喷油参数对PODE/柴油混合燃料燃烧污染物排放的影响

以柴油(P0)、聚甲氧基二甲醚(PODE)/柴油混合燃料(P10和P20)为对象，在高压共轨柴油机上，考察其在不同喷油压力和喷油正时下的燃烧排放特性及颗粒物排放规律。结果表明：随混合燃料中PODE体积分数的增加，燃料燃烧缸内压力和放热率峰值有所降低；随着喷油压力的提高，3种燃料的CO、碳氢化合物(HC)和烟度排放均明显下降，NO_x排放有所上升，排气颗粒的峰值数量浓度不断降低，其中积聚态颗粒占比降低，核态颗粒占比增加；推迟喷油可以降低NO_x排放，但会增加CO、HC和烟度排放，颗粒的数量浓度有所增加；3种燃料中，P10燃料NO_x生成量和排气颗粒的几何平均直径受喷油压力和喷油正时影响最小。

Effects of Injection Parameters on the Combustion Pollutants Emissions of PODE/Diesel Blended Fuels

The combustion emission characteristics and particulate emission of diesel(P0), polyoxymethylene dimethyl ethers (PODE)/diesel (P10 and P20) were investigated at different injection pressures and injection timings with a high pressure common-rail diesel engine. Results show that the peak values of combustion pressure and heat release rate decrease by the increase of PODE volume fraction. With the increase of injection pressure, CO, Hydrocarbons(HC)and soot emissions of the three fuels decrease obviously while NO_x emission increases. The peak values of exhaust particles number concentration decrease, among which the proportion of accumulation particles decrease while the proportion of nucleation particles increases. With the delay of injection timing, the NO_x  emission decreases, while the CO, HC， soot emissions and particle number concentration increase. Compared with P0 and P20 fuels, the NO_x emission and the particle geometric mean diameter (GMD) of P10 are less affected by the injection pressure and injection timing.