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LPG 액상분사식 인젝터 분사팁의 아이싱 발생 특성 연구
박철웅(Cheolwoong Park),김창업(Changup Kim),최교남(Kyonam Choi),강건용(Kernyong Kang) 한국자동차공학회 2006 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
The use of clean gaseous fuel for the purpose of high efficiency and low emission in automotive engines has tendency of increase in order to meet the reinforcing emission regulations and to efficiently utilize limited natural resources. Since the liquid phase LPG injection (LPLI) system has a very strong potential to accomplish the higher power, higher efficiency, and lower emission characteristics than the mixer type fuel system, automotive companies developed and commercialized it. However, when a liquid LPG fuel is injected into the inlet duct of an engine, a large quantity of heat is extracted due to evaporation of fuel. This leads to freezing of the moisture in the air around the outlet of a nozzle, which is called icing phenomenon. It may cause damage to the outlet nozzle of an injector or inlet valve seat. This research examines the characteristics of icing phenomenon and also aimed to improve it through the use of anti-icing bushing at the fuel injection tip. The result showed that the icing phenomenon and process were mainly affected by humidity and temperature of inlet air in the inlet duct. Also, it was observed that the icing phenomenon improved by using aluminum bushing whose end matches the end of fuel injection tip in length.
EGR을 적용한 하이브리드용 가솔린 엔진의 성능 및 배출특성에 대한 연구
박철웅(Cheolwoong Park),김창기(Changgi Kim) 한국자동차공학회 2007 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
EGR(exhaust gas recirculation) is considered as a most effective method to reduce the NOx emissions. But high EGR tolerance is always pursued not only for its advantages of the pumping loss reduction and fuel economy benefit in Gasoline-Hybrid engine. However, the occurrence of excessive cyclic variation with high EGR normally prevents substantial fuel economy improvements from being achieved in practice. Therefore, the optimum EGR rate should be carefully determined in order to achieve low fuel consumption and low exhaust emission. In this study, 2 liters gasoline engine with E-EGR system was used to investigate the effects of EGR on fuel efficiency, combustion stability, engine performance and exhaust emissions. With optimal EGR rates, the fuel consumption was improved by 4%. This improvement was achieved while a reduction in NOx emissions of 75% was accomplished.
HCNG 엔진의 터보차저 변경에 따른 전부하 출력 및 배출가스 특성 연구
박철웅(Cheolwoong Park),김창기(Changgi Kim),임기훈(Gihun Lim),이성원(Sungwon Lee),최영(Young Choi),이선엽(Sunyoup Lee) 한국가스학회 2013 한국가스학회지 Vol.17 No.5
천연가스에 수소를 첨가하는 수소-천연가스 혼합연료 (HCNG) 엔진 기술은 수소의 빠른 화염속도와 넓은 가연범위를 이용하여 출력 및 배기성능을 최적화하는 기술로서 희박연소 한계를 증가시킴으로써 열효율의 개선은 물론 유해배출물의 저감을 얻을 수 있다. 그러나 과급장치를 사용하는 희박연소 엔진의 경우 전부하 운전조건에서 희박연소 한계의 증가는 충분한 공기량을 공급할 수 있도록 과급용량의 증가가 선결되어야 구현될 수 있다. 본 연구에서는 HCNG 엔진 개발의 일환으로 과급시스템의 변경에 의한 엔진의 출력특성을 파악하고, 과급용량 증대의 적용가능성을 검토하고자 하였다. 터보차저가 과급압력의 증대 보다는 유량이 증가된 영역에서 효율이 높게 설계된 경우 농후한 혼합기 조건에서는 과급압력이 감소되더라도 제원상의 출력을 만족하며 효율적인 운전이 가능하였다. Hydrogen-natural gas blends(HCNG) engine is optimizing technology of performance and emission characteristics with use of hydrogen’s fast flame speed and wide flammability limit. As lean-burn limit is extended, the improvement in thermal efficiency and harmful emissions can be achieved. However, the extension of lean-burn limit under a wide open throttle operation point could be realized with the increase in boosting capacity in a lean-burn engine with turbo-charging system. In the present study, the power output characteristics of HCNG engine with turbo-charger change is assessed and feasibility of the increase in boosting capacity is evaluated. The turbo-charger design with high efficiency at higher flow rate rather than higher boosting pressure makes efficient operation possible at relatively rich mixture condition.
직접분사식 희박연소 LPG엔진에서 흡배기 밸브시기가 연소 및 배기특성에 미치는 영향
박철웅(Cheolwoong Park),김태영(Taeyoung Kim),조시현(Seehyoen Cho),오승묵(Seungmook Oh) 대한기계학회 2015 大韓機械學會論文集B Vol.39 No.1
최근 강화되는 연료소비율과 배기 규제에 대응하기 위해 자동차용 엔진에 다양한 신기술들이 적용되고 있다. 직접분사식 희박연소 엔진은 안정적인 성층혼합기 연소를 통해 연료소비율 및 배출가스 개선이 가능하지만 과잉공기 조건에서 상대적으로 높은 수준은 질소산화물의 배출은 해결되어야 할 과제이다. 본 연구에서는 직접분사식 희박연소 LPG 엔진에서 가변 밸브 기구를 이용한 흡기 및 배기밸브 시기의 변경이 엔진의 성능 및 배출가스에 미치는 영향을 파악하고자 하였다. 스로틀링을 하지 않은 부분부하 운전 조건에서 흡기밸브 열림 시기의 진각은 공기과잉률의 증가에 의한 질소산화물 배출 증가에 원인으로 작용하였다. 배기밸브 열림 시기를 진각할 경우 팽창일 감소와 펌핑손실 증가에 의해 연료소비율이 악화되었다. In order to meet the enforced emission regulations and reduce fuel consumption, various new technologies are employed in engines. The problem of NOx emissions under a lean mixture condition should be solved, because a lean-burn direct-injection engine can realize stable lean combustion with a stratified mixture, which results in improvements in fuel economy and emissions. This study investigated the effects of intake and exhaust valve timing changes on the performance and emission characteristics of a lean-burn LPG direct-injection engine. Under a partial-load operating condition without throttling, an increase in the intake valve opening led to an increase in NOx emissions due to an increase in the amount of excess air. The fuel consumption deteriorated with an increase in the exhaust valve opening due to a decrease in the expansion work and an increase in the pumping loss.
하이브리드용 가솔린 엔진에서 최적 EGR적용에 따른 성능 및 배출가스 특성 분석
박철웅(Cheolwoong Park),최영(Young Choi),김창기(Changgi Kim) 한국자동차공학회 2008 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
EGR(Exhaust gas recirculation) provides an important contribution in achieving the development targets of low fuel consumption and low exhaust emission levels on gasoline-hybrid engines while allowing stoichiometric fuelling to be retained for applications using the three-way catalysts. However, the occurrence of excessive cyclic variation with high EGR normally prevents substantial fuel economy improvements from being achieved in practice. Therefore, the optimum EGR rate in Gasoline-Hybrid engine should be carefully determined in order to achieve low fuel consumption and low exhaust emission. In this study, 2 liters gasoline engine with E-EGR system was used to investigate the effects of EGR with optimum EGR rate on fuel economy, combustion stability, engine performance and exhaust emissions. As the engine load becomes lower, the EGR rate is increased. The increase in engine load and reduction in engine speed make the fuel consumption better. The fuel consumption was improved by maximum 5.5% at low speed, high load operating condition.