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单选题
When would the available energy of the exhaust gases of a two-stroke/cycle diesel engine be insufficient to drive an exhaust gas turbocharger, resulting in the incorrect amount of air for combustion?（）
A
During operation at low speed
B
During operation at rated speed, but low power output
C
During acceleration
D
All of the above
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更多 “单选题When would the available energy of the exhaust gases of a two-stroke/cycle diesel engine be insufficient to drive an exhaust gas turbocharger, resulting in the incorrect amount of air for combustion?（）A During operation at low speedB During operation at rated speed, but low power outputC During accelerationD All of the above” 相关考题
考题
A greenhouse is a building made of glass which is used for keeping plants when the outside temperature is low. In a similar way there are several gases in the atmosphere which trap(捕捉)the heat produced by the sun and prevent it from escaping. These gases are known as"greenhouse gases"，and the way in which they trap heat in the atmosphere is called the "greenhouse effect". This is not simply air pollution. Most of the main greenhouse gases exist naturally in small amounts in our atmosphere, and without them earth would be 30 degrees colder and human life would not exist. In other words, the greenhouse effect is a natural course which is to some degree helpful to us.The problem is that in the last century and a half, we have been putting too many of these gases into the earth's atmosphere by burning large quantities of coal and oil and by cutting down forests. The rapid increase in greenhouse gases is making the world warmer. The world's temperature has already gone up by half a degree this century, and the sea level has risen by 10 centimetres. If the amount of carbon dioxide(二氧化碳)in the atmosphere doubles, there will probably be a rise in the earth's temperature of between 1 and 4 degrees. This may seem a small increase, but it would be enough to cause major changes in geography and agriculture. Large areas of the world would be flooded, and some areas would become dry and unable to produce crops. It is important, too, to consider that there may be a delay of about 30 years in the greenhouse effect. This means that we are probably experiencing only now the effect of the gases put into the atmosphere before the 1960s. Since then, our use of these gases has greatly increased.1. The"greenhouse effect"means _____.A. the way in which gases are used for keeping plants warmB. a natural course which is some degree helpful to usC. the way"greenhouse gases"trap heat on the earthD. the whole course in which greenhouse gases prevent heat2. If there were no greenhouse effect, _____.A. no plants would grow on our planetB. earth would be thirty degrees colderC. man could not live on the earthD. All of the above answers are correct3. Which of the following is NOT true? _____A. Burning too much coal and oil produces lots of greenhouse gases.B. It has become warmer on the earth now than in the past.C. Gases put into the atmosphere now will affect the earth years later.D. The temperature in a greenhouse is as high as that in the atmosphere.4. Suppose the earth's temperature rose by 3 degrees, _____.A. great harm would be done to mankindB. the sea level would go by 10 centimetresC. all the land in the world would be floodedD. crops would be unable to grow on the earth5. This passage mainly deals with _____.A. the concept(概念)and harm of greenhouse effectB. the relation between greenhouse gases and manC. the concept and change of greenhouse effectD. the effect of the rise of the earth's temperature
考题
In a()boiler the hot gases from the furnace pass gases from the furnace pass water is on the outside.
A.water-tubeB.fire-tubeC.exhaust gasD.composite
考题
A two stroke diesel engine exhaust temperature will be lower than a four stroke diesel engine of the same displacement because the _____. ① MEP is lower and the scavenging air is cooling the exhaust gases ② valve overlap in a four strokeA.①B.②C.① and ②D.Neither ① nor ② is correct
考题
Which of the following utilities would be used to configure energy saving measures when a laptop switches to battery power?()
A.MSTSCB.ACPIC.GDID.MSCONFIG
考题
In a ______boiler the hot gases from the furnace pass through the tubes while the water is on the outside.A.water-tubeB.fire-tubeC.exhaust gasD.Composite
考题
Which of the following utilities would be used to configure energy saving measures when a laptop switches to battery power?（）A、MSTSCB、ACPIC、GDID、MSCONFIG
考题
单选题Exhaust gases are generally removed from the cylinders of a two-stroke/cycle diesel engine by（）A
natural aspirationB
masked intake valvesC
air cellsD
scavenging air
考题
单选题（） is the removal of exhaust gases by blowing in fresh air.A
Gas exchangeB
ChargingC
ScavengingD
Supercharging
考题
单选题The exhaust system of a diesel engine is usually designed to remove exhaust gases and to （）A
provide exhaust back pressureB
prevent exhaust smoke emissionsC
power a reciprocating superchargerD
muffle exhaust gas noise
考题
单选题Which of the following gases represents the greatest threat to personnel safety in an engine room where the exhaust is leaking from a diesel engine?（）A
Carbon dioxideB
Carbon monoxideC
Carbon trioxideD
Hydrogen sulfide
考题
单选题Forcing the exhaust gases form the cylinder of an operating diesel engine with the aid of a blower is known as （）A
scavengingB
forced draftC
turbo-chargingD
aspiration
考题
单选题The exhaust system for a turbocharged two-stroke/cycle diesel engine functions to（）A
discharge exhaust gases and smokeB
furnish energy to the turbochargerC
reduce engine room noiseD
all of the above
考题
单选题Trunk type diesel engine pistons are effectively cooled when heat is（）A
radiated through the engine blockB
transferred to water cooled cylinder wallsC
conducted through the piston crownD
transferred to escaping exhaust gases
考题
单选题When would the available energy of the exhaust gases of a two-stroke/cycle diesel engine be insufficient to drive an exhaust gas turbocharger, resulting in the incorrect amount of air for combustion?（）A
During operation at low speedB
During operation at rated speed, but low power outputC
During accelerationD
All of the above
考题
单选题（）, the motion would continue indefinitely once it had started.A
Were there loss of energy by frictionB
Since there be loss of energy by frictionC
Were there no loss of energy by frictionD
Should be no loss of energy by friction
考题
单选题"Scavenging" on a diesel engine means （）.A
injecting fuel oil into a cylinderB
removing exhaust gases from the cylinderC
forcing air into the cylinders under pressure after the exhaust valve has dosedD
a combination of all the above
考题
单选题Scavenging is （） of exhaust gases by blowing in fresh air.A
the suctionB
the compressionC
the removalD
the deliver
考题
单选题In a diesel engine exhaust system, the cooling of the exhaust gases below their dew point, will result in （）A
increased engine back pressureB
sulfuric acid corrosionC
surface pitting of the turbochargerD
moisture impingement on the turbocharger compressor blade
考题
单选题In a two-stroke/cycle diesel engine, the exhaust gases are expelled from the cylinder by the（）A
exhaust manifoldB
valve bridgeC
pressure of the fresh air chargeD
valve adjusting gear
考题
单选题In an engine with air inlet valve and exhaust valve on its cylinder heads the fresh air will enter into the cylinder （） and the gases exhaust （）, there being an adequate overlap between the inlet opening and the exhaust closing.A
downwards；upwardsB
upwards；downwardsC
downwards；downwardsD
upwards；upwards
考题
单选题According to the way the energy of the exhaust gases is utilized, pressure-charging can be divided into two main systems, namely, the constant-pressure system and （）.A
the pulse-phase systemB
the pulse Doppler systemC
the pulse systemD
the pulse interval
考题
单选题When the air charge contacts with the cylinders and pistons and mixes with the residual gases, it will（）A
increase in temperatureB
lose its energy partlyC
expand and do workD
begin to be compressed
考题
单选题The exhaust gases for a new engine should be （） when the engine operates under full load.A
smokyB
a little bit denseC
visibleD
almost invisible
考题
单选题The boiler is fired （） the demand for steam exceeds that available from exhaust gas heating.A
wheneverB
howeverC
whereverD
whether
考题
单选题The process of scavenging a two-stroke/cycle diesel engine serves to（）A
improve fuel flow volumeB
cool the exhaust valvesC
reduce the intake air charge densityD
increase the temperature of exhaust gases
考题
单选题Additional heat extraction from the exhaust gases can be effected by adding an （） section to the unit in plants.A
air coolerB
economizerC
injectorD
air blower
考题
单选题A two-stroke diesel engine exhaust temperature will be lower than a four-stroke diesel engine of the same displacement because the （） (1) scavenging air is cooling the exhaust gases (2) exhaust cycle time is longerA
(1) onlyB
(2) onlyC
both (1) and (2)D
neither (1) nor (2)
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