national maritime center - dco.uscg. · pdf filenational maritime center ... the function of...

National Maritime Center Providing Credentials to Mariners

U.S.C.G. Merchant Marine Exam

Assistant Engineer-Limited

Q610 Motor Plants

(Sample Examination)

of 33 Q610 Motor Plants

8/30/2017

U.S.C.G. Merchant Marine Exam Assistant Engineer-Limited Q610 Motor Plants Illustrations: 17

Choose the best answer to the following Multiple Choice Questions.

1. The function of the synchronizing motor on the generator governor illustrated is to __________. Illustration MO-0092

o (A) drive the terminal shaft at a set speed o (B) turn the governor drive shaft during start-up • (C) provide remote control for speed adjustment o (D) power the generator synchronizing lamps

If choice C is selected set score to 1.

2. The device shown in the illustration is a __________. Illustration MO-0008

o (A) rotary type mist detector, designed for use in four-stroke, high-speed diesel engines o (B) photoelectric, explosive gas indicator, for use in high-speed, two-stroke, trunk type piston

engines • (C) comparator type mist detector for large low-speed, crosshead type engines o (D) level type explosimeter, for small medium-speed, trunk type piston engines


3. In a turbocharger, inlet air velocity is increased in the __________.

o (A) inlet nozzle ring o (B) stationary diffuser passages o (C) compressor outlet volute • (D) rotating impeller vanes

If choice D is selected set score to 1.

4. Which of the tanks, shown in the illustration, supplies fuel to the emergency generator? Illustration MO-0058

• (A) Light fuel oil service tank o (B) Light fuel oil settling tank o (C) Light fuel oil boiler tank o (D) Light fuel oil booster tank

If choice A is selected set score to 1.


8/30/2017

U.S.C.G. Merchant Marine Exam Assistant Engineer-Limited Q610 Motor Plants Illustrations: 17 5. Whether using a centrifuge or a simple filter, oil cleaning and filtration will be the most effective when

the oil is at a __________.

o (A) high temperature and a high viscosity • (B) high temperature and a low viscosity o (C) low temperature and a high viscosity o (D) low temperature and a low viscosity

If choice B is selected set score to 1.

6. The diesel engine connecting rods shown in the illustration are distinctively named __________. Illustration MO-0122

• (A) fork and blade o (B) male and female o (C) hook and nail o (D) left hand and right hand


7. The formation of carbon monoxide in diesel exhaust gases is reduced by __________.

o (A) spraying water into the exhaust pipe o (B) keeping the exhaust system free of carbon deposits • (C) maintaining proper combustion and scavenging o (D) avoiding light load operation


8. A diesel engine with a full speed of 1000 RPM drives a propeller at 300 RPM. What is the speed reduction ratio?

o (A) 0.3 to 1 • (B) 3.33 to 1 o (C) 33 to 1 o (D) 300 to 1


9. The temperature of the contaminated fuel oil fed to the centrifuge shown in the illustration should be __________. Illustration MO-0012

o (A) 160°F to 180°F • (B) 203°F to less than 212°F o (C) greater than 212°F o (D) selected according to the oil's viscosity index



8/30/2017

U.S.C.G. Merchant Marine Exam Assistant Engineer-Limited Q610 Motor Plants Illustrations: 17 10. A four-stroke eight cylinder in-line medium-speed diesel engine has a firing order of 1-5-2-6-8-4-7-3.

If No.4 piston is at TDC and firing, how many degrees of crankshaft rotation will occur when No.5 piston reaches TDC and fires?

o (A) 120 degrees o (B) 180 degrees o (C) 240 degrees • (D) 360 degrees


11. The pressure in an operating diesel engine cylinder continues to rise for a short period after the piston passes top dead center as a result of the __________.

• (A) expansion during the combustion process o (B) exhaust and intake valves just closing o (C) maximum compression pressure is just being attained o (D) fuel injection occurring at that point and combustion begins


12. When an engine fitted with a hydraulic starting system starts up, the starter is protected from the higher speed of the engine by __________.

o (A) the immediate increase in hydraulic pressure • (B) the overrunning clutch o (C) closing the starting check valves o (D) the pivoting of the shaft from being engaged with the flywheel


13. The rate of heat transfer in a water-tube auxiliary boiler can be increased by __________.

o (A) operating the boiler at less than normal water level • (B) installing fins on the firesides of water-tubes o (C) increasing the amount of excess air to the burners o (D) treating the boiler water with chemical oxygen scavengers


14. Clutching takes place nearest the bearing shown in the illustration, located at number _____. Illustration MO-0086

• (A) 1 o (B) 2 o (C) 3 o (D) 4



8/30/2017

U.S.C.G. Merchant Marine Exam Assistant Engineer-Limited Q610 Motor Plants Illustrations: 17 15. Which of the following statements is true concerning the air starting valve, labeled "III", as shown in

the illustration? Illustration MO-0046

o (A) During normal engine running, the air starting valve opens and closes constantly due to cam action.

• (B) The air starting valve is opened by cam action. o (C) When starting air is secured, the air starting valve is closed. o (D) When starting, the air starting valve is held open by air pressure.


16. When is fuel injected into a cylinder of diesel engines?

o (A) Before air in the cylinder is compressed. • (B) After air in the cylinder is compressed. o (C) After combustion gases in the cylinder have expanded. o (D) As air is taken into the cylinder.


17. Most practical diesel engines today operate on a cycle which is a combination of the Diesel and Otto cycles. In this process, compression ignition __________.

• (A) begins on a constant volume basis o (B) begins on a constant pressure basis o (C) ends on a constant volume basis o (D) begins and ends on a constant volume basis


18. To minimize corrosion, fuel oil strainer disks, spacers and scraper blades are made of __________.

o (A) brass o (B) copper o (C) iron • (D) monel metal or stainless steel


19. With respect to diesel fuel, the ease with which a cold engine will start is dependent upon the __________.

• (A) ignition quality of the fuel o (B) high heating value of the fuel o (C) amount of carbon residue after combustion o (D) internal flow resistance in the injectors



8/30/2017

U.S.C.G. Merchant Marine Exam Assistant Engineer-Limited Q610 Motor Plants Illustrations: 17 20. Which of the routine maintenance procedures listed is required for starting air receivers?

• (A) Frequent draining of accumulated moisture. o (B) Frequent testing of relief valves. o (C) A close watch on temperature to prevent fluctuations in pressure. o (D) Frequent cleaning to remove oil and foreign matter.


21. The valve stem expansion associated with engine warm-up is allowed for by the __________.

o (A) valve springs o (B) hydraulic governor • (C) valve lash adjusters o (D) cooling system


22. As shown in the illustration of the fuel injection pump, the component labeled "C" would be identified as the __________. Illustration MO-0061

o (A) control rack o (B) sleeve • (C) plunger o (D) barrel


23. A characteristic of a bearing material which permits small dirt particles to become embedded in the bearing surface is __________.

• (A) desirable, as it will minimize damage to the journal surface o (B) desirable, as it will assist in keeping the lube oil filters clean o (C) undesirable, since the embedded particles will score the journal o (D) undesirable, since the particles will interfere with lube oil flow


24. Which of the air intake systems listed will result in the lowest specific fuel consumption?

o (A) Natural aspiration • (B) Turbocharged o (C) Roots blower o (D) Piston blower



8/30/2017

U.S.C.G. Merchant Marine Exam Assistant Engineer-Limited Q610 Motor Plants Illustrations: 17 25. An immediate repair is required if a leak occurs in the high-pressure fuel piping between the injection

pump and fuel nozzle because of the __________.

o (A) high cost of fuel • (B) serious fire hazard o (C) pollution hazard o (D) poor combustion which will occur in that cylinder


26. A large, low-speed, main propulsion diesel engine uses sea water to directly cool the __________.

o (A) cylinder heads o (B) exhaust valves • (C) scavenging air o (D) injectors


27. Integral cylinder liners constructed as part of the cylinder block, are characterized by which of the following disadvantages?

o (A) They conduct heat poorly. o (B) They must operate with lower mean effective pressures. • (C) They cannot be replaced. o (D) They require special tools for removal.


28. A diesel engine experiences a sudden loss in speed, accompanied by black exhaust smoke, with the fuel rack at maximum, and the speed remaining below normal. The probable cause is __________.

• (A) engine overload o (B) leaky valves o (C) stuck or broken piston rings o (D) low air injection pressure


29. In the illustrated diesel engine, which label points to the piston? Illustration MO-0122

o (A) K o (B) 3 • (C) 4 o (D) 6



8/30/2017

U.S.C.G. Merchant Marine Exam Assistant Engineer-Limited Q610 Motor Plants Illustrations: 17 30. Auxiliary diesel engines can be automatically shut down as a result of __________.

o (A) low lube oil temperature • (B) low lube oil pressure o (C) high exhaust temperature o (D) high cooling water pressure


31. The overspeeding of the diesel engine driving an electric generator could cause __________.

o (A) low voltage trip to trip o (B) reverse power trip to trip • (C) damage to the field windings o (D) excessive exhaust temperatures


32. The small end of the connecting rod is attached to the piston with a __________.

o (A) torque bushing o (B) crank pin • (C) wrist pin o (D) sliding wedge


33. In a modern internal combustion diesel engine, the load carrying part of the engine is referred to as the __________.

• (A) bedplate or base o (B) sump or oil pan o (C) cylinder block o (D) frame


34. The principal characteristic of an isochronous governor is it will __________.

o (A) slow the machine down as the load is increased o (B) shut down the engine if it overspeeds o (C) display excessive speed droop • (D) maintain a constant speed with variations of load



8/30/2017

U.S.C.G. Merchant Marine Exam Assistant Engineer-Limited Q610 Motor Plants Illustrations: 17 35. The purpose of the energy cell, or air cell, is to __________.

o (A) cause auto-ignition in the cell rather than in the main combustion chamber • (B) create a high turbulence within the main combustion chamber o (C) allow the spray to hit the piston rim rather than the cooler cylinder wall o (D) make a blast in the main chamber prior to the piston expansion stroke


36. When a nozzle tester is being used to test a "closed" type fuel injection nozzle, a clogged nozzle orifice will be indicated by a __________.

• (A) distorted spray pattern o (B) chattering sound when the nozzle closes o (C) squealing sound mid-way in the pump stroke o (D) popping sound when the nozzle opens


37. Which of the components listed is only found in an opposed-piston engine?

o (A) Exhaust valves o (B) Scavenging ports o (C) Combustion chambers • (D) Upper and lower crankshafts


38. The section of the turbocharger which would be connected to the after cooler inlet is labeled __________. Illustration MO-0080

• (A) B o (B) C o (C) H o (D) K


39. The item labeled #16 in the illustration is a stack of spring washers. Their function is to __________. Illustration MO-0062

o (A) absorb the high-pressure pulses developed during the fuel injection process o (B) permit accurate stretch gauge measurement of bolt elongation during installation o (C) prevent bolt failure by allowing limited movement of the injector when excessively high

cylinder pressures are developed • (D) maintain the same hold-down force on the injector regardless of varying engine operating

temperatures



8/30/2017

U.S.C.G. Merchant Marine Exam Assistant Engineer-Limited Q610 Motor Plants Illustrations: 17 40. The minimum fuel oil delivery pressure required for efficient injection depends primarily on the

__________.

o (A) degree of cylinder air turbulence • (B) maximum pressure in the engine cylinders during injection o (C) quantity of the fuel to be injected o (D) duration of the injection delay period


41. If the jacket water temperature rises rapidly above normal in a diesel engine, you should FIRST __________.

o (A) clean sea water strainer • (B) reduce engine load o (C) call the chief engineer o (D) check thermostatic valve


42. Proper atomization of fuel in diesel engine combustion chambers will __________.

o (A) affect the injection pressure • (B) improve combustion o (C) reduce compression pressure o (D) decrease power output


43. The fuel injector for the diesel engine shown in the illustration, is identified as _________. Illustration MO-0122

• (A) "19" o (B) "H" o (C) "M" o (D) "Z"


44. Sensitivity for a diesel engine governor is described as the __________.

o (A) governor's speed droop response to variations in engine load o (B) ability to maintain desired engine speed without speed fluctuation • (C) percent of speed change necessary for corrective action by the fuel control o (D) ability to maintain constant speed regardless of engine load



8/30/2017

U.S.C.G. Merchant Marine Exam Assistant Engineer-Limited Q610 Motor Plants Illustrations: 17 45. Which of the following should always be checked prior to starting a diesel engine?

o (A) Air filters o (B) Fuel oil strainers • (C) Crankcase oil level o (D) Pyrometer readings


46. The exhaust system for a turbocharged diesel engine functions to __________.

o (A) power the after coolers • (B) power the turbocharger o (C) reduce the cylinder scavenge effect o (D) cool the turbocharger


47. The process of scavenging a two-stroke cycle diesel engine serves to __________.

o (A) improve fuel flow volume • (B) cool the exhaust valves o (C) reduce the intake air charge density o (D) increase the temperature of exhaust gases


48. White smoke issuing from the exhaust of an auxiliary diesel engine could mean __________.

o (A) the engine is overloaded • (B) the engine is cold o (C) there is too much lube oil in the cylinders o (D) the turbocharger is fouled


49. If the analysis of used lube oil indicates a high content of iron particles, this could indicate __________.

o (A) corrosive deterioration of a bearing o (B) inadequate air filtration • (C) excessive ring and liner wear o (D) excessive cooling of lubricating oil



8/30/2017

U.S.C.G. Merchant Marine Exam Assistant Engineer-Limited Q610 Motor Plants Illustrations: 17 50. Opposed-piston diesel engines are classified as __________.

• (A) two-stroke cycle single acting o (B) two-stroke cycle double acting o (C) four-stroke cycle single acting o (D) four-stroke cycle double acting


51. Open combustion chambers are designed to __________.

o (A) eliminate carbon buildup o (B) improve piston cooling o (C) prevent air charge turbulence • (D) provide proper fuel/air mixing


52. Which of the diesel engine exhaust mufflers listed is usually equipped with a spark arrestor?

o (A) A wet-type exhaust muffler o (B) A constant pressure muffler • (C) A dry-type exhaust muffler o (D) A constant velocity muffler


53. Auxiliary boilers are divided into several classifications, one of which is __________.

o (A) water-tube supercritical circulation • (B) water-tube forced circulation o (C) fire-tube controlled circulation o (D) fire-tube express circulation


54. As shown in the illustration, the component labeled "F" would be identified as a ________. Illustration MO-0128

o (A) main condensate pump o (B) fuel oil service pump • (C) boiler water feed pump o (D) waste heat boiler circulating pump



8/30/2017

U.S.C.G. Merchant Marine Exam Assistant Engineer-Limited Q610 Motor Plants Illustrations: 17 55. The load is always placed on the lower half of the main bearings in a __________.

• (A) two-stroke cycle engine o (B) four-stroke cycle engine o (C) reverse cycle engine o (D) double acting engine


56. What prevents the thrust bearing blocks shown in the illustration from rotating within the housing? Illustration MO-0120

o (A) The bearing blocks are massive and their weight provides sufficient force to prevent rotation. • (B) Found within the thrust bearing cap or cover are extended protrusions to position the thrust

shoe segments and maintain minimum clearance. o (C) The bearing assembly is specifically designed to allow for rotation, permitting the transmittal

of axial forces across a greater surface area and minimizing loading densities. o (D) The thrust shoes are dovetailed into the collar.


57. Before any auxiliary diesel engine hydraulic starting system is opened for servicing or repair, you must __________.

o (A) place all control levers in the "HOLD" position o (B) ensure that the hydraulic fluid reservoir is full o (C) block all hydraulic hoses using high-pressure covers • (D) bleed off all hydraulic pressure from the system


58. Excessive alkalinity of the water in an auxiliary boiler can cause __________.

• (A) caustic embrittlement of the boiler metal o (B) acidic corrosion of the boiler metal o (C) hard scale deposits on the boiler tubes o (D) etching of the heat exchange surfaces


59. When operating the HFO purifiers in "parallel", as shown in the illustration __________. Illustration MO-0077

o (A) valve "2" would be closed o (B) valve "3" would be closed • (C) valve "6" would be closed o (D) All of the above



8/30/2017

U.S.C.G. Merchant Marine Exam Assistant Engineer-Limited Q610 Motor Plants Illustrations: 17 60. Proper housekeeping to prevent the formation of microbiological growths within a fuel system

includes the prevention of water accumulations and the use of __________.

o (A) steam coils o (B) fuel oil centrifuges o (C) fuel oil discharge filters • (D) chemical additives called biocides


61. An auxiliary diesel-generator continues to run after you try to shut down. Your next course of action should be to _________.

• (A) block the flow of air supply to the engine o (B) engage the jacking gear o (C) secure the lube oil pump o (D) decrease control air pressure


62. One of the factors limiting the amount of load which can be put on a modern marine diesel engine is the __________.

o (A) governor sensitivity • (B) exhaust temperature o (C) fuel injection pressure o (D) speed of the camshaft


63. A main propulsion diesel engine is normally shutdown by __________.

o (A) shutting off the air supply o (B) overspeeding the engine • (C) securing the fuel supply o (D) securing the ignition system


64. Which of the operating characteristics listed is correct concerning the blower shown in the illustration? Illustration MO-0082

o (A) Each of the lobes are in constant contact with each other. o (B) Air delivery is inversely proportional to engine speed. • (C) Air delivery is approximately proportional to engine speed. o (D) The blower is driven by engine exhaust gases.



8/30/2017

U.S.C.G. Merchant Marine Exam Assistant Engineer-Limited Q610 Motor Plants Illustrations: 17 65. Which of the indicator diagrams illustrated depicts the condition that should be corrected by retarding

only the timing? Illustration MO-0029

• (A) A o (B) B o (C) C o (D) D


66. The use of push rods becomes necessary in a diesel engine when __________.

• (A) the camshaft is located some distance below the valve gear o (B) the rocker arms are pivoted near their centers o (C) two or more valves must be opened and closed at the same time o (D) hydraulic valve lash adjusters are used


67. The amount of fuel delivered by a unit injector is controlled by the __________.

o (A) camshaft o (B) main spring • (C) rack position o (D) engine speed


68. The lube oil strainer shown in the illustration is used on the reduction gear of a mid-size diesel engine. The strainer elements consist of __________. Illustration MO-0057

o (A) pleated paper o (B) wire mesh o (C) fibrous braid • (D) metal disks


69. The PRIMARY function of a waste heat boiler is to __________.

o (A) reduce engine exhaust noise o (B) reduce engine back pressure • (C) recover heat which otherwise would be lost o (D) increase turbocharger efficiency



8/30/2017

U.S.C.G. Merchant Marine Exam Assistant Engineer-Limited Q610 Motor Plants Illustrations: 17 70. The diesel engine shown in the illustration has the highest fuel pressure developed in the part

labeled __________. Illustration MO-0003

• (A) E o (B) X o (C) Y o (D) Z



8/30/2017


6/3/2016

MO-0003

Adapted for testing purposes only from ROWEN, Introduction to

Practical Marine Engineering, Volume 2

Copyright © 2005 The Society of Naval Architects and Marine Engineers

Further reproduction prohibited without permission. of 33 Q610 Motor Plants


6/3/2016

MO-0008

Adapted for testing purposes only from LILLY, Diesel Engine Reference Book

Copyright © 1984 Butterworth and Co. (Publishers) Ltd.



MO-0012

Adapted for testing purposes only from Alfa-Laval MAPX 210TGT-20 Separator

Instruction Book. © Alfa-Laval. Further reproduction prohibited without permission.

A

B

C

D

E

F

G

H

R

Q

O

N

M

L

I

J

K

P

S



MO-0029

Adapted for testing purposes only from Description of and Operating Instructions

for Sulzer Diesel Engines, RND-M. © Sulzer Brothers Limited.

Further reproduction prohibited without permission.

A

B

C

D



3/11/2015

MO-0046

Adapted for testing purposes only from STINSON, Diesel Engineering Handbook,

12th

Edition. Copyright © 1981 Business Journals, Inc.


II

III

I



4/15/2015

MO-0057

Adapted for testing purposes only from GUNTHER, Lubrication.

Copyright © 1971 by Raymond C. Gunther.


A

B

D

C



4/21/2015

MO-0058

Adapted for testing purposes only from HARRINGTON, Marine Engineering. Copyright

© 1992 by The Society of Naval Architects and Marine Engineers. Further reproduction

prohibited without permission. of 33 Q610 Motor Plants


7/23/2015

MO-0061

Adapted for testing purposes only from KATES/LUCK, Diesel and High Compression

Gas Engines, 3rd

edition

Copyright © 1974 by American Technical Society



7/28/2015

MO-0062

Adapted for testing purposes only from Sulzer, Description of and Operating

Instructions for Sulzer Diesel Engines RND-M

Copyright © Sulzer Brothers Limited




5/17/2017

MO-0077

Adapted for testing purposes only from HARRINGTON, Marine Engineering

Copyright © 1992 by The Society of Naval Architects and Marine Engineers

Further reproduction prohibited without permission of 33 Q610 Motor Plants


7/14/2016

MO-0080

Adapted for testing purposes only from Exhaust-Gas Turbocharger VTR 250 W3P,

Instructions For Operation and Maintenance

Copyright © BBC Brown, Boveri & Company, Ltd.

Further reproduction prohibited without permission



7/15/2016

MO-0082

Adapted for testing purposes only from KATES/LUCK, Diesel and

High Compression Gas Engines, 3rd

edition

Copyright © 1974 by American Technical Society



7/21/2016

MO-0086

Adapted for testing purposes only from LUFKIN, Marine Gears, Catalog No. MG-77

Copyright © Lufkin Industries, Inc



10/3/2016

MO-0120

Adapted for testing purposes only from Sulzer, Description of and

Operating Instructions for Sulzer Diesel Engines RND-M

Copyright © Sulzer Brothers Limited




9/30/2016

MO-0122

Adapted for testing purposes only from EMD 645E9

Turbocharged Engine Maintenance Manual

Copyright © 1973 Electro-Motive Division, General Motors.




10/20/2016

MO-0128

Adapted for testing purposes only

Further reproduction prohibited without permission of 33 Q610 Motor Plants

national maritime center - dco.uscg. · pdf filenational maritime center ... the function of...

Documents