DME-LPG HCCI 엔진에서 LPG 조성과 분사량이 연소에 미치는 영향

오창훈(Changhoon Oh),장진영(Jinyoung Jang),배충식(Choongsik Bae) 한국자동차공학회 2009 한국자동차공학회 학술대회 및 전시회 Vol.2009 No.11

The effect of the composition(propane(C₃H?), butane(C₄H?)) and injection quantity of liquefied petroleum gas (LPG) was investigated in a di-methyl ether (DME)-LPG dual-fuel homogeneous charge compression ignition (HCCI) engine. The composition of LPG and injection quantity affects DME-LPG dual fuel HCCI combustion because LPG suppresses low temperature reaction of DME which results retardation of high temperature reaction. It was found that ignition delay was prolonged as injection quantity of LPG increased. Ignition delay was more prolonged when propane was used due to better anti-knock property compared to butane. Thus, high load operating regime was extended by addition of LPG, and further expanded when propane was used. However, at the same condition, amount of heat release rate per heating value of injected fuel was decreased because of suppression of low temperature reaction of DME, which affects heat release amount of entire combustion reaction. In terms of emissions, carbon monoxide (CO) and nitrogen oxide (NOx) emissions were strongly dependent on combustion temperature while hydrocarbon(HC) emission was proportional to amount of LPG injected compared to injected DME. In case that injected quantity of LPG was equal, there were disadvantages of HC and NOx emissions and advantage in CO emission when propane was used.

도시구성요소 기반 운전자 멘탈 모델을 반영한 차량용 네비게이션 시스템 제안

오창훈(Changhoon Oh),엄 지(Eom Ji) 한국HCI학회 2013 한국HCI학회 학술대회 Vol.2013 No.1

차량용 네비게이션을 이용한 길찾기가 보편화되고 있다. 사람들은 네비게이션을 일종의 보철지식으로 활용 하여 자신의 인식범위 밖의 지리정보를 알 수 있으며, 거리낌없이 새로운 장소를 찾아 나선다. 그런데 이러한 네비게이션 시스템의 대부분은 거리예측기반 turn-by-turn안내의 형식으로 이루어진다. 본 연구는 이러한 기본 네비게이션 길찾기 안내가 운전자의 길찾기 멘탈 모델과 어긋나 있음을 문제상황으로 보고, 운전자 길찾기 멘탈 모델을 해당 개념의 원형인 케빈 린치의 The Image of the City로부터 출발한다. 린치가 주장한 다섯 가지 도시 요소를 검토한 후 이를 바탕으로 길찾기에 관한 파일럿 인터뷰를 진행하고, 분석내용을 반영한 태스크를 설계하여 실험한 후, 디자인 임플리케이션을 도출한다. 도출한 내용을 반영하여 프로토타입을 제작하고 사용성을 평가하여 유의미한 결과를 얻는 것이 본 연구의 목표이다. Way finding using car navigation system is becoming more common. People use navigation as a sort of prosthetic knowledge, which enables drivers to know geographic information beyond their own knowledge and to find any places freely. Most commercial navigation services are providing information using turn-by-turn function based on distance expectation. This study sets the situation where the basic principle of commonly used navigation system and way finding mental model of drivers are discrepant as a problem and then introduces Kevin Lynch’s ‘Image of the City’, which covered the concept of way finding for the first time. In this study, we interview drivers and conduct driving tasks, inducing some design implications. Then we prototype navigation function and evaluate the usability.

직접분사식 가솔린 엔진에서 에탄올 혼합연료의 분무 및 연소특성

오희창(Heechang Oh),Wang Hua,오창훈(Changhoon Oh),박정서(Jungseo Park),배충식(Coongsik Bae) 한국자동차공학회 2009 한국자동차공학회 학술대회 및 전시회 Vol.2009 No.11

An experimental study was carried out to investigate the effect of ethanol concentration in ethanol blended gasolone on spray characteristics, engine performance and emissions in a single cylinder spray guided direct injection spark ignition engine. The planar laser induced fluorescence and planar Mie scattering macroscopic spray imaging were conducted using simulated fuel. Ethanol showed faster evaporation, enhanced local homogeneity and smaller liquid phase area near the spark plug. The For the engine experiment, it was shown that increased ethanol concentration in ethanol blened gasoline gives wider stratified combustion range in terms of injection timing due to faster evaporation, lower combustion instability and NOx emission due to enhanced local homogeneity and increased IMEP because additional retardation of injection is available.

가솔린 직분사 엔진에서 휘발유의 산소 함량이 입자상 물질 배출에 미치는 영향

차규섭(Gyusob Cha),오창훈(Changhoon Oh) 한국자동차공학회 2012 한국자동차공학회 학술대회 및 전시회 Vol.2012 No.11

The impact of oxygen content in gasoline and the particulate emission (particle number and weight) on GDI engine was investigated. Three vehicles, two equipped with direct injection and one with port fuel injection were tested on the chassis dynamometer. In order to control oxygen content, methyl tert-butyl ether (MTBE) - most commonly used oxygenate in Korea -was used. In addition, eight different test fuels, which have different octane number and oxygen content, were used. The oxygen content in the gasoline was varied from 0 to 3 wt%, which corresponds with an MTBE dosage from 0% to 16.11%. All vehicles were tested with Federal Test Procedure-75 (FTP-75) cycle. The experimental results showed that the oxygen content increases in the gasoline reduced the particulate emission in vehicles with direct injection engines. In case of port fuel injection engine, although the absolute quantity was much smaller than that of the direct gasoline engine, however, the same phenomenon was observed. Other factors such as fuel economy or other exhaust emissions(Carbon monoxide, Hydrocarbon, Nitrogen oxides) were not significantly affected by the oxygen content.

원심 압축기 볼루트 성능 해석

김우준(Woojune Kim),오창훈(Changhoon Oh),조경석(Kyungseok Cho) 한국유체기계학회 2006 유체기계 연구개발 발표회 논문집 Vol.- No.-

A volute (or scroll) of a centrifugal compressor collects the flows from impeller or diffuser, and passes it to a pipe at the exit. This flow still contains some kinetic energy which is not converted into pressure at diffuser, thus volute designer must concern the way to minimize losses. This study defines some variables which determine the shape of volute, and carry out computational analysis based on Design of Experiment to optimize the performance of volute.

레이저 유도 플라즈마 분광분석법을 이용한 연성회로기판 절단 공정에서의 탄화 특성 계측

류훈철(Hoonchul Ryoo),이형우(Hyungwoo Lee),오창훈(Changhoon Oh),한재원(Jaewon Hahn) 한국레이저가공학회 2008 한국레이저가공학회 학술대회 논문집 Vol.2008 No.-

In the present study, the carbon contamination generating from the laser based cutting process of flexible printed circuit board (FPCB) is characterized by molecular spectrum emission of carbon using the technique of laser induced breakdown spectroscopy (LIBS). Using KrF excimer laser the spectrum emission of polyimide film ranging from 250 nm to 700 nm is analysed and from the result, the dominant spectrum emission of carbon contamination is identified by the C₂swan band. The total emission area of C₂swan band ranging from 500 nm to 517 nm is compared according to the laser repetition rate. Increasing the repetition rate, the integrated emission area has a tendency to decrease exponentially. When the energy per pulse of the laser decreases as 74% in comparisin between 20 Hz and 150 Hz operation condition of repetition rate, the integrated emission area decreases rapidly as 15 %. The result shows that in the cutting process of FPCB using UV laser, the reduction of pulse energy has a strong influence on the generation of carbon contamination.

국내 언론에 나타난 가상 인간 윤리 이슈 파악: 의미연결망 분석을 중심으로

장서진(Seojin Jang),한다은(Daeun Han),오창훈(Changhoon Oh) 한국디지털콘텐츠학회 2022 한국디지털콘텐츠학회논문지 Vol.23 No.11

Virtual humans have emerged as a new digital service following the COVID-19 pandemic. However, there is also a concern that the technology could be misused. We collected 139 Korean media reports on virtual humans and analyzed them through semantic networks using UCINET 6 to identify the ethical issues of virtual human. The study findings are as follows: It is important to discuss the ethical issue of virtual humans in terms of the overall process of their development and their use. Regarding policies and regulations relating to virtual humans, discussions on ‘job replacement’, ‘violation of personal rights’ and ‘diversity’ are urgently required. Virtual humans are also subject to issues like sexual harassment, appearance judgement, hatred, and other types of discrimination that affect humans. There are also issues related to ‘crime’, ‘portrait rights’, ‘dignity’, ‘right to be forgotten’, etc., when a virtual human is created after the appearance of a real human. Lastly, the development phase of virtual humans should take into consideration factors like ‘trust’, ‘personal information leakage’, ‘bias’, and ‘prejudice.’