网友您好， 请在下方输入框内输入要搜索的题目：
题目内容
（请给出正确答案）
单选题
A built-up exhaust valve is one in which （）.
A
the stem and heads are made of different material
B
low-alloy steel is used throughout
C
a replaceable valve disk is welded to the head
D
the self-centering action comes from motion of the valve stem in the guide
参考答案
参考解析
解析：
暂无解析
更多 “单选题A built-up exhaust valve is one in which （）.A the stem and heads are made of different materialB low-alloy steel is used throughoutC a replaceable valve disk is welded to the headD the self-centering action comes from motion of the valve stem in the guide” 相关考题
考题
One of the factors limiting the amount of toad which can be put on a modem marine diesel engine is the_______.A.governor sensitivityB.exhaust temperatureC.fuel injection pressureD.speed of the cam shaft
考题
单选题Your vessel is taking on bunkers from a shore side facility, if oil begins flowing from one tank vent, which of the following actions should be taken FIRST?（）A
Open the intake valve to an adjacent tankB
Set out drip pans and sawdust and begin to mop up the spillC
Signal the shore control point to shutdownD
Close the valve on the tank vent line
考题
单选题The period of valve overlap is when （）.A
the inlet valve is openB
the exhaust valve is openC
both valves are closeD
both valves are open
考题
单选题Valve overlap is the period during which （）.A
the inlet valve is openB
the exhaust valve is openC
both valves are closedD
both valves are open
考题
单选题Which of the following problems represent one possible cause of high lube oil consumption in a four stroke diesel engine?（）A
Worn intake valve guidesB
Pitted pre-combustion chambersC
Loose valve tappetsD
High exhaust back pressure
考题
单选题Which one of following statement is not true concerning the suitable sites of the direct acting relief valve and the pilot operated relieve valve?（）A
the direct acting relief valve is used for controlling lower flows and pressureB
the pilot operated relief valve is used for controlling higher flows and pressureC
the pilot operated relief valve is used for controlling lower flows and pressureD
the controlling accuracy of direct acting relief valve is worse than that of the pilot operated relief valve
考题
单选题In which of the scavenging methods listed will the exhaust valve be located in the cylinder head?（）A
Return-flowB
UniflowC
Cross-flowD
Direct flow
考题
单选题Which of the listed conditions will occur if a diesel engine exhaust valve is leaking?（）A
Loss of compression for that cylinderB
Misfiring or rough runningC
Damage to the valveD
All of the above
考题
单选题Excessively worn, or polished ends on a diesel engine valve spring, indicate（）A
burned exhaust valvesB
excessive spring compressionC
spring surgeD
worn valve seats
考题
单选题Icreasing the exhaust valve tappet clearance of a diesel engine will result in the exhaust valve opening （）A
later and closing earlierB
later and closing laterC
earlier and closing earlierD
earlier and closing later
考题
单选题Leaky exhaust valve will result in which of the following?（） (1) high exhaust temperature; (2) low compression pressure; (3) low firing pressure.A
(1) and (2)B
(1) onlyC
(2) onlyD
(1),(2) and (3)
考题
单选题Each cylinder has one starting valve which is usually opened by air pressure and closed by （）A
nuts and boltsB
new jointsC
spring forceD
sealing rings
考题
单选题Exhaust valve grooving and corrosion is caused by certain components of residual fuel oilThese components are sodium, sulfur, and （）.A
vanadiumB
carbonC
copperD
ash
考题
单选题Exhaust valve openings in a diesel engine cylinder head are made as large as practical to （）A
increase back pressure during the exhaust processB
facilitate periodic replacement of the valvesC
reduce the pumping loss associated with scavengingD
reduce tension on valve springs
考题
单选题Clearance volume scavenging in a turbocharged, four-stroke/cycle diesel engine is accomplished （）.A
during the valve overlap periodB
with only the exhaust valve openC
at a pressure below atmosphericD
without cooling the cylinders or pistons
考题
单选题The arrangement and shape of the cams on a diesel engine camshaft directly control which of the listed groups of operating conditions?（）A
speed, torque, and horsepower productionB
firing order, valve timing, and valve liftC
fuel consumption, efficiency, and cylinder pressureD
scavenge pressure, compression ratio, and exhaust pressure
考题
单选题In an engine with air inlet valve and exhaust valve on its cylinder heads the fresh air will enter into the cylinder （） and the gases exhaust （）, there being an adequate overlap between the inlet opening and the exhaust closing.A
downwards；upwardsB
upwards；downwardsC
downwards；downwardsD
upwards；upwards
考题
单选题The exhaust valve is opened at about the same time （） the air inlet ports are opened.A
beforeB
afterC
whenD
until
考题
单选题High cylinder firing pressure, accompanied by low exhaust temperature, can result from （）A
improper fuel rack positingB
lengthy exhaust valve durationC
extend operation at light loadD
excessively early injection timing
考题
单选题In comparison to exhaust valves, intake valves of diesel engines may be fabricated from low alloy steels because （）.A
the beveled edges of the intake valves provide for serf-centering during seatingB
intake valves utilize stellite-coated valve seat inserts which reduce wearC
the volume of air passing through intake valves is less than the volume of air passing through exhaust valvesD
intake valves are less affected to the corrosive action of exhaust gases
考题
单选题A substance found in residual fuels which tends to cause exhaust valve corrosion and grooving, is（）A
carbonB
vanadiumC
calciumD
hydrogen
考题
单选题When one cylinder has a lower compression pressure and higher exhaust gas temperature than any of the other engine cylinders, which of the conditions listed will indicated?（）A
Advanced ignitionB
Clogged air intakeC
Leaky exhaust valveD
High exhaust pressure
考题
单选题Which of the listed design features is found in an exhaust valve and NOT in an intake valve?（）A
Hard alloy steel constructionB
Beveled edges on the valve headC
Low alloy steel constructionD
Poppet type design
考题
单选题Scavenging in a turbocharged, four-stroke/cycle diesel engine is accomplished（）A
during the valve overlap periodB
with only the exhaust valve openC
at a pressure below atmosphericD
without cooling the cylinders or pistons
考题
单选题In some type of two-stroke engines, besides some small holes for（）, starting valve, safety valve, indicator cock, and central opening in each cylinder cover for mounting the（）A
fuel valves；exhaust valveB
exhaust valves；inlet valveC
fuel valves；inlet valveD
exhaust valves；fuel valve
考题
单选题In a diesel engine, an extremely leaking exhaust valve can cause （）.A
misfiringB
pre-ignitionC
interrupted scavengingD
reduced scavenging
考题
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（）.A
produce a scavenging effect in the combustion spaceB
equalize cylinder and exhaust manifold pressuresC
alleviate the difference in valve size between the intake and exhaustD
flush out condensate that collects after each compression stroke
热门标签
最新试卷