Characteristics of cyclic heat release variability in the transition from spark ignition to HCCI in a gasoline engine

Journal Article · Sat Jan 01 04:00:00 EST 2011 · Applied Energy

DOI:https://doi.org/10.1016/j.apenergy.2010.11.040· OSTI ID:1036663

Sen, Asok K ^[1]; Litak, Grzegorz ^[2]; Edwards, Kevin Dean ^[3]; 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

We study selected examples of previously published cyclic heat-release measurements from a single-cylinder gasoline engine as stepwise valve timing adjustments were made to shift from spark ignited (SI) combustion to homogeneous charge compression ignition (HCCI). Wavelet analysis of the time series, combined with conventional statistics and multifractal analysis, revealed previously undocumented features in the combustion variability as the shift occurred. In the spark-ignition combustion mode, the heat-release variations were very small in amplitude and exhibited more persistent low-frequency oscillations with intermittent high-frequency bursts. In the HCCI combustion mode, the amplitude of the heat-release variations again was small and involved mainly low-frequency oscillations. At intermediate states between SI and HCCI, a wide range of very large-amplitude oscillations occurred, including both persistent low-frequency periodicities and intermittent high-frequency bursts. It appears from these results that real-time wavelet decomposition of engine cylinder pressure measurements may be useful for on-board tracking of SI HCCI combustion regime shifts.

• Research Organization: Oak Ridge National Laboratory (ORNL); Fuels, Engines and Emissions Research Center
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1036663
• Journal Information: Applied Energy, Journal Name: Applied Energy Journal Issue: 5 Vol. 88; ISSN 0306-2619; ISSN APENDX
• Country of Publication: United States
• Language: English

Related Subjects

33 ADVANCED PROPULSION SYSTEMS
AMPLITUDES
COMBUSTION
COMPRESSION
ENGINES
IGNITION
INTERNAL COMBUSTION ENGINES
OSCILLATIONS
PRESSURE MEASUREMENT
STATISTICS
VALVES