Hydrogen assisted diesel combustion was investigated on a DDC ((Detroit Diesel Corporation)/VM Motori 2.5 l, 4-cylinder, turbocharged, common rail, direct injection light-duty diesel engine, with a focus on exhaust emissions. Hydrogen was substituted for diesel fuel on an energy basis of 0 %, 2.5 %, 5 %, 7.5 %, 10 % and 15 % by aspiration of hydrogen into the engine's intake air. Four speed and load conditions were investigated (1800 rpm at 25 % and 75 % of maximum output and 3600 rpm at 25 % and 75 % of maximum output). A significant retarding of injection timing by the engine's ECU (electronic control unit) was observed during the increased aspiration of hydrogen. The retarding of injection timing resulted in significant NO(x) emission reductions, however, the same emission reductions were achieved without aspirated hydrogen by manually retarding the injection timing. Subsequently, hydrogen assisted diesel combustion was examined, with the pilot and main injection timings locked, to study the effects caused directly by hydrogen addition. Hydrogen assisted diesel combustion resulted in a modest increase of NO(x) emissions and a shift in NO/NO2 ratio in which NO emissions decreased and NO2 emissions increased, with NO2 becoming the dominant NO(x) component in some combustion modes. CFD (omputational fluid dynamics) analysis of the hydrogen assisted diesel combustion process captured this trend and reproduced the experimentally observed trends of hydrogen's effect on the composition of NO(x) for some operating conditions. A model that explicitly accounts for turbulence-chemistry interactions using a transported PDF (probability density function) method was better able to reproduce the experimental trends, compared to a model that ignores the influence of turbulent fluctuations on mean chemical production rates, although the importance of the fluctuations is not as strong as has been reported in some other recent modelling studies. The CFD results confirm that temperature changes alone are not sufficient to explain the observed reduction in NO and increase in NO2 with increasing H2. The CFD results are consistent with the hypothesis that in-cylinder HO2 levels increase with increasing hydrogen, and that the increase in HO2 enhances the conversion of NO to NO2. Increased aspiration of hydrogen resulted in PM (particulate matter), and HC (hydrocarbon) emissions which were combustion mode dependent. Predominantly, CO and CO2 decreased with the increase of hydrogen. The aspiration of hydrogen into the engine modestly decreased fuel economy due to reduced volumetric efficiency from the displacement of air in the cylinder by hydrogen.


    Zugriff

    Zugriff über TIB

    Verfügbarkeit in meiner Bibliothek prüfen

    Bestellung bei Subito €


    Exportieren, teilen und zitieren



    Titel :

    Hydrogen assisted diesel combustion


    Beteiligte:

    Erschienen in:

    Erscheinungsdatum :

    2010


    Format / Umfang :

    17 Seiten, 31 Bilder, 3 Tabellen, 42 Quellen




    Medientyp :

    Aufsatz (Zeitschrift)


    Format :

    Print


    Sprache :

    Englisch




    Hydrogen Enriched Diesel Combustion

    McCormick, Gregory / Samuel, Stephen | SAE Technical Papers | 2010


    Hydrogen combustion under diesel engine conditions

    Naber, J.D. / Siebers, D.L. | Tema Archiv | 1996


    A study on hydrogen-fueled diesel combustion

    Ikegami, M. / Miwa, K. / Shioji, M. et al. | Tema Archiv | 1980


    Modified Heat Release Analysis for Diesel-Assisted CNG Combustion

    Langness, Chenaniah / Depcik, Christopher / Mattson, Jonathan M. S. | SAE Technical Papers | 2015


    Modified Heat Release Analysis for Diesel-Assisted CNG Combustion

    Mattson, Jonathan M. S. / Langness, Chenaniah / Depcik, Christopher | British Library Conference Proceedings | 2015