ABSTRACT

Due to its high filtration efficiency, wall-flow diesel particulate filter (DPF) has become the mainstream purification device for particulate matters (PM) of diesel engine all over the world. China VI emission regulations further tightens PM emissions, which puts out higher demands on all aspects of DPF performance. In the paper, experimental and numerical study were conducted on a common-rail diesel engine for the pressure drop and temperature field characteristics of asymmetric cell technology (ACT) diesel particulate filter for silicon carbide (SiC-DPF) with high cell density and thin wall. The results show that the application advantage of ACT DPF is significant under the conditions of higher soot loading and higher engine speed while SCT DPF is more suitable for the conditions of lower soot loading (less than 4 g/L). When ash loading exceeds 30 g/L, the pressure drop of ACT DPF is remarkably lower than that of symmetric cell technology (SCT) DPF. Compared with SCT DPF, the gas flow velocity is faster at the channel outlet and the particulate concentration deposited along the axial direction is more homogeneous for ACT DPF. Therefore, pressure drop is reduced efficiently with the increasing soot loading. Moreover, the regeneration temperatures inside the ACT DPF are uniform and stable, and the peak temperature does not exceed 750°C during active regeneration with the soot loading of 8 g/L, thus regeneration is safe.

摘要

壁流式柴油微粒滤清器（DPF）由于过滤效率高，已成为世界各国柴油机颗粒物（PM）的主流净化装置。国六排放法规进一步收紧PM排放，对DPF各方面的性能提出了更高的要求。本文在共轨柴油机上对高密度薄壁碳化硅（SiC-DPF）非对称电池技术（ACT）柴油微粒过滤器的压降和温度场特性进行了实验和数值研究。 . 结果表明，ACT DPF在碳烟负载较高、发动机转速较高的条件下应用优势显着，而SCT DPF更适用于碳烟负载较低（小于4 g/L）的条件下。当灰分含量超过 30 g/L 时，ACT DPF 的压降明显低于对称电池技术 (SCT) DPF。与SCT DPF相比，ACT DPF在通道出口处气体流速更快，沿轴向沉积的颗粒浓度更均匀。因此，随着烟灰负载的增加，压降有效地降低。此外，ACT DPF内部的再生温度均匀稳定，在8 g/L的烟尘负载量下，主动再生时峰值温度不超过750℃，再生安全。ACT DPF在通道出口处气体流速更快，沿轴向沉积的颗粒浓度更均匀。因此，随着烟灰负载的增加，压降有效地降低。此外，ACT DPF内部的再生温度均匀稳定，在8 g/L的烟尘负载量下，主动再生时峰值温度不超过750℃，再生安全。ACT DPF在通道出口处气体流速更快，沿轴向沉积的颗粒浓度更均匀。因此，随着烟灰负载的增加，压降有效地降低。此外，ACT DPF内部的再生温度均匀稳定，在8 g/L的烟尘负载量下，主动再生时峰值温度不超过750℃，再生安全。