Abstract The potential of Humidified Enriched Air (HEA) on Diesel engine combustion is investigated, by means of 3D CFD combustion simulations, on a current production 4-cylinder turbocharged Diesel engine. HEA is supposed to be obtained by water degassing operation, exploiting the different vapor-liquid equilibria of it main constituents, nitrogen and oxygen. Simulations are carried out using a customized version of the KIVA 3V code, featuring a detailed chemistry combustion mechanism. The model of the engine is previously validated through comparison with experimental data and then it is used to analyse combustion and emissions of HEA combustion in combination with late injection strategies. Numerical results demonstrate that oxygen-enriched air enhances the thermal efficiency of the engine (up to 13%) and reduces significantly soot emissions; on the other hand, in-cylinder peak pressure and NOx emissions increase. The latter can be significantly reduced by using humidified air maintaining the advantage in terms of thermal efficiency and in soot reduction, nevertheless the baseline case NOx emissions cannot be restored.

中文翻译：

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加湿浓空气对柴油机燃烧和排放的影响

摘要 通过 3D CFD 燃烧模拟，在当前生产的 4 缸涡轮增压柴油发动机上研究了加湿富空气 (HEA) 对柴油发动机燃烧的潜力。HEA 应该通过水脱气操作获得，利用其主要成分氮和氧的不同汽液平衡。模拟是使用定制版本的 KIVA 3V 代码进行的，具有详细的化学燃烧机制。发动机模型通过与实验数据的对比验证，然后结合延迟喷射策略用于分析HEA燃烧的燃烧和排放。数值结果表明，富氧空气可提高发动机的热效率（高达 13%）并显着减少碳烟排放；另一方面，缸内峰值压力和氮氧化物排放增加。后者可以通过使用加湿空气显着减少，同时保持热效率和烟尘减少方面的优势，但无法恢复基线情况下的 NOx 排放。