掺水燃烧对天然气发动机排放性的影响机理研究

Study on Influence Mechanism of Water Blended Combustion on Emissions of a Natural Gas Engine

掺水燃烧是稀薄燃烧天然气发动机用于减少排放污染物NOx的有效方法之一。基于水的热力特性及天然气燃烧特性对天然气掺水燃烧过程中污染物生成的机理进行了分析;并基于实验数据对进气管水喷射下稀薄燃烧天然气发动机主要排放污染物进行了测量。研究表明:掺水燃烧过程中,发动机缸内温度大幅下降,有效抑制了热力型NO的生成。水在参与燃烧过程中生成大量OH基有效抑制了快速型NO的生成。在转速1800rpm、水喷射量0.92g/s下,NOx下降70.4%。掺水燃烧过程产生的OH基同时有效促进了CO氧化生成CO_(2)。在转速1000rpm、水喷射量0.92g/s时,CO减少22.2%。

Water Blended Combustion is one of the effective methods for Lean-burn natural gas engines to reduce emissions of NOx.Based on the thermal characteristics of water and the combustion characteristics of natural gas,the mechanism of pollutant generation during the combustion process of natural gas mixed with water was analyzed;Based on the experimental data,the main emissions of Lean-burn natural gas engine with intake pipe Water Blended Combustion were measured.Research has shown that during the combustion process with water,the temperature inside the engine cylinder significantly decreases,effectively suppressing the generation of thermal type NO.During the combustion process,water generates a large number of OH groups,effectively suppressing the generation of rapid NO.At a speed of 1800rpm and a water injection rate of 0.92g/s,NOx decreased by 70.4%.The OH group generated during the combustion process of mixing water effectively promotes the oxidation of CO to generate CO_(2).At a speed of 1000rpm and a water injection rate of 0.92g/s,CO decreases by 22.2%.