Fuel-specific differences in exhaust gas recirculation (EGR) dilution tolerance are studied in a modern, direct-injection single-cylinder research engine. A total of 6 model fuel blends are examined at a constant research octane number (RON) of 95 using n-heptane, isooctane, toluene, and ethanol. Laminar flame speeds for these mixtures, which are calculated using two different methods (an energy fraction mixing rule and a detailed kinetic simulation), span a range of about 6 cm/s. A nominal load of 350 kPa IMEPg at 2000 rpm is maintained with constant fueling and varying CA50 from 8-20 CAD aTDCf. EGR is increased until a COV of IMEP of 5% is reached. The results illustrate that flame speed affects EGR dilution tolerance; fuels with increased flame speeds have increased EGR tolerance. Specifically, flame speed correlates most closely to the initial flame kernel growth, measured as the time of ignition to 5% mass fraction burned. The effect of the latent heat of vaporization (HoV) on the flame speed is taken into account for the ethanol-containing fuels. At a 30 vol% blend level, the increased enthalpy of vaporization of ethanol compared to conventional hydrocarbons can decrease the temperature at the time of ignition by a maximum of 15°C, which can account for up to a 3.5 cm/s decrease in flame speed. The ethanol-containing fuels, however, still exhibit a flame speed advantage, and a dilution tolerance advantage over the slower flame-speed fuels. The fuel-specific differences in dilution tolerance are significant at the condition examined, allowing for a 50% relative increase in EGR (4% absolute difference in EGR) at a constant COV of IMEP of 3%.


    Access

    Check access

    Check availability in my library

    Order at Subito €


    Export, share and cite



    Title :

    Effects of Fuel Composition on EGR Dilution Tolerance in Spark Ignited Engines


    Additional title:

    Sae Int. J. Engines


    Contributors:

    Conference:

    SAE 2016 World Congress and Exhibition ; 2016


    Published in:

    Publication date :

    2016-04-05


    Size :

    13 pages




    Type of media :

    Conference paper


    Type of material :

    Print


    Language :

    English




    Effects of Fuel Composition on EGR Dilution Tolerance in Spark Ignited Engines

    Szybist, James P. / Splitter, Derek | British Library Conference Proceedings | 2016


    FUEL INJECTION for Spark-Ignited Automotive Engines

    VAN OVERBEKE, C. W. / LANGE, G. M. | SAE Technical Papers | 1949


    Closed-loop electronic fuel injection for spark-ignited engines

    Terreni, P. / Gentili, R. | Tema Archive | 1986


    Spark-ignited engines from Uni Diesel

    Uni Diesel,FR | Automotive engineering | 1987


    Effects of Fuel Composition on Auto-Ignition and Detonation Development in Boosted Spark-Ignited Engines

    Nicolle, Andre / Singh, Eshan / Gorbatenko, Inna et al. | SAE Technical Papers | 2021