Characterization of the low temperature chemistry of large hydrocarbons for model development in motor control

低温燃烧（NTV）可以提高发动机的效率，同时减少排放。在NTV中，产生尽可能均匀的燃料-空气混合物，并在自燃后燃烧。FOR 2401开发了NTV过程的控制方法，使发动机能够在广泛的特性领域中瞬时稳定地运行。NTV过程控制中的一个特殊挑战是由反应动力学和流体力学效应的卷积引起的跨尺度的周期性波动。因此，FOR 2401的概念是开发多尺度控制。NTV过程可以通过控制多次喷射、中间压缩、废气再循环和注水来控制。由于点火和污染物形成过程是由物质的动力学和在控制干预设定的条件下参与该过程的反应决定的，因此在部分燃烧的混合物与附加燃料的转化期间、在点火期间和在污染物形成期间，出现了关于反应序列的动力学问题。通过质谱法和气相色谱法分析流动反应器和充分搅拌反应器中燃料-空气混合物的转化率。通过改变压力、反应温度、停留时间和当量比，获得数据集，从这些数据集可以得出关于反应途径的结论。在实验上，实现了高达20巴的压力，特别是为了研究中间压缩或多次喷射的条件。本文系统地研究了正庚烷转化为正十二烷、异辛烷、甲苯和甲基环己烷的反应动力学。在FOR 2401中，这些数据将用于改进反应机理，预测发动机条件下的反应性，从而将动力学原理集成到控制策略中。此外，将研究燃烧期间离子形成与燃烧气体混合物的热力学状态之间的关系，以确定在发动机中相对容易测量的离子电流信号如何，可以与气缸压力结合使用作为控制参数。为此，首先检查离子形成相对众所周知的低压火焰。调查，然后扩展到NTV参数范围内的高压反应器，以找到在这些温度下的形成反应。理想地，即使在低温和中等压力下，离子形成也在尽可能少的形成反应中被捕获，然后可以以非常小的反应机制的形式被并入控制策略中。

Low-temperature combustion (NTV) can increase the efficiency of engines while reducing their emissions. In NTV a fuel-air mixture that is as homogeneous as possible is produced and burned after self-ignition. The FOR2401 develops approaches for the control of NTV processes that allow engines to be operated transiently and stably in a wide characteristic field. A particular challenge in the control of NTV processes are the cyclic fluctuations across scales caused by the convolution of reaction-kinetic and fluid mechanical effects. Consequently, the concept of the FOR2401 is to develop a multi-scale control. NTV processes can be controlled through controlled multiple injections, intermediate compression, exhaust gas recirculation and water injection. Since ignition and pollutant formation processes are determined by the kinetics of the substances and reactions involved in the process under the conditions set by the control interventions, kinetic questions arise concerning the reaction sequences during the conversion of partially combusted mixture with additional fuel, during ignition and during the formation of pollutants.To investigate these open questions, the conversion of fuel-air mixtures in a flow reactor and a well-stirred reactor is analyzed by mass spectrometry and gas chromatography. By varying the pressure, the reaction temperature, the residence time and the equivalence ratio, data sets are obtained from which conclusions on the reaction pathways can be drawn. Experimentally, pressures of up to 20 bar are realized, in particular to investigate the conditions of intermediate compressions or multiple injections. The work systematically addresses the reaction kinetics of the n-alkanes from n-heptane to n-dodecane, i-octane, toluene and methylcyclohexane, which are surrogate components of diesel or gasoline. Within the FOR2401, the data will be used to improve the reaction mechanism that predicts the reactivity under engine conditions and thus integrates the kinetic principles into the control strategies.In addition, the relationship between ion formation during combustion and the thermodynamic state of the combusted gas mixture will be investigated to determine how the ion current signal, which is comparatively easy to measure in the engine, can be used in combination with the cylinder pressure as a control parameter. For this purpose, low-pressure flames in which the formation of ions is relatively well known are examined first. The investigations are then extended to the NTV parameter range in the high-pressure reactor in order to find formation reactions at these temperatures. The ion formation is ideally captured in as few formation reactions as possible even at low temperatures and moderate pressures and can then be incorporated in to the control strategies in the form of very small reaction mechanisms.