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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 pumps
B
piston cooling pumps
C
exhaust valves
D
all of the above
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更多 “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” 相关考题
考题
单选题Compared to four-stroke/cycle engines, two-stroke/cycle diesel engines have the disadvantage of （）A
less even torqueB
higher cylinder head temperaturesC
fewer power strokes per revolutionD
greater weight/size requirements
考题
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
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The two-stroke cycle begins with the piston coming up from the bottom of its stroke, with scavenge ports in the sides of the cylinder being （）.A
shutB
closingC
openedD
closed
考题
单选题The two-stroke cycle begins with the piston coming up from the BDC, with the scavenging ports in the sides of the cylinders being （）.A
openB
uncoverC
coveredD
closed
考题
单选题In describing engine operation, what does the term “cycle” mean?（）A
The sequence of events that produce a power pulseB
One rotation of the engine crankshaftC
One stroke of a pistonD
All of the above
考题
单选题When inspecting piston rings through the ports of a two-stroke/cycle diesel engine, black areas on the sealing surfaces are the result of （）A
insufficient lubricationB
improper piston coolingC
blow-byD
overload operation
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Large, two-stroke/cycle, main propulsion, diesel engine cylinders can be successfully pressure charged during normal operation, by using the （）.A
exhaust gas temperature systemB
exhaust load systemC
constant or pulse pressure systemD
constant volume system
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If all other conditions such as bore, stroke, speed, and mean effective pressures are equal, a two-stroke/cycle diesel engine will develop approximately（）A
the same indicated horsepower as a four-stroke/cycle engineB
twice the indicated horsepower as a four-stroke/cycle engineC
one half indicated horsepower as a four-stroke/cycle engineD
one power stroke for every two crankshaft revolutions
考题
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
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In a single acting, two-stroke/cycle, diesel generator engine, the power impulse in an individual cylinder occurs （）A
once every crankshaft revolutionB
once every two crankshaft revolutionsC
once every piston strokeD
twice every piston stoke
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The speed of the camshaft in a two-stroke/cycle diesel engine, running at 950 RPM, is （）.A
475 RPMB
950 RPMC
1900 RPMD
2400 RPM
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
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