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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
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更多 “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 the piston skirt” 相关考题
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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
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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
考题
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.
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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
考题
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
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若包装箱上标示下图标志是指（）。A、keep away from moistureB、keep away from heatC、keep away from coldD、keep away from fire
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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.
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单选题（）can be used to prevent hydraulic system overloaded or keep the pressure of oil outlet from pump constant.A
Overflow valveB
Reducing valveC
Balancing valveD
Reducing valve or balancing valve
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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 tankB
Set out drip pans and sawdust and begin to mop up the spillC
Signal the shore control point to shutdownD
Close the valve on the tank vent line
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单选题Fuel oil is regularly transferred to the day tank in order to （）A
allow impurities to settle out of the fuelB
allow air to escape from the fuelC
make fuel available for immediate useD
all of the above
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单选题Most hydraulic steering gears are fitted with relief valves which（）A
function when the rudder is amidshipsB
relieve excess whip pressure from the hydraulic oil systemC
protect the piping assembly from external rudder shockD
relieve excessive telemotor pressure
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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 fuelB
insufficient fuel for combustionC
clogged air intake passagesD
burning lubricating oil
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单选题In a diesel engine, exhaust valves open before the intake ports are uncovered to （） Ⅰ.reduce pumping losses Ⅱ.reduce back pressureA
ⅠonlyB
ⅡonlyC
bothⅠand ⅡD
neitherⅠnor Ⅱ
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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 cycleB
admit water to the dry pipeC
throttle the forced draft fan output for proper combustionD
reduce excess steam pressure in the boiler
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单选题The viscosity regulator controls the fuel oil temperature （） provide oil at the correct viscosity for combustion.A
in order thatB
because ofC
in order toD
owing to
考题
单选题Diesel engine fuel oil contamination often results in （）A
governor malfunctionsB
fuel injection system malfunctionsC
high cylinder lube oil temperaturesD
low intake temperatures
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单选题The auctioneer may decide to sell the “lots” out of the order because _____.A
he sometimes wants to confuse the buyersB
he knows from experience that certain people will want to buy certain itemsC
he wants to keep certain people waitingD
he wants to reduce the number of buyers
考题
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 purifierB
Fuel oil discharging from the water outlet of the lube oil purifierC
Lube oil discharging from the water outlet of the lube oil purifierD
A change in the lube oil viscosity
考题
单选题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
考题
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 filmB
maintain an oil film on the lower liner where scuffing is prevalentC
keep excess oil away from intake and exhaust portsD
help cushion piston skirt side thrust by providing a hydrodynamic oil wedge
考题
单选题Broken intake valve springs on one cylinder of a diesel engine can cause the engine to （）A
Over speedB
fire improperlyC
lose oil pressureD
overheatrapidly
考题
单选题Directional intake ports in diesel engines are used to （）.A
reduce air charge turbulenceB
induce air swirlC
deflect hot combustion gas away from the valvesD
oppose the effects of piston induced squish
考题
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 screwsB
completely around the vesselC
to leeward of the vesselD
to windward of the vessel
考题
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 edgesB
on both the external top and bottom edgesC
on both the external and internal bottom edgesD
on all the four edges
考题
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 removedB
fuel oil transfer pumps cannot tolerate small amounts of dirt in the oilC
fuel injectors may be damaged by foreign particles in the fuel oilD
dirty fuel will clog the intake air filter
考题
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 gasesB
energy supplied to the turbochargerC
air pressure to the intake manifoldD
purge of exhausted gases from the cylinders
考题
单选题The intake ports of a two-strike/cycle diesel engine are opened and closed by the action of the （）A
camshaftB
piston movementC
exhaust valvesD
vertical drive
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