单项选择题
A.sea water temperature must never be warmer than 40℃
B.jacket water pressure should always be greater than the sea water pressure
C.jacket water temperature must always be less than 60℃
D.jacket water pressure must always be less than the sea water pressure
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
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（）