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单选题
During which of the listed piston stroke of a four-stroke/cycle diesel engine, is the piston moving downward?（）
A
Intake stroke
B
Compression stroke
C
Exhaust stroke
D
Pumping stroke
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If all other conditions such as bore, stroke, speed, and mean effective pressures are equal, a two stroke/cycle diesel engine will develop approximatelyA.the same indicated horsepower as a four-stroke/cycle engineB.twice the indicated horsepower as a four-stroke/cycle engineC.one half the indicated horsepower as a four-stroke/cycle engineD.one power stroke for every two crankshaft revolutions
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If the flame from combustion in the cylinder of a four-stroke engine past the piston into the space below, the accumulation of flammable mixture would be ignited, thus resulting in _____.A.the crankcase explosionB.lifting of the cylinder safety valveC.a scavenge fireD.opening of the manhole
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单选题In a single acting, four-stroke/cycle diesel engine, the power impulse in an individual cylinder occurs （）A
once every crankshaft revolutionB
once every two crankshaft revolutionsC
once every piston strokeD
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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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考题
单选题The four-stroke cycle begins with the piston （）.A
coming up from the BDCB
coming up from the TDCC
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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
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power strokeD
exhaust stroke
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单选题Which of the listed conditions can cause lacquer to be deposited on a piston skirt?（）A
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High lube oil temperaturesC
High vanadium content fuelD
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考题
单选题During the suction stroke, the piston is moving （）.A
inwardsB
outwardsC
downwardsD
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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Marine four-stroke diesel engines are mainly （）.A
of crosshead typeB
of trunk piston typeC
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all the above
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Proper lubrication of the main bearings is more easily obtained in a single acting, four-stroke/cycle diesel engine than in a tow-stroke/cycle diesel engine because（）.A
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four-stroke engines usually utilize a heavier grade of oil than tow-stroke enginesD
Low-stroke engines usually consume less lube oil than four-stroke engines
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单选题Scavenging in a four-stroke/cycle diesel engine occurs during the （）.A
last part of the exhaust stroke, and the first part of the intake strokeB
last part of the intake stroke onlyC
early part of the injection stroke onlyD
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考题
单选题A disadvantage of a four-stroke/cycle diesel engine is （）A
higher working temperature of piston and cylinderB
the use of scavenge portsC
fewer power strokes per revolution of the crankshaftD
part of the fuel is burned as the piston is moving away from top dead center
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单选题The cylinder oil is pumped into the cylinder (via non-return valves) when the piston rings pass the lubricating orifices during （）A
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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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Some provision must be made in a two-stroke/cycle engine to keep the rings from binding in the portsC
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考题
单选题If the flame from combustion in the cylinder of a four-stroke engine past the piston into the space below, the accumulation of flammable mixture would be ignited, thus resulting in （）.A
the crankcase explosionB
lifting of the cylinder safety valveC
a scavenge fireD
opening of the manhole
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
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考题
单选题During the power stroke of a four-stroke/cycle diesel engine, most of the side thrust of a trunk-type piston is absorbed by the（）A
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pinionC
crossheadD
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考题
单选题On a four-stroke diesel engine, when the piston is driven downwards by the expanding gas, it delivers power to the crankshaft through the （）.A
thrust blockB
sounding rodC
connecting rodD
push rod
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单选题It is during （） that work energy is being put into the engine; during the other 3 strokes of the piston, the engine is having to do the work.A
the suction strokeB
the compression strokeC
the expansion strokeD
the exhaust stroke
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单选题In the two stroke diesel engine, it is designed so that the oil impingement is timed to proceed only on the piston ring belt during（）A
compression strokeB
suction strokeC
expansion strokeD
exhaust stroke
考题
单选题Fuel oil begins injection into the cylinder of a four-stroke/cycle diesel engine during the （）.A
intake strokeB
exhaust strokeC
power strokeD
compression stroke
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单选题Which of the devices listed is common to all types of pumps?（）A
A power end and fluid endB
A propeller and educatorC
A volute and impellerD
A turbine and piston
考题
单选题The average pressure exerted on piston during each power stroke is termed（）A
indicated horsepowerB
mean effective pressureC
exhaust back pressureD
compression pressure
考题
单选题A piston in a four-stroke/cycle diesel engine makes four strokes during each （）.A
crankshaft revolutionB
mechanical cycle of operationC
period of two combustion cyclesD
cycle of two events
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