The design of diesel engine piston bowls plays a fundamental role in the optimization of the combustion process, to achieve ultra-low soot emissions. With this aim, an innovative piston bowl design for a 1.6-liter light-duty diesel engine was developed through a steel-based additive manufacturing (AM) technique, featuring both a sharp step and radial bumps in the inner bowl rim. The potential benefits of the proposed hybrid bowl were assessed through a validated three-dimensional computational fluid dynamics (3D-CFD) model, including a calibrated spray model and detailed chemistry. Firstly, the optimal spray targeting was identified for the novel hybrid bowl over different injector protrusions and two swirl ratio (SR) levels. Considering the optimal spray targeting, an analysis of the combustion process was carried out over different engine working points, both in terms of flame-wall interaction and soot formation. At rated power engine operating conditions, the hybrid bowl highlighted faster mixing-controlled combustion due to the reduced flame-to-flame interaction and the higher air entrainment into the flame front. At partial-load operating points, the hybrid bowl showed a remarkable soot reduction in comparison with the re-entrant bowl due to a more intense soot oxidation rate in the late combustion phase. Moreover, for the hybrid bowl, a robust Exhaust Gas Recirculation (EGR) tolerance was highlighted, leading to a flat soot-brake-specific oxides of nitrogen (BSNOx) trade-off. At constant BSNOx, a 70% soot reduction was achieved without any detrimental effect on fuel consumption, suggesting the high potential of the proposed innovative bowl for soot attenuation.


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    Title :

    Numerical Assessment of Additive Manufacturing-Enabled Innovative Piston Bowl Design for a Light-Duty Diesel Engine Achieving Ultra-Low Engine-Out Soot Emissions


    Additional title:

    Sae Int. J. Engines



    Published in:

    Publication date :

    2021-09-28


    Size :

    17 pages




    Type of media :

    Conference paper


    Type of material :

    Print


    Language :

    English





    An Assessment of Two Piston Bowl Concepts in a Medium-Duty Diesel Engine

    Kurtz, E.M. / Styron, J. / Society of Automotive Engineers | British Library Conference Proceedings | 2012


    An Assessment of Two Piston Bowl Concepts in a Medium-Duty Diesel Engine

    Kurtz, Eric M. / Styron, Joshua | SAE Technical Papers | 2012