Multi-scale dynamics for a lean-burn spark ignition natural gas engine under low load conditions
(2023) In Fuel 332.- Abstract
This work investigates the multi-scale dynamics of the combustion system in a lean-burn spark ignition natural gas engine using different gas injection timings (GIT). The in-cylinder pressure time series are measured, and the indicated mean effective pressure (IMEP) time series are calculated. The influence of GIT on the combustion system is investigated through wavelet analysis, multi-resolution analysis, and the return maps with the GIT covering from 0 to 90°CA after top dead center at the intake stage. Results show that the combustion system has multi-scale chaotic characteristics, and it is sensitive to the change of GIT. The unreasonable GIT will result in serious combustion variations. Meanwhile, the combustion instability of the... (More)
This work investigates the multi-scale dynamics of the combustion system in a lean-burn spark ignition natural gas engine using different gas injection timings (GIT). The in-cylinder pressure time series are measured, and the indicated mean effective pressure (IMEP) time series are calculated. The influence of GIT on the combustion system is investigated through wavelet analysis, multi-resolution analysis, and the return maps with the GIT covering from 0 to 90°CA after top dead center at the intake stage. Results show that the combustion system has multi-scale chaotic characteristics, and it is sensitive to the change of GIT. The unreasonable GIT will result in serious combustion variations. Meanwhile, the combustion instability of the engine evolves on multiple time scales, showing evident multi-scale oscillation characteristics. All the wavelet power spectrums (WPS) present the characteristics of intermittent short-time periodic oscillations and persistent large-scale periodic oscillations concealed inside the IMEP time series. When the GIT approaches the medium value, the persistence of large-scale periodic oscillations is weakened, while the characteristics of high-frequency intermittent oscillations are enhanced. Under all working conditions, the contribution rate of high-frequency signal D1 decomposed by the IMEP time series to the overall time series fluctuation is about 40% or even higher. The contribution rate of the signal D1 also increases with the aggravation of combustion instability. The return map structures of high-frequency signals D1 and D2 show bifurcation structures, and the bifurcation characteristics of the signal D1 are more evident under medium GIT conditions, indicating a certain correlation between the 2–8 engine cycles, and the correlation between the adjacent engine cycles is stronger. The deterministic relationship between the multiple engine cycles found can help in developing a more reasonable and efficient combustion control strategy, which provides a theoretical basis for improving the stability of a natural gas engine.
(Less)
- author
- He, Shuai Feng ; Tunestål, Per LU ; Ding, Su Fen ; Ding, Shun Liang ; Gao, Jian She and Song, En Zhe
- organization
- publishing date
- 2023-01-15
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- Gas injection timing, Multi-resolution analysis, Multi-scale dynamics, Natural gas engine, Wavelet analysis
- in
- Fuel
- volume
- 332
- article number
- 126239
- publisher
- Elsevier
- external identifiers
-
- scopus:85139821445
- ISSN
- 0016-2361
- DOI
- 10.1016/j.fuel.2022.126239
- language
- English
- LU publication?
- yes
- id
- 15f4005f-679f-4fd6-b639-f6876d8e82bb
- date added to LUP
- 2023-01-23 13:16:03
- date last changed
- 2023-10-05 12:55:53
@article{15f4005f-679f-4fd6-b639-f6876d8e82bb,
abstract = {{<p>This work investigates the multi-scale dynamics of the combustion system in a lean-burn spark ignition natural gas engine using different gas injection timings (GIT). The in-cylinder pressure time series are measured, and the indicated mean effective pressure (IMEP) time series are calculated. The influence of GIT on the combustion system is investigated through wavelet analysis, multi-resolution analysis, and the return maps with the GIT covering from 0 to 90°CA after top dead center at the intake stage. Results show that the combustion system has multi-scale chaotic characteristics, and it is sensitive to the change of GIT. The unreasonable GIT will result in serious combustion variations. Meanwhile, the combustion instability of the engine evolves on multiple time scales, showing evident multi-scale oscillation characteristics. All the wavelet power spectrums (WPS) present the characteristics of intermittent short-time periodic oscillations and persistent large-scale periodic oscillations concealed inside the IMEP time series. When the GIT approaches the medium value, the persistence of large-scale periodic oscillations is weakened, while the characteristics of high-frequency intermittent oscillations are enhanced. Under all working conditions, the contribution rate of high-frequency signal D<sub>1</sub> decomposed by the IMEP time series to the overall time series fluctuation is about 40% or even higher. The contribution rate of the signal D<sub>1</sub> also increases with the aggravation of combustion instability. The return map structures of high-frequency signals D<sub>1</sub> and D<sub>2</sub> show bifurcation structures, and the bifurcation characteristics of the signal D<sub>1</sub> are more evident under medium GIT conditions, indicating a certain correlation between the 2–8 engine cycles, and the correlation between the adjacent engine cycles is stronger. The deterministic relationship between the multiple engine cycles found can help in developing a more reasonable and efficient combustion control strategy, which provides a theoretical basis for improving the stability of a natural gas engine.</p>}},
author = {{He, Shuai Feng and Tunestål, Per and Ding, Su Fen and Ding, Shun Liang and Gao, Jian She and Song, En Zhe}},
issn = {{0016-2361}},
keywords = {{Gas injection timing; Multi-resolution analysis; Multi-scale dynamics; Natural gas engine; Wavelet analysis}},
language = {{eng}},
month = {{01}},
publisher = {{Elsevier}},
series = {{Fuel}},
title = {{Multi-scale dynamics for a lean-burn spark ignition natural gas engine under low load conditions}},
url = {{http://dx.doi.org/10.1016/j.fuel.2022.126239}},
doi = {{10.1016/j.fuel.2022.126239}},
volume = {{332}},
year = {{2023}},
}