單項(xiàng)選擇題A piston is at bottom dead center when it is（）

A.opening the exhaust ports
B.closing the fuel ports
C.farthest from the cylinder head
D.nearest to the cylinder head


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1.單項(xiàng)選擇題The average pressure exerted on piston during each power stroke is termed（）

A.indicated horsepower
B.mean effective pressure
C.exhaust back pressure
D.compression pressure

2.單項(xiàng)選擇題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 indicated horsepower as a four-stroke/cycle engine
D.one power stroke for every two crankshaft revolutions

3.單項(xiàng)選擇題In comparing engines of equal horsepower, higher exhaust gas temperatures occur in a/an（）

A.opposed-piston engine
B.double-acting engine
C.two-stroke/cycle engine
D.four-stroke/cycle engine

4.單項(xiàng)選擇題A disadvantage of a two-stroke/cycle diesel engine is（）

A.more power strokes per revolution
B.the use of scavenge air
C.more complicated valve gear
D.higher working temperature of the piston and cylinder

5.單項(xiàng)選擇題Compared to four-stroke/cycle engines, two-stroke/cycle diesel engines have the disadvantage of （）

A.less even torque
B.higher cylinder head temperatures
C.fewer power strokes per revolution
D.greater weight/size requirements