Lesson-5-Fuel-Oil-System

精品文档 1欢迎下载 Lesson 5 Fuel Oil System 第 5 课 燃油系统 1 Marine engines must operate successfully on heavy residual fuel oils which may vary in quality and analysis depending upon the source of their crude and the refinery processes 1 船用发动机必须能良好地燃用重油运转 这些重油根据原油来源和炼油过程在质量和 成分上是不同的 2 Accurate and complete analysis are difficult to obtain but specifications should confirm that certain parameters are not exceeded Samples of the oil delivered should be kept for reference 2 准确和完整的分析难以获取 但应确认规格中某些参数不超出限定 所供油的油样应 保留 以供参考 3 Density of the oil must be given usually measured at 15 since the consignment will be measured by weight It will also be necessary to know this to adjust centrifuges to give efficient purification 3 由于交货 油 时是用重量来度量的 因此必须给出油的密度 通常为 15 下测得的 知 道油的密度对于调整分油机以便给予高效的净化也是必要的 4 Viscosity is required to calculate temperatures at which the fuel is treated and injected into the engine 4 要求明确豁度 用以计算燃料在处理和喷人发动机时的温度 5 Flash point for the fuel must not be below 60 although the actual value need not be stated This minimum is for safety reasons 5 虽然不必说明实际值 但燃油的闪点绝不能低于60 这个最低值的要求是出于 安 全原因 6 Other factors should also be considered when selecting a fuel oil Among those which affect combustion are the fuel oil s viscosity cetane number and calorific value the sulphur in it and its carbon residues and ash are factors that decide the formation of combustion products and the engine s maintenance has a lot to do with its flash and setting points specific gravity viscosity water content and the mechanical impurities in it 6 在选择燃油时 也应考虑其他因素 其中影响燃烧的因素有燃油豁度 十六烷值和发热 值 硫分 残炭值以及灰分是决定燃烧产物形成的因素 而发动机的保养与燃油的闪点 凝 精品文档 2欢迎下载 点 比重 勃度 含水量和机械杂质含量有很大关系 7 The fuel oil system for a diesel engine can be considered in two parts the fuel supply and the fuel injection systems Fuel supply deals with the provision of the fuel oil suitable for use by the injection system 7 柴油机的燃油系统 见图 5 1 可认为由两部分组成 燃油供给系统和燃油喷射系 统 燃油供给系统用于为燃油喷射系统提供适合其使用的燃油 FuelFuel OilOil SupplySupply 燃油供给燃油供给 8 Fuel to be used is first transferred from storage tanks to a settling tank in which it is heated to allow some water and sludge to settle out by gravity and be drained off The fuel is then passed through the purification system and discharged to a daily tank Settling and service tanks are lagged to conserve heat 8 要用的燃油首先从储油柜驳运到沉淀柜 燃油在沉淀柜中被加热 使一些水和油渣借助 重力沉淀出来并被泄放掉 然后 燃油经过净化系统被排人日用柜 沉淀柜及日用柜通过 外包隔热层来保存热量 9 From the service tanks the treated oil is pumped through a pressurized fuel system to the engine With the oil temperatures necessary for high viscosity fuel and the possibility that a trace of water may still be present it is necessary to maintain the engine pump suctions and circulating connections under pressure to inhibit boiling gasification and cavitation 9 经过处理的油从日用柜泵出 经过加压的燃油系统进人发动机 高勃度燃油需要一定 的油温 而且有可能含有极少量的水分 因此发动机的油泵吸头和循环接口需要保持在一 定的压力下 以防止沸腾 气化和气蚀 10 The oil first passes to the supply pump which raises its pressure to about 4 bar this pressure is maintained in the circulating returns The circulating or booster pump draws oil from the primary discharge raising its pressure to 10 12 bar and delivering it through the heater viscosity regulator and fine filter to the main engine fuel pumps The viscosity regulator controls the fuel oil temperature in order to provide oil at the correct viscosity for combustion 10 燃油首先进人供油泵 油泵将油压提高到约 4 bar 燃油在循环回路中保持这一压力 循环泵或增压泵从供油管吸取油 将油的压力升至 10 一 12 bar 通过加热器 豁度调节 器和细滤器将燃油提供给主机燃油泵 燃油勃度调节器控制燃油温度 提供合适豁度的 燃油以供燃烧 11 In large two stroke engines the fuel injection will circulate fuel during the periods they are not actually injecting it to the cylinder This ensures that the system remains fully primed and at 精品文档 3欢迎下载 uniform temperature The circulated oil is returned to a buffer or venting tank from which it passes either back to the low pressure part of the system before the circulating pump suction or into the service tank 11 在大型二冲程柴油机上 喷油器在不喷射燃油期间会循环燃油 这就确保了在输送系统 内保持注满燃油 温度一致 被循环的燃油回到缓冲柜或放气柜 再从这里回到循环泵吸 人口之前的系统低压部分 或者回到日用柜 12 Various safety devices must be included in the system with alarms to detect loss in oil pressure low tank level etc Quick closing valves which can be operated from outside the machinery space must be fitted to all tanks and to the main inlet to the engine Fuel pumps must have remote switches by which they can be stopped in an emergency 12 系统内还包括各种安全装置 带有警报器 可以探测到油压损失 低油位等故障 所有 的油柜和柴油机的主进油口都必须装配能在机舱外操纵的速闭阀 燃油泵必须有遥控开关 可以在紧急情况下停泵 Fuel Injection 燃油喷射系统 13 The function of the fuel injection system is to provide the amount of fuel at the right moment and in a suitable condition for the combustion process That means the fuel injection system for diesel engines must be able to supply a metered amount of fuel to each cylinder for each power stroke according to the load on the engine and must include a timing mechanism to ensure that delivery of this fuel commences at the correct moment and must have a means to atomize the fuel 喷油系统的功用是在适当的时刻 以适当的状态 为燃烧过程提供一定量的燃油 这就意 精品文档 4欢迎下载 味着 柴油机的喷射系统必须能根据柴油机的负载为每一件功行程向各缸提供适量的燃油 还必须包括一个定时机构以确保在适当的时刻开始供油 而且还必须采取措施使燃油雾化 14 The type of injection system most commonly used in modern diesel engines is the jerk pump system In the system a separate injection pump is provided for each cylinder which operates once every cycle The barrel and plunger together with the cam are dimensioned to displace fuel at the rate it is required in the combustion chamber Ports in the barrel in combination with slots in the plunger determine the amount of fuel delivered and the timing of its entry to the cylinder Each pump is connected to the injector or injectors serving one cylinder These injectors have spring loaded needle valves which are set to ensure that the fuel is raised to a sufficiently high pressure to cause atomization when they automatically open to admit it to the cylinder 现代柴油机广泛使用的是独立喷射系统 在该系统中 各缸有一个喷射泵 每循环喷油一 次 柱塞和套筒连同凸轮一起设计加工成按燃烧室需要的供油速率提供燃油 套筒上的油 口和柱塞上的槽及独立的机械操纵的溢油阀配合 决定供油量及喷入气缸的时刻 每个喷 油泵连一个或多个为一缸所用的喷油器 这些喷油器带弹簧加力的差动针阀 针阀调整到 燃油升压至足够高时自动开启以确保其喷入气缸时雾化 15 The engine is also provided with a governor which is designed to regulate the engine s speed by adjusting the quantity of oil injected When the engine runs at a speed higher or lower than is set the governor will act automatically and reduce or increase the fuel oil supply so that the engine speed can be adjusted The flyweight type governor with an adjustable spring is one of those most commonly used for large marine engines The regulating movements of the flyweights are transmitted to the fuel pump regulating rods by means of a built in servomotor The oil pressure necessary for operating this governor is delivered by a gear type oil pump built into the governor 15 柴油机还配有调速器 调速器的设计是通过调节喷油量来调节柴油机的转速 当柴 油机转速高于或低于设定值时 调速器会自动作用 减少或增加供油量以调节柴油机转速 带有可调弹簧的飞重式调速器是大型船用柴油机最常用的调速器之一 飞重的调节运动通 过内装的伺服马达传递到燃油泵调节杆 操作调速器所需的油压由一台内装在调速器上的 齿轮型油泵提供 CombustionCombustion ofof FuelFuel 燃油的燃烧燃油的燃烧 16 The general indications of good combustion are similar in any operating diesel engine a clear exhaust power produced and exhaust temperatures normal for the throttle setting There should be no uneven running knocking from cylinders or the fuel system 16 良好燃烧的一般迹象对任何运转中的柴油机都是相似的 排气透明 对应一定的节流 调定所产生的功率和排气温度正常 不应有不匀转动 气缸或燃油系统不应有敲击声 精品文档 5欢迎下载 17 Viscosity or resistance to flow in a fuel oil is important when considering combustion It must be low enough to ensure correct atomization at the fuel injector Since viscosity reduces as temperature is increased it will be necessary to heat heavy fuel oil to reduce its viscosity to about 15 cSt at 50 C before atomization for combustion 17 在考虑燃烧时 燃油的豁度或流动阻力很重要 豁度必须足够低才能确保燃油在喷油器 的良好雾化 由于豁度随油温升高而降低 因此在燃烧雾化前有必要加热重油降低豁度 达到 50 下约 15 cSto s 18 Atomization is the splitting up of the fuel into very small droplets by the fuel injector forcing fuel at high pressure through small atomizer holes 18 雾化是由喷油器迫使燃油在高压下通过雾化器的小孔 而将燃油分裂成很小的油滴 19 Penetration refers to the distance the oil droplets travel into the combustion space before mixing with the air and igniting This will depend upon droplet size atomization velocity leaving the injector and the conditions within the combustion chamber 19 穿透距离指油滴进人燃烧室在与空气混合并发火之前所经过的距离 这取决于油滴的大 小 雾化 离开喷油器的速度以及燃烧室内的状况 20 Turbulence is the movement of compressed air and fuel within the combustion space before combustion occurs Turbulence will improve the mixing of fuel and air for effective and rapid combustion 20 扰动是燃烧发生前压缩空气和燃油在燃烧室内的运动 扰动会促进燃油和空气的混合 以产生迅速有效的燃烧 B Multiple Choice B 选择题 Questions 1 4 are based on paragraphs 1 7 根据课文第 1 7 段回答问题 1 4 1 Which factor of the following affects not only the fuel s combustion but also the engine s maintenance 以下哪个因素既影响燃油的燃烧又影响发动机的保养 答案 C A The cetane number 十六烷值 B The flash point 闪点 C The viscosity 黏度 D The setting point 凝点 2 The fuel oil system for a diesel engine can be considered in two parts he fuel supply and the systems 柴油机的燃油系统包括燃油供给系统和 系统两部分 答案 D A fuel purification燃油净化 B fuel combustion燃油燃烧 C fuel treatment燃油处理 D fuel injection燃油喷射 精品文档 6欢迎下载 3 Which factor of the following affects the fuel s combustion 下列 哪个因素影响燃油的燃烧 答案 C A The setting point凝点 B The flash point 闪点 C The cetane number 十六烷值 D The mechanical impurities 机械杂质 4 Which factor of the following affects the engine s maintenance 下列哪个因素影响发动机的保养 答案 D A The calorific value 发热值 B The sulphur 硫分 C The cetane number十六烷值 D The setting point 凝点 Questions 5 9 are based on paragraphs 8 15 根据课文第 8 15 段回答问题 5 9 5 Fuel to be used is first transferred from storage tanks to a in which it is heated to allow some water and sludge to settle out by gravity and be drained off 要用的燃油首先从储油柜驳运到 在这里燃油被加热 使一些水和油渣借助重力沉淀出来 并被泄放掉 答案 B A service tank 日用油柜 B settling tank沉淀柜 C buffer tank 缓冲柜 D slop tank污油水柜 6 Settling and service tanks are to conserve heat 沉淀柜及日用柜 来保存热量 答案 C A tagged 加标签于 B labeled贴标签于 C lagged给 加上外套 本题中译为 外包隔热层 D tapped轻敲 7The viscosity regulator controls the in order to provide oil at the correct viscosity for combustion 黏度调节器控制 提供合适豁度的燃油以供燃烧 答案 C A engine s speed 发动机速度 B engine s load 发动机负载 C fuel oil temperature燃油温度 D fuel oil flow 油流 8 Quick closing valves which can be operated from must be fitted to all tanks and to the main inlet to the engine 所有的油柜和柴 油机的主进油口都必须装配能在操纵的速闭阀 答案 A A outside the machinery space机舱外 精品文档 7欢迎下载 B only within the machinery space只有在机舱内 C only w i thin the main control room只有在主控制室内 D none of the above 以上都不是 9 The engine is also provided with which is designed to regulate the engine s speed by adjusting the quantity of oil injected 柴油机还配有 其设计是通过调节喷油量来调节主机转速 答案 A A a governor调速器 B a servomotor伺服马达 C a pump泵 D an injector喷油器 10 The general indications of good combustion are similar in any operating diesel engine a an exhaust power produced and exhaust temperatures normal for the throttle setting 良好燃烧的一般迹象对任何运转中的柴油机都是相似的 排气是 对应一定的节流调定所 产生的功率和排气温度正常 答案 D A smoky 多烟的 B grey灰色的 C light blue淡蓝色 D clear透明的 11 is the splitting up of the fuel into very small droplets by the fuel injector forcing fuel at high pressure through small atomizer holes 是由喷油器迫使燃油在高压下通过雾化器的小孔 而将燃油分裂成很小的油滴 答案 B A Turbulence 扰动 B Atomization 雾化 C Penetration 穿透距离 D Performance运转情况 12 or resistance to flow in a fuel oil is important when considering combustion 在考虑到燃烧时 油的 或流动阻力很重要 答案 A A Viscosity 勃度 B Density密度 C Cetene number十六烷值 D Calorific value发热值 13 is the movement of compressed air and fuel within the combustion space the mixing of fuel and air for effective and before combustion occurs It will improve rapid combustion 是燃烧发生前压缩空气和燃油在燃烧室内的运动 它会促进燃油与空气的混合 以产生迅 速有效的燃烧 答案 A A Turbulence雾化 B Atomization扰动 C Penetration 穿透距离 精品文档 8欢迎下载 D Performance运转情况 14 refers to the distance the oil droplets travel into the combustion space before mixing with the air and igniting 指油滴进人燃烧室在与空气混合并发火之前所经过的距离 答案 C A Turbulence 雾化 B Atomization扰动 C Penetration透距离 D Performance运转情况 Task 2 Vocabulary and Structure 任务 2 词汇与结构 A Technical TermsA 专业术语 Translate the following into Chinese 将下列词组译成汉语 1 燃油喷射系统 2 储油柜 3 沉淀柜 4 戮度调节器 5 针闷 6 定时机构 7 速闭阀 8 增压泵 1 fuel injection system 2 storage tank 3 settling tank 4 viscosity regulator 5 needle valve 6 timing mechanism 7 quick closing valve 8 booster pump B Active WordsB 常用词 Complete the following sentences by filling in the blanks with the words in the table Change the form of the words if necessary 从框中选词完成句子 如有必要改变词的形式 dimension throttlelagsplitcalculateaffectdischarge 1 The fuel is then passed through the purification s