Detailed chemistry investigation for model development for engine control

该项目的作用是为研究股提供基本的化学知识。它致力于分析为发动机项目开发和关键检查反应动力学模型所需的物种分布，然后将这些模型纳入发动机控制例程。这些分析将主要在流动反应器中进行，在低温条件下使用替代燃料异辛烷(用于TP3的GCAI燃烧)和正庚烷(用于TP4的PCCI条件)。该项目侧重于相关反应动力学的几个方面。对于GCAI条件，一个重要的方面是水的添加对点火特性的影响。在不同条件下，我们将在一个参数场中研究可变加水对异辛烷反应动力学的影响，目的是了解加水对低温下反应动力学的基本机理，并将这一知识应用于模型的开发。计划中的调查正在处理这些条件下的新领域。因此，在预混平坦低压火焰的稳定条件下，该分析将得到选定研究的支持。对于PCCI领域的模型开发，计划详细调查在大约四个芳香环的区域内碳烟前体物种的形成，优先在低温条件下。虽然对第一个芳环的反应被认为是很好的理解，但在分子前体相到3-4个芳环的形成动力学的基本理解上仍然存在很大的差距。在从燃料分子到初始粒子的反应序列中，这一阶段延伸到第一次碳烟粒子成核，例如通过这种多环芳香化合物的二聚化，因此，关于这些过程的基础知识对TP4的模型开发具有重要影响。因此，这些调查将部分得到对非预混火焰中燃料非常丰富区域的分析的支持。此外，对于这两个发动机燃烧项目，了解排气成分对反应动力学机制的影响是很有意义的。在对加水的影响进行研究的基础上，计划进行针对这些影响的选定调查。作为所有装置中反应条件的函数的物种分布的确定将使用不同的质谱学技术，该小组在这方面有长期的经验。这些技术将得到用于温度测量的气相色谱和激光技术的支持。

The project serves to provide the fundamental chemical knowledge for the Research Unit. It is devoted to the analysis of species profiles that are needed for the development and critical examination of reaction kinetic models for the engine projects that will then be incorporated into the engine control routines. Theses analyses will be mainly conducted in a flow reactor under low-temperature conditions using the surrogate fuels iso-octane (for the GCAI combustion in TP3) and n-heptane (for the PCCI conditions in TP4). The project focuses on several aspects of the relevant reaction kinetics. For GCAI conditions, an important aspect is the influence of water addition on the ignition characteristics. The effects of variable water addition to iso-octane will be studied for a parameter field at different conditions with the aim to understand the fundamental mechanisms of water addition on the reaction kinetics in the low-temperature regime and to transfer this knowledge into the model development. The planned investigations are addressing new territory under these conditions. The analysis will thus be supported by selected studies under the stable conditions of premixed flat low-pressure flames. For the model development in the PCCI domain, detailed investigations of the formation of soot precursor species in the regime up to about four aromatic rings, preferentially under low-temperature conditions are planned. While reactions towards the first aromatic ring are thought to be well understood, large gaps remain in the fundamental understanding of the formation kinetics in the molecular precursor phase up to 3-4 aromatic rings. This phase that extends towards the first soot particle nucleation, for example via dimerization of such polycyclic aromatic compounds, is of eminent importance in the reaction sequences from the fuel molecule to the incipient particle, and consequentially, fundamental knowledge on these processes is of important influence for the model development for TP4. These investigations will thus be supported in part by analyses of very fuel-rich zones in a non-premixed flame. Furthermore, for both engine combustion projects, it is of interest to understand the influence of exhaust components on the reaction kinetic mechanisms. Building upon the study of the effects of water addition, selected investigations are planned which address these effects. The determination of species profiles as a function of reaction conditions in all set-ups will be performed using different variants of mass spectrometric techniques, for which the group has long-standing experience. These techniques will be supported by gas chromatography as well as laser techniques for the temperature measurements.