米勒循环对船用低速柴油机性能影响的仿真研究

针对节能减排对船舶行业所具有的重要意义，对应用米勒循环技术的某型船用低速柴油机进行了模型验证与仿真计算，分析了米勒循环强弱对柴油机性能的影响，给出了米勒循环强弱对柴油机缸内压力、温度、放热率及NOx排放的影响规律，并对船用低速柴油机的综合性能进行了评估。研究结果表明：米勒循环强弱对柴油机缸内温度及放热率具有较大影响，控制米勒循环强弱能够显著降低NOx的排放，排气阀每晚关10oCA, NOx生成量降低6%-7%，当米勒循环增加到一定程度时，继续加强米勒循环将在降低NOx排放的同时，导致燃油经济性降低且需高压比的增压器匹配，使得配机成本增加，这些结论将为船用低速柴油机的进一步开发提供参考。

The Simulation Study on Performance Effect of Miller Cycle in Marine Low-speed Diesel Engine

For important meaning of Energy conservation and emission reduction on ship industry, model validation and simulation research of a type of Low-speed diesel engine applied Miller cycle technology have been done , and influence of Miller cycle strength on diesel engine performance has been analyzed, the effect of Miller cycle strength on diesel engine cylinder pressure, temperature, radiates rate and the NOx emissions have been given, integrated performance on ship with Low-speed diesel engine has been estimated. The research result shows that Miller cycle strength has larger impact to diesel engine cylinder inner temperature and the radiated rate, control Miller cycle strength can significantly reduce NOx emission, and exhaust valve closes 10oCA lately each, NOx generation volume reduces 6%-7%, when Miller cycle increases to a certain level, strengthening Miller cycle will lead fuel economy dropping and need to matching high pressure booster while NOx emission reducing, and making machine cost increased, These conclusions will provide reference for the further development of marine low-speed diesel engine.