WorksheetsMotores 2
Total questions: 44
Worksheet time: 22mins
In comparison to exhaust valves, intake valves of diesel engines may be fabricated from low-alloy steels because __________.
the beveled edges of the intake valves provide for self-centering during seating
intake valves utilize stellite-coated valve seat inserts which reduce wear
the effective volume of air passing through intake valves is less than the effective volume of air passing through exhaust valves
intake valves are less affected by the corrosive action of exhaust gases
In a bypass type filtering system for a medium or high speed diesel engine, the lube oil bypassing the filter __________.
returns directly to the suction side of the pump
returns directly to the sump
flows to the engine bearings
flows through a second-stage strainer, reheater, and returns to the sump
Maximum lube system operating pressure for a diesel engine is normally regulated by a/an __________.
orifice in the pump suction
special filter design
pressure drop through the filter
relief valve
A diesel engine crankcase ventilation system __________.
prevents spark generation
removes combustible gases
determines the level of combustible gases
provides inert gas generation in crankcase
The lower section of a piston is called the __________.
land
skirt
crown
plate
Turbulence in a diesel engine cylinder is of major importance in providing __________.
proper fuel metering
complete fuel/air mixing
minimal fuel penetration
proper fuel timing
To determine if the lube oil filter elements need changing, __________.
open the filter and inspect the elements
check the lube oil pump discharge pressure
check the lube oil header pressure
check the pressure drop across the filter
Helical reduction gears, as used with main propulsion drive trains, are constructed so that several teeth are meshed at the same time to __________.
eliminate propeller shaft end thrust
translate heavy load into high speed output
provide smooth continuous power transmission
allow construction with fewer gear teeth
The minimum speed an engine must attain before ignition can occur depends upon __________.
the type and size of the engine
the condition of the engine
ambient temperature
all of the above
The knock occurring when a cold diesel engine is started and continues while running at low speed, but stops when the engine reaches normal operating speed and temperature, is __________.
caused by retarded injection timing
caused by a mechanical defect in one cylinder
caused by high fuel injection pressures
normal for these conditions
The RPM of "D" is 600 and hobbed with 46 teeth. If gears "A", "B", and "C" have 94, 80, and 30 teeth respectively, the RPM of "A" in the gear train illustration is __________.
84.38 RPM
110.11 RPM
510.64 RPM
71.81 RPM
The system shown in the illustration utilizes a water transducer which is __________.
similar to those used in sonar systems
located in the oil outlet piping
essential in monitoring the amount of water entering the separator
a mechanical/electrical device with a variable dc output
The heat exchanger plates, used in the device shown in the illustration, are produced from which of the listed materials?
Titanium
Anodized aluminum
Phosphor bronze
Copper
Regulator'17B' shown in the illustration, is set for a constant output of 1.2 bar and the input signal to "1" is currently 0.42 bar. If the output from '17A' can not exceed 0.85 bar, then the current output from "2" should be __________.
0.35 bar
0.42 bar
0.85 bar
2.05 bar
In a diesel engine, when refitting piston rings you should __________.
I. check the ring gap at the smallest diameter of the cylinder
II. remove carbon from the ring groove
I only
II only
both I and II
neither I nor II
Which of the indicator diagrams illustrated depicts the condition that should be corrected by the fitting of fewer or thinner shims to the connecting rod?
A
B
C
D
The PRIMARY function of a waste heat boiler is to __________.
reduce engine exhaust noise
reduce engine back pressure
recover heat which otherwise would be lost
increase turbocharger efficiency
A schematic diagram of an isochronous hydraulic governor is shown in the illustration. When the load is removed the speed increases, and the __________.
pilot valve (piece #10) moves upward
proportioner piston (piece #25) moves upward
flyweights (piece #8 and #9) move inward and the pilot valve (piece #10) moves downward
balance piston (piece #22) moves downward
During the operation of the fuel oil centrifuge shown in the illustration, liquid is passing continuously through the sludge outlet, or the bowl is unintentionally 'shooting'. The probable cause is the __________.
gravity disk inside diameter is too large
gravity disk seal ring is defective
operating slide seal ring is defective
sliding bowl bottom seal ring is defective
The minimum fuel oil delivery pressure required for efficient injection depends primarily on the __________.
degree of cylinder air turbulence
maximum pressure in the engine cylinders during injection
quantity of the fuel to be injected
duration of the injection delay period
While standing watch in the engine room, you suspect an air leak while checking a low pressure distilling plant. Which of the following should be checked as a possible cause of the air leak?
gasketed joints
valve stems
gage glass packing
all of the above
Critical speeds occurring within the operating speed range of a main propulsion diesel engine may be changed, or have their damaging effects reduced by a/an __________.
engine support vibration isolator
detuner or viscous fluid damper
lightened crankshaft flywheel
spherically seated crankshaft bearing
As shown in the illustration, the viscosimeter would be used to directly control the output of which of the following components?
Outflow from HFO day tank.
Final heaters.
Injector pumps.
HFO purifiers.
Which of the following conditions will cause the engine to operate in area "A" of the diagram shown in the illustration?
Fouled hull
Inclement weather
Damaged propeller blades
Vessel operating with minimum loading
In a bypass type filtering system for a medium or high speed diesel engine, the lube oil passing through the filter __________.
returns directly to the suction side of the pump
returns directly to the sump
flows to the engine bearings
flows through a second-stage strainer, reheater, and returns to the pump suction
A 4 stroke, medium speed, eight cylinder, in-line diesel engine has a firing order of 1-5-2-6-8-4-7-3. When performing routine valve maintenance, #1 cylinder is set at TDC in firing position. Which exhaust valves can be checked for proper valve lash?
#1, #5, #2, #6
#1, #5, #2, #4
#1, #3, #2, #7
#1, #3, #2, #8
How many separate camshaft timing events must be controlled for the components of an air start cylinder head for a direct reversible, four stroke diesel engine?
4
6
7
8
As shown in the illustration, what component would normally be installed at location "D" ?
Boiler water level indicator
Oil fired mechanical burner
Boiler soot blower unit
Flue gas smoke indicator
As shown in the illustration, the primary function of the valve labeled "6" would be to __________.
raise vacuum during startup of the turbo generator
recirculate feedwater at low loads
relieve excess steam pressure when the turbo generator is idling
provide make-up feed water for the hot well
Which of the following conditions occurs in the section labeled "F" of the device shown in the illustration?
Non-condensable vapors are removed and water vapors are preheated.
The sea water flowing through device "I" is cooled.
The jacket water flowing through device "I" is heated.
The vapors produced in section "G" are condensed and the non-condensable gases are removed.
In a diesel engine, blow-by __________.
increases exhaust back pressure
causes excessive crankcase pressure
can only be detected by a compression check
decreases fuel consumption
A 18 cylinder medium speed direct reversible main propulsion diesel engine is being operated with one cylinder secured. When the engine was stopped, the affected cylinder stopped in a position preventing the engine from being restarted. Which of the following actions should be taken to correct the situation?
Turn the shaft with the turning gear while applying starting air.
Increase starting air pressure by small amounts until the air pressure is high enough to crank the engine over.
Admit starting air in the opposite direction to reposition the engine crankshaft and then restart in the desired direction.
Open the indicator cocks on those cylinders on compression and apply increased starting air pressure.
A sudden drop in compression pressure in one cylinder of a diesel engine can be caused by __________.
a leaking fuel injector nozzle
a clogged air filter
excessively early fuel injection
malfunctioning valves
Regarding the turbocharger shown in the illustration, the part labeled "B" would be attached to the __________.
exhaust manifold
silencer outlet
after cooler inlet
nozzle ring
In the chart shown in the illustration, a right hand rotation engine has the #9 piston on top dead center; therefore, the #1 piston is __________.
on the exhaust stroke
on the compression stroke
on the power stroke
at bottom dead center
A four-stroke/cycle six cylinder in-line diesel engine has a firing order of 1-5-3-6-2-4. When cylinder #6 is firing at top dead center, piston #4 is __________.
at top dead center
on the compression stroke
at bottom dead center
on the intake stroke
What method is used to supply air to the cylinders of the diesel engine illustrated?
Operation of the turbo charger at full load
Operation of an auxiliary blower at low load
The pumping action of the piston
All of the above are correct.
An eight cylinder, four stroke/cycle, single acting diesel engine has a 650 mm bore and a 1400 mm stroke. What will be the indicated power developed if the average mean effective pressure is 30 kg/cm2 at a speed of 100 RPM?
1689 kW
9,111 kW
12,388 kW
24,776 kW
On a large low-speed main propulsion diesel engine, lower main bearing wear is usually measured by using a/an __________.
dial indicator
outside caliper
bridge gage
tram rod
The function of diesel engine piston compression rings is to __________.
prevent piston side thrust
prevent engine friction losses
transmit heat from the piston to the cylinder liner
remove oil from the cylinder combustion space
In the common rail system, excessive pressure in the header may be caused by __________.
improper adjustment of the bypass valve
a dribble in the fuel injection nozzle
insufficient leak off through injection nozzle packing
a malfunctioning injection nozzle
A diesel engine is operating at 1800 RPM and driving a propeller at 600 RPM. What is the speed reduction ratio?
0.30 to 1
3.00 to 1
3.33 to 1
33.0 to 1
Which of the devices is commonly used in measuring the clearances between the main engine bearings and the crankshaft?
Plasti-gage
Persian blue
Copper shims
Wooden gauging pegs
The items, shown in the illustration, labeled "P" are __________.
water cooling valves
cylinder quill lubricators
air check valves
diffuser vanes
