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성용하(Yongha Sung),박성용(Sungyong Park),김화남(Hwanam Kim),최병철(Byungchul Choi),임명택(Myung Taeck Lim) 한국자동차공학회 2009 한국자동차공학회 학술대회 및 전시회 Vol.2009 No.11
Although premixed compression ignition combustion can simultaneously reduce NOx and PM emissions in the diesel engine, all of the experimental PCI engines are reported to emit HC and CO at such a high level as that of the gasoline engines. DOC's can effectively oxidize HC and CO, but the low exhaust temperature of the PCI engines makes the problem rather difficult. In this study several DOC's for PCI engines are designed and tested with model gas as well as exhaust gas of a PCI engine, and their performance characteristics are discussed. One of these experimental DOC's showed higher PM conversion when compared with conventional diesel oxidation catalysts. A DOC with a particular type of washcoat showed a lower light-off temperature as well as better thermal durability. DOC's proved to be more effective in oxidizing PM in PCI engine exhaust gas because of the high fraction of SOF than in conventional diesel engine exhaust.
성용하(Yongha Sung),김화남(Hwanam Kim),정길성(Kil Sung Jung),임명택(Myung Taeck Lim),최병철(Byungchul Choi) 한국자동차공학회 2007 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
Exhaust treatment devices are added to the diesel engines as stricter regulations are introduced worldwide. The objectives of this study arc to further understand the characteristics of exhaust nanoparticles from a common-rail diesel engine equipped with DOC, DPF or CPF, and to analyze the effects of ultra-low sulfur diesel fuel on the particulate emissions. Diesel fuel with sulfur supplied in engine under the conditions of various equivalence ratio, fuel supply pressure and engine speed. The particle size distribution is measured by an SMPS to investigate the influences of sulfur content of the fuel, fuel injection pressure, fuel-air equivalence ratio, engine speed and load, types of exhaust treatment devices etc.
직분 방식 급속압축팽창기를 이용한 DME 균일 혼합기의 압축 착화 연소
성용하(Yongha Sung),정길성(Kil Sung Jung),임명택(Myung Taeck Lim) 한국자동차공학회 2005 한국자동차공학회 춘 추계 학술대회 논문집 Vol.2005 No.5_1
Compression ignition of homogeneous charges in IC engines offers possibilities of maintaining the high efficiency of DI diesel engines with low level of NOx and particulate emissions. The objective of this study is to further understand the characteristics of the HCCI(Homogeneous charge compression ignition) combustion and to find ways of extending the rich HCCI operation limit in engine-like environment. DME is supplied either in the form of premixture or directly injected in the combustion chamber of a rapid compression and expansion machine under the conditions of various equivalence ratio and injection timing. The cylinder pressure is measured and the rate of heat release is computed from the measured pressure for the analysis of the combustion characteristics. The experiments show that the RCEM can operate without knock on mixtures of higher equivalence ratio, when DME is directly injected in the combustion chamber than introduced as a fraction of perfect or nearly perfect premixture. Very early fuel injection timings have only insignificant effects in control of ignition timing.
성용하(Yongha Sung),임명택(Myung Taeck Lim),정길성(Kil Sung Jung),최병철(Byungchul Choi) 한국자동차공학회 2007 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
Compression ignition of homogeneous charges in IC engines proposes possibilities of achieving the high thermal efficiency of DI diesel engines with low level of NOx and particulate emissions of SI engines. The objectives of this study are to further understand the characteristics of the HCCI (Homogeneous charge compression ignition) combustion, and to find practical ways of extending the rich HCCI operation limit in an engine-like environment. DME fuel is supplied either in the form of premixture with air or directly injected in the combustion chamber of a rapid compression and expansion machine under the conditions of various equivalence ratio and injection timing. The cylinder pressure is measured and the rate of he at release is computed from the measured pressure for the analysis of the combustion characteristics. Exhaust emissions are analyzed by an FT-IR (Fourier transform infrared) and a CLD(Chemiluminescent Detector). The experimental data to date show that the RCEM operates without knock on mixtures of higher equivalence ratio and exhaust emissions reduced when DME is directly injected than inducted as perfect or nearly perfect premixture.
정길성(Kil Sung Jung),김화남(Hwanam Kim),성용하(Yongha Sung),최병철(Byungchul Choi),임명택(Myung Taeck Lim) 한국자동차공학회 2006 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
HCCI engines exhaust gas that contains THC and CO at a level comparable to the gasoline engines. Development of exhaust treatment devices like DOC's with high conversion efficiency especially at low temperature is therefore very important for commercialization of HCCI engines. Experimental DOC's are designed and fabricated in this study using 600 cpsi monolith, coated with either a L type or H type wash coat. Different amount of platinum is impregnated on the washcoat layers before canning and performance tests. Experimental results show that DOC's with low-temperature type wash coat have higher HC conversion efficiency at low exhaust gas temperature in comparison with those of high-temperature type wash co at and heavier Pt loading. DOC's with heavier Pt loading show higher HC conversion efficiency at exhaust temperature over 300℃. CO conversion is above 90 % on all types of DOCs as long as the exhaust temperature stays over 200 ℃.
정길성(Gil Sung Jung),정종우(Jong-Woo Jeong),성용하(Yongha Sung),김화남(Hwanam Kim),최병철(Byungchul Choi),임명택(Myung Taeck Lim) 한국자동차공학회 2007 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
HCCI engines are expected to offer the high efficiency of DI diesel engines with low level of NOx and particulate emissions. Experimental HCCI engines are however reported to exhaust THC and CO at a level comparable to the gasoline engines. Because the exhaust gas temperature of HCCI engines is lower than that of the diesel engines, development of exhaust treatment devices like DOC's with high conversion efficiency especially at low temperature is crucial to commercialization of HCCI engines. Experimental DOC's are designed and fabricated in this study using various level of platinum loading and 600 cpsi ceramic monolith coated with two different type of wash coat. Performance test result of these DOC's show that the low-temperature type washcoat effectively lowers the 50% light-of f temperature by 30℃. L90, the catalyst with this type of wash coat and an intermediate level of level of platinum loading, demonstrates the lowest light-of f temperature in the model gas tests.