Development of Low-temperature Aftertreatment of Diesel Exhaust Participates Using plasma Actions

柴油发动机由于其低燃料成本和高能量效率而广泛用于运输和其他目的。然而，由于健康问题，来自废气的颗粒物（主要由各种形式的碳组成）的排放受到特别关注。因此，已经进行了许多对它们进行后处理的尝试，但是在满足充分后处理和低初始/操作成本的要求方面存在相当大的困难。这项工作已经进行，以寻求一种可能性，利用阻挡放电与致密化使用催化剂的组合。此外，SOF（可溶性有机部分）的后处理也将继续进行。主要的重点是利用具有大的表面积与体积比的蜂窝结构在低压损下实现这些功能。(1)本文提出了用过滤器捕集柴油机微粒并利用阻挡放电进行低温燃烧的方案。(2)研究了PZA（Pt-ZrO_2-Al_2O_3）对NOx的低温吸收和300℃以上的释放。还证明了使用PZA形成蜂窝结构。(3)在铜电极之间插入PZA蜂窝片，并用云母片隔开，成功地形成了阻挡放电。因此，可以利用放电循环来吸收和释放NOX。(4)利用静电捕集原理，成功地将微粒捕集到蜂窝结构阻挡放电元件之间的裸电极上，在此基础上，对柴油机排气微粒后处理元件进行了论证，并对整个元件进行了系统试验。

Diesel engines are widely used in transportation and other purposes, due to their low fuel cost and high energy efficiency. However, emission of particulates from exhausts, which mainly consist of various forms of carbon, has received particular attention because of health concern. Thus, there have been many attempts to aftertreatment them, but considerable difficulties exist to satisfy both requirements of sufficient aftertreatment and low initial/operating costs. This work has been undertaken to seek a possibility of exploiting the combination of barrier discharges with densifications using catalysts. Also, aftertreatments of SOF (Soluble Organic Fraction) are to be pursued. The main emphasis is to perform these functions at low pressure losses by utilizing a honeycomb structure, which has a large surface to volume ratio.The main results are summarized below.(1) The scheme of trapping of diesel particulates by a filter and their subsequent low temperature burning using barrier discharges has been demonstrated.(2) Absorption of NOX at low temperature and its release at above 300℃ using PZA (Pt-ZrO_2-Al_2O_3) were confirmed. The formation of honeycomb structure using the PZA was also demonstrated.(3) A barrier discharge was successfully formed between copper electrodes separated by mica sheet with PZA embedded honeycomb-shaped sheets inserted in the spaces. Thus, it has become possible to absorb and release NOX using discharge cycles.(4) Particulates were successfully collected toward bare electrodes between honeycomb-structured barrier discharge elements using the principle of electrostatic precipitation.Based on these results, the elements for the aftertreatment of diesel exhaust particulates have been demonstrated, and we intend to carry out the system test of the whole elements.