O_3/N_2氛围下微粒沉积特性对DPF再生的影响

Effects of Accumulation Characteristics of PM on DPF Regeneration Under O_3/N_2 Atmosphere

建立臭氧(O_3)与微粒(PM)的化学反应动力学模型,探究微粒层分布、微粒层最小厚度和微粒加载量对微粒捕集器(DPF)再生过程的影响,并对再生模型进行验证.结果表明:DPF内部微粒层的均匀分布可有效避免O_3穿透现象,提高O_3利用率,增大DPF再生速度,缩短DPF实现再生所用的时间;当微粒加载量一定时,微粒层最小厚度越大,微粒层分布越趋于均匀,DPF壁面峰值温度和再生速度越大,DPF实现完全再生时间越短.O_3/N_2氛围下,DPF离线再生的壁面峰值温度较低,可显著降低对DPF载体造成的热损坏;增加微粒加载量,可提高微粒的氧化速率和O_3利用率;可在不严重影响发动机工作性能的前提下,尽可能增加DPF的微粒加载量,提高再生经济性.

Effects of soot layer, minimum thickness of soot layer and initial mass of particulate matter （PM）on diesel particulate filter （DPF） regeneration were studied by the chemical reaction model of O3 and PM. Results indicate that avoiding O3 penetration, increasing the utilization rate of O3 and regeneration rate of DPF, shortening the time of DPF complete regeneration can be realized by the uniform soot layer in the DPF. When initial mass of PM keeps con- stantly, the soot layer becomes more uniform with the minimum thickness of soot layer increasing. Maximum temperature of wall and regeneration rate are increased, and the time for complete regeneration decreasing. Maximum temperature of wall is lower than those of other regeneration ways when DPF regeneration is working at O3/N2 atmosphere, reducing the thermal damage of DPF. Increasing initial mass of PM enhances the oxidation rate and utilization rate of O3. Initial PM mass of DPF is increased and enhance the economical efficiency of regeneration on condition of engine performance not seriously influenced.