Study on NH3 premixed combustion method by a fuel-rich prechamber gas jet using NH3 decomposition gas

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K04866
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 24020:Marine engineering-related
• Research Institution: National Institute of Maritime, Port and Aviation Technology
• Principal Investigator: Ichikawa Yasuhisa 国立研究開発法人海上・港湾・航空技術研究所, その他部局等, 研究員 (20586680)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 往復動内燃機関 / アンモニア / 副室 / 予混合燃焼

Outline of Final Research Achievements

The use of NH3 as a carbon-free fuel in reciprocating internal combustion engines is an attractive method in reducing greenhouse gases. NH3 is difficult to ignite and has a slow combustion speed. Therefore, the technological problems of NH3-fueled reciprocating internal combustion engines are combustion instability and unburnt NH3 emissions. We focus on NH3 premixed combustion method by a prechamber gas jet at fuel-rich condition using NH3 decomposition gas. In this study, an experimental system that can simulate the combustion phenomena in the prechamber and the main-chamber was made to investigate the basic combustion characteristics. The experimental results show that the higher the equivalence ratio in prechamber mixture, the flame was formed early.

Free Research Field

内燃機関

Academic Significance and Societal Importance of the Research Achievements

本研究では、NH3分解ガスを副室燃料として燃焼させ、主室に過濃燃焼ガス噴流トーチ火炎を形成することによって、主室内の燃焼困難なNH3／Air予混合気の、点火性を向上し安定燃焼を実現する燃焼手法に着目している。本研究において構築した副室・主室の燃焼を模擬できる実験システムを用いて、高速度カメラによる火炎の観察し燃焼基礎特性を調査した。実験の結果、火炎の形成時期は副室内当量比が高いほど早く有利であることなどが明らかになった。本成果は、実際のエンジンの検討・開発において有用な知見になると考える。