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SETSCI - Volume (2018) ISAS 2018 - Ist International Symposium on Innovative Approaches in Scientific Studies, Kemer-Antalya, Turkey, Apr 11, 2018 Particulate Filters for Internal Combustion Engines (ISAS 2018_140)
Nurcan Çalış Açıkbaş 1, Gökhan Açıkbaş 2, Selçuk Özcan 3, Şeref Soylu 4 * 1Metallurgy and Materials Engineering Department, Bilecik Seyh Edebali University , Bilecik, Turkey 2Bilecik Şeyh Edebali Üniversitesi, Meslek Yüksekokulu, Metalürji Programı , Bilecik, Turkey 3Chemical Engineering Department, Bilecik Seyh Edebali University , Bilecik, Turkey 4Department of Mechanical Engineering, Bilecik S. Edebali University , Bilecik, Turkey * Corresponding author: email@example.com Published Date: 2018-06-23 | Page (s): 151-152 | 82 4
Increasing number of motor vehicles together with economic development brings serious air pollution problems. Especially, Particle Matter emissions from Internal Combustion Engines are difficult to control and highly dangerous for human health. Both Europa and USA have been regulating the emissions from motor vehicles for a long time, but air pollution is still a major concern for human health due to increasing number of motor vehicles. Today, Particle Filters (PFs) are the most effective technology to minimize PM emissions from motor vehicles and a Diesel Particle Filter is one of the most important parts of a diesel after-treatment system. In addition, it is expected that even gasoline engines, especially those with direct injection systems, will be equipped with Gasoline Particle Filters (GPFs) due to the future update of the relevant regulations. Because of their porous structure PFs can easily filter exhaust gas and accumulate PMs in the PF just like a tea filter, which is used commonly in kitchens. Once the accumulated PMs reach a critical level inside the PF, which may cause increasing back pressure for the engine, they must be burn out and emitted to atmosphere in gaseous form; which is called Regeneration process. This process is highly important as it sets limits to thermal and mechanical properties of a PF.
General characteristics of materials to be used as DPF; low thermal expansion coefficient (1,0 - 1,5x10-6 / oC, ~ 800oC), high temperature stability (~ 1400oC), corrosion resistance, sufficient mechanical strength (> 12 MPa) good thermal conductivity to reduce the effect of thermal stresses and low density to reduce fuel consumption. Good corrosion and oxidation resistance is required against sulfur-containing exhaust gas components. Most importantly, it should have over 90% filtration capability. Nowadays ceramics are popular as the filtering material that can meet these properties. The commercial DPFs currently used are Cordierite, SiC, Mullit, Al-Titanate and FeCrNi alloy. Cordierite is Mg-Al silicate phase and this is produced from natural raw materials such as kaolin and talc, so it is very economical and it is the most commonly used substrate material. Other advantages include; it has low density and therefore is light, due to low thermal expansion coefficient minimum thermal stresses reveal, low sintering temperature and hence easy production procedures and so no need for a special furnace atmosphere. On the other hand, low thermal conductivity creates a problem during regeneration and in some regions of the DPF the temperature can reach the melting temperature of cordierite. The other substrate material is SiC. SiC is at the forefront with its high thermal conductivity, elastic modulus, and service temperature and corrosion resistance. Mullite has a coefficient of thermal expansion similar to that of SiC. It has high strength and high temperature resistance. It is sintered without special atmospheric conditions by using economical raw materials. It is very economical in this respect. The other material is Al-titanate. Its leading feature is its excellent thermal shock resistance due to its low thermal expansion coefficient. But the elastic modulus and mechanical strength are poor. The metal filters have a similar coefficient of thermal expansion to that of the external components and are therefore easy to install. The main disadvantage of sintered metal filters is that they are expensive due to the high cost of the starting metal powders and the complicated welding process and high density. When we evaluate the properties required from DPFs, SiC substrates are at the forefront in terms of performance.
particle filter, environmental pollution, internal combustion engines, Ceramic, SiC