数据、信息、知识、智慧
知识管理始终受到人们的关注。然而，当我进入这一领域后立刻发现，对于知识、数据、信息和智慧并没有一个准确的定义。下面是我对数据、信息、知识和智慧的理解。
按照研究组织变化方面的系统理论家和学者只.阿克奥夫的观点，他认为人的意识可以分成 5类：
●数据:符号；
●信息:经过加工的有用信息，回答关于“谁”、“什么”和“何
时”的问题；
●知识：数据和信息的运甩回答“如何”的问题；
●理解:回答“为什么”的问题；
●智慧:有价值、可以理解。
阿克奥夫认为，前4类与过去有关;它们是对过去的认知。仅有第5类一智慧一是与未来有关的，因为它融入了想象与设计。拥有智慧，人们就能够创造未来，而不是仅仅掌握过去和现在。但是要拥有智慧并不是一件容易的事，人们还必须具有对其他事物的认识。阿克奥夫给出了更多的解释。
数据:数据未经过加工。它以简单形式存在，如果没有平台的支撑就没有任何意义。它能够以任何形式存在，可以是有用的，也可以是无用的。它的自身没有任何意义。
信息:信息是通过某种关联而具有含义的数据。这个“含义”可能是有用的，也可能是无用的。用计算机语言表述就是由数据组成的关联
数据库。
知识:知识是经过选择的信息，具有一定的目的性。知识有明确的作用。当人们“记忆”信息时，实际上是在积累知识。这种知识对于他们来说是有用的，但不是为了某种目的，其中可能含有更多的知识。例如，小学生可以告诉你“ 2*2=4”，因为他们积累了相关知识丨乘法口诀）。但是对于1267*300”，他们就无法计算了，因为没有相关的乘法口诀。如果要作出这道数学题，需要学习下一步的知识，需要认知和分析能力。用计算机术语表达就是，应用软件用于存储知识。
理解:理解是一个或然的过程。它是经过认知和分析的。通过这个过程，人们可以通过以前掌握的知识获得进一步的知识和整合出新的知识。理解与知识的不同表现为“学问”与“记忆”的差别。有理解力的人能够采取有意识的行动，因为他们能够通过以前的理解整合出新的知识，至少是新的信息。也就是说，理解建立在已有信息、知识和对知识的理解的基础之上。用计算机语言表述就是，人工智能系统具有理解功能，它能够利用所存储的信息和知识整合成新的知识。
智慧:智慧是一种推断和非确定、非或然的过程。它调动了所有的意识，尤其是人所具有的特殊的意识，如道德和伦理规范等。它使人们理解以前未曾理解的东西，以此来达到超越理解本身的目的。它是一种基本的哲学探索。与前4种类型不同，智慧回答关于没有答案或者不能轻易得出答案的问题。在某种意义上说，也可能是处于未
知答案的时期。因此，智慧是通过人们的观察，判断是与非和好与坏的过程。计算机不具备这种功能，也将永远不会拥有这项功能。智慧是人类独有的能力。智慧需要灵魂，它就像人的心脏一样存在于人的大脑中。灵魂绝不是某种机器能够拥有的。
下图表示数据、信息、知识和智慧之间的转换关系。理解是各种转换之间的桥梁。理解融于各阶段之中。
连接
理解
数据表示一种事实或对没有任何关联的事件的描述。
如:下雨了。
信息包含着对一些事件的关系、可能出现的后果的理解。
如:温度下降到15度，然后开始下雨。
知识表现为一种模式，它进一步预测可能发生的事情。
如：由于湿度很高，气温下降，空气支撑不住湿气，所以下雨。
智慧是对更多隐含知识的理解，它以知识为基础。智慧具有系统性。如:因为下雨所以下雨。这其中包含着对所有发生事件的理解:蒸
发、空气流动、温度变化和正在下雨。
然而，何时是知识，何时是噪音仍然需要讨论。
看下面的例子：你可能对上面这个描述表现出绝对的新奇，认为它是噪音。那是因为你不具有与这个描述相关的基础知识，而对于我来说，这个表述相当有意义，因为我理解这个表述，它是牛顿运动第三定律。如果你不理解它，如何能成为你的知识呢？看下面的表述：
●我有一个箱子，长3米，宽3米，高6米；
●箱子很重；
●箱子放在门前；
●当我打开它，发现里面有食物；
●箱子里面比外面冷；
●箱子常放在厨房里；
●箱子的小盒子里有冰；
●当你开门时，光照射进来；
●当移动箱子时，你常会发现下面有很多土；
●箱子顶部存有尘土。
它是什么？
冰箱。你将上面描述的特征与某种形状联系起来，并理解它是对冰箱的描述。所叙述的每一个细节都更加证实了你的理解。
如果你在居住的社会中从未见过冰箱，你可能根本不知道前面的描述说的是什么东西。
当对一个事物的描述与你已有的知识相联系的时候，提供其他任何顺序的描述，你都可以与某个事物联系起来，因为在这之前你已经知道所描述的事物了。
第一章汽车总论 1)Today’s average car contains more than 15,000 separate, individual parts that must work together. These parts can be grouped into four major categories: body, engine, chassis and electrical equipment 。P1 现在的车辆一般都由15000多个分散、独立且相互配合的零部件组成。这些零部件主要分为四类：车身、发动机、底盘和电气设备。 2)The engine acts as the power unit. The internal combustion engine is most common: this obtains its power by burning a liquid fuel inside the engine cylinder. There are two types of engine: gasoline (also called a spark-ignition engine) and diesel (also called a compression-ignition engine). Both engines are called heat engines; the burning fuel generates heat which causes the gas inside the cylinder to increase its pressure and supply power to rotate a shaft connected to the power train. P3 发动机作为动力设备，常见的类型是内燃机，其原理是通过发动机缸内的液体燃料燃烧而产生能量。发动机可分为两类：汽油机（点燃式）和柴油机（压燃式），都属于热力发动机。燃料燃烧产生热量使缸内气压上升，产生的能量驱动轴旋转，并传递给动力传动系。 第二章内燃机 1)Power train system: conveys the drive to the wheels 2)Steering system: controls the direction of movement 3)Suspension system: absorbs the road shocks 4)Braking system: slows down the vehicle P4 传动系把发动机输出的扭矩传递给驱动轮。传动系包括离合器（对应机械变速器）或液力变矩器（对应液力自动变速器）、变速器、驱动轴、主减速器、差速器和驱动桥。 5)Drum brakes have a drum attached to the wheel hub, and braking occurs by means of brake shoes expanding against the inside of the drum. With disc brakes, a disc attached to the wheel hub is clenched between two brake pads. P6 鼓式制动器的制动鼓和轮毂连接，制动蹄张开压紧制动鼓内侧从而产生制动。在盘式制动器上，连着轮毂的制动盘被紧紧夹在两个制动块之间。 1)Linking the piston by a connecting rod to a crankshaft causes the gas to rotate the shaft through half a turn.The power stroke"uses up"the gas,so means must be provided to expel the burnt gas and recharge the cylinder with a fresh petrol-air mixture:this control of gas movement is the duty of the valves;An inlet valve allows the mixture to enter at the right time and an exhaust valve lets out the burnt gas after the gas has done its job . P10 活塞通过连杆和曲轴连接，使得气体带动曲轴旋转半圈。作功冲程耗尽了所有的气体，这样就必须采取相应的措施排出废气并且向气缸内充入新的可燃混合气：气体的运动由气门来控制。进气门使可燃混合气在恰当的时刻进入气缸，排气门使燃烧后的废气排出气缸。 2)The spark-ignition engine is an internal-combustion engine with externally supplied in ignition,which converts the energy cntained in the fuel to kinetic energy.The cycle of operations is spread over four piston strokes. To complete the full cycle it takes two revolutions of the crankshaft. P11 火花点火式发动机是由外部提供点火的内燃机，从而将含在燃料内的能量转化成动能。发动机的一个工作循环分布在活塞的四个行程中，一个完整的工作循环曲轴需要转动两圈。 3)The oil pump in the lubricating system draws oil from the oil pan and sends it to all working parts in the engine. The oil drains off and runs down into the pan. Thus,there is constant circulation of oil between the pan and the working parts of the engine. P15
Unit 1 【Ex1、】根据课文内容,回答以下问题。 1.In human terms and in the broadest sense, information is anything that you are capable of perceiving、 2.It includes written communications, spoken communications, photographs, art, music, and nearly anything that is perceptible、 3.If we consider information in the sense of all stimuli as information, then we can’t really find organization in all cases、 4.No、 5.Traditionally, in libraries, information was contained in books, periodicals, newspapers, and other types of recorded media、People access it through a library’s catalog and with the assistance of indexes, in the case of periodical and newspaper articles、 https://www.doczj.com/doc/cf6296887.html,puterized “information systems”、 7.The problem for most researchers is that they have yet to discover the organizing principles that are designed to help them find the information they need、 8.For library materials, the organizing principle is a detailed subject classification system available for searching in an online “catalog”、 9.The one thing common to all of these access systems is organization、 10.No, it isn’t、 【Ex2、】根据给出的汉语词义与规定的词类写出相应的英语单词。每词的首字母已给出。 n.取回,恢复,修补;检索retrieval n.机械装置,机构,机制mechanism adj.特有的,表示特性的,典型的characteristic n.分类,分级classification n.风格,方式,样式,习惯manner n.文件,公文document vt.解释,说明Interpret vt.使自动化,自动操作automate n.分类assortment n.法则,原则,原理principle n.排列,安排arrangement n.&vt.访问,存取access n.浏览器;浏览书本的人browser n.目录catalog n.索引index n.材料,原料,物资,素材material
Lesson 1 力学的基本概念 1、词汇： statics [st?tiks] 静力学；dynamics动力学；constraint约束；magnetic [m?ɡ＇netik]有磁性的；external [eks＇t?:nl] 外面的, 外部的；meshing啮合；follower从动件；magnitude [＇m?ɡnitju:d] 大小；intensity强度，应力；non-coincident [k?u＇insid?nt]不重合；parallel [＇p?r?lel]平行；intuitive 直观的；substance物质；proportional [pr?＇p?:??n?l]比例的；resist抵抗，对抗；celestial [si＇lestj?l]天空的；product乘积；particle质点；elastic [i＇l?stik]弹性；deformed变形的；strain拉力；uniform全都相同的；velocity[vi＇l?siti]速度；scalar[＇skeil?]标量；vector[＇vekt?]矢量；displacement代替；momentum [m?u＇ment?m]动量； 2、词组 make up of由……组成；if not要不，不然；even through即使，纵然； Lesson 2 力和力的作用效果 1、词汇： machine 机器；mechanism机构；movable活动的；given 规定的，给定的，已知的；perform执行；application 施用；produce引起，导致；stress压力；applied施加的；individual单独的；muscular [＇m?skjul?]]力臂；gravity[ɡr?vti]重力；stretch伸展，拉紧，延伸；tensile[tensail]拉力；tension张力，拉力；squeeze挤；compressive 有压力的，压缩的；torsional扭转的；torque转矩；twist扭，转动；molecule [m likju:l]分子的；slide滑动; 滑行；slip滑，溜；one another 互相；shear剪切；independently独立地，自立地；beam梁；compress压；revolve (使)旋转；exert [iɡ＇z?:t]用力，尽力，运用，发挥，施加；principle原则, 原理，准则，规范；spin使…旋转；screw螺丝钉；thread螺纹； 2、词组 a number of 许多；deal with 涉及，处理；result from由什么引起；prevent from阻止，防止；tends to 朝某个方向；in combination结合；fly apart飞散； 3、译文： 任何机器或机构的研究表明每一种机构都是由许多可动的零件组成。这些零件从规定的运动转变到期望的运动。另一方面，这些机器完成工作。当由施力引起的运动时，机器就开始工作了。所以，力和机器的研究涉及在一个物体上的力和力的作用效果。 力是推力或者拉力。力的作用效果要么是改变物体的形状或者运动，要么阻止其他的力发生改变。每一种
About car engine Of all automobile components,an automobile engie is the most complicated assembly with dominant effects on the function of an autombile.So, the engine is generally called the"heat"of an automobile. 在汽车的所有部件中，汽车发动机是最复杂的组件，其对整车性能有着决定性的作用。因而发动机往往被称作发动机的“心脏”。 There are actually various types of engines such as electric motors,stream engines,andinternal combustion engines.The internal combustion engines seem to have almost complete dominance of the automotive field.The internal combustion engine,as its name indicates,burns fuel within the cylinders and converts the expanding force of the combustion into rotary force used to propel the vehicle. 事实上，按动力来源分发动机有很多种，如电动机、蒸汽机、外燃机等。然而内燃机似乎在发动机领域有着绝对的统治地位。就像其字面意思一样，内燃机的染料在气缸内燃烧，通过将燃烧产生气体的膨胀力转换成转动力来驱动发动机前进。 Engine is the power source of the automobile.Power is produced by the linear motion of a piston in a cylinder.However,this linear motion must be changed into rotary motion to turn the wheels of cars or trucks.The puston attached to the top of a connecting rod by a pin,called a piston pin or wrist pin.The bottom of the connecting rod is attached to the crankshaft.The connecting rod transmits the up-and-down motion of the piston to the crankshaft,which changes it into rotary motion.The connecting rod is mounted on the crankshaft with large bearings called rod bearing.Similar bearings, called main bearings,are used to mount the crankshaft in the block. 发动机是整部车的动力来源。能量来自于活塞在气缸内的（往复）直线运动。然而这种（往复）直线运动必须要转换成旋转运动才能驱动车轮。活塞与连杆通过一个销来连接，这个销称为活塞销。连杆的下部连接于曲拐。连杆把活塞的上下往复运动传递给曲拐，从而将往复直线运动转变成旋转运动。连杆和曲拐的连接使用大的轴承，称之为连杆轴承，类似的轴承也用于将曲轴连接到机体，称之为主轴承。 They are generally two different types of cooling system:water-cooling system and air-cooling system.Water-cooling system is more common.The cooling medium, or coolant, in them is either water or some low-freezing liquid, called antifreeze.A water-cooling system consists of the engine water jacket, thermostat, water pump, radiator, radiator cap, fan, fan drive belt and neccessary hoses. 主要有两种类型的冷却系统：水冷和风冷。水冷系统更为普遍。系统所用冷却介质或是冷却液常委水或其他低凝固点液体，称为抗凝剂。一个完整的水冷系统包括机体水套，节温器，水泵，散热器，散热器罩，风扇，风扇驱动皮带和必需的水管。 A water-cooling system means that water is used as a cooling agent to circulate through the engine to absorb the heat and carry it to the radiator for disposal.The ebgine is cooled mainly through heat transfer and heat dissipation.The heat generated by the mixture burned in the engine must be transferred from the iron or aluminum cylinder to the waterin the water jacket.The outside of the water jacket dissipates some of the heat to the air surrounding it, but most of the heat is carried by the cooling water to the radiator for dissipation.When the coolant temperature in the system reaches 90°,the termostat valve open fully, its slanted edge shutting off
专业英语 一、专业术语 RFID射频识别IOT物联网Cloud Computing云计算ANN神经网络BI商业智能E-business /Web-business / e-commerce电子商务KM知识管理GIS地理信息系统PDA掌上电脑Bluetooth蓝牙技术CAD计算机辅助设计CMD计算机辅助制作branch manager部门经理binary format二进制格式USB（Universal Serial Bus）通用串行总线computer case计算机机箱 temporary storage of information临时存储信息floppy disk软盘CD-ROM只读光盘textual源代码video card视频卡，显卡sound card音频卡，声卡 DVD数字化视频光盘SISP战略信息系统计划Project Management项目管理Human Resources人力资源End-User Systems Development最终用户系统开发rolling business plans流动业务计划MIS(management information system)管理信息系统DB（database）数据库DBMS（database Management system）数据库管理系统DSS（decision support system）决策支持系统operational manager运营经理Senior manager 高级经理semi-structured decision半结构化决策 ANS（Advanced Network&Service）高级网络及服务公司 TPS（Transaction Processing systems）事务管理系统 KWS（Knowledge Work Systems）只是工作系统GRASP绘制机器人技术应用软件包OAS（Office Automation Systems）办公自动化系统 ESS（Executive Support Systems）经理支持系统 EIS（Executive Information Systems）经理信息系统 OLAP（on-line analytical processing）联机分析处理 GIS（Group Information Systems）集群信息系统 GDSS（Group Decision Support Systems）集群决策支持系统 MIT（Management Information technology）管理信息技术 RAD（rapid application development）快速应用开发 Two-way communications 双工通讯client-server environment 客户服务环境Data warehouse 数据仓库logistics information systems 物流信息系统 ERP（Enterprise resource planning）企业资源规划 CRM（customer relationship Management）客户关系管理 OOD（Object-Oriented design）面向对象设计 OOP（Object0Oriented Programming）面向对象编程 HLLs（High Level Languages）高级语言ADTs（Abstract Data Types）抽象数据类型Software Ics软件的组成单元machine code机器码op-code输出码 EDI（Electronic Data interchange）电子数据交换 SMEs（small and medium sized enterprises）中小企业 B2B企业对企业电子商务B2C企业对用户电子商务 CERT(Character Error Rate Tester)字符出错率测试器 CIAS（Communication Link Analyzer System）通信链路分析系统 IMS（Information Management System）管理信息系统 NDMS（Netware Data Management System）网络数据管理系统
2、应力和应变 在任何工程结构中独立的部件或构件将承受来自于部件的使用状况或工作的外部环境的外力作用。如果组件就处于平衡状态,由此而来的各种外力将会为零,但尽管如此,它们共同作用部件的载荷易于使部件变形同时在材料里面产生相应的内力。 有很多不同负载可以应用于构件的方式。负荷根据相应时间的不同可分为: (a)静态负荷是一种在相对较短的时间内逐步达到平衡的应用载荷。 (b)持续负载是一种在很长一段时间为一个常数的载荷, 例如结构的重量。这种类型的载荷以相同的方式作为一个静态负荷; 然而,对一些材料与温度和压力的条件下,短时间的载荷和长时间的载荷抵抗失效的能力可能是不同的。 (c)冲击载荷是一种快速载荷(一种能量载荷)。振动通常导致一个冲击载荷, 一般平衡是不能建立的直到通过自然的阻尼力的作用使振动停止的时候。 (d)重复载荷是一种被应用和去除千万次的载荷。 (e)疲劳载荷或交变载荷是一种大小和设计随时间不断变化的载荷。 上面已经提到，作用于物体的外力与在材料里面产生的相应内力平衡。因此,如果一个杆受到一个均匀的拉伸和压缩，也就是说, 一个力,均匀分布于一截面,那么产生的内力也均匀分布并且可以说杆是受到一个均匀的正常应力,应力被定义为 应力==负载 P /压力 A, 因此根据载荷的性质应力是可以压缩或拉伸的,并被度量为牛顿每平方米或它的倍数。 如果一个杆受到轴向载荷，即是应力，那么杆的长度会改变。如果杆的初始长度L和改变量△L已知，产生的应力定义如下: 应力==改变长△L /初始长 L 因此应力是一个测量材料变形和无量纲的物理量 ,即它没有单位;它只是两个相同单位的物理量的比值。 一般来说,在实践中,在荷载作用下材料的延伸是非常小的, 测量的应力以*10-6的形式是方便的, 即微应变, 使用的符号也相应成为ue。 从某种意义上说，拉伸应力与应变被认为是正的。压缩应力与应变被认为是负的。因此负应力使长度减小。 当负载移除时，如果材料回复到初始的，无负载时的尺寸时，我们就说它是具有弹性的。一特定形式的适用于大范围的工程材料至少工程材料受载荷的大部分的弹性, 产生正比于负载的变形。由于载荷正比于载荷所产生的压力并且变形正比于应变, 这也说明,当材料是弹性的时候, 应力与应变成正比。因此胡克定律陈述, 应力正比于应变。 这定律服从于大部分铁合金在特定的范围内, 甚至以其合理的准确性可以假定适用于其他工程材料比如混凝土，木材，非铁合金。 当一个材料是弹性的时候，当载荷消除之后，任何负载所产生的变形可以完全恢复,没有永久的变形。
unit1 body 车身chassis 底盘enclosure外壳、套hood车棚、车顶sway 摇摆frame车架steering转向、操作brake 制动weld焊接rivet铆钉bolt螺钉washer垫圈vibration 振动stabilizer稳定器ride乘坐舒适性handling操作稳定性linkages转向传动机构plier钳子distributor分电器alternator交流发电机regulator调节器carburetor化油器radiator散热器、水箱defroster除冰装置sludge金属碎屑transmission变速器differential 差速器power train 传动系unitized body 承载式车身suspension system 悬架系统steering system 转向系braking system 制动系shock absorbers减震器control arms控制臂steering wheel 转向盘steering column转向管柱steering gears 转向器tie rod 横拉杆idler arm随动臂brake shoe制动蹄disc brake 盘式制动器drum brakes 鼓式制动器ignition system 点火系统exhaust system 排气系统lubrication system 润滑系oil filters 机油滤清器drive（or propeller）shaft传动轴universal joints 万向节dynamo发电机horn喇叭swived 旋转steering box转向器timing gear 正时齿轮bevel gear 锥齿轮mesh with与啮合leaf spring 钢板弹簧stub axle 转向节 unit2 longitudinal纵向的transverse横向的reciprocate往复spin旋转piston活塞ignite点火rub摩擦quart夸脱reservoir油箱mechanical机械的enclosed被附上的gallon加仑stroke冲程camshaft凸轮轴combustion燃烧disengaged脱离啮合的flywheel飞轮internal-combustion engine内燃机diesel-fuel柴油LPG=Liquefied Petroleum Gas液化石油气体CNG=Compressed natural gas压缩天然气spark ignition火花点火compression ignition压缩点火spark plug火花塞gas-turbine engine蒸汽机Stirling engine斯特灵发动机lubricating system润滑系统oil pan油底壳oil pump机油泵exhaust system排气系统emission-control system排放控制系统energy conversion能量转换air/fuel ratio空燃比connecting rod连杆TDC=Top Dead Center上止点BDC=Bottom Dead Center 下止点intake stroke进气冲程compression stroke压缩冲程power stroke作功冲程exhaust stroke排气冲程compression ratio压缩比lifter挺柱rocker摇臂retainer弹簧座seal密封件tappet 推杆lobe凸起gasket垫圈valve train配气机构cam follower气门挺柱rocker arm摇臂combustion chamber燃烧室intake valve进气阀exhaust valve排气阀valve stem气门杆valve cover气门室盖valve port阀口valve guide气门导管 unit3
机械制造专业英语文章 篇一：机械专业英语文章中英文对照 Types of Materials 材料的类型 Materials may be grouped in several ways. Scientists often classify materials by their state: solid, liquid, or gas. They also separate them into organic (once living) and inorganic (never living) materials. 材料可以按多种方法分类。科学家常根据状态将材料分为：固体、液体或气体。他们也把材料分为有机材料(曾经有生命的)和无机材料(从未有生命的)。 For industrial purposes, materials are divided into engineering materials or nonengineering materials. Engineering materials are those used in manufacture and become parts of products. 就工业效用而言，材料被分为工程材料和非工程材料。那些用于加工制造并成为产品组成部分的就是工程材料。 Nonengineering materials are the chemicals, fuels, lubricants, and other materials used in the manufacturing process, which do not become part of the product. 非工程材料则是化学品、燃料、润滑剂以及其它用于加工制造过程但不成为产品组成部分的材料。 Engineering materials may be further subdivided into: ①Metal ②Ceramics ③Composite ④Polymers, etc. 工程材料还能进一步细分为：①金属材料②陶瓷材料③复合材料④聚合材料，等等。 Metals and Metal Alloys 金属和金属合金 Metals are elements that generally have good electrical and thermal conductivity. Many metals have high strength, high stiffness, and have good ductility. 金属就是通常具有良好导电性和导热性的元素。许多金属具有高强度、高硬度以及良好的延展性。 Some metals, such as iron, cobalt and nickel, are magnetic. At low temperatures, some metals and intermetallic compounds become superconductors. 某些金属能被磁化，例如铁、钴和镍。在极低的温度下，某些金属和金属化合物能转变成超导体。 What is the difference between an alloy and a pure metal? Pure metals are elements which come from a particular area of the periodic table. Examples of pure metals include copper in electrical wires and aluminum in cooking foil and beverage cans. 合金与纯金属的区别是什么？纯金属是在元素周期表中占据特定位置的元素。 例如电线中的铜和制造烹饪箔及饮料罐的铝。 Alloys contain more than one metallic element. Their properties can be changed by changing the elements present in the alloy. Examples of metal alloys include stainless steel which is an alloy of iron, nickel, and chromium; and gold jewelry which usually contains an alloy of gold
Fuel Supply System of Gasoline Engine(UNIT SEVEN) All the gasoline engines have substantially identical fuel systems and run on a mixture consisting of fuel vapor and air. The fuel system comprises the units designed to store, clear and deliver fuel, the units intended to clean air and a unit for preparing a mixture from fuel vapor and air. In a fuel system different components are used to supply fuel from the fuel tank into the engine cylinder. Some of the important components are fuel tank, fuel pump, fuel filter, carburetor, intake manifold and fuellines or tubes connecting the tank, pump and the carburetor. The fuel tank is a fuel container used for storing fuel. It is made of sheet metal. It is attached to the vehicle frame with metal traps and is located at the rear of the vehicle. They are mounted in a boot or boot-floor pan in case of front-engined cars and small commercial vehicles. In order to strengthen the tank as well as to prevent surging of fuel when the vehicle rounds a curve of suddenly stops, baffle plates are attached to the inside of the tank. A cap is used to close the filler opening of the tank. The fuel line is attached at or near the bottom of the tank with a filtering element placed at the connection. The other components of the fuel tank are the fuel gauge sending unit, a vent pipe, receiving unit. To prevent the dirt and water from entering the luggage compartment, a sealing strip is fitted between the fuel tank and boot floor pan. Moreover to limit the transmission of frame distortion to the tank giving rise to squeaking as the metal parts get rubbed together, rubber or felt pads are often fitted between the mountings and the tank. Provision is also made against drumming of the tank by these mountings. The tank may be placed at the side of the chassis frame for convenience in case of large commercial vehicles. The length of the connecting lines or tubes from the tank to the carburetor is also restricted by this at the same time. A porous filter is attached to the outlet lines. By drawing fuel from the tank through the filter, any water in the bottom of the tank as well as any dirt into the fuel gathers on the surface of the filter. To keep the fuel always under atmospheric pressure, the filter pipe or tank is vented. In order to prevent dirt in the fuel from entering the fuel pump or carburetor, fuel filters and screens are used in the fuel system. If the dirt is not removed from the fuel, the normal operation of these units will be prevented. The engine performance will also be reduced.
INTERNAL COMBUSTION ENGINE 引擎燃烧室 1. principle of operation 原理 Engine and power : Engine is used to produce power. The chemical energy in fuel is converted to heat by the burning of the fuel at a controlled rate. This process is called combustion. If engine combustion occurs with the power chamber. ,the engine is called internal combustion engine. If combustion takes place outside the cylinder, the engine is called an external combustion engine. Engine used in automobiles are internal combustion heat engines. Heat energy released in the combustion chamber raises the temperature of the combustion gases with the chamber. The increase in gas temperature causes the pressure of the gases to increase. The pressure developed within the combustion chamber is applied to the head of a piston to produce a usable mechanical force, which is then converted into useful mechanical power. 译: 引擎和能量: 引擎为汽车提供能量，燃料的化学能通过燃烧，转化为热能，这个过程叫燃烧。假如燃烧在燃烧室，这样的发动机叫内燃机。假如燃烧在气缸外，这样的发动机叫外燃机。 用在汽车上的一般是内燃机，热能在燃烧室释放，燃烧室气体温度升高。气体温度的升高使气体的压力曾加，燃烧室内的高压气体作用在活塞头部产生可以利用的化学能，化学能转化为机械能。 Engine T erms : Linking the piston by a connecting rod to a crankshaft causes the gas to rotate the shaft through half a turn. The power stroke “uses up” the gas , so means must be provided to expel the burnt gas and recharge the cylinder with a fresh petrol-air mixture :this control of gas movement is the duty of the valves ;an inlet valve allows the new mixture to enter at the right time and an exhaust valve lets out the burnt gas after the gas has done its job. Engine terms are : TDC(Top Dead Center):the position of the crank and piston when the piston is farther away from the crankshaft. BDC(Bottom Dead Center):the position of the crank and piston when the piston is nearest to the crankshaft. Stroke : the distance between BDC and TDC; stroke is controlled by the crankshaft. Bore : the internal diameter of the cylinder. Swept volume : the volume between TDC and BDC Engine capacity : this is the swept volume of all the cylinder e.g. a four-stroke having a capacity of two liters(2000cm) has a cylinder swept volume of 50cm. Clearance volume: the volume of the space above the piston when it is at TDC. Compression ratio = (swept vol + clearance vol)\(clearance vol) Two-stroke : a power stroke every revolution of the crank.