National Transport Library Research Database

Mätning, modellering och optimering av transienta och stationära partilkelemissioner från dieselmotorer (Measurements, modeling, and optimization of transient and stationary particle emissions from diesel engines)

  • Grant, Ann
  • AB Volvo, Svenskt företag eller organisation, 556012-5790
Sponsors, duration, budget: Vägverket ; 2006-10-01 -- 2009-11-30 ; 3500000 kronorRegistration number:
  • Vägverket AL90 A 2008:70786
Subject(s): Notes: Resultatsammanfattning: The formation and transformation from source to sink of particulate matter from different diesel engines and aftertreatment systems was measured during this project. Using a state-of-the–art PM instrument, particle size distribution or the number of particles of a given size was measured at different places along the exhaust system from engine out, after the diesel oxidation catalyst, after the diesel particle trap (sink), and after a urea SCR system. Additionally, insights into the fundamental mechanisms behind soot oxidation as a function of structure and oxygen binding site were modeled with microkinetic modeling. The degree of disorder of the graphitic particles creating edge sites for the binding of oxygen atoms appears to be the controlling factor for the initial rate of soot oxidation. Our measurements have shown that there is very little change in the particle size distribution along the exhaust line, except, of course, when they are trapped in a diesel particulate filter. The primary factor controlling the particle size distribution of emitted particles is how the engine is operated. It is the degree of mixing of the fuel and air (or lambda), the balance between soot formation and oxidation, which controls the mass of soot emitted. It appears that this balance of mixing also controls the size and number (or particle size distribution) of the emitted particles both from the engine and the aftertreatment system. The majority of the number and mass of particles are emitted during transients. There is a rapid and temporary increase in the count median diameter of the engine out particles during transients. With an exhaust gas recirculating (EGR) engine, the NOx level is the major controlling factor for both particle size and number whereas injection timing appears to be the major controlling factor in a non-EGR engine. The size and distribution of polyaromatic hydrocarbons, with a small number of measurements, is also controlled by the amount of EGR (or NOx level) and by the injection timing, primarily.Abstract: Partikelemissioner från dieselmotorer är ett stort hälsoproblem, särskilt i stadsmiljöer. Traditionellt har partikelmätningar i första hand genomförts under stationära betingelser, eller genom att mäta de integrerade emissionerna över en körcykel. Projektet syftar till detaljerad kunskap om de transienta betingelser som styr partikelemissionerna från motorn, och hur partiklarna transient omvandlas och insamlas i t.ex. partikelfilter. Modern partikelanalysutrustning med möjlighet att transient mäta antal partiklar, storleksfördelning och massan av partiklarna kommer att användas inom projektet. Parallellt med de transienta mätningarna kommer kemiska analyser av partiklarnas sammansättning att göras.Abstract: Particle emissions from diesel engines are a serious health issue, especially in urban environments. Particle measurements has mostly been performed at stationary conditions, or by measuring the total amount emitted during a test cycle. The goal of the project is to get a detailed understanding of how the transient conditions in the engine affect the particle emissions, and how the emitted particles in the exhaust line are transformed and collected in i.e. a particulate filter. State-of-the-art analysis equipment will be used for the transient measurements of number of particles, particle size distribution and particle mass. Chemical analysis of the particle composition will be performed in parallel with the transient measurements.
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