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The nature of "superknock" and its origins in SI engines
KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
2009 (English)In: Internal combustion engines: performance, fuel economy and emissions, Institution of Mechanical Engineers, 2009, 259-269 p.Conference paper (Refereed)
Abstract [en]

Extremely high knock intensities are observed occasionally in turbo charged spark ignition (SI) engines. Such events have been informally described as "Super knock" and are often associated with pre-ignition. Knock is initiated by auto ignition at one or more "hot spots". The mode of propagation of the resulting pressure wave depends on the propagation velocity of the auto ignitive front. When this becomes coupled with the acoustic wave, a localised detonation begins to develop, resulting in a very high rate of pressure rise. It is shown, through semi quantitative analysis including chemical kinetic calculations, that developing detonation becomes more likely when end-gas pressures and temperatures increase and might be the reason for "Super knock".

Place, publisher, year, edition, pages
Institution of Mechanical Engineers, 2009. 259-269 p.
Keyword [en]
Auto-ignition, Chemical kinetics, Gas pressures, High rate, Hot spot, Knock intensity, Pressure waves, Propagation velocities, Semi-quantitative analysis, SI Engines, Spark ignition engines, Acoustics, Combustion knock, Detonation, Engines, Ignition, Fuel economy
National Category
Vehicle Engineering
URN: urn:nbn:se:kth:diva-152417ScopusID: 2-s2.0-77952390994ISBN: 978-184334607-4OAI: diva2:750798
IMechE's Internal Combustion Engines: Performance, Fuel Economy and Emissions Conference, 8 December 2009 through 9 December 2009, London, United Kingdom

QC 20140930

Available from: 2014-09-30 Created: 2014-09-26 Last updated: 2014-09-30Bibliographically approved

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