The NOx emissions during the crank-start and cold fast-idle phases of a GDI engine are analyzed in detail. The NOx emissions of the first 3 firing cycles are studied under a wide set of parameters including the mass of fuel injected, start of injection, and ignition timing. The results show a strong dependence of the NOx emissions with injection timing; they are significantly reduced as the mixture is stratified. The impact of different valve timings on crank-start NOx emissions was analyzed. Late intake and early exhaust timings show similar potential for NOx reduction; 26-30% lower than the baseline. The combined strategy, resulting in a large symmetric negative valve overlap, shows the greatest reduction; 59% lower than the baseline. The cold fast-idle NOx emissions were studied under different equivalence ratios, injection strategies, combustion phasing, and valve timings. Slightly lean air-fuel mixtures result in a significant reduction of NOx. The engine-out emissions are highly sensitivity to combustion phasing. Initial retard results in lower mass NOx emissions up to CA50 around 40 °CA aTDC-compression. After this point the increase in fuel consumption and the reduction on residual fraction reverse the trend leading to an increase in NOx mass emissions for later combustion phasing. Moderate exhaust timing advance is beneficial for NOx emissions and has no impact on the exhaust enthalpy flow.


    Zugriff

    Zugriff prüfen

    Verfügbarkeit in meiner Bibliothek prüfen

    Bestellung bei Subito €


    Exportieren, teilen und zitieren



    Titel :

    Analysis of NOx Emissions during Crank-Start and Cold Fast-Idle in a GDI Engine


    Weitere Titelangaben:

    Sae Int. J. Engines


    Beteiligte:

    Kongress:

    WCX™ 17: SAE World Congress Experience ; 2017


    Erschienen in:

    Erscheinungsdatum :

    2017-03-28


    Format / Umfang :

    10 pages




    Medientyp :

    Aufsatz (Konferenz)


    Format :

    Print


    Sprache :

    Englisch




    A Method to Reduce Cold Start Emissions while Shortening Fast Idle Catalyst Light-off Time

    Hollowell, Jeffrey / Ha, Kyoung-Pyo / Shirley, Mark et al. | SAE Technical Papers | 2023


    Cycle-by-Cycle Analysis of Cold Crank-Start in a GDI Engine

    Rodriguez, J. Felipe / Cheng, Wai K. | SAE Technical Papers | 2016


    Impact of Cold Ambient Conditions on Cold Start and Idle Emissions from Diesel Engines

    Liu, Dai / Xu, Hongming / Piaszyk, Jakub et al. | SAE Technical Papers | 2014


    IDLE AND COLD-START START ELIMINATION SYSTEM IN LOCOMOTIVES

    GOTMALM CHRISTER / MANCUSO JAMES | Europäisches Patentamt | 2017

    Freier Zugriff