WorksheetsMotores 5-8
Total questions: 60
Worksheet time: 30mins
The expansion tank in a diesel engine closed freshwater cooling system is located at __________.
the highest point in the system
the lowest point in the system
or near the floor plate level
or near the tank top level
In the slow speed diesel engine shown in the illustration, the part labeled "E" is the __________.
high pressure lube oil line
low pressure lube oil line
high pressure fuel line
low pressure fuel line
Where is a fusible plug installed on a Scotch or auxiliary boiler?
At the shell approximately 1 1/2 inches (3.8 cm) below the normal waterline.
At or near the center of the crown sheet of the combustion chamber.
In the furnace approximately 1 1/2 inches (3.8 cm) below the normal waterline.
In the furnace not more than 1 inch (2.54 cm) below the lowest permissible water level.
The quantity of air delivered at any given speed by a Roots-type blower, as shown in the illustration, decreases as the pressure ratio increases. This is due to the __________.
decrease in clearance between the mating lobes
increase in air leakage past the rotors
decrease in air leakage past the rotors
increase in clearance between the mating lobes
If the speed of the propeller is 135 RPM, the speed of the engine camshaft shown in the illustration will be __________.
135 RPM
270 RPM
variable depending on the camshaft gear train gear ratios
variable depending on the ratio between engine rpm and propeller shaft rpm
As a general rule, the recommended operating water jacket outlet temperature range for medium and high speed marine diesels with closed cooling systems is __________.
120° to 139°F
140° to 169°F
170° to 189°F
190° to 219°F
The water inlet manifold for the diesel engine shown in the illustration is represented by the letter or number __________.
"M"
"N"
"W"
"13"
In reducing engine speed to an efficient propeller speed by the use of reduction gears, __________.
speed and torque are both reduced
speed is reduced and torque remains unchanged
speed is reduced and torque is increased
speed is sometimes unchanged while torque is increased
Which of the operating characteristics listed applies to the Roots-type blower shown in the illustration?
Each set of lobes is independently driven, assuring proper timing.
Compression of the air is accomplished between the rotors.
Air delivery is approximately proportional to engine speed.
All of the above
Why do most temperature control valves in diesel engine closed freshwater cooling systems vary the flow of jacket water through the cooler instead of through the engine?
Changing the rate of flow in the jackets could cause localized hot spots.
Emergency hand control would not be possible if water flow through the jackets were controlled.
Excessive cooling would take place in the heat exchangers at high loads.
Excessive cavitation erosion would take place in the coolers.
Which of the components listed is used to control the diesel engine speed shown in the illustration?
"C"
"D"
"E"
"G"
One function of the fuel pump delivery check valve is to __________.
prevent carbon deposits from forming on the injector nozzle
help the injector needle reseat without dribbling at the nozzle holes
maintain popping pressure in the high pressure steel piping to the injector
ensure a fuel leak off between the plunger and barrel which provides lubrication for relative movement
Flame failure in an automatically fired auxiliary boiler can result from a/an 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?
incorrect electrode setting
incorrect nozzle position
clogged fuel nozzle
broken high tension lead
Friction developing between the moving parts of a governor, governor linkage and control valve will cause the governor to __________.
react with insufficient speed droop
fail to react to small speed changes
have excessive sensitivity to small speed changes
remain in the neutral position
A diesel engine is equipped with an isochronous hydraulic governor. A decrease in load will cause the engine speed to __________.
decrease only
increase only
decrease slightly then returned to original speed
increase slightly then returned to original speed
On an automatically fired auxiliary boiler, the steam pressure limit switch is wired into the burner electric circuit to __________.
sound an alarm when the burner is shut off
energized the flame scanner circuit when high boiler pressure is reached
shut off the burner when the cutoff pressure is reached
prevent burner operation in the event of low boiler water level
prevent burner operation in the event of low boiler water level
I only
II only
both I and II
neither I nor II
In addition to the normal governor, each main engine having a maximum continuous output of 300 hp and over, which can be declutched or which drives a controllable pitch propeller, __________.
is not required to have any additional overspeed protection provided a hydraulic governor is used
and is a direct reversible engine, is required to have an overspeed trip set to secure the fuel to the engine when its rated speed is exceeded by more than 15 percent
is to be fitted with a separate overspeed device so adjusted that the speed cannot exceed the maximum rated speed by more than 20 percent
will not require any additional overspeed protection provided a mechanical type governor is used
Ignition failure in an auxiliary boiler can be caused by __________.
carbon deposits on electrodes
a jammed open oil solenoid
excess fuel pressure at the nozzle
an excessively long purge cycle
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
In order for the self-cleaning fuel oil centrifuge, shown in the illustration, to properly operate during the desludge cycles, the __________.
bowl locking ring alignment mark should be approximately 1/4 inch to the left of the bowl alignment mark
sliding bowl bottom and operating slide seal rings should be coated with main engine lube oil
sliding bowl bottom and operating slide seal rings should be coated with a high temperature lubricating paste
all of the above
Loss of lubricating oil pressure to the main propulsion diesel engine will actuate a/an __________.
overspeed trip
audible/visual alarm
the ships/boats general alarm
reserve oil storage tank
When two direct air start reversible medium speed diesel engines are coupled in parallel to a common propeller shaft, which of the operating conditions listed will apply during extended periods of maneuvering?
Full horsepower is available ahead and astern.
Mechanical reduction gearing is not required.
Full reversing torque is available.
One engine will be turning ahead and the other astern with the appropriate engine clutched in and out to answer bells.
Proper operation of the main engine reduction gear set requires the operator to monitor __________.
the sump oil level
oil flow sight glasses
bearing temperatures
all of the above
The term 'proper metering', as applied to a diesel fuel injection system, can be best defined as __________.
delivering the same quantity of fuel to each cylinder for each power stroke according to engine load
maintaining the metering adjustment for a reasonable period under all load conditions
timing fuel injection to obtain maximum power and good fuel economy
distributing the fuel to all parts of the combustion chamber for proper combustion
A 'low pressure in oil outlet' alarm indication, as shown in the illustration, may be caused by __________.
the proper setting of valve V4
insufficient heating of the processed liquid
insignificant accumulations of sludge within the bowl assembly
insignificant accumulations of sludge within the bowl assembly
Which of the following will occur when the lower edge of the spiral, on the plunger of a jerk pump, uncovers the spill port?
The plunger immediately reverses direction.
The pressure drops and fuel delivery stops.
The plunger rotates to the no fuel position.
The barrel rotates to the zero effective stroke position.
Excessive wear at part #11, shown in the illustration would result in __________.
improper timing
increased oil consumption
low oil pressure
low oil pressure
Which statement about diesel engine combustion is true?
Combustion does not begin until the piston starts down on the power stroke.
Maximum combustion pressure is reached before TDC.
Turbulence in the cylinder causes a delay in ignition.
Maximum cylinder firing pressure is not developed until the piston passes TDC.
In the pressure-volume diagram shown in the illustration, fuel injection occurs at point __________.
c
d
e
f
Which of the following statements is an accurate description of fuel injection piping used on diesel engines with a cylinder bore of 250 mm and above?
The piping shall be so arranged to allow for uncomplicated removal of the fuel injection equipment and other associated components located on the cylinder head.
All high pressure piping shall be of the double lined type, with the outer leak off line suitably channeled to a dedicated tank.
All storage tanks connected to the leak off piping of fuel injection systems shall be provided with high level alarms and sufficient means for emptying.
The piping is to be effectively shielded and secured to prevent fuel or fuel mist from reaching a source of ignition on the engine or its surroundings.
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?
Piece #8
Piece #9
Piece #13
Piece #21
A cracked cylinder head in an operating engine may be indicated by __________.
a steady flow of water from the expansion tank vent
combustion gases venting at the expansion tank
lower temperature at the cylinder head water discharge
water draining from the fuel leak off lines
Proper filtering and straining of diesel fuel is important because the __________.
fuel oil pump will overspeed if dirt is not removed
fuel oil transfer pumps cannot tolerate small amounts of grit in the oil
fuel injectors may be damaged by foreign particles in the fuel oil
dirty fuel will clog the intake air filter
The pressure-volume diagrams illustrated are of four internal combustion engine cycles. Which one represents the theoretical diesel cycle?
A
B
C
D
Which device is used to prevent over pressurization of the illustrated distiller?
"13"
"19"
"26"
"12"
From the graph shown in the illustration, determine the size of the regulating ring required for the proper operation of the fuel oil centrifuge if the fuel oil specific gravity is 0.9 kg/dm3 at 68°F, and the separating temperature is 158°F.
86 mm
104 mm
110 mm
117 mm
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 down stream components?
1
2
3
4
Excessive lube oil consumption in a diesel engine can be caused by __________.
late combustion
plugged oil wiper rings
low lube oil temperature
low lube oil pressure
What is the purpose of a hydraulic valve lash adjuster?
Compensates for the expansion and contraction of the valve stem due to changes in operating temperature.
Insures proper pressure in a hydraulic system.
Insures proper pressure in a hydraulic system.
Provides easier removal of the valve cage.
Diesel engine valve springs function to __________.
hold the valves open
keep the valves off their seats until the exhaust stroke is completed
close the valves
open inlet valves when the air injection cycle begins
The area indicated by the letter "W", shown in the illustration is correctly termed the __________.
closing chamber
parting chamber
upper sliding piston chamber
opening chamber
A six cylinder, two stroke/cycle diesel engine is 83% efficient and has a cylinder constant of 0.998 while operating with a mean effective pressure of 15 kg/cm2 at a speed of 100 RPM. What is the metric brake horse power developed?
5,559 mbhp
6,698 mbhp
7,455 mbhp
8,982 mbhp
A diesel engine indicator diagram has an area of 22 cm2 and a length of 12.5 cm. If the scale of the indicator spring is 1 mm = 1 kg/cm2, what is the cylinder mean effective pressure?
17.6 kg/cm2
27.5 kg/cm2
34.5 kg/cm2
36.0 kg/cm2
A diesel engine will lose power if fuel injection occurs too late in the cycle, because the __________.
fuel droplets will burn as they leave the fuel injector
fuel will not be properly atomized in the cylinder
maximum expansion of the burned fuel cannot take place in the cylinder
compression pressure will be too low to cause fuel ignition
Using a diesel engine indicator P-V diagram, the cylinder mean effective pressure is calculated to be 21.3 kg/cm2. What is the scale of the spring used on the indicator if the diagram area is 18.46 cm2 with a length of 13 cm?
9.0 kg/cm
10.0 kg/cm
12.5 kg/cm
15.0 kg/cm
If the speeder spring of a main propulsion diesel engine governor breaks while operating at full load, the engine RPM will __________.
increase until the overspeed trip actuated
hunt until stabilized by the droop rod
decrease to a slightly lower value
remain the same until manually changed
An operating turbocharged diesel engine that suddenly loses power, is due to a/an __________.
restricted turbocharger air intake
oil leak into the turbocharger
dribbling injector
low fuel viscositylow fuel viscosity
When a fuel injection nozzle overheats, which of the problems listed can be expected?
The fuel metering will vary.
The fuel will explode.
The cylinder head will crack.
The engine will stop.
Which of the listed set of conditions indicates early fuel injection timing?
Loss of engine power and high exhaust temperaturesLoss of engine power and high exhaust temperatures
Higher than normal firing pressure and low exhaust temperature
High fuel consumption and high exhaust temperatures
Lower than normal compression pressure and high exhaust temperature
If the separating temperature is to remain constant, what is the relationship between the specific gravity of the oil and the required size of the regulating ring?
For a constant operating temperature, the greater the specific gravity of the oil the larger the regulating ring.
The specific gravity of the oil and the size of the regulating ring are related only during the initial design stages of the centrifuge.
With oils of greater specific viscosities it is proper to select smaller regulating rings regardless of the operating temperatures desired.
The larger sized regulating rings are designed to be used with oils of lower specific gravities.
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?
3
4
5
6
If a higher than normal water level is observed through the inspection port of a low pressure distilling plant, you should suspect __________.
a leak in the feedwater heater
improper vacuum
a malfunctioning brine pump
a malfunctioning brine pump
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 __________.
expansion during the combustion process
exhaust and intake valves just closing
maximum compression pressure is just being attained
fuel injection occurring at that point and combustion begins
Which of the conditions listed could cause the cylinder relief valves on a large, low-speed, propulsion diesel engine to lift?
Plugged injector nozzles
Excessive fuel injection
Very late injection timing
Incorrect crankshaft clearances
What is the swept volume per cylinder per revolution of a six-cylinder, two-stroke/cycle diesel engine with a 580 mm bore and a 1700 mm stroke operating at 100 RPM?
0.45 cubic meters (450 L)
0.90 cubic meters (900 L)
2.7 cubic meters (2700 L)
5.4 cubic meters (5400 L)
Late fuel injection occurring at, or after TDC in a diesel engine is indicated by excessive exhaust smoke and __________.
low exhaust temperature
low firing pressure
fuel knock in each cylinder
mechanical knock in each cylinder
In an opposed piston engine, which of the following events would happen if the lower crank lead were reduced from 12° to 0°?
The exhaust ports would open before the scavenging ports.
The scavenging ports would open before the exhaust ports.
Neither the exhaust nor the scavenging ports would open.
The exhaust and scavenging ports would open simultaneously.
The device represented by the symbol "B" in the illustration is used to __________.
remove all moisture from the system
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 supplyremove most contaminants present in the air supply
Where engine bores exceed 230 mm, a bursting disc or flame arrestor is fitted __________.
at the supply inlet to the starting air manifold for non-reversing engines
on the exhaust manifold prior to the inlet of the turbocharger
on the exhaust manifold prior to the inlet of the turbocharger
in way of the control valve of each cylinder for direct reversing engines having a main starting manifold
