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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 friction
B
has a lower effective compression ratio
C
operates with scavenge air under a positive pressure
D
operates without energy absorbing intake and exhaust strokes
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更多 “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 operates with scavenge air under a positive pressureD operates without energy absorbing intake and exhaust strokes” 相关考题
考题
Exhaust gases are generally removed from the cylinders of a two-stroke/cycle diesel engine byA.natural aspirationB.masked intake valvesC.air ceilsD.scavenging air
考题
In an operating diesel engine, which of the following conditions is an indication of a leaking air starting valve?A.Noise coming from that air starting valveB.Continuous operation of the starting air compressorC.Zero air pressure in the air starting systemD.Overheated starting air pipe to the cylinder head
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
one half crankshaft speed in a two-stroke cycle diesel engineB
crankshaft speed in a two-stroke cycle diesel engineC
two times crankshaft speed in a two-stroke cycle diesel engineD
one-fourth times crankshaft speed in a four-stroke cycle diesel engine
考题
单选题Diesel engine starting difficulties due to cold intake air temperatures, can be overcome by using a/an（）A
increase in starting air pressureB
increase in lube oil viscosityC
compression expansion deviceD
jacket water heater
考题
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 strokeB
compression strokeC
power strokeD
exhaust stroke
考题
单选题Which of the following methods is used to prevent throttling of compressed air through the diesel engine air starting valves?（）A
Holding the valve open for a long periodB
Increasing the starting air pressure usedC
Opening the stating air valve quicklyD
Reducing the starting air valve size
考题
单选题A diesel engine is turned at normal cranking speed and no ignition occursThis could be the result of （）A
low lube oil temperatureB
low starting air temperatureC
air bubbles in the fuel oil systemD
water in the starting air system
考题
单选题In order to reverse the rotation of a two-stroke/cycle loop scavenged, direct reversing, propulsion diesel engine, the cam positions must be changed for the （）.A
starting air and fuel pumpsB
piston cooling pumpsC
exhaust valvesD
all of the above
考题
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
考题
单选题Which of the two events listed occurs simultaneously in a two-stroke/cycle diesel engine?（）A
Exhaust and scavengingB
Scavenging and compressionC
Ignition and expansionD
Exhaust and compression
考题
单选题In the cylinder head of a two-stroke/cycle diesel engine, valves are used for（）A
air intakeB
a fuel outletC
cooling water inletsD
exhausting combustion gas
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
bearing pressure in a four-stroke/cycle acting single diesel engine is continually reversedB
bearing pressure in a two-stroke/cycle single acting diesel engine is continually reversedC
the maximum bearing pressure is higher in a single acting two-stroke/cycle diesel engineD
two-stoke/cycle diesel engines require more complicated lubrication piping
考题
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
考题
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
reposition the fuel injection camC
change the intake and exhaust valve cam positionsD
place the starting cam in the intermediate position
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
In a two-stroke/cycle engine, the rings run hotter, requiring the end gap to be greaterB
Some provision must be made in a two-stroke/cycle engine to keep the rings from binding in the portsC
No gap is required to exist between the ends of the ring when cold in a two-stroke/cycle engine, but a small gap is required in a four-stoke/cycle engineD
The gaps should be staggered on either side of a piston in a two-stroke/cycle engine, while staggering is not necessary in a four-stroke/cycle engine
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The two strokes of a two-stroke/cycle diesel engine are （）A
power and intakeB
intake and exhaustC
exhaust and compressionD
compression and power
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
考题
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
on the power strokeB
on the exhaust strokeC
at the end of the power strokeD
at the start of the intake stroke
考题
单选题When starting air is admitted, a diesel engine turns over very slowly without firingThe cause may be （）A
an obstruction in an cylinderB
water accumulation in some engine cylindersC
low starting air pressureD
low scavenge air pressure
考题
单选题In an operating diesel engine, which of the following condition is an indication of a leaking air starting valve?（）A
noise coming from that air starting valveB
continuous operation of the starting air compressorC
zero air pressure in the air starting systemD
overheated starting air pipe to the cylinder head
考题
单选题A six-cylinder, two-stroke/cycle diesel engine is fitted with a rotary distributing air starting systemThe speed of the rotating distributor disc is （）A
one-half engine speedB
the same as engine speedC
twice engine speedD
four times engine speed
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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