Control of quasi-homogeneous combustion in diesel engines using fully-variable injection

该子项目的主要目标是使用基于优化控制的预混合充量压缩点火（PCCI）柴油燃烧过程的进一步发展。为此，整个喷射过程和整个燃烧功能分别被用作连续的致动和控制变量。为了能够建立一个周期到周期，理想情况下也是一个周期内的控制，这些变量必须被描述的物理基础上，低维参数化。在第一个供资期内，开发了基于无监督和有监督机器学习相结合的定量模型，并根据各种多次喷射模式的实验数据进行了验证，包括所谓的具有限制气缸压力上升率的阿尔法过程。利用TP 6的数据，开发了反应动力学模型，作为3D CFD模拟和模型简化的基础。为了在较宽的负荷范围内甚至在瞬态运行条件下应用各种性能参数的控制，将实施低温燃烧（LTC）和α过程的组合，并且将建立循环内控制方法。其基础是一个快速而精确的模型来描述非常早期的热释放对性能参数的影响。LTC和有限的气缸压力上升率之间的相互作用，以及其对性能参数的影响的分析将首先进行实验获得的数据空间。这形成了通过结合半物理的、基于反应动力学的建模方法来描述喷射/燃烧函数和燃烧函数/排放的关系的基础。对于实时燃烧控制的应用，这些将转化为一个低维的参数化。在这里，压力曲线分析的LTC的描述的独特性将严格审查和探索的离子电流测量的潜力作为一个补充参数，甚至取代压力曲线分析。基于反应动力学的非常早期的点火阶段的敏感性将被检查，这是非常重要的，在低温燃烧由于增加的时间比例的化学点火延迟。动力学模型，其中也包括离子流和污染物形成机制，将制定这个和其他分项目，并使用，例如，在降阶模型。CFD模拟将用于识别和解释相关性，并推导出相应的物理关系，以支持简化模型。将与TP 6合作开展LTC详细动力学、污染物排放和离子电流表征方面的工作。简化模型将与TP 7和单缸研究发动机合作进行验证。

The main goal of this subproject is the further development of the Premixed Charge Compression Ignition (PCCI) diesel combustion process using optimization-based control. For this, the entire injection process and the entire burn function are used as continuous actuation and control variables, respectively. In order to be able to establish a cycle-to-cycle, ideally also an in-cycle control, these variables must be described by physically-based, low-dimensional parameterizations. In the first funding period, quantitative models based on a combination of unsupervised and supervised machine learning were developed and validated from experimental data for various multiple-injection patterns including the so-called alpha-process with limiting cylinder pressure rise rate. With data from TP6, models for reaction kinetics were developed that serve as the basis for 3D CFD simulations and model reduction. In order to apply the control of various performance parameters over a wide load range and even for transient operation conditions, a combination of low-temperature combustion (LTC) and alpha-process will be implemented, and an in-cycle control approach will be established. The basis for this is a fast and precise model to describe the influence of the very early heat release on the performance parameters. The analysis of the interaction between LTC and limited cylinder pressure rise rates as well as its effect on the performance parameters will first be carried out using experimentally obtained data spaces. This forms the basis for the description of the relationships injection/burn function and burn function/emissions by incorporation of semi-physical, reaction-kinetics based modeling approaches. For the application in real-time combustion control, these will be transformed into a low-dimensional parameterization. Here, the uniqueness of the pressure curve analysis for the description of the LTC will be critically examined and the potential of ion current measurements explored as a complementary parameter or even to substitute the pressure curve analysis. The reaction-kinetics based sensitivities of the very early ignition phase will be examined, which are of great importance in low-temperature combustion due to the increasing temporal proportion of the chemical ignition delay. Kinetic models, which also include the ion current and pollutant formation mechanisms, will be developed for this and other sub-projects, and used, for instance, in the reduced order models. CFD simulations will be used to identify and explain correlations and corresponding physical relationships will be derived to support the simplified model. Work on the detailed kinetics of LTC, pollutant emissions, and ion current characterization will be carried out in collaboration with TP6. The simplified models will be validated in cooperation with TP7 and with the single-cylinder research engine.