TY - JOUR
T1 - Low-speed pre-ignition and super-knock in boosted spark-ignition engines : A review
AU - Rönn, Kristian
AU - Swarts, Andre
AU - Kalaskar, Vickey
AU - Alger, Terry
AU - Tripathi, Rupali
AU - Keskiväli, Juha
AU - Kaario, Ossi
AU - Santasalo-Aarnio, Annukka
AU - Reitz, Rolf
AU - Larmi, Martti
N1 - Funding Information:
The authors want to thank the support by the Dean’s grant of Aalto University School of Engineering , Henry Ford Foundation of Finland and Technology Industries of Finland, Combustion Engines Branch Group.
Publisher Copyright:
© 2022 The Authors
PY - 2023/3
Y1 - 2023/3
N2 - The introduction of downsized, turbocharged Gasoline Direct Injection (GDI) engines in the automotive market has led to a rapid increase in research on Low-speed Pre-ignition (LSPI) and super-knock as abnormal combustion phenomena within the last decade. The former is characterized as an early ignition of the fuel–air mixture, primarily initiated by an oil–fuel droplet or detached deposit. Meanwhile, super-knock is an occasional development from pre-ignition to high intensity knocking through detonation, which is either initiated by a shock wave interacting with a propagating reaction and cylinder surfaces or inside a hotspot with a suitable heat release and reactivity gradient. The phenomenon can be divided into four stages, including LSPI precursor initiation, establishment and propagation of a pre-ignited flame, autoignition of end-gases and development to a detonation. LSPI and super-knock are rare phenomena, difficult to observe optically in engines, and differences in methodologies and setups between steady-state experiments can lead to discrepancies in results. Experimental research has included more detailed approaches using glow plug-equipped engines, constant volume combustion chambers and rapid compression machines. In addition, the improved availability of mechanisms for fuel and lubricant surrogates has allowed researchers to model the oil–fuel interaction at the cylinder walls, evaporation and autoignition of oil–fuel droplets and regimes for different propagation modes of an autoignition reaction wave. This paper presents a comprehensive review of the underlying phenomena behind LSPI and its development to super-knock. Furthermore, it presents the methodology in experimental research and draws conclusions for mitigating strategies based on studies involving fuel, oil and engine parameters. Finally, it discusses the prerequisites for LSPI from oil–fuel droplets and the future needs of research as original equipment manufacturers (OEM) and lubricant industry have already adopted some proven solutions to their products.
AB - The introduction of downsized, turbocharged Gasoline Direct Injection (GDI) engines in the automotive market has led to a rapid increase in research on Low-speed Pre-ignition (LSPI) and super-knock as abnormal combustion phenomena within the last decade. The former is characterized as an early ignition of the fuel–air mixture, primarily initiated by an oil–fuel droplet or detached deposit. Meanwhile, super-knock is an occasional development from pre-ignition to high intensity knocking through detonation, which is either initiated by a shock wave interacting with a propagating reaction and cylinder surfaces or inside a hotspot with a suitable heat release and reactivity gradient. The phenomenon can be divided into four stages, including LSPI precursor initiation, establishment and propagation of a pre-ignited flame, autoignition of end-gases and development to a detonation. LSPI and super-knock are rare phenomena, difficult to observe optically in engines, and differences in methodologies and setups between steady-state experiments can lead to discrepancies in results. Experimental research has included more detailed approaches using glow plug-equipped engines, constant volume combustion chambers and rapid compression machines. In addition, the improved availability of mechanisms for fuel and lubricant surrogates has allowed researchers to model the oil–fuel interaction at the cylinder walls, evaporation and autoignition of oil–fuel droplets and regimes for different propagation modes of an autoignition reaction wave. This paper presents a comprehensive review of the underlying phenomena behind LSPI and its development to super-knock. Furthermore, it presents the methodology in experimental research and draws conclusions for mitigating strategies based on studies involving fuel, oil and engine parameters. Finally, it discusses the prerequisites for LSPI from oil–fuel droplets and the future needs of research as original equipment manufacturers (OEM) and lubricant industry have already adopted some proven solutions to their products.
KW - Autoignition
KW - Combustion
KW - Low-speed pre-ignition
KW - SI engine
KW - Super-knock
UR - http://www.scopus.com/inward/record.url?scp=85144430192&partnerID=8YFLogxK
U2 - 10.1016/j.pecs.2022.101064
DO - 10.1016/j.pecs.2022.101064
M3 - Review Article
AN - SCOPUS:85144430192
SN - 0360-1285
VL - 95
JO - Progress in Energy and Combustion Science
JF - Progress in Energy and Combustion Science
M1 - 101064
ER -