In a Technology Foundation STW project, Coen van Gulijk has developed a new concept for a robust soot filter for diesel engines. As well as filter stages, the filter has an open canal so as to exclude the danger of blockage and thus fire.
The new soot filter consists of series of perforated ceramic foams. The surface of the ceramic is impregnated with a catalyst on which the incoming soot particles are burnt and released as gases. Ash particles from impurities in the diesel, which enter the filter with the soot, remain in the pores of the ceramic foam plates. The ceramic foam can absorb a large quantity of ash before it risks becoming blocked and can therefore be used for a long time. The filter is highly suitable for removing soot from so-called heavy diesel oil. Heavy diesel oil is a heavy fuel containing many minerals and metals which produce ash. Existing filter systems would become blocked if used with heavy diesel oil.
As the filter is built from separate filter plates instead of a single block, it is almost indestructible. Even if all of the plates were to break, the filter function remains intact. An inbuilt open canal prevents the filter from becoming blocked. However, a disadvantage of the design is that it requires a lot of space. This means it is not suitable for cars but it can be used for ships, which often use heavy diesel oil, as equally fixed motors or trains.
The design of the new filter is partly based on studies concerning the form and size of soot particles. Diesel particles have a structure which consists of branched lumps of soot chains. Research has shown that due to this fractal structure, diesel particles are in fact up to ten times bigger than is indicated with measuring instruments. This was established with the aid of an electron microscope. Accordingly the behaviour of the soot particles relevant to the filtering is different than was thought; they diffuse more slowly but are more likely to stick to the filter.
Michel Philippens | alfa
New technology for ultra-smooth polymer films
28.06.2018 | Fraunhofer-Institut für Organische Elektronik, Elektronenstrahl- und Plasmatechnik FEP
Diamond watch components
18.06.2018 | Schweizerischer Nationalfonds SNF
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
19.07.2018 | Earth Sciences
19.07.2018 | Power and Electrical Engineering
19.07.2018 | Materials Sciences