单选题Starting air for auxiliary engines may be taken directly from the main reservoirs or through ().Aan auxiliary reservoirBa controlling air bottleCan emergency air compressorDa main air compressor
单选题
Starting air for auxiliary engines may be taken directly from the main reservoirs or through ().
A
an auxiliary reservoir
B
a controlling air bottle
C
an emergency air compressor
D
a main air compressor
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相关考题:
Main engines as well as auxiliary engines operating on heavy fuel should have continuousoon the lubricating oil, either according tothebypass or batch principles A.filteringB.centrifugingC.depositingD.operating
If the engine does not start on air, it may be due toA.low compression of the fuel pumpsB.incorrect timing of fuel pumpsC.the starting air valves stuckD.air-locks in fuel oil pipeline
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
Vessels having main engines arranged for air starting are to be provided with at least__.A.one automatic drain serving both containersB.two air starting containers of approximately equal sizeC.one control air container and one starting air containerD.one additional means of starting the main engine
In an operating diesel engine, which of the following conditions is an indication of a leaking air starting valve?A.Noise coming from that air starting valveB.Continuous operation of the starting air compressorC.Zero air pressure in the air starting systemD.Overheated starting air pipe to the cylinder head
If the engine does start on air, but combustion does not immediately begin, the cause may be _____.A.failure of the fuel pumpsB.starting air pressure too lowC.stop valve in air line closedD.the turning gear still engaged
题干材料:Due to the large amount of heat picked up by the air in boiler and engine rooms, it would be impracticable to maintain ambient conditions within the comfort zone by air conditioning or any other means. The normal practice is to provide copious mechanical ventilation; in boiler rooms, the quantity is equated to the combustion requirements, while in a motor ship engine room the supply may be 25-50% in excess of the requirements of the engines.The axial flow fan is particularly suited to handle these large air volumes at the moderate pressures required, while of course the “straight-through” flow feature places it at an advantage over the centrifugal fan.The increasing adoption of automation, with the provision of a separate control room makes less significant the fact that comfort conditions cannot be maintained in the engine room all the time.问题:Which of the following devices should be taken to maintain ambient conditions of the boiler and machinery space?A.air compressorB.air coolerC.air-conditioning plantD.mechanical ventilation plantIn a motor vessel, the air quantity which the engine room need is_______ of the requirements of the engines.A.less than 25-50%B.more than 125-150%C.more than 25-50%D.less than 125-150%According to this passage, which of the following statements is true?A.In boiler and machinery spaces, there is the air conditioningB.In the boiler rooms the requirement of air volume should meet 25-50% of combustion requirementC.To maintain the comfort zone in the separate control room the air conditioning plant should be fittedD.The comfort conditions can be maintained in the engine room all the timeAt the middle pressure and large air quantity,_________ is more suitable.A.an axial flow fanB.a radial flow blowerC.a centrifugal fanD.an auxiliary blower请帮忙给出每个问题的正确答案和分析,谢谢!
单选题Vessels having main engines arranged for air starting are to be provided with at least ()Aone automatic drain serving both containersBtwo air starting containers of approximately equal sizeCone control air container and one starting air containerDone additional means of starting the main engine
单选题Propulsion engines and the vast majority of auxiliary generator engines are designed to allow a generous through-flow of scavenge air in order to control ()Athe lubricating oil consumptionBthe turbine blade temperatureCthe flow rate of fuelDscavenge air pressure
单选题The opening or closing of the cylinder starting valve is controlled by ().Athe starting air distributorBthe cut-off valve on the air mainCthe main starting valveDthe air bottle control valve
单选题Which of the following may cause that an engine doesnt turn on starting air?()Atoo low starting air pressureBmain starting valve closedCneither A nor BDA and B
单选题The total starting air capacity required for reversible main engines is to be sufficient for at least ().Asix consecutive startsBeight consecutive startsCten consecutive startsDtwelve consecutive starts
单选题Which of the following may lead to the engine NOT to start on air?()Astarting air pressure too highBcorrect timing of starting air valvesCthree of the six starting valves stuckDthe turning gear disengaged
单选题Which of the following methods is used to prevent throttling of compressed air through the diesel engine air starting valves?()AHolding the valve open for a long periodBIncreasing the starting air pressure usedCOpening the stating air valve quicklyDReducing the starting air valve size
单选题Which of the following may cause that an engine doesnt run on starting air?()Atoo low starting air pressureBmain start valve closedCneither A nor BDA and B
单选题Main engines as well as auxiliary engines operating on heavy fuel should have continuous on the lubricating oil, either according to the bypass or batch principles()AfilteringBcentrifugingCdepositingDoperating
单选题Cold weather starting of a diesel engine may be made easier by()Adecreasing the compression ratioBusing a special fuel having a high ignition temperatureCincreasing the starting air supplyDheating the jacket water
单选题The booster pump, which supplies diesel oil to() , should have a possibility of being powered by compressed air or by emergency power.Athe main enginesBthe auxiliary enginesCthe emergency generator engineDthe auxiliary engines and the main engine(s)
单选题If the engine does not start on air, it may be due to ()Alow compression of the fuel pumpsBincorrect timing of fuel pumpsCthe starting air valves stuckDair-locks in fuel oil pipeline
单选题Starting air for auxiliary engines may be taken directly from the main reservoirs or through ().Aan auxiliary reservoirBa controlling air bottleCan emergency air compressorDa main air compressor
单选题An electric heater built into some smaller diesel engines is used to ().Araise lube oil viscosity for easier starting in cold weatherBincrease air inlet temperatureCincrease compression ratioDincrease jacket water temperature for easier starting in cold weather
单选题When starting air is admitted, a diesel engine turns over very slowly without firingThe cause may be ()Aan obstruction in an cylinderBwater accumulation in some engine cylindersClow starting air pressureDlow scavenge air pressure
单选题In an operating diesel engine, which of the following condition is an indication of a leaking air starting valve?()Anoise coming from that air starting valveBcontinuous operation of the starting air compressorCzero air pressure in the air starting systemDoverheated starting air pipe to the cylinder head
单选题The closing of the exhaust valves used on a modern, large, low-speed, main propulsion diesel engine may be directly provided by ().Alarge conical springsBcompressed air pressureChydraulic pressureDexhaust gas pressure
单选题When an engine is starting and has got a sufficiently high speed, say about 20 rpm,()Athe starting air supply is cut off and fuel is injected into the cylindersBthe fuel feeding is cut off and the turning gear is put inCthe starting air supply is cut off and turning gear is taken outDthe electric blower is shut down and fuel is injected into the cylinders
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单选题An auxiliary reservoir for starting auxiliary engines should be kept at ().Alow pressure at all timesBfull pressure at all timesClow pressure at intermittenceDfull pressure at intermittence
单选题Failure to open the diesel engine test cocks after a long period of shutdown, prior to starting may result in ()Aan air bound fuel systemBdamage to cylinder heads and pistonsCexcessive fuel injectionDexcessive air valve lift