单选题Diesel engine automated control systems may utilize sensing devices of dual function, with sensing ranges providing both alarm and engine shut down capability.Which of the key points would only require an alarm sensor?（）A Lube oil pressure and temperat

A bypass line provided around a waste heat auxiliary boiler in a diesel engine exhaust system, may be used to avoid boiler ______.

A.corrosion at low engine loads

B.erosion at high engine loads

C.overload at high engine loads

D.scaling at all exhaust temperatures

Fuel droplets injected into a diesel engine cylinder must have adequate penetration to ____.

A.prolong the ignition delay period

B.ensure the beginning of fuel injection

C.thoroughly utilize the air charge

D.allow controlled fuel combustion

Which of the following statements concerning the lubrication of diesel propulsionengines used in vessels over 300 gross tons is most accurate? ( )

A.Lubrication systems using engine driven lube oil pumps do not require any additionalindependent arrangement when such arrangements have been proven reliable.

B.The use of engine driven pre-lube pumps is permitted on vessels with propulsionsystems developing less than 500 shaft horsepower.

C.When forced lubrication is used for propulsion engines , one independently drivenstandby pumps is to be provided in addition to the necessary pumps for normaloperation.

D.Lubrication systems where two oil coolers are fitted require a minimum of twotemperature control devices which may be actuated by similar sensors.