单项选择题Valves in the cylinder head of a diesel engine are opened by the direct action of the()

A.exhaust pressure
B.valve spring pressure
C.rocker arm movement
D.wrist pin movement


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1.单项选择题On a large diesel engine installation, crankshaft axial alignment is maintained by the ()

A.piston rod guides
B.engine thrust bearing
C.crosshead bearing
D.main shaft flexible coupling

2.单项选择题A piston is said to be at top dead center when it is ()

A.opening the exhaust ports
B.placed on top of the engine along its centerline
C.farthest from the cylinder head
D.nearest to the cylinder head

3.单项选择题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

4.单项选择题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

5.单项选择题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

6.单项选择题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 indicated horsepower as a four-stroke/cycle engine
D.one power stroke for every two crankshaft revolutions

7.单项选择题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

8.单项选择题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

9.单项选择题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

10.单项选择题A disadvantage of a four-stroke/cycle diesel engine is ()

A.higher working temperature of piston and cylinder
B.the use of scavenge ports
C.fewer power strokes per revolution of the crankshaft
D.part of the fuel is burned as the piston is moving away from top dead center