Article
Energy & Fuels
Osama Hmood, Edgar Matida
Summary: The study introduces a method to estimate ignition delay based on temperature measurements and finds that the fuel-air mixture becomes pseudo-homogeneous during long periods of ignition delay, with the charge pressure having a significant effect on the delay.
Article
Energy & Fuels
Joel Mortimer, Farzad Poursadegh, Michael Brear, Stephen Yoannidis, Joshua Lacey, Yi Yang
Summary: This paper presents an experimental and numerical study of a boost-enabled, spark ignited, heavy-duty, hydrogen-fuelled engine with direct injection. The research finds that engine operation at higher compression ratios without water injection leads to knock-limited conditions and requires richer fuel mixtures and advanced spark timing. Water injection suppresses autoignition and knock, allowing for richer operation and improving engine performance. Numerical analysis shows that the dominant impact of water injection is charge cooling, while the thermophysical effect is significant and the kinetic effect is weak.
Article
Engineering, Electrical & Electronic
Haiwen Ge, Ahmad Hadi Bakir, Peng Zhao
Summary: Hydrogen and ammonia are carbon-free fuels with massive production potential. Adding ammonia to hydrogen can effectively modulate flame speed and mitigate engine knock, while retaining the zero-carbon nature of the system. The parametric study shows the great potential of hydrogen/ammonia blends in high-speed spark-ignition engines.
Article
Chemistry, Multidisciplinary
Aqian Li, Zhaolei Zheng, Yukun Song
Summary: This study investigates the feasibility of water injection technology in reducing knock tendency of GDI engines through numerical simulation methods. It is found that using LPNA water injector arrangement can effectively reduce knock intensity. Additionally, the results show that when the water injection pressure is 5 bar, the engine experiences minimum knock intensity, highest cycle work, and lowest emissions.
Article
Thermodynamics
Shang Liu, Zhelong Lin, Hao Zhang, Nuo Lei, Yunliang Qi, Zhi Wang
Summary: Increasing the compression ratio of gasoline engines can improve fuel efficiency, but engine knock caused by auto-ignition is still a challenge for high compression ratio hybrid engines. This study investigates the effects of blending ammonia on knock suppression, combustion characteristics, thermal efficiency, and emission performance in a high compression ratio gasoline engine.
Article
Energy & Fuels
Ahmad Almaleki, Paul Hellier, Nicos Ladommatos, Midhat Talibi, Zuhaib Khan
Summary: This study investigates the influence of varying relative air-fuel ratios (exhaust lambda) on the knock resistance of a range of fuels with different RON values and chemical compositions. It was found that fuels with equivalent RON values have the same compression ratio at fuel rich conditions, but exhibit significant differences at stoichiometric conditions (lambda = 1). The knock resistance of paraffinic reference fuels is more sensitive to changes in exhaust lambda, especially at lambda = 1, requiring higher engine compression ratios compared to aromatic gasoline fuels to achieve equivalent knock levels.
Article
Engineering, Aerospace
D. O. Glushkov, K. K. Paushkina, A. O. Pleshko, V. A. Yanovsky
Summary: A study was conducted on oil-filled cryogels with fine particles (Al, Cu, Fe, carbonaceous, inert) and without them to prepare elastically deformable gel fuel compositions. When exposed to radiant heating at an oxidizer temperature of 600-1000 degrees C, the fuel particles consistently ignited with dispersion that had a positive effect on the intensity of the fuel component burnout. Different fuel compositions exhibited varying ignition delay times, velocities, and average diameters of the burnout area. The gel fuel composition with fine carbonaceous particles ignited most rapidly, while the composition with Al particles had the highest ignition delay times and lowest velocities of fine fragments.
Article
Engineering, Mechanical
James C. Peyton Jones, Saeed Shayestehmanesh
Summary: This study conducted a statistical analysis of raw knock cylinder pressure and accelerometer signal time histories, revealing the nonstationary stochastic characteristics of these signals as they evolve with crank angle and spark timing changes. The data approximation as a cyclically independent process and the fitting of a dual-Gaussian model provide empirical insight into the knock phenomenon. The research highlights the importance of understanding knock behavior for modern engine design and the need for closed-loop knock controllers to optimize engine performance.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2021)
Article
Energy & Fuels
Qi Jing, Dan Wang, Congling Shi
Summary: In this study, the deflagration and detonation properties of multiphase mixed fuels obtained by adding different morphologies and particle sizes of aluminum powder to the JP-10/DEE mixed fuel were investigated. Under weak ignition conditions, adding aluminum powder significantly increases the average burning rate and flame intensity of the multiphase mixed fuel. However, the addition of aluminum powder also leads to incomplete combustion and the generation of a large amount of soot in the oxygen-depleted state. Under strong ignition conditions, the DDT process of JP-10/DEE/aluminum powder can be divided into four stages, corresponding to four different pressure wave patterns.
Article
Energy & Fuels
Antonio Viayna, Ouldouz Ghashghaei, David Vilchez, Carolina Estarellas, Manuel Lopez, Jesus Gomez-Catalan, Rodolfo Lavilla, Jesus Delgado, F. Javier Luque
Summary: The study proposes a strategy to increase fuel octane number by tailoring fuel properties with additives, using high-throughput screening to identify promising compounds as anti-knock additives, and conducting environmental and toxicological risk assessments.
Article
Energy & Fuels
Wei Liu, Yunliang Qi, Ridong Zhang, Qihang Zhang, Zhi Wang
Summary: Jet ignition (JI) is a promising way to increase engine thermal efficiency by reducing combustion duration and knock intensity compared to conventional spark ignition (SI). Under JI, auto-ignition tends to occur at higher thermodynamic states with less heat loss, and the auto-ignition mode mainly depends on xi rather than epsilon as the pressure changes.
Article
Thermodynamics
Xin Liang, Yaozong Duan, Yunchu Fan, Zhen Huang, Dong Han
Summary: Blending ethanol with C5 esters into TPRF fuel improves octane rating, but different additives exhibit varying tendencies towards auto-ignition when blended on a molar basis.
INTERNATIONAL JOURNAL OF ENGINE RESEARCH
(2022)
Article
Energy & Fuels
Maryam M. Al-Taher, Christos Kalamaras, Mohammed A. Alqahtani, Fatimah S. Alomar
Summary: Gasoline compression ignition (GCI) technology improves thermal efficiency and reduces emissions compared to conventional spark ignition (SI) and diesel engines. This study proposes a method to control the ignition characteristics of gasoline by catalytic oxidation, enabling wider operation conditions for GCI engines.
Article
Engineering, Aerospace
Seonghyeon Park, Kyounghwan Lee, Hongjae Kang, Youngchul Park, Jongkwang Lee
Summary: In this study, a concept of novel hypergolic pairs with enhanced ignition performance is proposed. The introduction of oxidizing additives, such as LiNO3 and NH4NO3, in ionic liquid fuels and hydrogen peroxide was found to significantly enhance the ignition performance. Nitrate salts, serving as the oxidizing additives, have the potential to improve the properties of oxidizers by lowering the freezing point and shortening the ignition delay time of the hypergolic pairs.
Article
Energy & Fuels
Qimeng Duan, Xiaojun Yin, Xiaochen Wang, Hailiang Kou, Ke Zeng
Summary: Methanol is a competitive low carbon fuel for spark ignition engines, but knocking combustion remains an obstacle. Through experimental investigations, it was found that methanol direct injection strategy can effectively suppress knocking combustion, achieving more efficient combustion process.
Article
Chemistry, Organic
Andrew D. Ure, Aidan R. McDonald
Article
Chemistry, Organic
Andrew D. Ure, Isabel Abanades Lazaro, Michelle Cotter, Aidan R. McDonald
ORGANIC & BIOMOLECULAR CHEMISTRY
(2016)
Article
Chemistry, Multidisciplinary
Paolo Pirovano, Adriana M. Magherusan, Ciara McGlynn, Andrew Ure, Amy Lynes, Aidan R. McDonald
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2014)
Article
Thermodynamics
Karla Dussan, Sang Hee Won, Andrew D. Ure, Frederick L. Dryer, Stephen Dooley
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2019)
Article
Energy & Fuels
Andrew D. Ure, John E. O'Brien, Stephen Dooley