PODE/甲醇双燃料发动机甲醛排放生成特性研究

Study on Formaldehyde Emission Generation Characteristics of PODE/Methanol Dual-fuel Engines

通过CONVERGE软件耦合聚甲氧基二甲醚(PODE)/甲醇化学反应动力学机理建立了双燃料燃烧数值模型,仿真研究了甲醇比例对双燃料燃烧模式下缸内温度场和甲醛浓度场的分布特性。同时,在一台四缸高压共轨发动机上实现了PODE/甲醇双燃料燃烧模式,试验研究了甲醇比例、喷油正时和进气温度对双燃料燃烧甲醛排放特性的影响。结果表明,随着甲醇比例的增加,双燃料燃烧的缸内温度场分布更加均匀,甲醛排放增加。随着喷油正时提前、负荷增加和进气温度提高,甲醛排放均呈降低趋势。

A numerical model of dual-fuel combustion was established by coupling the kinetic mechanism of polymethoxydimethyl ether(PODE)/methanol chemical reaction by converge software, and the distribution characteristics of methanol ratio on cylinder temperature field and formaldehyde concentration field under dual-fuel combustion mode were simulated and studied. At the same time, the dual-fuel combustion mode of PODE/methanol was realized on a four-cylinder high-pressure common rail engine, and the effects of methanol ratio, fuel injection timing and intake air temperature on the formaldehyde emission characteristics of dual-fuel combustion were experimentally studied. The results show that with the increase of methanol proportion, the temperature field distribution in the cylinder of dual-fuel combustion is more uniform, and the formaldehyde emission increases. With the advance timing of fuel injection, the increase of load and the increase of intake air temperature, formaldehyde emissions have a decreasing trend.