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스파크 점화기관의 냉시동시 배기밸브 타이밍 및 점화시기 변화에 따른 배기가스의 온도변화
김득상(Duksang Kim),이종영(Jongyoung Lee),이용희(Yonghoe Lee),조용석(Yongseok Cho) 한국자동차공학회 2004 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
Experimental study of variation of exhaust gas temperature was carried out with the changes of spark timing and exhaust valve timing during the cold start operation of an SI engine. To investigate the effects of these variables on combustion stability, cylinder pressure and exhaust gas temperature were measured and analyzed. Experimental results showed that exhaust gas temperature increased when spark and exhaust valve timings were retarded from the baseline cases. However, combustion stability during cold start deteriorated under the retarded conditions. To increase exhaust gas temperature for fast warmup of catalysts while maintaining combustion stability, an optimal condition for spark and valve timing retard should be appied for the cold start period.
[가솔린엔진부문] 미연 배기가스 점화 제어기술을 이용한 배기저감
김득상(Duksang Kim),강봉균(Bonggyun Kang),김성철(Sungchul Kim),이상진(Sangjin Lee),양창석(Changsuck Yang),조용석(Yongseok Cho) 한국자동차공학회 2001 한국자동차공학회 춘 추계 학술대회 논문집 Vol.2001 No.11_1
UEGI (Unburned Exhaust Gas Ignition) is expected to help faster warm up of a close-coupled catalytic convener (CCC) by igniting the unburned exhaust mixture using two glow plugs installed in the upstream of the catalyst. In this study, a control module and an algorithm for the UEGI technology was developed. It changes I/O signals from the ECU, and controls ignition signals, glow plug on/off signals, and cooling water temperature signals to modify AIF ratios during cold start of the test engine. The control module is also designed to be readily applicable to a conventional vehicle, therefore, its repeatability, stability of UEGI flame, precision of light-off time and performance characteristics were tested and analyzed on an engine test bench. In addition, both the UEGI system and a hydrocarbon adsorber were applied to the exhaust system for more effective reduction of HC emission during the cold start period. Experimental results show that the CCC reaches the light-off temperature faster compared with the Baseline exhaust system, and HC and CO emissions are reduced significantly during the cold star1. The UEG I control module proved its effectiveness in precise control of the UEGI system.<br/> <br/> <br/> <br/> - 74p<br/> <br/> <br/> <br/> This paper proposes a method to detect the misfired cylinder using Exhaust Pressure Ascent Rate.<br/> If a misfire occurs, the engine will be lost some power and consumes the more fuel and the torque will be unsteady. Most of all, the misfire affects a bad influence of the 3-way catalyst and emits unburned hydrocarbon in the air.<br/> To prevent these unusual phenomena and eliminate the factor of the environmental pollution. It is an important thing to detect the misfired cylindere.<br/> Experimental results showed that the method using the exhaust pressure ascent rate is proven to be effective in the detection of misfired cylinder on gasoline engine regardless loads and revolutions of the engine
EURO-VI 대응 상용 디젤자동차의 후처리시스템 적용 기술
김득상(Duksang Kim),왕태중(Taejoong Wang) 한국자동차공학회 2013 오토저널 Vol.35 No.9
위에서 소개한 바와 같이 EURO-VI 배기규제 이후로부터는 승용 소형자동차와 상용 대형 디젤자동차의 배기규제 수준은 거의 동등 수준으로 유지될 것으로 예상되고 있다. 승용과 상용 모두 이러한 지속적인 배기규제 강화는 매우 높은 수준의 기술적 도전과 직면하는 것이며, 특히 상용 자동차의 경우 차량의 운전특성 및 소비자의 요구가치가 승용차와 다른 점이 많으므로 보다 다양한 관점에서 기술적 대안을 검토해야 할 필요성이 높다. 향후 본격적인 온실가스 규제 및 CO2 규제가 발효되면 그동안 소비자 가치로 인식되어 온 연비가 적극적인 규제 대상이 될 것으로 보이며, 이에 따라 연비 향상 기술이 배기규제 만족을 위한 필수 기술로 인식될 것으로 보인다. 즉, 엔진의 연소 및 후처리기술의 지속적인 발전과 더불어, 배기열 회수기술 및 Turbo-compounding과 같은 연비개선 기술이 점차 일반화될 가능성이 높으며, 이러한 기술의 도입 및 적용은 기존의 연소시스템 및 후처리시스템과 통합적으로 관리, 운용되어야만 배기 및 연비규제에 동시에 대응 가능한 기술로 정착될 수 있을 것으로 보인다. 또한 Off-highway 장비인 건설장비, 굴삭기, 비도로용 트럭, 발전기 및 선박에 이르는 다양한 Heavy-Duty 장비에도 EURO-VI 동등 수준의 배기규제 강화가 지속적으로 논의되고 있으며, 이에 대한 적극적인 기술 개발이 꾸준히 이루어져야 할 것으로 생각한다.
[가솔린엔진부문] 잔류가스 추정 기법을 이용한 EGR율의 예측
김성철(Sungcheol Kim),이상진(SangJin Lee),김득상(Duksang Kim),엄인용(Inyong Ohm),조용석(Yong-Seok Cho) 한국자동차공학회 2001 한국자동차공학회 춘 추계 학술대회 논문집 Vol.2001 No.11_1
Residual gas acts as a diluent which results in reducing the in-cylinder temperature as well as the flame speed, significantly affecting fuel economy, NOx emissions and combustion stability. Therefore it is important to determine the residual gas fraction as a function of the engine operating parameters accurately. However, the determination of the residual gas fraction is very sophisticated due to the unsteady state of induction and exhaust process. There has been little work toward the development of a generally applicable model for quantitative predictions of residual gas fraction
고온고압 조건에서 Two-Photon LIF를 이용한 CO 측정에 관한 연구
오승묵(Seungmook Oh),김득상(Duksang Kim),Paul C. Miles,Will F. Colban 한국연소학회 2007 한국연소학회지 Vol.12 No.4
Carbon monoxide (CO) is not only an important intermediate species in chemical reaction mechanisms of hydrocarbon fuel combustion, but also a crucial pollutant species emitted from automotive engines. To better understand the physical processes impacting CO emissions, the development of laser-based measurement techniques that can visualize in-cylinder CO distributions is desirable. Among these techniques, Laser-Induced Fluorescence (LIF) is a sensitive and species-selective detection technique capable of good spatial resolution. However, some technical matters such as deep UV excitation, severe pressure dependency of the LIF signal, and potential interference from other species have been major challenges for CO LIF application. This study is focused on investigating the feasibility of CO two-photon LIF in a direct-injection diesel engine operating at typical pressure and temperature conditions with commercial grade diesel fuel. Spectroscopic analysis shows that the CO fluorescence signal can be separated from C₂ Swan band or broadband fluorescence from PAHs when the signal is collected near 483 nm. The signal-to-noise ratio of CO LIF deteriorate rapidly as pressure is increased, following P<SUP>-1.49</SUP> which matches the theoretical signal pressure dependency.
디젤엔진 연소실 형상 강건최적화(DFSS)설계를 통한 2.4L ULPC 엔진 연비개선에 관한 연구
유덕근(Dockoon Yoo),김득상(Duksang Kim) 한국추진공학회 2014 한국추진공학회 학술대회논문집 Vol.2014 No.12
본 논문은 Tier 4-Final 배기규제를 DPF 없이 만족시키는 2.4L ULPC 디젤엔진의 낮은 수준의 배기가스를 유지한 채 피스톤 형상을 최적화하여 엔진 연비를 개선한 연구 결과이다. 본 연구에서는 연소실 형상 최적화를 위해 3D 연소해석을 기반으로 한 DFSS(Design for Six Sigma)의 강건 최적화 설계기법이 사용되었다. 이를 통해 연비개선을 위해 분사시기 진각에 따른 soot 배출 감수성을 낮추는 강건 최적화 개념이 도입된 연소실 형상(RD1과 RD2)이 도출되었다. 엔진 성능 시험을 통해 강건 최적화된 연소실의 연비개선 가능성을 검증하였다. 최종적으로 RD2 연소실 형상이 장착된 엔진에서 최대 출력조건에서 2.4%, 배기가스 인증 모드인 NRSC에서 3.0%, NRTC에서 4.9%의 연비를 개선하는 결과를 보여주었다. This paper explains a detailed review of improved BSFC of 2.4L ULPC(Ultra Low Particulate Combustion) diesel engine by optimizing the piston bowl geometry while maintaining non-DPF solution for Tier 4 Final emission regulation. In this study, 3-D combustion simulation and robust optimal design method by DFSS (Design for Six Sigma) were used to optimize the piston bowl geometry. Two piston bowl geometries (RD1 and RD2) were derived from adopting design process based on DFSS. These pistons showed enhanced robustness on injection timing which could inhibit increasing soot emission. It means that these have potentials to improve thermal efficiency and fuel consumption. Results from engine bench tests proved the potential of improved fuel consumption by virtue of robust designed piston bowl geometries and these test data are well-matched the simulation. Finally, RD2 piston bowl can improve 2.4% fuel consumption under the rated power condition and 3.0% and 4.9% of fuel consumption improvements were achieved under NRSC and NRTC test cycles, respectively.