Soot Particle Size Distributions in Diesel Engines - Detailed Kinetic Modelling and Experimental Investigations
P. Priesching, AVL List GmbH, Graz, Austria
F. Mauss, Lund University, Lund, Sweden
W. Bauer, MAN AG, Nürnberg, Germany
M. Schmid, LTT, Nürnberg, Germany
The Diesel engine is known to be the most efficient power source for transportation today. The high efficiency leads to low green house gas emission and there is still the potential to increase fuel efficiency of Diesel engines with the corresponding further reduction of CO2 emissions. The improvements of the recent years, not only in the respect of economical and ecological characteristics, but also in respect of drivability and comfort, made Diesel engine powered cars more and more popular especially in Europe. Therefore special care has to be taken of the specific emission problems of the Diesel engine.
The ongoing discussion on the health risk related to soot particle emissions from high speed and commercial Diesel engines is a great challenge to engine manufacturers world-wide. Increases in engine efficiency have to be achieved in face of increasingly more stringent legislation on soot emissions and particle sizes.
However, the most important issue of diesel soot emissions is neither the total number density, nor the total mass. The most important issue is the toxicology of soot particles. The size of the particles, the particle surface properties and the shape of the particles determine the toxic levels of soot. The size of the particles determines how deep a particle may enter a human lung. The surface properties and the shape determine if the particle can cause chemical activity.
The intention of the presented work was to develop a new simulation tool that fits into a CFD workflow and provides information about the soot particle size distribution. Additionally it was necessary to improve and use state of the art measurement techniques in order to be able gain more knowledge about the behaviour of the soot particles and to validate the archived simulation results.