單項選擇題Diesel engine mufflers accomplish noise reduction by （）

A.reducing exhaust gas velocity
B.increasing the frequency of gas vibration
C.the use of long head pipes
D.the use of zinc electrodes


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1.單項選擇題An indication of an overloaded main propulsion diesel engine is （）

A.white smoke in the exhaust
B.high exhaust gas pyrometer readings
C.sparks in the exhaust
D.blue smoke in the exhaust

2.單項選擇題The most practical way of detecting an overload in one cylinder of an operating large, low-speed ,main propulsion diesel engine is to （）

A.check the cylinder exhausts for black smoke
B.listen for combustion knock in that cylinder
C.isolate each cylinder and inspect the injector
D.check the cylinder exhaust temperature frequently

3.單項選擇題Diesel engine mufflers or silencers reduce the engine exhaust noise by （）

A.passing the exhaust through long head pipes
B.diffusing exhaust vibrations through activated carbon baffles
C.increasing the exhaust gas velocity
D.reducing the exhaust gas velocity

4.單項選擇題If a diesel engine were running at 20% overload with a smoky exhaust, you should（）

A.stop the engine immediately to prevent damage
B.increase lube oil pressure
C.slow the engine allowing it to gradually cool
D.decrease the cooling water it temperature to the water jacket

5.單項選擇題A substantial increase pressure could be an indication of a/an （）

A.worn cylinder liner
B.faulty cylinder relief valve
C.excessive lube oil pressure
D.excessive scavenge air pressure