【摘要】 为了使天然气发动机在采用机内净化措施的情况下大幅度降低NOx排放,满足未来的排放法规,试验研究了3种稀释方式(空气稀释、当量燃烧+EGR稀释、空气与EGR双重稀释)对稀燃天然气发动机控制NOx排放潜力的影响,并考察了燃烧边界条件的改变对发动机燃烧及排放性能的影响。研究结果表明:通过燃烧边界条件优化,3种稀释方式均能使发动机NOx排放满足国-Ⅳ及国-Ⅴ排放标准,在同等NOx排放前提下,对其经济性而言,双重稀释方式优于空气稀释方式,空气稀释方式优于当量燃烧+EGR稀释方式。更多还原

【Abstract】 In order to research potential of various dilution methods to remove NOx emissions of lean-burn compressed natural gas(CNG) engine by engine internal purification,three kinds of dilution methods,air dilution,stoichiometric combustion with EGR dilution and dual dilution(combined air dilution and EGR dilution) were investigated experimentally.The influences of combustion boundary condition change on engine combustion and emissions were also studied.Results show that engine NOx emissions can meet China phase Ⅳ and Ⅴ standards by using the three kinds of dilution methods if combustion boundary conditions are optimized.From the view point of fuel economy,the superiority order of three methods is dual dilution,air dilution,stoichiometric combustion with EGR dilution,in condition of maintaining the same NOx emission level.更多还原