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1、http:/ http:/ 柴油机喷油系统的排放控制技术研究摘要：柴油机净化的关键是如何有效地消除NO和微粒碳烟的生成量。文章从喷油系统出发，提出了改进排放的五种切实可行的方法，具有明显的现实意义。Abstract: purifying diesel engine is the key to how to effectively eliminate the NO and carbon particles in the smoke generation. Article embarks from the fuel injection system, and puts forward the im
2、proved emissions of five kinds of practical methods, has obvious practical significance.关键词：柴油机；排放控制；措施Key words: diesel engine; Emission control; measures柴油机的有害排放取决于柴油机混合气形成及缸内燃烧过程，而这些归根到底是由喷油、气流、燃烧系统以及缸内工作特质的配合所决定的。柴油机净化的关键，是如何有效地消除NO和微粒碳烟的生成量。恰恰这两项排放物的生成规律常常是互相矛盾的。因此，任何一个单项措施总有它的负面影响。人们总是在采取某项措施的
3、同时，应用另一项措施来加以补救和平衡。最后，常常是多项措施的综合应用，才使排放性能达到一个新的水平。柴油机是一个多性能、多工况、多因素综合影响的统一体，再加上各种各样的排放净化措施，如何进行优选、折中和综合控制是一个极为困难和复杂的问题。柴油机的电子控制和综合管理是有效解决这一问题的最佳途径，也是使各种机内净化措施得以充分发挥效用的保证。在所有净化措施中，喷油系统的改进无疑是最为重要的环节。The harmful emissions of diesel engine depends on the mixture formation and combustion process in cylin
4、der of diesel engine, which are in the final analysis is by injection in cylinder, air flow, combustion system and working characteristics of cooperation. Purification of diesel engine key is how to effectively eliminate the NO and carbon particles in the smoke generation. Just this two emissions ge
5、nerated rules are often contradictory. Therefore, any single measure always has its negative effects. People are always in a measures at the same time, application of another steps to remedy them and balance. Finally, often is a comprehensive application of measures to make emissions performance to
6、a new level. Diesel engine is more than a performance and working condition and factor synthesis influence continuum, plus various emissions purification measures, how to carry out optimization, compromise, and integrated control is an extremely difficult and complex problem. Diesel engine electroni
7、c control and integrated management is the best way to solve this problem, effective also allows various internal purification measures to give full play to utility. Of (among) all the purification measures, improve the fuel injection system is undoubtedly the most important link.车用柴油机中常用的机械燃油喷射系统有两
8、大类，直列泵系统和转子分配泵系统。直列泵系统包括直列多缸泵、单体泵和泵喷嘴系统，多用于大、中型车用柴油机上。转子分配泵系统有端面凸轮驱动的VE泵系统，和内凸轮驱动的径向对置柱塞系统，多用于轻型客车和柴油轿车的小型高速柴油机上。上述各系统都是应用柱塞往复运动、脉动供油的方式工作。以下是五种控制柴油机排放的具体措施：Automotive diesel engine that is commonly used in mechanical fuel injection system has two types, inline pump system and the distribution of th
9、e rotor pump system. Inline pump system including inline multi-cylinder pump, single pump and the pump nozzle system, used in large and medium-sized vehicle diesel engine. Distribution of the rotor pump system has end CAM driven VE pump system, and the radial opposed piston CAM driven system, more f
10、or passenger cars and diesel cars, small high-speed diesel engine. The above systems are application of plunger reciprocating motion, and pulse oil supply work. Here are five kinds of diesel engine emission control measures:一、推迟喷油提前角降低NO排放A, delay the injection advance Angle to reduce NO emissions喷油
11、提前角是喷油始点早于汽缸压缩上止点的角度。柴油机都要求喷油提前，这是因为从喷油到着火有一段滞燃期，为保证实际燃烧放热中心能接近上止点，避免燃烧拖后，经济性下降，所以喷油要提前。单从动力、经济性角度出发，最佳提前角随转速上升而增大；随负荷加大而略有增加。车用柴油机因为在宽广的转速范围内工作，所以有专设的转速自动提前装置来满足此要求。同一工况，若提前角改变，会使滞燃期改变。一般推迟喷油时，因初期喷油更接近上止点，故缸内压力、温度较高，滞燃期缩短。其结果是滞燃期的预混喷油量减少。当然，若喷油太迟，使滞燃期挪到上止点之后，则缸内压力、温度未必上升。这种情况一般难于碰到。预混燃烧阶段是影响NO排放最重要
12、的时期。预混油量及混合气量的减少将使速燃期中压力、温度上升程度降低，从而大大减少NO的排放量。同时，由于压力升高率的下降，噪声也大大降低。因此推迟喷油提前角这一措施，是最早应用的有效降低NO排放和噪声的对策。推迟喷油，直喷机的NO大幅下降，而间接喷射式涡流室柴油机的下降幅度则小一些。但是喷油过迟，则燃油消耗率和烟度都会恶化，对CO和HC也有不利影响。油耗和烟度的恶化是喷油推迟，燃烧跟着推迟以及缓燃期油量增加，燃烧时期也拉长的必然结果。早期控制排放的措施不多，为了排放达标，不得不牺牲经济性能。近期已可通过提高喷射压力等多种办法来综合解决这一问题。Fuel injection advance An
13、gle is injection starting point is earlier than the check point on the cylinder compression Angle. Diesel engines require injection in advance, because from the oil to the fire for a period of ignition delay period, in order to ensure the check point on the actual combustion exothermic centre close
14、to avoid burning after the economy fell, so injection in advance. Single from the perspective of power, economy, the best advance Angle increases with rising speed; A slight increase with the load increasing. Automotive diesel engine because of working within a wide speed range, therefore have set u
15、p automatic speed device in advance to meet this requirement. The same working condition, if the advance Angle change, change can make the ignition delay period. General delayed injection, because the initial injection closer to the top dead center, consequently higher pressure and temperature in cy
16、linder, shorten the ignition delay period. As a result, the ignition delay period of premixed fuel injection quantity is reduced. , of course, if the oil is too late to make on the ignition delay period to check point, the pressure and temperature in cylinder may not rise. It is difficult to encounter in general. Premixed combustion phase is NO emissions the most important period. Less premixed oil and mixed gas wil
