醇醚燃料发动机非常规污染物排放特性研究

在1台经过改装的单缸柴油机上,采用气相色谱和FT-IR红外光谱检测技术,开展了进气道喷射DME和甲醇双燃料HCCI燃烧方式,以及进气道喷射DME、缸内直喷甲醇双燃料复合燃烧方式下,非常规污染物排放特性的试验研究。结果表明,在不同的燃烧方式下均检测到甲醛、乙醛、甲酸、甲酸甲酯等非常规排放物,且甲醛是非常规排放物中的主要成分。DME—甲醇HCCI燃烧方式下,在同一负荷下随着甲醇喷射量的增加,甲醛、乙醛、甲酸甲酯的排放都有所增加;在同一甲醇浓度下随着发动机负荷的增加,甲醛的排放增加,乙醛的排放减少,甲酸甲酯的排放先减少后增加。复合式燃烧方式下,甲醛的排放随着有效功率的增大呈先降低后升高的趋势;甲酸甲酯和甲酸的排放均随着有效功率的增加而减少,随着DME喷射比例的增加而增加。DME—甲醇HCCI燃烧方式下,甲醇排放量增加十分明显。

Study on Unconventional Pollutant Emission Performance of DME-methanol Engine

On a modified single cylinder diesel engine,the dual fuel HCCI mode was developed by injecting DME and methanol in the inlet with the gas chromatography(GC) and Fourier transform infrared spectroscopy(FTIR) method.For the compound combustion of inlet DME and in-cylinder methanol,the unconventional pollutant emission performance was researched.The results show that,under different combustion modes,the pollutants of HCHO,CH3CHO,HCOOH and HCOOCH3 can be detected and HCHO is the main component of unconventional emission.In DME-methanol HCCI combustion mode,the HCHO,CH3CHO and HCOOCH3 emissions increase with the increase of methanol injection quantity at the same engine load.At the same methanol injection quantity,the HCHO emission increases,the CH3CHO emission reduces,and the HCOOCH3 emission first increases and then reduces with the increase of engine load.In the compound combustion mode,the HCHO emission first reduces and then increases,the HCOOCH3 and HCOOH emissions reduce with the increase of effective power and the latter increases with the increase of DME.The CH3OH emission increases obviously in DME-methanol HCCI combustion mode.