Due to worldwide increasingly sharpened emission regulations, the development of Gasoline Direct Injection and Diesel Direct Injection engines not only aims at the reduction of the emission of nitrogen oxides but also at the reduction of particulate emissions. Regarding present regulations, both tasks can be achieved solely with the help of exhaust after treatment systems. For the reduction of the emission of particulates, Gasoline (GPF) and diesel Particulate Filters (DPF) offer a solution and their implementation is intensely promoted. Under optimal conditions particulates retained on particulate filters are continuously oxidized with the exhaust residual oxygen so that the particulate filter (PF) is regenerated possibly without any additional intervention into the engine operating parameters. The regeneration behavior of PF depends on the reaction rates of soot particles with oxidative reactants at exhaust gas temperatures. The reaction rates of soot particles from internal combustion engines (ICE) often are discussed in terms of order/disorder on the particle nanoscale, the concentration and kind of functional groups on the particle surfaces, and the content of (mostly polycyclic aromatic) hydrocarbons in the soot. In this work the reactivity of different kinds of soot (soot from flames, soot from ICE, carbon black) under oxidation conditions representative for PF regeneration is investigated. Soot reactivity is determined in dynamic Temperature Programmed Oxidation (TPO) experiments and the soot primary particle morphology and nanostructure is investigated by High-Resolution Transmission Electron Microscopy (HRTEM). An image analysis method based on known methods from the literature and improving some infirmities is used to evaluate morphology and nanostructural characteristics. From this, primary particle size distributions, length and separation distance distributions as well as tortuosities of fringes within the primary particle structures are obtained. Further, UV–visible spectroscopy and Raman scattering and other diagnostic techniques are used to study the properties connected to the reactivity of soot and to corroborate the experimental findings. It is found that nanostructural characteristics predominantly affect reactivity. Oxidation rates are derived from TPO and interpreted on a molecular basis from quantum chemistry calculations revealing a replication/activation oxidation mechanism.

中文翻译：

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为什么烟灰与烟灰不同：低温烟灰氧化的分子/纳米结构方法

由于世界范围内日益严格的排放法规，汽油直喷和柴油直喷发动机的发展不仅旨在减少氮氧化物的排放，还旨在减少颗粒物的排放。根据目前的规定，这两项任务都可以仅借助排气后处理系统来实现。为了减少微粒的排放，汽油 (GPF) 和柴油微粒过滤器 (DPF) 提供了一种解决方案，并且它们的实施得到了大力推广。在最佳条件下，保留在微粒过滤器上的微粒会被尾气中的残留氧气持续氧化，因此微粒过滤器 (PF) 可能会再生，而无需对发动机运行参数进行任何额外干预。PF 的再生行为取决于烟灰颗粒在废气温度下与氧化反应物的反应速率。来自内燃机 (ICE) 的烟尘颗粒的反应速率通常从颗粒纳米级的有序/无序、颗粒表面官能团的浓度和种类以及（主要是多环芳烃）碳氢化合物的含量来讨论。烟灰。在这项工作中，研究了不同种类的烟灰（来自火焰的烟灰、来自 ICE 的烟灰、炭黑）在代表 PF 再生的氧化条件下的反应性。在动态程序升温氧化 (TPO) 实验中确定烟灰反应性，并通过高分辨率透射电子显微镜 (HRTEM) 研究烟灰初级粒子形态和纳米结构。使用基于文献中已知方法并改善一些弱点的图像分析方法来评估形态和纳米结构特征。由此，获得初级颗粒尺寸分布、长度和分离距离分布以及初级颗粒结构内的条纹曲折度。此外，紫外-可见光谱和拉曼散射以及其他诊断技术用于研究与烟尘反应性相关的特性并证实实验结果。发现纳米结构特征主要影响反应性。氧化率源自 TPO，并从量子化学计算的分子基础上进行解释，揭示了复制/激活氧化机制。