单项选择题
A.of a material harder than the cylinder liner B.properly lubricated C.prevented from compressing D.prevented from rotating during engine operation
Shaker, circulation and spray are the three general met...
单项选择题Shaker, circulation and spray are the three general methods used in（）
A.pre-injection fuel oil treatment B.lube oil filtration C.lube oil purification D.piston cooling
Wristpin bearings are difficult to lubricate because of...
单项选择题Wristpin bearings are difficult to lubricate because of their oscillating motion and（）
A.their free-floating design B.their relatively small size C.the reciprocating motion of the piston D.their position in the lubrication system
Internal combustion engine crankcase vent outlets must ...
单项选择题Internal combustion engine crankcase vent outlets must be equipped with （）
A.hinged rain guards B.corrosion resistant flame screens C.dipsticks for measuring oil levels D.crankcase ventilation fans
