A Study on the Practical Application of Marine Ultra-low Emission Engines through Piston Compression Reforming of Fuels

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K03890
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 19020:Thermal engineering-related
• Research Institution: Hokkaido University
• Principal Investigator: Shibata Gen 北海道大学, 工学研究院, 准教授 (70613785)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: 燃料改質 / ピストン圧縮 / ディーゼルエンジン / 合成ガス / バイオガス / 部分酸化反応 / 水性ガスシフト反応

Outline of Final Research Achievements

Reforming experiments were conducted to convert liquid fuel into syngas (hydrogen and carbon monoxide) through piston compression in a diesel engine, followed by chemical reaction analysis using chemical kinetics calculations. The reforming process of the fuel was influenced by the equivalence ratio and the peak temperature reached during reforming, with chemical reaction times being sufficiently rapid at normal engine speeds. The yield of syngas was found to be highest at oxygen concentrations of approximately 6% to 10% and equivalence ratios between 2 and 4.
Due to the issue of smoke emissions associated with liquid fuel, the experimental fuel was switched to methane, with a small amount of light oil injected into the cylinder for ignition. The diluent gas was changed from nitrogen to carbon dioxide to facilitate the dry reforming reaction. The results of the study revealed that syngas was produced through partial oxidation reactions and the reverse water-gas shift reaction.

Free Research Field

熱工学分野

Academic Significance and Societal Importance of the Research Achievements

エンジン車のさらなる高効率化が必要であり、市場の軽油やガソリンの着火性を変更できればエンジンはさらなる高性能化が期待できる。燃料の改質には触媒が用いられることが多いが耐久性が課題であり、ピストンの圧縮着火を利用した今回の研究は学術的に注目される。液体燃料の改質因子は圧縮時の温度と当量比であり、改質ガスの生成要因を突き止めることができた。また、後半はスモーク低減を目指して主燃料をメタンとし希釈ガスを二酸化炭素で実験をした。メタンや二酸化炭素でも水素や一酸化炭素の製造が可能であり、この結果は、エンジンを用いて温室効果ガスを削減し液体合成燃料の原料である合成ガスを製造できることを示唆している。