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Title: Computational study of the pressure dependence of sequential auto-ignition for partial fuel stratification with gasoline

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Journal Article: Publisher's Accepted Manuscript
Journal Name:
Proceedings of the Combustion Institute
Additional Journal Information:
Journal Volume: 35; Journal Issue: 3; Related Information: CHORUS Timestamp: 2017-05-17 09:33:05; Journal ID: ISSN 1540-7489
Country of Publication:
United States

Citation Formats

Wolk, Benjamin, Chen, Jyh-Yuan, and Dec, John E. Computational study of the pressure dependence of sequential auto-ignition for partial fuel stratification with gasoline. United States: N. p., 2015. Web. doi:10.1016/j.proci.2014.05.023.
Wolk, Benjamin, Chen, Jyh-Yuan, & Dec, John E. Computational study of the pressure dependence of sequential auto-ignition for partial fuel stratification with gasoline. United States. doi:10.1016/j.proci.2014.05.023.
Wolk, Benjamin, Chen, Jyh-Yuan, and Dec, John E. 2015. "Computational study of the pressure dependence of sequential auto-ignition for partial fuel stratification with gasoline". United States. doi:10.1016/j.proci.2014.05.023.
title = {Computational study of the pressure dependence of sequential auto-ignition for partial fuel stratification with gasoline},
author = {Wolk, Benjamin and Chen, Jyh-Yuan and Dec, John E.},
abstractNote = {},
doi = {10.1016/j.proci.2014.05.023},
journal = {Proceedings of the Combustion Institute},
number = 3,
volume = 35,
place = {United States},
year = 2015,
month = 1

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1016/j.proci.2014.05.023

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Cited by: 4works
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  • Many research studies have shown that low temperature combustion in compression ignition engines has the ability to yield ultra-low NOx and soot emissions while maintaining high thermal efficiency. To achieve low temperature combustion, sufficient mixing time between the fuel and air in a globally dilute environment is required, thereby avoiding fuel-rich regions and reducing peak combustion temperatures, which significantly reduces soot and NOx formation, respectively. It has been demonstrated that achieving low temperature combustion with diesel fuel over a wide range of conditions is difficult because of its properties, namely, low volatility and high chemical reactivity. On the contrary, gasolinemore » has a high volatility and low chemical reactivity, meaning it is easier to achieve the amount of premixing time required prior to autoignition to achieve low temperature combustion. In order to achieve low temperature combustion while meeting other constraints, such as low pressure rise rates and maintaining control over the timing of combustion, in-cylinder fuel stratification has been widely investigated for gasoline low temperature combustion engines. The level of fuel stratification is, in reality, a continuum ranging from fully premixed (i.e. homogeneous charge of fuel and air) to heavily stratified, heterogeneous operation, such as diesel combustion. However, to illustrate the impact of fuel stratification on gasoline compression ignition, the authors have identified three representative operating strategies: partial, moderate, and heavy fuel stratification. Thus, this article provides an overview and perspective of the current research efforts to develop engine operating strategies for achieving gasoline low temperature combustion in a compression ignition engine via fuel stratification. In this paper, computational fluid dynamics modeling of the in-cylinder processes during the closed valve portion of the cycle was used to illustrate the opportunities and challenges associated with the various fuel stratification levels.« less
  • This paper reports on the dependence on hydrogen partial pressure of the entropy change of the hydrogen electrode reaction on platinum electrodes on yttria-stabilized zirconia that was estimated from measurements of the Seebeck coefficient of the yttria-stabilized zirconia. The entropy change of the oxygen reaction also was estimated by Seebeck coefficient measurements. The total entropy change of the reaction in a solid oxide fuel cell was calculated from the thermodynamic data. An empirical equation for the dependence of the entropy change of the hydrogen electrode reaction on hydrogen partial pressure was obtained from the observed entropy change of the oxygenmore » electrode and the total entropy change. The observed dependence of the entropy change of the hydrogen reaction on hydrogen partial pressure was in good agreement with the empirical equation.« less
  • Homogeneous charge compression ignition (HCCI) combustion with fully premixed charge is severely limited at high-load operation due to the rapid pressure-rise rates (PRR) which can lead to engine knock and potential engine damage. Recent studies have shown that two-stage ignition fuels possess a significant potential to reduce the combustion heat release rate, thus enabling higher load without knock.
  • We investigated the combustion process in a dual-fuel, reactivity-controlled compression-ignition (RCCI) engine using a combination of optical diagnostics and chemical kinetics modeling to explain the role of equivalence ratio, temperature, and fuel reactivity stratification for heat-release rate control. An optically accessible engine is operated in the RCCI combustion mode using gasoline primary reference fuels (PRF). A well-mixed charge of iso-octane (PRF = 100) is created by injecting fuel into the engine cylinder during the intake stroke using a gasoline-type direct injector. Later in the cycle, n-heptane (PRF = 0) is delivered through a centrally mounted diesel-type common-rail injector. This injectionmore » strategy generates stratification in equivalence ratio, fuel blend, and temperature. The first part of this study uses a high-speed camera to image the injection events and record high-temperature combustion chemiluminescence. Moreover, the chemiluminescence imaging showed that, at the operating condition studied in the present work, mixtures in the squish region ignite first, and the reaction zone proceeds inward toward the center of the combustion chamber. The second part of this study investigates the charge preparation of the RCCI strategy using planar laser-induced fluorescence (PLIF) of a fuel tracer under non-reacting conditions to quantify fuel concentration distributions prior to ignition. The fuel-tracer PLIF data show that the combustion event proceeds down gradients in the n-heptane distribution. The third part of the study uses chemical kinetics modeling over a range of mixtures spanning the distributions observed from the fuel-tracer fluorescence imaging to isolate the roles of temperature, equivalence ratio, and PRF number stratification. The simulations predict that PRF number stratification is the dominant factor controlling the ignition location and growth rate of the reaction zone. Equivalence ratio has a smaller, but still significant, influence. Lastly, temperature stratification had a negligible influence due to the NTC behavior of the PRF mixtures.« less