RISS 학술연구정보서비스

검색
다국어 입력

http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.

변환된 중국어를 복사하여 사용하시면 됩니다.

예시)
  • 中文 을 입력하시려면 zhongwen을 입력하시고 space를누르시면됩니다.
  • 北京 을 입력하시려면 beijing을 입력하시고 space를 누르시면 됩니다.
닫기
    인기검색어 순위 펼치기

    RISS 인기검색어

      검색결과 좁혀 보기

      • 좁혀본 항목

      • 좁혀본 항목 보기순서

        • 원문유무
        • 음성지원유무
          • 원문제공처
          • 등재정보
          • 학술지명
          • 주제분류
          • 발행연도
          • 작성언어
          • 저자

        오늘 본 자료

        • 오늘 본 자료가 없습니다.
        더보기
        • 무료
        • 기관 내 무료
        • 유료
        • 엔진연소실에서 아세톤 형광을 이용한 공연비 측정기법 연구

          오승묵(Seungmook Oh),강건용(Kernyong Kang),박승재(Seungjae Park),허환일(HwanilHuh) 한국자동차공학회 2002 한국자동차공학회 Symposium Vol.2002 No.11

          Planar laser induced fluorescence(PLIF) has been widely used to obtain two dimensional fuel distribution.<br/> Preliminary investigation was performed tomeasure quantitative air excess ratio distribution in an engine fueled with<br/> LPG. It is known that fluorescence signal from acetone as a fluorescent tracer is less sensitive to oxygen quenching<br/> than other dopants. Acetone was excited by KrF excimer laser (248nm) and its fluorescence image was acquired by<br/> ICCD camera with a cut-off filter to suppress Mie scattering from the laser light. For the purpose of quantifying PLIF<br/> signal, an image processing method including the correction of laser sheet beam profile was suggested. Raw images<br/> were divided by each intensity of laser energy and profile of laser sheet beam. Inhomogeneous fluorescence images<br/> scaled with the reference data, which was taken by a calibration process, were converted to air excess ratio<br/> distribution. This investigation showed instantaneous quantitative measurement of planar air excess ratio distribution<br/> for gaseous fuel.

        • 과급에 의한 바이오디젤의 저온연소 운전영역 확장에 관한 연구

          오승묵(Seungmook Oh),장재훈(Jaehoon Jang),이용규(Yonggyu Lee),이선엽(Sunyoup Lee) 대한기계학회 2011 대한기계학회 춘추학술대회 Vol.2011 No.10

          바이오디젤 연료는 그 안에 포함된 산소성분으로 인해 압축착화엔진에 사용했을 때 일반디젤 연료보다 더 적은 입자상 물질을 배출한다. 따라서 이 연료를 저온연소 기법에 적용하는 경우 보다 효과적으로 NOx-PM을 동시 저감할 수 있고 그로부터 저온연소 운전영역의 확장을 기대할 수 있다. 이번 연구에서는 일반디젤과 대두유 기반의 바이오디젤 연료를 이용하여 Dilution controlled regime에서의 저온연소 운전을 구현하고 성능 및 배기 특성을 조사하였다. 엔진 실험 결과로부터 바이오디젤 연료의 경우 디젤에 비해 약 14% 낮은 발열량에도 불구하고 높은 세탄가 및 함산소 성질로 인한 연소효율 증가로 동일 연료량 분사 시 이보다 더 낮은 약 10~12% 정도의 출력이 감소함을 볼 수 있었다. 배기 측면에서도 바이오디젤 내 산소원자가 입자상물질의 산화반응을 촉진하여 최대 90%의 smoke 저감이 가능하며 THC, CO 역시 감소함을 관찰하였다. 또한 엔진 과급 실험으로부터 과급을 사용하여 저온연소 및 바이오디젤 사용으로 인한 출력 저하를 개선할 수 있음을 확인하였으며 과급과 바이오디젤 연료의 동시적용을 통해 더 적은 EGR 가스 투입으로도 저온연소에 상응하는 PM-NOx 동시 저감이 가능함을 보여주었다. 이런결과는 결국 이와 같은 과급 및 바이오디젤 연료의 적절한 조합으로부터 엔진 출력 향상과 배기특성 개선이 동시에 달성할 수 있음을 의미하며 이로부터 운전영역의 확대가 가능함을 제시하였다. Due to its O content, biodiesel (BD) has benefits in lowering PM in CI engines. This ability can make the fuel considered as one of the best candidates for LTC operation since use of BD can extend the regime for simultaneous reduction of PM and NOx. Thus, in this study, LTC operation was realized with BD and diesel at 5~7% O2 fraction. Engine test results show that use of BD raised efficiency and reduced emissions such as PM, THC and CO while IMEP was decreased by 10~12% due to lower LHV of the fuel. Especially, smoke was suppressed by up to 90% since O atom in BD enhanced soot oxidation reaction. To compensate IMEP loss, turbocharging (TC) was then tested and the results show that not only was power output increased but also PM was reduced further. Moreover, TC in BD engine operation allowed a similar level of reduction in both NOx and PM at 11~12% O2 fraction, meaning that there is a potential to widen the operating range by the combination of TC and BD.

        • 석유액화가스엔진에서 수소첨가에 의한 희박연소 특성 연구

          오승묵(Seungmook Oh),김정환(Junghwan Kim),이용규(Yonggyu Lee) 한국추진공학회 2014 한국추진공학회 학술대회논문집 Vol.2014 No.12

          Combustion and emission characteristics were investigated in LPG engine with hydrogen addition. At λ=1.7 and 2.0, high combustion stability was found with hydrogen even though its change was small at λ=1.0 and 1.3. Stable operation of the engine was presented even at λ=2.0, if the amount of hydrogen gas was near 63% volume fraction (15% of total energy). High in-cylinder temperature due to hydrogen combustion resulted in further heat loss to surroundings. Except for λ=1.0, with larger blending of hydrogen, CO was reduced significantly but it was not the case at the leaner region. Nitric oxides(NOx) was increased slightly with hydrogen at λ=1.0 and 1.3. However, when λ>1.3, its relative amount of emission was low. NOx was continuously decreased with hydrogen. However, at λ=2.0 NOx was lowered to a factor of 100 at λ=1.0. THC emission was significantly increased as air/fuel ratio close to leaner region due to misfire and partial burn.

        • KCI등재

          대형 액상분사식 LPG 엔진의 희박연소특성에 관한 연구

          오승묵(Seungmook Oh),김창업(Changup Kim),강건용(Kernyong Kang),우영민(Youngmin Woo),배충식(Choongsik Bae) 한국자동차공학회 2004 한국 자동차공학회논문집 Vol.12 No.4

          Combustion and fuel distribution characteristics of heavy duty engine with the liquid phase LPG injection(LPLI) were studied in a single cylinder engine. Swirl ratio were varied between 1.2, 2.3, and 3.4 following Ricardo swirl number(Rs) definition. Rs=2.3 showed the best results with lower cycle-by-cycle variation and shorter burning duration in the lean region while strong swirl(Rs=3.4) made these worse for combustion enhancement. Excessive swirl resulted in reverse effects due to high heat transfer and initial flame kernel quenching. Fuel injection timings were categorized with open valve injection(OVI) and closed valve injection(CVI). Open valve injection showed shorter combustion duration and extended lean limit. The formation of rich mixture in the spark plug vicinity was achieved by open valve injection. With higher swirl strength(Rs=3.4) and open valve injection, the cloud of fuel followed the flow direction and the radial air/fuel mixing was limited by strong swirl flow. It was expected that axial stratification was maintained with open-valve injection if the radial component of the swirling motion was stronger than the axial components. The axial fuel stratification and concentration were sensitive to fuel injection timing in case of Rs=3.4 while those were relatively independent of the injection timing in case of Rs=23.

        • KCI등재

          LPG엔진에서 수소연료 보조분사에 의한 희박연소특성 연구

          오승묵(Seungmook Oh),김창업(Changup Kim),강건용(Kernyong Kang) 한국자동차공학회 2006 한국 자동차공학회논문집 Vol.14 No.2

          The basic effects of hydrogen addition for engine performance and emission were investigated in single cylinder research engine. Seven commercial injectors were tested to choose a suitable injector for hydrogen injection prior to its engine implementation. The hydrogen fuel leakage and flow rate were evaluated for each injector and KN3-1(Keihin, CO.) showed the best performance for hydrogen fuel. At the higher excess air ratio(λ=1.7, 2.0), the better combustion stability was found with hydrogen addition even though its effect was small at lower excess air ratio (λ=1.0, 1.3). Stable operation of the engine was even guaranteed at λ=2.0, if the amount of hydrogen gas was near 15% of total energy. In the lean region, λ>1.3, thermal efficiency was improved slightly while it was not clearly observed at λ=1.0, 1.3. It is considered that, in some cases, high temperature environment due to hydrogen combustion caused further heat loss to surroundings. Except for λ=1.0, with larger amount of hydrogen addition, CO was reduced drastically but it was emitted more at the leaner region. Nitric oxides(NOx) was increased a little more with hydrogen addition at λ=1.0, 1.3. However, at λ>1.3 its relative amount of emission was low. In addition, the amount of NOx was continuously decreased with hydrogen addition, but, at λ=2.0 the amount of NOx was lowered to 1/100 of that of λ =1.0. THC emission was significantly increased as air/fuel ratio was raised to leaner region due to misfire and partial burn.

        • KCI등재

          전기점화 엔진에서 개질가스 첨가에 의한 희박연소특성 연구

          오승묵(Seungmook Oh),김창업(Changup Kim),강건용(Kernyong Kang),최영(Young Choi) 한국자동차공학회 2006 한국 자동차공학회논문집 Vol.14 No.3

          Hydrogen can extend the lean misfire limit to a large extent when it is mixed with conventional fuels for a spark ignition engine. In this study, hydrogen-enriched gaseous fuels by reforming process were simulated according to their proportions of H₂, CO, CO₂ and N₂ gases. Pure hydrogen and two different hydrogen-enriched gaseous mixtures(A-, B-composition) were tested for their basic effects on the engine performances and emissions in a single cylinder research engine. A- and B-composition showed different results from 100% H₂ addition because air/fuel mixtures were more diluted by their additions. Even though the energy fraction of reformed gases was increased, combustion stabilities and lean misfire limits were not sensitively improved. It means that combustion augmentation by H₂ addition was offset by the charge dilution of N₂ and CO₂. In addition, the low flammability of CO gas deteriorated thermal efficiencies. CO emission was drastically increased with B-composition which included higher CO component. However, NOx was reduced as energy fraction(Xe) rised except for the case of 100% H₂ addition at λ=1.2 and was , for A-composition, lowered to a factor of ten when compared with that of H₂ addition. HC emissions were largely influenced by COVimep due to misfire and partial burns.

        • 직접분사식 LPG 및 가솔린 엔진의 연소 및 배기특성 비교 연구

          오승묵(Seungmook Oh),이석환(Seokhwan Lee),조준호(Junho Cho),차경옥(Kyoungok Cha) 한국자동차공학회 2009 한국자동차공학회 학술대회 및 전시회 Vol.2009 No.11

          Combustion and emission characteristics of LPG(Liquefied Petroleum Gas) and gasoline fuels were compared in a single cylinder engine with direct fuel injection. While fuel injection pressure and IMEP(indicated mean effective pressure) were varied with 60, 90, 120 bar and 2 to 10 bar, another parameters for the engine operation as engine speed, air excess, and fuel injection timing were fixed at 1500 rpm, 1.0, and BTDC 300 CA respectively. Experimental results show that MBT timing for LPG is less sensitive to IMEP, and its combustion stablility(COVIMEP) is also better than gasoline fuel. However, LPG is found that thermal efficiency has lower values a little due to increase of pumping loss by higher throttling inherently. Gasoline shows longer burn durations in the early stage of combustion(10% MBF), but when considering total burn duration(90% MBF) gasoline was shorter than LPG for over IMEP 7 bar. Hydrocarbon emissions of gasoline rise to a level of three-fold than those of LPG. In addition, nitric oxides has higher values for gasoline but carbon monoxide for both fuels shows similar level for all test conditions

        맨 위로 스크롤 이동