston rings, bore cooled liners and uniflow scavenging
B. High top land of piston crown and deeper cylinder cover with top land of crown extending into
C. cylinder cover at TDC
D. Low top land of the piston crown with bore cooled cylinder liner
E. Bore cooled cylinder liner and bore cooled piston crown with toroidal shape combustionchamber
- Which of the following conditions can lead to reduced power developed by a main engine?
A. High scavenge air temperature
B. Choked air suction filter of a turbocharger
C. Blow past in one or more units
D. All of the above.
- Which of the following types of diagrams would give an indication of effectivenessof exhaust and scavenge processes?
A. Power card
B. Draw card
C. Light spring diagram
D. All of the above.
- As a thumb rule, ovality in crankpins of medium speed engines should not exceed……..
of bearing clearance.
- In a naturally aspirated diesel engine, the volume of air intake is directly relatedto engine
A. compression ratio
B. valve size
C. fuel pressure
D. cylinder clearance volume
- Piston rod stuffing box scraper rings butt clearances should:
A. Not to be allowed to fall below 50% of original clearance
B. Not to be allowed to increase above 50% of original clearance
C. Not to be allowed to fall below manufacturer recommended value
D. Not to be allowed to increase above manufacturer recommended value
- In a 2-stroke engine a …….. separates the under piston space from the crankcase.
D. Scavenge space