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（）is harmful for fuel pumps, fuel valves, cylinder liner, exhaust valve seats, and the turbocharger blades as well.
A . Bad combustion of the fuel
B . Bad atomization of the fuel
C . Liquid contaminants
D . Solid contaminant
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The loss of the diesel engine cylinder air charge through leaky valves, piston rings, worn or scored liners, would be indicated by which of the following sets of conditions?（）
A . Low compression pressure and high exhaust temperature
B . Low firing pressure and high exhaust temperature
C . Low compression pressure and low exhaust temperature
D . Low firing pressure and low exhaust temperature
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Which of the listed cylinder liner surface conditions indicates proper lubrication?（）
A . Dull black appearance
B . Bright appearance
C . Thin layer of lacquer
D . Thick oily film
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A single piece（） fitted with bronze rings guides the piston in the cylinder liner.
A . piston skirt
B . piston crown
C . guide way
D . cross-head
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Cold clearances between the skirt of an aluminum piston and the cylinder liner is about （）
A . twice as large as with a cast iron piston
B . the same size as with a cast iron piston
C . half as large as with a cast iron piston
D . the same size as the crown of an aluminum pisto
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Improper cooling of a diesel engine cylinder liner due to the accumulation of scale deposits may cause （）.
A . low compression pressure
B . increased piston wear
C . increased cylinder lube oil consumption
D . poor contact between compression rings and liner
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In order to keep the oil film on the cylinder liner during the running-in period, the piston rings are slightly rounded（）
A . on both the external and internal top edges
B . on both the external top and bottom edges
C . on both the external and internal bottom edges
D . on all the four edge
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The cylinder head, cylinder liner and （） form the combustion chamber.
A . frame
B . piston
C . crankcase
D . explosion plate
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A number of cylinder liners are enclosed in one cast iron casing to form a （）.
A . cylinder cover
B . cylinder block
C . cylinder frame
D . bed-plate
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Which of the following operation will have a direct impact on the rate of wear in a cylinder liner （）
A . amount of scavenge air to the cylinder
B . quality of fuel injected
C . viscosity of the lube oil
D . compression ratio of the pisto
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In a diesel engine, excessive cylinder liner wear will cause （） (1) increased blow-by (2) wear between the piston ring and groove
A . (1) only is correct
B . (2) only is correct
C . both (1) and (2) are correct
D . neither (1) or (2) axe correct
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All the rings are slightly rounded on their external top and bottom edges to keep the oil film on the cylinder liner during （） for new piston rings.
A . the running-in period
B . the running process
C . gas exchange process
D . the boiler firing
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The cylinder is fitted with internal liner so that a water space is left （） the liner and the outer wall.
A . around
B . among
C . in
D . betwee
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The rate of wear on a cylinder liner depends on the （）
A . quality of air filtration
B . effectiveness of lubrication
C . type of fuel used
D . all of the above
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In addition to lubricating, cylinder oil assists in forming a gas seal and contains （） which clean the cylinder liner.
A . additives
B . water
C . grease
D . acid solutio
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The cylinder covers and the liners are bolted together by means of studs （） the cylinder frames.
A . screwing into
B . being screw on
C . to screw on
D . screwed into
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The space between cylinder liner and jacket is called （）.
A . the cooling water
B . the circulating water
C . the cooler
D . the cooling water space
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Each cylinder liner on the marine medium speed engines （）.
A . is usually cooled by sea water
B . can be replaced when worn out
C . is in direct contact with the water in the bore of the cylinder
D . can t expand when heated
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Which of the following statements concerning cylinder liner wear is true?（）
A . Liner wear is distributed equally between the upper and lower portions of the cylinder
B . Excessive liner wear causes wear between piston ring and groove
C . Excessive, but uniform liner wear will not cause wear between piston ring and groove
D . Liner wear is normally greatest in the middle of the cylinder
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One advantage of dry cylinder liners used in a diesel engine is the（）
A . lower thermal expansion rates than wet liners
B . greater heat transfer rate than wet liners
C . greater wear resistance than wet liners
D . procedure to replace dry liners is simpler than for wet liner
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Scuffed cylinder liner surfaces in a diesel engine can result form（）
A . starting the engine hot
B . knurling the piston skirt
C . operating an overheated engine
D . using scuff resistant piston ring
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In a diesel engine, an integral liner is one in which the cooling water （） Ⅰ.flows through the cylinder liner jackets Ⅱ.touches the outer side of the liner
A . Ⅰ only
B . Ⅱ only
C . both Ⅰ and Ⅱ
D . neither Ⅰ and Ⅱ
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The cylinder covers and the liners are bolted together by means of （）.
A . bolts welded into the cylinder head
B . bolts welded into the cylinder frames
C . studs screwed into the cylinder head
D . studs screwed into the cylinder frame
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One advantage of dry cylinder liners used in a diesel engine is the_________.
A.lower thermal expansion rates than wet liners
B.greater heat transfer rate than wet liners
C.greater wear resistance than wet liners
D.procedure to replace dry liners is simpler than for wet liners
