单项选择题
In a medium speed diesel engine, a trunk type piston may be cooled by（） Ⅰ.oil circulation though passages in the piston crown Ⅱ.heat transfer through piston rings and liner wall
A.Ⅰ only B.Ⅱ only C.either Ⅰ or Ⅱ D.neither Ⅰ or Ⅱ
单项选择题 The exhaust system for a turbocharged diesel engine functions to （）
单项选择题 If the analysis of used lube oil indicates a high content of iron particles, this could indicate（）
单项选择题 Late fuel injection timing is indicated by （）
