This Blog is dedicated to all Marine Engineers preparing for MEO class IV exams. The questions covers all functions (Ship Stability, Marine Electro Technology, Marine Engineering Knowledge, Marine Safety and Marine engineering Practice).
2. 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: Cermet coated piston rings, bore cooled liners and uniflow scavenging High top land of piston crown and deeper cylinder cover with top land of crown extending into cylinder cover at TDC Low top land of the piston crown with bore cooled cylinder liner Bore cooled cylinder liner and bore cooled piston crown with toroidal shape combustion chamber
3. Which of the following statements correctly describes the phenomenon of surging in a 2-stroke crosshead type engine? Due to sudden increase in engine load the exhaust gases may flow back through scavenge ports causing surge 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 Due to sudden increase in engine load , the T/C turbine rpm may increase suddenly increasing the compressor pressure ratio to surge 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
4. What is meant by elastohydrodynamic lubrication? Formation of hydrodynamic film under high pressure with minor elastic deformation of mating surfaces, distributing load over a greater area Addition of extreme pressure additive (EP) to the lubricant Addition of Viscosity index improvement additive Addition of elastomer based additives
5. Which of the following will be required to be done in order to reduce sulphur corrosion of Main Engine components Increasing the atomization pressure of fuel injectors Fitting exhaust valves with valve rotators Running engine at or near normal sea load Decreasing the F.O. purifier feed rate , running two purifier in series one acting as purifier and other as clarifier
Score = Correct answers:
2. 58. Any steering gear system alarm can only be successfully acknowledged from __________ choose one The bridge The engine control room The steering compartment The ship's office
3. To check the setting of the overspeed trip on a diesel powered generator, you would use a choose one tachometer torsion meter dynamometer pony brake
4. Which of the following specifications/qualities of cylinder oils counter corrosive wear? choose one Viscosity TBN Detergency Specific Gravity
5. In a bypass type filtering system for a medium or high speed diesel engine, the lube oil bypassing the filter choose one returns directly to the suction side of the pump returns directly to the sump flows to the engine bearings flows through a second-stage strainer, reheater, and returns to the sump
2. For a continuous operation diesel engine, a duplex filter unit would be the best arrangement because choose one changing filter elements would not interrupt engine operation filtering occurs twice in each pass of oil through the system clogging will not occur dropping pressure is half of that through a single filter unit
3. As per regulations, within how many hours before each departure, satisfactory working of thesteering gear must be checked? choose one 2 12 24 none of the above
4. Modern 4-stroke medium speed, marine diesel engine exhaust valve spindles are rotated by providing choose one Nozzle rings Tappet clearance Spinners or vanes Rotocaps
5. If the boiler tubes are scaled on the water side then :- choose one Heat conduction through the tubes will be very high leading to rapid evaporation The boiler furnace can get damaged due to excessive temperatures The surface of the tube will be overheated as heat transfer is impaired The natural circulation of water within the boiler will be more efficient
2. Piston rod stuffing box scraper rings butt clearances should: choose one Not be allowed to fall below 50% of original clearance Not be allowed to increase above 50% of original clearance Not be allowed to fall below manufacturer recommended value Not be allowed to increase above manufacturer recommended value
3. In a 2-stroke engine a ________________ separates the underpiston space from the crankcase. choose one A-frame Crosshead Diaphragm Scavenge space
4. Fusible plugs are installed in fire-tube boilers to choose one provide a means of draining the boiler warn the engineer of low water level cool the crown sheet at high firing rates open the burners' electrical firing circuits
5. Which of the following gauges are generally used to evaluate main bearing clearances? choose one Poker gauge Feeler gauge Telescopic feeler gauge Dial gauge
2. C off a cold boiler equipped with a return flow fuel oil system, the recirculating valve directs the flow of oil choose one directly to the fuel oil heater inlet for further warm-up back to the fuel oil settler for further filtration back to the suction side of the service pump directly to the deep tanks
3. If the tappet clearance between the rocker arm tappet and exhaust valve stem is excessive then: choose one The valve will open early and close later The valve will open later and close early The valve will open and close later The valve will open and close early
4. Which of the following conditions can lead to reduced power developed by a main engine? choose one High scavenge air temperature Choked air suction filter of a turbocharger Blow past in one or more units All of the above.
5. Which of the following types of diagrams would give an indication of effectiveness of exhaust and scavenge processes? choose one Power card Draw card Light spring diagram All of the above.
2. Which of the following is a proper practice to follow in the event of discovery of a small soot fire in exhaust gas boilers? choose one Repeated soot blowing Stopping cooling water circulation Reducing main engine speed Opening the inspection doors and extinguishing the fire
3. The boiler water alkalinity in a coil-type auxiliary boiler should be maintained at the pH recommended by the boiler manufacturer to choose one precipitate silica from solution reduce corrosion in the heating coil prevent clogging and erosion in the coil maintain zero water hardness
4. What does the NLGI number of a grease indicate? choose one The oxidation resistance of the grease The consistency of the grease i.e how fluid or non fluid Demulsibility of the grease The shelf life of the grease
5. Which of the bearings listed is most widely used for main and connecting rod bearings of modern diesel engines? choose one Steel-lined Poured babbitt, self-aligning Split roller Precision insert
2. Which of the following statements is true? The TBN value of cylinder oil should be ideally matched with the sulfur content of the fuel. The TBN value of cylinder oil is not a function of the sulfur content of fuel oil. Cylinder oils with higher TBN values should be used for fuel oils with lower sulfur content The TBN value of cylinder oil is a function of maximum combustion pressure.
3. As per regulations, the velocity capacity of a steering gear system should be such so as to be able to turn the rudder__________________________ 35 degrees one side to 35 degrees on the other side, in 28 seconds at maximum service speed 35 degrees one side to 30 degrees on the other side in 28 seconds at maximum service speed 35 degrees one side to 35 degrees on the other side, in 28 seconds at normal service speed 35 degrees one side to 30 degrees on the other side, in 28 seconds at normal service speed
4. The purpose of valve spindle rotators in case of exhaust valves of modern two stroke engines is to: Improve engine efficiency by allowing even temperature distribution through the combustion chamber Allow even temperature distribution along the disc of the valve spindle, even wear rate and removal of any deposits Utilising waste energy in the exhaust gases to increase the engine efficiency Allow exhaust gases to exit in a rotational motion, inducing good draught of scavenge air for better mixing of air and fuel for effective combustion
2. Which of the following types of scavenging systems is most popular in modern engines? choose one Loop scavenging Cross flow scavenging Uniflow scavenging Reverse scavenging
3. Which of the following can be a consequence of worn scraper rings and sealing rings of a piston rod stuffing box? choose one Increased risk of scavenge fire Increased risk of crankcase explosion Increased Lube oil consumption All of the above
4. The superlong stroke slow speed 2-stroke diesel engines when compared to short stroke version gives choose one Poorer propulsive efficiency but better fuel combustion Better propulsive efficiency but poorer fuel combustion Better propulsive efficiency as well as better fuel combustion Poorer propulsive efficiency as well as poorer fuel combustion
5. Coked material remaining after an oil has been exposed to high temperature, is an indication of the coke forming tendency of the oil. It can be expressed as choose one Conradson Ramsbottom Micro Carbon Residue Any of the above
2. A normal manometer reading of turbocharger air suction filter and normal speed of the turbocharger but reduced scavenge air pressure may be due to: choose one Fouling of the nozzle ring Fouling of diffuser or compressor wheel Fouling of the turbine Cold climate
3. Abnormal wear occurring in engines due to localized welding and fracture is known as ___________________ choose one Scoring Scuffing Peeling None of the above
4. The bearings used to support the crankshaft are generally called choose one line shaft bearings connecting rod bearings main bearings support bearings
5. The flame safeguard control system of a large automatic auxiliary boiler will provide fuel shut off in the case of high choose one water voltage fuel pressure steam pressure
2. A very sudden rise in pressure during combustion accompanied by a metallic, hammer like sound is called knocking of the unit or detonation and usually occurs choose one Near the end of the pressure rise after ignition of fuel charge. Just before the fuel charge is about to ignite. Immediately after the unit reaches peak pressure and before ignition of fuel charge. At any stage of the combustion process
3. Automatic combustion control systems for some auxiliary boilers are designed to cycle burners on in response to choose one low fuel pressure fuel return pressure low steam pressure furnace air pressure
4. One of the major disadvantages of constant pressure turbocharging over pulse pressure turbocharging is : choose one Reduction in specific fuel consumption Lengthening of effective stroke leading to greater expansion in engine Poor turbocharging efficiency Inability of the system to operate at low loads and slow response during acceleration
5. Following method is sometimes used in constant pressure turbochargers of a 4-stroke diesel alternators during starting and rapid acceleration : choose one Auxiliary electrical blowers assisting turbochargers during starting Auxiliary shaft driven blowers assisting turbochargers during starting Auxiliary air drive for turbocharger acceleration during starting Variable geometry turbocharging
