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单选题
The exhaust gases in a supercharged two-stroke/cycle diesel engine are expelled from the cylinder by （）
A
pumping action of the piston
B
pressure of the fuel charge
C
vacuum developed in the manifold
D
pressure of the fresh air charge
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单选题Compared to four-stroke/cycle engines, two-stroke/cycle diesel engines have the disadvantage of （）A
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单选题In a four-stroke/cycle diesel engine, after the completion of the power stroke, the piston will move（）A
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单选题The camshaft drive is designed to maintain proper camshaft speed relative to crankshaft speedIn maintaining this relationship, the camshaft drive causes the camshaft to rotate at（）A
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crankshaft speed in a two-stroke cycle diesel engineC
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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) MEP is lower and the scavenging air is cooling the exhaust gases (2) valve overlap in a four-strokeA
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单选题The exhaust system of a diesel engine is usually designed to remove exhaust gases and to （）A
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power a reciprocating superchargerD
muffle exhaust gas noise
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单选题The size of the exhaust valve opening is （）A
most critical in a four-stroke cycle diesel engineB
most critical in a two-stroke/cycle diesel engineC
most critical in a four-stroke/cycle diesel engine if it is turbochargedD
of equal importance in a two-stroke/cycle diesel engine as in a four-stroke/cycle diesel engine
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单选题Which of the two events listed occurs simultaneously in a two-stroke/cycle diesel engine?（）A
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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
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单选题In the cylinder head of a two-stroke/cycle diesel engine, valves are used for（）A
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a fuel outletC
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单选题What color exhaust will be exhibited when a slow speed two-stroke/cycle main propulsion diesel engine, designed to operate on light and heavy fuel oil, is operated on insufficiently preheated heavy fuel oil?（）A
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BlackC
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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
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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 speedB
During operation at rated speed, but low power outputC
During accelerationD
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单选题Proper lubrication of the main bearing is more easily obtained in a single acting four-stroke/cycle diesel engine than in a single acting two-stroke/cycle diesel engine because （）A
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单选题In diesel engines, the four basic events (intake, compression, power and exhaust) are performed once in （）.A
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two power strokes in a two-stroke/cycle engineC
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单选题In a diesel engine exhaust system, the cooling of the exhaust gases below their dew point, will result in （）A
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单选题A large two-stroke/cycle direct reversing diesel engine is to be reversedPrior to the admission of starting air you must （）A
line up the engine fore restarting with light diesel oilB
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考题
单选题Which of the following statements is true regarding the installation of piston rings on two-stroke/cycle, diesel engines as compared to four-stroke/cycle, diesel engines?（）A
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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
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单选题A two-stroke/cycle diesel engine requires less starting air than a four-stroke/cycle diesel engine, of equal displacement, because the two-stroke/cycle diesel engine（）A
has little or no internal frictionB
has a lower effective compression ratioC
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operates without energy absorbing intake and exhaust strokes
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单选题The two strokes of a two-stroke/cycle diesel engine are （）A
power and intakeB
intake and exhaustC
exhaust and compressionD
compression and power
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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
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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
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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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