合成燃料优化及提升发动机效率的实验与仿真研究

Experimental and Numerical Identification and Optimization of eFuel Potentials on Combustion Behavior and Engine Efficiency

摘要:

减少二氧化碳排放，放特别是减少汽油发动机的二氧化碳排放是目前正在急剧上升的一项要求。从能源的生命周期考虑，能源载体即化石燃料是产生二氧化碳排放问题的根本原因。采用从可再生能源中提炼出的合成燃料（eFuel），可使汽油发动机接近或达到二氧化碳排放的碳中和要求，因此配置eFuel的成分和性质至关重要，因为它将影响汽油发动机的工作过程和效率。eFuel的成分变化会显著影响汽油发动机的喷射、混合气形成、燃烧，以及后氧化和排气后处理等过程，因此，Dr. Ing. h.c. F. Porsche AG和FKFS合作开展了一系列相关研究，将不同的eFuel在单缸发动机试验台和喷雾试验台上进行了测试，并将其结果用于标定三维流体的仿真模型。同时，对eFuel的组成、混合气形成及燃烧特性进行深入分析，旨在提高汽油发动机效率，同时改善碳排放效果。除了进行单缸发动机测试外，还对汽油发动机配置进行虚拟优化，即通过替代燃料与发动机优化的相结合来提升汽油发动机的效率。

Abstract:

The demand for CO₂ reduction is rising sharply nowadays， especially for gasoline engines. Considering a life cycle analysis， the energy carrier， i.e. the fossil fuel is responsible for the emissions problem. The defossilization towards synthetic fuels from renewable energy sources （eFuels）， can make the combustion engine almost CO₂ neutral. The design of an eFuel composition and properties is crucial， as its formulation influences the gasoline engine processes and efficiency. From injection， mixture formation and combustion to post-oxidation and exhaust after treatment， a change in fuel composition has significant effects. For these reasons， several research projects were conducted as part of a collaboration between Dr. Ing. h.c. F. Porsche AG and FKFS. Measurements of a single-cylinder engine test bench and of a spray test ring with different fuels were produced and used to calibrate 3D-CFD simulation models.The fuel formulation， mixture formation and combustion behavior were analyzed deeply， with the aim of increasing engine efficiency while improving emissions. A virtual optimization of the engine configuration was possible in addition to single-cylinder engine tests， leading to significant potentials through alternative fuels and engine optimization.