This article reviews systematic research on combustion instabilities (principally rare, random misfires and partial burns) in spray-guided stratified-charge (SGSC) engines operated at part load with highly stratified fuel -air -residual mixtures. Results from high-speed optical imaging diagnostics and numerical simulation provide a conceptual framework and quantify the sensitivity of ignition and flame propagation to strong, cyclically varying temporal and spatial gradients in the flow field and in the fuel -air -residual distribution. For SGSC engines using multi-hole injectors, spark stretching and locally rich ignition are beneficial. Combustion instability is dominated by convective flow fluctuations that impede motion of the spark or flame kernel toward the bulk of the fuel, coupled with low flame speeds due to locally lean mixtures surrounding the kernel. In SGSC engines using outwardly opening piezo-electric injectors, ignition and early flame growth are strongly influenced by the spray's characteristic recirculation vortex. For both injection systems, the spray and the intake/compression-generated flow field influence each other. Factors underlying the benefits of multi-pulse injection are identified. Unresolved questions include (1) the extent to which piezo-SGSC misfires are caused by failure to form a flame kernel rather than by flame-kernel extinction (as in multi-hole SGSC engines); (2) the relative contributions of partially premixed flame propagation and mixing-controlled combustion under the exceptionally late-injection conditions that permit SGSC operation on E85-like fuels with very low NOx and soot emissions; and (3) the effects of flow-field variability on later combustion, where fuel-air-residual mixing within the piston bowl becomes important.


    Zugriff

    Zugriff über TIB

    Verfügbarkeit in meiner Bibliothek prüfen

    Bestellung bei Subito €


    Exportieren, teilen und zitieren



    Titel :

    Invited Review: Combustion instability in spray-guided stratified-charge engines: A review



    Erschienen in:

    Erscheinungsdatum :

    2015




    Medientyp :

    Aufsatz (Zeitschrift)


    Format :

    Print


    Sprache :

    Englisch



    Klassifikation :

    BKL:    52.35 / 52.35 Kolbenkraftmaschinen



    Combustion instability in spray-guided stratified-charge engines: a review

    Fansler,T.D. / Reuss,D.L. / Sick,V. et al. | Kraftfahrwesen | 2015



    Ignition Systems for Spray-Guided Stratified Combustion

    Wolf, Edgard / Weyand, Peter / Heise, Volker et al. | SAE Technical Papers | 2010


    Ignition systems for spray-guided stratified combustion

    Piock,W.F. / Weyand,P. / Wolf,E. et al. | Kraftfahrwesen | 2010


    Stratified charge engines

    Haslett,R.A. / Monaghan,M.L. / McFadden,J.J. et al. | Kraftfahrwesen | 1976