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RACK ROLLING을 고려한 R/P GEAR SYSTEM 설계
한현식(Hyunsik Han),손명섭(Myungseob Son),허성무(Sean Heo) 한국자동차공학회 2020 한국자동차공학회 학술대회 및 전시회 Vol.2020 No.11
The change in energy paradigm according to global eco-friendly policies is accelerating popularization of electric vehicles, and as the time of sharing economy and autonomous car is coming, steering system is also facing new challenges. As part of that, in order to cope with increase in the weight of electric vehicles and rapid increase in mileage of autonomous vehicles, each supplier need to ensure reliability of their R/P Gear system(DP-EPS, SbW, MRP) under more severe conditions. In this paper, in order to improve the reliability of the rack(or pinion) tooth, which are the main parts of the system, a factor called ‘Stress factor’, which is independent from the contact ratio and another factors that have been used traditionally, is introduced to examine stress concentration phenomenon which is occurred on tooth by ‘Rack rolling’. The factor is validated by comparing it with our past test history, and furthermore, a review tool is created using excel so that engineers can use it easily. By confirming the durability of the gear in advance through this paper, reliable data can be presented when trying to receive contracts, and time and cost can be reduced by preventing design changes related to tooth failure that may occur during the development process.
한현식(Hyunsik Han),송진우(Jinwoo Song) 한국자동차공학회 2005 한국자동차공학회 춘 추계 학술대회 논문집 Vol.2005 No.5_1
Three-way catalysts (TWC) have been contributing to cleaning the harmful automotive emissions such as HC, CO and Nox. OSC has been regarded as the most important component in the modern TWC because it keeps the air-to-fuel ratio relatively constant at catalyst bed around the stoichiometric point in spite of highly transient real driving condition. This allows the oxidative and reductive reactions to occur simultaneously at same catalyst. The evolution of OSC has been leading the progress of modern TWC that requires high catalytic performance for more than 100,000 miles. OSC is important in both aspects of oxygen-buffer at the catalyst and promoter through the synergistic interaction with precious metals. Even though pure cerium oxide was the first component that had been commercially used, the poor thermal stability was a weak point. Composite material, such as CeO₂-ZrO₂, with higher thermal stability than pure cerium oxide has been explored to comply with ever tightening emission regulations. In this paper, the characteristics of the advanced oxygen storage component, obtained by the various characterization tools, as well as TWC using the material, obtained at engine and vehicle test benches, will be shown.
한재욱(Jaeuk Han),김진원(Jinwon Kim),김동현(Donghyun Kim),김은석(Eunseok Kim),한현식(Hyunsik Han) 한국자동차공학회 2014 한국자동차공학회 부문종합 학술대회 Vol.2014 No.5
V2O5 catalysts were major urea-SCR catalysts previously, but zeolite catalysts have also been considered in order to meet more stringent emission regulations. V2O5 catalysts have higher resistance to sulfur compounds which were originated from diesel fuel and engine oil, but show lower thermal durability and earlier NH3 slip compared to zeolites due to their lower NH3 storage capacity at transient driving conditions repeating rapid accelerations and decelerations. Zeolites have larger NH3 storage capacity, better deNOx activity at low temperature and higher thermal durability, but lower sulfur durability compared with V2O5 catalysts. In this study, we considered new catalyst concept by combination of V2O5 catalysts and zeolites in order to take advantages of V2O5 catalyst and zeolite, so we could develop new SCR catalyst via optimization of washcoat architecture and loading. We confirmed this catalyst showed better NH3 storage compared with V2O5 catalyst at transient conditions and better sulfur durability compared with zeolites by several rig and engine tests.
연태헌(Taehun Yeon),한현식(Hyunsik Han) 한국자동차공학회 2007 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
In order to meet the stringent emissions regulations, new aftertreatment technologies such as EHC, secondary air injection, spark retardation and HC Trap for reducing the cold start emission have been proposed, and some of them have already been incorporated into production, to address these issues. This paper introduces the new technology which can significantly lower cold-start emission from gasoline vehicle by supplying air into the catalyst inlet. right after the engine shut-down. Modeling strongly indicates that might be associated with oxygen stored in the catalyst by the air injection.
[가솔린엔진부문] 촉매 변환기의 냉시동 성능 평가 방법 : Fast Light-off Test
연태헌(Taechun Yeon),강희천(Heecheon Kang),한현식(Hyunsik Han) 한국자동차공학회 2000 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
Most of THC emission during FTP test comes from the cold-start phase. Increasing the cell density of honeycomb substrate and precious metal loading has been considered as effective way to reduce the cold-start emission. This paper describes the new evaluation method. fast light-off test, which can be effectively applied for the cold-start performance of catalytic converter. It was found that fast LOT method could be an effective way to investigate the characteristics of catalytic converter including catalyst itself
작동 온도 영역이 확장된 제올라이트계 SCR 촉매 개발
김진원(Jinwon Kim),한재욱(Jaeuk Han),임윤택(Yuntaek Lim),김은석(Eunseok Kim),한현식(Hyunsik Han) 한국자동차공학회 2014 한국자동차공학회 부문종합 학술대회 Vol.2014 No.5
Selective catalytic reduction of NOx by NH₃(NH₃-SCR) is widely applied in the treatment of NOx emissions form diesel vehicles. Zeolite-based SCR catalysts have been widely studied and used for NH3-SCR due to the high NO conversions that can be obtained in relatively wide temperature windows. This paper had been conducted to investigate the NOx reduction activity of SCR using combination of catalyst. Temperature range of catalytic activity has been changed with changing Cu status in Cu-ion exchange catalyst. Fe-ion exchange catalyst that showed good activity at high temperature. Two kinds of catalyst had combined for increasing catalytic activity at whole range. In case of Cu-C & Fe-C combination catalysts, Fe-C catalyst at front position and Cu-C at rear position system showed good activity at whole range. The best activity showed at Fe/Cu-A and Fe/Cu-B. Considering N2O formation, Cu & Fe combination catalyst had showed better performance than Cu only catalyst.
하재어(Jaeau Ha),송진우(Jinwoo Song),한현식(Hyunsik Han) 한국자동차공학회 2006 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
H₂S suppression three-way catalyst technology has been developed for gasoline powered vehicles. H₂S, which causes the rotten egg odor, is formed on three-way catalyst during fuel rich operation cycles from the sulfur stored at CeO₂ and Al₂O₃ during fuel lean excursion. Since 1970s, NiO has been used widely as H₂S scavenger. However, NiO has given rise to concern about its harmfulness in especially Europe and Korea. Through the numerous fundamental studies using powder material, we identified a solid acid material as harmless substitute for NiO, for H₂S suppression. The solid acid containing three-way catalyst showed much better H₂S suppression and better catalytic performance to remove the pollutants than NiO containing catalyst.
[가솔린엔진부문] Pd-Only 삼원 촉매 개발 : 촉매의 OBD-Ⅱ Monitioring을 위한 특성 조절
송진우(Jinwoo Song),강희천(Heecheon Kang),한현식(Hyunsik Han) 한국자동차공학회 1999 한국자동차공학회 춘 추계 학술대회 논문집 Vol.1999 No.11_1
Development of tailor-made Pd-only catalyst for CCC application was tried out to achieve the optimized performance of CCC+ UCC system and the reliable 080-11 monitoring, based on the OSC deterioration of CCC with mileage. From the OSC and catalytic activity evaluation for powder and honeycomb catalysts, we found that it could be possible to a 이 ust CO and NOx performance without significant change in HC performance by choosing the proper OSC material. Also it was found that the catalyst with different OSC material showed a different pattern of OSC deterioration with engine bench aging.
이태우(Taewoo Lee),하재어(Jaeau Ha),한현식(Hyunsik Han) 대한기계학회 2011 대한기계학회 춘추학술대회 Vol.2011 No.10
In case of engine for construction machine which has low temperature combustion technology, it is possible to reduce a burden of catalytic system because low PM and NOx are emitting. But, it is difficult to meet Tier4F regulation without after-treatment system. So, we need to optimize the performacne of catalytic system installed in construction machine which has low temperature combustion technology.