单选题Why are some diesel engine cylinder liners plated on the wearing surface with porous chromium?（）AThe chromium will not wear out the piston ringsBThe chromium strengthens the liners in the way of the scavenging air portsCChromium eliminates the need for oil scraper ringsDPores in the plating aid in maintaining the lube oil film
单选题
Why are some diesel engine cylinder liners plated on the wearing surface with porous chromium?（）
A
The chromium will not wear out the piston rings
B
The chromium strengthens the liners in the way of the scavenging air ports
C
Chromium eliminates the need for oil scraper rings
D
Pores in the plating aid in maintaining the lube oil film
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