If the engine does start on air, but combustion does not immediately begin, the cause may be _____.A.failure of the fuel pumpsB.starting air pressure too lowC.stop valve in air line closedD.the turning gear still engaged
If the engine does start on air, but combustion does not immediately begin, the cause may be _____.
A.failure of the fuel pumps
B.starting air pressure too low
C.stop valve in air line closed
D.the turning gear still engaged
相关考题：
According to the anti -railway group, all the followings are true but ______.A) tunnels are dangerous to public healthB) the noise and the glare of the engine fire may affect people' s nervesC) the rapid speed through the air does damage to people's lungsD) to those with high blood - pressure, the rapid speed of the train causes them to die
If the engine does not start on air, it may be due toA.low compression of the fuel pumpsB.incorrect timing of fuel pumpsC.the starting air valves stuckD.air-locks in fuel oil pipeline
第二组Under normal operation, some lubrication oil mist may be discharged from the air compressor to the air start system. This oil may be from excess compressor cylinder lubrication, from faulty oil scraper rings, or may even be suspended oil vapor contaminating the engine room atmosphere and drawn in at the compressor suction. Oil discharge is kept to a minimum by draining the after cooler, air receiver and starting system. If small quantities of lubrication oil do get passed into the starting air system, they will deposit as thin moist film over internal pipe surfaces but are not readily combustible. If a cylinder non-return valve leak while the engine is in operation, some hot gas, possibly with unburned fuel and cylinder lubrication oil, may be blown through the valve to the adjacent air manifold. With further heating from the leaky valve, this, together with the already deposited oil film, will carbonize and form. incandescent carbon. If starting air is applied to the system while still hot, the high pressure air coming into contact with the burning carbon may cause an explosion. Such an explosion will cause a flame to pass back through the air start pipe system, evaporating the deposited oil film and igniting it in the presence of air. Very high velocities and shockwaves are generated which may rupture pipes and fittings.Alternatively, if excessive oil has entered the air start system, a mixture of air and oil droplets may be discharged through the open cylinder non-return valve during starting. This spray may ignite due to high temperatures in the cylinder, causing a flame through the still open valve to the air manifold.To prevent an explosion, air start valves must be correctly maintained and lubricated to ensure correct timing and free movement with positive closing. Oil in the system must be kept to a minimum, pipe lines must be drained and cleaned internally when necessary and oil discharge from air compressors must be kept to a minimum by good maintenance.The passage is mainly aboutA.crankcase explosionB.scavenge box fireC.starting air pipeD.the danger of explosion in the starting air system
If a diesel engine turned over freely but failed to start, the cause could be ________.A.water in the fuelB.cold lube oilC.excessive starting air pressureD.excessive fuel pressure
One cylinder of a diesel engine is persistently knocking and does not cease(停止) when the fuel supply to that cylinder is secured.Which of the following problems may be the cause?A.Low loading of the cylinderB.Excessive cooling of that pistonC.Sluggish ring action on the pistonD.A mechanical defect in a working part
How does combustion air enter the cylinder of a two-cycle diesel engine ? Through _______．A.Cylinder head valvesB.PortsC.Turbo chargersD.Bleeder valves
If headaches only occur at night,lack of fresh air is often the cause.A:start B:begin C:happen D:visit
单选题If a diesel engine turned over freely but failed to start, the cause could be （）Awater in the fuelBcold lube oilCexcessive starting air pressureDexcessive fuel pressure
单选题Black smoke exhausting from an operating diesel engine is an indication of poor combustion which may be caused by （）Awater in the fuelBinsufficient fuel for combustionCclogged air intake passagesDburning lubricating oil
单选题Which of the following may cause that an engine doesnt turn on starting air?（）Atoo low starting air pressureBmain starting valve closedCneither A nor BDA and B
单选题White smoke exhausting from an operating diesel engine may indicate （）.Aa cracked linerBburning lube oilCan overloaded engineDinsufficient combustion air
单选题Which of the following may lead to the engine NOT to start on air?（）Astarting air pressure too highBcorrect timing of starting air valvesCthree of the six starting valves stuckDthe turning gear disengaged
单选题Which cause of the following can lead to the engine not to start on air?（）Astarting air pressure too highBcorrect timing of starting air valvesCthree of the starting valves stuckDthe turning gear disengaged
单选题A diesel engine may fail to start due to （）Alow air charge temperatureBhigh cranking speedCexcessive fuel dilution of lube oilDhigh compression pressure
单选题The burning of the fuel adds more heat to the air charge, causing it to expand and force the engine piston to do work on the crankshaftWhat does “it” mean in this sentence?（）Athe burningBthe fuelCthe air chargeDthe engine piston
单选题For a fire to begin there must be present a combustible material, oxygen or air to （）combustion, and a source of heat at a temperature high enough to start combustion.AbeginBsupportClastDextinguish
单选题If the electric motor driving an air compressor fails to start, the cause may be a （）.Aleaking unloaderBtripped circuit breakerCcontrol line leakDdefective pop valve
单选题Which of the following may cause that an engine doesnt run on starting air?（）Atoo low starting air pressureBmain start valve closedCneither A nor BDA and B
单选题If the engine does start on air, but combustion does not immediately begin, the cause may not be （）.Alow compressionBfailure of the fuel pump to discharge fuelCincorrect timing of fuel pumpDturning gear being still on
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If the engine does not start on air, it may be due to （）Alow compression of the fuel pumpsBincorrect timing of fuel pumpsCthe starting air valves stuckDair-locks in fuel oil pipeline
单选题How does combustion air enter the cylinder of a two-cycle diesel engine?（）ACylinder head valvesBPortsCTurbo chargersDBleeder valves
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If the engine of a survival craft does not start，check to see（）.Athat the fuel valve is openBif the air supply system is openCif the water sprinkler system is openDif the limit switch is on
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