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Sangyul Lee,Jongyoon Lee,Seungkwon Hwang,Taejoong Wang,Youngbok Lee 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.9
To comply with the new non-road emission standards, final Tier 4, two big strategies have been applied to the 11 L heavy-duty diesel engine. The first strategy is to apply Exhaust gas recirculation and selectivity catalytic reduction system to meet the NOx limitation. The other one is to apply low swirl ratio (for higher volumetric efficiency) and multi-hole nozzle, a high pressure direct injection, and an optimized combustion system in order to reduce PM emission. Both strategies put a focus on the optimization of combustion system. In this study, a ULPC bowl concept applied in the previous works has been successfully verified in 11 L heavy-duty diesel engine with wellvalidated 3D combustion simulation, and the ULPC bowl shape has been geometrically optimized. A rough 0D calculation is used to calculate the fuel split ratio of the various ULPC bowl shapes. In the rated-power operating condition of the final Tier 4 engine which is deduced by 1D cyclic simulation, the optimal fuel split ratio of the injected fuel has been verified. Also, additional geometric optimization has been achieved without changing the optimal fuel split ratio. From these results, soot has been reduced by about 30% with ULPC optimum bowl shape against the Tier 3 re-entrant bowl shape.
Sangyul Park,Hasun Lee,Dongjun Lee 제어로봇시스템학회 2020 제어로봇시스템학회 국제학술대회 논문집 Vol.2020 No.10
We propose CPG (central pattern generator) based robot control framework constructed based on: 1) the inverse model of the CPG that directly encodes resultant body motion of the robot in CPG parameters; and 2) the CPG parameter adaptation law that enforces robustness of the controller. These two components behaves as feedforward and feedback control for the CPG controlled robot, enabling us to achieve fast and robust generation of a desired body motion for robotic systems operated within complex environmental interaction. The inverse CPG model is constructed based on neural network along with autoencoder to efficiently deal with the dimension decrease from input to output of the model. Also, the CPG parameter adaptation is done with a concept of backpropagation, which is enabled by the adoption of smooth activation function for the inverse CPG model. For the development and verification of the proposed framework, simulation is conducted with two robotic systems, snake-like robot and pivotboard system.
이상율(Sangyul Lee) 한국고고학회 2001 한국고고학보 Vol.45 No.-
최근 天安 斗井洞 및 龍院里古墳群에서는 百濟의 初期馬具相을 알 수 있는 중요한 유물이 출토되었다. 정식보고된 바에 의하면 모두 4世紀代의 것들로 규정되고 있다. 주지하듯이 이 시기는 남부지방에서 진정한 騎乘用 馬具가 도입되는 시기이다. 그러나 지금까지 金官加耶를 비롯한 일부 특정지역을 제외하고는 특히, 百濟의 경우 4世紀代의 馬具 全形은 거의 알려지지 않고 있었다. 따라서 兩유적에서 출토된 馬具가 4世紀代의 것이 분명하다면, 百濟 初期馬具의 實相을 직접 보여주는 자료가 되는 점에서 매우 중요한 것이 된다. 또한 馬具는 특정지역을 뛰어넘어 巨視的인 문화상을 반영하는 특징을 갖고있기 때문에 百濟馬具에 있어서 해당 시기에 다른 지역과의 교류나 특징을 파악해 낼 수 있게 된다. 따라서 兩유적의 馬具를 보다 정확히 파악하기 위하여 개개의 檢證을 통해 새로이 살펴본 후, 같은 시기의 자료가 풍부한 加耶馬具와 비교하여 검토해 보았다. 그 결과, 斗井洞의 馬具는 4世紀의 늦은 시기, 龍院里의 馬具는 이보다 더욱 늦은 5世紀後葉부터 6世紀代에 걸친 자료로 파악하였다. 따라서 이들 馬具만으로는 百濟 初期馬具의 구체적인 실상을 파악할 수 없음을 알았다. 특히 龍院里의 馬具는 斗井洞을 잇는 연장선상에서 百濟의 4世紀代를 대변하는 자료가 되지 못함을 지적하였다. 한편 龍院里에서는 비교적 古式에 속하는 劍菱形杏葉이 출토되었다. 그 특징을 통해 최근 논의되고 있는 起源문제에 재접근을 시도해 본 결과, 역시 同形式으로서는 最古式에 속하는 것이 아님을 알 수 있었다. 그러나 이 杏葉 및 지금까지 출토된 初期資料의 검토를 통해 과거 주장한 바 있는 劍菱形杏葉의 百濟起源 가능성을 다시 제시해 보았다. Recently, the important remains that told something about the early forms of horse trappings in Baekjae were excavated in Cheonan Doojeong-Dong and Yongwon-Ri ancient tombs. According to the official report, they are all from the 4th century. As widely known, this is the period when true horse trappings were beginning to be introduced in the southern parts. However, the whole form of horse trappings was not discovered so far, especially in the case of Baekjae, except some particular areas like Gumgwankaya. Thus, if the remains from the two tombs turn out to be from the 4th century, they are very important in that they could show the actual state of early horse trappings of Baekjae. Moreover, since horse trappings reflect the macroscopic images of culture, going beyond a certain area, they could also reveal some facts about trades in the period. Therefore, to better examine the horse trappings excavated in both remains, they were individually verified and compared with the horse trappings from the same period Gaya, whose materials are abundant. According to the result, the trappings from Doojeong-Dong were made in the late 4th century, whereas the ones from Yongwon-Ri were much later than that, that is, in the late 5th and 6th century. Thus, it was impossible to find out the specific facts on the early Baekjae horse trappings from these materials. It was also pointed out that the horse trappings from Yongwon-Ri could not represent the 4th century of Baekjae since they are on the extended line of Doojeong-Dong. Yongwon-Ri also produced Gumnung-type harness pendants, which is relatively an old form. The study on their origin through the features revealed that they did not belong to the oldest type in the same form. However, by examining these pendants and the early materials excavated so far, the possibility of the pendants having originated in Baekjae was suggested again.
부분 예혼합 압축착화 연소를 위한 다단 분사 및 피스톤 보울 형상에 관한 연구
이상열(Sangyul Lee),박원아(Wonah Park),민경덕(Kyoungdoug Min) 한국자동차공학회 2009 한국자동차공학회 부문종합 학술대회 Vol.2009 No.4
To reduce diesel engine emission, partially homogeneous charge combustion ignition diesel engine with split injection was simulated. Some conditions compared to the conventional injection strategy were evaluated and soot was reduced but NOx was not. Due to the early injection, pressure and temperature in the piston is low and spray was collided to the piston liner, combustion was poor and HC and CO would be increased. To eliminate the collision, retarded the injection timing and modified the bowl geometry and NOx and soot is reduced a bit quantity. At last, piston bowl was modified for spray reentrance. In this results, NOx and soot was enomously reduced..
이상열(Sangyul Lee),장서윤(Seoyun Jang),박원아(Wonah Park),박철웅(Cheolwoong Park) 대한기계학회 2019 大韓機械學會論文集B Vol.43 No.7
연료 분사 모듈은 대표적인 중소기업 아이템 중의 하나이나, 대부분의 업체들이 체계적인 설계기술 및 설계 tool을 확보하고 있지 못한 실정이다. 연료 분사 모듈 설계에 사용되는 기존 상용 설계 및 해석 프로그램은 고비용과 전문성의 한계로 인해 중소기업에서 활용하기 힘든 측면이 있다. 이런 이유로, 국내 노즐 업체들이 쉽게 사용할 수 있는 연료 분사용 노즐 설계/해석 tool 개발의 필요성이 제기되고 있다. 본 연구는 연료분사모듈 설계 프로그램용 코드 구조를 개발하고 플랫폼 연동용 input/output 코드를 개발하는 것을 연구 목표로 하였다. 오픈소스 3D 연소해석 프로그램인 KIVA의 서브루틴을 분석한 후 분사 모듈 개발에 필요한 코드를 개발하고, 기존 코드 및 실험결과와 비교, 검증하였다. Fuel injection module is one of the representative small and medium enterprise items, but most companies do not have systematic design technology and design tool. The existing commercial design and analysis programs used in fuel injection module design are difficult to utilize in SMEs due to their high cost and limited expertise. For this reason, there is a need to develop fuel injection nozzle design / analysis tool which domestic nozzle manufacturers can easily use. The purpose of this study is to develop code structure for fuel injection module design program and to develop input / output code for platform linkage. After analyzing the subroutines of KIVA which is an open source 3D combustion simulation program, we developed the code necessary to develop the injection module and compared it with the results of the old code and experiments.
이상열(Sangyul Lee),민경덕(kyoungdoug Min) 한국자동차공학회 2011 한국자동차공학회 학술대회 및 전시회 Vol.2011 No.11
Simulation results are able to provide the insights of engine cylinder. Generally, chemical mechanism of n-heptane is used as a fuel of engine combustion, because diesel fuel consists of hundreds of chemical components and various chemical classes and it is very complex and huge to use to the calculation. In this study, n-dodecane was used as a representative fuel to describe the heavy molecular weight of diesel oil (C10~C20). We added and modified some reactions based on the reduced high-temperature n-dodecane chemical mechanism and developed a new reduced diesel surrogate chemical mechanism with the basic mechanism consists of iso-octane and toluene. In addition, reactions of diacetylene and naphthalene were added to describe the processes of soot formation. The ignition delay times of the new reduced diesel surrogate chemical mechanism were well matched to the experimental data. This reduced diesel surrogate chemical mechanism would be used to the engine simulation well due to the small number of reaction and species.