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Title: Insights into Engine Knock: Comparisons of Knock Metrics across Ranges of Intake Temperature and Pressure in the CFR Engine

Abstract

Of late there has been a resurgence in studies investigating parameters that quantify combustion knock in both standardized platforms and modern spark-ignition engines. However, it is still unclear how metrics such as knock (octane) rating, knock onset, and knock intensity are related and how fuels behave according to these metrics across a range of conditions. As part of an ongoing study, the air supply system of a standard Cooperative Fuel Research (CFR) F1/F2 engine was modified to allow mild levels of intake air boosting while staying true to its intended purpose of being the standard device for American Society for Testing and Materials (ASTM)-specified knock rating or octane number tests. For instance, the carburation system and intake air heating manifold are not altered, but the engine was equipped with cylinder pressure transducers to enable both logging of the standard knockmeter readout and state-of-the-art indicated data. For this study, the engine was operated using primary reference fuel 90 (PRF90) at 600 rpm, first following the procedures of the ASTM D2699 research octane number test protocol in order to define the geometric compression ratio set point for standard knock number. Thereafter, compression ratio sweeps were conducted at intake temperatures ranging from 30more » to 150°C and intake air boost extending from 0 to 0.3 bar above ambient. The resulting operating map provided a broad envelope of compressed in-cylinder conditions relevant to modern spark-ignition engines. Detailed analysis of the indicated data highlighted a poor correlation between established knock intensity metrics and the knockmeter reading, which is used to characterize a fuel’s octane number. It was further found that the auto-ignition characteristics of PRF90 could be perturbed by means of intake air boosting and heating without being captured by the knockmeter reading.« less

Authors:
; ; ; ;
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Energy Efficiency and Renewable Energy (EERE) - Bioenergy Technologies Office (BETO); USDOE Office of Energy Efficiency and Renewable Energy (EERE) - Office of Vehicle Technology
OSTI Identifier:
1501887
DOE Contract Number:  
AC02-06CH11357
Resource Type:
Conference
Resource Relation:
Journal Volume: 1; Conference: 2018 SAE World Congress Experience, 04/10/18 - 04/12/18, Detroit, MI, US
Country of Publication:
United States
Language:
English

Citation Formats

Rockstroh, Toby, Kolodziej, Christopher P., Jespersen, Mads C., Goldsborough, S. Scott, and Wallner, Thomas. Insights into Engine Knock: Comparisons of Knock Metrics across Ranges of Intake Temperature and Pressure in the CFR Engine. United States: N. p., 2018. Web. doi:10.4271/2018-01-0210.
Rockstroh, Toby, Kolodziej, Christopher P., Jespersen, Mads C., Goldsborough, S. Scott, & Wallner, Thomas. Insights into Engine Knock: Comparisons of Knock Metrics across Ranges of Intake Temperature and Pressure in the CFR Engine. United States. doi:10.4271/2018-01-0210.
Rockstroh, Toby, Kolodziej, Christopher P., Jespersen, Mads C., Goldsborough, S. Scott, and Wallner, Thomas. Tue . "Insights into Engine Knock: Comparisons of Knock Metrics across Ranges of Intake Temperature and Pressure in the CFR Engine". United States. doi:10.4271/2018-01-0210.
@article{osti_1501887,
title = {Insights into Engine Knock: Comparisons of Knock Metrics across Ranges of Intake Temperature and Pressure in the CFR Engine},
author = {Rockstroh, Toby and Kolodziej, Christopher P. and Jespersen, Mads C. and Goldsborough, S. Scott and Wallner, Thomas},
abstractNote = {Of late there has been a resurgence in studies investigating parameters that quantify combustion knock in both standardized platforms and modern spark-ignition engines. However, it is still unclear how metrics such as knock (octane) rating, knock onset, and knock intensity are related and how fuels behave according to these metrics across a range of conditions. As part of an ongoing study, the air supply system of a standard Cooperative Fuel Research (CFR) F1/F2 engine was modified to allow mild levels of intake air boosting while staying true to its intended purpose of being the standard device for American Society for Testing and Materials (ASTM)-specified knock rating or octane number tests. For instance, the carburation system and intake air heating manifold are not altered, but the engine was equipped with cylinder pressure transducers to enable both logging of the standard knockmeter readout and state-of-the-art indicated data. For this study, the engine was operated using primary reference fuel 90 (PRF90) at 600 rpm, first following the procedures of the ASTM D2699 research octane number test protocol in order to define the geometric compression ratio set point for standard knock number. Thereafter, compression ratio sweeps were conducted at intake temperatures ranging from 30 to 150°C and intake air boost extending from 0 to 0.3 bar above ambient. The resulting operating map provided a broad envelope of compressed in-cylinder conditions relevant to modern spark-ignition engines. Detailed analysis of the indicated data highlighted a poor correlation between established knock intensity metrics and the knockmeter reading, which is used to characterize a fuel’s octane number. It was further found that the auto-ignition characteristics of PRF90 could be perturbed by means of intake air boosting and heating without being captured by the knockmeter reading.},
doi = {10.4271/2018-01-0210},
journal = {},
issn = {0148--7191},
number = ,
volume = 1,
place = {United States},
year = {2018},
month = {4}
}

Conference:
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