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单选题
The opening of an exhaust valve on a modem, large, low-speed, main propulsion diesel engine may be actuated by （）.
A
direct action of cam shaft
B
compressed air pressure
C
hydraulic “push rods”
D
direct action of the main piston moving down
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更多 “单选题The opening of an exhaust valve on a modem, large, low-speed, main propulsion diesel engine may be actuated by （）.A direct action of cam shaftB compressed air pressureC hydraulic “push rods”D direct action of the main piston moving down” 相关考题
考题
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
考题
All marine low-speed diesels are of what design ________．A.Four-strokeB.Two-strokeC.Electronic ignitionD.Forced exhaust
考题
单选题The opening or closing of the cylinder starting valve is controlled by （）.A
the starting air distributorB
the cut-off valve on the air mainC
the main starting valveD
the air bottle control valve
考题
单选题Which of the conditions listed would cause simultaneous high cylinder firing pressure and low exhaust temperature?（）A
Improper fuel rack positioningB
Lengthy opening of the exhaust valveC
Excessively early injection timingD
Extended light load operation
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The size of the exhaust valve opening is （）A
most critical in a four-stroke cycle diesel engineB
most critical in a two-stroke/cycle diesel engineC
most critical in a four-stroke/cycle diesel engine if it is turbochargedD
of equal importance in a two-stroke/cycle diesel engine as in a four-stroke/cycle diesel engine
考题
单选题In each cylinder cover is a large central opening for mounting （）A
the indicating cockB
the starting valveC
air inlet valveD
the exhaust valve
考题
单选题The most practical way of detecting an overload in one cylinder of an operating large, low-speed ,main propulsion diesel engine is to （）A
check the cylinder exhausts for black smokeB
listen for combustion knock in that cylinderC
isolate each cylinder and inspect the injectorD
check the cylinder exhaust temperature frequently
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Opening of the cylinder （） will admit compressed air into the cylinder.A
safety valveB
indicator cockC
blow-down valveD
start valve
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
考题
单选题A large two-stroke/cycle direct reversing diesel engine is to be reversedPrior to the admission of starting air you must （）A
line up the engine fore restarting with light diesel oilB
reposition the fuel injection camC
change the intake and exhaust valve cam positionsD
place the starting cam in the intermediate position
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A fuel injection valve opening at pressure lower than normal will result in（）.A
late fuel injectionB
early fuel injectionC
high exhaust temperature from that cylinderD
decreased effective stroke from that injector
考题
单选题When the heat load begins to increase, the needle valve of an expansion valve will（）A
move in an opening directionB
move in a closing directionC
either open or closeD
not move at all
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Valve cages are used on some large diesel engines to （）A
reduce wear on the valve stemB
permit the use of alloy valve seat materialsC
reduce heat transfer from the valve seatD
facilitate valve removal for servicing
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
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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
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 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
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