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单选题
The starting air system usually has （） to prevent starting if anything is not in order.
A
stop valves
B
interlocks
C
non-return valves
D
air vents
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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
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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
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考题
Which of the following utilities would a technician use to prevent a service from starting duringsystem startup?（）A、Event ViewerB、System File CheckerC、MSCONFIGD、Task Manager
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A diesel engine is turned at normal cranking speed, but fails to fireThis can occur from （）A
low lube oil temperatureB
low starting air temperatureC
air in the fuel injectionD
water in the starting air system
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（） device is provided to prevent starting air from being admitted to the cylinder before the reversing is completed.A
An automaticB
A transmissionC
A self-regulatingD
An interlocking
考题
单选题The starting air system usually has （） to prevent starting if anything is not in order.A
drain cocksB
vent valvesC
counteractsD
interlocks
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
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单选题A diesel engine is turned at normal cranking speed and no ignition occursThis could be the result of （）A
low lube oil temperatureB
low starting air temperatureC
air bubbles in the fuel oil systemD
water in the starting air system
考题
单选题The compressed air is admitted to each cylinder through a cam operated by starting air valve when the piston has just passed its （）.A
BDCB
TDCC
BBDCD
ATDC
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In the starting system, the automatic valve is controlled by（）, and the cylinder start valves are controlled by（）A
pilot air；pilot airB
handle；solenoidC
handle；pilot air coming through the distributorD
solenoid；pilot air coming through the distributor
考题
单选题Each cylinder has one starting valve which is usually opened by air pressure and closed by （）A
nuts and boltsB
new jointsC
spring forceD
sealing rings
考题
单选题The pressure of pilot air is usually （） than that of starting air.A
higherB
lowerC
lowD
high
考题
单选题The primary task of the compressed air system is to deliver the starting air necessary for （）A
starting the MEB
starting the emergency electric alternatorC
driving the main turbineD
driving the turbocharger
考题
单选题During （）, the starting air valves should be closed to prevent the engine from turning.A
overhaulB
runningC
blowing downD
All of the above are correct
考题
单选题Pump up the starting air reservoirs to their maximum pressure and （）the air reservoirs and air system.A
openB
closeC
drainD
vent
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When the starting air valve closes on one cylinder, another starting air valve has （） opened on another cylinder whose piston has just commenced its downward stroke.A
justB
nearlyC
merelyD
already
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
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