PODE/甲醇二元燃料低温燃烧过程及污染物生成演化机制研究

传统点燃式内燃机热效率较低，而传统压燃式内燃机碳烟和氮氧化物（NOx）排放问题难以解决。聚甲氧基二甲醚（PODE）/甲醇二元燃料低温燃烧方式，采用进气道喷射甲醇形成均质混合气，缸内直喷PODE引燃，有望实现内燃机高效清洁燃烧。项目采用光学测量试验和化学反应动力模拟的方法，研究二元燃料的着火过程、放热规律和排放特性，探明二元燃料低温燃烧特征多样性及燃烧边界条件。运用敏感性分析法建立二元燃料化学反应动力学简化模型，探明燃料间化学反应的耦合作用，发展耦合化学反应动力学的三维燃烧模型，研究缸内着火过程、预混燃烧形式和分段燃烧放热规律，揭示燃料比例、喷射策略和废气再循环（EGR）对二元燃料低温燃烧过程的影响机制。采用光学诊断测量技术研究燃烧中间产物、自由基浓度分布和演化历程，揭示二元燃料低温燃烧污染物生成氧化机理。这一研究为拓展煤基燃料应用领域和控制污染物排放提供理论依据和技术支持。

The thermal efficiency of traditional spark ignition engine is relatively low, and the emission of soot and nitrogen oxide (NOx) from traditional compression ignition engine is difficult to solve. Polyoxymethylene dimethyl ethers (PODE) / methanol dual fuel low temperature combustion mode, using intake port injection methanol to form homogeneous mixture and direct injection PODE ignition, is expected to achieve high efficiency and clean combustion for internal combustion engines. The methods of optical measurement tests and chemical reaction dynamics simulation are used to study the ignition process, heat release regularity and emission characteristics of dual fuel. The combustion feature diversity and combustion boundary conditions of dual fuel low temperature combustion will be clarified. Based on sensitivity analysis method, dual fuel chemical reaction kinetics simplified mode will be constructed to ascertain the coupling effects of chemical reactions between two fuels. The dual fuel three-dimensional combustion mode coupled with chemical reaction dynamics will be developed to investigate the in-cylinder ignition process, premixed combustion patterns and staged heat release rate. Meantime, effect mechanism of fuel ratio, injection strategy and exhaust gas recirculation (EGR) on dual fuel low temperature combustion process will be clarified. Various optical diagnostic measurement techniques are used to study the concentration distribution and evolution process of the combustion intermediates and free radicals, so as to reveal the formation and oxidation mechanism of pollutants from dual fuel low temperature combustion. This study will provide the theoretical basis and technical support for expanding the application of coal-based fuels and controlling pollutant emissions.