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单选题
Operating a propulsion diesel engine at less than 30% of designed normal load for prolonged periods will result in （）.
A
decreased fuel consumption per brake horsepower
B
more complete cylinder scavenging
C
extended valve life
D
carbon formation on combustion chamber surfaces
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考题
Proper lubrication of the main bearings is more easily obtained in a single acting, four-stroke/cycle diesel engine than in a tow-stroke/cycle diesel engine because________.A.The direction of pressure on the journal in four-stroke engine is continuouslyB.positive feed lubricators are installed on all bearings of four-stroke engine, whereas as a splash feed system is used on tow-stroke engineC.four-stroke engines usually utilize a heavier grade of oil than tow-stroke enginesD.Low-stroke engines usually consume less lube oil than four-stroke engines
考题
In a main propulsion turbocharged diesel engine, the speed of the turbocharger varies according to the _____.A.governor droopB.speeder spring tensionC.fuel rack lagD.load on the engine
考题
Prolonged operation of a diesel engine with a closed cooling water system, at lower than normal designed operating temperatures can ______.A.increase power outputB.decrease lube oil viscosityC.eliminate fuel knockD.cause sulfuric acid formation
考题
The relative air pressure in the inlet manifold of a turbocharged diesel engine is usually______.A.greater than the average exhaust manifold pressureB.less than the average exhaust manifold pressureC.greater at the turbine wheel than at the impellerD.greater at reduced engine speed
考题
What is an advantage of diesel over steam turbine propulsion ________．A.Less fuel consumption per SHPB.Diesel fuel costs less than bunker C or its equivalentC.Less routine maintenance requiredD.Less weight per SHP
考题
单选题The rate of cylinder lubricating oil metered to each cylinder of a large low-speed main propulsion diesel engine is （）A
the same, whether at sea, or during maneuveringB
adjusted during each hour of operation while at constant RPMC
higher at sea than while maneuveringD
lower at sea than while maneuvering
考题
单选题The diesel engine consumes considerably less fuel than the steam engine for equal output, （） enables a motor-ship to load more cargo.A
whyB
whichC
in whichD
on which
考题
单选题Starting a large low-speed propulsion diesel engine on diesel fuel during cold weather conditions, will be made easier by （）A
increasing the quantity of starting airB
increasing the lube oil pressureC
heating the engine fuel supplyD
heating the engine coolant
考题
单选题Which of the listed diesel engine operating conditions should be checked immediately after any diesel engine is started?（）A
Exhaust temperatureB
Lube oil levelC
Lube oil pressureD
Water level in the expansion tank
考题
单选题A thrust bearing is used with a propulsion diesel engine to （）.A
control axial movement of the crankshaftB
transmit engine thrust to the propeller shaftC
absorb vibrations in the propeller shaftingD
prevent propeller thrust from being transmitted to the hul
考题
单选题Proper lubrication of the main bearings is more easily obtained in a single acting, four-stroke/cycle diesel engine than in a tow-stroke/cycle diesel engine because（）.A
The direction of pressure on the journal in four-stroke engine is continuouslyB
positive feed lubricators are installed on all bearings of four-stroke engine, whereas as a splash feed system is used on tow-stroke engineC
four-stroke engines usually utilize a heavier grade of oil than tow-stroke enginesD
Low-stroke engines usually consume less lube oil than four-stroke engines
考题
单选题The most practical way of detecting an overload in one cylinder of an operating large, low-speed ,main propulsion diesel engine is to （）A
check the cylinder exhausts for black smokeB
listen for combustion knock in that cylinderC
isolate each cylinder and inspect the injectorD
check the cylinder exhaust temperature frequently
考题
单选题What is an advantage of diesel over steam turbine propulsion? （）A
Less fuel consumption per SHPB
Diesel fuel costs less than bunker C or its equivalentC
Less routine maintenance requiredD
Less weight per SHP
考题
单选题When attempting to start a main propulsion diesel engine, the engine, the engine turns at the proper speed but will not startYou should check the（）A
starting air pressureB
scavenge air pressureC
over-speed tripD
banjo oiler line
考题
单选题If the valve tappets in a diesel engine are set at greater clearances than those specified by the engine manufacturer, those valves will （）A
open late and close earlyB
open late and close lateC
fail to open when the engine is coldD
fail to open at normal operating temperature
考题
单选题In a large, slow-speed, main propulsion diesel engine, which of the parts listed is under tension when the engine is running?（）A
Bed plateB
ColumnC
EntablatureD
Tie rod
考题
单选题A large, low-speed, main propulsion diesel engine uses sea water to directly cool the （）.A
cylinder headsB
exhaust valvesC
scavenging airD
injectors
考题
单选题In a diesel engine jacket water cooler, with seawater cooling the fresh water, the（）A
sea water temperature must never be warmer than 40℃B
jacket water pressure should always be greater than the sea water pressureC
jacket water temperature must always be less than 60℃D
jacket water pressure must always be less than the sea water pressure
考题
单选题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 （）A
engine support vibration isolatorB
detuner or viscous fluid damperC
lightened crankshaft flywheelD
spherically seated crankshaft bearing
考题
单选题A naturally aspirated diesel engine at full throttle will have an intake manifold pressure （）A
slightly less than atmospheric pressureB
approximately equal to exhaust manifold pressure at all timesC
that is widely fluctuating constantlyD
decreasing as engine load increases
考题
单选题A two-stroke/cycle diesel engine requires less starting air than a four-stroke/cycle diesel engine, of equal displacement, because the two-stroke/cycle diesel engine（）A
has little or no internal frictionB
has a lower effective compression ratioC
operates with scavenge air under a positive pressureD
operates without energy absorbing intake and exhaust strokes
考题
单选题What causes diesel fuel to be ignited in the cylinder of an operating diesel engine?（）A
Spark plugB
Heat of compressionC
CarburetorD
Glow plug
考题
单选题Which of the following statements concerning the lubrication of diesel propulsion engines used in vessels over 300 gross tons is most accurate?（）A
Lubrication systems using engine driven lube oil pumps do not require any additional independent arrangement when such arrangements have been proven reliableB
The use of engine driven pre-lube pumps is permitted on vessels with propulsion systems developing less than 500 shaft horsepowerC
When forced lubrication is used for propulsion engines, one independently driven stand-by pumps is to be provided in addition to the necessary pumps for normal operationD
Lubrication systems where two oil coolers are fitted require a minimum of two temperature control devices which may be actuated by similar sensors
考题
单选题In a main propulsion turbocharged diesel engine, the speed of the turbocharger varies according to the （）A
governor droopB
speeder spring tensionC
fuel rack lagD
load on the engine
考题
单选题Operating a diesel engine for prolonged periods, with a closed freshwater cooling system, at temperatures lower than the normal design temperature can cause （）.A
the formation of sulfuric acidB
a decrease in lube oil viscosityC
a decrease in cooling water pHD
a thermostat failure
考题
单选题An indication of an overloaded main propulsion diesel engine is （）A
white smoke in the exhaustB
high exhaust gas pyrometer readingsC
sparks in the exhaustD
blue smoke in the exhaust
考题
单选题Which of the following conditions may need to be reduced when operating a large, low speed, main propulsion, diesel engine at low loads?（）A
Injection pressuresB
Control air supply pressureC
Cooling water flow through after-coolersD
Lube oil temperature
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