- Lubricating system for diesel engines are usually designed to initially provide lube oil to the engine
a)camshaft bearings
b)main bearings
c)piston crowns
d)cylinder walls
Answer-B
- Mechanical lubricators for diesel engine cylinders are usually small reciprocating pumps which are
a)operated manually once each hour
b)operated until the engine has started
c)placed into operation only at maximum load
d)adjustable to meet lubrication requirements
Answer-D
- Shacker, circulation, and spray are the three general methods used in
a)pre-injection fuel oil treatment
b)lube oil filtration
c)fuel oil purification
d)piston cooling
Answer-D
- Fuel injector nozzles are usually of the multi-orifice type with the number and placement of the holes arranged according to the
a)type of piston rings
b)pressure of the fuel system
c)size of the pump plunger spring
d)design of the combustion chamber
Answer-D
- What is the crank angle between any two crank throws in the firing order of a four-stroke/cycle, in line, eight cylinder diesel engine?
a)45 degree
b)60 degree
c)90 degree
d)100 degree
Answer-C
- The main reason counterweights are added to crankshafts is to
a)reduce piston side thrust
b)reduce crankshaft end thrust
c)provide uniform loading and wear of main bearings
d)increase the strength of the crank webs
Answer-C
- A viscous damper, as used on a marine diesel, is a sealed precision built device which dampens the torsional vibrations in the
a)camshaft
b)flywheel
c)crankshaft
d)thrust shaft
Answer-C
- A crankshaft whose center of gravity coincides with its center line is said to be
a)dynamically balanced
b)statically balanced
c)counter balanced
d)resonantly balanced
Answer-B
- The possibility of damage from operating a diesel engine at critical speeds is reduced by the use of
a)an isochronous governor
b)elastic engine mounts
c)a vibration damper
d)a cast iron bed plate with good flexible qualities
Answer-C
- In a diesel engine lube oil system, which of the following parts should be lubricated first?
a)Camshaft bearings
b)Main bearings
c)Piston crowns
d)Cylinder walls
Answer-B
- When fuel oil heaters are required for engine operation,
a) each heater shall have the capacity to supply the main engine at full power
b)at least two heaters of approximately equal size are to be installed
c)the system shall be designed to permit series or parallel operation
d)none of the above
Answer-B
- An advantage of aluminium pistons compared to cast iron pistons is:
a)greater high temperature strength
b)better heat conductivity
c)greater weight per cubic cm
d)increased resistance to wear
Answer-B
- Which engine component increases air density and helps to improve engine operating efficiency?
a)impeller
b)compressor
c)aftercooler
d)exhaust diffuser
Answer-C
- An electric heater built into the cylinder water jacket would be used to
a)raise lube oil viscosity for easier starting in cold weather
b)increase air inlet temperature
c)increase compression ratio
d)increase water temperature for easier starting in cold weather
Answer-D
- Which is found with both mechanical and hydraulic governors?
a)direct linkage between the ball head and fuel rack
b)a servomotor
c)a compensating device
d)flyweights
Answer-D
- Which of the following design features will reduce the possibility of overheating the top compression rings of a cast iron piston?
a)The top ring is located as close to the piston as possible
b)The inside surface of the piston head is rounded into the ring belt
c)A nickel-bearing insert is cast into the top ring groove
d)A heat dam design is sometimes used in the piston head
Answer-D
- The purpose of heat dam used in some diesel engine cast iron pistons is to
a)concentrate all heat in the piston crown
b)increase the distance of travel for heat from the crown to the top ring groove
c)ensure that all heat in the piston crowns is conducted to the top ring
d)provide a short direct path for heat to flow from the crown to the top ring
Answer-B
- Valves used in diesel engine fuel oil pressure piping are to be
a)installed to close against flow
b)solenoid released upon the failure of engine lubrication
c)either of the gate or globe valve type
d)forge constructed under the approval of the Marine Inspector
Answer-A
- Cast iron pistons used in large propulsion engines are constructed with
a)no taper whatsoever
b)the skirt being tapered and smaller than the crown
c)the skirt being tapered and larger than the crown
d)the crown being tapered and smaller than the skirt
Answer-D
- The diameter of a piston is usually less at the crown than at the skirt, in order to
a)facilitate the installation of piston rings
b)allow for the expansion of the piston during operation
c)prevent crankcase vapors from entering the combustion chamber
d)reduce wearing of the upper cylinder liner
Answer-B
- Which of the following manufacturing methods is recommended for diesel engine fuel injection line piping?
a)Cold rolled
b)Electric resistance welded
c)Seamless drawn
d)Straight seam
Answer-C
- Exhaust pipes of multiple engine installations are not to be interconnected, but are to be run separately to the atmosphere
a)unless arranged to prevent the return of gases to an idle engine
b)to a point not lower than the highest load line
c)at a location segregated from other ventilation systems
d)and shall be protected by a rain guard or similar device
Answer-A
- Which of the bearing types listed is most commonly used in smaller vessel main propulsion reduction gears as thrust bearings?
a)ball bearings
b)poured bearings
c)sleeved bearings
d)tapered roller bearings
Answer-D
- The main reason for using bimetallic piston rings is to
a)increase engine thermal efficiency
b)reduce specific fuel consumption
c)reduce the probability of ring fracture
d)allow for ring expansion
Answer-C
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