Expanding high ammonia energy ratios in an ammonia-diesel dual-fuel engine across wide-range rotational speeds

• Published in: Applied thermal engineering Vol. 251; p. 123608
• Main Authors: Mi, Shijie, Shi, Zhongrui, Wu, Haoqing, Zheng, Liang, Zhao, Wenbin, Qian, Yong, Lu, Xingcai
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 15.08.2024
• Subjects: Ammonia energy ratio; Carbon-free ammonia; Combustion; Emission; Principal component analysis; Wide-range engine speeds; Emission; Wide-range engine speeds; Combustion; Carbon-free ammonia; Ammonia energy ratio; Principal component analysis
• ISSN: 1359-4311
• DOI: 10.1016/j.applthermaleng.2024.123608

[Display omitted] •Wide-range rotational speed works at medium load.•The maximum ammonia substitution for diesel reaches 88%.•Indicated thermal efficiency is up to 47 % in 1800 rpm speed conditions.•Principal component analysis is used for dimensionality reduction and comparison. Ammonia (NH3), as a hydrogen carrier and carbon-free fuel, has garnered increasing attention for its potential to reduce carbon emissions in transportation. Due to the poor ignition characteristics of ammonia, the ammonia-diesel dual-fuel combustion mode is one of the pathways for achieving low carbon emissions in compression ignition engines. This study compared the combustion and emission characteristics of an ammonia-diesel dual-fuel engine at various speeds, ranging from 900 to 1800 rpm, with an extended ammonia energy ratio of 88 %. The results showed that advancing Start of Injection (SOI) moderately could reduce NH3 emissions. Higher engine speeds showed increased indicated thermal efficiency, reaching approximately 47 % at 1800 rpm. However, maintaining the ammonia energy ratio above 80 % at higher speeds became challenging. As the ammonia energy ratio increased, unburned ammonia emissions rose, while Nitrogen Oxides (NOx) emissions gradually decreased. Furthermore, a principal component analysis (PCA) was employed to integrate control parameters and combustion/emission characteristics of ammonia combustion, comparing correlations among different parameters. The results indicated that the control elements for unburned ammonia emissions primarily involve the diesel SOI and ammonia energy ratio.