单选题Distortion of the spray pattern of a nozzle or injector may be indicated by a/an（）Ahigh firing pressureBoverload of that particular cylinderCsmoky exhaustDcooling water temperature rise
单选题
Distortion of the spray pattern of a nozzle or injector may be indicated by a/an（）
A
high firing pressure
B
overload of that particular cylinder
C
smoky exhaust
D
cooling water temperature rise
参考解析
解析：
暂无解析
相关考题：
One advantage of the all-purpose nozzle is that it ______.A.can fit any size hoseB.converts a stream of water into a fogC.increases the amount of water reaching the fireD.can spray two streams of water at the same time
Indirect cooling of fuel injector nozzle holders for diesel engines is accomplished primarily byA.heat conduction into the injected fuel oilB.heat conduction into the water jacket wallC.water circulation through passages in the holderD.fuel oil circulation through passages m the holder
第一组Older loop scavenged engines may have a single injector mounted centrally in the cylinder head. Because the exhaust valve is in the center of the cylinder head on modern uniflow scavenged engines the fuel valves (2 or 3) are arranged around the periphery of the head. The pressure at which the injector operates can be adjusted by adjusting the loading on the spring. The pressures at which the injectors operate vary depending on the engine, but can be as high as 540 bar. Some injectors have internal cooling passages in them extending into the nozzle through which cooling water is circulated. This is to prevent overheating and burning of the nozzle tip. Injectors on modern engines do not have internal cooling passages. They are cooled by a combination of the intensive bore cooling in the cylinder head being close to the valve pockets and by the fuel which is re-circulated through the injector when the follower is on the base of the cam or when the engine is stopped. As well as cooling the injector, re-circulating the fuel when the engine is stopped keeps the fuel at the correct viscosity for injection by preventing it from cooling down. Fuel injectors must be kept in good condition to maintain optimum efficiency, and to prevent conditions arising which could lead to damage within the cylinder. Injectors should be changed in line with manufacturers recommendations, overhauled and tested. Springs can weaken with repeated operation leading to the injector opening at a lower pressure than designed. The needle valve and seat can wear which together with worn nozzle holes will lead to incorrect atomization and dribbling.Modern uniflow scavenged engines have______.A.a single injector mounted in the center of the cylinder headB.several injectors mounted around the external boundary of the cylinder headC.a single injector mounted at the external boundary of the cylinder headD.several injectors mounted in the center of the cylinder head
Springs in fuel injectors will become not strong enough to work because______.A.the injector opens at a lower pressure than designedB.the needle valve and seat wear outC.the nozzle holes wear outD.long time in use
_______can be a direct cause of faulty operation of diesel engine fuel injection nozzles.A.Excessive fuel nozzle holder coolingB.Sediment in the fuel supplyC.Distortion of the fuel spray patternD.Improper atomization of the fuel
An increase in the fuel injection pump discharge pressure can be caused by a/an _______.A.leaking delivery valveB.excessive bearing end playC.plugged injector spray holeD.increased plunger stroke
The difference in water spray pattern between the high-velocity tip and low-velocity applicator used with the all-purpose nozzle is due to ______.A.a difference in water pressureB.the method of breaking up the water streamC.the length of the applicatorD.All of the above
If not attached to the nozzle, each low-velocity spray applicator on a vessel must be stowed__________.A.in a protected area on the main deckB.inside a machinery space near the entranceC.next to the fire hydrant to which the fire hose is attachedD.on a rack inside the quarters near the entrance
单选题In a jerk pump, the amount of fuel that will be forced through the spray nozzle on each upward stroke of the plunger depends on （）Athe pump supply pressureBthe slope of the fuel camChow the plunger is rotatedDthe number of sleeve segments engaged with the rack
单选题As the plunger moves up, the ports are closed and the fuel （） and delivered to the injector nozzle at very high pressure.Abeing compressedBto be pumped upCis pressurizedDare built up
单选题One advantage of the all-purpose nozzle is that it（）.Acan fit any size hoseBconverts a stream of water into a fogCincreases the amount of water reaching the fireDcan spray two streams of water at the same time
单选题The all-purpose nozzle will produce a fog spray when you（）.Apull the nozzle handle all the way back toward the operatorBpull the nozzle handle back to a position where the handle is perpendicular to the plane of the nozzleCpush the nozzle handle forward as far as it will goDinsert a fog applicator between the fire hose and nozzle
单选题In the common rail system, excessive pressure in the header may be caused by （）Aimproper adjustment of the bypass valveBa dribble in the fuel injection nozzleCinsufficient leak-off through injection nozzle packingDa malfunctioning injection nozzle
单选题Diesel engine exhaust temperatures may be used to indicate （）.Aleaking exhaust valvesBan overloaded cylinderCa clogged injector nozzleDall of the above
单选题In a unit injector the amount of fuel that will be forced through the spray nozzle on each stroke of the plunger depends on （）Athe pump supply pressureBthe slope of the fuel camChow the plunger is rotatedDthe number of sleeve segments engaged with the rack
单选题The difference in water spray pattern between the high-velocity tip and low-velocity applicator used with the all-purpose nozzle is due to（）.Aa difference in water pressureBthe method of breaking up the water streamCthe length of the applicatorDAll of the above
单选题Which of the following problems may occur if the opening pressure of a fuel injection nozzle is greater than specified by the engine manufacturer?（）AThe amount of fuel injected will be increasedBThe start of injection will be retardedCThe nozzle will permit fuel to dribbleDThe spray pattern will be distorted
单选题Indirect cooling of fuel injector nozzle holders for diesel engines is accomplished primarily by （）.Aheat conduction into the injected fuel oilBheat conduction into the water jacket wallCwater circulation through passages in the holderDfuel oil circulation through passages in the holder
单选题A defective injector nozzle in a propulsion diesel engine can cause（）Aengine power lossesBsmoking due to unburned fuelChigh exhaust temperature readingsDall of the above
单选题A distorted spray pattern from a fuel injector can cause a diesel engine to have （）Ahigher firing pressureBmore power outputClower fuel pressureDless power output
单选题Faulty operation of diesel engine fuel injection nozzles can be a direct cause of（）.Aexcessive fuel nozzle holder coolingBsediment in the fuel supplyCdistortion of the fuel spray patternDimproper atomization of the fuel
单选题Faulty operation of diesel engine fuel injection nozzles can be directly caused by （）.Awater in the fuel oil supplyBexcessive fuel nozzle holder coolingCa distorted fuel spray patternDleakage past the plunger into the oil drain
单选题An increase in the fuel injection pump discharge pressure can be caused by a/an （）Aleaking delivery valveBexcessive bearing end playCplugged injector spray holeDincreased plunger stroke
单选题If a few injector spray holes become plugged, the result could be （）Aexcessive surging at governed speedBcombustion knock under loadCpoor fuel combustionDall of the above
单选题A fire main system must have enough fire hydrants so that each accessible space may be sprayed with（）.Aa low velocity spray applicatorBa water spray or solid streamCat least two spray patterns of waterDat least 25 psi delivered pressure
单选题If not attached to the nozzle,each low-velocity spray applicator on a vessel must be stowed（）.Ain a protected area on the main deckBinside a machinery space near the entranceCnext to the fire hydrant to which the fire hose is attachedDon a rack inside the quarters near the entrance
单选题The 12-foot low-velocity fog applicator（）.Ahas a spray pattern 12 feet in diameterBcan be used in conjunction with both 1-1/2 inch and 2-1/2 inch all-purpose nozzlesChas a 90°bend at its discharge endDhas a screw thread end which connects to the all-purpose nozzle