How does combustion air enter the cylinder of a two-cycle diesel engine ? Through _______．A.Cylinder head valvesB.PortsC.Turbo chargersD.Bleeder valves
How does combustion air enter the cylinder of a two-cycle diesel engine ? Through _______．
A.Cylinder head valves
B.Ports
C.Turbo chargers
D.Bleeder valves
相关考题：
Fuel droplets injected into a diesel engine cylinder must have adequate penetration to ____.A.prolong the ignition delay periodB.ensure the beginning of fuel injectionC.thoroughly utilize the air chargeD.allow controlled fuel combustion
Which of the following statements represents the function of the compression rings installed at the top of a diesel Engine piston?A.Control the amount of lube oil burned in the combustion chamberB.Transmit heat from the piston to the cylinder linerC.Prevent damage to ring groove inserts by acting as a heat damD.Dissipate combustion chamber gas pressure by channeling it through the ring gap
If the diesel engine fuel injection timing is changed to delay the start of injection until the pistons are at top dead center, the engine will_________.A.backfire through the air intakesB.develop less power under loadC.have high firing pressuresD.lift its cylinder relief valves
Diesel engine blow-by is the leakage of combustion gases past the( ).A.oil rings onlyB.compression and scraper ringsC.cylinder liner sealingD.cylinder liner ring grooves
第一组： The Wartsila 50DF operates on the lean-bum principle: the mixture of air and gas in the cylinder has more air than is needed for complete combustion. Lean combustion reduces peak temperatures and therefore NOx emissions. Efficiency is increased and higher output is reached while avoiding knocking. Combustion of the lean air-fuel mixture is initiated by injecting a small amount of LFO (pilot fuel) into the cylinder. The pilot fuel is ignited in a conventional diesel process, providing a high-energy ignition source for the main engine. To obtain the best efficiency and lowest emissions, every cylinder is individually controlled to ensure operation at the correct air-fuel ratio and with the correct amount and timing of pilot fuel rejection. Wartsila has developed a special electronic control system to cope with the demanding task of controlling the combustion in each cylinder, and to ensure optimal performance in terms of efficiency and emissions under all conditions by keeping each cylinder within the operating window. Stable and well-controlled combustion also contributes to less mechanical and thermal load on the engine components. Current stringent emission regulations demand the reduction of NOx emissions. In an internal combustion engine this means controlling peak temperature and residence time, which are the main parameters governing NOx formations. In the Wartsila 50DF engine, the air-fuel ratio is very high (typically 2.2). Since the same specific heat quantity released by combustion is used to heat up a larger mass of air, the maximum temperature and consequently NOx formation are lower. The mixture is uniform. throughout the cylinder since the fuel and air are premixed before introduction into the cylinders, which helps to avoid local NOx formation points within the cylinder. Benefiting from this unique feature, NOx emissions from the Wartsila 50DF are extremely and comply with the most stringent existing legislation.What is the combustion feature of the Wartsila 50DF?A.Lean air in the cylinderB.Excessive fuel in the cylinderC.Excessive air in the cylinderD.Spark ignition
Diesel engines obtain combustion air through turbo chargers，blowers，or ______．A.Air startersB.CarburetorsC.Natural aspirationD.Air receivers
单选题Air scavenging of a diesel engine cylinder（）Ablows out the exhaust gasesBsupplies oxygen for combustionCcools the valves and cylinder wallsDall of the above
单选题Poor combustion in a diesel engine can be caused by （）.Ahigh compression pressureBlow intake air temperatureClow exhaust pressureDhigh scavenge air temperature
单选题Which of the following statements represents the function of the compression rings installed at the top of a diesel Engine piston?（）AControl the amount of lube oil burned in the combustion chamberBTransmit heat from the piston to the cylinder linerCPrevent damage to ring groove inserts by acting as a heat damDDissipate combustion chamber gas pressure by channeling it through the ring gap
单选题The most serious effect of air trapped in a diesel engine jacket water cooling system is that it（）.Acauses colloid suspension in the cooling waterBreduces the capability of the lubrication systemCcan form pockets which block the flow of coolant through the systemDleads to the scuffing of cylinder walls
单选题The term diesel engine scavenging means（）Adelivering more air into the cylinder than it would normally receive during an ordinary charging processBforcing the products of combustion out of the cylinder with the fresh air chargeCcollecting the air charge at the cleanerDcombustion and expansion of hot gas
单选题The diesel engine is a type of internal combustion engine which ignites the fuel by injecting it into hot, high pressure air in a （）.Aair bottleBair compressorCcrank caseDcombustion chamber
单选题If the diesel engine fuel injection timing is changed to delay the start of injection until the pistons are at top dead center, the engine will（）Abackfire through the air intakesBdevelop less power under loadChave high firing pressuresDlift its cylinder relief valves
单选题As for a diesel engine, lack of combustion air may be due to （）.Afouling turbineBfuel pump faultsClubrication failureDexcessive cooling
单选题How does combustion air enter the cylinder of a two-cycle diesel engine?（）ACylinder head valvesBPortsCTurbo chargersDBleeder valves
单选题Combustion gases formed in the cylinder of a diesel engine are prevented from blowing past the piston by （）Acylinder valvesBcompression ringsCpiston skirtsDoil rings
单选题The longer the ignition delay period occurs in a diesel engine, the （）.Aless fuel will enter the cylinderBlower will be cylinder compression temperaturesCmore complete will be fuel combustionDmore rapid will be the rise in combustion pressure
单选题If the engine does start on air, but combustion does not immediately begin, the cause may be （）.Afailure of the fuel pumpsBstarting air pressure too lowCstop valve in air line closedDthe turning gear still engaged
单选题Fuel is admitted to a diesel engine cylinder through the （）.Aintake valvesBcarburetorCexhaust portsDinjector nozzles
单选题Which statement about diesel engine combustion is true?（）ACombustion does not begin until the piston starts down on the power strokeBMaximum combustion pressure is reached before TDCCTurbulence in the cylinder causes a delay in ignitionDMaximum cylinder firing pressure is not developed until the piston passes TDC
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The function of diesel engine piston compression rings is to （）.Aprevent piston side thrustBprevent engine friction lossesCtransmit heat from the piston to the cylinder linerDremove oil from the cylinder combustion space
单选题Fuel droplets injected into a diesel engine cylinder must have adequate penetration to （）Aprolong the ignition delay periodBensure the beginning of fuel injectionCthoroughly utilize the air chargeDallow controlled fuel combustion
单选题The air required for combustion is taken from the engine room through a filter fitted on the turbochargerThis reduces the risk for too and contamination of the combustion air（）Ahigh temperaturesBlow temperaturesCwetDdirty
单选题Diesel engines obtain combustion air through turbo chargers，blowers，or（）.Aair startersBcarburetorsCnatural aspirationDair receivers
单选题Compared to a naturally aspirated diesel engine, a supercharged diesel engine has（）Aa cylinder air charge of higher pressureBincreased pumping lossesCless valve overlapDreduced blow-by
单选题Proper dispersion of fuel in a diesel engine cylinder is dependent upon the （）Ainjection pressureBshape of combustion spaceCturbulence in combustion spaceDall of the above