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单选题
Some medium and high-speed diesel engines require reduction gear units to provide a useful propeller speedIn most reduction gears, the bull gear（）
A
must churn the oil in the sump
B
is connected to the propeller shaft
C
is driven at the highest RPM
D
compensates for alignment variations between the engine and pinion gear
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更多 “单选题Some medium and high-speed diesel engines require reduction gear units to provide a useful propeller speedIn most reduction gears, the bull gear（）A must churn the oil in the sumpB is connected to the propeller shaftC is driven at the highest RPMD compensates for alignment variations between the engine and pinion gear” 相关考题
考题
Diesel engine electric starting motors generally require heavier duty motors and motors and operate at higher voltages than comparable starting motors for gasoline engines due to _____________.A.higher speed requiredB.flywheel-effectC.lower starting temperaturesD.higher compression pressures
考题
Lubrication for the main reduction gears used with diesel engines is usually supplied byA.oil from the main engine sumpB.an independent lube oil systemC.the stern bearing head tankD.the stem bearing sump tank
考题
单选题One major disadvantage of a low-speed diesel as compared to a steam main-propulsion system is（）.A
the extra weight required for the diesel reduction gearingB
a minimum speed for the engines that limits the minimum speed of the vesselC
the higher fuel consumption per SHPD
the low efficiency of the system when a controllable pitch propeller is used
考题
单选题Heat damage to fuel injection nozzles on small high-speed diesel engines, can be prevented by（）A
employing fuel oil as a cooling mediumB
preventing hard carbon deposit on nozzle tipsC
avoiding fuel oil temperature exceeding builder’s specificationD
ensuring good metallic contact between nozzles and cylinder heads
考题
单选题The over-speed trip device installed in some diesel engines is automatically actuated by（）A
spring forceB
hydraulic pressureC
centrifugal forceD
mechanical linkage
考题
单选题The majority of medium speed and high speed marine diesel engines for main or auxiliary drive operate on the （） cycle.A
two-strokeB
four-stokeC
long-strokeD
short-stroke
考题
单选题The reversing cams of some four-stroke/cycle diesel engines are brought into position by （）A
sliding the camshaft along its axisB
rotating the cam 180C
rotating the cam followers 180D
moving the idler sprockets in the drive chain
考题
单选题Diesel engine electric starting motors generally require heavier duty motors and motors and operate at higher voltages than comparable starting motors for gasoline engines due to（）A
higher speed requiredB
flywheel-effectC
lower starting temperaturesD
higher compression pressures
考题
单选题（）, so they are widely used on board ship nowadays.A
Diesel engines have more advantages in comparison with gasoline enginesB
Diesel engines have more advantages in comparison to gasoline enginesC
Gasoline engines have more advantages in comparison with diesel enginesD
Gasoline engines have more advantages in comparison to diesel engines
考题
单选题One end of a cylinder for a medium or high-speed diesel engine is sealed by the piston and rings, the other end is sealed by the （）A
crankcaseB
cylinder headC
valve coverD
engine frame
考题
单选题Proper lubrication of the main bearing is more easily obtained in a single acting four-stroke/cycle diesel engine than in a single acting two-stroke/cycle diesel engine because （）A
bearing pressure in a four-stroke/cycle acting single diesel engine is continually reversedB
bearing pressure in a two-stroke/cycle single acting diesel engine is continually reversedC
the maximum bearing pressure is higher in a single acting two-stroke/cycle diesel engineD
two-stoke/cycle diesel engines require more complicated lubrication piping
考题
单选题In conventional systems, the injection pressure（）, while it’s（）in common rail diesel engines.A
fluctuates with the engine speed to some extent, independent of the engine speedB
keeps constant at all engine speed, dependent on the engine speed to some extentC
keeps constant at all engine speed, independent of the engine speedD
is decided by the engine speed, constant at all engine speed
考题
单选题The reason why more and more of the large merchant vessels are being powered by medium-speed diesel engines is （）.A
they operate between 150 and 450 rpmB
they are connected to the propeller by gearingC
their smaller size and weightD
they can be connected directly to the propeller without gearing
考题
单选题Some diesel engines are supercharged with a （）A
slam chargerB
turbochargerC
fuel atomizerD
fuel injector
考题
单选题When used with reversing reduction gears, medium-speed diesel engines should be bolted to their foundations with fitted bolts at the drive end and clearance(loosely fitted) bolts in other locations √This is done to （）A
maintain alignment when the ship’s hull is working in heavy seasB
ensure engine vibrations correspond to the natural frequency of the hullC
permit the engine to expand away from the driven equipment as the engine heats up and expandsD
maintain engine thrust bearing clearances
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The crankshafts of medium speed engines are almost invariably solid （） from a single piece of steel.A
forgedB
castC
madeD
shrunk
考题
单选题Although the crankshafts of medium diesel engines appear to be robust, they rely on the support of （） to develop their full strength.A
the piston rodsB
the crank throwsC
the thrust bearingsD
the main bearings
考题
单选题An electric heater built into some smaller diesel engines is used to （）.A
raise lube oil viscosity for easier starting in cold weatherB
increase air inlet temperatureC
increase compression ratioD
increase jacket water temperature for easier starting in cold weather
考题
单选题Prior to starting most medium-speed propulsion diesel engines, which of the procedures listed should be observed?（）A
The expansion tank should be topped offB
The thermostatic water regulating valves should be manually openedC
The fuel filters should be changedD
The engine should be turned over slowly with the indicator cocks open
考题
单选题Pistons of marine medium speed diesel engines may be made of （） in order to keep the weight down for balancing purpose at high speed.A
leadB
forged steelC
alloy steelD
aluminum alloy
考题
单选题Valve cages are used on some large diesel engines to （）A
reduce wear on the valve stemB
permit the use of alloy valve seat materialsC
reduce heat transfer from the valve seatD
facilitate valve removal for servicing
考题
单选题All diesel engines are classified as（）.A
four cycleB
compression ignitionC
vacuum ignitionD
external combustion
考题
单选题A waste heat boiler is installed on some diesel propelled vessels to （）.A
provide steam for emergency propulsionB
provide steam for the turbo-generatorC
heat the waste water tanksD
steam for warming engines
考题
单选题The main operating characteristic of diesel engines which distinguishes them from other internal combustion engines is the （）A
method of supplying airB
cooling systemC
method of igniting fuelD
valve operating mechanism
考题
单选题Some diesel engines are fitted with a thermometer in the cooling water outlet from each cylinderIf the cooling water temperature from all cylinders begins to rise above normal, you should suspect （）A
increase blow-by in all cylindersB
incomplete combustion in all cylinderC
overloading in all cylindersD
insufficient fuel delivery to all cylinders
考题
单选题In some modern large diesel engines, which of the following is used as the support for the main bearings?（）A
BedplateB
BlockC
BaseD
Sump
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