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单选题
The size of the exhaust valve opening is （）
A
most critical in a four-stroke cycle diesel engine
B
most critical in a two-stroke/cycle diesel engine
C
most critical in a four-stroke/cycle diesel engine if it is turbocharged
D
of equal importance in a two-stroke/cycle diesel engine as in a four-stroke/cycle diesel engine
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更多 “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” 相关考题
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A dry-type spark arrestor removes sparks from a diesel engine exhaust by ____.A.increasing the linear velocity of the exhaust gasesB.changing directions of exhaust gas flowC.decreasing the temperature of the exhaust gasesD.accelerating the exhaust gas through a reduced size orifice
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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
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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
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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
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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
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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 shaftB
compressed air pressureC
hydraulic “push rods”D
direct action of the main piston moving down
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A warmer than normal compressor suction line might be caused by （）.A
insufficient lubricationB
insufficient refrigerantC
excess refrigerantD
excessive opening of the expansion valve
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
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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A dry-type spark arrestor removes sparks from a diesel engine exhaust by（）A
increasing the linear velocity of the exhaust gasesB
changing directions of exhaust gas flowC
decreasing the temperature of the exhaust gasesD
accelerating the exhaust gas through a reduced size orifice
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
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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
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