|
B |
Why will a turbocharged
diesel engine produce black smoke if excessive additional load is applied
too quickly? |
Exhaust energy
would draw excess air. |
The inertia of
the turbocharger rotor causes a time lag which delays the turbocharger speed
increase. |
Exhaust gas pumping
losses are increased due to turbine windage. |
Exhaust gas back
pressure falls slightly due to increased nozzle action. |
|
C |
After cooling
of a turbocharged diesel engine will result in __________. |
higher torque
but lower brake horsepower |
lower torque but
higher brake horsepower |
higher torque
and higher brake horsepower |
lower torque and
lower brake horsepower |
|
B |
The process of
scavenging a two-stroke/cycle diesel engine serves to __________. |
improve fuel flow
volume |
cool the exhaust
valves |
reduce the intake
air charge density |
increase the temperature
of exhaust gases |
|
D |
When would the
available energy of the exhaust gases of a two-stroke/cycle diesel engine
be insufficient to drive an exhaust gas turbocharger, resulting in the incorrect
amount of air for combustion? |
During operation
at low load and speed |
During operation
at rated speed, but low power output |
During acceleration |
All of the above. |
|
C |
The average exhaust
temperature of a two-stroke/cycle diesel engine with a turbine-driven supercharger
is lower than a similar four-stroke/cycle diesel engine at equal loads because
__________. |
two-stroke/cycle
diesel engines have a higher M.E.P. than four-stroke/cycle diesel engines |
four-stroke/cycle
diesel engine exhaust is cooled by scavenging air |
two-stroke/cycle
diesel engines have a lower M.E.P. than four-stroke/cycle diesel engines |
the opening of
the two-stroke/cycle diesel exhaust ports or valves occurs much later than
in four-stroke/cycle diesel engines |
|
A |
Clearance volume
scavenging in a turbocharged, four-stroke/cycle diesel engine is accomplished
__________. |
during the valve
overlap period |
with only the
exhaust valve open |
at a pressure
below atmospheric |
without cooling
the cylinders or pistons |
|
D |
In a turbocharger,
inlet air velocity is increased in the __________. |
inlet nozzle ring |
stationary diffuser
passages |
compressor outlet
volute |
rotating impeller
vanes |
|
D |
Regarding the
turbocharger shown in the illustration, the part labeled "B" would
be attached to the __________. Illustration MO-0080 |
nozzle ring |
silencer outlet |
exhaust manifold |
after cooler inlet |
|
D |
Which of the following
statements is correct regarding a turbocharged four-stroke cycle diesel-
generator? |
At zero load the
intake manifold pressure is greater than the exhaust manifold pressure. |
At full load the
intake manifold pressure and exhaust manifold pressure are equal. |
At full load the
intake manifold pressure is less than the exhaust manifold pressure. |
At full load the
intake manifold pressure is greater than the exhaust manifold pressure. |
|
C |
Large, two-stroke/cycle,
main propulsion, diesel engine cylinders can be successfully pressure charged
during normal operation, by using the __________. |
exhaust gas temperature
system |
exhaust load system |
constant or pulse
pressure system |
constant volume
system |
|
C |
Which of the turbocharging
systems listed operates with the least average back pressure in the exhaust
manifold? |
Constant volume |
Constant pressure |
Pulse pressure |
Radial flow |
|
A |
Which of the turbocharging
methods listed directs the exhaust gases to the turbine at fairly uniform
velocity and pressure? |
Constant pressure |
Pulse pressure |
Constant velocity |
Axial flow |
|
A |
In a Roots-type
rotary blower, the volume of air delivered is directly proportional to __________. |
engine speed |
engine load |
brake horsepower |
brake specific
fuel consumption |
|
B |
Which of the designs
listed will keep the lobes from making contact in a Roots-type blower? |
Drive chain |
Blower timing
gears |
Air trapped between
blower lobes |
Oil filter between
blower lobes |
|
A |
In a two cycle
diesel engine, a Roots type blower is usually __________. |
gear driven by
the engine |
driven by an exhaust
gas turbine |
actuated by the
intake valves |
driven by separate
motor |
|
C |
Which of the operating
characteristics listed is correct concerning the blower shown in the illustration?
Illustration MO-0082 |
Each of the lobes
are in constant contact with each other |
Air delivery is
inversely proportional to engine speed. |
Air delivery is
approximately proportional to engine speed. |
The blower is
driven by engine exhaust gases |
|
D |
The power consumed
during the scavenging process of a diesel engine is known as the __________. |
compression loss |
valve loss |
back pressure
loss |
pumping loss |
|
C |
Air scavenging
of the cylinder shown in the illustration begins between figures __________.
Illustration MO-0025 |
4 and 5 |
2 and 3 |
3 and 4 |
5 and 6 |
|
A |
During the valve
overlap period, the exhaust pressure of a turbocharged, four-stroke cycle
diesel engine must be less than the intake manifold pressure to ensure __________. |
effective cylinder
scavenging and cooling |
constant pressure
from the turbochargers |
cooler operation
of the exhaust system |
effective constant
pressure for turbocharger operation |
|
A |
A loop or cross
scavenged engine utilizes the motion of its pistons and a turbocharger to
provide scavenging air. Which of the listed mechanical designs prevents
the air under the pistons from being pumped back through the scavenge ports
during the piston power stroke? |
Length of the
piston skirt |
Masked intake
ports |
Lower liner seals |
Positive pressure
from the blower |
|
B |
The diesel engine
shown in the illustration, is provided with an auxiliary blower to __________.
Illustration MO-0003 |
increase scavenge
air pressure at full load |
provide scavenge
air pressure at low load |
maintain a vacuum
on the crankcase |
maintain a positive
pressure on the crankcase |
|
D |
A diesel generator
governor is hunting. After changing the oil, the governor is flushed and
the compensation needle valve is adjusted, but the hunting persists. You
should NOW __________. |
check air intake
manifold pressure |
calibrate the
fuel pump rack settings |
set the speed
droop adjustment to zero |
carefully check
for binding in the governor linkage |
|
B |
The most common
contaminate of governor hydraulic fluid is __________. |
moisture |
dirt |
acid |
air |
|
C |
If a hydraulic
governor has been refilled with oil, the engine should be operated until
it reaches normal temperature, then the air should be purged, and the __________. |
rack position
should be adjusted |
compensating needle
valve should be opened fully |
compensating needle
valve should be adjusted to stabilize operation |
speed limiting
device should be adjusted |
|
D |
Adjustments to
the compensating needle valve in a hydraulic governor should be made with
the engine at __________. |
maximum power
at a normal load |
maximum power
and load under normal conditions |
half speed and
normal temperature |
normal operating
temperature without a load |
|
A |
Sacrificial zinc
anodes are used on the saltwater side of diesel engine heat exchangers to
__________. |
reduce electrolytic
action on heat exchanger metals |
provide a protective
coating on heat exchanger surfaces |
keep heat transfer
surfaces shiny and clean |
prevent rapid
accumulation of marine growth |
|
C |
When the timing
gear backlash for a Roots-type blower has become excessive, the problem
is properly repaired by __________. |
renewing the drive
gear |
renewing the driven
gear |
renewing both
driving and driven gears as a set |
shimming and pinning
the gears with proper backlash |
|
A |
Which of the listed
effects would mixtures of ethylene glycol and phosphate compounds have on
the metal surfaces of the cooling system of a diesel engine? |
Protects metallic
surfaces from corrosion and the coolant from freezing |
Tends to increase
corrosion |
Increases the
rate of heat transfer |
Retards the flow
of cooling water |
|
A |
Ethylene glycol,
when used as a coolant in a closed cooling system for a diesel engine, is
more advantageous than untreated raw water because it __________. |
has a lower freezing
point and higher boiling point |
provides a constant
pH below 7 |
provides better
vapor-phase cooling |
has a higher freezing
point and a lower boiling point |
|
B |
If the coolant
temperature is too low as it passes through internally cooled fuel injectors,
the injectors can be damaged by __________. |
water condensation
in the fuel |
corrosion of the
nozzle tip |
decrease in fuel
oil viscosity |
inadequate lubrication
of the needle valve |
|
A |
When installing
the bearing cap on the device shown in the illustration, which of the precautions
listed must be observed? Illustration MO-0121 |
Once the bearing
cap is properly torqued, measure the end gap dimensions to ascertain even
tightening of the cap. |
If the device
is covered with abrasive material or contaminates, the unit may be reassembled,
provided an abnormal method of reassembly is followed. |
Prior to installing
the cap, position the thrust shoes in their proper locations. |
After applying
antiseize to the external threads, torque one side at a time to the appropriate
values using a quality torque wrench. |
|
C |
What is the normal
bearing clearance permitted at the horizontal axis of the shaft for the
bearing shown in the illustration? Illustration MO-0121 |
The clearance
is determined by the thickness of the hydrodynamic wedge formed and is not
usually measured while underway. |
The tolerances
established are dependent on machining processes used and will vary
amongst manufacturers. |
The normal play
on both sides of the shaft will be one tenth of a millimeter. |
The clearance
on one side of the shaft at the axis will be one twentieth of a millimeter. |
|
B |
After following
the prescribed procedures to measure the thrust bearing clearance shown
in the illustration, the distance "F" is determined to be 200
mm, and 'f1' is 2.3 mm. Which of the following statements describes the
condition indicated by these dimensions? Illustration MO-0121 |
These dimensions
indicate the presence of flourishing marks on the thrust shoes; the marks
becoming visible as the distance at 'f1' increases. |
It is possible
for the shaft to move axially 2.3 mm during astern operation and relates
to an excess movement of 1.3 mm, 0.3 mm beyond the maximum worn play. |
The loading ratio,
or shaft diameter divided by collar surface area is within 2.7 : 1. |
The total active
thrust area is 202.3 mm, well within the standards set forth by the GSMA
(German Society for Machining Accuracy). |
|
B |
Because of the
close tolerances used in diesel engine fuel oil pumps, a worn plunger requires
__________. |
grinding the spare
plunger to the barrel |
replacing the
plunger and the barrel |
highly polishing
both the plunger and barrel |
replacing plunger
only |
|
A |
When a nozzle
tester is being used to test a "closed" type fuel injection nozzle,
a clogged nozzle orifice will be indicated by a __________. |
distorted spray
pattern |
chattering sound
when the nozzle closes |
squealing sound
midway in the pump stroke |
popping sound
when the nozzle opens |
|
A |
Which of the fuel
nozzles listed requires the LEAST maintenance? |
Pintle |
Single hole |
Multi-hole |
Open |
|
A |
When running a
large, dual fuel, main propulsion diesel engine on heavy fuel, which of
the following precautions should be observed when switching from heavy fuel
oil to diesel oil? |
The temperature
of the fuel from the preheater should be gradually reduced after switching
over the three-way valve. |
The diesel oil
must never be allowed to mix with the heavy fuel. |
The heating steam
to the preheater should be increased as soon as the diesel fuel passes through
the three-way valve. |
The heating steam
must be secured before the diesel oil passes through the three-way valve. |
|
B |
Air is normally
bled from a diesel engine fuel system by __________. |
blowing down the
air tanks |
loosening the
compression nuts at the injectors |
changing fuel
filters |
pumping down the
day tanks |
|
B |
The spray holes
in diesel engine fuel valves should be cleaned using carbon solvent and
__________. |
diesel fuel |
a special cleaning
wire |
a copper wire
brush |
a shaved wooden
dowel |
|
B |
If the compression
rings on a diesel engine piston become stuck in the ring groove, the cause
may be due to __________. |
excessive ring
action |
excessive ring
temperature |
improper ring
rotation |
excessive ring
face wear
|
|
A |
The insertion
of shims between the foot of a marine type connecting rod and a bearing
box would result in __________. |
increased compression
ratio |
decreased compression
ratio |
increased bearing
clearance |
decreased bearing
clearance |
|
D |
After a long period
of operation, a wear ridge, caused by piston ring action, will develop near
the top of the cylinder liner. This ridge must be removed during maintenance
in order to prevent __________. |
excessive ring
wear during the seating period |
excessive lubrication
of the top ring |
improper coating
of lubrication on the cylinder wall |
breaking of the
rings, ring lands, or both during piston removal |
|
D |
When a piston
is removed from a diesel engine for maintenance, the piston should be examined
for __________. |
cracks and burned
spots |
scoring |
gummy deposits
and sticking rings |
All of the above. |
|
D |
Excessive side
clearance between a piston ring and its groove will cause the ring to __________. |
expand excessively
under operating temperatures |
scuff the cylinder
liner excessively |
hammer the piston
land above the ring |
hammer the piston
land below the ring |
|
D |
After removing
the bowl hood of the device shown in the illustration, excessive quantities
of sludge are visible. Which of the following statements represents the
approach to rectify
the situation? Illustration MO-0112
|
Disassemble the
entire unit, clean all components, replace all defective discs and use the
proper lubricant where required. |
Steam clean the
components in place, check for proper alignment, using the match marks provided,
reassemble and restart the unit. |
Remove only the
disc stack, separate all the discs, clean with steel wool and solvent, replace
the disc stack ensuring it is located by use of the dowel pin shown. |
Disassemble the
entire unit, clean all components, replace any defective gaskets and use
the proper lubricants where required. |
|
C |
When tightening
the lock ring "G" of the device shown in the illustration, two
events are simultaneously accomplished. Which of the following statements
represents these events? Illustration MO-0112 |
The lock ring
insures proper contact between the bowl top and the sliding bowl bottom,
in addition to compressing the disc stack. |
The lock ring
forces the disc stack onto the spindle, providing a positive means of rotation
and locating the bowl top to seal the separation chamber. |
When tightened,
the lock ring allows for movement of the sliding piston and positions the
sliding piston within the bowl bottom. |
The lock ring
insures proper positioning of the disc stack and maintains a positive contact
of the bowl top and bowl bottom. |
|
D |
Before any auxiliary
diesel engine hydraulic starting system is opened for servicing or repair,
you must __________. |
place all control
levers in the 'HOLD' position |
ensure that the
hydraulic fluid reservoir is full |
block all hydraulic
hoses using high pressure covers |
bleed off all
hydraulic pressure from the system |
|
B |
The service life
of a worn aluminum piston for an auxiliary diesel, for which no spares are
readily available, can be extended by __________. |
turning down the
piston skirt to concentric values |
knurling the piston
skirt surface |
building up the
piston skirt with a liquid epoxy material and then remachining |
increasing the
dimensions of the ring land grooves |
|
A |
In an auxiliary
diesel engine, one reason for knurling the piston skirt is to __________. |
improve skirt
lubrication |
allow for heat
expansion |
transmit forces
evenly |
improve the piston
seal |
|
B |
Decreasing the
exhaust valve clearance of a diesel engine will cause the exhaust valve
to open __________. |
earlier and have
less lift |
earlier and remain
open longer |
later and have
greater lift |
later and have
less duration |
|
D |
When inspecting
the valve mechanism shown in the illustration, normal maintenance would
include __________. Illustration MO-0074 |
mechanically adjusting
the valve at point "D" |
mechanically adjusting
the valve at point "E" |
changing the tappet
clearance as measured between points "A" and "B" |
measuring the
cold valve clearance between components "C" and "D" |
|
D |
Which of the following
statements would apply when checking the valve clearance of the unit shown
in the illustration? Illustration MO-0074 |
The valve is mechanically
adjusted at point "D". |
The valve is mechanically
adjusted at point "E". |
Tappet clearance
is measured between points "A" and "B". |
Cold valve clearance
is measured between components "C" and "D". |
|
C |
If a tube ruptures
in a water-tube auxiliary boiler due to low water, you should __________. |
secure the fires
and maintain feed water to boiler to keep up the water level |
not secure the
fires until water level falls out of sight in the gage glass |
secure both the
fires and the feed inlet valve |
secure the fires
when the pressure drops to 50% of the maximum allowable working pressure |
|
D |
What is the best
way of stopping an over speeding diesel engine? |
Disconnect the
battery cables from the starting motor. |
Drain the hydraulic
fluid from the governor sump. |
Block the flow
of cooling air to the radiator. |
Secure the fuel
supply and block the air intake |
|
C |
If a crankcase
explosion due to a hot spot were to occur, the size of the explosion is
dependent on which of the following? |
The temperature
of the hotspot in the crankcase. |
The amount of
debris in the oil in the crankcase. |
The ratio of oil
mist to air in the crankcase. |
The amount of
water in the oil in the crankcase. |
|
D |
Which of the following
oil mist to air ratios would most likely lead to the most severe crankcase
explosion? |
12-15% by volume. |
2-3% by volume. |
9-10% by volume. |
5-7% by volume. |
|
A |
In the event of
a crankcase rich oil mist to air mixture explosion, where the doors are
blown off the engine, which of the following may occur after the initial
explosion? |
A secondary explosion
as air is drawn back into the crankcase. |
The crankcase
pressure will remain higher than normal. |
The engine will
over speed. |
Any crankcase
fire will be self extinguished. |
|
D |
After stopping
a diesel engine with a high main bearing temperature, what is the time one
needs to wait before a diesel engine crankcase can be opened? |
Not less than
120 minutes. |
Not less than
15 minutes. |
Not less than
60 minutes. |
Not less than
30 minutes. |
|
B |
Which of the following
is one of the ways to prevent a scavenging fire on a slow speed diesel engine? |
Prevent air from
entering the scavenging space. |
Keep the scavenging
space clean and free of oil. |
Shut down the
engine if the crankcase mist detector alarm sounds. |
Monitor the main
bearing temperatures. |
|
A |
Oil in a scavenging
air space on a slow speed diesel engine can be ignited by which of the following? |
Excessive piston
ring blow by. |
Burned exhaust
valve seat. |
Hot main bearing. |
Early fuel injection. |
|
B |
If a scavenging
air space fire occurs on a slow speed diesel engine and the engine is stopped,
which of the following should be done to prevent distortion due to heat? |
Let the fire burn
out naturally. |
Engage and turn
the engine with the jacking gear. |
Open the engine
to inspect the hot area. |
Use CO2 to extinguish
the fire and cool the engine. |
|
A |
Which of the following
would indicate a scavenging air fire in a slow speed diesel engine? |
An increase in
jacket water temperature in the area local to the fire. |
A low main lube
oil pressure alarm. |
An oil mist detector
alarm. |
An increase in
main bearing temperature in the area local to the fire. |
|
C |
If a diesel engine
were running at 20% overload with a smoky exhaust, you should __________. |
stop the engine
immediately to prevent damage |
increase lube
oil pressure |
slow the engine
allowing it to gradually cool |
decrease the cooling
water temperature to the water jacket |
|
C |
A main propulsion
diesel engine is normally shutdown by __________. |
shutting off the
air supply |
over speeding
the engine |
securing the fuel
supply |
securing the ignition
system |
|
C |
The over speeding
of the diesel engine driving an electric generator could cause __________. |
low voltage trip
to trip |
reverse power
trip to trip |
damage to the
field windings |
excessive exhaust
temperatures |
|
C |
A normally operating
diesel engine is shutdown by __________. |
shutting off the
air supply |
over speeding
the engine |
securing the fuel
supply |
securing the ignition
system |
|
B |
Load control on
a diesel engine is accomplished by __________. |
regulating the
speed of the turbocharger |
regulating the
amount of fuel admitted to the engine |
regulating the
speed of the fuel oil transfer pump |
changing engine
timing |
|
D |
Diesel engine
automated control systems may utilize sensing devices of dual function,
with sensing ranges providing both alarm and engine shut down capability.
Which of the key points listed would only require an alarm sensor? |
Lube oil pressure
and temperature |
Jacket water pressure
and temperature |
Engine over speed |
Lube oil sump
level |
|
D |
Which of the following
statements describes the operation of the circuit shown in the illustration?
Illustration MO-0114 |
The output of "2"
will always be less than the input at "1" by 0.35 bar (35 kPa),
to prevent engine damage due to operation in the critical speed range.
o |
A gradual rise
of the input signal to "1" will cause a multiple stepped output
from "2" proportional to the input signal.
o |
The output signal
from "2" will be equal to the set point of '17A' only when the
input is less than the set point of '17B', permitting the transition signal
to become modulated. |
The output from "2"
is equal to the input to "1" except when the input of "1"
is between the set points of '17A' and '17B', when it will remain at the
value of '17A'. |
|
D |
The device represented
by the symbol "B" in the illustration is used to __________. Illustration
MO-0115 |
remove all moisture
from the system
o |
lubricate the
air supply |
reduce the temperature
of the air supply as a result of the heat of compression |
remove most contaminants
present in the air supply |
|
C |
The pneumatic
circuit shown in the illustration is part of a control system used with
large low speed diesel engines. The arrangement may be used to control __________.
Illustration MO-0118 |
bridge tachometer
variations |
the proportional
offset of the throttle signal |
main engine speed
o |
emergency clutching
operations |
|
D |
The symbol with
the output 'ee' shown in the illustration, is properly called a blocking
valve. Which of the following statements describes its function when incorporated
into a slow speed diesel engine pneumatic control circuit? Illustration
MO-0116 |
The device is
used to interrupt the control signal to port "J" of the air start
distributor shown in illustration MO-0053.
|
The blocking device
prevents direct hydraulic flow from operating the reversing mechanism.
|
All speed signals
emanating from the throttle lever are diminished by half due to the blocking
effect of this valve. |
The device is
used to interrupt the pneumatic signal to port "A" of the distributor
shown in illustration MO-0053. |
|
A |
A water jacket
is placed around the exhaust manifolds of propulsion diesel engines to __________. |
reduce heat radiation
to the engine room |
aid in preventing
turbocharger overheating |
condense and drain
moisture from exhaust gases |
dampen exhaust
gas pulsations in the manifold |
|
D |
In the engine
shown in the illustration, the part labeled 'W' is cooled by __________.
Illustration MO-0003 |
lube oil |
convection |
air |
seawater |
|
C |
The diesel engine
shown in the illustration, which of the lettered parts listed is cooled
by sea water? Illustration MO-0003 |
P |
Y |
W |
Q |
|
D |
The large, slow-speed,
main propulsion diesel engine shown in the illustration, the part labeled
'B' contains __________. Illustration MO-0003 |
exhaust gas |
oil |
diesel oil |
water |
|
C |
The outlet from
an expansion tank of a closed fresh water cooling system should be piped
to the __________. |
cylinder jacket
inlet main |
heat exchanger
inlet connection |
jacket water pump
suction line |
cylinder head
water outlet header |
|
D |
Which set of valves
will be opened intentionally to remove heat from the main engine jacket
cooling water system shown in the illustration? Illustration MO-0111 |
"G"
and "H", "E" and "F" |
"B"
and "D", "L" and "M" |
"J"
and "K", "G" and "H" |
"A"
and "C", "L" and "M" |
|
B |
What is the function
of the device labeled "3" shown in the illustration? Illustration
MO-0111 |
The device specifically
serves to remove the latent heat of vaporization from the jacket water. |
The cooler removes
sensible heat from the jacket water. |
The heat exchanger
serves to heat the jacket water during cold water operation. |
The jacket water
cooler is used to raise the temperature of the sea water flowing through
it. |
|
A |
What is the function
of the item "7" shown in the illustration? Illustration MO-0111 |
This jacket water
pump circulates fresh water throughout the engine cooling and distiller
heating systems. |
This circulating
salt water pump will supply feed water for the operation of the distiller. |
This jacket water
pump supplies the distiller with sea water feed while also powering the
eductors. |
This jacket water
pump circulates salt water through the jacket water cooling system to provide
engine cooling. |
|
C |
Fuel injectors
used in heavy fuel oil systems are usually provided with cooling to reduce
__________. |
cold corrosion
of the nozzles |
fuel viscosity
for better atomization |
carbon accumulation
on the nozzles |
fuel detonation
in the cylinders |
|
B |
The operation
of the lube oil cooler, shown in the illustration as item #4, will be characterized
by which of the following statements? Illustration MO-0111 |
The temperature
of the lube oil entering the cooler will decrease whenever the distiller
is on line. |
The temperature
of the sea water entering the cooler will be higher when operating with
the distiller on line. |
The pressure of
the lube oil to the cooler will increase whenever the distiller is on line. |
The pressure of
the sea water to the lube oil cooler will increase with the distiller on
line. |
|
D |
What is the primary
function of item '15' shown in the illustration? Illustration MO-0111 |
It removes the
vapor condensed in area "23". |
It is the chemical
cleaning pump used in conjunction with valve "12". |
It is used to
empty the evaporator section when there is tube leakage while the unit is
secured. |
It removes the
distillate condensed in area "24". |
|
D |
Which of the following
statements represents the two major functions provided by the item labeled "20"
shown in the illustration? Illustration MO-0111 |
The pump supplies
the motive force to the ejectors and removes the excess distillate. |
The pump is used
to drain the shell when the unit is secured, in addition to powering the
ejectors. |
The pump provides
for venting of associated equipment while also powering the ejectors. |
The pump supplies
the motive fluid to the ejectors in addition to supplying the feed water
to the distiller. |
|
D |
The items labeled "21"
and "22", shown in the illustration are used to remove __________.
Illustration MO-0111 |
distillate and
non-condensable gases |
non-condensable
gases from two separate sections of the distiller |
brine and jacket
water from the condenser |
non-condensable
gases and brine |
|
A |
What occurs within
the tubes of the device labeled "23" shown in the illustration?
Illustration MO-0111 |
The feed water
flowing through the inside of the tubes is being heated by the jacket water
on the outside of the tubes. |
The heat from
the jacket water passing within the tubes is being transferred to the feed
water on the outside of the tubes. |
The heat of combustion
from the engine is being transferred azeotropically, adding latent heat
to the entering jacket water. |
The heat being
transferred is subliminal, therefore expansion is taking place within the
tubes. |
|
C |
Which of the following
statements describes what will occur to the volume of water vapor as it
is exposed to the lower temperatures existing in the device labeled "24"
shown in the illustration? Illustration MO-0111 |
The volume is
increased as condensation occurs at the tube surfaces. |
The volume will
increase if the valve labeled "J" is opened excessively, resulting
in an
increase of the distiller absolute
pressure. |
The volume is
greatly reduced, contributing to condensation within the condenser. |
The latent heat
of condensation is removed causing the volume to increase. |
|
C |
Device "27"
shown in the illustration is used to __________. Illustration MO-0111 |
purge the unit
of non-condensable gases |
add de-scaling
chemicals as needed |
regulate maximum
vacuum during normal operation |
relieve excess
pressure |
|
D |
Which of the valve
arrangements listed would be correct for operating the distillation plant
shown in the illustration? Illustration MO-0111 |
Valves "C", "J", "K", "L", "M"
open, valves "A", "B", "D", and "H"
closed. |
Valves "H", "J", "K", "L", "M"
open, valve "D" closed. |
Valves "D", "H", "J", "K", "L", "M"
open, valves "I", "G", "F", and "E"
closed. |
Valves "J", "K", "L", "M"
open, valves "D" and "H" closed. |
|
C |
Excess brine accumulated
in the distiller, shown in the illustration, is removed during normal operation
by __________. Illustration MO-0111 |
the hydrokineter
labeled "21" |
opening the drain
valve located to the left of orifice "19" |
the continuous
action of ejector "22" |
orifice "19"
regulating the amount of feed water entering the distiller, thereby preventing
excess brine accumulation |
|
B |
During operation
which device listed removes air and non-condensable gases from the unit
shown in the illustration? Illustration MO-0111 |
"22" |
"21" |
"25" |
"27" |
|
A |
The graphic dotted
line between items "27", "12", "9", and "20",
shown in the illustration, is used to indicate the use of __________. Illustration
MO-0111 |
electrical conduits
and circuitry |
thermal venting
devices |
ambient venting
devices |
single wire controls |
|
B |
Excluding line
losses, how many distinct pressure drops will occur as sea water flows through
all the heat exchangers in the cooling system shown in the illustration?
Illustration MO-0111 |
6 |
5 |
3 |
4 |
|
C |
Which device is
used to prevent over pressurization of the illustrated distiller? Illustration
MO-0111 |
"19" |
"12" |
"26" |
"13" |
|
D |
Where is the latent
heat obtained to create vapor from the feed water in the illustrated distiller?
Illustration MO-0111 |
While it is in
contact with device "24". |
During its contact
period with heat exchanger "3". |
Only as it passes
through device "20". |
From having passed
through "23". |
|
A |
Which of the following
statements describes the approximate relation between the feed water entering
the unit shown in the illustration and brine being removed? Illustration
MO-0111 |
Seventy-five percent
of the feed water entering the unit is removed as brine. |
The brine will
be removed at a faster rate than feed water entering to prevent the possibility
of flooding. |
Twenty-five percent
of the feed water entering the device is removed as brine. |
The amount of
feed water entering the distiller is dependent upon the condition of device "7",
while the amount of brine leaving is dependent upon the condition of device "21". |
|
C |
Item "10"
shown in the illustration is used to __________. Illustration MO-0111 |
regulate flow
from the drain pump |
prevent damage
to device "9" by reducing turbulence |
direct the flow
from the distillate pump |
cancel the effects
of improper regulation developed by device "11" |
|
D |
Cooling water
pumps driven by direct-reversing diesel engines are usually __________. |
curved impeller
vane with concentric outlet |
straight impeller
vane with tangential housing |
curved impeller
vane with tangential outlet |
straight impeller
vane with concentric housing |
|
D |
As a general rule,
what would be the recommended operating water jacket outlet temperature
range for medium speed marine diesels set up with closed treated fresh water
cooling systems and fitted with vented expansion tanks? |
105° to 120°F |
135° to 150°F |
195° to 215°F |
165° to 180°F |
|
D |
In a diesel engine
closed freshwater cooling system, the cooling water pressure drop through
the engine is 10 psig, and the pressure drop through the heat exchanger
is 4 psig at maximum flow rates. The cooling water pump must produce a discharge
head of at least __________. |
4 psig |
6 psig |
28.7 psig |
15 psig |
|
A |
In a diesel engine
jacket water cooler, with sea water cooling the fresh water, the __________. |
jacket water pressure
should always be greater than the sea water pressure |
jacket water pressure
must always be less than the sea water pressure |
jacket water temperature
must always be less than 60°F |
sea water temperature
must never be warmer than 40°F |
|
D |
In a diesel engine
closed freshwater cooling system employing a radiator, proper water temperature
can be obtained by __________. |
passing cooling
water through a space heater |
passing cooling
water through the lube oil cooler |
piping exhaust
gases across the radiator front |
adjusting the
radiator louvers |
|
B |
If the jacket
water temperature rises rapidly above normal in a diesel engine, you should
FIRST __________. |
clean sea water
strainer |
reduce engine
load |
call the chief
engineer |
check thermostatic
valve |
|
C |
The expansion
tank for a diesel engine closed cooling system is designed to maintain a
constant head on the system and __________. |
provide an air
cushion |
reduce water turbulence |
allow for an increase
in water volume as the engine warms up |
reduce water temperature |
|
B |
The temperature
at which an adjustable bellows type thermostatic valve operates is determined
by __________. |
varying air loading
pressure to the bellows |
changing the spring
compression opposing the bellows |
changing the position
of the actuating bulb |
replacing the
bellows with a heavier spring |
|
D |
The thermostatic
valve in the illustration is used for controlling the coolant temperature
in a main propulsion diesel engine. Which of the following can be used to
verify proper valve operation with the valve disassembled? Illustration
MO-0079 |
Check spring compression
values against data given in manufacturer's handbook. |
Chemically analyze
contents of power pellet. |
Remove and examine
the contents of the power pellet. |
Place the thermostatic
element in a container of water at various operating temperatures and note
the movement of the valve stem. |
|
A |
Diesel engine
jacket water is used in the fresh water distillation process as the __________. |
means of heating
the feed water |
primary means
of producing a vacuum within the distiller |
coolant for the
distillate |
coolant for the
brine cooler |
|
A |
A three-way thermostatic
control valve regulates the diesel engine cooling water temperature by passing
a portion of the water __________. |
around the cooler |
around the engine |
overboard |
to the expansion
tank |
|
C |
What would be
considered a normal temperature increase between the inlet and outlet jacket
cooling water of a medium or high-speed diesel engine operating at normal
load? |
1° to 5°F |
50° to 100°F |
10° to 20°F |
5° to 10°F |
|
A |
Which operating
parameter may need to be decreased when running a large main propulsion
diesel engine at low load conditions? |
Cooling water
flow through after coolers |
Control air supply
pressure |
Lube oil temperature |
Fuel injection
pressure |
|
C |
Using a cooling
water temperature of 225°F (107.2°C), instead of 180°F (82.2°C) in an auxiliary
diesel engine, will __________. |
reduce the probability
of scale formation in the jacket cooling passages |
increase fuel
consumption per horsepower hour |
reduce the opportunity
for the formation of sulfuric acid in the cylinder bore exhaust passages |
allow for smaller
water passages within the engine |
|
B |
Which of the types
of reduction gearing listed is best suited for medium speed main propulsion
units? |
Hypoid |
Helical |
Cyclical |
Spur |
|
C |
In the reversing
reduction gear shown in the illustration, the forward and reverse main pinions
are in constant mesh with the main gear. This means the __________. Illustration
MO-0085 |
synchromesh coupling
will maintain transition torque control |
set that is clutched
in will rotate as idlers driven from the main gear |
idling gears rotate
in a direction opposite to their rotation when carrying load |
clutches are engaged
by a reduction in control air pressure |
|
B |
Reduction gear
casings are vented in order to __________. |
allow windage
to exist for cooling the gears |
avoid a buildup
of pressure within the gear case |
minimize lube
oil foaming within the case |
allow for axial
clearance between the gears |
|
B |
A diesel engine
with a full speed of 1000 RPM drives a propeller at 300 RPM. What is the
speed reduction ratio? |
0.3 to 1 |
3.33 to 1 |
33 to 1 |
300 to 1 |
|
D |
The main engine
thrust bearing shown in the illustration contains how many thrust shoes?
Illustration MO-0121 |
20 |
10 |
6 |
12 |
|
D |
How is lubrication
provided to the device shown in the illustration? Illustration MO-0120 |
The lubrication
system closely resembles the system used with standard line shaft bearings.
|
A separate system
containing oil under extremely high pressure is used due to its ability
to provide a high film strength.
o |
Only silicate
ester based synthetic oils have the capability and necessary characteristics
to be used in this type of application. |
The lube oil enters
through the supply pipes shown as #11 and eventually drains to the main
engine sump. |
|
D |
What type of bearing
is shown in the illustration? Illustration MO-0120 |
Axial/radial bearing
|
Collar bearing |
Kingsbury thrust
bearing |
Michell bearing |
|
B |
What prevents
the thrust bearing blocks shown in the illustration from rotating within
the housing? Illustration MO-0120 |
The bearing blocks
are massive and their weight provides sufficient force to prevent rotation. |
Found within the
thrust bearing cap or cover are extended protrusions to position the thrust
shoe segments and maintain minimum clearance.
|
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.
|
The thrust shoes
are dove-tailed into the collar. |
|
B |
Which of the couplings
listed is normally not repairable, and is usually replaced if completely
damaged? |
Flexible disk-ring
coupling |
Gear-type coupling |
Block and jaw
coupling |
Grid spring coupling |
|
D |
When installing
the bearing cap on the device shown in the illustration, which of the precautions
listed must be observed? Illustration MO-0121 |
Prior to installing
the cap, position the thrust shoes in their proper locations. |
If the device
is covered with abrasive material or contaminates, the unit may be reassembled,
provided an abnormal method of reassembly is followed. |
After applying
antiseize to the external threads, torque one side at a time to the appropriate
values using a quality torque wrench. |
Once the bearing
cap is properly torqued, measure the end gap dimensions to ascertain even
tightening of the cap. |
|
A |
What is the maximum
allowable clearance permitted between the bearing, shown in the illustration
and the shaft along its vertical axis? Illustration MO-0121 |
0.80 mm |
0.30 mm |
1.00 mm |
0.46 mm |
|
B |
What is the normal
bearing clearance permitted at the horizontal axis of the shaft for the
bearing shown in the illustration? Illustration MO-0121 |
The tolerances
established are dependent on machining processes used and will vary
amongst manufacturers. |
The normal play
on both sides of the shaft will be one tenth of a millimeter. |
The clearance
on one side of the shaft at the axis will be one twentieth of a millimeter. |
The clearance
is determined by the thickness of the hydrodynamic wedge formed and is not
usually measured while underway. |
|
C |
After following
the prescribed procedures to measure the thrust bearing clearance shown
in the illustration, the distance "F" is determined to be 200
mm, and 'f1' is 2.3 mm. Which of the following statements describes the
condition indicated by these dimensions? Illustration MO-0121 |
The loading ratio,
or shaft diameter divided by collar surface area is within 2.7 : 1. |
These dimensions
indicate the presence of flourishing marks on the thrust shoes; the marks
becoming visible as the distance at 'f1' increases. |
It is possible
for the shaft to move axially 2.3 mm during astern operation and relates
to an excess movement of 1.3 mm, 0.3 mm beyond the maximum worn play. |
The total active
thrust area is 202.3 mm, well within the standards set forth by the GSMA
(German Society for Machining Accuracy). |
|
D |
When an additional
load is applied to a diesel engine which is using an inadequately inflated
air bladder clutch unit, you can expect __________. |
excessive wear
on the thrust bearings |
pneumatic seizure |
chipped reduction
gear teeth |
overheating because
of slipping shoes |
|
C |
Misalignment of
the drive shaft and propeller shaft flanges can be detected by using a dial
indicator or __________. |
inside micrometer |
sighting device |
feeler gage |
adjustable trammel |
|
C |
The gear drive,
shown in the illustration, can have the backlash determined best by using
a __________. Illustration MO-0091 |
lead wire |
red dye indicator |
feeler gauge |
lash indicator |
|
B |
The thrust bearing
shown in the illustration has over eight years of ahead running time. Measurements
show "i1" is 4 mm and "i2" is 1mm. Which of the following
conditions is indicated and what steps should be taken, if any? Illustration
MO-0121 |
The stops in which
the thrust bearing block rides are worn, and it is necessary to return these
to their original specifications. |
No appreciable
wear has occurred, and the proper maintenance procedures should continue
to be followed. |
A wear rate of
1.6 mm per year is excessive and requires immediate assistance from the
manufacturer's field support. |
A wear rate of
1.6 mm per year occurred. Although not excessive, this condition may require
more frequent monitoring. |
|
D |
The power consumed
during the scavenging process of a diesel engine is known as the __________. |
compression loss |
valve loss |
back pressure
loss |
pumping loss |
|
B |
The exhaust system
for a turbocharged diesel engine functions to __________. |
power the after
coolers |
power the turbocharger |
reduce the cylinder
scavenge effect |
cool the turbocharger |
|
C |
Exhaust pipes
for separate main propulsion diesel engines can be combined only when __________. |
space limitations
prevent separately run pipes |
the engines are
small auxiliary units |
they are arranged
to prevent gas backflow to each engine |
a waste heat boiler
is installed |
|
B |
One of the factors
limiting the amount of load which can be put on a modern marine diesel engine
is the __________. |
governor sensitivity |
exhaust temperature |
fuel injection
pressure |
speed of the cam
shaft |
|
B |
In a diesel engine
exhaust system, the cooling of the exhaust gases below their dew point,
will result in __________. |
increased engine
back pressure |
sulfuric acid
corrosion |
surface pitting
of the turbocharger compressor blades |
moisture impingement
on the turbocharger compressor blading |
|
D |
The most common
instrument used to measure diesel engine exhaust pressure is the __________. |
pyrometer |
bourdon gauge |
pneumercator |
manometer |
|
C |
Which of the diesel
engine exhaust mufflers listed is usually equipped with a spark arrestor? |
A wet-type exhaust
muffler |
A constant pressure
muffler |
A dry-type exhaust
muffler |
A constant velocity
muffler |
|
C |
Diesel engines
driving alternators operating in parallel must maintain a set frequency
regardless of load changes. The governor characteristic used to accomplish
this is known as __________. |
actuation |
sensitivity |
compensation |
promptness |
|
D |
The device used
to limit engine torque at various engine speeds is called a __________. |
speed limiting
governor |
variable speed
governor |
constant speed
governor |
load limiting
governor |
|
C |
Sensitivity for
a diesel engine governor is described as the __________. |
governor's speed
droop response to variations in engine load |
ability to maintain
desired engine speed without speed fluctuation |
percent of speed
change necessary for corrective action by the fuel control |
ability to maintain
constant speed regardless of engine load |
|
D |
The principal
characteristic of an isochronous governor is it will __________. |
slow the machine
down as the load is increased |
shut down the
engine if it over speeds |
display excessive
speed droop |
maintain a constant
speed with variations of load |
|
B |
Diesel engine
control can be obtained by the bridge __________. |
at any time |
only after the
engine room control station is switched to 'bridge control' |
whenever the secondary
station is switched to 'bridge control' |
with the approval
of the chief engineer only |
|
B |
Direct reversible
main propulsion diesel engines would normally be fitted with a/an __________. |
constant speed
governor |
variable speed
governor |
isochronous hunting
governor |
nutating disk
governor |
|
B |
The direct acting
mechanical governor used with some small diesel engines, controls fuel flow
to the engine by __________. |
governor flyweight
action on a pilot valve which controls fuel injection |
governor flyweight
motion acting on fuel controls through suitable linkage |
positioning a
butterfly valve in the fuel delivery system |
positioning a
servomotor piston attached to the fuel controls |
|
C |
The function of
the synchronizing motor on the generator governor illustrated is to __________.
Illustration MO-0092 |
drive the terminal
shaft at a set speed |
turn the governor
drive shaft during start-up |
provide remote
control for speed adjustment |
power the generator
synchronizing lamps |
|
B |
The governor,
shown in the illustration, will have its preset speed droop altered whenever
__________. Illustration MO-0092 |
the speeder spring
tension is changed |
the speed droop
lever fulcrum is changed |
the compensating
lever fulcrum is changed |
All of the above. |
|
A |
As the load is
being decreased on the engine controlled by the governor shown in the illustration,
the __________. Illustration MO-0092 |
right hand end
of the floating lever will move up |
speeder rod will
move down |
pilot valve plunger
will move down |
oil pressure under
the power piston will increase |
|
C |
In a simple hydraulic
governor with speed droop, oil under pressure is maintained ready for use
in the __________. |
power piston |
governor sump |
spring-loaded
piston accumulator |
pressure pilot
valve assembly |
|
C |
The purpose of
the compensating adjustment used in a diesel engine hydraulic governor is
to __________. |
compensate for
low oil level |
increase governor
promptness |
prevent governor
hunting |
limit engine load |
|
B |
Which of the following
statements is correct concerning the operating function of the governor
shown in the illustration? Illustration MO-0096 |
The dial type
adjusting knob (B) is used for setting speed droop and damping out hunting. |
Excess oil under
high pressure is released from the spring loaded accumulators to the sump. |
The speed droop
lever spring prevents the engine from racing or hunting by arresting the
movement of the power piston after a speed change. |
The compensating
mechanism provides positive control to lower engine speed as load is increased. |
|
C |
If governor Item
#19 in the illustration were to break on a diesel engine operating under
full load, the engine RPM will __________. Illustration MO-0095 |
increase until
the over speed trip actuated |
hunt until stabilized
by droop rod |
decrease to a
slightly lower value |
remain the same
until manually changed |
|
B |
In the illustrated
auxiliary diesel engine governor, decreasing the distance between piece
#6 and piece #10 will affect the engine by __________. Illustration MO-0094 |
decreasing the
speed |
increasing the
speed |
increasing the
speed droop setting |
decreasing the
over speed trip setting |
|
B |
The reversing
cams of some four-stroke/cycle diesel engines are brought into position
by __________. |
moving the idler
sprockets in the drive chain |
sliding the camshaft
along its axis |
rotating the cam
followers 180° |
rotating the cam
180° |
|
D |
What is the primary
purpose of the pneumatic component shown in the illustration? Illustration
MO-0119 |
If the locking
handle is in any position other than 'zero', the output of the pneumatic
valve will equal the input. |
The indicated
valve prevents transmission of transient signals to the governor speeder
spring. |
The valve with
finite positioning is used to segregate terminal signals originated by the
governor whenever the throttle is repositioned. |
If the throttle
is manually moved from its 'zero' position, the resulting effect will tend
to override the output of the governor, and secure the air to the control
circuit. |
|
C |
The pneumatic
circuit shown in the illustration is part of a complex large low speed engine
control system. Which of the following statements describes the function
of this circuit? Illustration MO-0117 |
The circuit shown
is used to shift the cam shaft position when reversing the engine. |
The piston labeled
A provides a low pressure signal to the other components illustrated. |
Valve D, when
depressed, allows the retained pneumatic pressure within the shut-down servo
motor to be relieved. |
When oil pressure
to valve C is diminished, a pressure decrease is developed at valve D, causing
it to shift, and nullifying the actuating signal to device A. |
|
A |
If the input signal
rises above the set point of '17A', shown in the illustration, but remains
below the set point of '17B', the output from '22A' will __________. Illustration
MO-0114 |
indicate a pressure
on '67B' equal to the set point of '17A' |
be the same as
the set point of '17B' |
indicate a pressure
on '67A' equal to the input of '17A' |
improve to a steady
state when moisture is removed from the system |
|
B |
The circuit shown
in the illustration represents a/an __________. Illustration MO-0115 |
infinitely positioned
pneumatic control |
detented, control
air pressure, reducing and filtering unit |
pneumatic actuated,
multiple position, control unit |
hydraulic actuated,
multi-position control unit |
|
B |
Which of the operating
positions, for valve "A" shown in the illustration, should be
chosen to maintain the circuit in continuous flow, regardless of failure
to the included downstream components? Illustration MO-0115 |
1 |
2 |
3 |
4 |
|
B |
Which of the following
statements describes the function of the device labeled "C" shown
in the illustration? Illustration MO-0115 |
The device is
a relief valve with feedback to prevent excessive pressure from damaging
system components. |
The regulator,
or pressure reducer, drops the supply pressure to the desired operating
level. |
The regulator
reduces the pressure of the supply air to provide ancillary main engine
services. |
Constant pressure
is maintained at device "B" while device "C" is used
only to modify the output signal. |
|
C |
Which of the following
statements describes the primary reason for the device shown in the illustration
to be incorporated into the air start system? Illustration MO-0116 |
This unit controls
the air operated turning motor exhaust when the unit is in operation. |
The three position
valve prevents the fuel flow reaching the fuel injection pumps. |
The unit shown
is used to prevent starting of the main engine when the turning gear is
engaged. |
The shuttle valve
compensates for any decrease in the operator's physical abilities. |
|
B |
A propulsion engine,
using the speed control circuit shown in the illustration, fails to function
at speeds lower than the low end of the critical speed range. Which of the
following statements describes what should be done to correct this malfunction?
Illustration MO-0114 |
To increase the
critical speed range of the engine, reduce the setpoint of 17A and 17B respectively,
to 0.80 bar and 1.0 bar. |
Device 17A needs
to be replaced, repaired, or reset to the setpoint coinciding with the RPM
value for the low end of the critical speed range. |
The critical speed
range will be varied as the setpoints of 17A or 17B are reset, therefore,
another segment of the speed control circuit must be repaired. |
Both 17A and 17B
need to be reset to decrease the critical speed range, although this procedure
will increase the operating range of the engine. |
|
C |
A diesel engine
operates erratically, over speeds, and fails to restart when cranked at
normal speed. Which of the following problems is the most likely cause for
the engine failing to restart? |
Failure to reposition
the fuel rack |
Improper governor
operation due to excess oil pressure |
Failure to reset
the over speed trip |
Damage to the
governor due to excessive speed |
|
B |
A propulsion engine,
using the speed control circuit shown in the illustration, fails to function
at speeds lower than the low end of the critical speed range. Which of the
following statements describes what should be done to correct this malfunction?
Illustration MO-0114 |
To increase the
critical speed range of the engine, reduce the set point of 17A and 17B
respectively, to .80 bar and 1.0 bar. |
Device 17A needs
to be replaced, repaired, or reset to the set point coinciding with the
RPM value for the low end of the critical speed range. |
The critical speed
range will be varied as the set points of 17A or 17B are reset, therefore,
another segment of the speed control circuit must be repaired. |
Both 17A and 17B
need to be reset to decrease the critical speed range, although this procedure
will increase the operating range of the engine. |
|
B |
The governor utilized
with the device shown in the illustration has become inoperative while the
vessel is underway at sea. Which of the following statements describes what
action should be taken? Illustration MO-0119 |
The linkage to
the shut down servomotor and the governor output shaft must be disconnected
in order to operate the engine via the fuel control lever. |
The engine speed
can be controlled using the fuel control lever without changing the position
of the maximum fuel stop. |
It is necessary
to disconnect the shuttle valve from the throttle lever horizontal bar,
in order to effectively jump out the pneumatic engine enable control circuit. |
The governor should
be replaced with one that has been proven to be useful in isochronous applications. |
|
D |
Direct reversible
main propulsion diesel engines would normally be fitted with a/an __________. |
isochronous hunting
governor |
constant speed
governor |
nutating disk
governor |
variable speed
governor |
|
C |
The direct acting
mechanical governor used with some small diesel engines, controls fuel flow
to the engine by __________. |
positioning a
servomotor piston attached to the fuel controls |
governor flyweight
action on a pilot valve which controls fuel injection |
governor flyweight
motion acting on fuel controls through suitable linkage |
positioning a
butterfly valve in the fuel delivery system |
|
B |
The governor for
an emergency diesel generator is shown in the illustration. When a large
change in load results in a change in engine speed, which of the parts listed
will be the FIRST governor component to react to the change in load? Illustration
MO-0094 |
Piece #8 |
Piece #9 |
Piece #13 |
Piece #21 |
|
A |
Increasing the
oil pressure acting on the power piston of the hydraulic governor shown
in the illustration will __________. Illustration MO-0092 |
increase the governor
output power |
decrease the speed
droop |
require the over
speed trip setting to be adjusted |
increase the speed
droop |
|
D |
The purpose of
the compensating adjustment used in a diesel engine hydraulic governor is
to __________. |
compensate for
low oil level |
increase governor
promptness |
limit engine load |
prevent governor
hunting |
|
C |
A schematic diagram
of an isochronous hydraulic governor is shown in the illustration. When
the load is removed the speed increases, and the____________. Illustration
MO-0100 |
balance piston
(piece 22) moves downward |
flyweights (piece
8 and 9) move inward and the pilot valve (piece 10) moves downward |
pilot valve (piece
10) moves upward |
proportioner piston
(piece 25) moves upward |
|
A |
Which of the following
statements is correct concerning the operating function of the governor
shown in the illustration? Illustration MO-0096 |
Excess oil under
high pressure is released from the spring loaded accumulators to the sump. |
The speed droop
lever spring prevents the engine from racing or hunting by arresting the
movement of the power piston after a speed change. |
The dial type
adjusting knob (B) is used for setting speed droop and damping out hunting. |
The compensating
mechanism provides positive control to lower engine speed as load is increased. |
|
C |
A diesel generator
governor is hunting. After changing the oil, the governor is flushed and
the compensation needle valve is adjusted, but the hunting persists. You
should NOW __________. |
set the speed
droop adjustment to zero |
calibrate the
fuel pump rack settings |
carefully check
for binding in the governor linkage |
check air intake
manifold pressure |
|
D |
The most common
contaminate of governor hydraulic fluid is __________. |
air |
acid |
moisture |
dirt |
|
A |
If the compensating
needle valve of a hydraulic governor is opened more than necessary the governor
will __________. |
produce excessive
speed response to a load change |
stabilize engine
speed at the new governor setting |
have a larger
than normal dead band |
respond slowly
to any change in engine load |
|
B |
A large change
in ambient temperature, or using an oil of a viscosity different than the
one recommended by the manufacturer in a mechanical hydraulic governor,
will result in the need to adjust the __________. |
accumulator spring
tension |
compensating needle
valve |
pilot valve opening |
compensating spring
tension |
|
C |
Adjustments to
the compensating needle valve in a hydraulic governor should be made with
the engine at __________. |
half speed and
normal temperature |
maximum power
at a normal load |
normal operating
temperature without a load |
maximum power
and load under normal conditions |
|
C |
If the speeder
spring of a main propulsion diesel engine governor breaks while operating
at full load, the engine RPM will __________. |
hunt until stabilized
by the droop rod |
increase until
the over speed trip actuated |
decrease to a
slightly lower value |
remain the same
until manually changed |
|
A |
The hunting of
a diesel engine may be caused by __________. |
low governor power |
excessive speed
droop |
excessive sensitivity |
insufficient speed
droop |
|
A |
Governor hunting
is caused by __________. |
governor over-control |
excessive speed
droop |
insufficient speed
droop |
governor under-control |
|
A |
If the operating
speed of a diesel engine increases without an apparent change in the engine
control settings, you may suspect a __________. |
malfunctioning
governor |
leaking air starting
valve |
control air leak |
clogged intake
air intercooler |
|
D |
Cooling the intake
air supplied to a diesel engine will __________. |
reduce mean effective
pressure |
decrease average
compression ratio |
decrease air charge
density |
increase peak
power output |
|
C |
A large, low-speed,
main propulsion diesel engine uses sea water to directly cool the __________. |
cylinder heads |
exhaust valves |
scavenging air |
injectors |
|
C |
An increase in
the air inlet manifold pressure of a diesel engine will result in a/an __________. |
decrease in maximum
cylinder pressure |
increase in ignition
lag |
decrease in fuel
consumption per horsepower-hour |
decrease in exhaust
manifold pressure |
|
B |
In a naturally
aspirated diesel engine, the volume of air intake is directly associated
with engine __________. |
compression ratio |
displacement |
fuel pressure |
cylinder clearance
volume |
|
D |
What is the function
of the after coolers installed in the diesel engine air intake system? |
Decrease the air
density |
Increase the exhaust
temperature |
Decrease the lube
oil temperature |
Increase the air
density |
|
C |
The section of
the turbocharger which would be connected to the aftercooler inlet is labeled
__________. Illustration MO-0080 |
C |
H |
B |
K |
|
A |
Item labeled "L"
as shown in section 6 of the illustration is identified as the __________.
Illustration MO-0025 |
after cooler |
non return scavenge
valve |
air filter |
exhaust manifold |
|
B |
Which of the air
intake systems listed will result in the lowest specific fuel consumption? |
Natural aspiration |
Turbocharged |
Roots blower |
Piston blower |
|
A |
Compared to a
naturally aspirated diesel engine, a supercharged diesel engine has __________. |
a cylinder air
charge of higher pressure |
reduced cylinder
mean effective pressure |
less valve overlap |
reduced blow-by |
|
A |
A naturally aspirated
diesel engine at full throttle will have an intake manifold pressure __________. |
slightly less
than atmospheric pressure |
approximately
equal to exhaust manifold pressure at all times |
that is widely
fluctuating |
constantly decreasing
as engine load increases |
|
B |
In accordance
with Coast Guard Regulations (46 CFR Part 112), which of the listed starting
aids is acceptable for use with the emergency diesel generator? |
Injection of ether
into the air intake. |
Thermostatically
controlled electric water jacket heater. |
Thermostatically
controlled electric oil sump heater. |
Heating the starting
battery. |
|
D |
What device is
installed and used as a safety feature to satisfy Coast Guard regulations
for the unit shown in the illustration? Illustration MO-0116 |
Spring clutch |
Overrunning clutch |
Pneumatic three
position valve |
Electrical limit
switch |
|
A |
Coast Guard Regulations
(46 CFR Part 56) require steel tubing connections and fittings used with
diesel fuel oil systems, to be either flared or __________. |
of the flareless
nonbite type |
silver soldered |
have welded flanges |
have seal-welded
threads |
|
A |
In accordance
with 46 CFR Part 46, diesel fuel oil system valves for removing water or
impurities are __________.
"Watch out for this one. I believe it should be Part 56 not 46." |
permitted, provided
they are fitted with caps or plugs |
required, if there
are no separators installed on board |
not required,
provided there is a high and low tank suction |
strictly prohibited |
|
D |
Before any work
is done on a burner in an automatically fired auxiliary boiler, you should
always __________. |
block all control
valves |
allow the boiler
to cool completely |
lock all safety
interlock switches closed |
close all manually
operated fuel valves |
|
C |
Before any work
is to be carried out on a burner in an automatically fired auxiliary boiler,
you should always __________. |
block all control
system relays closed |
allow the boiler
to cool completely |
close all manually
operated fuel valves |
lock all safety
interlock switches closed |
|
B |
The starter control
valve in the hydraulic system shown in the illustration is malfunctioning.
Before removing the valve, you must first __________. Illustration MO-0049 |
drain the reservoir |
bleed off all
accumulator pressure in "E" |
remove all plugs
from the system |
ensure that the
accumulator piston is in the charged position |
|
A |
Which of the listed
items should be secured before performing any maintenance on a solenoid
operated air start valve? |
Electric power
and starting air |
Lube oil standby
pump and control air |
Hydraulic switch
and engage jacking gear |
Motor drain and
pneumatic control system power |
|
A |
If a diesel engine
has been stopped because of piston seizure due to severe overheating, the
crankcase __________. |
inspection covers
should not be opened until the engine has cooled |
ventilation system
should be continued in operation for one hour for cooling |
scavenge pump
should be immediately secured to prevent loss of lube oil |
explosion covers
should be opened slightly to provide extra ventilation |
|
A |
When cleaning
a duplex strainer, it is important for __________. |
the pressure to
be bled prior to opening the compartment cover |
the lube oil to
be allowed to cool before removing the basket |
the cleaning fluid
viscosity to be more viscous than the lube oil |
a new cover gasket
to be installed when reassembling the unit |
|
D |
When a nozzle
tester is used to check the spray pattern of a diesel fuel injection nozzle,
which of the following statements is true? |
The valve should
normally begin to open at 1/2 the popping pressure |
The needle valve
spring should always be removed first before testing |
The needle valve
should remain open after the nozzle pops open |
A serious hazard
of blood poisoning exists if the fuel spray penetrates the skin of the operator |
|
D |
The principal
hazard to personnel when using a diesel engine fuel nozzle tester is __________. |
electrical shock |
toxic fumes |
explosion |
blood poisoning |
|
B |
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 __________. |
high cost of fuel |
serious fire hazard |
pollution hazard |
poor combustion
which will occur in that cylinder |
|
D |
Which of the following
precautions should be taken when cleaning the air filter on a diesel engine
equipped with a turbocharger? |
Reduce engine
speed to idle before removing the filter. |
Soak the dirty
filter in kerosene only. |
Blow out the air
inlet with compressed air. |
With the engine
stopped, cover the air inlet after removing the filter. |
|
D |
Following the
failure of one turbocharger on a large, crosshead, main propulsion diesel
engine, fitted with multiple turbochargers, which of the following actions
should be taken prior to further operation of the engine? |
Blank off the
exhaust gas inlet to the damaged turbocharger. |
Secure cooling
and lubrication to the damaged turbocharger. |
Lock the rotor
of the damaged turbocharger. |
All of the above. |
|
A |
The gage glass
on a coil-type auxiliary boiler is connected to the __________. |
accumulator |
surge chamber |
heating coil inlet
and outlet |
water softener |
|
B |
Downcomers installed
on auxiliary package boilers are protected from direct contact with hot
gases by __________. |
steel baffles |
refractory and
insulation |
water wall tubes |
several rows of
screen tubes |
|
C |
Which of the following
statements concerning fire-tube boilers is correct? |
Flames impinge
on the tubes. |
Water flows through
the tubes. |
Combustion gases
flow through the tubes. |
Combustion occurs
in the tubes. |
|
A |
The boiler shown
in the illustration would be classed as __________. Illustration MO-0064 |
single-pass, fire-tube,
scotch marine |
forced circulation,
coil-type |
two-pass, scotch
marine |
two-pass, water-tube |
|
A |
Which of the listed
problems will happen when the water level of a fire-tube type auxiliary
boiler approaches the crown sheet? |
The fusible plugs
will melt. |
The furnace will
explode. |
The furnace will
overheat. |
Excess steam will
be generated. |
|
A |
When preparing
to light off a cold boiler equipped with a return flow fuel oil system,
the recirculating valve directs the flow of oil __________. |
back to the suction
side of the service pump |
directly to the
fuel oil heater inlet for further warm-up |
directly to the
deep tanks |
back to the fuel
oil settler for further filtration |
|
A |
Why should the
main steam stop valve of an auxiliary boiler be eased off its seat and then
gently closed before lighting off? |
To ensure that
the valve will not be seized shut when hot. |
To check the valve
packing. |
To check for a
tight bonnet seal. |
To examine the
valve stem for scars or nicks. |
|
B |
Which of the automatic
boiler controls listed should be tested prior to lighting off an auxiliary
boiler? |
Voltage output
of the ignition transformer |
Low water level
cutoff switch |
Automatic bottom
blow valve |
Insulation resistance
readings in the ignition system high tension leads |
|
B |
As shown in the
illustration, the function of component "1" is to __________.
Illustration MO-0128 |
generate superheated
steam to operate the turbo generator |
evaporate circulating
boiler water into saturated steam |
condense excess
steam produced in the boiler |
maintain a water
level in the steam drum |
|
B |
As shown in the
illustration, what component would normally be installed at location "D"?
Illustration MO-0128 |
Boiler soot blower
unit |
Oil fired mechanical
burner |
Boiler water level
indicator |
Flue gas smoke
indicator |
|
A |
As shown in the
illustration, the component labeled 'E' would be identified as a __________.
Illustration MO-0128 |
waste heat boiler
circulating pump |
boiler water feed
pump |
main condensate
pump |
fuel oil service
pump |
|
C |
As shown in the
illustration, the component labeled "H" would be identified as
a __________. Illustration MO-0128 |
waste heat boiler
circulating pump |
fuel oil service
pump |
main condensate
pump |
boiler water feed
pump |
|
B |
In general, diesel
engine waste heat boiler construction is usually of the __________. |
dry back boiler
type |
water-tube type |
critical circulation
boiler type |
cyclone furnace
boiler type |
|
B |
The purpose of
designing some waste heat boilers with sinuous fire tubes, is to __________. |
reduce accumulations
of carbon deposits on the heat transfer surfaces |
increase the rate
of heat transfer to the waterside |
increase exhaust
gas velocity through the boiler |
eliminate exhaust
gas pulsations and noise |
|
B |
An exhaust gas
bypass is installed on a waste heat boiler in order to __________. |
bypass a portion
of the exhaust gas at peak loads for better efficiency |
minimize moisture
condensation in the boiler gas passages at low loads |
bypass exhaust
gas at high loads to prevent excessive back pressure |
recycle exhaust
gas to the turbocharger |
|
D |
Which of the following
is necessary for all waste heat boiler installations, regardless of design
or manufacturer? |
Installation of
a superheater |
An independent
means to prevent feed water contamination |
Installation of
a powered circulating booster pump |
A means to control
of evaporation |
|
A |
With which of
the following types of diesel engine arrangements is a waste heat boiler
most likely to produce the maximum steam pressure, temperature, and flow
conditions? |
Supercharged,
four-stroke/cycle diesel engine |
Supercharged,
loop scavenged diesel engine |
Turbocharged,
cross flow scavenged diesel engine |
Turbocharged,
return flow diesel engine |
|
A |
Waste heat boilers
may be equipped with vents on the feedwater heater heads to __________. |
prevent air binding |
release excess
pressure |
allow for feedwater
treatment |
remove sediment |
|
D |
Casing drains
may be required on a waste heat boiler gas passage side to __________. |
prevent an accumulation
of boiler water entering gas passages as a result of a pinhole tube leak |
as a means to
sample stack gases for testing |
release excess
pressure |
drain off condensation |
|
D |
Constant capacity,
pressure atomizing, fuel burners designed to meet a wide variation in steaming
loads on an auxiliary boiler, are __________. |
automatically
supplied with warmer air on demand |
automatically
supplied with more fuel on demand |
equipped with
standard variable capacity atomizers |
cycled on and
off in response to steam demand |
|
C |
The primary function
of a flame safeguard system, as used on an automatically fired auxiliary
boiler, is to prevent __________. |
accidental dry
firing and overpressure |
uncontrolled fires
in the furnace |
explosions in
the boiler furnace |
overheating of
the pressure parts |
|
A |
A photoelectric
cell installed in an automatically fired auxiliary boiler burner management
system __________. |
opens the burner
circuit upon sensing a flame failure |
detects a flame
failure by monitoring radiant heat from glowing refractory |
requires mechanical
linkage to secure the burner fuel supply |
must be bypassed
at low firing rates |
|
A |
During unsafe
firing conditions in a large automatic auxiliary boiler, various control
actuators are interlocked with the burner circuit to prevent start-up, in
addition to safety shutdown. These controls are referred to as __________. |
limit controls |
flame safeguard
controls |
combustion controls |
programming controls |
|
D |
The pressuretrol
which is installed on an auxiliary boiler senses steam pressure changes
and __________. |
controls the flow
of feed water to the boiler |
monitors the boiler
high water level |
secures the fires
when a fusible plug burns out |
automatically
regulates the quantity of oil and air flow to the burner |
|
C |
Which of the following
statements describes how the fuel oil enters the whirling chambers of the
sprayer plates used in a auxiliary boiler return flow fuel oil system? |
Through the outer
barrel tube. |
Through the sprayer
plate drilled passages. |
Through tangential
slots in the sprayer plate. |
Through baffles
in the orifice plate. |
|
C |
The solenoid valves
in the fuel oil supply line to an automatically fired auxiliary boiler,
are automatically closed by __________. |
a decrease in
feed temperature |
high furnace air
pressure |
high steam pressure |
low steam pressure |
|
B |
A variable capacity,
pressure atomizing, fuel oil burner functions to __________. |
maintain a constant
fuel temperature |
provide a wide
range of combustion |
provide a constant
fuel return pressure |
maintain smokeless
fuel oil atomization |
|
A |
When the steam
pressure drops below a set value on an automatically fired auxiliary boiler,
fitted with rotary cup atomizers, the combustion control system will __________. |
increase the fuel
oil control valve opening |
increase the rotary
cup speed |
decrease the back
pressure regulating valve opening |
decrease the supply
steam control valve opening |
|
B |
Control of the
fuel oil metering valve in an automatically fired auxiliary boiler is accomplished
by a __________. |
pressure magnifying
device in the steam coil outlet |
steam pressure
sensing device with linkage to the damper air vanes |
metering device
in the air supply line |
signal from the
feed water electrode |
|
B |
In the water level
electrode assembly, shown in the illustration, the feed pump should restart
when the level of the water reaches the position indicated by arrow __________.
Illustration MO-0047 |
B |
C |
E |
D |
|
A |
Which of the following
types of feedwater regulators is commonly used with a water-tube, natural
circulation, auxiliary boiler? |
Thermo mechanical |
Bimetallic element |
Ring thermostat |
Modulating pressuretrol |
|
D |
Heavy soot accumulations
in an auxiliary boiler could be caused by __________. |
water in the fuel
oil |
excessive cycling |
high fuel oil
pressure |
improper burner
maintenance |
|
A |
Burner ignition
failure in an automatically fired auxiliary boiler would be caused by __________. |
a burned out solenoid
in the oil supply valve |
high temperature
excess air |
incorrectly setting
the hot well dump valve |
an incorrectly
positioned burner snubber relay |
|
C |
In the event of
a flame failure in an auxiliary water-tube boiler, you must __________. |
relight the boiler
immediately to prevent loss of steam pressure |
relight the fire
off the brickwork as long as the bricks are cherry red |
purge the furnace
of any combustible gases before attempting to relight the fire |
speed up the feed
pump to prevent dry firing when the burner flame is reestablished |
|
D |
A burner producing
black smoke in an automatic auxiliary boiler, would be caused by a/an __________. |
incorrect electrode
setting |
defective solenoid
valve |
grounded high
tension lead |
incorrect primary
air setting |
|
B |
A feed pump for
an auxiliary boiler might lose suction if the __________. |
boiler water level
is low |
feed water is
too hot |
boiler steam demand
is low |
feed water is
too cold |
|
D |
A safety valve
on an auxiliary boiler simmers constantly and cannot be stopped by several
quick blow-offs using the hand relieving gear. The problem may be __________. |
loose dirt on
the seat |
exposed valve
springs |
a clogged drain
line |
a damaged seat |
|
B |
Which of the following
devices will increase the power output of a diesel engine without increasing
its frictional load? |
Gear-driven centrifugal
blower |
Turbine-driven
centrifugal blower |
Roots-type rotary
blower |
Positive displacement
blower |
|
C |
A loop or cross
scavenged engine utilizes the motion of its pistons and a turbocharger to
provide scavenging air. Which of the listed mechanical designs prevents
the air under the pistons from being pumped back through the scavenge ports
during the piston power stroke? |
Positive pressure
from the blower |
Masked intake
ports |
Length of the
piston skirt |
Lower liner seals |
|
D |
Clearance volume
scavenging in a turbocharged, four-stroke/cycle diesel engine is accomplished
__________. |
with only the
exhaust valve open |
without cooling
the cylinders or pistons |
at a pressure
below atmospheric |
during the valve
overlap period |
|
D |
In a turbocharger,
inlet air velocity is increased in the __________. |
compressor outlet
volute |
stationary diffuser
passages |
inlet nozzle ring |
rotating impeller
vanes |
|
B |
Which of the following
statements is correct regarding a turbocharged four-stroke cycle diesel-
generator? |
At full load the
intake manifold pressure and exhaust manifold pressure are equal. |
At full load the
intake manifold pressure is greater than the exhaust manifold pressure. |
At zero load the
intake manifold pressure is greater than the exhaust manifold pressure. |
At full load the
intake manifold pressure is less than the exhaust manifold pressure. |
|
A |
Large, two-stroke/cycle,
main propulsion, diesel engine cylinders can be successfully pressure charged
during normal operation, by using the __________. |
constant or pulse
pressure system |
constant volume
system |
exhaust load system |
exhaust gas temperature
system |
|
A |
In a two cycle
diesel engine, a Roots type blower is usually __________. |
gear driven by
the engine |
driven by separate
motor |
actuated by the
intake valves |
driven by an exhaust
gas turbine |
|
D |
The diesel engine
shown in the illustration, is provided with an auxiliary blower to __________.
Illustration MO-0003 |
maintain a positive
pressure on the crankcase |
increase scavenge
air pressure at full load |
maintain a vacuum
on the crankcase |
provide scavenge
air pressure at low load |
|
C |
Maintaining the
lowest possible scavenging air temperature at all times is not recommended
due to the possibility of the __________. |
compression pressure
being greatly reduced |
air charge density
becoming too high |
formation of excessive
quantities of condensate |
piston crown surfaces
becoming too cold |
|
D |
Which of the following
precautions should be taken when cleaning the air filter on a diesel engine
equipped with a turbocharger? |
Reduce engine
speed to idle before removing the filter. |
Soak the dirty
filter in kerosene only. |
Blow out the air
inlet with compressed air. |
With the engine
stopped, cover the air inlet after removing the filter. |
|
D |
Following the
failure of one turbocharger on a large, crosshead, main propulsion diesel
engine, fitted with multiple turbochargers, which of the following actions
should be taken prior to further operation of the engine? |
Blank off the
exhaust gas inlet to the damaged turbocharger. |
Secure cooling
and lubrication to the damaged turbocharger. |
Lock the rotor
of the damaged turbocharger. |
All of the above. |
|
C |
When checking
for the presence of sulfite in the feed water of an auxiliary boiler, you
are in essence checking __________. |
the hardness of
the makeup feed water |
to ensure the
compound additions are adequate for control of pH |
to ensure the
compound additions are adequate for controlling dissolved oxygen |
to ensure the
automatic or manual blow down rate and frequency is adequate for control
of total dissolved solids |
|
D |
Before any work
is done on a burner in an automatically fired auxiliary boiler, you should
always __________. |
block all control
valves |
allow the boiler
to cool completely |
lock all safety
interlock switches closed |
close all manually
operated fuel valves |
|
C |
Before any work
is to be carried out on a burner in an automatically fired auxiliary boiler,
you should always __________. |
block all control
system relays closed |
allow the boiler
to cool completely |
close all manually
operated fuel valves |
lock all safety
interlock switches closed |
