单项选择题
Exhaust gases are generally removed from the cylinders of a two-stroke/cycle diesel engine by（）
A.natural aspiration B.masked intake valves C.air cells D.scavenging air
单项选择题 Improperly fitted piston rings in a diesel engine can cause（）
单项选择题 Cold clearances between the skirt of an aluminum piston and the cylinder liner is about （）
单项选择题 Exhaust valve openings in a diesel engine cylinder head are made as large as practical to （）
