• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.5
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• pp.3035-3043
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• 2015

This study evaluates the thermal structural safety of the three-way catalyst(TWC) substrate for domestic passenger cars. Thermal-fluid boundary conditions on the TWC substrate were determined by D-optimal DOE. The thermal stresses on the TWC substrate were calculated by the temperature distribution obtained from the CFD results. The safety factors of the TWC substrate were determined by statistical strength and stress distributions and estimated to be 0.275. The thermal stresses for TWC substrate exceeded the strength of the material. Therefore, it is necessary to redesign the TWC substrate because it has much shorter service life than design life.

• 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 the Korea Academia-Industrial cooperation Society
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• v.14 no.12
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• pp.6106-6113
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• 2013

Automotive three-way catalyst substrate has a cordierite ceramic honeycomb structure. The substrate in the high engine speed range doesn't satisfy the design fatigue life due to the low mechanical properties of cordierite ceramic. SiC ceramic has higher mechanical properties than cordierite ceramic. If the automotive three-way catalyst substrate is made from the SiC ceramic honeycomb structure, the substrate can be prevented from premature failure. In this study, the mechanical properties of SiC ceramic honeycomb substrate were estimated by FEA. The FEA results indicated that the MOR and elastic modulus for the SiC ceramic honeycomb substrate was much higher than those for the cordierite ceramic honeycomb substrate.

• Proceedings of the KAIS Fall Conference
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• 2011.05b
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• pp.989-992
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• 2011

삼원 촉매는 주로 코제라이트 세라믹으로 제작되는 다공성 부품이다. 그러나 코제라이트 세라믹은 열적충격온도가 낮아 엔진의 혼합기가 농후한 경우 삼원촉매의 열적 내구성이 급격히 떨어져 내구 수명을 제대로 만족시키지 못하는 차량이 급격히 증가하고 있다. 따라서 본 논문은 유한요소법으로 구한 SiC 세라믹 재료의 등가 물성치를 기초로 SiC 세라믹 촉매 담체의 기계적 물성치를 유한요소해석용시험편으로 구한 뒤 SiC 세라믹 촉매담체가 실차에 설치될 경우의 열피로 성능에 대하여 평가하였다.

• 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.

• 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.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.2
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• pp.129-138
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• 2010

Technical ceramics, due to their unique physical properties, are excellent candidate materials for engineering applications involving extreme thermal and chemical environments. When ceramics are rapidly cooled, they receive thermal shock. The thermal shock parameter is defined as the critical temperature difference. The critical temperature difference for ceramic parts is influenced by its size, the convective heat transfer coefficient, etc. The thermal shock for a component is analyzed by using the transient thermal stress. If the transient thermal stress exceeds the modulus of rupture (MOR), cracking by thermal shock is initiated. The critical temperature difference for water is less than the critical temperature difference for air. The three-way catalyst substrate used in this study has an adequate performance against thermal shock because its radial and axial temperature differences existed below the critical temperature differences.