Effects of pre-spark heat release on engine knock limit [electronic resource]
Si Engines; Knock; Low Temperature Chemistry; Pre Spark Heat Release; Chemical Kinetics.
Saved in:
| Online Access: |
Online Access (via OSTI) |
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| Corporate Author: | |
| Format: | Government Document Electronic eBook |
| Language: | English |
| Published: |
Washington, D.C. : Oak Ridge, Tenn. :
United States. Department of Energy. Office of Energy Efficiency and Renewable Energy ; distributed by the Office of Scientific and Technical Information, U.S. Department of Energy,
2018.
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| Subjects: |
| Summary: | Si Engines; Knock; Low Temperature Chemistry; Pre Spark Heat Release; Chemical Kinetics. |
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| Abstract: | It is well known that spark ignited engine efficiency is limited by end gas autoignition, commonly known as knock. This study focuses on a recently discovered phenomena, pre-spark heat release (PSHR) due to low-temperature chemistry, and its impact on knock behavior. Boosted operating conditions are more common as engines are downsizing and downspeeding in efforts to increase fuel economy and prone to PSHR. Experiments were prone at fixed fueling and air fuel ratio for a range of intake temperature that spanned the threshold for PSHR. It was found that when PSHR occurred, the knock-limited combustion phasing was insensitive to intake temperature; higher intake temperatures did not require retarded timings as it is usual. Inspection of the temperature-pressure history overlaid on ignition delay contours allow the results to be explained. The temperature rise from the low-temperature reactions moves the end gas state into the negative temperature coefficient (NTC) region, which terminates the heat release reactions. As a result, the end gas then resides in the long ignition delay peninsula, which inhibits knock. |
| Item Description: | Published through SciTech Connect. 06/28/2018. Proceedings of the Combustion Institute 37 4 ISSN 1540-7489 AM. Derek A. Splitter; Arthur Gilliam; James P. Szybist; Jaal B. Ghandhi. |
| Physical Description: | p. 4893-4900 : digital, PDF file. |