柴油机与其它类型的发动机相比,在油耗和耐久性上具有显著的优点。然而,近来柴油机对环境的影响已成为日益严重的问题,且阻碍了柴油机的发展。在保持柴油机的燃油经济性及二氧化碳排放小的优点的同时,又要满足严格的排放法规,燃油喷射系统是最重要的关键之一。 研究表明,通过应用燃油预喷射的技术,在很大程度上既能降低直喷机的NO_x和颗粒排放,又能改善燃烧噪声。另外,它不仅保持了柴油机的低油耗和独特性能,而且还证明了适应环境要求的目标的潜能,而这二点是与降低二氧化碳的排放直接有关的。所有重要的环境因素都受燃油喷射系统的很大影响,它无疑将在未来柴油机的发展中起重要作用。 本文描述了通过控制燃油喷射速率和预喷射来改善燃烧和排放特性的可能性。这些结论是通过应用具有先进的液压性能的实验喷射系统,做了大量试验分析而得到的。而且,还揭示了如何进行预喷射以达到降低排放和燃烧噪声。最后,讨论了通过改变这些喷射系统的参数来优化发动机性能的潜力。 Diesel engines have significant advantages over other types of engines in terms of fuel economy and durability. However, the environmental impact of diesel engines has recently become an increasingly serious problem that hinders the development of diesel engines. While maintaining the advantages of diesel fuel economy and low carbon dioxide emissions, as well as meeting stringent emission regulations, the fuel injection system is one of the most important issues. The research shows that by applying the technology of pre-injection of fuel, the NO_x and particle emission of the direct injection machine can be reduced to a great extent, and the combustion noise can be improved. In addition, it not only maintains the low fuel consumption and unique performance of diesel engines, but it also proves the potential of meeting the environmental requirements of the two points directly related to the reduction of carbon dioxide emissions. All important environmental factors are greatly affected by the fuel injection system, which will undoubtedly play an important role in the future development of diesel engines. This article describes the possibility of improving combustion and emission characteristics by controlling fuel injection rate and pilot injection. These conclusions are obtained through a large number of experimental analyzes by using experimental jetting systems with advanced hydraulic performance. What’s more, it shows how pre-injection can be done to reduce emissions and burn noise. Finally, the potential for optimizing engine performance by changing the parameters of these injection systems is discussed.