Experimental analysis of super-knock occurrence based on a spark ignition engine with high compression ratio Lei Zhou Rui Kang Haiqiao Wei Dengquan Feng Jianxiong Hua Jiaying Pan Rui Chen 2134/35203 https://repository.lboro.ac.uk/articles/journal_contribution/Experimental_analysis_of_super-knock_occurrence_based_on_a_spark_ignition_engine_with_high_compression_ratio/9228578 The super-knock phenomenon is a major obstacle for further improving the power density in SI engines. The objective of this paper is to experimentally investigating the mechanism involved in the occurrence of super-knock. In this work, a high compression ratio (CR = 13) coupled with advanced spark timings were employed to achieving intense or critical thermal-dynamic conditions to easily inducing the super-knock. The results show that super-knock can originate from spark ignition, which is different from previous results regarding pre-ignition. Changing the spark timing super-knock can be induced with very high pressure oscillation at the present high compression ratio. The high compression ratio could generate sufficiently high thermal-dynamic conditions to inducing the abnormal combustion. In this research, four combustion phenomena were observed. The present work indicates that there is a nonlinear relationship between knock intensity and knocking onset in terms of pressure profiles at different cycles. The super-knock or knock phenomena were dominantly induced by spark ignition, which were controlled by the pre-ignition after several cycles. Finally, the analysis of the mechanism of super-knock with severe pressure oscillation was employed based on the thermal explosion theory and cavity resonances. There are two possible auto-ignition combustion modes that can induce the intense pressure oscillation. 2018-10-08 08:16:30 Super-knock Pre-ignition High compression ratio Pressure oscillation Combustion modes Mechanical Engineering Engineering not elsewhere classified