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单选题
Precision engine bearing inserts are manufactured with a small portion of the bearing ends extending beyond the bearing housing or capsThe installation process of these bearings requires sufficient （）.
A
overlap
B
crush
C
lap or lead
D
protrusion
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更多 “单选题Precision engine bearing inserts are manufactured with a small portion of the bearing ends extending beyond the bearing housing or capsThe installation process of these bearings requires sufficient （）.A overlapB crushC lap or leadD protrusion” 相关考题
考题
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 hull
考题
The bearing of tailshaft sealing equipment which adopts the oil nature circulation is hot, the reason isA.the rotate speed fluctuationB.the ventilation tube cloggedC.the main engine accelerate so fastD.stormy waves
考题
材料：Spark erosion is caused by a voltage discharge between the main bearing and journal surface. The cause of the potential is the development of a galvanic element between the ship’s hull, sea water, and the propeller shaft/crankshaft.The oil film acts as a dielectric. The puncture voltage in the bearing depends on the thickness of the oil film. With increasing engine ratings, the specific load in the main bearing is increased. his will reduce the oil film thickness, and enable the discharge to take place at a lower voltage level.Since the hydrodynamic oil film thickness varies through a rotation cycle, the discharge will take place at roughly the same instant during each rotation cycle, i.e. when the film thickness is at its minimum. The roughening will accordingly be concentrated in certain areas on the journal surface. In the early stages, the roughened areas can resemble pitting erosion. but later, as the roughness increases, the small craters will scrape off and pick up white metal-hence the silvery white appearance.Therefore, to ensure protection against spark erosion, the potential level must be kept at maximum 80 mV, which is feasible today with a high efficiency earthing device. If an earthing device is installed, its effectiveness must be checked regularly. Spark erosion is only observed in main bearings and main bearing journals.问题：According to the paragraph one, a voltage between the main bearing and journal surface is produced by______.A.propeller rotationB.leakage from M/E electric control unitC.a galvanic elementD.friction between the main bearing and journal surface______engine ratings increase, the hydrodynamic oil film between the main bearing and journal surface is______.A.The lower/thinnerB.The higher/the thickerC.The lower/thickerD.The higher/thinnerWhen will the spark erosion take place on the journal surface during each rotation cycle?A.when the film thickness is at its minimumB.when the film thickness is at its maximumC.when the engine is on its compression strokeD.when the engine is on its exhaust strokeDuring the engine room watch keeping, which equipment must be noted to ensure protection against spark erosion?A.the antifouling plantB.the earthing deviceC.the main engine electric heating coilsD.the shaft generator请帮忙给出每个问题的正确答案和分析，谢谢！
考题
单选题Diesel engine main and connecting rod precision bearings are made in halvesEach half exceeds one-half the bearing circumference by a small amountThe small amount is termed （）.A
clearanceB
crushC
pitchD
thrust
考题
单选题Worn main bearing will cause the compression ratio of an auxiliary diesel engine to（）A
increaseB
decreaseC
remain the sameD
increase on compression decrease on expansion
考题
单选题As to the bearing, of the following, which statement is not true?（）A
ff overheat is found, the engine must be stopped for inspectionB
Much heat of the crankcase door indicates that the bearing is overheatedC
If bearing clearance is too large, knocking will be heard in the crankcaseD
If bearing clearance is too large or too small, the white metal may be melted
考题
单选题In the management of the shafting, because（） carry heavy load and caused high temperature easily, it should be paid attention.A
the bearing near to the diesel engineB
the intermediate bearing near to the thrust bearingC
the intermediate bearing near to the sterntubeD
the bearing located at the middle of the diesel engine and the sterntube
考题
单选题In an engine with a pot-shaped piston, some lubricating oil from the main bearing will pass along a drilled passage in the crankshaft to the bottom end bearing and then up a connection rod to the （）.A
crossheadB
crankpinC
crank journalD
gudgeon pin
考题
单选题In an engine with a pot-shaped piston, some lubricating oil from the main bearing will pass along a （） in the crankshaft to the bottom end bearing andthen up a connection rod to the gudgeon pin.A
telescopic pipesB
large boreC
drilled passageD
tied rod
考题
单选题Which of the following operating conditions can occur when shims are removed from the joint between the foot of a marine type diesel engine connecting rod and the bearing box?（）A
Decreased connecting rod bearing clearanceB
Increased connecting rod bearing clearanceC
Decreased compression ratioD
Increased compression ratio
考题
单选题The purpose of an oil mist detector in a main propulsion diesel engine is to warn of （）A
excessive mist density in the crankcasesB
excessively high crankcase vacuumC
excessively high bearing temperatureD
excessive carbon buildup in the lube oil
考题
单选题The bearing of tailshaft sealing equipment, which adopting the oil nature circulation is hot, the reason is（）A
the rotate speed fluctuationB
the ventilation tube cloggedC
the main engine accelerate so fastD
stormy waves
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You are inspecting the lower main precision bearings on a diesel engine.You observe that about half the thin Babbitt linings are of a milky white colourThis condition is caused by （）A
large dirt particles in the oil supplyB
insufficient lubricating oil and overheatingC
normal wearD
water contamination of the lube oil
考题
单选题Small crack in the crankshaft bearing surface of a diesel engine are an indication of（）A
corrosion frettingB
insufficient lubricationC
abnormal wearD
fatigue failure
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The bedplate must be rigid enough to support the weight of the rest of the engine, and maintain the crankshaft, which sits in the bearing housings in the （）, in alignment.A
longitudinal girdersB
transverse girdersC
fore girdersD
aft girders
考题
单选题Heat for igniting the fuel oil in the cylinder of a diesel engine is generated by the （）A
electronic ignition systemB
compression of air by the pistonC
friction in the fuel injectorD
fuel oil bearing system
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A grease gun is generally used to lubricate a （）.A
condensate pump ball bearingB
main shaft bearingC
main turbine bearingD
diesel engine wrist pin bearing
考题
单选题High lube oil temperatures developing in a diesel engine can result from（）A
high oil pressureB
excessive bearing end playC
plugged oil control ringsD
engine overload
考题
单选题To determine the main bearing clearance of a propulsion diesel engine, you should measure the main bearing shell using a ball anvil outside micrometer and measure the crankshaft journal using a/an （）A
telescopingB
ring ‘snap’ gaugeC
inside vernier caliperD
outside micrometer
考题
单选题While inspecting the main bearings on a diesel engine you find impregnated dirt and scratches in the bearing surface you would, therefore, suspect that （）A
the bearing had been overheatedB
water was present in the oilC
the lube oil was not being properly filteredD
the maximum allowable bearing pressure had been exceeded
考题
单选题Lubricating oil used in a diesel engine serves to（）A
reduce the wear of bearing surfacesB
cool the bearing surfacesC
assist in sealing bearing surfacesD
all of the above
考题
单选题A wobbling tail shaft is an indication of（）.A
shallow waterB
an engine that is misfiringC
a tight tail shaft glandD
worn stern bearing or misalignment
考题
单选题A possible cause for an individual piston to knock when at TDC on a slow-speed, two-stroke/cycle main propulsion diesel engine could be due to （）A
early fuel injectionB
excessive bearing play within the running gearC
overloading of the cylinderD
all of the above
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