氨燃料内燃机研究现状及展望

Research Status and Future Prospects on Ammonia Fueled Internal Combustion Engines

为了满足碳中和目标,除了采用电驱系统和燃料电池发动机,还需要开发零碳或低碳燃料内燃机,以满足不同应用场景需求。氨作为零碳燃料和富氢载体,在碳中和时代越来越受到关注,成为研究热点。在总结氨及氨与其他燃料组成的混合燃料燃烧特性和燃烧机理基础上,分析氨在内燃机上应用的可行性,及与化石燃料内燃机相比氨内燃机显现的新特点,提出未来应用需要解决的关键技术。现有研究表明:氨燃料与其他高活性燃料组合,采用高活性燃料引燃是内燃机上比较可行的技术方案。内燃机可采用汽油、天然气、氢气引燃,与传统汽油机相比,在不改变发动机结构情况下,气态氨使内燃机动力性能降低,同时NOx和未燃NH3排放增加。压燃内燃机可采用低自燃温度燃料如柴油、二甲醚等引燃。与纯柴油或二甲醚内燃机相比,氨内燃机动力性能降低,排放与燃料混合比例相关。在所有引燃燃料中,采用氢燃料引燃燃烧改善效果最大,且为零碳排放,因而氨氢融合内燃机是碳中和时代非常有竞争力的零碳动力。未来,实现氨氢融合燃料内燃机应用也需要解决一些研发课题,包括专用氨喷射系统研发、合适的后处理系统研发和车载氨裂解系统研发等。

In order to meet the goal of carbon neutrality,diversified development is required.In addition to adopting electrification and fuel cell technology,it is also necessary to develop zero-carbon or low-carbon fuel Internal Combustion Engine(ICE)to meet the needs of different application scenarios.Ammonia,as a zero-carbon fuel and hydrogen carrier,has received increasing attention in the era of carbon neutrality.Many research institutions and universities have carried out research on ammonia as a fuel for ICE in the past 20 years.This review analyzes the feasible methods of ammonia application in ICEs based on a brief summary of the combustion characteristics and combustion mechanisms of ammonia and mixed fuels with other fuels,proposes new characteristics of ammonia ICEs compared to fossil fuel ICE and the key technologies that need to be addressed in future applications.The existing research shows that using high active fuels to ignite ammonia fuel is a feasible technical solution for ICEs.For Spark Ignition Internal Combustion Engine(SI-ICE),gasoline,natural gas and hydrogen can be used for ignition.Compared with traditional gasoline engines,gaseous ammonia reduces the power performance of the SI-ICE without changing the engine structure,while increasing the emissions of NOx and unburned NH3.For Compression Ignition Internal Combustion Engines(CI-ICE),low auto-ignition temperature fuels such as diesel and Dimethyl Ether(DME)can be used for ignition.Compared with pure diesel or DME ICE,the power performance of ammonia ICE decreases and emissions are related to the fuel mixture ratio.Among all ignition fuels,hydrogen fuel has the greatest potential for improving combustion and is zero-carbon emissions.Therefore,ammoniahydrogen fusion engines are very competitive zero-carbon power in the era of carbon neutrality.Finally,there are some problems that need to be solved for the future application of ammonia-hydrogen mixed fuel,including the development of dedicated ammonia injection systems,suitable post-treatment systems and on-board ammonia cracking systems.