单项选择题
A.Lubrication systems using engine driven lube oil pumps do not require any additional independent arrangement when such arrangements have been proven reliable
B.The use of engine driven pre-lube pumps is permitted on vessels with propulsion systems developing less than 500 shaft horsepower
C.When forced lubrication is used for propulsion engines, one independently driven stand-by pumps is to be provided in addition to the necessary pumps for normal operation
D.Lubrication systems where two oil coolers are fitted require a minimum of two temperature control devices which may be actuated by similar sensors
单项选择题 If the coolant temperature of a closed cooling water system for a diesel engine gradually increases, the trouble usually is （）
单项选择题 The amount of fuel delivered by a helical plunger fuel injection pump is controlled by （）
单项选择题 On a diesel engine equipped with a hydraulic speed control governor, hunting in many cases can be corrected by adjusting the （）