单项选择题
A.residual carbon deposits
B.lube oil viscosity breakdown
C.uneven heat expansion of the rings
D.uneven heat expansion of the piston
单项选择题 A six-cylinder, two-stroke/cycle diesel engine is fitted with a rotary distributing air starting systemThe speed of the rotating distributor disc is （）
单项选择题 In the cylinder head of a two-stroke/cycle diesel engine, valves are used for（）
单项选择题 Diesel engine piston seizure can be caused by （）