掺烧不同比例二甲醚柴油机燃烧与排放特性的影响

为研究不同比例的二甲醚/柴油混合燃料的燃烧性能与排放特性的研究，以4190ZLC-2型船用中速柴油机为原型机，运用AVL_FIRE仿真软件构建燃烧室高压循环模型，首先通过仿真数据与台架试验的缸压曲线进行对比，验证模型的准确性。研究结果表明：经过双喷油孔的二甲醚（DME）进入缸内后，呈现明显的燃烧阶段DME低温燃烧和柴油扩散燃烧；随着DME的掺烧比例的增大，缸内压力和温度峰值有增大的趋势，对应的相位有所提前；在100%负荷工况下NOX排放最终呈现先减小后增大；在CO和碳烟排放中呈现显著降低趋势。在反应过程中掺烧DME缩短了滞燃期和燃烧持续时期，混合质量较柴油好，DME和柴油混合后有良好的雾化特性，为后期的DME研究提供参考。

Effects of different DME ratios on combustion and emission characteristics of diesel engines

?In order to study the combustion performance and emission characteristics of different proportions of DME/ diesel fuel mixture, the 4190zlc-2 marine medium-speed diesel engine was taken as the prototype, and the AVL_FIRE simulation software was used to build the high pressure circulation model of combustion chamber. Firstly, the cylinder pressure curve was compared with simulation data and bench test to verify the accuracy of the model. The results show that: after the DME enters the cylinder through the double injection holes, it presents obvious combustion stage: DME low-temperature combustion and diesel diffusion combustion. With the increase of DME mixing ratio, the peak pressure and temperature in the cylinder tend to increase, and the corresponding phase is somewhat advanced. Under 100% load condition, NOx emission finally decreases first and then increases. CO and carbon smoke emissions showed a significant decrease trend. The mixing of DME in the reaction process shorteneth the delay period and combustion duration, and the mixing quality is better than that of diesel. After the mixing of DME and diesel, it has good lubrication and atomization characteristics, providing a reference for the later research of DME.