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单选题
Differential needle valves used in fuel injectors are directly closed by（）
A
cam action
B
spring force
C
fuel oil pressure
D
firing pressure
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Cooling water is circulated through______in some injectors.A.the nozzleB.the nozzle tipC.the internal passagesD.the fuel re-circulated
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Springs in fuel injectors will become not strong enough to work because______.A.the injector opens at a lower pressure than designedB.the needle valve and seat wear outC.the nozzle holes wear outD.long time in use
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Injectors for use with heavy fuel oil must be cooled by either water or light oil to_____.A.prevent heat corrosion to internal componentsB.increase fuel delivery rate and economyC.prevent pre-ignitionD.avoid carbonization of the nozzle tips
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单选题The needle valve in a fuel valve will （） when the fuel pressure action on the needle valve tapered face exerts a force lower than that of the spring compression.A
be jammedB
be openedC
be seatedD
be broken
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单选题Maintaining the close tolerances in diesel fuel pumps and injectors requires the use of（）.A
fuel/water separatorsB
day tanksC
injector test standD
fuel filters
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单选题Which of the valves listed should be used either in the fully opened or the fully closed position?（）A
A gate valveB
A globe valveC
Any check valveD
Any needle valve
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单选题If the needle valve in a fuel injection nozzle sticks open （）.A
no fuel will be delivered through the nozzleB
the nozzle will overheat and crackC
time of injection will changeD
fuel will leak into the drain line
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单选题If the engine can be started and maneuvered on high viscosity fuel, the （）of the fuel reaching the injectors should be raised to such a point that the viscosity is less than the required value, ie27c St.A
pressureB
temperatureC
viscosityD
density
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单选题During the fuel injection period, fuel pressure must exceed cylinder gas pressure to （）.A
ensure penetration and distribution of the fuel in the combustion chamberB
ensure the needle valve is flushed clean during each injectionC
prevent combustion gas blowback into the open needle valveD
prevent reflected pressure waves when the needle valve closes
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单选题In the cylinder head of a two-stroke/cycle diesel engine, valves are used for（）A
air intakeB
a fuel outletC
cooling water inletsD
exhausting combustion gas
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单选题The needle valve will open when the fuel pressure acting on the needle valve （） exerts a sufficient force to overcome the spring compression.A
tape faceB
tapered faceC
surfaceD
thinner face
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单选题Injectors for use with heavy fuel oil must be cooled by either water or light oil to （）A
prevent heat corrosion to internal componentsB
increase fuel delivery rate and economyC
prevent pre-ignitionD
avoid carbonization of the nozzle tips
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单选题Thermostatic steam pressure reducing valves are used in the fuel oil service system to control the（）A
double bottom fuel oil tank temperatureB
heater supply steam flowC
pressure of the fuel supplied to the burnersD
attemperator steam flow in the heater discharge circuit
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单选题A change in the quality of fuel atomization by a diesel engine fuel injector would be caused by a/an （）A
increase in engine speedB
increase in cylinder turbulenceC
leaking needle valveD
reduction in cylinder turbulence
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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
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air-locks in fuel oil pipeline
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单选题Starting air valves are held firmly on their seats by（）A
cam rollers on the camshaftB
spring forceC
air pressure on top of the valve differential pistonD
air pressure on the bottom of the valve differential piston
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单选题In an elector-hydraulic steering system, rudder shock is limited by（）A
a differential gearB
return springsC
a hydraulic accumulatorD
relief valves
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单选题Faulty operation of diesel engine fuel injection nozzles can be a direct cause of（）.A
excessive fuel nozzle holder coolingB
sediment in the fuel supplyC
distortion of the fuel spray patternD
improper atomization of the fuel
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单选题Movement of the diaphragm or bellows is （） by a linkage to a needle or pointer display to indicate the differential pressure between two sides of the diaphragm or bellows.A
measuredB
recordedC
transferredD
controlled
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单选题Which of the fuel injection systems listed uses a spring loaded differential spray needle valve and individual pump for each cylinder?（）A
Common-rail injectionB
Air injectionC
Jerk pump injectionD
Distribution injection
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单选题Fuel injectors used in heavy fuel oil systems are usually provided with cooling to reduce（）.A
cold corrosion of the nozzlesB
fuel viscosity for better atomizationC
carbon accumulation on the nozzlesD
fuel detonation in the cylinders
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单选题Proper filtering and straining of fuel oil is important because the （）.A
fuel oil pump will over-speed if dirt is not removedB
fuel oil transfer pumps cannot tolerate small amounts of dirt in the oilC
fuel injectors may be damaged by foreign particles in the fuel oilD
dirty fuel will clog the intake air filter
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单选题The direct acting mechanical governor used with some small diesel engines, controls fuel flow to the engine by（）A
governor flyweight action on a pilot valve which controls fuel injectionB
governor flyweight motion acting on fuel controls through suitable linkageC
positioning a butterfly valve in the fuel delivery system positioningD
a servomotor piston attached to the fuel controls
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单选题In some type of two-stroke engines, besides some small holes for（）, starting valve, safety valve, indicator cock, and central opening in each cylinder cover for mounting the（）A
fuel valves；exhaust valveB
exhaust valves；inlet valveC
fuel valves；inlet valveD
exhaust valves；fuel valve
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