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

The upper piston rings m large, slow-speed, two-stroke/cycle diesel engines are most effectively lubricated by oil ____.

A.fed from mechanical lubricators

B.thrown off from the main bearings

C.supplied from wick fed drip lubricators

D.flow from a centrifugal or banjo oiler

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

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