供油提前角对柴油机性能影响毕业设计.doc

燃油喷油压力提高对柴油机燃烧的影响分析 摘 要 柴油机在各种动力机械中之所以占优势的主要原因是经济性好。近些年来，随着柴油机技术的发展，其经济性仍然在不断地提高。为了改善经济性，采取了多种措施，例如：改变喷油压力，提高喷油压力和喷油速率，缩短喷油持续期；优化燃烧室形状，改善换气过程；采用高效率增压器，创造出各种形式的增压系统；采用包括电子调速器，电子喷射系统在内的电子控制系统；减少内摩擦和提高机械效率等。而燃油系统喷油时刻对柴油机的性能和排放起着至关重要的影响。通常对经济性和烟度要求最佳的柴油机所需的喷油压力较大；而大量实践又表明，降低排气中NOx含量最有效的办法是延迟喷油，即减小喷油压力，使燃烧拖后在较低的温度下进行。因此存在最佳喷油提前角的问题。 通过AMESim 软件建模, 对高压共轨喷油器进行模块化分析和仿真研究。将模拟结果与实测结果进行对比, 两者变化趋势比较吻合, 从而验证了模型的准确性。然后通过改变关键结构参数, 探讨了该喷油器主要结构参数对喷射过程的影响, 确定了保证系统稳定性的结构参数的选取原则, 对高压共轨电控喷油器的设计具有一定的参考价值。  分析喷油压力变化对柴油燃料发动机排放的影响。试验结果表明:喷油压力提前，柴油燃料的有效燃油消耗率降低。随着喷油压力减小，燃料滞燃期缩短，喷油压力为15oCA时，燃料的燃烧持续期最短，增加或减少喷油压力都将延长燃烧持续期。喷油压力变化对柴油燃料发动机的排放有较大影响，推迟供油，燃料的烟度排放和CO排放增加，NOx排放与HC排放降低。 关键词:柴油机；喷油压力；排放特性 Effect of Fuel Supply Advance Angle on an internal Combustion Engines Abstract In various mechanical power of diesel engine is the main reason is the dominant economical. In recent years, along with the development of technology, the diesel engine is still in improving efficiency. To improve the efficiency and adopted various measures. For example: change injection advance, improve the injection pressure injection rate and injection, shorten the duration, Optimized chamber shape, improve ventilation process, Using efficiency, create the supercharger turbo systems of various forms, By including the electronic governor, injection system, electronic control system, Reducing friction and improve mechanical efficiency, etc. And fuel system of diesel injection time of performance and emission plays a crucial influence. Usually the economy and to meet the requirements for the best diesel injection advance greatly, But a lot of practice and suggests that reducing exhaust in the most effective way to content NOx injection, which is the delay reduced injection advance, burning up under the low temperature. Therefore there are best injection Angle. Through the analysis of test, diesel injection advance changes of diesel fuel combustion emissions. Test results show that the injection advance in advance, With