单项选择题
If the engine is naturally aspirated, or is a small high-speed type with a centrifugal turbocharger, the period of valve overlap（）,ie when both valves are（）, will be and the exhaust valve will close some 10°top dead canter（）.
A.open；short；after
B.closed；short；after
C.open；long；before
D.closed；long；before
点击查看答案&解析
相关考题
-
单项选择题
（）is the main reason that reduces the power advantage of a two-stroke engine over a same size four-stroke one to about（）
A.Inefficient scavenging；twice
B.Inefficient scavenging；1~8 times
C.Fewer strokes in a circle；twice
D.Fewer strokes in a circle；1~8 times -
单项选择题
In a diesel engine, when the fuel is injected into the cylinder,（）
A.the piston is just coming upward from the bottom dead center
B.the piston has moved about one-fifth of the way up
C.the piston has moved most of the way up and almost reached the TDC
D.the piston has just past the TDC -
单项选择题
One of the differences between a two-stroke engine and a four-stroke engine is,（）
A.a two-stroke engine can’t work without cylinders
B.a two-stroke engine can’t work without pistons
C.a two-stroke engine can’t work without crankshafts
D.a two-stroke engine can’t work without a blower
