Chemical kinetics analysis on the low-speed pre-ignition

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K04214
• 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: Ibaraki University (2021); University of Fukui (2019-2020)
• Principal Investigator: Sakai Yasuyuki 茨城大学, 理工学研究科(工学野), 准教授 (70511088)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 低速プレイグニッション / 化学反応 / 潤滑油基油

Outline of Final Research Achievements

Based on the results of 0-dimensional combustion simulations using detailed chemical kinetics models, we have investigated the mechanism of low-speed pre-ignition (LSPI) which is one of abnormal combustion in spark-ignition engines. The amount of heat and radical concentration required to generate LSPI is quite large with considering the concentration of calcium sulfonate, an additive in lubricant. On the other hand, the paraffinic components of the base oil have higher reactivity compared to that of gasoline. Base oil can induce the ignition of gasoline under the temperatures and pressures encountered in spark-ignition engines. Therefore, from a chemical kinetics point of view, we concluded that the generation of LSPI is most likely derived from the combustion of the lubricant base oil.

Free Research Field

燃焼化学

Academic Significance and Societal Importance of the Research Achievements

ガソリンエンジンの熱効率向上を阻む異常燃焼の一つとして、近年採用されている高過給ダウンサイジングエンジンでは低速プレイグニッション（LSPI）の発生が問題視されている。本課題では、燃焼の化学素過程から、初めてLSPIの発生原因を解析して、基油の燃焼が原因と結論付けたところに意義がある。また、解析に利用したガソリン、添加剤熱分解成分、基油の模擬成分の反応モデルは、CAEを利用した高効率・クリーン燃焼技術の開発にも有効なツールとなる。