Variable-valve-timing technology and ethanol addition to gasoline are both considered to be effective strategies for better performance and potential improvement in the fuel economy in gasoline engines. In this study, a Jaguar V8, naturally aspirated spray-guided direct-injection engine was operated with four different valve-timing combinations using an unleaded gasoline and a gasoline–10 vol % ethanol blend. The internal exhaust gas recirculation rate and the in-cylinder gas temperature were modelled for different valve-timing strategies. The results showed that a high valve overlap led to high internal exhaust gas recirculation and a high charge temperature, which evidently improved the fuel spray atomization and reduced the particulate matter emissions. Adding 10 vol % ethanol led to a rise in the total particle number and the total particle mass in emissions by a factor of up to 2 under warm-engine conditions (with a coolant temperature of 90 °C) but led to a reduction in the total particle number and the total particle mass in emissions by up to two-thirds under cold conditions (with a coolant temperature of 20 °C). Thermogravimetric analysis tests were conducted to analyse the compositions of filter-borne particulate matter emissions, and more than 75 mass % organic material was always present. All measurements are reported for both pre- and post-three-way-catalyst samples, the latter always showing a significant reduction (a factor of about 2) in the particulate matter emissions.


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    Titel :

    Effect of the valve timing and the coolant temperature on particulate emissions from a gasoline direct-injection engine fuelled with gasoline and with a gasoline–ethanol blend


    Beteiligte:
    Chen, Longfei (Autor:in) / Stone, Richard (Autor:in) / Richardson, Dave (Autor:in)


    Erscheinungsdatum :

    01.10.2012


    Format / Umfang :

    12 pages




    Medientyp :

    Aufsatz (Zeitschrift)


    Format :

    Elektronische Ressource


    Sprache :

    Unbekannt