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The durability of a silicon carbide diesel particulate filter (SiC-DPF) is important because SiC-DPF are often utilized under severe operating conditions. This paper presents test results under long-term operation. The static, cyclic and dynamic fatigue properties of silicon-bonded SiC (Si-SiC) materials were investigated. Creep strain was not observed at normal operation temperature (600°C). Samples did not fracture in cyclic fatigue tests after more than 105 cycles at both 9MPa at 600°C and 2MPa at 1000°C. Furthermore, from dynamic fatigue testing, it is predicted that there would be no deterioration in strength in at 600°C, as well as at room temperature (RT) with respect to time.

The Diesel Particulate Filter (DPF) system has been developed as one of key technologies to comply with tight diesel PM emission regulations. For the DPF control system, it is necessary to maintain temperature inside the DPF below the allowable service temperature, especially during soot regeneration to prevent catalyst deterioration and cracks. Therefore, the evaluation of soot regeneration is one of the key development items for the DPF system. On the other hand, regeneration evaluation requires a lot of time and cost since many different regeneration conditions should be investigated in order to simulate actual driving. The simulation tool to predict soot regeneration behavior is a powerful tool to accelerate the development of DPF design and safe regeneration control strategies. This paper describes the soot regeneration model applied to fuel additive and catalyzed types, and shows good correlation with measured data.

Modern filter systems allow a significant reduction of diesel particulate emissions. The new silicon bonded silicon carbide particulate filters (Si-SiC filters) play an important role in this application, because they provide flexibility in terms of mean pore size and porosity and also have a high thermal shock capability to meet both engineering targets and emission limits for 2005 and beyond. Particulate filters are exposed to high temperatures and a harsh chemical environment in the exhaust gas of diesel vehicles. This paper will present further durability evaluation results of the new Si bonded SiC particulate filters which have been collected in engine bench tests and vehicle durability runs. The Si-SiC filters passed both 100 and 200 regeneration cycles under severe ageing conditions and without any problems. The used filters were subjected to a variety of analytical tests. The back pressure and ash distribution were determined. The filter material was also analysed.

The DPF(Diesel Particulate Filter) has been established as a key technology in reducing diesel PM emission. Also Catalyzed-DPF Systems are viewed as the next generation DPF System in the automotive sector, replacing the current Fuel Additive System. The performance requirements of the DPF-equipped vehicle are good fuel economy, good driving performance, high PM regeneration performance of accumulated soot and high durability. In this paper the effect of Catalyzed-DPF characteristics, such as porosity, pore size, cell structure and catalyst loading have been defined on pressure drop, filtration efficiency, regeneration efficiency and regeneration behavior.

DPFs (Diesel Particulate Filters) have been a primary technology utilized to purify diesel PM emissions. One of the major challenges of the DPF is to reduce pressure drop caused by PM and ash accumulation. This paper reports on the definition and investigative results of several major parameters which determine the pressure-drop of Cordierite and SiC (Silicon Carbide) DPF's. After which, the successful material development for low pressure-drop Cordierite and SiC DPF's are presented.

It is well known that an EHC (Electrically Heated Catalyst) is very effective in reducing cold start HC emissions. However, the large electric power consumption of the EHC is a major technical issue. When installed in the exhaust manifold, the EHC can take advantage of exhaust heat to warm up faster, resulting in a reduced electric power demand. Therefore, a structurally durable EHC which can withstand the severe manifold conditions is desirable. Through the use of a extruded monolithic metal substrate, with a flexible hexagonal cell structure and a special canning method, we have succeeded in developing a structurally durable EHC. This new EHC installed in the exhaust manifold with a light-off catalyst directly behind it demonstrated a drastic reduction in FTP (Federal Test Procedure) Total HC emissions.

The characteristics of DC butt welding of high strength hot rolled steel was studied in relation to the production of wheel rims. A thermal distribution analysis of DC butt welding indicated the importance of the optimization of welding condition as the maximum temperature attained in DC butt welding significantly differed from place to place along the welding line. Insufficient heat input or overheating might cause cold weld or solidification cracking. Particularly,the welding current and welding cycle should be strictly controlled in order to make a weld with good cold formability. The influence of steel chemistry on weld hardness was also investigated. High strength steel for DC butt rim welding should be produced with the least Ceq. because a relatively early stage bead trimming enhances hardenability of the weld,which increases sensitivity to cracking.