單項選擇題During the valve overlap period, the exhaust pressure of a turbochargers, 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


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2.單項選擇題When the normal compression ratio of a diesel engine is not very high, misfiring at light loads may be caused by ()

A.overloading the engine
B.low exhaust valve lift
C.excessive cylinder cooling
D.insufficient mechanical clearance

3.單項選擇題In a two-stroke/cycle diesel engine, the exhaust gases are expelled from the cylinder by the()

A.exhaust manifold
B.valve bridge
C.pressure of the fresh air charge
D.valve adjusting gear

4.單項選擇題If a diesel engine driving a generator turns over freely but fails to fire properly, the cause could be ()

A.excessive compression pressure
B.air in the fuel lines
C.high fuel pressure
D.excessive load

5.單項選擇題One of the purposes for water cooling the exhaust manifold in marine diesel engine is to ()

A.reduce lube oil temperature
B.raise exhaust temperature reduce
C.excessive heating of engine room
D.reduce load on cooling water pump