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Title: Numerical Investigation of a Central Fuel Property Hypothesis under Boosted Spark-ignition Conditions

Abstract

In the present work, a central fuel property hypothesis (CFPH), which states that fuel properties are sufficient to provide an indication of a fuel's performance irrespective of its chemical composition, was numerically investigated In particular, the objective of the study was to determine whether Research Octane Number (RON) and Motor Octane Number (MON), as fuel properties, are sufficient to describe a fuel's knock-limited performance under boosted spark-ignition (SI) conditions within the framework of CFPH. To this end, four TPRF-bioblendstock surrogates having different compositions but matched RON (= 98) and MON (= 90), were first generated using a non-linear regression model based on artificial neural network (ANN). Three unconventional bioblendstocks were included in the analysis: Di-isobutylene (DIB), Isobutanol and Anisole. Skeletal reaction mechanisms were generated for the TPRF-DIB, TPRF-isobutanol and TPRF-anisole blends from a detailed kinetic mechanism. Thereafter, numerical simulations were performed for the fuel surrogates using the skeletal mechanisms and a virtual cooperative fuel research (CFR) engine model, under a representative boosted operating condition. In the computational fluid dynamics (CFD) model, the G-equation approach was employed to track the turbulent flame front and the well-stirred reactor model combined with multi-zone binning strategy was used to capture auto-ignition in the end-gas.more » In addition, laminar flame speed was tabulated for each blend as a function of pressure, temperature and equivalence ratio a priori, and the lookup tables were used to prescribe laminar flame speed as an input to the G-equation model. Parametric spark timing sweeps were performed for each fuel blend to determine the corresponding knock-limited spark advance (KLSA) and 50% burn point (CA50) at the respective KLSA timing. It was observed that despite same RON, MON and engine operating conditions, the TPRF-Anisole blend exhibited markedly different knock-limited performance from the other three blends. This deviation from the octane index (DI) expectation was shown to be caused by differences in laminar flame speed (LFS). However; it was found that relatively large fuel-specific differences in LFS (> 20%) would have to be present to cause any appreciable deviation from the 01 framework. Otherwise, RON and MON would still be robust enough to predict a fuel's knock-limited performance.« 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) - Office of Vehicle Technologies (VTO)
OSTI Identifier:
1632337
DOE Contract Number:  
AC02-06CH11357
Resource Type:
Conference
Resource Relation:
Conference: 2019 ASME Internal Combustion Engine Division Fall Technical Conference, 10/20/19 - 10/23/19, Chicago, IL, US
Country of Publication:
United States
Language:
English

Citation Formats

Pal, Pinaki, Kalvakala, Krishna, Wu, Yunchao, McNenly, Matthew J, Lapointe, Simon, Whitesides, R, Lu, Tianfeng, Aggarwal, Suresh, and Som, Sibendu. Numerical Investigation of a Central Fuel Property Hypothesis under Boosted Spark-ignition Conditions. United States: N. p., 2020. Web. doi:10.1115/ICEF2019-7284.
Pal, Pinaki, Kalvakala, Krishna, Wu, Yunchao, McNenly, Matthew J, Lapointe, Simon, Whitesides, R, Lu, Tianfeng, Aggarwal, Suresh, & Som, Sibendu. Numerical Investigation of a Central Fuel Property Hypothesis under Boosted Spark-ignition Conditions. United States. doi:10.1115/ICEF2019-7284.
Pal, Pinaki, Kalvakala, Krishna, Wu, Yunchao, McNenly, Matthew J, Lapointe, Simon, Whitesides, R, Lu, Tianfeng, Aggarwal, Suresh, and Som, Sibendu. Wed . "Numerical Investigation of a Central Fuel Property Hypothesis under Boosted Spark-ignition Conditions". United States. doi:10.1115/ICEF2019-7284.
@article{osti_1632337,
title = {Numerical Investigation of a Central Fuel Property Hypothesis under Boosted Spark-ignition Conditions},
author = {Pal, Pinaki and Kalvakala, Krishna and Wu, Yunchao and McNenly, Matthew J and Lapointe, Simon and Whitesides, R and Lu, Tianfeng and Aggarwal, Suresh and Som, Sibendu},
abstractNote = {In the present work, a central fuel property hypothesis (CFPH), which states that fuel properties are sufficient to provide an indication of a fuel's performance irrespective of its chemical composition, was numerically investigated In particular, the objective of the study was to determine whether Research Octane Number (RON) and Motor Octane Number (MON), as fuel properties, are sufficient to describe a fuel's knock-limited performance under boosted spark-ignition (SI) conditions within the framework of CFPH. To this end, four TPRF-bioblendstock surrogates having different compositions but matched RON (= 98) and MON (= 90), were first generated using a non-linear regression model based on artificial neural network (ANN). Three unconventional bioblendstocks were included in the analysis: Di-isobutylene (DIB), Isobutanol and Anisole. Skeletal reaction mechanisms were generated for the TPRF-DIB, TPRF-isobutanol and TPRF-anisole blends from a detailed kinetic mechanism. Thereafter, numerical simulations were performed for the fuel surrogates using the skeletal mechanisms and a virtual cooperative fuel research (CFR) engine model, under a representative boosted operating condition. In the computational fluid dynamics (CFD) model, the G-equation approach was employed to track the turbulent flame front and the well-stirred reactor model combined with multi-zone binning strategy was used to capture auto-ignition in the end-gas. In addition, laminar flame speed was tabulated for each blend as a function of pressure, temperature and equivalence ratio a priori, and the lookup tables were used to prescribe laminar flame speed as an input to the G-equation model. Parametric spark timing sweeps were performed for each fuel blend to determine the corresponding knock-limited spark advance (KLSA) and 50% burn point (CA50) at the respective KLSA timing. It was observed that despite same RON, MON and engine operating conditions, the TPRF-Anisole blend exhibited markedly different knock-limited performance from the other three blends. This deviation from the octane index (DI) expectation was shown to be caused by differences in laminar flame speed (LFS). However; it was found that relatively large fuel-specific differences in LFS (> 20%) would have to be present to cause any appreciable deviation from the 01 framework. Otherwise, RON and MON would still be robust enough to predict a fuel's knock-limited performance.},
doi = {10.1115/ICEF2019-7284},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2020},
month = {1}
}

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