单选题Injectors for use with heavy fuel oil must be cooled by either water or light oil to （）Aprevent heat corrosion to internal componentsBincrease fuel delivery rate and economyCprevent pre-ignitionDavoid carbonization of the nozzle tips
单选题
Injectors for use with heavy fuel oil must be cooled by either water or light oil to （）
A
prevent heat corrosion to internal components
B
increase fuel delivery rate and economy
C
prevent pre-ignition
D
avoid carbonization of the nozzle tips
参考解析
解析：
暂无解析
相关考题：
For the fuel oil purifier higher throughput and more efficient process can be achieved if the fuel is0 A.viscosity a heated to reduce itsB.cooled to reduce its temperatureC.heated to reduce its densityD.heated to reduce its gravity
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
Injectors for use with heavy fuel oil must be cooled by either water or light oil to_____.A.prevent heat corrosion to internal componentsB.increase fuel delivery rate and economyC.prevent pre-ignitionD.avoid carbonization of the nozzle tips
A ship which is required to carry an Oil Record Book must log in the book ______.A.discharge of ballast or cleaning water from fuel tanksB.sounding levels of all fuel tanks on a daily basisC.the grade and specific gravity of all fuel oil carriedD.fuel consumption rates on a weekly basis
单选题When the ship is going to enter into the harbor,（）Achange from heavy fuel oil to diesel oil for mail engineBpumping oil bilge waterCchange sea chest form high level one to lower oneDtest emergency generator
单选题Maintaining the close tolerances in diesel fuel pumps and injectors requires the use of（）.Afuel/water separatorsBday tanksCinjector test standDfuel filters
单选题When centrifuging heavy fuel oil, an important factor to consider is the （） (1) flow rate (2) viscosity of the fuel oilA(1) only is correctB(2) only is correctCboth (1) and (2) are correctDneither (1) or (2) are correct
单选题A viscosity regulator used for an engine is usually provided in order to （） for an engine burning heavy fuel oil.Aregulate the fuel supplyBmaintain a constant fuel viscosity at the fuel valvesCmaintain efficient coolingDalter the fuel density
单选题A ship which is required to carry an Oil Record Book must log in the book（）.Adischarge of ballast or cleaning water from fuel tanksBsounding levels of all fuel tanks on a daily basisCthe grade and specific gravity of all fuel oil carriedDfuel consumption rates on a weekly basis
单选题In motor-ships, （）, after passing through main and motion bearings and oil cooled pistons, etcis either retained in the bedplate.Athe fuel oilBthe lubricating oilCthe refrigerating oilDthe hydraulic oil
单选题When preparing a ship for heavy weather，fuel oil day tanks should be（）.Apumped overboard to calm the seasBdrained to the lower hull to reduce free surfacesCfilled to ensure that sufficient fuel oil is available during a lengthy emergencyDpartially drained to increase free surfaces in order to reduce motions
单选题What color exhaust will be exhibited when a slow speed two-stroke/cycle main propulsion diesel engine, designed to operate on light and heavy fuel oil, is operated on insufficiently preheated heavy fuel oil?（）AWhiteBBlackCBlueDClear
单选题The pollution prevention regulations do not apply to the transfer or discharge of （）Abunker fuel for use aboard shipBlubricating oil for use aboard shipCcoconut oil carried in tank vesselsDoily water from a ships bilges
单选题Main engines as well as auxiliary engines operating on heavy fuel should have continuous on the lubricating oil, either according to the bypass or batch principles（）AfilteringBcentrifugingCdepositingDoperating
单选题The safe rate of bunkering heavy fuel oil is directly related to the （）.Atype of fuel transfer pump aboardBtemperature of the fuel oil being receivedCsize of the fuel storage tanks ashoreDdistance from the fuel oil storage tanks ashore
单选题Machinery driving fuel oil transfer and fuel oil service pumps must be fitted with a remote means of stopping the machinery from （）.Awithin the space concernedBoutside the space concernedCthe throttle stationDwithin the fire room
单选题Proper filtering and straining of diesel fuel is important because the（）Afuel oil pump will over-speed if dirt is not removedBfuel oil transfer pumps cannot tolerate small amounts of grit in the oilCfuel injectors may be damaged by foreign particles in the fuel oil dirtyDfuel will clog the intake air filter
单选题Differential needle valves used in fuel injectors are directly closed by（）Acam actionBspring forceCfuel oil pressureDfiring pressure
单选题The soot blowers are operating in the oil fuel boiler the air/fuel ratio must （） throughout the action, and blowers greased after use.Abe increasedBbe decreasedCremain constantDeither be increased or remain constant
单选题On engines having oil cooled pistons the lubricating oil pre-heater must be put into operation and the rate of heating so （） that the temperature of the piston cooling oil returns are 32℃ to 35℃ over a period of at least two hours.AslowBquickCarrangedDhigh
单选题Injectors on modern engines are cooled by a combination of the intensive bore cooling in the cylinder by a combination of the intensive bore pockets and by the fuel which is re-circulated through the injector when the follower is on the （）of the cam or when the engine is stopped.AslopeBbaseCtopDbottom
单选题Heavy soot accumulations in an auxiliary boiler could be caused by（）Awater in the fuel oilBexcessive cyclingChigh fuel oil pressureDimproper burner maintenance
单选题Fuel injectors used in heavy fuel oil systems are usually provided with cooling to reduce（）.Acold corrosion of the nozzlesBfuel viscosity for better atomizationCcarbon accumulation on the nozzlesDfuel detonation in the cylinders
单选题The temperature of the fuel oil received during bunkering operations is critical in determining the（）Aexpansion space to leave in a tankBflash point at which the fuel will burnCtemperature to which the fuel must be heatedDrate at which the fuel can be pumped during transfer operations
单选题Proper filtering and straining of fuel oil is important because the （）.Afuel oil pump will over-speed if dirt is not removedBfuel oil transfer pumps cannot tolerate small amounts of dirt in the oilCfuel injectors may be damaged by foreign particles in the fuel oilDdirty fuel will clog the intake air filter
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