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单选题
When an air started, four-stroke/cycle diesel engine is being cranked, the starting air is admitted to each cylinder during what would normally be the（）
A
intake stroke
B
compression stroke
C
power stroke
D
exhaust stroke
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单选题A connecting rod in a four-stroke/cycle diesel engine is subject to（）A
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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
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单选题Fuel oil begins injection into the cylinder of a four-stroke/cycle diesel engine during the （）.A
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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
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单选题If a four-stroke/cycle diesel engine is started by injecting air into the cylinder, the pistons receiving the charge of starting air must be（）A
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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 following conditions can cause above normal air temperature to develop in the intake manifold of a four-stroke/cycle turbo-charged diesel engine?（）A
Clogged air intake faltersB
Piston blow-byC
A defective after-coolerD
Faulty exhaust valves
考题
单选题The term diesel engine scavenging means（）A
delivering more air into the cylinder than it would normally receive during an ordinary charging processB
forcing the products of combustion out of the cylinder with the fresh air chargeC
collecting the air charge at the cleanerD
combustion and expansion of hot gas
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单选题During the valve overlap period, the exhaust pressure of a turbochargers, four-stroke/cycle diesel engine must be less than the intake manifold pressure to ensure （）A
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单选题Scavenging in a four-stroke/cycle diesel engine occurs during the （）.A
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early part of the power stroke
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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
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low exhaust pressureD
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improve fuel flow volumeB
cool the exhaust valvesC
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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
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考题
单选题In a four-stroke/cycle diesel engine, after the completion of the power stroke, the piston will move（）A
up and draw in a fresh air chargeB
down to burn off fuelC
down to compress the fuel air chargeD
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单选题In a turbocharged four-stroke/cycle diesel engine, the exhaust valve remains open until after top dead center and the intake valve opens before top dead center to（）.A
produce a scavenging effect in the combustion spaceB
equalize cylinder and exhaust manifold pressuresC
alleviate the difference in valve size between the intake and exhaustD
flush out condensate that collects after each compression stroke
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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Any increase in the exhaust back pressure of a four-stroke/cycle diesel engine will （）.A
reduce engine horsepower outputB
aid in silencing the exhaust noiseC
increase the mean effective pressureD
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单选题For a given size engine, the two-stroke/cycle diesel engine will deliver more power than a four-stroke/cycle diesel engine because （）.A
it has a longer power strokeB
more air gets into the cylinder each strokeC
it develops twice as many power strokes at the same speedD
higher combustion pressure is developed
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单选题In diesel engines, the four basic events (intake, compression, power and exhaust) are performed once in （）.A
two crankshaft revolutions in a two-stroke/cycle engineB
two power strokes in a two-stroke/cycle engineC
one power stroke in a two-stroke/cycle engineD
two piston strokes in a two-stroke/cycle engine
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