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单选题The closing of the exhaust valves used on a modern, large, low-speed, main propulsion diesel engine may be directly provided by （）.A large conical springsB compressed air pressureC hydraulic pressureD exhaust gas pressure

题目
单选题
The closing of the exhaust valves used on a modern, large, low-speed, main propulsion diesel engine may be directly provided by （）.
A

large conical springs

B

compressed air pressure

C

hydraulic pressure

D

exhaust gas pressure

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相似问题和答案

第1题：

The closing of the exhaust valves used on a modern, large, low-speed, main propulsion diesel engine may be directly provided by_______.

A.large conical springs

B.compressed air pressure

C.hydraulic pressure

D.exhaust gas pressure


正确答案：B

第2题：

Fuel is admitted to a diesel engine cylinder through the ______.

A.injector nozzles

B.carburetor

C.exhaust ports

D.intake valves


正确答案：A

第3题：

While a ______ amount of stress can be beneficial, too much stress can exhaust you.

(A) modern

(B) moderate

(C) moderation

(D) modest


正确答案：B 
解答参考：B 本题考查词语辨析。modern意为―现代的‖;moderate―适度的‖;moderation是名词，表示―适度‖;modest―谦虚的‖。根据题意，应该选B。【译文】适度的压力是有益的，而过多的压力则会让人筋疲力尽。  

第4题：

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


正确答案： C
解析： 暂无解析

第5题：

单选题
For an ordinary four-stroke diesel engine the exhaust valves close （）.
A

after TDC

B

before TDC

C

after BDC

D

before BDC


正确答案： A
解析： 暂无解析

第6题：

why is quick closing valves important to in engine room machineries ?how are they operated ?


正确答案：These are pneumatically actuted valves ,hydraulic valves and hand actuated valves .they are used for the purpose of shutting and closing the valve down in remote position in case of fire or other emergency . In case of fire , a remote operated valve is actuated to supply control air leading to each valve .these valves are equipped with cylinders with rods which provide a means valve locking ,and control air supplied will activate the cylinder disengage the locking mechanism and shutting the valve .

第7题：

When loading a tanker，you should ______．

A.load only one tank at a time

B.keep the seamen on watch on standby in the mess room

C.keep a strain on the loading hoses

D.close valves by closing them down，reopening one or two turns，and re-closing


正确答案：D

第8题：

Which of the following will be the advantage of a centrifugal pump as compared with a reciprocating pump? l.Its discharge is continuous; ll.It has no internal valves: lll.Upon accidental closing of discharge valve, excessive pressure will not build up()

A.l, ll

B.ll, lll

C.l ,ll.III

D.llonly


答案：C

第9题：

单选题
Air scavenging of a diesel engine cylinder（）
A

blows out the exhaust gases

B

supplies oxygen for combustion

C

cools the valves and cylinder walls

D

all of the above


正确答案： C
解析： 暂无解析

第10题：

单选题
Valve overlap is the period during which （）.
A

the inlet valve is open

B

the exhaust valve is open

C

both valves are closed

D

both valves are open


正确答案： A
解析： 暂无解析

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