重载履带车辆发动机再制造技术分析与评估体系探讨 毕业论文外文翻译.doc

英文文献及翻译investigation of remanufacturing technology and evaluation system of heavy duty caterpillar engine1 introductionwith the resource increasingly drying up and the environment contaminative pricking up, the significance of continual development was understood gradually by people. the remanufacturing engineering is came into being and became one new engineering subject as the resource requirement was increasingly went up by human being. and it is regarded importantly by all the countries and become one important technology support to carry out the strategic of continual development1,2.owing to the mal-conditions of operating and the high reinforcement, heavy duty caterpillar engines have a very short service life comparing with the civil vehicle. it is the unequal-life of the engines parts and working surfaces that results in the failure of some parts and working surfaces and the engines goes to out-of-service. short service life of engine and unconformity with the life cycle of vehicle had become a bottleneck to the maintenance in the armored cavalry3.it is urgent for the ensuring and maintaining of armored equipment to start the remanufacturing of armored vehicle engine based on high technology for prolonging its service life. notable benefit in economy and military fairs will be gained by the same service life with the vehicle after remanufacturing of the engine. 2 feasibility analysisthe manufacturing technology used in the heavy duty caterpillar engine is following the old technology of the soviet times, which have 50 years up to now. and a great many new technique and material have occurred in these 50 years.the suface engineering technology, which adopting many surface intensify technology to consolidating the surface of material and getting the high wearability, was developed from the 1980s. it provides a technology base to remanufacturing the equipment engine4. now, the employ life-span of civilian engine have reached at 800010000h as using the new technology, new material and new surface treatment technology. according to the “cannikin theory” of product life, it will prolong the life-span of engine as long as increasing the length of those shortest board, which can influence the performance of engine, namely, prolonging the life-span of key friction mate for engine such as cylinder/piston, bending axis/tile, camshaft/valve adjusting set5. all these provides the sustain of theory and practice.therefore, it is feasibility both in theory and technology to remanufacturing the equipment engine from the above analysis.3 remanufacturing of heavy duty caterpillar engine3.1 conception of remanufacturing for heavy duty caterpillar enginenot all the products are suitable for remanufacturing. heavy duty caterpillar engine has an obviously difference in designing, fabrication process , working condition and service life with civil vehicle engine. for example, the friction surface has a same life to the main body of engine (equal-life designing as deutz engine)and most parts have wear out after an overhaul life of a civil vehicle engine, while for heavy duty caterpillar engine, it is another case that many parts have an ability to service more long, some are even in the better state. so the remanufacturing of heavy duty caterpillar engine is different from the civil in the goal, technique project and method6.generally speaking, the fixed parts such as case, housing and bearing block have a long life while the service life of moving parts is shorter and the friction surfaces have shorter life than the parts which deliver the torque. it is the unequal-life of parts and their working surfaces which result in the failure of some parts/working-surface and out-of-service of equipment as a whole. in other words, the unequal-life of parts and their working surfaces provides a material base for remanufacturing7.because of the long terms of design and service, remanufacturing is an upgrade procedure for heavy duty caterpillar engines. based on the prototype version, many advanced technology and new parts are adopted to promoting some key performances of the old products greatly, i.e. the remanufacturing of engines is coincident with the society of resource-saving and green environmental protection. the goals of heavy duty caterpillar engine remanufacturing are as follows: based on the systematic analyzing to engine, improve the wearing and friction state of engines fricative pairs by the surface strengthening of key parts applying the multi-surface engineering technology, find a more suitable material with matching surface modified nature to reduce the attrition of working surfaces, and finally double the service life of the engine. 3.2 key remanufacturing techniquea lot of key techniques applied in remanufacturing come from the up-to-date achievement of science and technology such as advanced surface technique, micro and nano-coating and wear-resistance self-recovery material and technique, renovation heat treatment technique, molding technique of remanufacturing blank and up-date of outdated products. the main classification of key technology for remanufacturing was summarized as fig.18.advanced surface technique and composite surface techniquerepairing heat treatmenttechniqueremanufacturing celerity figuration techniqueemergence celerity maintain techniqueremanufacturing special machining techniqueremanufacturing mechanism machining techniqueequipment alteration and capability upgrade techniquenano coatings and nano material restore techniquekeyremanufacturingtechnologyfig.1 classification of key technology for remanufacturingthe key technique of remanufacture engineering includes many types, in which the advanced and compound surface techniques play an important role in repairing and strengthening the failure surfaces of waste and old parts. various surface coating techniques are widely used because the attrition wear and corrosion of waste and old parts appear mainly on the surface. based on micro and nano-materials, for micro and nano-coating and wear-resistance self-recovery technique, a special coating technology can be used for reinforcing surface with promotion of performance, or self-recovery technology forming film at affected position of friction surface guided by tribochemistry to solve the problems in remanufacturing. the holistic performances of parts can be recovered from initialization of inner construction by renovation heat treatment technique. besides the technique mentioned above, normal and some special machinery are also used in remanufacturing engineering.3.3 general planningunlike traditional overhaul, remanufacturing completes a progress of upgrading for promotion of performance and service life against the engine out-of-service.measured and analyzed systematically, the main parts of engine were sorted into four classes by their status: used without any treating, remanufactured, new and upgrade. the degree of wear was analyzed for the parts used continuously and remanufactured, and the service life of the parts was evaluated by life predicted method. the remanufacturing process was according to the new parts productive standard and the key parts were reinforced by means of multi-surface engineering technologies such as laser-quenching, ion-implant, ion-sulfurizing at normal temperature, magnetron sputtering, supersonic plasma spray, nanometer brush plating, nitriding, boriding, nanometer oil additive, intellectual oil infiltrating for lubrication ,and plasma submerge injection.the procedure of remanufacturing to engine is stepped as follows: first, find out the main parts which have a strong effects to engine service life such as cylinder/rings, crankshaft journal/bearings bush on referencing the experience of repair factory; then by analyzing of work condition, materials, fabrication process and the normal failure form of these parts, basic test researching would be carried out in laboratory using some new material and craft especially the advanced surface engineering; the third thing to do is the bench test to compared various combinations of different methods. to some extant, the remanufacturing of these key parts determines success or not of remanufacturing to whole engine. some other problems as scale deposit, carbon deposit, failure of sealing should be taken into consideration owing to the prolonged engine service life. as for the remanufacturing times (cycles) of main structural parts, it needs to be studied specially in fatigue life.3.4 treatment of main friction pairsbecause of particularity in use of heavy duty caterpillar engine, the remanufacturing program has its uniqueness and different technical measures would be used for different pasts. as the first time to remanufacture to the tank engine, we make our focus on the main key friction pairs which have s strong affection on the service life of engine while untreated new products were used for accessories section like turbocharger, oil pump and water pump.3.4.1 crankshaft and connecting rod mechanismrecovering the size of journals by nano-electronic brush plating;anti-carbon deposit and tbs coat were used synchronously at piston crown to reduce heat transfer from piston and improve the working condition of first ring groove while the piston skirt was plasma sprayed with al alloy to recover size and strengthen.at the friction surface of gas ring mo layers were sprayed to reduce the coefficient of friction and abrasion of cylinder with rings.a self-lubricating film was gained at inner surface of cylinder by medium-frequency quenching and ion sulfurizing at normal temperature. supersonic plasma spray was applied at outside surface of cylinder for reducing cavitation wear.3.4.2 air distributing mechanismsulfurizing at journal of camshaft to reduce the friction and wear.the coefficient between valve and guide was reduced by ion sulfurizing at normal temperature and nano-addition agent in the oil.3.4.3 engine bodyusing supersonic plasma spray, the surfaces were strengthened and recovered in size for engine case, bearing saddle bore.4 design of evaluation criterion systemit is necessary that the stability of engine performance, reliability and anti-resistance abradability be verified by bench test to evaluate the processing set-up and technical measure used in tank engine remanufacturing. the standards aim at the change of engine performance and the state of main parts, i.e. the engines performance become bad or not, the abrasion of the main parts is overproof or not after running at test bed for 1000 hours guided by warrant test program.the tests should be completed are as follows: full load characteristic test, constant speed characteristic test at rated speed, lub-oil consumption measure, lub-oil sample optical spectrum analysis, reliability test, engine vibration measure. besides the items specified in the chinese standard and military standard, the circulate flow measurements of oil and cool water were done for judging the states of oil pump and water pump indirectly, the vibration of the crankcase was measured to monitor the fit clearances of piston/cylinder and main journal/bearing. the performance index measured must be converted first to number at the standard atmospheric condition by chinese standard and then the change rates of performance reflecting engine technical statues be analyzed such as rated power, brake specific fuel consumption(bsfc), smoke, and specific lub-oil consumption. based on the research to test specifications of civil vehicle engine and combining the working condition of tank engine, we take the criterion as follows: the test will be considered as meeting the demands of engine performance if the rated power reduces not more than 4%, lub-oil specific consumption increases not more than 25% and the bsu(bosch smoke unit) increases not more than 10% after the reliable test.as to the abrasion of engine parts, metallographic analysis and size measuring should be done for the parts remanufactured such as piston, cylinder, crankshaft, valve, camshaft. if the sizes of main parts are not overrun and there are not breaking-off on the working surface of bearings, we can say that the remanufacturing technique is successful.5 conclusionintroducing the significance of remanufacture to tank engine, the author analyzed the service of tank engine and the failure of main parts first, then pointed out that the remanufacture for heavy duty caterpillar engine has its special content and style to normal civil vehicle engine. the applying of remanufacture technique is to promote the service life of tank engine by using modern surface engineering. after introducing the remanufacture technique program and measure in detail, a preliminary criterion was offered to judge if the remanufacture is success or not for the tank engine and it is beneficial to the building of engine remanufacture criterion system.references1xu binshi, li renghan, liang xiubing. the development of green remanufacturing engineering. china surface engineering. 2001, 14(2): 1-4.2xu binshi, ma shining, liu shican. the remanufacturing engineering of 21 centuriesj. chinese mechanism engineering. 2000,11 (1):36-38.3 liang zhijie , xu binshi,et al.discussion and feasibility analysis of remanufacturing technology for armored equipment engines, j china surface engineering. 2006 (19)5: 89 -91.4 liu qian,dai qingrong .present condition of again manufacture of the automobile engine and its crucial techniquej. plant maintenance engineering beijing.2003 no.2 :9-105zhang ping, liang zhijie, wang haijun. study on remanufacturing technology of cylinder liner/piston ring for armored equipment engine. china surface engineering. 2006 (19)5: 92 -95.6 zhang guoqing , jing xuedong , et al. assessment on remanufacturability of the automobile engines j. china mechanical engineering. beijing. 2005,(16)8:739-7427xu binshi, ma shining, liu shican. application od surface engineering and remanufacturing engineeringj. material protection. 2000,33 (1):1-5.8zhu shaohua, liu shican, zhusheng. discussiong of connotation and subject structure for remanufacturing engineering. china surface engineering. 2001, 14(2): 5-7.重载履带车辆发动机再制造技术分析与评估体系探讨1 前言随着资源的日益枯竭和环境污染的加剧，人们逐渐认识到可持续发展的重要意义，并不断探索实现可持续发展的手段。再制造工程就是在人类对资源要求的日益增长和对环境保护的迫切需要的情况下形成的一门新的工程学科，且因其巨大的资源、环境、社会效益而受到世界各国的重视，成为落实可持续发展战略的重要技术支撑1，2。再制造工程是以装备全寿命周期设计和管理为指导,以装备实现性能跨越式提升为目标,以优质、高效、节能、节材、环保为准则,以先进技术和产业化生产为手段,对装备进行修复和改造的一系列技术措施或工程活动的总称。再制造是零件水平上的制造,零件的附加值得以保留,具有相当的经济效益,有利于环保和可持续发展。汽车零部件的再制造是研究最早的领域,已经形成了相当规模的产业。对汽车再制造而言,发动机的再制造占主要的份额,国内许多厂家如济南复强动力公司和上海大众等针对发动机的再制造做了大量的研发工作,可以预言再制造发动机在未来的汽车发动机市场上所占的比例一定会越来越高3。目前世界范围军用重载履带车辆绝大多数以柴油机为动力,其可靠性直接影响重载履带车辆的机动性能和战斗力。由于强化程度较高和工作条件恶劣, 重载履带车辆发动机的使用寿命普遍较短,远低于一般民用车辆。重载履带发动机的寿命短以及与车体寿命周期不一致已经成为制约装备保障维修的瓶颈。因此,对重载履带车辆发动机进行基于高科技的再制造,延长其使用寿命,已成为装备保障、维修工作的一个迫切任务。再制造后,发动机的使用寿命力争达到与车体相同,具有相当的经济效益和军事效益。2 可行性分析目前使用最多的重载履带车辆发动机主要沿用的是上世纪50年代苏联的制造技术，至今已有50余年的时间。在当今这个科学技术发展日新月异的年代，在50年的时间里出现了大量的新技术、新材料和新工艺。80年代以来国际上出现的表面工程技术，通过各种表面强化和改性工艺，能够使零件表面得到充分的强化，获得整体材料无法达到的耐磨损、耐腐蚀和耐高温性能，为材料表面强化和改性提供了有效的技术手段；这就为装备发动机的再制造奠定了可靠的技术基础4。目前，民用发动机由于广泛采用新技术、新材料和新的表面处理方法，其使用寿命已经达到了800010000h。如德国出产的道依茨发动机，其使用寿命已经超过了10000 h，其摩擦副与发动机壳体完全实现了等寿命设计。同时，50年后的今天，现代的装备再制造工程理念、润滑油纳米自修复添加剂技术，为发动机大修寿命的大幅度提升提供了良好的机遇。根据产品寿命的“水桶理论”，只要提高影响发动机性能的最低几块板的长度，即延长发动机关键摩擦副的使用寿命，如缸套/活塞环、曲轴/轴瓦和凸轮轴/气门调整盘等摩擦副，就可以延长发动机的寿命5。这为装备发动机的再制造提供了理论和实践依据。因此，通过以上分析可知，对装备发动机进行再制造，在理论、技术上都是可行的。3重载履带车辆发动机再制造技术分析31重载履带车辆发动机再制造的理念不是所有的产品都适合再制造。与民用车辆发动机相比，重载履带车辆发动机从设计理念、制造工艺、使用条件、寿命等方面均有很大不同。例如同样是到了大修期，民用车辆发动机摩擦副的使用寿命与发动机本体基本实现了等寿命设计（如德国的道依茨发动机），多数零件已经严重磨损，“寿终正寝”。而重载履带车辆发动机到其大修期时，往往有很多零件还具备继续服役的能力，个别的甚至正处在良好的状态。因此对完成一个服役周期（大修期）的重载履带车辆发动机进行再制造，无论目的、技术方案还是技术手段等都与一般民用发动机的再制造有所不同6。在装备零件中，通常固定件的使用寿命长，如箱体、支架、轴承座等，而运转件的使用寿命短。在运转件中，承担扭矩传递的主体部分使用寿命长，而摩擦表面使用寿命短。这种各零部件的不等寿命性和零件各工作表面的不等寿命性，往往造成装备中部分零件以及零件局部表面的失效，而导致装备整体的报废。每个零件的各工作表面的使用寿命不相等，为再制造的实施提供了物质基础7。对重载履带车辆发动机而言，由于其设计和服役周期长，再制造还是一个升级改造的过程。以旧机型为基础，不断吸纳先进技术、先进部件，可以使旧产品的某些重要性能大幅度提升，符合建设资源节约型社会和绿色环保的要求。因此，对重载履带车辆发动机再制造的目标就是：在对发动机系统考虑的基础上，应用多种复合的表面工程技术对关键零部件进行表面强化，改善发动机内摩擦副的摩擦磨损状态，寻找最佳的材料及表面改性匹配以最大限度地减少摩擦副之间的磨损，发挥再制造技术的后发优势，将发动机使用寿命提高一倍。32再制造关键技术装备再制造工程是通过各种高新技术来实现的。在这些再制造技术中，有很多是及时吸取最新科学技术成果的关键技术，如先进表面技术、微纳米涂层及微纳米减摩自修复材料和技术、修复热处理技术、再制造毛坯快速成形技术及过时产品的性能升级技术等，其主要分类如图1所示8。先进表面技术和复合表面技术修复热处理技术再制造快速成形技术应急快速维修技术再制造特种加工技术再制造机械加工技术装备改造和性能升级技术纳米涂层及纳米材料自修复技术再制造关键技术图1 再制造关键技术的分类再制造工程的关键技术所包含的种类十分广泛，其中主要技术是先进表面技术和复合表面技术，主要用来修复和强化废旧零件的失效表面。由于废旧零部件的磨损和腐蚀等失效主要发生在表面，因而各种各样的表面涂敷技术应用得最多。微纳米涂层及微纳米减摩自修复技术是以微纳米材料为基础，通过特定涂敷工艺对表面进行高性能强化和改性，或应用摩擦化学等理论在摩擦损伤表面原位形成自修复膜层的技术，可以解决许多再制造中的难题，并使性能大幅度提高。修复热处理是一种通过恢复内部组织结构来恢复零部件整体性能。除上述这些有特色的技术外，通用的机械加工和特种加工技术也经常使用。再制造毛坯快速成形技术是根据零件几何信息,采用积分堆积原理和激光同轴扫描等方法进行金属的熔融堆积。除上述这些有特色的技术外,通用的机械加工和特种加工技术也经常使用。33再制造技术方案装备再制造是针对已到服役期的发动机进行的，其内容不是传统的大修，而是提高性能延长使用寿命的升级改造过程。以系统的观点，对发动机的全部零部件进行检测和分析，根据各自的技术状况分成四类：直接利用件、再制造件、新品件、新品强化件，首先对直接利用件和再制造件进行磨损状态分析，并利用寿命预测方法对每一部件进行寿命评估，然后按照新品制造的标准来进行再制造，并综合采用多种复合的表面工程技术对关键零部件进行重点强化处理，采用的关键再制造技术包括：激光淬火、离子注入、低温离子渗硫、磁控溅射、超音速等离子喷涂、纳米电刷镀、渗氮、渗硼、纳米添加剂、智能化渗油润滑处理、等离子浸没注入等技术。发动机再制造具体步骤为，首先根据以往大修厂的经验，确定影响发动机寿命的主要零件，如缸套与活塞环、曲轴轴颈与主轴瓦和连杆轴瓦等，针对其工作条件、材料、制造工艺、一般破坏失效形式等进行深入的分析，结合新材料、新工艺特别是先进的表面工程技术，先在实验室使用样件进行基础试验研究，然后选择若干种方案组合配套，最后分别在发动机的不同气缸和轴颈实施，在发动机台架试验后再检查分析各方案的优劣。应该说这些关键零部件的再制造成功与否决定了整个发动机再制造的成败。对于发动机其他的摩擦副，如凸轮轴与轴承、气门杆与气门导管、传动齿轮轴与轴承等，根据其服役工况和磨损形式，采取适宜的表面技术处理，对于附属配件（水泵、机油泵、低压柴油泵和涡轮增压器等）进行局部强化处理，以保证其能够满足延长整机寿命的要求。延长发动机使用寿命后可能出现的其它情况如水垢、积碳、密封件老化等也要采取有针对性的措施。至于主要结构件能够再制造的次数，属于材料疲劳周期范畴的问题，是一个基础课题，需要进行专项研究。34 发动机关键摩擦副的再制造处理重载履带车辆发动机因其用途的特殊性，决定了其再制造也具有一定的独特性，不同的部件采取不同的技术措施。由于这是首次对重载履带发动机进行的再制造，焦点集中在影响发动机使用寿命的几个关键摩擦副上，因此对增压器、机油泵、水泵等件没有进行再制造处理，基本采用新品，待对其寿命规律进行深入研究后再考虑采取相应的技术改进措施。341 曲柄连杆机构采用纳米电刷镀技术进行曲轴再