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Title: Knock Mitigation Effectiveness of EGR across the Pressure-Temperature Domain

Abstract

Exhaust gas recirculation (EGR) has been shown to enable efficiency improvements in SI engines through multiple different mechanisms, including decreasing the knock propensity at high load, which allows higher compression ratio. While many of the benefits of EGR are applicable to both low and high power density engines, including reductions in pumping work and improved specific heat ratio, the knock benefits and corresponding compression ratio increases have been limited to low power density naturally aspirated engines primarily intended for hybrid vehicle architectures. An earlier study [1] indicated that there may be a kinetic limitation for the ability of EGR to mitigate knock under these conditions, but that study only considered a small number of conditions. In this investigation, we expand on that study while also providing data for model validation for the new light-duty combustion consortium from the U.S. Department of Energy: Partnership for Advancing Combustion Engines (PACE). In this investigation, the effectiveness of EGR to mitigate knock is studied with regards to the effect of engine speed (1,500 and 3,000 rpm), changing trajectory in the pressure-temperature domain by varying the intake manifold temperature (35, 60, and 90 deg C), and by considering the effect of minor species by studyingmore » the effect of untreated EGR vs. EGR that has been treated by an automotive three-way catalyst. Additionally, to increase the relevance of these data for future modeling studies, the performance of the full boiling range gasoline was compared relative to a surrogate formulation. The study found that the fuel surrogate performs well, confirmed the kinetic limitations of EGR to mitigate knock under boost, and showed improvements in EGR performance with catalyzed EGR.« less

Authors:
ORCiD logo [1]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Transportation Office. Vehicle Technologies Office
OSTI Identifier:
1659613
Grant/Contract Number:  
AC05-00OR22725
Resource Type:
Accepted Manuscript
Journal Name:
SAE International Journal of Advances and Current Practices in Mobility
Additional Journal Information:
Journal Volume: 1; Journal Issue: 1; Journal ID: ISSN 2641-9645
Publisher:
SAE International
Country of Publication:
United States
Language:
English
Subject:
42 ENGINEERING

Citation Formats

Szybist, James. Knock Mitigation Effectiveness of EGR across the Pressure-Temperature Domain. United States: N. p., 2020. Web. https://doi.org/10.4271/2020-01-2053.
Szybist, James. Knock Mitigation Effectiveness of EGR across the Pressure-Temperature Domain. United States. https://doi.org/10.4271/2020-01-2053
Szybist, James. Tue . "Knock Mitigation Effectiveness of EGR across the Pressure-Temperature Domain". United States. https://doi.org/10.4271/2020-01-2053.
@article{osti_1659613,
title = {Knock Mitigation Effectiveness of EGR across the Pressure-Temperature Domain},
author = {Szybist, James},
abstractNote = {Exhaust gas recirculation (EGR) has been shown to enable efficiency improvements in SI engines through multiple different mechanisms, including decreasing the knock propensity at high load, which allows higher compression ratio. While many of the benefits of EGR are applicable to both low and high power density engines, including reductions in pumping work and improved specific heat ratio, the knock benefits and corresponding compression ratio increases have been limited to low power density naturally aspirated engines primarily intended for hybrid vehicle architectures. An earlier study [1] indicated that there may be a kinetic limitation for the ability of EGR to mitigate knock under these conditions, but that study only considered a small number of conditions. In this investigation, we expand on that study while also providing data for model validation for the new light-duty combustion consortium from the U.S. Department of Energy: Partnership for Advancing Combustion Engines (PACE). In this investigation, the effectiveness of EGR to mitigate knock is studied with regards to the effect of engine speed (1,500 and 3,000 rpm), changing trajectory in the pressure-temperature domain by varying the intake manifold temperature (35, 60, and 90 deg C), and by considering the effect of minor species by studying the effect of untreated EGR vs. EGR that has been treated by an automotive three-way catalyst. Additionally, to increase the relevance of these data for future modeling studies, the performance of the full boiling range gasoline was compared relative to a surrogate formulation. The study found that the fuel surrogate performs well, confirmed the kinetic limitations of EGR to mitigate knock under boost, and showed improvements in EGR performance with catalyzed EGR.},
doi = {10.4271/2020-01-2053},
journal = {SAE International Journal of Advances and Current Practices in Mobility},
number = 1,
volume = 1,
place = {United States},
year = {2020},
month = {9}
}

Journal Article:
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This content will become publicly available on September 15, 2021
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