Combustion Characteristics of Ammonia in a Modern Spark-Ignition Engine
Combustion Characteristics of Ammonia in a Modern Spark-Ignition Engine
复制标题
现代火花点火发动机中氨的燃烧特性
DOI：
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发表时间：
2019
期刊：
影响因子：
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通讯作者：
C. Rousselle
中科院分区：
文献类型：
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作者：
C. Lhuillier;P. Brequigny;F. Contino;C. Rousselle
由于其无碳特性、具有竞争力的能量密度以及非常成熟的生产、储存和运输过程，氨现在被认为是氢能经济背景下的一项非常重要的资产。如果由可再生能源生产，它作为直接燃烧燃料的使用可以参与电力部门的灵活性，并有助于减少某些部门的化石燃料使用，如长途航运。然而，氨的燃烧性能不佳，需要在实际系统中进一步研究其燃烧特性。在本研究中，用不同当量比和进气压力的气态氨/空气混合物作为现代单缸火花点火发动机的燃料。结果与甲烷/空气和以前的氨/氢/空气测量结果进行了比较，其中氢被用作燃烧促进剂。测量和分析了选定物种的缸内压力和排气浓度。结果表明，氨是一种非常适合用于SI发动机运行的燃料，因为通过利用富氢或增加进气压力的促进作用，或两者的结合，可以获得令人满意的高功率输出。nh3加注下的性能与甲烷加注下的性能比较好。在低燃料和富燃料条件下，还分别观察到较高的氮氧化物和未燃烧的nh3废气浓度，要求采取额外的缓解措施。详细的燃烧分析表明，氢主要起助燃剂的作用。在发动机中，纯氨燃烧被认为主要是由氨的点火动力学和湍流火焰响应驱动，而不是由层流燃烧速度驱动。
Ammonia is now recognized as a very serious asset in the context of the hydrogen energy economy, thanks to its non-carbon nature, competitive energy density and very mature production, storage and transport processes. If produced from renewable sources, its use as a direct combustion fuel could participate to the flexibility in the power sector as well as help mitigating fossil fuel use in certain sectors, such as long-haul shipping. However, ammonia presents unfavorable combustion properties, requiring further investigation of its combustion characteristics in practical systems. In the present study, a modern single-cylinder spark-ignition engine is fueled with gaseous ammonia/air mixtures at various equivalence ratios and intake pressures. The results are compared with methane/air and previous ammonia/hydrogen/air measurements, where hydrogen is used as combustion promoter. In-cylinder pressure and exhaust concentrations of selected species are measured and analyzed. Results show that ammonia is a very suitable fuel for SI engine operation, since high power outputs were achieved with satisfying efficiency by taking advantage of the promoting effects of either hydrogen enrichment or increased intake pressure, or a combination of both. The performances under NH 3 fueling compare well with those obtained under methane operation. High NOx and unburned NH 3 exhaust concentrations were also observed under fuel-lean and fuel-rich conditions, respectively, calling for additional mitigation measures. A detailed combustion analysis show that hydrogen mainly acts as an ignition promoter. In the engine, pure ammonia combustion is assumedly mainly driven by the ignition kinetics of ammonia and the flame response to turbulence rather than by the laminar burning velocity.