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单选题
The fuel injector pump is operated by （） which drives the plunger up and down.
A
a separate motor
B
a cam
C
a generator
D
a chain
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If you suspect a diesel engine is misfiring due to air leakage into the fuel system, you should begin looking for the leak at theA.fuel line connections to the cylinder injection valvesB.gasket surfaces of the fuel oil filtersC.discharge fittings of the fuel injector pumpsD.suction side of the fuel oil transfer pump
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Which of the following problems is the main source of fuel pump and injection system malfunctions?A.Improper lubricationB.Air in the fuel systemC.Coated fuel linesD.Excessive vibration
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第一组Older loop scavenged engines may have a single injector mounted centrally in the cylinder head. Because the exhaust valve is in the center of the cylinder head on modern uniflow scavenged engines the fuel valves (2 or 3) are arranged around the periphery of the head. The pressure at which the injector operates can be adjusted by adjusting the loading on the spring. The pressures at which the injectors operate vary depending on the engine, but can be as high as 540 bar. Some injectors have internal cooling passages in them extending into the nozzle through which cooling water is circulated. This is to prevent overheating and burning of the nozzle tip. Injectors on modern engines do not have internal cooling passages. They are cooled by a combination of the intensive bore cooling in the cylinder head being close to the valve pockets and by the fuel which is re-circulated through the injector when the follower is on the base of the cam or when the engine is stopped. As well as cooling the injector, re-circulating the fuel when the engine is stopped keeps the fuel at the correct viscosity for injection by preventing it from cooling down. Fuel injectors must be kept in good condition to maintain optimum efficiency, and to prevent conditions arising which could lead to damage within the cylinder. Injectors should be changed in line with manufacturers recommendations, overhauled and tested. Springs can weaken with repeated operation leading to the injector opening at a lower pressure than designed. The needle valve and seat can wear which together with worn nozzle holes will lead to incorrect atomization and dribbling.Modern uniflow scavenged engines have______.A.a single injector mounted in the center of the cylinder headB.several injectors mounted around the external boundary of the cylinder headC.a single injector mounted at the external boundary of the cylinder headD.several injectors mounted in the center of the cylinder head
考题
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
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 injector pump is operated by a cam which drives （） up and down.A
the needle valveB
the plungerC
the pistonD
the cylinder
考题
单选题The injector pump is operated by a cam which drives the plunger （）.A
top and bottomB
to and froC
up and downD
back and forth
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
考题
单选题Load control on a diesel engine is accomplished by （）.A
regulating the speed of the turbochargerB
rotating the fuel injector pump plungerC
regulating the speed of the fuel oil transfer pumpD
changing engine timing
考题
单选题Which of the following problems is the main source of fuel pump and injection system malfunctions?（）A
Improper lubricationB
Air in the fuel systemC
Coated fuel linesD
Excessive vibration
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单选题When the opening pressure of a diesel engine fuel injector is greater than that specified by the engine manufacturer, which of the following problems can be expected?（）A
Quantity of fuel injected tends to be decreasedB
Quantity of fuel injected will always be increasedC
Start of injection tends to be advancedD
Duration of injection will always greater
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单选题Which of the following is operated from the main engine room console on an automated vessel?（）A
Fire pump and lube oil pumpB
Lube oil pump and distilling plantC
Distilling plant and shaft alley doorD
Shaft alley door and fixed CO2 release
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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
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单选题A fuel leak occurs in the high pressure fuel piping between the injection pump and fuel nozzleThis requires immediate repair because of the （）A
high cost of fuelB
serious fire hazardC
possibility of pollutionD
poor combustion which will occur in that cylinder
考题
单选题The pump has a constant stroke and the amount of fuel delivered is regulated by rotating （） which has a specially arranged helical groove cut into it.A
the pump cylinderB
the pump camC
the pump plungerD
the pump miler
考题
单选题To successfully reduce an excessively high diesel engine exhaust gas temperature, you should （）.A
reduce the engine driven fuel pump outlet pressureB
retard the fuel injector timing to reduce powerC
increase the fuel rack settingD
reduce the load on the engine
考题
单选题The needle valve in the injector （） at a pre-set pressure which ensures that the fuel will atomize once it enters the cylinder.A
will liftB
will be liftedC
will closeD
will be closed
考题
单选题The （） in the injector will lift at a pre-set pressure which ensures that the fuel will atomize once it enters the cylinder.A
needle valveB
nozzlesC
pistonD
spring
考题
单选题The injector pump is operated by a cam which drives the （） up and down.A
pistonB
drumC
plungerD
barrel
考题
单选题The purpose of the delivery check valve used in a diesel fuel injection jerk pump is to （）.A
assist in a quick cutoff of fuel injectionB
allow oil backflow from the injector to the helixC
reduce fuel oil pressure between injection strokesD
meter the quantity of fuel delivered
考题
单选题One remedy for a high firing pressure, in addition to a high exhaust temperature in one cylinder of a diesel engine, is to （）A
increase scavenge air pressureB
reduce fuel booster pump pressureC
adjust the fuel rackD
retard fuel injector timing
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There is an injection pump for each cylinder, which is usually operated once every cycle by （） on the camshaft.A
a gearB
a camC
a rodD
a miler
考题
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
考题
单选题Which portable fire extinguisher is normally recharged in a shore facility?（）A
Dry chemical (cartridge-operated)B
Water (cartridge-operated)C
Water (pump tank)D
Carbon dioxide
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
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