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
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（）
A
has little or no internal friction
B
has a lower effective compression ratio
C
operates with scavenge air under a positive pressure
D
operates without energy absorbing intake and exhaust strokes
参考解析
解析：
暂无解析
相关考题：
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
In an operating diesel engine, which of the following conditions is an indication of a leaking air starting valve?A.Noise coming from that air starting valveB.Continuous operation of the starting air compressorC.Zero air pressure in the air starting systemD.Overheated starting air pipe to the cylinder head
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 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Diesel engine starting difficulties due to cold intake air temperatures, can be overcome by using a/an（）Aincrease in starting air pressureBincrease in lube oil viscosityCcompression expansion deviceDjacket water heater
单选题When an air started, four-stroke/cycle diesel engine is being cranked, the starting air is admitted to each cylinder during what would normally be the（）Aintake strokeBcompression strokeCpower strokeDexhaust stroke
单选题Which of the following methods is used to prevent throttling of compressed air through the diesel engine air starting valves?（）AHolding the valve open for a long periodBIncreasing the starting air pressure usedCOpening the stating air valve quicklyDReducing the starting air valve size
单选题A diesel engine is turned at normal cranking speed and no ignition occursThis could be the result of （）Alow lube oil temperatureBlow starting air temperatureCair bubbles in the fuel oil systemDwater in the starting air system
单选题In order to reverse the rotation of a two-stroke/cycle loop scavenged, direct reversing, propulsion diesel engine, the cam positions must be changed for the （）.Astarting air and fuel pumpsBpiston cooling pumpsCexhaust valvesDall of the above
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Which of the two events listed occurs simultaneously in a two-stroke/cycle diesel engine?（）AExhaust and scavengingBScavenging and compressionCIgnition and expansionDExhaust and compression
单选题In the cylinder head of a two-stroke/cycle diesel engine, valves are used for（）Aair intakeBa fuel outletCcooling water inletsDexhausting combustion gas
单选题The exhaust system for a turbocharged two-stroke/cycle diesel engine functions to（）Adischarge exhaust gases and smokeBfurnish energy to the turbochargerCreduce engine room noiseDall of the above
单选题When would the available energy of the exhaust gases of a two-stroke/cycle diesel engine be insufficient to drive an exhaust gas turbocharger, resulting in the incorrect amount of air for combustion?（）ADuring operation at low speedBDuring operation at rated speed, but low power outputCDuring accelerationDAll of the above
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 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The two strokes of a two-stroke/cycle diesel engine are （）Apower and intakeBintake and exhaustCexhaust and compressionDcompression and power
单选题The process of scavenging a two-stroke/cycle diesel engine serves to（）Aimprove fuel flow volumeBcool the exhaust valvesCreduce the intake air charge densityDincrease the temperature of exhaust gases
单选题For a given size engine, the two-stroke/cycle diesel engine will deliver more power than a four-stroke/cycle diesel engine because （）.Ait has a longer power strokeBmore air gets into the cylinder each strokeCit develops twice as many power strokes at the same speedDhigher combustion pressure is developed
单选题If a four-stroke/cycle diesel engine is started by injecting air into the cylinder, the pistons receiving the charge of starting air must be（）Aon the power strokeBon the exhaust strokeCat the end of the power strokeDat the start of the intake stroke
单选题When starting air is admitted, a diesel engine turns over very slowly without firingThe cause may be （）Aan obstruction in an cylinderBwater accumulation in some engine cylindersClow starting air pressureDlow scavenge air pressure
单选题In an operating diesel engine, which of the following condition is an indication of a leaking air starting valve?（）Anoise coming from that air starting valveBcontinuous operation of the starting air compressorCzero air pressure in the air starting systemDoverheated starting air pipe to the cylinder head
单选题A six-cylinder, two-stroke/cycle diesel engine is fitted with a rotary distributing air starting systemThe speed of the rotating distributor disc is （）Aone-half engine speedBthe same as engine speedCtwice engine speedDfour times engine speed
单选题A two-stroke diesel engine exhaust temperature will be lower than a four-stroke diesel engine of the same displacement because the （） (1) scavenging air is cooling the exhaust gases (2) exhaust cycle time is longerA(1) onlyB(2) onlyCboth (1) and (2)Dneither (1) nor (2)