• Journal of the Korean Society for Precision Engineering
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• v.27 no.7
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• pp.101-108
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• 2010

Domestic three-way catalyst satisfies exhaust gas conversion efficiency or pressure drop etc. but doesn't satisfy thermal durability. Thermal stress analysis for three-way catalyst was performed based on experimental temperature distribution. Thermal safety of three-way catalyst was estimated by safety factor. Aspect ratio variable had the most significant effect on thermal stress. Thickness variable had the least significant effect on thermal stress. Optimal conditions for premature failure prevention of three-way catalyst were as follows : (1) aspect ratio of three-way catalyst : 0.6:1 (2) 2.84mm thick (3) silicon nitride. The safety of Taguchi-optimized three-way catalyst were 4.7 times higher than that of existent three-way catalyst.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.9
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• pp.58-66
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• 2010

This study examines thermal safety on three-way catalyst that dominates 70 % among whole exhaust gas purification device in 2003. Three-way catalyst durability in the Korea requires 5 years/80,000 km in 1988 but require 10 years/120,000 km after 2002. Three-way catalyst durability in the USA requires 7 years/120,000 km but require 10 years/160,000 km after 2004. Three-way catalyst maintains high temperature in interior domain but maintains low temperature on outside surface. Therefore this device shows tensile stress on outside surface. Temperature distribution of three-way catalyst was acquired by thermal flow analysis for predicted thermal flow parameter. Thermal stress analysis for three-way catalysis was performed based on this temperature distribution. Thermal safety of three-way catalyst was estimated by power law dynamic fatigue life estimation and strength reduction methods for thermal stress.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.1
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• pp.13-19
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• 2013

This study examines thermal safety on three-way catalyst that dominates 70% among whole exhaust gas purification device in 2003. Three-way catalyst maintains high temperature in interior domain but maintains low temperature on outside surface. Therefore this device shows tensile stress on outside surface. Temperature distribution of three-way catalyst was acquired by thermal flow analysis for predicted thermal flow parameter. Thermal stress analysis for three-way catalysis was performed based on this temperature distribution. Thermal safety of three-way catalyst was estimated by strength reduction factor and failure probability.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.6
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• pp.669-676
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• 2014

A three-way catalyst substrate for domestic passenger car satisfies the design criteria for exhaust gas exchange and pressure drop but does not have satisfactory thermal fatigue performance. Prefracture faults in this three-way catalyst substrate has often been discovered in vehicle repair or vehicle inspection facilities. This paper presents a thermal fatigue performance estimation method for a three-way catalyst substrate using a probabilistic strength reduction factor model. This method is superior to the thermal fatigue performance estimation method for a three-way catalyst substrate that uses a deterministic strength model.

• Journal of Institute of Convergence Technology
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• v.1 no.1
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• pp.13-17
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• 2011

The car industry is one of the technological applications which more rare earth metals employes as three-way catalysts. Therefore, the recovery of rare earth metals from the used automotive three-way catalysts could be important source to obtain these metals. This work presents the analysis of market and demand for rare earth metal in automotive three-way catalyst and introduces the dry and the wet processes for the recovery of rare earth metals from used three-way catalyst. Finally, the alternative methods to conventional wet processes was simply suggested based on the economic and ecological point of view.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.9
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• pp.3125-3134
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• 2010

Three-way catalyst durability in the Korea requires 5 years/80,000km in 1988 but require 10 years/120,000km after 2002. Domestic three-way catalyst satisfies exhaust gas conversion efficiency or pressure drop etc. but don't satisfy thermal durability. Three-way catalyst maintains high temperature in interior domain but maintain low temperature on outside surface. This study evaluated thermal durability of three-way catalyst by thermal flow and structure analysis and the procedure is as followings. Thermal flow parameters ranges were determined by vehicle test and basic thermal flow analysis. Response surface for rear catalyst temperature was constructed using the design of experiment (DOE) for thermal flow parameters. Thermal flow parameters for rear catalyst temperature in vehicles examination were predicted by desirability function. Temperature distribution of three-way catalyst was estimated by thermal flow analysis for predicted thermal flow parameters.

• Journal of Advanced Marine Engineering and Technology
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• v.23 no.3
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• pp.389-397
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• 1999

Recently the use of Pd catalyst have been continued to expand because of cost avaliabilityand performance advantages. Especially the Pd+Rh catalyst instead of the Pt+Rh catalyst had been used for most of three way catalysts because of the more stringent emission standards and its higher temperature effectiveness. The main purpose of this study is to investigate the design parameter impacts on the Pd+Rh cat-alyst for the automotive exhaust catalysts application. This study was investigated on the catalyst efficiency for the volume and the precious metal loading of the Pd+Rh ceramic monolithic cata-lyst. And experiments concerning the effects of volume and precious metal loading on Pd+Rh three way catalysts were conducted to examined the catalyst light-off temperature and conver-sion efficiency on higher volume demonstrated almost similar performance. But their effects on higher precious metal loading demonstrated considerably better performance.

• Journal of ILASS-Korea
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• v.28 no.3
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• pp.150-155
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• 2023

Cold-start emissions are given great importance under the Euro-7 emission standard due to their significant impact on overall vehicle emissions. When an engine is started from a cold state, the combustion process is not yet optimized, leading to higher emissions. Hybrid vehicles, in particular, may face additional challenges, as their engine may remain inactive for extended periods, causing their catalysts to cool down and potentially become less effective in reducing emissions. In the present study, the performance of an electric heater was investigated as a means to enhance the catalyst heating during the start-up time. A simulation tool was utilized to develop a model for the gasoline exhaust aftertreatment system. The result indicates that the heater was able to increase the three-way catalyst temperature to 500℃ in 4 s using 20 kW power. In addition, the implementation of a secondary air supply resulted in reduced temperature overshoot and improved conversion efficiencies.

• Applied Chemistry for Engineering
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• v.20 no.4
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• pp.430-436
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• 2009

Deactivated three-way catalysts which had been exposed to gasoline engine exhaust for a long time were remanufactured by ultra sonic cleaning with distilled water, sulfuric acid solution and impregnation with precious metals (Pt, Pd, Rh). The catalytic properties as well as conversion reactivity of CO, THC and NOx about fresh, aged and remanufactured catalysts were examined. Most of the pollutants deposited on the aged three-way catalysts were removed in the remanufacturing process of those catalysts. At the same time a little amount of precious metals like Pt and Pd were removed in the remanufacturing process. Under the experimental condition used in this study, in the case of the remanufactured catalysts with impregnation of precious metals, the catalytic activities were recovered to almost the same level, or higher level of that of the fresh catalyst.

• Journal of ILASS-Korea
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• v.21 no.3
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• pp.137-143
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• 2016

The LPG vehicles are being operated by commercial purposes generally such as taxis. Most of taxis have a long-mileage and a harsh driving pattern. These properties may accelerate aging of the three-way catalysts much faster than the passenger vehicles. Because of this background, it was analyzed the test result of fuel efficiency and emissions on the LPG-fueled light duty vehicle. It was selected for a LPG vehicle of ULEV level to measure the fuel efficiency and emissions of the aged three-way catalysts. And the aged three-way catalysts which was driven about 300,000km and 550,000km replaced on the test vehicle in consecutive order. As a result, The aged three-way catalysts generally had no effect on fuel efficiency result, and harmful exhaust emissions had been shown to increase in most of the test mode, even though it satisfied the regulation value on most test modes.