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单选题
An increase in the fuel injection pump discharge pressure can be caused by a/an （）
A
leaking delivery valve
B
excessive bearing end play
C
plugged injector spray hole
D
increased plunger stroke
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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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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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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When the opening pressure of a diesel fuel injector is greater than that specified by the engine manufacturer，the （）A
quantity of fuel injected is decreasedB
quantity of fuel injected will always be increasedC
start of injection is advancedD
duration of injection will always be greater
考题
单选题The primary function of a fuel delivery check valve assembly is to（）A
deliver proper fuel quantity to the injection nozzleB
provide rapid fuel injection cutoffC
control fuel quantity entering the pump bodyD
control fuel pressure delivered to the combustion chamber
考题
单选题Problems with the diesel engine fuel injection pump are usually caused by（）A
improper adjustmentB
contaminated fuelC
kinked fuel linesD
excessive engine vibration
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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
考题
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
考题
单选题If the viscosity of the liquid being transferred remains constant as the discharge pressure increases, the rotary pump （）.A
capacity will increaseB
capacity will decreaseC
suction pressure will increaseD
suction pressure will decrease
考题
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 usual symptoms of cavitation in a centrifugal pump is （）.A
noise and vibrationB
an increase in discharge pressureC
an increase in suction pressureD
lifting of the relief valve
考题
单选题Injection lag in a diesel engine may be caused by（）A
a higher cetane number of fuel oilB
the diesel fuel used having a high viscosityC
mechanical rigidity in the lube pump mechanismD
a decrease rigidity in the fuel pump delivery pressure
考题
单选题Which of the following problems may occur if the opening pressure of a fuel injection nozzle is greater than specified by the engine manufacturer?（）A
The amount of fuel injected will be increasedB
The start of injection will be retardedC
The nozzle will permit fuel to dribbleD
The spray pattern will be distorted
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The major cause of fuel pump and injection system problems is （）A
improper adjustmentsB
contaminated fuelC
kinked fuel linesD
excessive engine vibration
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单选题The pump discharge pressure will be considerably higher than the pressure at the （）.A
pump entry branchB
outlet pipeC
impellerD
None of the above is true
考题
单选题An increase in rotor clearances in a rotary pump will （）.A
increase discharge pressureB
decrease pump capacityC
decrease pump cavitationD
decrease reaction ring clearance
考题
单选题Low compression pressure in a diesel engine may be the result of （）A
insufficient fuel supply due to fuel pump valves sticking or leakingB
excessive mechanical clearance between the piston crown and cylinder headC
excessively worn fuel pump plungerD
excessive exhaust back pressure
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The major cause of problems occurring with fuel injection equipment is（）A
incorrect replacement of barrels and plungers of jerk pumpsB
overheating of the nozzle orificesC
cracked pump housingsD
dirt in the fuel
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 minimum fuel oil delivery pressure required for diesel engine injection depends primarily on the（）A
degree of cylinder air turbulenceB
firing pressure in the engineC
quality of fuel to be injectedD
duration of the ignition delay period
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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