Sökning: "lean-burn"

Visar resultat 21 - 25 av 29 avhandlingar innehållade ordet lean-burn.

1. 21. Deactivation mechanisms influencing the performance and durability of exhaust aftertreatment systems

   Författare :Jesus De Abreu Goes; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Thermal degradation; Gasoline particulate filters; Lean NOx traps; Sulfur poisoning.;

   Sammanfattning : As countermeasure to air pollution and global warming, more stringent environmental policy measures will probably come into force with the future emission standards, which will require important developments for gasoline and diesel vehicles to meet the emerging criteria. Efficient catalytic formulations and advanced strategies for exhaust aftertreatment systems will be therefore demanded to provide both high catalytic activity and stability, minimizing the environmental impact by automobiles. LÄS MER

3. 22. Fundamental Studies of Catalytic NOx Removal - Micro Kinetic Modelling, Monte Carlo Simulations and Flow Reactor Experiments

   Författare :Louise Olsson; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NO oxidation; Monte Carlo simulations; platinum oxide; kinetic modelling; NOx storage; barium oxide; environmental catalysis; NOx removal; platinum; flow reactor measurements;

   Sammanfattning : It is essential to decrease the CO2 emissions from vehicles, since CO2 is a greenhouse gas. One way to improve fuel economy and decrease CO2 emissions, is to run the engine with oxygen excess, so-called lean-burn operation. However, a major problem here is the reduction of the NOx in a lean atmosphere. LÄS MER

4. 23. On the role of Alkaline Earth Metal Oxides in Environmental Catalysis

   Författare :Peter Broqvist; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

   Sammanfattning : In heterogeneous catalysis, metal oxides have various roles: as catalysts, as support material for catalytically active metal particles, as promoters, as stabilizers, or as storage materials. Although their main application is as support material, their role as promoter or storage material becomes increasingly important as emission legislations are becoming more stringent. LÄS MER

5. 24. Variable Valve Actuation in a Spark Ignition Engine - A Flow Field and Heat Release Study

   Författare :Fredrik Söderberg; Förbränningsmotorer; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; framdrivningssystem; Gases; plasma; fluid dynamics; plasmas; Gaser; fluiddynamik; vakuumteknik; vibrationer; akustik; Motors and propulsion systems; Motorer; hydraulik; Maskinteknik; vibration and acoustic engineering; Laser Doppler Velocimetry Particle Image Velocimetry PIV LDV Wavelet Computational Fluid Dynamics CFD Variable Valve Actuation Timing Turbulence Combustion Engine Spark Ignition Miller; hydraulics; vacuum technology; Mechanical engineering;

   Sammanfattning : The objective of this thesis was to find ways of improving part-load efficiency for a spark ignition engine by studying the effects of variable-valve actuation on fluid flow and combustion. The in-cylinder flow was measured with laser doppler velocimetry, LDV, and particle image velocimetry, PIV. LÄS MER

7. 25. Diluted Operation of a Heavy-Duty Natural-gas Engine

   Författare :Mehrzad Kaiadi; Förbränningsmotorer; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

   Sammanfattning : Fuel economy and emissions are the two central parameters in heavy duty engines; most of the existing heavy duty engines are run with diesel. The overall efficiency of diesel engines is good however they suffer from high levels of emissions mainly NOX and soot. LÄS MER