Lesson-4-Diesel-Engine-Construction(2).doc

Lesson 4 Diesel Engine Construction (2)第4课 柴油机结构 (2)Pistons and piston rods活塞及活塞杆A piston consists of a lower part-piston skirt of cast iron-and a upper part or crown made of a special heat-resistant steel.活塞由其下部铸铁制成的活塞裙, 以及上部耐热钢制成的活塞头组成。They are bolted together and fixed to the piston rod.它们用螺栓连在一起并固定在活塞杆上。The position of the piston parts in relation to each other is secured by means of machine-turned recesses and a dowel pin in the crown.活塞部件相互间的位置由活塞头上车削的凹槽和定位销来固定。Each piston is provided with five or six piston rings fitted in chromium plated grooves in the crown.每个活塞装有五至六道活塞环, 活塞环装在头部镀铬的环槽中。The two or three topmost rings are narrow rings having diagonal cuts, while the next two are broad and are provided with overlapping end joints.最上面的两三道活塞环是带斜切口的窄环, 紧接下去的两道活塞环是带有重叠搭口的宽环。The lowest ring is an oil distributor ring.最下面的那道环是刮油环。All the rings are slightly rounded on the external top and bottom edges to keep the oil film on the cylinder liner during the running-in period for new piston rings.所有活塞环顶部和底部的外缘都稍有倒角, 以便在新活塞环磨合期间缸套上留有油膜。In order to control thermal stresses, thin wall intensively cooled pistons are used for some types of modern engines.为了控制热应力, 某些现代柴油机采用薄壁集中冷却活塞。In this case, the piston has an internal insert in the piston crown, which serves only to direct the cooling liquid flow and在这种情况下, 活塞头内部有一插件, 它用来对冷却液流导向thereby, to intensify the conventional cocktail shaker effect.由此可增强传统的“鸡尾震荡”效应。The piston rods are bored from the top flange to a point opposite the center of the crosshead.活塞杆从顶部法兰到与十字头中心相对位置处锉孔。Through this bore, a long pipe is inserted which goes nearly to the bottom of the bore.一根长管从此插入接近孔底。The outside diameter of the pipe is less than the diameter of the bore, the result being that an annular space is formed between the piston rod and the pipe.管的外径小于孔的直径, 因此在活塞杆和管子之间形成一个环形空间。The lower end of the piston rod is reduced in diameter to fit a bore in the crosshead, this being secured to the piston rod by a nut.活塞杆的下端直径减小, 插入十字头内孔中, 并用螺帽将十字头与活塞杆紧固。The piston rods are provided with dowel pins to ensure the correct assembly of the components.活塞杆上装有定位销, 以确保各部件的正确装配。On each of the two journals of the crosshead, crosshead shoes are mounted which are guided in the built-in crosshead guides of the engine frame.在十字头两端轴颈处, 各装有十字头滑块。十字头滑块由发动机机架内的一十字头导板导向。The position of the crosshead shoes on the crosshead is determined by dowel pins. The guide shoes are secured to the crosshead by means of tap-bolts.十字头滑块在十字头上的位置由定位销确定, 并用锥头螺栓紧固在十字头上。The crosshead shoes are white metal lined, grooves being cut horizontally in the face of the white metal to ensure an adequate supply of lubricating oil.十字头滑块表面浇有白合金, 为确保提供足够的滑油, 白合金表面开有水平沟槽。The crosshead is short and rigid and the bearings are so constructed that the bearing pressure between the journal and bearing is distributed evenly over the entire length of the bearing.十字头短且坚固, 轴承的结构设计使轴承与轴颈间的承受压力沿整个轴承长度均匀分布。In order to improve the working conditions of the bearings, the bearing pressure is made smaller and the peripheral speed higher in later designs. 为改善轴承工作条件, 在后来的设计中, 减少了轴承承受压力, 提高了圆周速度。The pistons are cooled by oil supplied from the forced lubricating system.活塞由强力润滑系统供给的油来冷却。The cooling oil is admitted through the pipe, from which the oil is led to the cooling spaces of the piston through telescopic pipes or articulated pipes冷却油经管路导入, 经伸缩管或铰接管及活塞杆内的环形空间流进活塞的冷却空间and round the internal pipes of the piston rods. The cooling oil is conducted from the pistons through the internal pipes of the piston rods and ducts in the crossheads, as well as the slotted pipes from which the oil is led to control boxes with sight glasses on the engine.再由活塞经活塞杆内管、十字头中的管道以及开槽管排入发动机上装有观察镜的“控制箱”中。Sealing between the crankcase and scavenging air boxes is achieved by means of the piston rod stuffing boxes, located in the bottom of the scavenging air boxes.曲轴箱与扫气箱之间的密封, 通过位于扫气箱底部的活塞杆填料箱来完成。Each stuffing box is provided with two sealing rings and three scraper rings.每个填料箱都装有两个密封环和三个刮油环。The sealing rings, which are mounted uppermost, are in four parts and pressed together around the piston rods by means of coil springs.密封环装在最上面, 它分为四段, 通过圈簧将其箍紧在活塞杆周围。Connecting rod and main bearings连杆和主轴承The crosshead and crankpin bearings are made of cast steel and each consist of an upper and lower part secured to the connecting rod by means of fitting bolts, the nuts of which are secured.十字头轴承和曲柄销轴承都由铸钢制成, 分成上下两部分, 由紧配螺栓紧固在连杆上。其锁紧螺母是防松的。Compression shims are provided between the bottom end bearing and the palm of the connecting rod. 在下端轴承和连杆端部之间装有压缩比调整垫片。The bearings have white metal bearing surfaces provided with lubrication grooves for the necessary supply of lubricating and cooling oil.轴承面浇有白合金, 并开有油槽, 以提供必要的润滑冷却油。Shims of different thicknesses are inserted between the shells to enable adjustment of the bearing clearances (approx. 0.20-0.30 mm).不同厚度的垫片可插入轴瓦间, 以调整轴承间隙(0.200.30 mm)。The main bearings, which support the crankshaft, each consist of two shells of cast steel with white metal bearing surfaces having lubricating grooves of an appropriate shape.主轴承支撑曲轴, 每道轴承由两片轴瓦组成。瓦背由铸钢制成, 表面浇有白合金并开有适当形状的油槽。The shells are secured by means of bearing caps and studs, the necessary clearance (approx, 0.30 mm) being provided by means of shims of different thicknesses.轴瓦由轴承盖和双头螺栓紧固, 并用不同厚度的垫片调至必要的间隙(约0.30 mm)。All bearings are lubricated from the force-feed lubrication system of the engine,所有的轴承都由发动机的强力润滑系统来润滑the oil being supplied partly through pipes to each main bearing cap and partly to the crosshead, form where the lubricating oil flows through channels to the crankpin bearings.所提供的滑油一部分通过管道流到各个主轴承盖, 一部分流到十字头, 再由十字头通过连杆中的通道流到曲柄销轴承。Crankshafts曲轴The crankshaft is built up, the forged main bearing journal being shrunk into cast steel crank throws (semi-built).曲轴是组合式的, 锻造的主轴颈以红套的方式插入铸钢制成的曲柄臂(半组合式)中。The crank throws are displaced from each other to obtain the same number of degrees between the different crank throws.曲柄相互错开以使不同的曲柄间有相同的夹角。The crankpin journals are provided with large bores for balancing purpose.为了平衡所需, 在曲柄销轴颈上钻有较大的孔。B. Multiple Choice选择题Questions 1-5 arc based on paragraphs 1-4根据课文第1-4段回答问题1-51. All the rings are slightly rounded on their external top and bottom edges to keep the oil film on the cylinder liner during for new piston rings. .所有活塞环顶部和底部的外缘都稍有倒角，以便在新活塞环_将油膜留在缸羹 答素:AA. the running-in period 磨合期间 B. the running process运转过程C. the gas exchange process 换气过程 D. the boiler firing锅炉发火2. The position of the piston parts in relation to each other machine-turned recesses and in the crown. 活塞各部件相互间的位置由活塞头上车削的凹槽和一来固定。答素.CA.a mark标记B.a bolt螺栓C.a dowel pin定位销D.a missing tool测量工具3. The lowest ring of a piston is 活塞最下面的那道环是_。答素:CA. a coil spring 圈簧 B. a sealing ring密封环C. oil distributor ring 布油环 D. a main seal ring主密封环4. The piston rods are bored from the top flange to a point opposite the center of 活塞杆从顶部法兰到与_中心相对位置处键孔。答案;DA. the main bearing 主轴承 B. the crankshaft曲轴C. the dowel pin 定位销 D. the crosshead十字头5.The lower end of the piston rod is reduced in diameter to fit a bore in the crosshead, this being secured to the piston rod by 活塞杆的下端直径减小，插人十字头内孔中，并用.将十字头与活塞杆紧固。答素:A.A. a nut螺母 B. a bolt螺栓C. a dowel pin定位销D. a spring弹簧Questions 6-10 are based on paragraphs 5-9. 根据课文第5-9段回答问题6-106.The position of on the crosshead is determined by dowel pins. _在十字头上的位置由定位销确定答案DA. the grooves 凹槽 B. the piston rings活塞环C. the piston skirts 活塞裙 D. the crosshead shoes十字头滑块7.The crosshead shoes are lined十字头滑块表面浇有_。答素.B.A. chromium steel 铬钢 B. white metal白合金C. alloy steel .合金钢 D. white silver白银8.The cooling oil is usually supplied to the pistons by means of the crosshead. 冷却油通常经与十字头相连的-供给活塞。答素.CA. injectors 喷油器 B. pumps.泵C. telescopic pipes 伸缩管 D. guide ways.导板9.The pistons are cooled by oil supplied from . 9.活塞由供给的油来冷却。答案DA. the open system 开式系统 B. the F W cooling system淡水冷却系统C. the S W cooling system.海水冷却系统 D. the forced lubricating system强力润滑系统10.The sealing rings are in four parts and pressed together around the piston rods by means of . 密封环分为4段，通过将其箍紧在活塞杆周围。答案CA. nuts螺母 B. bolts.螺栓C. coil springs圈簧 D. stuffing boxe填料箱sTask 2 Vocabulary and Structure任务2词汇与结构A. Technical Terms A.专业术语Translate the following into Chinese. 将下列词组译成汉语。1.活塞裙 2.热应力 3.十字头滑块 4.带头螺栓5.填料箱 6.紧配螺栓 7.曲柄销 8.轴承间隙1.piston skirt 2.thermal stress 3.crosshead shoe 4.tap-bolt 5.stuffing box 6.fitted bolt 7.crank journal 8.bearing clearance B.Active Words.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。roundboreboltcaulkinsertshrinkdisplace1.The piston rods are from the top flange to a point opposite the center of the crosshead.bored活塞杆从顶部法兰到与十字头中心相对位置处铿孔。2.Shims of different thicknesses are between the shells to enable adjustment of the b