二甲醚(DME)发动机排放性研究

Study on the Emission Performance of DME Engines

本文根据二甲醚(DME)的物理化学特性对其碳烟及NOx排放性进行分析,叙述了DME的NOx排放控制策略。分析结果表明:DME没有C-C键且燃料中氧含量较高,使DME发动机可以实现无烟燃烧;由于DME滞燃期短、汽化潜热大且理论空燃比低,使DME发动机的NOx排放较低;降低DME发动机NOx排放最有效的方法包括排气再循环(EGR)技术和电控喷射。目前冷EGR技术可靠性、实用性较好。

The soot and NOx emissions of a DME engine are analyzed according to the physicochemical characteristics of the DME fuel.The NOx emission control strategy of the DME engine is introduced.Results show that smokeless combustion can be realized with DME fuel due to high oxygen contents and there are no C-C bonds in DME.On the other hand,there is a low NOx;emission because of a shorter ignition delay period,a larger latent heat of vaporization and a lower ideal air-fuel ratio.The most effective methods to reduce NOx;emission include electronic controlled injection technique and EGR technique.And the EGR technique is a more reliable and practical technique at present.