單項(xiàng)選擇題

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

微信掃碼免費(fèi)搜題