单选题In order to keep excess oil from the intake ports in two-stroke/cycle diesel engines, （）A wide compression rings are usedB oil rings are located above the pistonC chromium plating is used on all piston ringsD oil rings are located near the bottom of th

题目
单选题
In order to keep excess oil from the intake ports in two-stroke/cycle diesel engines, （）
A

wide compression rings are used

B

oil rings are located above the piston

C

chromium plating is used on all piston rings

D

oil rings are located near the bottom of the piston skirt

相似考题

1.We can draw a conclusion from the text that______.A) oil-price shocks are less shocking nowB) inflation seems irrelevant to oil -price shocksC) energy conservation can keep down the oil pricesD) the price rise of crude leads to the shrinking of heavy industry

2.We can draw a conclusion from the text thatA oil-price shocks are less shocking now.B inflation seems irrelevant to oil-price shocks.C energy conservation can keep down the oil prices.D the price rise of crude leads to the shrinking of heavy industry.

3.What would white exhaust smoke from a diesel engine probably mean ________．A.Late fuel injectionB.Excess combustion airC.Dribbling injector tipsD.Excessive lube oil consumption

4.第二组Displacement pumps are those where the volume of the pump chamber is alternately increased to draw the liquid in from the suction pipe and then decreased to force the liquid out into the delivery pipe. Centrifugal pumps are those wherein an impeller rotating at high speed throws the liquid by centrifugal force from the center to the periphery of the impeller where the liquid is discharged through the delivery outlet.Gear pump consists of two or more meshing gears (spur, single or double helical teeth) enclosed m a close-fitted housing. These are used extensively for pumping fuel oil, lubricating oil and hydraulic oil. When gears are unmeshed on the inlet side, a pressure drop occurs that helps the atmospheric pressure acting on the surface of the oil in the reservoir to force it up the pipe to fill the void, the oil is then transferred around the periphery of the pump housing. As the gear teeth mesh again on the outlet side, they form. a seal that prevents oil from backing up to the inlet, the oil in the void is then be forced out into the discharge line.All vane pumps have a rotor driven within a ring (cam ring) by a drive shaft coupled to a prime mover. A cylindrical rotor with sliding vanes, generally in radial slots, rotates within the ring. The center of the rotor is offset from the center of the ring. In a simple vane pump, as the rotor turns, the vanes are forced outward against the inner surface of the cam ring by centrifugal force. This outward radial movement of the vanes and turning of the rotor causes the chamber between the vanes to increase as the vanes pass further away from the inlet port. This increase in volume results in a lowering of pressure until the atmospheric pressure is sufficient to force oil from the reservoir into the inlet chamber. Oil from the inlet is swept away by the vanes toward the outlet port through a decreasing series of chambers until it is forced through the outlet port. A vane pump of balanced design has an elliptical cam ring so that two pumping chambers are formed. This pump is in hydraulically balance, since the two intake and two outlet ports are diametrically opposed to each other. Therefore the side loads exerted on the rotor cancel out, thereby increasing bearing lift and permitting high operating pressure.According to the last sentence of paragraph 1, from where the liquid is discharged through the delivery outlet?A.from the eye of the impellerB.from passage of impellerC.from the periphery of the impellerD.from the impeller

更多“In order to keep excess oil from the intake ports in two-str”相关问题

  • 第1题：

    The Norwegian Government has tried to ______.

    A. encourage the oil companies to discover new oil sources
    B. prevent oil companies employing people from northern Norway
    C. help the oil companies solve many of their problems
    D. keep the oil industry to something near its present size

    答案：D
    解析：
    通过文章第一段容易排除A、B、C项，本题正确答案为D。

  • 第2题：

    When configuring unified ports on a 5548 switch， which port ordering must be respected？（）

    • A、 Fibre Channel ports must be configured from the first port in the module.
    • B、 Ethernet ports must be configured from the last port in the module.
    • C、 Fibre Channel ports must be configured from the last port in the module.
    • D、 Ethernet ports must be configured from the first port in the module.

    正确答案:C,D

  • 第3题：

    单选题
    Your vessel is taking on bunkers from a shore side facility, if oil begins flowing from one tank vent, which of the following actions should be taken FIRST?（）
    A

    Open the intake valve to an adjacent tank

    B

    Set out drip pans and sawdust and begin to mop up the spill

    C

    Signal the shore control point to shutdown

    D

    Close the valve on the tank vent line


    正确答案： C
    解析： 暂无解析

  • 第4题：

    单选题
    Most hydraulic steering gears are fitted with relief valves which（）
    A

    function when the rudder is amidships

    B

    relieve excess whip pressure from the hydraulic oil system

    C

    protect the piping assembly from external rudder shock

    D

    relieve excessive telemotor pressure


    正确答案： C
    解析： 暂无解析

  • 第5题：

    单选题
    In a diesel engine, exhaust valves open before the intake ports are uncovered to （） Ⅰ.reduce pumping losses Ⅱ.reduce back pressure
    A

    Ⅰonly

    B

    Ⅱonly

    C

    bothⅠand Ⅱ

    D

    neitherⅠnor Ⅱ


    正确答案： B
    解析： 暂无解析

  • 第6题：

    单选题
    The viscosity regulator controls the fuel oil temperature （） provide oil at the correct viscosity for combustion.
    A

    in order that

    B

    because of

    C

    in order to

    D

    owing to


    正确答案： A
    解析： 暂无解析

  • 第7题：

    单选题
    The auctioneer may decide to sell the “lots” out of the order because _____.
    A

    he sometimes wants to confuse the buyers

    B

    he knows from experience that certain people will want to buy certain items

    C

    he wants to keep certain people waiting

    D

    he wants to reduce the number of buyers


    正确答案： C
    解析：
    由文章第三段中：he may wait until he registers the fact that certain dealers are in the room and then produce the lots they are likely to be interested in，拍卖商不按常规拍卖，是为了确定准买家的情况，推测他们可能喜欢的东西，再决定拍卖。B选项符合题意。

  • 第8题：

    单选题
    We can draw a conclusion from the text that ______.
    A

    oil-price shocks are less shocking now

    B

    inflation seems irrelevant to oil-price shocks

    C

    energy conservation can keep down the oil prices

    D

    the price rise of crude leads to the shrinking of heavy industry


    正确答案： C
    解析：
    综合理解题。文章的主要内容着重于与20世纪70年代相比，现今的石油价格波动情况及其影响。从第三段开头阐明：“there are good reasons to expect the economic consequences now to be less severe than in the 1970s”，说明现今的情况没有70年代那么严重，也就是说现今的石油价格波动不会像以前那样对经济带来如此重大的影响。第四段开头进一步阐述到“Rich economies are also less dependent on oil than they were, and so less sensitive to swings in the oil price”，即石油价格波动已经没有以前那么激烈了。

  • 第9题：

    单选题
    Broken intake valve springs on one cylinder of a diesel engine can cause the engine to （）
    A

    Over speed

    B

    fire improperly

    C

    lose oil pressure

    D

    overheatrapidly


    正确答案： D
    解析： 暂无解析

  • 第10题：

    单选题
    In order to benefit from the use of storm oil in heavy seas，the storm oil should be spread （）.
    A

    around the rudder and screws

    B

    completely around the vessel

    C

    to leeward of the vessel

    D

    to windward of the vessel


    正确答案： C
    解析： 暂无解析

  • 第11题：

    单选题
    Proper filtering and straining of fuel oil is important because the （）.
    A

    fuel oil pump will over-speed if dirt is not removed

    B

    fuel oil transfer pumps cannot tolerate small amounts of dirt in the oil

    C

    fuel injectors may be damaged by foreign particles in the fuel oil

    D

    dirty fuel will clog the intake air filter


    正确答案： A
    解析： 暂无解析

  • 第12题：

    单选题
    The intake ports of a two-strike/cycle diesel engine are opened and closed by the action of the （）
    A

    camshaft

    B

    piston movement

    C

    exhaust valves

    D

    vertical drive


    正确答案： C
    解析： 暂无解析

  • 第13题：

    若包装箱上标示下图标志是指（）。

    • A、keep away from moisture
    • B、keep away from heat
    • C、keep away from cold
    • D、keep away from fire

    正确答案:B

  • 第14题：

    单选题
    （）can be used to prevent hydraulic system overloaded or keep the pressure of oil outlet from pump constant.
    A

    Overflow valve

    B

    Reducing valve

    C

    Balancing valve

    D

    Reducing valve or balancing valve


    正确答案： D
    解析： 暂无解析

  • 第15题：

    单选题
    Fuel oil is regularly transferred to the day tank in order to （）
    A

    allow impurities to settle out of the fuel

    B

    allow air to escape from the fuel

    C

    make fuel available for immediate use

    D

    all of the above


    正确答案： C
    解析： 暂无解析

  • 第16题：

    单选题
    Black smoke exhausting from an operating diesel engine is an indication of poor combustion which may be caused by （）
    A

    water in the fuel

    B

    insufficient fuel for combustion

    C

    clogged air intake passages

    D

    burning lubricating oil


    正确答案： B
    解析： 暂无解析

  • 第17题：

    单选题
    The purpose of the safety relief valves installed on an auxiliary boiler is to （）.
    A

    relieve excess fuel oil pressure during the “off” fire cycle

    B

    admit water to the dry pipe

    C

    throttle the forced draft fan output for proper combustion

    D

    reduce excess steam pressure in the boiler


    正确答案： C
    解析： 暂无解析

  • 第18题：

    单选题
    Diesel engine fuel oil contamination often results in （）
    A

    governor malfunctions

    B

    fuel injection system malfunctions

    C

    high cylinder lube oil temperatures

    D

    low intake temperatures


    正确答案： C
    解析： 暂无解析

  • 第19题：

    单选题
    Which of the following conditions indicates the dilution of diesel engine lube oil by fuel oil?（）
    A

    Water discharging from the water outlet of the lube oil purifier

    B

    Fuel oil discharging from the water outlet of the lube oil purifier

    C

    Lube oil discharging from the water outlet of the lube oil purifier

    D

    A change in the lube oil viscosity


    正确答案： C
    解析： 暂无解析

  • 第20题：

    单选题
    Oil control rings used in two-stroke/cycle diesel engines are located near the bottom of the piston skirt in order to （）
    A

    increase the liner area covered by the oil film

    B

    maintain an oil film on the lower liner where scuffing is prevalent

    C

    keep excess oil away from intake and exhaust ports

    D

    help cushion piston skirt side thrust by providing a hydrodynamic oil wedge


    正确答案： C
    解析： 暂无解析

  • 第21题：

    单选题
    Directional intake ports in diesel engines are used to （）.
    A

    reduce air charge turbulence

    B

    induce air swirl

    C

    deflect hot combustion gas away from the valves

    D

    oppose the effects of piston induced squish


    正确答案： B
    解析： 暂无解析

  • 第22题：

    单选题
    In order to keep the oil film on the cylinder liner during the running-in period, the piston rings are slightly rounded（）
    A

    on both the external and internal top edges

    B

    on both the external top and bottom edges

    C

    on both the external and internal bottom edges

    D

    on all the four edges


    正确答案： B
    解析： 暂无解析

  • 第23题：

    单选题
    A turbocharged, four-stroke/cycle diesel engine has a larger valve overlap than a naturally aspirated four-stroke/cycle diesel engine, in order to in crease the （）.
    A

    temperature of the exhaust gases

    B

    energy supplied to the turbocharger

    C

    air pressure to the intake manifold

    D

    purge of exhausted gases from the cylinders


    正确答案： C
    解析： 暂无解析

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