单项选择题

Black areas on the sealing surfaces of piston rings indicate（）

A.lube oil pumping
B.rotating rings
C.gas pressure behind the ring
D.passage of hot gases

<上一题 目录 下一题>
热门 试题

单项选择题
When inspecting piston rings through the ports of a two-stroke cycle diesel engine, black areas on the sealing surfaces are the result of （）

A.insufficient lubrication
B.improper piston cooling
C.blow-by
D.overload operation
单项选择题
Visual inspection of chrome-plated piston compression rings reveals a black ring face at the position of the cylinder liner portsThis condition indicates a ring which（）

A.has a crown-face
B.exceeds wear limits through normal wear
C.has excessive blow-by
D.is in good condition
相关试题