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润滑油系统（lubrication system）
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更多 “润滑油系统（lubrication system）” 相关考题
考题
Which of the following statements concerning the lubrication of diesel propulsionengines used in vessels over 300 gross tons is most accurate? ( )A.Lubrication systems using engine driven lube oil pumps do not require any additionalindependent arrangement when such arrangements have been proven reliable.B.The use of engine driven pre-lube pumps is permitted on vessels with propulsionsystems developing less than 500 shaft horsepower.C.When forced lubrication is used for propulsion engines , one independently drivenstandby pumps is to be provided in addition to the necessary pumps for normaloperation.D.Lubrication systems where two oil coolers are fitted require a minimum of twotemperature control devices which may be actuated by similar sensors.
考题
第二组Under normal operation, some lubrication oil mist may be discharged from the air compressor to the air start system. This oil may be from excess compressor cylinder lubrication, from faulty oil scraper rings, or may even be suspended oil vapor contaminating the engine room atmosphere and drawn in at the compressor suction. Oil discharge is kept to a minimum by draining the after cooler, air receiver and starting system. If small quantities of lubrication oil do get passed into the starting air system, they will deposit as thin moist film over internal pipe surfaces but are not readily combustible. If a cylinder non-return valve leak while the engine is in operation, some hot gas, possibly with unburned fuel and cylinder lubrication oil, may be blown through the valve to the adjacent air manifold. With further heating from the leaky valve, this, together with the already deposited oil film, will carbonize and form. incandescent carbon. If starting air is applied to the system while still hot, the high pressure air coming into contact with the burning carbon may cause an explosion. Such an explosion will cause a flame to pass back through the air start pipe system, evaporating the deposited oil film and igniting it in the presence of air. Very high velocities and shockwaves are generated which may rupture pipes and fittings.Alternatively, if excessive oil has entered the air start system, a mixture of air and oil droplets may be discharged through the open cylinder non-return valve during starting. This spray may ignite due to high temperatures in the cylinder, causing a flame through the still open valve to the air manifold.To prevent an explosion, air start valves must be correctly maintained and lubricated to ensure correct timing and free movement with positive closing. Oil in the system must be kept to a minimum, pipe lines must be drained and cleaned internally when necessary and oil discharge from air compressors must be kept to a minimum by good maintenance.The passage is mainly aboutA.crankcase explosionB.scavenge box fireC.starting air pipeD.the danger of explosion in the starting air system
考题
The common method of applying oil to the cylinder walls is by means of small pump assembled in units, known asA.mechanical lubricatorB.lubrication functionC.forced feed systemD.bearing lubrication
考题
Restrictions occurring in the small orifices(孔) of pneumatic control system components can be caused by ______.A.moisture in the compressed air supplyB.excessive dryness in the compressed air supplyC.pressure surging in the compressed air receiverD.insufficient lubrication of the system components
考题
The most serious effect of air trapped in a diesel engine jacket water cooling system is that it ______．A.Causes colloid suspension in the cooling waterB.Reduces the capability of the lubrication systemC.Can form pockets which block the flow of coolant through the systemD.Leads to the scuffing of cylinder walls
考题
The major objective of system configuration management is which of the following?系统配置管理的主要目标是下列哪一个？（）A、system tracking.系统跟踪B、system operations.系统操作C、system maintenance.系统维护D、system stability.系统稳定性
考题
整个丙烷制冷压缩机系统可分为（）A、润滑油压力系统、润滑油过滤系统、润滑油温度系统、负载控制、反循环系统和电动机互锁、前后级控制B、润滑油温度系统、负载控制、反循环系统和电动机互锁，前后级控制C、润滑油压力系统、润滑油过滤系统、润滑油温度系统、负载控制、前后级控制D、润滑油压力系统、润滑油温度系统、负载控制、反循环系统和电动机互锁，前后级控制
考题
单选题Large crosshead type engine generally has two lubrication systems, a function performed only by crankcase oil system is（）A
lubricatingB
coolingC
cleaningD
neutralizing
考题
单选题Increased internal leakage, in addition to poor hydraulic system response,and inadequate lubrication, is the result of （）.A
pump bearings in poor conditionB
excessively worn actuator-piston packingC
broken directional control valve centering springsD
low hydraulic oil viscosity
考题
单选题In a bypass type lubrication system for a diesel engine, the dirty oil line to the centrifuge should be taken from the （）.A
lube oil pump suction lineB
lube oil pump discharge lineC
bottom of the lube oil sumpD
outlet from the lube oil header
考题
单选题Restrictions occurring in the small orifices of pneumatic control system components can be used by （）A
moisture in the compressed air supplyB
excessive dryness in the compressed air supplyC
pressure surging in the compressed air receiverD
insufficient lubrication of the system components
考题
单选题Large marine diesel engines of crosshead construction generally have two systems of lubrication: a total loss system feeding the （） and a recirculation system lubricating the running gear and cooling the piston.A
cylinder liners and piston ringsB
main bearingsC
crankpin bearingsD
turboblower
考题
单选题The most serious effect of air trapped in a diesel engine jacket water cooling system is that it（）.A
causes colloid suspension in the cooling waterB
reduces the capability of the lubrication systemC
can form pockets which block the flow of coolant through the systemD
leads to the scuffing of cylinder walls
考题
单选题Oil pressure in the lubrication system is（）than the static sea water head to ensure that sea water cannot enter the sterntube in the event of seal failure.A
higherB
lowerC
very higherD
very lower
考题
单选题Oil pressure in the lubrication system is （） the static sea water head to ensure that sea water （） the stem-tube.A
lower than；can lubricateB
lower than；can coolC
higher than；can enterD
higher than ；cannot enter
考题
单选题Wristpin bearings are difficult to lubricate because of their oscillating motion and（）A
their free-floating designB
their relatively small sizeC
the reciprocating motion of the pistonD
their position in the lubrication system
考题
多选题IEEE802.1x协议的体系结构包括（）。ASupplicant System客户端BAuthenticator System认证系统CAccount System认证计费系统DAuthentication Server System认证服务器
考题
单选题（）diesel engines generally have two systems of lubrication:（）a total loss system feeding and a circulating system lubricating the running gear and cooling the pistons.A
Large crosshead type；crossheadsB
High speed；the cylindersC
Large crosshead type；the cylindersD
Four-stroke；pistons and cylinders
考题
单选题If you change from a low pour point lubricant to a high pour point lubricant in a refrigeration system, （）.A
compressor lubrication will be improvedB
oil will not leave the crankcaseC
compressor valves will be damagedD
oil may congeal in the evaporator
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