单选题A diesel engine should not be operated at low loads for long periods of time because（）Aheavy carbon deposits will buildup on the valves and in the exhaustBfuel dilution is increased at low loadCexhaust valves may be damagedDall of the above
单选题
A diesel engine should not be operated at low loads for long periods of time because（）
A
heavy carbon deposits will buildup on the valves and in the exhaust
B
fuel dilution is increased at low load
C
exhaust valves may be damaged
D
all of the above
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
A diesel engine exposed to widely varying ambient temperatures should use to a lubricating oil with .A.a high viscosity indexB.a low viscosity indexC.neutralize acidsD.resist oxidation at high temperatures
单选题As a heat engine,（） energy is the source of power by which the diesel engine can be operated.AelectricBheatCmechanicalDexhaust
单选题The purpose of the compensating adjustment used in a diesel engine hydraulic governor is to （）Acompensate for low oil levelBincrease governor promptnessCprevent governor huntingDlimit engine load
单选题An over-speed trip stops a diesel engine when the engine （）Aruns out of fuelBhas low lubricating oil pressureCexceeds a set maximum speedDhas high cooling water temperature
单选题The diesel engine exhaust gas bypass, as fitted with some waste heat boilers, is installed to （）Aprevent engine back pressure at heavy loadsBincrease total engine efficiency at low loadsCprevent boiler corrosion at low engine loadsDimprove engine fuel consumption at any load
单选题Starting a large low-speed propulsion diesel engine on diesel fuel during cold weather conditions, will be made easier by （）Aincreasing the quantity of starting airBincreasing the lube oil pressureCheating the engine fuel supplyDheating the engine coolant
单选题The highest loads applied to the diesel engine crankshaft main bearings are （）Aaxial loadsBfiring loadsCinertia loadsDcentripetal loads
单选题Which of the following procedures should be carried out when a large, low-speed, diesel engine is operated with one cylinder secured?（）ALubrication to the defective cylinder should be increasedBCooling water temperature to the engine should be increasedCOnly the turbocharger speed should be reducedDEngine speed should be reduced
单选题In order to start a large, low-speed, main propulsion diesel engine on high viscosity fuel after an extended shutdown, the （）Afuel must be preheatedBintake air should be preheatedClube oil outlet temperature should be increased 20℃ above normalDnone of the above
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Low compression of diesel engine may result from （）Aa worn cylinderBbroken piston ringsCany of A and BDnone of the above
单选题A diesel engine exposed to widely varying ambient temperatures should use to a lubricating oil with （）Aa high viscosity indexBa low viscosity indexCneutralize acidsDresist oxidation at high temperatures
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Burning fuel with a high sulfur content in a diesel engine will （）Aincrease thermal efficiencyBcause clogging of the fuel systemCincrease the ability of the engine to start in cold weatherDproduce corrosion in the cylinder and exhaust system at low loads
单选题A diesel engine should not be operated at low loads for long periods of time because（）Aheavy carbon deposits will buildup on the valves and in the exhaustBfuel dilution is increased at low loadCexhaust valves may be damagedDall of the above
单选题What harmful condition can result if a diesel engine is operated at very light loads for long periods of time?（）Aincreased carbon buildupBburning of intake valvesCexcessive firing pressuresDincreased fuel consumption
单选题Electrically operated safety devices on auxiliary diesel engines function to stop the engine by （）.Aincreasing the volume of intake airBshutting off the fuel supplyCincreasing the engine back pressureDover-speeding the engine
单选题A diesel engine may be hard to start if the （）Aair intake is restrictedBengine is cranked too fastCvibration dampener is faultyDexhaust back pressure is low
单选题Operating a diesel engine under light loads and at low temperatures for an exhaust for an extended period can result in（）Aformation of carbon on the intake and exhaust portsBhigh water jacket temperaturesCoverheated pistons and cylindersDan increase in lube oil viscosity due to fuel dilution
单选题If it becomes necessary to cutout an individual cylinder of a large, low-speed, main propulsion diesel engine, the fuel to that cylinder should be secured and its （）Afuel pump should be removed and all connections blanked offBcylinder oil feed rate should be increased slightly above that used at normal sea speedCcylinder oil feed rate should be reducedDcylinder oil feed rate should be increased to the maximum flow capable of the metering pump
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According to the relevant regulation, lifeboat should be powered by（）.Ainboard diesel engineBoutboard diesel engineCoutboard gasoline engineDinboard gasoline engine
单选题Which is false about engine trials?（）Aengine trails should be done after finishing the operation of turning the engine with the turning gear and starting the engine on air brieflyBin the operation of engine trails, the main engine should be running in low-speedCAs to the ship equipment with twin main engine, engine trials should be done with one engine ahead and another engine astern at the same timeDthe order “engine trials” should be given by the bridge
单选题When running a large, low-speed, main propulsion diesel engine on heavy fuel, which of the following precautions should be observed when switching back over to diesel oil?（）AThe diesel oil must never be allowed to mix with the heavy fuelBThe temperature of the fuel from the pre–heater should be gradually reduced after switching over the three–way valveCThe heating steam to the pre-heater should be secured as soon as the diesel fuel passes through the three-way valveDThe heating steam must be secured before the diesel oil passes through the three-way valve
单选题When ship navigating in rough sea, the correct operation is （）Anavigating with a low diesel engine speedBnavigating with a stable diesel engine speedCincreasing the efficiency of propellerDincreasing fuel injection
单选题Misfiring in a diesel engine at light loads can be caused by（）Ahigh lube oil temperatureBlow lube oil temperatureCexcessive cylinder coolingDhigh air injection pressure
单选题Which of the following conditions may need to be reduced when operating a large, low speed, main propulsion, diesel engine at low loads?（）AInjection pressuresBControl air supply pressureCCooling water flow through after-coolersDLube oil temperature