柴油机排气过程对颗粒粒径及表面官能团的影响

Effect of Diesel Exhaust Process on Particle Size and Surface Functional Groups

通过运用发动机排气颗粒粒径谱仪(EEPS)采集了186F柴油机排气管不同位置的颗粒,分析了排气过程对颗粒粒径的影响。采用傅立叶红外光谱仪和X射线光电子能谱仪,对排气管不同位置采集的颗粒进行检测,研究排气过程对颗粒表面官能团的影响。研究结果表明,柴油机排气过程中,沿着气流运动方向,颗粒的平均粒径逐渐增大,核态颗粒的占比逐渐下降。排气过程中,颗粒表面化学组分基本一致,随着排气过程的进行,颗粒的表面脂肪族碳氢含量增加,颗粒中的C=O和C-OH含量上升,颗粒的氧化活性提高,有利于柴油机后处理装置DPF的再生。

The particulates in different positions of the exhaust pipe of the 186F diesel engine were collected by using the engine exhaust particle size(EEPS),and the effect of the exhaust transport process on the particle size is analyzed.The fourier infrared spectrometer and X ray photoelectron spectrometer were used to detect the particulates collected at different positions of the exhaust pipe,and the effect of the exhaust transport process on the surface functional groups of the particulates was studied.The results show that the average particle size of the particulates was increased gradually along the flow direction of the exhaust gas in the process of diesel exhaust transportation,and the proportion of the nuclear particulates was reduced gradually.In the process of exhaust transport,the chemical composition of the particulate surface was basically the same.With the process of exhaust transport,the aliphatic hydrocarbon content of the particulates was increased,the content of C=O and C-OH in the particulates was increased,and the oxidation activity of the particulates was increased.The study showed that,along the flow direction of diesel exhaust transportation,the oxidation activity of the particulates was increased which was beneficial to the regeneration of the diesel engine post treatment device DPF.