单项选择题
A.natural aspiration B.masked intake valves C.air cells D.scavenging air
Improperly fitted piston rings in a diesel engine can c...
单项选择题Improperly fitted piston rings in a diesel engine can cause（）
A.excessive lube oil consumption B.lower than normal lube oil temperature C.higher than normal exhaust back pressure D.excessive crankshaft end play
Cold clearances between the skirt of an aluminum piston...
单项选择题Cold clearances between the skirt of an aluminum piston and the cylinder liner is about （）
A.twice as large as with a cast iron piston B.the same size as with a cast iron piston C.half as large as with a cast iron piston D.the same size as the crown of an aluminum piston
Exhaust valve openings in a diesel engine cylinder head...
单项选择题Exhaust valve openings in a diesel engine cylinder head are made as large as practical to （）
A.increase back pressure during the exhaust process B.facilitate periodic replacement of the valves C.reduce the pumping loss associated with scavenging D.reduce tension on valve springs
