Towards In-Combustion-Event Feedback (ICEF) Control by Laser Ignition

该项目旨在探索基于激光点火（LI）的燃烧控制和传感科学，从而在未来的内燃机（IC）中实现燃烧事件反馈（ICEF）控制。其主要目标是为下一代发动机配置寻求LI和传感的优化，提供通过减少循环间变化来扩展分层GDI燃烧包线的知识，将燃油效率提高20%，并朝着大规模发动机NOX和HC排放减少的方向发展。这项工作将探索动态变化的时间和空间多点LI，燃烧特征的快速实时光学传感和多点ICEF的鲁棒反馈控制策略。人们普遍认为，在其他技术（如基于燃料电池的发电厂）发生重大取代之前，内燃机将在未来10-15年内继续成为主要的车辆发电厂。为了满足环境法规的要求，汽车制造商继续解决发动机性能的两个关键方面：燃油经济性和废气排放。新型发动机正变得越来越复杂，先进的燃烧机制燃烧越来越多的燃料，以满足未来的性能，燃油经济性和排放目标。在火花点火（SI）发动机中，火花塞自其发明以来基本上保持不变，并且由于其点燃高度稀释的空气燃料混合物的能力差而限制了提高效率的潜力。对于优化发动机性能也至关重要的是用于高速反馈控制的传感和诊断，但准确的实时缸内传感目前过于昂贵。LI提供了几种潜在的解决方案，包括点燃高度稀释的空气燃料混合物的能力。由于最近的激光技术的进步，燃烧控制参数的范围现在可以扩大到包括激光波长，脉冲持续时间，空间和时间的光能分布，单次和多次点火事件。现在有机会探索如何优化这些变量的动态选择，以便在最广泛的发动机运行条件下实现更高效、更清洁的燃烧。整体系统方法将包括利用自清洁光学路径用于LI和反馈传感目的，以允许探索信息丰富的燃烧监测和控制。需要一个广泛的计划来建立LI高度优化燃烧控制的基础工程科学，以适应特定的发动机配置、运行条件和燃料类型。关键的研究假设是，LI是一个可行的途径，燃烧的主动反馈控制，无论是循环的循环和最终在燃烧事件，通过多点/事件驱动和无延迟自清洁激光光学虚拟传感。除了实现完全ICEF控制的目标外，它还将为逐周期燃烧反馈控制提供更短期的开发潜力。将采用的研究方法包括以下方面的新工作：a/研究通过高速ICEF进行燃烧控制的LI机制，该机制源自激光波长调谐以及在多个焦点中空间和时间变化的能量传递，以适应燃料混合物的喷射模式、吸收和燃烧特性; B/同时使用自清洁光学路径，用于从LI实时捕获事件中的光特征; c/使用传感器数据和LI机制进行鲁棒优化的ICEF控制; d/使用SLM作为多点LI的手段; e/使用直接数值模拟（DNS）研究优化燃烧控制。利用该团队现有的发动机控制设施和与FMC的联系，将允许研究快速反馈控制及其相关的计算机控制问题，通过仪表化动力系统控制实验进行研究，并通过计算燃烧研究优化控制策略。

The project seeks to explore the science of laser ignition (LI) based control & sensing of combustion, leading towards In-Combustion-Event Feedback (ICEF) control in future internal combustion (IC) engines. The main objectives are to pursue optimisation of LI & sensing for next generation engine configurations, to provide knowledge to extend the stratified GDI combustion envelope by cycle-to-cycle variation reduction, to enhance fuel efficiency by up to 20% & progress towards large-scale engine NOX & HC emissions reduction. The work will explore dynamically varying temporal & spatial multi-point LI, rapid real-time optical sensing of combustion signatures and robust feedback control strategies for multi-point ICEF. It is widely accepted that the IC engine will continue to be the main vehicle power plant over the next 10-15 years, before significant displacement by other technologies (such as fuel cell based plant) takes place. To meet environmental legislation requirements, automotive manufactures continue to address two critical aspects of engine performance: fuel economy & exhaust gas emissions. New engines are becoming increasingly complex, with advanced combustion mechanisms that burn an increasing range of fuels to meet future goals on performance, fuel economy and emissions. In the spark-ignition (SI) engine, the spark plug has remained largely unchanged since its invention and limits the potential for improving efficiency due to its poor ability to ignite highly dilute air-fuel mixtures. Also vital to optimising engine performance is the sensing & diagnostics for high speed feedback control, but accurate real-time in-cylinder sensing is currently prohibitively expensive. LI offers several potential solutions, including the ability to ignite highly dilute air-fuel mixtures. Due to recent laser technology advances, the range of combustion control parameters can now be widened to include laser wavelength, pulse duration, spatial & temporal optical energy distribution, single & multiple ignition events. The opportunity now exists to explore how the dynamic selection of these variables can be optimised for more efficient and cleaner combustion over the widest range of engine operating conditions. The holistic systems approach will include making use of a self-cleaned optical pathway for both LI & feedback sensing purposes, to allow information-rich monitoring and control of combustion to be explored. An extensive programme is needed to establish basic engineering science for highly optimised combustion control by LI to suit specific engine configurations, operating conditions and fuel types. The key research hypothesis is that LI is a viable route to active feedback control of combustion, both cycle-by-cycle & ultimately within the combustion event, by multi-point / event actuation & delay-free self-cleaning laser optic virtual sensing. As well as progress towards the goal of full ICEF control, it will provide shorter term exploitation potential for in cycle-by-cycle combustion feedback control. The research methods to be adopted comprise novel work in: a/ the study of LI mechanisms for combustion control by high-speed ICEF, derived from laser wavelength tuning & spatially & temporally varied energy delivery in multiple foci to suit injection mode, absorption & combustion properties of fuel mixtures; b/ simultaneous use of a self-cleaned optical pathway for real-time in-event light signature capture from LI; c/ the use of sensor data & LI mechanisms for robust optimised ICEF control; d/the use of SLMs as a means to multipoint LI; e/ the optimisation of combustion control using Direct Numerical Simulation (DNS) studies. Use of the team's existing engine control facilities & liaison with FMC will allow study of rapid feedback control & its associated computer control issues, conducted through instrumented powertrain control experiments, with control strategies optimised via computational combustion research.