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单选题
Critical speed in diesel engines occurs when engine torque pulsations become （）
A
opposed to the crankshaft rocking couple
B
resonant with the crankshaft natural frequency
C
critical fore and aft crankshaft vibrations
D
horizontal whipping motions of the crankshaft
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考题
When transmitted by a reduction gear, diesel engine speed is reduced and the torque available for workA.remains the sameB.is reducedC.is increasedD.is eliminated
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In reducing engine speed to an efficient propeller speed by the use of reduction gears, _______.A.speed and torque are both reducedB.speed is reduced and torque remains unchangedC.speed is reduced and torque is increasedD.speed is sometimes unchanged while torque is increased
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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
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单选题（）are increasingly used as main engine on merchant vessels, because they have a high Hp/Weight ratio.A
Slow speed diesel enginesB
Medium-speed diesel enginesC
Steam enginesD
Gasoline engines
考题
单选题When transmitted by a reduction gear, diesel engine speed is reduced and the torque available for work （）A
remains the sameB
is reducedC
is increasedD
is eliminated
考题
单选题In large, low-speed, main propulsion diesel engine, position ring groove wear usually occurs at the（）A
top of the ring grooveB
back of the ring grooveC
bottom of the ring grooveD
piston ring end clearance
考题
单选题If keep the fuel injection of main engine unchanged when ship is fouled, that will causeⅠ.The speed of main engine to be reduced Ⅱ.Ship speed to be reduced Ⅲ.The resistance torque of propeller to be increased Ⅳ.Trim at stern to increase（）A
Ⅰ + ⅡB
Ⅰ ~ ⅢC
Ⅰ ~ ⅣD
Ⅰ + Ⅱ + Ⅳ
考题
单选题An over-speed trip stops a diesel engine when the engine （）A
runs out of fuelB
has low lubricating oil pressureC
exceeds a set maximum speedD
has high cooling water temperature
考题
单选题For most diesel propulsion and generator engines, the over-speed trip device will stop the engine by （）A
moving the governor control to stopB
shutting off the lubricating oil supplyC
tripping the governor emergency stop leverD
shutting off the fuel supply
考题
单选题A diesel engine which is rated for normal operation at a crankshaft speed of 800 RPM, is commonly classed as a （）.A
slow-speed dieselB
medium-speed dieselC
high-speed dieselD
constant-speed diesel
考题
单选题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（）.A
caused by retarded injection timingB
caused by a mechanical defect in one cylinderC
caused by high fuel injection pressuresD
normal for these conditions
考题
单选题Which of the following procedures should be carried out when a large, low-speed, diesel engine is operated with one cylinder secured?（）A
Lubrication to the defective cylinder should be increasedB
Cooling water temperature to the engine should be increasedC
Only the turbocharger speed should be reducedD
Engine speed should be reduced
考题
单选题The main function of tie rods in the construction of large, low speed diesel engines is to（）.A
stiffen the bedplate in way of the main bearings to increase the engines longitudinal strengthB
accept most of the tensile loading that results from the firing forces developed during operationC
mount the engine frame securely to the hull to prevent shaft coupling misalignmentD
connect the crosshead solidly to the piston rod
考题
单选题The size of the exhaust valve opening is （）A
most critical in a four-stroke cycle diesel engineB
most critical in a two-stroke/cycle diesel engineC
most critical in a four-stroke/cycle diesel engine if it is turbochargedD
of equal importance in a two-stroke/cycle diesel engine as in a four-stroke/cycle diesel engine
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When the vessel on the full speed ahead, if full astern immediately （） the main engine start astern and fuel injection.A
after the thrust power is zeroB
after the torsion is zeroC
surpass the critical point on the water turbo phaseD
after the speed is zero
考题
单选题The device used to limit engine torque at various engine speeds is called a （）A
speed limiting governorB
variable speed governorC
constant speed governorD
load limiting governor
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When the general alarm is sounded continuously, the engine room personnel should （）.A
proceed to their man overboard stationsB
start the fire pumpC
put on lifejackets and go to their abandon ship stationsD
secure the propulsion diesel engines and evacuate the engine room
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If a crankcase explosion occurs in a diesel engine, you should stop the engine and（）A
immediately open all crankcase relief portsB
increase crankcase exhauster speed to draw cool air into the engineC
allow the engine to cool naturallyD
increase crank case scavenge air to remove unburned gases
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After-cooling of a turbocharged diesel engine will result in （）A
higher torque but lower brake horsepowerB
lower torque but higher brake horsepowerC
higher torque and lower brake horsepowerD
lower torque and higher brake horsepower
考题
单选题If the speed of a turbocharged diesel engine is maintained constant the turbocharger speed will （）A
decrease until the engine speed increasesB
increase as the load increasesC
decrease as the loadD
increases remain unchanged
考题
单选题When comparing different fuels for different engines, the ignition quality of diesel fuel oils becomes a less critical consideration as （）A
the amount of lube oil additives increaseB
piston speeds increaseC
injection pressure decreaseD
engine speeds decrease
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