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单选题
If the operating element of a thermostatic valve installed in a diesel engine cooling system malfunctions, it may result in （）
A
a low level in the engine expansion tank
B
excessively high coolant pressure
C
improper temperatures
D
malfunctioning of the jacket water heater
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If the coolant temperature of a closed cooling water system for a diesel enginegradually increases, the trouble usually is( ).A.a broken shaft on the freshwater pumpB.an excessive accumulation of scale in the heat exchangerC.an incorrect thermostatic element operating rangeD.lube oil in the cooling water
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A thermostatic expansion valve is properly controlling evaporator superheat. Adjusting this valve to lower the superheat will result in a/anA.evaporator pressure decreaseB.evaporator coil over-feedC.evaporator capacity increaseD.expansion valve diaphragm rupture
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单选题If the coolant temperature of a closed cooling water system for a diesel engine gradually increases, the trouble usually is （）A
a broken shaft on the freshwater pumpB
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an incorrect thermostatic element operating rangeD
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单选题During working, thermostatic expansion valve should be （）.A
either all the way open or all the way closedB
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controlled by liquefied pressure
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单选题Which operation should be done when launching an inflatable liferaft by hand?（）A
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单选题When operating the air supply system in a covered lifeboat the（）.A
fuel supply valve should be closedB
hatches，doors，and oar ports should be closedC
air cylinder shut-off valve should be closedD
engine should be shut off
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单选题A three-way thermostatic control valve regulates the diesel engine cooling water temperature by passing a portion of the water （）.A
around the engineB
around the coolerC
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单选题A more sophisticated pressure reducing valve incorporates a pilot valve which controls the fluid above the valve operating piston in response to downstream pressureThe bold and italic word “which” means （）.A
a pressure reducing valveB
a pilot valveC
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单选题A ruptured diaphragm in a thermostatic expansion valve will cause the valve to （）.A
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closeC
remain in its positionD
flood the evaporator with refrigerant
考题
单选题What is the function of thermostatic expansion valve in a compression refrigeration system?（）A
nonexistentB
for controlling pressureC
for controlling superheatD
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单选题Many diesel engine exhaust valves are being constructed with hollow stems filled with sodium in order to （）A
provide added wear protection against today’s corrosive quality of fuelB
increase overall valve strength due to the high gas pressuresC
assist in dissipating heat due to the extreme operating temperaturesD
reduce the overall weight of the valve thus helping eliminate valve spring surge and hammering
考题
单选题Thermostatic expansion valve are （）.A
either all the way open or all the way closedB
normally openC
throttled depending on loadD
controlled by suction pressure
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单选题Diesel engine air start valve timing is controlled by（）A
engine operating speedB
an air manifoldC
a hydraulic distributorD
individual cams and valve gear
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单选题The arrangement and shape of the cams on a diesel engine camshaft directly control which of the listed groups of operating conditions?（）A
speed, torque, and horsepower productionB
firing order, valve timing, and valve liftC
fuel consumption, efficiency, and cylinder pressureD
scavenge pressure, compression ratio, and exhaust pressure
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单选题A relief valve for a cargo pump is generally installed（）.A
after the discharge valveB
between the pump and discharge valveC
after the suction valveD
between the pump and suction valve
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单选题A thermostatic expansion valve is properly controlling evaporator superheatAdjusting this valve to lower the superheat will result in a/an （）.A
evaporator pressure decreaseB
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evaporator capacity increaseD
expansion valve diaphragm rupture
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单选题A gradual decrease in the discharge pressure of an operating hydraulic pump can be caused by （）.A
the four-way control valve failing to shiftB
the bleeder valve sticking in the open positionC
cold hydraulic fluidD
a clogged air vent falter on the oil reservoir
考题
单选题A cracked diaphragm in a thermostatic expansion valve will cause the valve to （）.A
return to a neutral positionB
flood the evaporatorC
openD
close
考题
单选题The thermostatic valve has a throttling action, that is to say the valve can（）A
stop the refrigerant from flowingB
force the refrigerant to flowC
cause the refrigerant pressure to riseD
cause the refrigerant pressure to fall
考题
单选题Which of the listed statements is a characteristic of the liquid charged power element used with thermostatic expansion valves?（）A
At the designed operating temperature, the liquid refrigerant charge has changed to a vaporB
The liquid refrigerant tends to collect at the bellows or diaphragm and reduces the valve sensitivityC
The sensing bulb is empty of liquid refrigerant charge at the designed operating temperatureD
The sensing bulb is never emptied of liquid refrigerant under normal operating conditions
考题
单选题A loud clicking noise from the valve compartment of an operating diesel engine would indicate（）A
worn valve seatsB
worn main bearingC
excessive valve clearanceD
weak rocker arm springs
考题
单选题The simplest method to use for determining if a centrifugal pump is operating as designed, is to （）.A
closely observe the pump discharge temperatureB
close off the discharge valve, and watch for a rise in pressureC
momentarily close off the suction valve, and watch for a rise in pressureD
use a clamp on ammeter and compare the readings to past records
考题
单选题An interlock in the remote operating valve line stops the valve （） when the engine turning gear is engaged.A
to openB
openingC
openD
opened
考题
单选题A faulty thermostatic bypass valve, in a diesel engine cooling system, can result in （）A
excessive time required for warming-upB
excessive freshwater corrosionC
scale formation on the saltwater sideD
saltwater mixing with the freshwater
考题
单选题The major difference between the discharge and suction valves installed in most low pressure, reciprocating air compressors is that（）A
one valve seats upwards, while the other seats downwardsB
the reed valves used on the discharge are made substantially thicker and heavier than the suction valvesC
the suction valve springs exert a greater tension than the discharge valve springsD
the discharge valve springs exert a greater tension than the suction valve springs
考题
单选题The jacket water temperature in a diesel engine closed freshwater cooling system is normally controlled by （）A
regulating the level of corrosion inhibitor in the primary cooling systemB
the level of the freshwater expansion tankC
varying the engine load to meet temperature requirementsD
the operation of the thermostatic valve
考题
单选题Which of the listed devices would be installed at a control system air pressure reducing station?（）A
Moisture separatorB
Vacuum breakerC
LubricatorD
Non-return valve
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