In any diesel engine closed freshwater cooling system, the lowest pressure exists at the _

Immediately after any diesel engine is started, the engineer should check the ______.

A.crankcase pressure

B.lube oil pressure

C.saltwater pressure

D.exhaust temperature

If the compression ratio is increased on any diesel engine, ________.

A.the expansion ratio will decrease

B.combustion will be slowed down

C.thermal efficiency will decrease

D.thermal efficiency will increase

If you are unable to stop a diesel engine by any other means，you should ______．

A.Discharge a CO2 extinguisher in the air inlet

B.Pull off the distributor cap

C.Secure the jacket water

D.Secure the starting air supply valve

Any increase in the exhaust back pressure of a four-stroke/cycle diesel enginewill().

A.reduce engine horsepower output

B.aid in silencing the exhaust noise

C.increase the mean effective pressure

D.contribute to effective cylinder scavenging

A.45

B.60

C.90

D.100

A.prevent engine back pressure at heavy loads

B.increase total engine efficiency at low loads

C.prevent boiler corrosion at low engine loads

D.improve engine fuel consumption at any load

A．setting tank

B．a service tank

C．a head tank

D．an expansion joint

A．at any time

B．only after the engine room control station is switched to “bridge control”

C．whenever the secondary station is switched to "bridge control"

D．with the approval of the chief engineer only

A.Oil level

B.Flow of cooling water

C.Exhaust discharge

D.All of the above

Piston compression rings used in a diesel engine function to _________.

A.transfer heat from the cylinder to the piston

B.scrape oil from the sides of the piston

C.seal the combustion space from the crankcases

D.prevent any piston contact with the cylinder liner