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 o

题目
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 decreased

B

quantity of fuel injected will always be increased

C

start of injection is advanced

D

duration of injection will always be greater

相似考题

1.A smoking exhaust from an operating diesel engine could be caused by( ).A.low sulfur content in the fuelB.a loose injector inlet connectionC.late fuel injectionD.high injection pressure

2.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&39; 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

3.Fuel is admitted to a diesel engine cylinder through the ______.A.injector nozzlesB.carburetorC.exhaust portsD.intake valves

4.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

更多“When the opening pressure of a diesel fuel injector is great”相关问题

  • 第1题：

    单选题
    A leaking diesel engine fuel injector will cause（）
    A

    prolonged maintenance intervals

    B

    improved atomization

    C

    greater fuel economy

    D

    incomplete combustion


    正确答案： D
    解析： 暂无解析

  • 第2题：

    单选题
    The fuel injector injects a fine spray of fuel into the hot air and combustion （）, producing much high pressure in the gases.
    A

    has begun

    B

    takes place

    C

    occurs

    D

    happens


    正确答案： D
    解析： 暂无解析

  • 第3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 decreased

    B

    Quantity of fuel injected will always be increased

    C

    Start of injection tends to be advanced

    D

    Duration of injection will always greater


    正确答案： A
    解析： 暂无解析

  • 第4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 pressure

    B

    retard the fuel injector timing to reduce power

    C

    increase the fuel rack setting

    D

    reduce the load on the engine


    正确答案： D
    解析： 暂无解析

  • 第5题：

    单选题
    Which one is not the normal operation for boiler shutdown?（）
    A

    Carry out soot blowing if permissible

    B

    Change fuel supply to diesel oil

    C

    Close steam stop valves on boiler when pressure is reduced

    D

    Drain boiler empty when it has cooled down


    正确答案： B
    解析： 暂无解析

  • 第6题：

    单选题
    A change in the quality of fuel atomization by a diesel engine fuel injector would be caused by a/an （）
    A

    increase in engine speed

    B

    increase in cylinder turbulence

    C

    leaking needle valve

    D

    reduction in cylinder turbulence


    正确答案： C
    解析： 暂无解析

  • 第7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 cylinder

    B

    a metering helix inside the pump

    C

    varying the physical length of the plunger stroke

    D

    varying the clearance between the injector cam and the injector rocker arm


    正确答案： A
    解析： 暂无解析

  • 第8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 injection

    B

    allow oil backflow from the injector to the helix

    C

    reduce fuel oil pressure between injection strokes

    D

    meter the quantity of fuel delivered


    正确答案： C
    解析： 暂无解析

  • 第9题：

    单选题
    A distorted spray pattern from a fuel injector can cause a diesel engine to have （）
    A

    higher firing pressure

    B

    more power output

    C

    lower fuel pressure

    D

    less power output


    正确答案： B
    解析： 暂无解析

  • 第10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 pressure

    B

    reduce fuel booster pump pressure

    C

    adjust the fuel rack

    D

    retard fuel injector timing


    正确答案： B
    解析： 暂无解析

  • 第11题：

    单选题
    If you suspect a diesel engine is misfiring due to air leakage into the fuel system, you should begin looking for the leak at the （）
    A

    fuel line connections to cylinder injection valves

    B

    gasket surfaces of the fuel oil filters

    C

    discharge fitting of the fuel injector pumps

    D

    suction side of the fuel oil tran


    正确答案： D
    解析： 暂无解析

  • 第12题：

    单选题
    The minimum fuel oil delivery pressure required for diesel engine injection depends primarily on the（）
    A

    degree of cylinder air turbulence

    B

    firing pressure in the engine

    C

    quality of fuel to be injected

    D

    duration of the ignition delay period


    正确答案： A
    解析： 暂无解析

  • 第13题：

    单选题
    A sudden drop in diesel engine cylinder compression pressure can be caused by（）
    A

    a leaking fuel injector nozzle

    B

    a clogged air filter

    C

    excessively early fuel injection

    D

    malfunctioning valves


    正确答案： A
    解析： 暂无解析

  • 第14题：

    单选题
    A practical way of checking for excessive fuel injection in one cylinder of an operating diesel engine is to （）
    A

    feel the high pressure fuel line

    B

    check the cylinder exhausts for white smoke frequently

    C

    check the cylinder exhaust temperature

    D

    isolate each cylinder and inspect the injector


    正确答案： A
    解析： 暂无解析

  • 第15题：

    单选题
    A smoking exhaust from an operating diesel engine could be caused by （）
    A

    low sulfur content in the fuel

    B

    a loose injector inlet connection

    C

    late fuel injection

    D

    high injection pressure


    正确答案： A
    解析： 暂无解析

  • 第16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 valve

    B

    nozzles

    C

    piston

    D

    spring


    正确答案： A
    解析： 暂无解析

  • 第17题：

    单选题
    If a diesel engine is smoking excessively under load, the cause could be （）
    A

    low exhaust back pressure

    B

    early fuel injection in one of the cylinders

    C

    compression pressure in one of the cylinders

    D

    plugged injector holes


    正确答案： C
    解析： 暂无解析

  • 第18题：

    单选题
    Injection lag in a diesel engine may be caused by（）
    A

    a higher cetane number of fuel oil

    B

    the diesel fuel used having a high viscosity

    C

    mechanical rigidity in the lube pump mechanism

    D

    a decrease rigidity in the fuel pump delivery pressure


    正确答案： C
    解析： 暂无解析

  • 第19题：

    单选题
    A fuel injection valve opening at pressure lower than normal will result in（）.
    A

    late fuel injection

    B

    early fuel injection

    C

    high exhaust temperature from that cylinder

    D

    decreased effective stroke from that injector


    正确答案： B
    解析： 暂无解析

  • 第20题：

    单选题
    Indirect cooling of fuel injector nozzle holders for diesel engines is accomplished primarily by （）.
    A

    heat conduction into the injected fuel oil

    B

    heat conduction into the water jacket wall

    C

    water circulation through passages in the holder

    D

    fuel oil circulation through passages in the holder


    正确答案： B
    解析： 暂无解析

  • 第21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 leaking

    B

    excessive mechanical clearance between the piston crown and cylinder head

    C

    excessively worn fuel pump plunger

    D

    excessive exhaust back pressure


    正确答案： A
    解析： 暂无解析

  • 第22题：

    单选题
    A sudden drop in compression pressure in one cylinder of a diesel engine can be caused by（）
    A

    a leaking fuel injector nozzle

    B

    a clogged air filter

    C

    excessively early fuel injection

    D

    malfunctioning valves


    正确答案： D
    解析： 暂无解析

  • 第23题：

    单选题
    When comparing different fuels for different engines, the ignition quality of diesel fuel oils becomes a less critical consideration as （）
    A

    the amount of lube oil additives increase

    B

    piston speeds increase

    C

    injection pressure decrease

    D

    engine speeds decrease


    正确答案： D
    解析： 暂无解析

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