The cylinder oil is pumped into the cy...

单项选择题The cylinder oil is pumped into the cylinder (via non-return valves) when the piston rings pass the lubricating orifices during （）

A.the upward stroke
B.the downward stroke
C.the power stroke
D.the suction stroke

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1.单项选择题If there are micro-seized areas on the liner or skirt scratch-over manually with a coarse carbo-rundum stone (grindstone), moving the grindstone （） at an angle of 20 to 30 degrees to horizontal.

A.clockwise
B.anticlockwise
C.crosswise
D.vertically

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2.单项选择题“lover-leafing”is a term used to describe corrosive wear at several separate points around liner circumference- iein some cases the liner bore may assume a “clover-leaf”shape（）

A.transverse
B.longitudinal
C.circumferential
D.radial

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3.单项选择题If the gas pressure behind the ring is built up too slowly, and thereby exerts an inadequate outward pressureIn such a case, the combustion gas can penetrate between the liner and ring, and violently force the ring inwards, in the grooveWhat result will this type of sudden "shock" loading eventually lead to?（）

A.micro-seizure
B.scratch
C.break
D.stick

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4.单项选择题Broken piston rings manifest themselves during the scavenge port inspection by（）

A.Lack of elastic tension, when the rings are pressed into the groove by means of a stick
B.Blackish appearance
C.Fractured rings and missing rings
D.all off the above

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5.单项选择题If due to thick and hard deposits of carbon, the piston rings cannot move freely in their grooves, dark areas will often appear on the upper part of the cylinder wall (may not be the risible at port inspection)What condition of the piston rings can result in this phenomenon?（）

A.micro-seizure
B.sticking
C.scratched
D.breakage/ollapse

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6.单项选择题If over a period of time, the oi1 film partially disappears, so that dry areas are formed on the cylinder wall, these areas and the piston surfaces will by frictional interaction, become finely scuffed and hardened, iegood mirror surface" will have deterioratedWhat condition of the piston rings can result in this phenomenon?（）

A.micro-seizure
B.sticking
C.scratched
D.breakage/collapse

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7.单项选择题When good and steady service conditions have been achieved, the running surfaces of the piston rings and cylinder liner will be（）In addition, the rings will move freely in the grooves and also be well oiled intact, and not unduly worn.

A.hazy light
B.hazy light brown
C.hazy light blue
D.hazy light grey

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8.单项选择题The sealing function of the piston ring is brought about by the gas pressure above and behind the piston ring, which forces it （） against the bottom of the ring groove, and （） against the cylinder wall.

A.upwards；inwards
B.upwards；outwards
C.downwards；inwards
D.downwards；outwards

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9.单项选择题The scavenge port inspection should be carried out（）, to obtain the most reliable result with regard to the effectiveness and sufficiency of the cylinder lubrication and the combustion cycle (complete or incomplete).

A.at the first stop after a long voyage egby anchoring if possible
B.at the first stop after arrival at harbor
C.at the first stop after low load running
D.at the first stop after passing river or canal passage

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10.单项选择题Always ensure that the turning gear is（）, even at the quay, the wake from other ships may turn the propeller and thus the engine.

A.disengaged
B.engaged
C.assembled
D.disassembled

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