An experimental and theoretical investigation to minimise the hydrocarbon emissions from a 25 cm3 two-stroke engine with finger transfer ports is described. Finger ports have the side of each passage closest to the cylinder axis open to the cylinder bore making it possible to produce high-pressure die castings with the simplest of dies. Cylinders utilising this type of porting are believed to have inferior scavenging characteristics compared to those using closed or cup-handle porting.The effects of cylinder scavenging characteristics and port optimisation on engine performance were examined using a computer simulation. It is concluded that there is potential for a 70% reduction in exhaust hydrocarbon emissions through scavenging efficiency improvements and port optimisation, provided the cylinder scavenging can be developed to match that of the best existing unconventional crossflow scavenged designs.Stereolithography models of loop and cross-scavenged cylinders, all with finger ports, were evaluated using the QUB single-cycle gas testing apparatus to determine their idealised constant volume scavenging behaviour. The results from these tests are presented in the form of constant volume scavenging and trapping efficiency characteristics. The best crossflow designs are found to be superior to the loop-scavenged designs.A 38% reduction in brake specific hydrocarbon emissions is predicted for a projected crossflow design employing the best scavenging characteristic achieved with finger type transfer passages in this study.


    Zugriff

    Zugriff prüfen

    Verfügbarkeit in meiner Bibliothek prüfen

    Bestellung bei Subito €


    Exportieren, teilen und zitieren



    Titel :

    Reducing Exhaust Hydrocarbon Emissions from a Small Low Cost Two-Stroke Engine


    Weitere Titelangaben:

    Sae Technical Papers


    Beteiligte:
    Thornhill, D. J. (Autor:in) / Cunningham, G. (Autor:in) / Blair, G. P. (Autor:in) / Kenny, R. G. (Autor:in)

    Kongress:

    International Off-Highway & Powerplant Congress & Exposition ; 1998



    Erscheinungsdatum :

    14.09.1998




    Medientyp :

    Aufsatz (Konferenz)


    Format :

    Print


    Sprache :

    Englisch




    Reducing exhaust hydrocarbon emissions from a small low cost two-stroke engine

    Kenny,R.G. / Thronhill,D.J. / Cunningham,G. et al. | Kraftfahrwesen | 1998


    Two-stroke cycle engine exhaust emissions

    Kenny,R.G. / Queens Univ.of Belfast,GB | Kraftfahrwesen | 1991


    REDUCING EXHAUST EMISSIONS AND INCREASING POWER OUTPUT USING A TUNED EXHAUST PIPE ON A TWO-STROKE ENGINE

    Jonsson, B. I. R. / Blair, G. P. / Gustafsson, R. U. K. | SAE Technical Papers | 2001



    Developments in two-stroke cycle engine exhaust emissions

    Kenny,R.G. / Queens Univ.of Belfast,Dep.of Mechanical Engineering,GB | Kraftfahrwesen | 1992