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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相关考题
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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 -
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 -
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
