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The effect of iso-octane addition on combustion and emission characteristics of a HCCI engine fueled with n-heptane / Cosmin E. Dumitrescu in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 133 N° 11 (Novembre 2011) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 133 N° 11 (Novembre 2011) . - 07 p. Titre : The effect of iso-octane addition on combustion and emission characteristics of a HCCI engine fueled with n-heptane Type de document : texte imprimé Auteurs : Cosmin E. Dumitrescu, Auteur ; Hongsheng Guo, Auteur ; Vahid Hosseini, Auteur Année de publication : 2012 Article en page(s) : 07 p. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Air  pollution  Combustion  Fuel  Ignition  Internal  combustion  engines Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : This paper investigates the effects of iso-octane addition on the combustion and emission characteristics of a single-cylinder, variable compression ratio, homogeneous charge compression ignition (HCCI) engine fueled with n-heptane. The engine was operated with four fuel blends containing up to 50% iso-octane by liquid volume at 900 rpm, 50:1 air-to-fuel ratio, no exhaust gas recirculation, and an intake mixture temperature of 30°C. A detailed analysis of the regulated and unregulated emissions was performed including validation of the experimental results using a multizone model with detailed fuel chemistry. The results show that iso-octane addition reduced HCCI combustion efficiency and retarded the combustion phasing. The range of engine compression ratios where satisfactory HCCI combustion occurred was found to narrow with increasing iso-octane percentage in the fuel. NOx emissions increased with iso-octane addition at advanced combustion phasing, but the influence of iso-octane addition was negligible once CA50 (crank angle position at which 50% heat is released) was close to or after top dead center. The total unburned hydrocarbons (THC) in the exhaust consisted primarily of alkanes, alkenes, and oxygenated hydrocarbons. The percentage of alkanes, the dominant class of THC emissions, was found to be relatively constant. The alkanes were composed primarily of unburned fuel compounds, and iso-octane addition monotonically increased and decreased the iso-octane and n-heptane percentages in the THC emissions, respectively. The percentage of alkenes in the THC was not significantly affected by iso-octane addition. Iso-octane addition increased the percentage of oxygenated hydrocarbons. Small quantities of cycloalkanes and aromatics were detected when the iso-octane percentage was increased beyond 30%. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...] [article] The effect of iso-octane addition on combustion and emission characteristics of a HCCI engine fueled with n-heptane [texte imprimé] / Cosmin E. Dumitrescu, Auteur ; Hongsheng Guo, Auteur ; Vahid Hosseini, Auteur . - 2012 . - 07 p. Génie Mécanique Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 133 N° 11 (Novembre 2011) . - 07 p. Mots-clés : Air  pollution  Combustion  Fuel  Ignition  Internal  combustion  engines Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : This paper investigates the effects of iso-octane addition on the combustion and emission characteristics of a single-cylinder, variable compression ratio, homogeneous charge compression ignition (HCCI) engine fueled with n-heptane. The engine was operated with four fuel blends containing up to 50% iso-octane by liquid volume at 900 rpm, 50:1 air-to-fuel ratio, no exhaust gas recirculation, and an intake mixture temperature of 30°C. A detailed analysis of the regulated and unregulated emissions was performed including validation of the experimental results using a multizone model with detailed fuel chemistry. The results show that iso-octane addition reduced HCCI combustion efficiency and retarded the combustion phasing. The range of engine compression ratios where satisfactory HCCI combustion occurred was found to narrow with increasing iso-octane percentage in the fuel. NOx emissions increased with iso-octane addition at advanced combustion phasing, but the influence of iso-octane addition was negligible once CA50 (crank angle position at which 50% heat is released) was close to or after top dead center. The total unburned hydrocarbons (THC) in the exhaust consisted primarily of alkanes, alkenes, and oxygenated hydrocarbons. The percentage of alkanes, the dominant class of THC emissions, was found to be relatively constant. The alkanes were composed primarily of unburned fuel compounds, and iso-octane addition monotonically increased and decreased the iso-octane and n-heptane percentages in the THC emissions, respectively. The percentage of alkenes in the THC was not significantly affected by iso-octane addition. Iso-octane addition increased the percentage of oxygenated hydrocarbons. Small quantities of cycloalkanes and aromatics were detected when the iso-octane percentage was increased beyond 30%. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...]