Fundamental Study on Dual-fuel Engine Combustion Based on Fuel Design Concept

柴油机广泛用作商用车、工程机械和农业机械的动力装置。然而，最近的社会趋势，以及有关柴油引擎的严格排放法例，都可能促使当局在不久的将来采取立法行动，以较清洁的燃料部分取代柴油。中国和德国都是汽车产销大国，都加入了应对全球气候变化的《巴黎协定》。因此，两国在交通领域的节能减排需求是一致的，发展高效、清洁的柴油发动机燃烧概念，如双燃料压燃式发动机，符合两国的国家战略。所谓双燃料发动机的燃烧过程是指直接喷射的燃料在预混气体或液体燃料/空气环境中的压缩点火过程。其根本原因是，在双燃料燃烧中，大部分直接喷射的燃料是在预混燃烧状态下燃烧的，扩散燃烧产生的碳烟可以显著减少。此外，根据预混燃料和直喷燃料的碳含量，双燃料运行模式可以显著减少二氧化碳排放。该项目中拟议的联合研究将利用上海交通大学(SJTU)和弗里德里希-亚历山大-纽伦堡大学(FAU)的互补设施和专业知识，开发和优化使用天然气、甲醇、二甲醚和聚甲醛二甲醚等低碳燃料的双燃料发动机。基于要解决的科学问题和要使用的技术，FAU将重点描述双燃料制度下的燃料喷射、混合和点火过程，使用能够提供超高温和高压环境的内部设计的恒容容器。这些发现将为双燃料发动机可控点火和高效低排放燃烧策略的开发提供科学和技术指导，该策略将由上海交通大学团队进行。此外，上海交通大学和上海交通大学的合作将为双方的博士生和早期职业研究人员提供一个独特的培训平台。这一独特的培训经历将使他们具备技能、知识和国际视野，为他们未来的职业生涯做出贡献，并使他们能够为未来的全球问题提出可能的解决方案。

Diesel engines are widely used as power devices in commercial vehicles, engineering and agricultural machineries. However, recent social trends as well as the stringent emissions legislations referring to diesel engines are able to precipitate legislative actions for the partial substitution of diesel by cleaner fuels in the imminent future. China and Germany are both the primary countries of automobile production and sales, and have both joined the Paris Agreement to cope with the global climate change. Therefore, both countries have the same demand in energy saving and emissions reduction in the transportation field, and the development of high efficiency and clean diesel engine combustion concepts, e.g. dual-fuel compression ignition engines, is in line with their national strategies. The combustion process in the so called dual-fuel engines refers to the compression ignition of the directly injected fuel in a premixed gaseous or liquid fuel/air environment. The underlying cause is that in a dual-fuel combustion, most of the directly injected fuel is burned in the premixed combustion regime and soot formation from the diffusive burn could be significantly reduced. Furthermore, depending on the carbon content of the premixed and directly injected fuel, the dual-fuel operation mode can lead to significant decrease in carbon dioxide emission. The proposed joint research in this project will exploit the complementary facilities and expertise of Shanghai Jiao Tong University (SJTU) and Friedrich-Alexander-University of Erlangen-Nuremberg (FAU) for the development and optimization of dual-fuel engines with low-carbon fuels such as natural gas, methanol, dimethyl ether and polyoxymethylene dimethyl ethers. Based on the scientific problems to be addressed and techniques to be used, FAU will focus on the characterization of the fuel injection, mixing and ignition processes in the dual-fuel regime using an in-house designed constant volume vessels which is able to provide an ultra-high temperature and pressure environment. The findings will provide scientific and technical guidance for the development of controllable ignition and highly efficient, low emissions combustion strategies for dual-fuel engines, which will be conducted by the SJTU team. Additionally, the collaboration between SJTU and FAU will offer a unique training platform for PhD students and early career researchers from both sides. This unique training experience will equip them with skills, knowledge and international vision, contributing to their future careers and also enabling them to propose possible solutions to global problems in the future.