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单选题
As the plunger moves up, the ports are closed and the fuel （） and delivered to the injector nozzle at very high pressure.
A
being compressed
B
to be pumped up
C
is pressurized
D
are built up
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As the plunger moves upwards in the barrel, injection will commence once the plunger bas_______the spill ports and the pressure builds up.A.opened upB.closed offC.lined upD.taken off
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An increase in the fuel injection pump discharge pressure can be caused by a/an _______.A.leaking delivery valveB.excessive bearing end playC.plugged injector spray holeD.increased plunger stroke
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考题
The amount of fuel delivered by a helical plunger fuel injection pump is controlled by ______.A.varying the pump discharge pressureB.varying the pump return pressureC.rotation of the pump plungerD.rotation of the pump barrel
考题
To ensure proper seating when closing a valve on a tank，the valve should be ______．A.Set up as tight as possible by handB.Set up tight using a valve wrenchC.Closed，opened a half turn，and then closedD.Closed against the stop and the locking pin inserted
考题
单选题In a jerk pump, the amount of fuel that will be forced through the spray nozzle on each upward stroke of the plunger depends on （）A
the pump supply pressureB
the slope of the fuel camC
how the plunger is rotatedD
the number of sleeve segments engaged with the rack
考题
单选题Movement of the pump control rack in a fuel injection system using individual plunger-type pumps （）A
changes the position of the fuel inlet portsB
changes the length of the pump strokeC
varies the quantity of fuel deliveredD
varies the compression of the delivery valve spring
考题
单选题The plunger in the fuel injector pump, usually operated by a （）, is driven up and down when working.A
crankshaftB
camshaftC
piston rodD
rack and pinion
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单选题A common trouble with the fuel pump plunger or fuel valve spindle is （）.A
water leakageB
steam leakageC
oil leakageD
air leakage
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单选题The percentage of impurities in a specific fuel oil sample is determined by （）.A
settling in a fuel tankB
testing in a laboratory centrifugeC
burning in a calorimeterD
testing in a closed cup
考题
单选题Diesel engine injection lag is caused by（）A
compressibility of the fuelB
high fuel oil supply flowC
scored plunger and barrel packingD
excessive air turbulence
考题
单选题The fuel injector pump is operated by （） which drives the plunger up and down.A
a separate motorB
a camC
a generatorD
a chain
考题
单选题In a unit injector the amount of fuel that will be forced through the spray nozzle on each stroke of the plunger depends on （）A
the pump supply pressureB
the slope of the fuel camC
how the plunger is rotatedD
the number of sleeve segments engaged with the rack
考题
单选题It is important to note that the injection only takes place when the plunger is moving up the cam （）.A
base circleB
slopeC
bottom pointD
top point
考题
单选题A tug may be in danger of tripping when（）.A
towed sideways by an overwhelming force on the towlineB
her tow moves parallel to and forward on either side of the tugC
the tow is no longer directly astern but moves up on her quarterD
All of the above
考题
单选题Differential needle valves used in fuel injectors are directly closed by（）A
cam actionB
spring forceC
fuel oil pressureD
firing pressure
考题
单选题The fuel is supplied to the pump through ports or openings in the （） or cylinder of the pump.A
bottleB
injectorC
pistonD
barrel
考题
单选题The effective pump stroke of an individual port-and-helix fuel injection pump is determined by the （）A
fuel delivery pressureB
pump plunger diameterC
plunger control rack positionD
total pump stroke
考题
单选题Faulty operation of diesel engine fuel injection nozzles can be directly caused by （）.A
water in the fuel oil supplyB
excessive fuel nozzle holder coolingC
a distorted fuel spray patternD
leakage past the plunger into the oil drain
考题
单选题An increase in the fuel injection pump discharge pressure can be caused by a/an （）A
leaking delivery valveB
excessive bearing end playC
plugged injector spray holeD
increased plunger stroke
考题
单选题Cocks and valves control or interrupt flow, and have internal passages arranged so that they can be restricted or closed: in cocks, by rotating the plug, and in valves, by lowering, raising or rotating a disc in relation to a seating surfaceAccording to the above sentence, which of the following statements is not true?（）A
Flows of fluids can be restricted by both cocks and valvesB
There are seats in the internal passages of valvesC
A disc of valve only moves up and downD
We can infer that there is a bore in cock ping
考题
单选题Because of the close tolerances used in diesel engine fuel oil pumps, a worn plunger requires（）A
grinding the spare plunger to the barrelB
replacing the plunger and the barrelC
highly polishing both the plunger and barrelD
replacing plunger only
考题
单选题As the plunger moves upwards in the barrel, injection will commence once the plunger has （） the spill ports and the pressure builds up.A
opened upB
closed offC
lined upD
taken off
考题
单选题If the plunger or barrel of a fuel injection jerk pump becomes damaged,（）A
only the replacement of the entire pump would be acceptableB
the injection pump and injection nozzle must be replacedC
either the barrel or plunger must be replacedD
the barrel and plunger must be replaced as a unit
考题
单选题The amount of fuel delivered by a helical plunger fuel injection pump is controlled by （）A
varying the pump discharge pressureB
varying the pump return pressureC
rotation of the pump plungerD
rotation of the pump barrel
考题
单选题The intake ports of a two-strike/cycle diesel engine are opened and closed by the action of the （）A
camshaftB
piston movementC
exhaust valvesD
vertical drive
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