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The amount of fuel delivered by a helical plunger fuel injection pump is controlled by ______.
A.varying the pump discharge pressure
B.varying the pump return pressure
C.rotation of the pump plunger
D.rotation of the pump barrel
参考答案
更多 “ 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 ” 相关考题
考题
The plunger in a jerk pump is rotated until the release port is uncovered If the port remains uncovered all of the time, which of the listed operations will occur?A.No fuel will be deliveredB.The maximum effective stroke will be attainedC.The fuel delivered to the cylinder will be excessiveD.The injection nozzle will overheat and carbonize
考题
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
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 amount of fluid delivered by a helical pump can be regulated by （）.A
throttling the pressure lineB
changing the speed of the rotorC
either A or BD
None of the above is tree
考题
单选题The main purpose of changing main engine to electronic controlled is not to（）A
control fuel injection time more preciselyB
control fuel injection rate more preciselyC
meet the environmental requirementsD
meet high engine speed requirements
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 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
考题
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
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
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
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The amount of fuel delivered by a unit injector is controlled by the （）A
camshaftB
main springC
rack positionD
nozzle orifice size
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The amount of fuel injection into a diesel engine cylinder by a unit injector, is controlled by（）A
the firing pressure in the cylinderB
a metering helix inside the pumpC
varying the physical length of the plunger strokeD
varying the clearance between the injector cam and the injector rocker arm
考题
单选题The amount of fuel delivered for each cycle must be in accordance with the engine load, and the same quantity of fuel must be delivered to each cylinder for each power stroke at that load.Which of the following statements describes this requirement?（）A
Proper timingB
Accurate meteringC
Suitable injection rateD
Suitable atomization rate
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
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
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