海船船员考试
单选题Turbocharged four-stroke/cycle diesel engines utilize valve overlap for（）.A improving cylinder scavengingB preheating the combustion chamberC reducing air charge densityD preventing valve wear
题目
improving cylinder scavenging
preheating the combustion chamber
reducing air charge density
preventing valve wear
相似问题和答案
第1题：
During the valve overlap period, the exhaust pressure of a turbocharged four-stroke/cycle diesel engine must be less than the intake manifold pressure to ensure ______.
A.effective cylinder scavenging and cooling
B.constant pressure from the turbochargers
C.cooler operation of the exhaust system
D.effective constant pressure for turbocharger operation
第2题：
a single, long-stroke, slow-speed, turbocharged, two-stroke diesel engine
a single, long-stroke, medium-speed, turbocharged, four-stroke diesel engine
two medium-speed, turbocharged, four-stroke diesel engines
a variable-speed AC generator
第3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.The direction of pressure on the journal in four-stroke engine is continuously
B.positive feed lubricators are installed on all bearings of four-stroke engine, whereas as a splash feed system is used on tow-stroke engine
C.four-stroke engines usually utilize a heavier grade of oil than tow-stroke engines
D.Low-stroke engines usually consume less lube oil than four-stroke engines
第4题：
The direction of pressure on the journal in four-stroke engine is continuously
positive feed lubricators are installed on all bearings of four-stroke engine, whereas as a splash feed system is used on tow-stroke engine
four-stroke engines usually utilize a heavier grade of oil than tow-stroke engines
Low-stroke engines usually consume less lube oil than four-stroke engines
第5题：
sliding the camshaft along its axis
rotating the cam 180
rotating the cam followers 180
moving the idler sprockets in the drive chain
第6题：
less even torque
higher cylinder head temperatures
fewer power strokes per revolution
greater weight/size requirements
第7题：
one half crankshaft speed in a two-stroke cycle diesel engine
crankshaft speed in a two-stroke cycle diesel engine
two times crankshaft speed in a two-stroke cycle diesel engine
one-fourth times crankshaft speed in a four-stroke cycle diesel engine
第8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 engine
B.twice the indicated horsepower as a four-stroke/cycle engine
C.one half the indicated horsepower as a four-stroke/cycle engine
D.one power stroke for every two crankshaft revolutions
第9题：
most critical in a four-stroke cycle diesel engine
most critical in a two-stroke/cycle diesel engine
most critical in a four-stroke/cycle diesel engine if it is turbocharged
of equal importance in a two-stroke/cycle diesel engine as in a four-stroke/cycle diesel engine
第10题：
inoperative turbocharger
inadequate fuel supply
overload on one cylinder
unequal load distribution