单选题The two-stroke cycle begins with the piston coming up from the BDC, with the scavenging ports in the sides of the cylinders being ().AopenBuncoverCcoveredDclosed

单选题
The two-stroke cycle begins with the piston coming up from the BDC, with the scavenging ports in the sides of the cylinders being ().
A

open

B

uncover

C

covered

D

closed


参考解析

解析: 暂无解析

相关考题:

The upper piston rings m large, slow-speed, two-stroke/cycle diesel engines are most effectively lubricated by oil ____.A.fed from mechanical lubricatorsB.thrown off from the main bearingsC.supplied from wick fed drip lubricatorsD.flow from a centrifugal or banjo oiler

Exhaust gases are generally removed from the cylinders of a two-stroke/cycle diesel engine byA.natural aspirationB.masked intake valvesC.air ceilsD.scavenging air

单选题Exhaust gases are generally removed from the cylinders of a two-stroke/cycle diesel engine by()Anatural aspirationBmasked intake valvesCair cellsDscavenging air

单选题The four-stroke cycle begins with the piston ().Acoming up from the BDCBcoming up from the TDCCcoming down from the BDCDcoming down from the TDC

单选题The kids were especially______the coming Christmas because they would get lots of presents from their parents and uncles.Acoming up withBlooking forward toCmaking up forDgetting rid of

单选题In some diesel engine designs,()the injection of cylinder oil is timed to impinge when the piston and only impinge on()Ais coming upward;cylinder ring beltBis going downward;piston ring beltCis coming upward;piston ring beltDis going downward;cylinder ring belt

单选题In order to keep excess oil from the intake ports in two-stroke/cycle diesel engines, ()Awide compression rings are usedBoil rings are located above the pistonCchromium plating is used on all piston ringsDoil rings are located near the bottom of the piston skirt

单选题The camshaft drive is designed to maintain proper camshaft speed relative to crankshaft speedIn maintaining this relationship, the camshaft drive causes the camshaft to rotate at()Aone half crankshaft speed in a two-stroke cycle diesel engineBcrankshaft speed in a two-stroke cycle diesel engineCtwo times crankshaft speed in a two-stroke cycle diesel engineDone-fourth times crankshaft speed in a four-stroke cycle diesel engine

单选题The two-stroke cycle begins with the piston coming up from the bottom of its stroke, with scavenge ports in the sides of the cylinder being ().AshutBclosingCopenedDclosed

单选题The two-stroke cycle begins with the piston coming up from the BDC, with the scavenging ports in the sides of the cylinders being ().AopenBuncoverCcoveredDclosed

单选题When inspecting piston rings through the ports of a two-stroke/cycle diesel engine, black areas on the sealing surfaces are the result of ()Ainsufficient lubricationBimproper piston coolingCblow-byDoverload operation

单选题The exhaust gases in a supercharged two-stroke/cycle diesel engine are expelled from the cylinder by ()Apumping action of the pistonBpressure of the fuel chargeCvacuum developed in the manifoldDpressure of the fresh air charge

单选题The size of the exhaust valve opening is ()Amost critical in a four-stroke cycle diesel engineBmost critical in a two-stroke/cycle diesel engineCmost critical in a four-stroke/cycle diesel engine if it is turbochargedDof equal importance in a two-stroke/cycle diesel engine as in a four-stroke/cycle diesel engine

单选题Proper lubrication of the main bearing is more easily obtained in a single acting four-stroke/cycle diesel engine than in a single acting two-stroke/cycle diesel engine because ()Abearing pressure in a four-stroke/cycle acting single diesel engine is continually reversedBbearing pressure in a two-stroke/cycle single acting diesel engine is continually reversedCthe maximum bearing pressure is higher in a single acting two-stroke/cycle diesel engineDtwo-stoke/cycle diesel engines require more complicated lubrication piping

单选题Oil control rings used in two-stroke/cycle diesel engines are located near the bottom of the piston skirt in order to ()Aincrease the liner area covered by the oil filmBmaintain an oil film on the lower liner where scuffing is prevalentCkeep excess oil away from intake and exhaust portsDhelp cushion piston skirt side thrust by providing a hydrodynamic oil wedge

单选题In diesel engines, the four basic events (intake, compression, power and exhaust) are performed once in ().Atwo crankshaft revolutions in a two-stroke/cycle engineBtwo power strokes in a two-stroke/cycle engineCone power stroke in a two-stroke/cycle engineDtwo piston strokes in a two-stroke/cycle engine

单选题A disadvantage of a four-stroke/cycle diesel engine is ()Ahigher working temperature of piston and cylinderBthe use of scavenge portsCfewer power strokes per revolution of the crankshaftDpart of the fuel is burned as the piston is moving away from top dead center

单选题In a diesel engine, when the fuel is injected into the cylinder,()Athe piston is just coming upward from the bottom dead centerBthe piston has moved about one-fifth of the way upCthe piston has moved most of the way up and almost reached the TDCDthe piston has just past the TDC

单选题A large two-stroke/cycle direct reversing diesel engine is to be reversedPrior to the admission of starting air you must ()Aline up the engine fore restarting with light diesel oilBreposition the fuel injection camCchange the intake and exhaust valve cam positionsDplace the starting cam in the intermediate position

单选题Which of the following statements is true regarding the installation of piston rings on two-stroke/cycle, diesel engines as compared to four-stroke/cycle, diesel engines?()AIn a two-stroke/cycle engine, the rings run hotter, requiring the end gap to be greaterBSome provision must be made in a two-stroke/cycle engine to keep the rings from binding in the portsCNo gap is required to exist between the ends of the ring when cold in a two-stroke/cycle engine, but a small gap is required in a four-stoke/cycle engineDThe gaps should be staggered on either side of a piston in a two-stroke/cycle engine, while staggering is not necessary in a four-stroke/cycle engine

单选题In a two-stroke/cycle diesel engine, the exhaust gases are expelled from the cylinder by the()Aexhaust manifoldBvalve bridgeCpressure of the fresh air chargeDvalve adjusting gear

单选题A two-stroke/cycle diesel engine requires less starting air than a four-stroke/cycle diesel engine, of equal displacement, because the two-stroke/cycle diesel engine()Ahas little or no internal frictionBhas a lower effective compression ratioCoperates with scavenge air under a positive pressureDoperates without energy absorbing intake and exhaust strokes

单选题In a single acting, two-stroke/cycle, diesel generator engine, the power impulse in an individual cylinder occurs ()Aonce every crankshaft revolutionBonce every two crankshaft revolutionsConce every piston strokeDtwice every piston stoke

单选题The rotary motion of a diesel engine crankshaft is obtained from the up and down motion of the piston via the ().AcamshaftBreduction gearsCrocker armDconnecting or piston rod

单选题A disadvantage of a two-stroke/cycle diesel engine is()Amore power strokes per revolutionBthe use of scavenge airCmore complicated valve gearDhigher working temperature of the piston and cylinder

单选题The energy for pushing this piston up can be supplied from (), so that the piston can keep moving up and down.Athe same pistonBthe piston nearbyCthe other pistonsDthe generators on board

单选题A possible cause for an individual piston to knock when at TDC on a slow-speed, two-stroke/cycle main propulsion diesel engine could be due to ()Aearly fuel injectionBexcessive bearing play within the running gearCoverloading of the cylinderDall of the above

单选题In slow speed two-stroke engines,()the fresh air entering begins when and stops as()Athe inlet port is opened by the up coming piston; the port is closed by the down goingBthe inlet valve is opened by the down going piston;the inlet valve is closedCthe inlet port is opened by the down going piston;the port is closed by the up comingDthe inlet valve is opened