Determination of knock start for any engine tuning remains a difficult work for many engine manufacturers. This study investigates different combinations of existing knock indices in order to produce an upgraded indicator easier to calibrate. Experiments were conducted on a single-cylinder gas engine bounded to combined heat and power (CHP). Effects of spark advance, volumetric efficiency and equivalent ratio are studied under constant speed operation. The ratio IMPO / MAPO (with IMPO defined as the Integral of Modulus of Pressure Oscillation and MAPO as the Maximum Amplitude of Pressure Oscillation) is proposed as a suitable indicator. In any engine setting, it remains constant under non knocking conditions. When knock occurs, a model deduced from dimensionless analysis allows to determine the oversteps of Knock Limited Spark Timing from IMPO / MAPO measurements with an accuracy lower than 1 CA.


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    Title :

    Experimental Determination of Knock in Gas SI Engine


    Additional title:

    Sae Technical Papers


    Contributors:
    Brecq, G. (author) / Bellettre, J. (author) / Tazerout, M. (author)

    Conference:

    SIAT 2001 ; 2001



    Publication date :

    2001-11-01




    Type of media :

    Conference paper


    Type of material :

    Print


    Language :

    English




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