Search for dissertations about: "Spark"

Showing result 11 - 15 of 139 swedish dissertations containing the word Spark.

  1. 11. An Experimental Study of a Spark-assisted

    Author : Andreas Berntsson; [2006]
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

    Abstract : Future requirements for reductions in fuel consumption and emissions from ground vehicles might be met by using the HCCI combustion concept, in which a more or less homogenous air fuel mixture is compressed to auto-ignition. This consumes less fuel than normal SI combustion and its ability to burn lean mixtures at low temperatures has a positive impact on exhaust emissions. READ MORE

  2. 12. Spark Plasma Sintering of Si3N4-based Ceramics Sintering mechanism-Tailoring microstructure-Evaluationg properties

    University dissertation from Stockholm : Institutionen för fysikalisk kemi, oorganisk kemi och strukturkemi

    Author : Hong Peng; Zhijian (James) Shen; Mats Nygren; Michael J. Hoffmann; [2004]
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; spark plasma sintering; silicon nitride ceramics; grain growth kinetic; superplasiticity; liqiud phase sintering; NATURAL SCIENCES Chemistry; NATURVETENSKAP Kemi;

    Abstract : Spark Plasma Sintering (SPS) is a promising rapid consolidation technique that allows a better understanding and manipulating of sintering kinetics and therefore makes it possible to obtain Si3N4-based ceramics with tailored microstructures, consisting of grains with either equiaxed or elongated morphology. The presence of an extra liquid phase is necessary for forming tough interlocking microstructures in Yb/Y-stabilised α-sialon by HP. READ MORE

  3. 13. Numerical Simulations of Long Spark and Lightning Attachment

    University dissertation from Uppsala : Acta Universitatis Upsaliensis

    Author : Liliana Arevalo; Vernon Cooray; Dan Windmar; [2011]
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; breakdown; discharge; leader channel; lightning attachment; negative discharge; positive discharge; streamer; TECHNOLOGY Electrical engineering; electronics and photonics Electrical engineering; TEKNIKVETENSKAP Elektroteknik; elektronik och fotonik Elektroteknik; Engineering Science with specialization in Atmospheric Discharges; Teknisk fysik med inriktning mot atmosfäriska urladdningar;

    Abstract : The research work presented here is concerned with numerical simulations of two different electrical phenomena: Long gap electrical discharges under switching impulses and the lightning attachment process associated with positive upward leaders. The development of positive upward leaders and the progression of discharges in long gaps are attributable to two intertwined physical phenomena, namely, the leader channel and the streamer zone. READ MORE

  4. 14. Modeling of Flame Propagation in Spark Ignition Engines

    University dissertation from Uppsala : Acta Universitatis Upsaliensis

    Author : Johan Wallesten; [2003]
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES;

    Abstract : Developers and manufacturers of gasoline engines are struggling to improve fuel economy and minimize negative environmental effects. Hence, lean burn and direct injection (DI), in particular stratified charge (SC), spark ignition (SI) engines are of special interest. READ MORE

  5. 15. Air charge estimation in turbocharged spark ignition engines

    University dissertation from Linköping : Linköpings universitet

    Author : Per Andersson; [2005]
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

    Abstract : Turbocharged (TC) spark-ignited (SI) engines are popular as they combine high power output with good fuel economy. Furthermore, their emissions can be successfully reduced using a three way catalyst (TWC) provided that the air-fuel ratio is precisely controlled. READ MORE