单选题If the compression ratio is increased on any diesel engine, （）Athe expansion ratio will decreaseBcombustion will be slowed downCthermal efficiency will decreaseDthermal efficiency will increase
单选题
If the compression ratio is increased on any diesel engine, （）
A
the expansion ratio will decrease
B
combustion will be slowed down
C
thermal efficiency will decrease
D
thermal efficiency will increase
参考解析
解析：
暂无解析
相关考题：
Which of the following reasons represents why the designed compression ratio of a gasoline engine is lower than that of a diesel engine?A.compression must be low for effective spark ignitionB.compression must be low for required horsepower and torque generationC.compression must be low to prevent pre-ignitionD.compression must be low to have effective pre-ignition
Cold weather starting of a diesel engine is more difficult than warm weather starting due toA.use of low viscosity oil in cold weatherB.increased moisture content of inlet air in cold weatherC.increased drag of pistons and bearings due to increased oil viscosityD.higher compression pressures reached due to smaller clearances existing in the engine during cold weather
单选题（）are increasingly used as main engine on merchant vessels, because they have a high Hp/Weight ratio.ASlow speed diesel enginesBMedium-speed diesel enginesCSteam enginesDGasoline engines
单选题The ignition of the fuel in diesel engine is caused by the （） of compression of the air previously admitted into the cylinders.Avacuum pressureBspecific gravityCheatDviscosity
单选题Worn main bearing will cause the compression ratio of an auxiliary diesel engine to（）AincreaseBdecreaseCremain the sameDincrease on compression decrease on expansion
单选题Which of the following operating conditions can occur when shims are removed from the joint between the foot of a marine type diesel engine connecting rod and the bearing box?（）ADecreased connecting rod bearing clearanceBIncreased connecting rod bearing clearanceCDecreased compression ratioDIncreased compression ratio
单选题Which of the listed diesel engine operating conditions should be checked immediately after any diesel engine is started?（）AExhaust temperatureBLube oil levelCLube oil pressureDWater level in the expansion tank
单选题When the normal compression ratio of a diesel engine is not very high, misfiring at light loads may be caused by （）Aoverloading the engineBlow exhaust valve liftCexcessive cylinder coolingDinsufficient mechanical clearance
单选题Cold weather starting of a diesel engine is more difficult than warm weather starting due to（）Ause of low viscosity oil in cold weatherBincreased moisture content of inlet air in cold weatherCincreased drag of pistons and bearings due to increased oil viscosityDhigher compression pressures reached due to smaller clearances existing in the engine during cold weather
单选题Proper atomization of fuel in diesel engine combustion chambers will （）.Aaffect the injection pressureBimprove combustionCreduce compression pressureDdecrease power output
单选题The ratio of the brake horsepower to the indicate of a diesel engine is its （）Athermal efficiencyBmechanical efficiencyCbrake thermal efficiencyDvolumetric efficiency
单选题The arrangement and shape of the cams on a diesel engine camshaft directly control which of the listed groups of operating conditions?（）Aspeed, torque, and horsepower productionBfiring order, valve timing, and valve liftCfuel consumption, efficiency, and cylinder pressureDscavenge pressure, compression ratio, and exhaust pressure
单选题For a given fuel, a change in the compression ratio will affect the ignition lag by which of the listed means?（）AAn increase in compression ratio will increase the ignition lagBAn increase in compression ratio will decrease the ignition lagCA decrease in compression ratio will decrease the ignition lagDA decrease in ignition lag will increase the compression ratio
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Which of the following reasons represents why the designed compression ratio of a gasoline engine is lower than that of a diesel engine?（）Acompression must be low for effective spark ignitionBcompression must be low for required horsepower and torque generationCcompression must be low to prevent pre-ignitionDcompression must be low to have effective pre-ignition
单选题When a diesel engine compression pressure is checked, the indicator is connected to the （）Acylinder exhaust portsBinjection lineCcylinder indicator cockDbanjo oiler line
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Piston compression rings used in a diesel engine function to （）Atransfer heat from the cylinder to the pistonBscrape oil from the sides of the pistonCseal the combustion space from the crankcasesDprevent any piston contact with the cylinder liner
单选题When the load is increased on a turbocharged diesel engine, the amount of increased air supplied by the turbocharger will（）Alag behind the increased fuel supplied to the engineBenter the engine along with the increase in the fuelCenter the engine before the increased fuel supplyDleave the turbocharger as a negative pulse
单选题Which of the following relationships should occur between the temperature developed in a combustion space, and the compression ratio of the engine?（）AHigher compression ratios create higher temperatureBHigher temperatures create higher compression ratiosClow temperatures create higher compression ratiosDHigher compression ratios create low temperatures
单选题If a diesel engines exhaust temperature is abnormally high, the cause could be（）Atoo light of a loadBinjection timing is too earlyCoverloading of the engineDtoo low of a compression ratio
单选题Higher than normal temperature air passing through the intake of a diesel engine will result in（）Agreater overall efficiencyBgreater fuel economyClower horsepowerDlower compression ratio