Investigation into engine performance of a hydrogen-dimethyl ether spark-ignition engine under various dimethyl ether fractions

• Published in: Fuel (Guildford) Vol. 306; p. 121429
• Main Authors: Cong, Xiaoyu, Ji, Changwei, Wang, Shuofeng
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 15.12.2021; Elsevier BV
• Subjects: Blending; Carbon monoxide; Combustion; Compression; Dimethyl ether; Emissions; Flame propagation; Fractions; High temperature; Hydrocarbons; Hydrogen; Hydrogen engines; Hydrogen fuels; Nitrogen oxides; Oxidation; Photochemicals; Propagation; Reduction; Spark ignition; Spark ignition; Combustion; Dimethyl ether; Hydrogen; Emissions
• ISSN: 0016-2361; 1873-7153
• DOI: 10.1016/j.fuel.2021.121429

•SI engines fuelled with hydrogen and dimethyl ether could achieve carbon neutrality.•Performance of a hydrogen-dimethyl ether SI engine under various αDME was studied.•Low-temperature oxidation was found in HRR curve, but the peak values were lower than 1 J/°CA.•After dimethyl ether addition, Imep was improved and NOx emissions were reduced up to 49.9%. Spark-ignition combustion mode could be used to widen the operation range of homogeneous charge compression ignition combustion mode on a hydrogen-dimethyl ether (DME) engine. To improve power output and reduce nitrogen oxides emissions, this study investigated the combustion and emissions properties of a hydrogen-DME spark-ignition engine under various DME fractions (αDME). The result showed that flame development and propagation periods were extended after DME blended. The increases of both periods were 1.7 and 2.0 °CA when αDME various from 1.4% to 3.0%, respectively. However, when αDME increased to 3.4%, flame propagation period had a 1.7 °CA reduction because of the spontaneous high-temperature oxidation of a few end unburned mixtures. Blending DME could improve power output of the neat hydrogen engine. The maximum improvement of indicated mean effective pressure could achieve 18.3%, after DME addition. Because of the weakened flame kernel and flame propagation process, when αDME lower than 3.0%, blending DME increased cyclic variation yet the variations were in 0.13%. Nitrogen oxides emissions could be reduced significantly, when DME was added into the neat hydrogen engine. The maximum reduction could achieve 49.9%, based on neat hydrogen fuel-supply mode. Hydrocarbon and carbon monoxide emissions were increased after DME addition. When αDME increased from 1.4% to 3.4%, the enhancement of hydrocarbon emissions was about two-third lower than that of carbon monoxide emission.