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1、毕业设计(论文)外文资料翻译系部： 机械工程系 专 业： 机械工程及自动化 姓 名： 学 号： 外文出处：http:/ 附 件： 1.外文资料翻译译文；2.外文原文。 指导教师评语： 此翻译文章简单介绍了内燃机的原理，详细描述了内燃机各零部件在内燃机工作时所起到的作用，翻译用词比较准确，文笔也较为通顺，为在以后工作中接触英文资料打下了基础。 签名： 年 月 日注：请将该封面与附件装订成册。附件1：外文资料翻译译文内燃机我们知道，无论是汽油发动机还是柴油发动机，它们都属于内燃机，都是燃烧燃料后通过推动气缸内活塞作往返运动来将燃料中的化学能量转换成为驱动车辆前进的机械能量，因此两者的工作原理大体是
2、相同的。作为日常使用的燃料本身，柴油的能量密度最高，比液化天然气高出近1倍，比汽油高出10%以上。与汽油相比，柴油不易挥发，着火点较高，不易因偶然情况被点燃或发生爆炸。由于两者挥发性和燃点的不同，导致使用这两种燃料的发动机有不同的点火方式。汽油发动机的特点：体积小、重量轻、起动性好。汽油发动机中，油气混合气进入气缸后，在压缩接近终了时由火花塞点燃。因此，汽油发动机需要一套控制何时让火花塞工作的点火系统，此系统必须精确控制火花塞放电的时刻和火花能量的大小，才能保证汽油机的工作正常，汽油机的燃料供给系和点火系是汽油机上发生故障比例较高的部位。此外，由于汽油的燃点较低，汽油机的压缩比就不能太高，以免
3、油气自燃，因此其热效率和经济性较柴油机为差。汽油机的优点在于其体积小、重量轻、价格便宜；起动性好，最大功率时的转速高；工作中振动及噪声小，因此，在载客汽车，特别是轿车中，汽油机得到了广泛的应用，特别是在我们国家目前生产的绝大多数轿车，都是采用汽油发动机作为自己的动力系统。传统柴油发动机的特点：热效率和经济性较好。柴油机采用压缩空气的办法提高空气温度，使空气温度超过柴油的自燃燃点，这时再喷入柴油、柴油喷雾和空气混合的同时自己点火燃烧。因此，柴油发动机无需点火系。同时，柴油机的供油系统也相对简单，因此柴油发动机的可靠性要比汽油发动机的好。由于不受爆燃的限制以及柴油自燃的需要，柴油机压缩比很高。热效
4、率和经济性都要好于汽油机，同时在相同功率的情况下，柴油机的扭矩大，最大功率时的转速低，适合于载货汽车的使用。但柴油机由于工作压力大，要求各有关零件具有较高的结构强度和刚度，所以柴油机比较笨重，体积较大；柴油机的喷油泵与喷嘴制造精度要求高，所以成本较高；另外，柴油机工作粗暴，振动噪声大；柴油不易蒸发，冬季冷车时起动困难。由于上述特点，以前柴油发动机一般用于大、中型载重货车上。小型高速柴油发动机的新发展：排放已经达到欧洲III号的标准。传统上，柴油发动机由于比较笨重，升功率指标不如汽油机(转速较低)，噪声、振动较高，炭烟与颗粒(PM)排放比较严重，所以一直以来很少受到轿车的青睐。但随着近年来柴油机
5、技术的进步，特别是小型高速柴油发动机的新发展，一批先进的技术，例如电控直喷、共轨、涡轮增压、中冷等技术得以在小型柴油发动机上应用，使原来柴油发动机存在的缺点得到了较好的解决，而柴油机在节能与CO2排放方面的优势，则是包括汽油机在内的所有热力发动机无法取代的，因此，先进的小型高速柴油发动机，其排放已经达到欧洲III号的标准，成为“绿色发动机”，目前已经成为欧美许多新轿车的动力装置，可以预见，我国将出现越来越多的柴油轿车。内燃机是一种热力发动机。通常可按燃用的燃料来分有：汽油机、煤气机等几类。因为汽油机轻便、噪音低以及环保性，它赢得了公众较好的口碑，因此其有机在国民经济和国防工程上得到了较为广泛的
6、应用。内燃机传热在很大程度上主宰着汽油机的经济性、可靠性以及其他各项重要的技术经济指标。在汽油机负载日益增强的今天，研究汽油机热负荷问题已经是非常紧迫的任务了。汽油机向高强化方向的发展使其零部件的机械负荷和热负荷不断增大，而汽油机的的汽缸套是气体压缩、燃烧和膨胀的空间，并为活塞起导向作用，它的不正常变形将破坏活塞与缸套间的正常间隙，导致工作过程的恶化。因而，如何降低汽油机的热负荷，则是提高其整机性能的重要研究课题。 发动机：发动机充当动力装置。内燃机是最常见的：它通过在发动机汽缸里面燃烧一种液体燃料获得动力。发动机有两种类型:汽油机 (也叫做一个火花- 点火发动机)和柴油机(也被称为一个压缩-
7、 点火发动机)。这两种发动机都叫做热机；燃料在气缸内燃烧产生的高温高压气体推动曲轴旋转而传递动力。车身：汽车车身是由窗子，门，一个发动机罩和一个行李舱盖建成的一个金属板壳。它给发动机，乘客和货物提供一种保护。车身的设计应使得乘客安全和舒适。车身的外表使得汽车具有吸引人的，五彩缤纷的和现代的外表。底盘：底盘是汽车上主要操作系统组成的一个总成。底盘包括传动系，悬挂，转向，以及刹车系统。传动系统 - 把动力运送到车轮。主要零部件是离合器，变速器，传动轴，主减速器，和差速器。悬挂 - 吸收路面震动。转向 - 控制运动的方向。刹车 使车辆减速。电气设备：电系统为点火，喇叭，灯光，发热器和起动器提供电。通
8、过循环充电来维持电量。这条电路由电池，交流发电机(或者发电机)组成。蓄电池储存电。交流发电机把发动机的机械能换成电能并给电池再充电。气缸体：气缸体是发动机的基本框架。发动机的其他零件都安装在它里面或者固定在它上。缸体里有气缸，水套和油道。曲轴也固定在气缸体底部。除了顶置凸轮(OHC)发动机以外，凸轮轴都安装在气缸体里面。在大多数汽车里，气缸体由灰铸铁或者一种灰铸铁和其他金属的合金(混合物)做成，例如镍或铬。气缸体是铸件。 有些气缸体，特别是在小汽车里的那些，都是由铝做成的。这种金属比铸铁轻得多。但是，铸铁的耐磨性比铝好。因此，在大多数铝制发动机的气缸内镶有铸铁或者钢的轴套。这些轴套叫做气缸套。
9、而有些气缸体完全由铝做成。气缸盖：气缸盖固定在气缸体的顶上，正像屋顶套在一所房子上面一样。气缸盖下面与活塞顶上的空间形成燃烧室。最常见的气缸盖类型是半球形，楔形和准半球形。这三种说法都是指燃烧室的形状。气缸盖携带阀门，气门弹簧和在摇臂杆上的摇臂，这部分的气门传动机构通过推杆工作。有时，凸轮轴直接安装在气缸盖上并且不用摇臂控制阀门工作。这被叫为顶置凸轮轴装置。像气缸体一样，气缸盖是由铸铁或者铝合金制成。衬垫：气缸盖与气缸体用高强度的钢螺栓缚连结。气缸体和气缸盖之间的连接必须密封以便没有燃烧的混合气体泄漏。这通过使用气缸盖衬垫实现。这是一个夹层衬垫，即在两片铜之间放一片石棉，这两种材料都能禁得住在
10、发动机内的高温和高压。油底壳：油底壳通常由钢冲压形成。油底壳和气缸体的下半部分一同被叫做曲轴箱；他们把曲轴封闭起来。润滑系统中的机油泵从油底壳抽取油并把油输送到发动机内全部正在工作的部分。机油流出后又流回油底壳。因而在油底壳和发动机工作零件之间有机油不断流动循环。进气配气定时：如果进口门在进气行程的上止点打开并且在这次行程的下止点关闭，它将有180的开度。气门在180转角内完全打开。然而气门达到全开位置需要一定时间，完全关闭也需要一定时间。因此阀门在上止点(BTDC)之前被打开，在下止点(ABDC)之后关闭。排气配气定时： 如果排气门在排气行程的下止点打开并且在这次行程的上止点关闭，它将有18
11、0的持续。但是像进气门一样，排气门需要时间到达充分打开和关闭的位置。因此排气门在下止点之前打开，在上止点之后关闭。 气门重叠：进气门在上止点前17打开，排气门在上止点后17关闭。 因此，有34的一段时期，两个阀门都是开的：(17+ 17= 34)。这时期被称为气门重叠。排气门的关闭和进气门的开启重叠。在这个时候，新的混合气推动燃烧后的废气从排气门排出。在涡轮增压发动机上气门重叠角被保持在一个最小值。这就防止废气倒流入进气管。 配气机构：那些打开和关闭气门的气门传动是为了协调四冲程的工作循环(使他们各自上下移动)。这些阀门运动必须正好在合适的时刻进行。每个阀门的开启由凸轮轴控制。顶置凸轮轴气阀传
12、动：凸轮是一在轴上的蛋形的金属，通过曲轴协调旋转。那金属轴叫凸轮轴，在发动机里的每个气门一般有各自的凸轮。当凸轮轴旋转时，凸轮凸起的或者高点的位置，推动气门座。这行动强迫阀门向下移动。这过程能使进气门在进气行程打开，或者排气门在排气行程打开。 因为凸轮轴继续旋转，凸轮轴上的凸起部分离开气门装置。当这发生时，气门弹簧紧紧地关闭气门口，叫做气门座。现代汽车发动机里的阀门位于发动机顶上的汽缸盖。这被称为顶置气门(OHV)结构。另外，当凸轮轴位于汽缸盖上面时，这种方式被称为是顶置凸轮轴(OHC)结构。一些高性能发动机有两个单独的凸轮轴，分别负责开关进气门和排气门。这些发动机被称为双顶置凸轮轴(DOHC
13、)发动机。推杆气阀传动：凸轮轴也装在发动机底部的气缸体内。为了将凸轮的运动传给气门需要一些附属装置。在这种布置中，凸轮凸角推动凸轮挺杆。当凸轮的凸角在凸轮挺杆下出现时，它推动凸轮挺杆向上运动(离开凸轮轴)。凸轮挺杆推动控制摇臂的推杆。摇臂以通过它的中心为轴而旋转。当摇臂的一侧上升，其另一侧下降，正如一块跷跷板一样。摇臂向下移动的那一边推动气门杆以打开气门。 因为推杆气阀传动有另外的部分，所以很难以高速运转。推杆发动机一般在低速运转，从而产生比相同大小的顶置凸轮轴较少功率。(记住，功率反映了工作能力。) 气门间隙：当发动机处于压缩行程和做功行程时，阀门必须紧紧地关闭以产生一个不透气的气封，以防止
14、气体逃离燃烧室。如果阀门不完全关闭，发动机将不能发挥全部动力。此外气门头易于被通过的热气体燃烧，这有可能使活塞频繁冲击打开的气门，使发动机严重损坏。 所以阀门能完全关闭，气门间隙在操作机构内是必须的。这意味着操作机构必须离阀门足够远以允许阀门通过气门弹簧使其完全关闭。但是，如果间隙太大，将引起金属轻敲的噪音。凸轮轴驱动机构：在四行程循环时，每凸轮必须旋转打开一阀门。记住，一个循环相当于曲轴旋转两次。因此，凸轮轴必须以曲轴正好一半的速度旋转。这用2：1的传动比完成。齿轮连接到凸轮轴的齿数是齿轮连接到曲轴的两倍。齿轮连结有三种方式：（1）皮带传动齿型带能被使用。这样的带是由合成橡胶做成并且用内部的
15、钢或者玻璃纤维绞合加强。皮带上有齿，或者槽以啮合并且驱动传动齿轮上的齿。皮带一般与顶置凸轮阀门传动一起被用在发动机上。（2）链传动在一些发动机上，金属链被用来连结曲轴和凸轮轴齿轮。大多数推杆发动机和一些顶置凸轮轴发动机都有链。（3）齿轮传动凸轮轴和曲轴齿轮可能被直接连结，或者相啮合。这类操作联动通常被用在更老的六气缸，直列发动机上。凸轮轴被链或者带驱动，使其朝着曲轴相同的方向转动。但是凸轮轴被曲轴齿轮直接驱动，其将在相反方向上转动。正时皮带被使用，因为他们花费少于链子，而且噪音少。一条典型的正时皮带由用玻璃纤维加强的氯丁橡胶(合成橡胶)做成的。附件2：外文原文belong engineWe k
16、now that both gasoline engines or diesel engines, they all belong engine. all from the burning of fuel through the cylinder piston made from the campaign to promote the fuel conversion of chemical energy into mechanical energy driving the vehicle forward. So the working principle is generally the sa
17、me.Daily use as fuel itself, the highest energy density of diesel, liquefied natural gas nearly doubled over, more than 10% higher than gasoline. Compared with conventional gasoline, diesel not volatile, higher ignition point, the situation was not due to accidental fire or explosion. Because of the
18、 volatile and, if different, resulting in the use of two different fuels the engine ignition.Gasoline Engine features : small size, light weight, good start.Gasoline engines, the gas mixture into the cylinder, close to the end of the compression ignited by the spark plug. Therefore, the need for a g
19、asoline engine when to control the spark plug ignition system. This system requires an accurate control of spark plugs and spark discharge energy of the moment, be able to ensure the normal gasoline engine. gasoline engine fuel supply system and ignition system is a high proportion of the gasoline e
20、ngine fault location. In addition, the gasoline ignited lower gasoline engine compression ratio can not be too high so as to avoid spontaneous combustion of oil and gas. Therefore the thermal efficiency and economy worse than diesel.The advantage lies in its small gasoline engine, light weight, low
21、price; Start good, the speed at maximum power; Small vibration and noise work, therefore, passenger motor vehicles, particularly cars, has been widely used in gasoline engines. especially in the vast majority of our countrys current production cars, as their gasoline engines are used on the power sy
22、stem.The conventional diesel engine thermal efficiency and economy better characteristics :Diesel use of compressed air and improve air temperature, air temperature over the spontaneous ignition of diesel. Then again injected into diesel, hybrid diesel spray at the same time their ignition and combu
23、stion air. Therefore, no diesel engine ignition system. Meanwhile, the engine oil system is relatively simple and therefore the reliability of diesel engines than gasoline engines as good.From injuries caused by spontaneous combustion due to the restrictions and the need for diesel engine with a hig
24、h compression ratio. Thermal efficiency and economy must be better than the gasoline engine, while the power in the same circumstances, the engine torque, maximum power at low speed, suitable for use in the truck.However, due to work pressure Diesel called on the structural components with high stre
25、ngth and stiffness. So Diesel relatively bulky size; Diesel fuel pump with the nozzle to create high-precision, high costs; In addition, the engine crude, large vibration and noise; Diesel easy evaporation in winter when cold starting problems.Because of these features, previously used in diesel eng
26、ines, medium radial truck.The new development : small high-speed diesel engine emission standards has been achieved in Euc22 rope III.Traditionally, due to relatively heavy diesel engine or gasoline engine power as indicators (low speed), noise, vibration higher. Smoke and carbon particles (PM) emis
27、sions is fairly serious, very little has been favored by car.But with the advances in technology in recent years Diesel, especially small high-speed diesel engine is a new development of a number of advanced technologies, For example, electronic control DI, common rail, turbo-charged, in the cold li
28、ght of technology, such as the use of diesel engines. The shortcomings of the original diesel engine to be a better solution. and the diesel engines advantages in energy and CO2 emissions. including the gasoline engine is no way to replace all heat engines, advanced high-speed small diesel engines.
29、The European III emission standards has been achieved, the green engine that Many cars in Europe and the United States has now become the new power plant, it can be predicted that China will see an increasing number of diesel cars.ICE is a heat engine. Usually can burn the fuel used to be in : gasol
30、ine engine, gas and other types of aircraft. Because the gasoline engine light, low noise and environmental protection, it won the public good reputation, Therefore organic in its national economy and national defense projects has been more widely used. Engine Heat Transfer to a large extent the key
31、 to the economic gasoline engine, reliability and other important technical and economic indicators. The gasoline engine load increasing today, the research gasoline engine heat load problems is very urgent task. High gasoline engine to enhance the development direction of its mechanical parts load
32、and thermal load is increasing, and The gasoline engine and the cylinder sets of gas compression, combustion and expansion of the space, and to orient the Pistons, Its not normal deformation of the cylinder and piston damage the normal clearance, resulting in the deterioration process. Therefore, ho
33、w to reduce the gasoline engine heat load, it is to enhance its overall performance an important research topic. EngineThe 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
34、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 tran
35、smission.BodyAn automobile body is a sheet metal shell with windows, doors, a hood, and a trunk deck built into it. It provides a protective covering for the engine, passengers, and cargo. The body is designed to keep passengers safe and comfortable. The body styling provides an attractive, colorful
36、, modern appearance for the vehicle.ChassisThe chassis is an assembly of those systems that are the major operating part of a vehicle. The chassis includes the transmission, suspension, steering, and brake systems.Transmission systems conveys the drive to the wheels. The main components are clutch,
37、gearbox, driveshaft, final drive, and differential.Suspension absorbs the road shocks.Steering controls the direction of the movement.Brake slows down the vehicle.Electrical EquipmentThe electrical system supplies electricity for the ignition, horn, lights, heater, and starter. The electricity level
38、 is maintained by a charging circuit. This circuit consists of the battery, alternator (or generator). The battery stores electricity. The alternator changes the engines mechanical energy into electrical energy and recharges the battery.Engine BlockThe engine block is the basic frame of the engine.
39、All other engine parts either fit inside it or fasten to it. It holds the cylinders, water jackets, and oil galleries.The engine block also holds the crankshaft, which fastens to the bottom of the block. The camshaft also fits inside the block, except on overhead-cam engines (OHC). In most cars, thi
40、s block is made of gray iron, or an alloy (mixture) of gray iron and other metals, such as nickel or chromium. Engine blocks are castings. Some engine blocks, especially those in smaller cars, are made of cast aluminum. This metal is much lighter than iron. However, iron wears better than aluminum.
41、Therefore, the cylinders in most aluminum engines are lined with iron or steel sleeves. These sleeves are called cylinder sleeves. Some engine blocks are made entirely of aluminum.Cylinder HeadThe cylinder head fastens to the top of the block, just as a roof fits over a house. The underside forms th
42、e combustion chamber with the top of the piston. The most common cylinder head types are the hemi, wedge, and semi-hemi.All three of these terms refer to the shape of the engines combustion chamber. The cylinder head carries the valves, valve springs and the rockers on the rocker shaft, this part of
43、 the valve gear being worked by the push-rods. Sometimes the camshaft is fitted directly into the cylinder head and operates on the valves without rockers. This is called an overhead camshaft arrangement. Like the cylinder block, the head is made from either cast iron or aluminum alloy.GasketThe cyl
44、inder head is attached to the block with high-tensile steel studs. The joint between the block and the head must be gas-tight so that none of the burning mixture can escape. This is achieved by using cylinder head gasket. This is a sandwich gasket, i.e. a sheet of asbestos between two sheets of copp
45、er, both these materials being able to withstand the high temperature and pressures within the engine.Oil Pan or SumpThe oil pan is usually formed of pressed steel. The oil pan and the lower part of the cylinder block together are called the crankcase; they enclose, or encase, the crankshaft. The oi
46、l 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.Inlet Valve TimingIf the inlet valve opened at TD
47、C of the intake stroke and closed at BDC of that stroke, it would have a duration of 180.It would have remained open for half of a complete 360 revolution, or 180. However, it takes some time for the valve to open to its full position. It also takes time for it to close tightly. Therefore the valve
48、is opened before TDC (BTDC) and closed after BDC (ABDC).Exhaust Valve TimingIf the exhaust valve opened at BDC at the beginning of the exhaust stroke and closed at TDC at the end of the exhaust stroke, it would have a duration of 180. But like the inlet valve, the exhaust valve needs time to reach the full-open position, It also ne