冷先银,何东泽,何志霞,等.点燃型预燃室在大缸径甲醇发动机上应用[J].内燃机工程,2021,42(5):60-69.
点燃型预燃室在大缸径甲醇发动机上应用
Application of Ignition Pre-Chamber in a Large-Bore Methanol Engine
DOI：10.13949/j.cnki.nrjgc.2021.05.009
关键词:甲醇发动机  点燃型预燃室  数值模拟  过量空气系数  点火正时
Key Words:methanol engine  ignition pre-chamber  numerical simulation  excess air ratio  ignition timing
基金项目:江苏省重点研发计划项目(BE2019009-5)，国家自然科学基金面上项目（51776088）
作者单位E-mail
冷先银* 江苏大学 能源研究院 xy.leng@foxmail.com 
何东泽 江苏大学 汽车与交通工程学院  
何志霞 江苏大学 能源研究院  
王谦 江苏大学 能源与动力工程学院  
隆武强 大连理工大学 能源与动力工程学院  
曹波 江苏泓润生物质能科技有限公司  
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摘要:通过计算流体动力学（computational fluid dynamics，CFD）数值模拟，探索点燃型预燃室在大缸径（320mm）甲醇发动机上的应用效果，计算了过量空气系数和点火正时对燃烧和性能的影响。结果表明，点燃型预燃室发动机的燃烧放热过程先缓后急，热效率较高，NOx排放很低，SOx排放为零，不经后处理即可满足国际海事组织（International Maritime Organization，IMO）Tier III排放法规。随着缸内过量空气系数的增加，缸内压力、压力升高率、爆震强度（ringing intensity，RI）和NOx排放均显著降低，指示热效率先升后降，在过量空气系数为2.4时达到最高值49.2%；随着点火正时的延迟，缸内压力、压力升高率、RI、指示热效率逐渐下降，NOx排放先减后增。基于计算结果，提出了一种燃烧控制策略：在平均有效压力(brake mean effective pressure，BMEP)低于1.8MPa时，控制缸内过量空气系数为2.4，并匹配较早的点火正时；在BMEP高于1.8MPa时，控制过量空气系数为2.1，匹配较晚的点火正时，从而使部分负荷热效率最佳，且整机具有较高的动力性。
Abstract:Through numerical simulations by methods of computational fluid dynamics (CFD), the effects of ignition pre-chamber on a large-bore (320mm) methanol engine were investigated, and the influences of excess air ratio and ignition timing on combustion and performance were simulated. Results show that, under the ignition pre-chamber mode, the combustion processes were characterized by initially slow and then rapid heat release rates, resulting in high thermal efficiencies, low NOx emissions and zero SOx emission, which can meet for the International Maritime Organization (IMO) Tier III emission regulations without aftertreatment. Furthermore, with the increase of the in-cylinder excess air ratio, the in-cylinder pressure, the pressure rise rate, the ringing intensity (RI) and the NOx emissions were significantly reduced, while the indicated thermal efficiency initially raised and then fell, reaching a peak value of 49.2% at the excess air ratio of 2.4；with the retarding of the ignition timing，the in-cylinder pressure, the pressure rise rate, the RI and the indicated thermal efficiency were reduced，while the NOx emissions initially fell and then raised. Based on the numerical results, a combustion control strategy was proposed: when the brake mean effective pressure (BMEP) is lower than 1.8MPa, the in-cylinder excess air ratio is controlled to 2.4, and using an earlier ignition timing; when the BMEP is higher than 1.8MPa, the in-cylinder excess air ratio is controlled to 2.1, and using a later ignition timing. With this strategy, the engine can obtain high power density while get optimum thermal efficiency at partial loads.
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