High SI engine part load efficiencies require simultaneously part load dethrottling and small burn durations. The latter ones necessitate – in case of SI combustion in its prevalent appearance – minimum residual burnt gas and high in-cylinder turbulence generated by charge motion. These demands can especially be fulfilled by variable valve trains with asymmetric valve actuation, also called intake valve lift phasing with intake port deactivation as its borderline case. They can combine early intake valve closing and strong charge motion generation, which contains both tumble and swirl.

    In order to enable phenomenological burn rate prediction via 0D/1D engine simulation for these cases, a quasi-dimensional charge motion and turbulence model has been developed. The generation of charge motion is modeled by use of charge motion coefficients which should be derived from at least one engine operation point calculated by 3D-CFD. The conversion of tumble and swirl to turbulence around top dead center is predicted by a quasi-dimensional flow shear model.

    An additional model part is also presented considering an approach for the impact of direct fuel injection on tumble and turbulence. The model development was based on 3D CFD simulations.


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    Title :

    A Quasi-Dimensional Charge Motion and Turbulence Model for Spark Injection Engines with Fully Variable Valve Train and Direct Fuel Injection


    Additional title:

    Proceedings


    Contributors:


    Publication date :

    2020-01-27


    Size :

    16 pages





    Type of media :

    Article/Chapter (Book)


    Type of material :

    Electronic Resource


    Language :

    German