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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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更多 “单选题Starting air for auxiliary engines may be taken directly from the main reservoirs or through （）.A an auxiliary reservoirB a controlling air bottleC an emergency air compressorD a main air compressor” 相关考题
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
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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
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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
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
考题
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
考题
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
考题
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！
考题
单选题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
考题
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 （）A
the lubricating oil consumptionB
the turbine blade temperatureC
the flow rate of fuelD
scavenge air pressure
考题
单选题The opening or closing of the cylinder starting valve is controlled by （）.A
the starting air distributorB
the cut-off valve on the air mainC
the main starting valveD
the air bottle control valve
考题
单选题Which of the following may cause that an engine doesnt turn on starting air?（）A
too low starting air pressureB
main starting valve closedC
neither A nor BD
A and B
考题
单选题The total starting air capacity required for reversible main engines is to be sufficient for at least （）.A
six consecutive startsB
eight consecutive startsC
ten consecutive startsD
twelve consecutive starts
考题
单选题Which of the following may lead to the engine NOT to start on air?（）A
starting air pressure too highB
correct timing of starting air valvesC
three of the six starting valves stuckD
the turning gear disengaged
考题
单选题Which of the following methods is used to prevent throttling of compressed air through the diesel engine air starting valves?（）A
Holding the valve open for a long periodB
Increasing the starting air pressure usedC
Opening the stating air valve quicklyD
Reducing the starting air valve size
考题
单选题Which of the following may cause that an engine doesnt run on starting air?（）A
too low starting air pressureB
main start valve closedC
neither A nor BD
A and B
考题
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（）A
filteringB
centrifugingC
depositingD
operating
考题
单选题Cold weather starting of a diesel engine may be made easier by（）A
decreasing the compression ratioB
using a special fuel having a high ignition temperatureC
increasing the starting air supplyD
heating the jacket water
考题
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.A
the main enginesB
the auxiliary enginesC
the emergency generator engineD
the auxiliary engines and the main engine(s)
考题
单选题If the engine does not start on air, it may be due to （）A
low compression of the fuel pumpsB
incorrect timing of fuel pumpsC
the starting air valves stuckD
air-locks in fuel oil pipeline
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When starting air is admitted, a diesel engine turns over very slowly without firingThe cause may be （）A
an obstruction in an cylinderB
water accumulation in some engine cylindersC
low starting air pressureD
low scavenge air pressure
考题
单选题In an operating diesel engine, which of the following condition 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
考题
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 （）.A
large conical springsB
compressed air pressureC
hydraulic pressureD
exhaust gas pressure
考题
单选题When an engine is starting and has got a sufficiently high speed, say about 20 rpm,（）A
the starting air supply is cut off and fuel is injected into the cylindersB
the fuel feeding is cut off and the turning gear is put inC
the starting air supply is cut off and turning gear is taken outD
the electric blower is shut down and fuel is injected into the cylinders
考题
单选题When occurring a fire in the scavenge air box, the following measures should be taken except for（）A
reducing speed to SLOW and asking bridge for permission to stopB
stopping the fuel oil supplyC
switching-on the auxiliary blowersD
putting the scavenge air box fire extinguishing equipment into function
考题
单选题An auxiliary reservoir for starting auxiliary engines should be kept at （）.A
low pressure at all timesB
full pressure at all timesC
low pressure at intermittenceD
full pressure at intermittence
考题
单选题Failure to open the diesel engine test cocks after a long period of shutdown, prior to starting may result in （）A
an air bound fuel systemB
damage to cylinder heads and pistonsC
excessive fuel injectionD
excessive air valve lift
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