【作者】 姚光荣；

【导师】 吕林；

【作者基本信息】 武汉理工大学 ， 轮机工程， 2004， 硕士

【摘要】 在大气污染中，汽车尾气排放所造成的污染占60～70％。柴油机的主要排放物是NOx与颗粒的排放。因此柴油机面临的最大发展困难就是，必须降低其NOx与颗粒的排放量。利用进气道喷水技术能够大幅度降低NOx排放量，同时具有节能的作用。 NOx生成的首要条件是高温。氮和氧的化合必须在高温条件下才能进行。所以，只要降低气缸内的温度和局部高温点的温度，就能明显降低NOx的生成量和排放量。水可以利用自身潜热大的特点吸收热量而汽化成为过热蒸汽，从而降低缸内燃烧温度。同时在高温条件下，水蒸汽参与燃烧，部分水分子与未完全燃烧的炽热的炭粒发生水煤气反应，形成可燃性气体，从而减少了火焰中的炭粒，提高了油的燃烧程度，改善了燃烧状况，提高了油的燃烧效率。 本文作者课题组针对国产4135G型柴油机，自行开发出一种进气道喷水技术，同时设计出一套进气道喷水系统。在柴油机上应用该技术非常简单，不需要对柴油机结构做任何改变，只需在进气总管前安装一套喷水系统。系统采用电子控制技术可以很方便在有水与无水模式下切换，同时在有水模式时能够调节水量。本文利用该系统对4135G型柴油机进行试验，得出了良好结论。 本文详细介绍了喷水系统总体方案、台架试验及喷水系统的优化方向。喷水系统包括雾化系统及水量控制系统，其中雾化系统包括空气源(空气压缩机)、水源(加压水)及气—雾喷嘴；水量控制系统包括比例调压阀、控制电路部分。试验包括敏感性试验、排放测试试验、油耗试验及燃烧压力曲线测试试验。试验结果表明，不同喷水量能够明显降低NOx排放，燃油经济性也有改善的趋势。喷水系统优化方向的介绍包括最佳水量方案(不同工况下喷入不同水量)确定原则和闭环系统的设计方案。更多还原

【Abstract】 The pollution due to emissions of automobile is the main cause of atmospheric pollution. The crucial discharges of diesel engine are NOx emissions and (PM) particle material emissions. So lowering NOx and PM emissions is the ultimate handicap along developing of diesel engines. Utilizing technology of water injection into intake ports can both lower largely NOx emissions and economize oil.High temperature is the chief matter resulting in produce of NOx. Only if we would find a kind of way to lower combustion temperature,’the NOx emissions will be reduced evidently. Because of its great latent heat, water can absorb heat and boil away, so as to lower combustion temperature. Meanwhile in the condition of high temperature, water vapors can participate in combustion. Water gas reaction will happen, which will reduce carbon particle in flame, and reform combustion performance, so improve combustion efficiency.The article developed a kind of technology of water injection into intake ports for 4135G diesel engine, meanwhile designed a suit of water injection system. It can be applied simply to diesel engine, because it is unnecessary to change engine’s configuration. It only needs a set of water injection system of installation before intake pipe of diesel engine. The running mode of engine can be switched between water injecting mode and no-water mode by the system. And quantity of water will be adjusted by the system when engine works in the water injecting mode. A favorable conclusion is educed through experiment.The article introduced in detail the scheme of water injection system, test-bed and the direction optimizing the system. Water injection system includes pulverization system and controlling system of water quantity. Pulverization system includes air resource, water resource and gas-mist nozzle; controlling system of water quantity includes booster, controlling circuits. Water quantity is decided by hydraulic pressure and gas pressure. Tests include sensitive test, test of emissions, oil consuming test, and combustion pressure curve test. It is showedthat NOx emissions can be reduced evidently. The direction of optimizing system includes optimal water quantity and design of closed loop controlling system.更多还原