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Experimental analysis of super-knock occurrence based on a spark ignition engine with high compression ratio

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journal contribution
posted on 08.10.2018 by Lei Zhou, Rui Kang, Haiqiao Wei, Dengquan Feng, Jianxiong Hua, Jiaying Pan, Rui Chen
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.

Funding

This study is supported by the National Natural Science Foundation of China (Grant No. 91641203, 91741119, 51476114).

History

School

  • Aeronautical, Automotive, Chemical and Materials Engineering

Department

  • Aeronautical and Automotive Engineering

Published in

Energy

Citation

ZHOU, L. ... et al, 2018. Experimental analysis of super-knock occurrence based on a spark ignition engine with high compression ratio. Energy, 165, Part B, pp.68-75.

Publisher

© Elsevier

Version

AM (Accepted Manuscript)

Publisher statement

This paper was accepted for publication in the journal Energy and the definitive published version is available at https://doi.org/10.1016/j.energy.2018.09.166.

Acceptance date

25/09/2018

Publication date

2018-09-27

ISSN

0360-5442

Language

en

Exports