单项选择题
The flywheel reduces speed fluctuations by （）
A.maintaining a constant rack setting B.storing kinetic energy C.maintaining equal exhaust pressure D.maintaining even camshaft speed
单项选择题 How often should the lubricating oil of a diesel engine be changed?（）
单项选择题 The main function of piston compression rings is to （）
单项选择题 Modern marine diesel engines using mechanical fuel injection, operate on a combustion cycle which is（）
