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单选题
The period of valve overlap is when （）.
A
the inlet valve is open
B
the exhaust valve is open
C
both valves are close
D
both valves are open
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单选题Scavenging in a turbocharged, four-stroke/cycle diesel engine is accomplished（）A
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单选题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
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单选题In the piping systems of a vessel，what type of valve gives the least resistance to fluid flow when fully open?（）.A
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考题
单选题Usually we take the cooling effect of the air flown through the cylinder during the overlap period as（）A
inevitableB
harmfulC
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