Abstract
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.
| Original language | English |
|---|---|
| Pages (from-to) | 1649-1655 |
| Number of pages | 7 |
| Journal | Applied Energy |
| Volume | 88 |
| Issue number | 5 |
| DOIs | |
| State | Published - May 2011 |
Funding
We would like to thank the two anonymous reviewers whose constructive comments helped significantly improve the manuscript. This work was supported by the US Department of Energy, Office of Energy Efficiency and Renewable Energy. G. Litak would like to thank Prof. A.K. Sen and Prof. C.S. Daw for their hospitality during his visits to Indiana and Oak Ridge.
| Funders | Funder number |
|---|---|
| US Department of Energy | |
| Office of Energy Efficiency and Renewable Energy |
Keywords
- Homogeneous charge compression ignition
- Internal combustion engine
- Spark ignition