喷油正时对双燃料船用中速柴油机燃烧性能影响研究

Effect of injection timing on combustion performance of marine medium speed engines

为了研究喷油正时对船用中速发动机燃烧性能的影响,本文以MAN L23/30H中速柴油机为研究对象,通过数值模拟技术搭建柴油、双燃料发动机的计算模型,以原始发动机实验数据为参照,进行模型的校准与完善。通过改变天然气替代率(0%,25%,50%,75%)以及喷油正时(SOI=-10°CA,-5°CA,0,5°CA),进行船用中速柴油机的燃烧性能研究。研究结果表明:在纯柴油模式下,随着喷油正时的推迟,发动机单缸指示功率及平均有效指示压力下降,NO排放降低;在双燃料模式下,发动机的动力性对喷油正时更为敏感,由喷油延迟造成的动力性削减较纯柴油模式大。

In order to study the effect of fuel injection timing on the combustion performance of marine medium speed engine,in this paper,MAN L23/30H medium-speed engine is taken as the research engine,and the calculation model of diesel engine and dual-fuel engine is built through numerical simulation technology.With the original engine test data as reference,the model is calibrated and improved.The combustion performance of marine medium-speed engines is studied by changing the substitution rate of natural gas(0%,25%,50%,75%)and injection timing(SOI=710,715,720,725°CA).The result of research shows that In the diesel mode,with the delay of fuel injection timing,the indicated power and average effective indicated pressure of the single cylinder of the engine decreased,and NO emission decreased,In the dual-fuel mode,the dynamic performance of the engine is more sensitive to the injection timing and the reduction of dynamic performance caused by the injection delay is larger than that in the pure diesel mode.