The upper piston rings m large, slow-speed, two-stroke/cycle diesel engines are most effectively lubricated by oil ____.

A．fed from mechanical lubricators

B．thrown off from the main bearings

C．supplied from wick fed drip lubricators

D．flow from a centrifugal or banjo oiler

[单选题]The piston rings are manufactured with a diameter （） the bore of the cylinder.A . larger thanB . smaller thanC . equal toD . none of the above

[单选题]Among the rings of a piston the （） one is subjected to the greatest load and temperature.A . bottomB . middleC . topD . none of the above

[单选题]The piston rings if found worn out （） and supplied by shipchandler.A . must replaceB . must to be equippedC . has to be repairedD . have to be renewed

[单选题]These piston rings are so badly worn that they must be （）.A . renewedB . weldedC . machinedD . chromium-plated

[单选题]In a large, slow-speed, main propulsion diesel engine, which of the parts listed is under tension when the engine is running?（）A . Bed plateB . ColumnC . EntablatureD . Tie rod

[单选题]Mist detectors used on large low-speed main propulsion diesel engines monitor and check for the presence of （）.A . fuel oil vapor at the sludge tank ventB . unburned fuel vapors in the scavenge air receiverC . lube oil vapors in the crank caseD . lub

[单选题](piston area)×(piston stroke)×(numbers of the cylinders)=engine( ).A．brake horsepowerB．displacementC．cylinder volumeD．cylinder clearance

[单选题]The sealing rings are in four parts and pressed together around the piston rods by means of _____A．nutsB．boltsC．coil springsD．stuffing boxes

[单选题]The sealing rings are in four parts and pressed together around the piston rods by means of （）.A . nutsB . boltsC . coil springsD . stuffing boxe

[单选题]Writingisaslowprocess,requiring________thought,time,andeffort.A．)significantB)considerableC．)enormousD)numerous