Analysis of heat release dynamics in an internal combustion engine using multifractals and wavelets

Journal Article · Fri Jan 01 04:00:00 EST 2010 · Applied Energy

DOI:https://doi.org/10.1016/j.apenergy.2009.11.009· OSTI ID:1036658

Sen, Asok K ^[1]; Litak, Grzegorz ^[2]; FINNEY, Charles E A ^[3]; Daw, C Stuart ^[3]; Wagner, Robert M ^[3]

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1. Indiana University
2. Technical University of Lublin
3. ORNL

In this paper we analyze data from previously reported experimental measurements of cycle-to-cycle combustion variations in a lean-fueled, multi-cylinder spark-ignition (SI) engine. We characterize the changes in the observed combustion dynamics with as-fed fuel air ratio using conventional histograms and statistical moments, and we further characterize the shifts in combustion complexity in terms of multifractals and wavelet decomposition. Changes in the conventional statistics and multifractal structure indicate trends with fuel air ratio that parallel earlier reported observations. Wavelet decompositions reveal persistent, non-stochastic oscillation modes at higher fuel air ratios that were not obvious in previous analyses. Recognition of these long-time-scale, non-stochastic oscillations is expected to be useful for improving modelling and control of engine combustion variations and multi-cylinder balancing.

• Research Organization: Oak Ridge National Laboratory (ORNL); Fuels, Engines and Emissions Research Center
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1036658
• Journal Information: Applied Energy, Journal Name: Applied Energy Journal Issue: 5 Vol. 87; ISSN 0306-2619
• Country of Publication: United States
• Language: English