单选题A piston is said to be at top dead center when it is （）Aopening the exhaust portsBplaced on top of the engine along its centerlineCfarthest from the cylinder headDnearest to the cylinder head
单选题
A piston is said to be at top dead center when it is （）
A
opening the exhaust ports
B
placed on top of the engine along its centerline
C
farthest from the cylinder head
D
nearest to the cylinder head
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相关考题：
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单选题In a turbocharged four-stroke/cycle diesel engine, the exhaust valve remains open until after top dead center and the intake valve opens before top dead center to（）.Aproduce a scavenging effect in the combustion spaceBequalize cylinder and exhaust manifold pressuresCalleviate the difference in valve size between the intake and exhaustDflush out condensate that collects after each compression stroke