• Journal of Advanced Marine Engineering and Technology
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• 제28권3호
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• pp.475-481
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• 2004

Recently it is strongly required on lower fuel consumption. lower exhaust emission, higher engine performance. and social demands in a spark ignition gasoline engine. In this study. the experimental engine used at test. it has been modified the lean burn gasoline engine. and used the programmable engine management system, and connected the controller circuit which is designed for the engine control. At the parametric study of the engine experiment, it has been controlled with fuel injection, ignition timing. swirl mode, equivalence ratio engine dynamometer load and speed as the important factors governing the engine performance adaptively. It has been found the combustion characteristics to overcome the hysteresis phenomena between normal and lean air-fuel mixing ranges. by mean of the look-up table set up the mapping values. at the optimum conditions during the engine operation. As the result, it is found that the strength of the swirl flow with the variation of engine speed and load is effective on combustion characteristics to reduce the bandwidth of the hysteresis regions. The results show that mass fraction burned and heat release rate pattern with crank angle are reduced much rather, and brake specific fuel consumption is also reduced simultaneously.

• 한국분무공학회지
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• 제9권2호
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• pp.9-17
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• 2004

The performance characteristics of lean burn system in gasoline engine are mainly affected by the air-fuel mixture in cylinder, gas exchange process of manifold system, exhaust emission of engine, and the electronic engine control system. In order to obtain the effect of performance factors on the optimum conditions of lean burn engine, this study deal with the behavior of mixture formation, gas flow characteristics of air, flow and evaporation analysis of spray droplet in cylinder, vaporization and burning characteristics of lean mixture in the engine, and the control performance of electronic engine control system. The optimum flow conditions were investigated with the swirl and tumble flows in the combustion chamber with swirl control valve. The performance characteristics and optimum condition of flow field in intake system were analyzed by the investigation of inlet flow of air and combustion stabilization on cylinder.

• 대한기계학회논문집B
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• 제38권10호
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• pp.837-844
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• 2014

최근 자동차 제조사는 강화되는 배출가스 규제를 만족시키고 엔진 효율을 향상시키기 위해 다양한 기술을 연구하고 있다. 그 중 직접분사식 초희박 연소기술은 정밀한 연소제어를 통해 연소효율을 극대화 하고 연비를 향상시킬 수 있는 차세대 기술로 평가받고 있다. 기존 가스엔진에 초희박 직접분사기술을 적용하기 위해 기존의 MPI 엔진의 헤드를 재설계하였다. 기존 압축비10:1에서 12:1로 증가시킴으로써 이에 따른 압력선도, 열방출률, 연료소비율 등의 연소특성과 배출가스특성을 파악하였다. 압축비를 증가시킴에 따라 불안정한 연소상태로 인하여 연료소비율의 개선이 어려웠으나 탄화수소(THC)와 질소산화물(NOx)의 배출은 감소되었다.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 동계학술발표대회 논문집
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• pp.340-344
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• 2008

The importance of the more efficient cogeneration system is emphasized. Also the more clean energy is needed at recent energy system. The cogeneration system using Lean burn engine is more preferred to the system using Rich burn engine because of the electrical efficiency. Although the cogeneration system using Lean burn engine is economically preferred, because of the NOx emission level, the system using Rich burn engine with 3-way catalyst can only be used in Korea. The NOx regulation level is 50ppm at oxygen level 13%. The cogeneration hybrid system using Lean burn engine is up to be optimized because of the large amount of the extra-fuel at the after-burner system. The after-burner system at different concept was applied. The reduction time for the activation temperature of the DeNOx catalyst was achieved by making a hole between the combustor and boiler. Because of the lowered fuel consumption, the lowered temperature level was optimized by blocking the hole of the boiler The optimized cogeneration hybrid system consumes $76Nm^3/h$ LNG to produce 150kW electricity compared to before optimization $103Nm^3/h$ LNG. The system was accurately evaluated and the result is following ; 90% total efficiency, below 10 ppm NOx, 50ppm CO, 25ppm HC. The cogeneration hybrid system can meet the current NOx level and exhaust gas regulation. It can achieve the clean combustion gas and efficient cogeneration system.

• 한국수소및신에너지학회논문집
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• 제28권2호
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• pp.174-180
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• 2017

Recently, the world faces the environmental problem such as air pollution due to harmful gas discharged from car and abnormal climate due to the green-house gases increased by the discharge of $CO_2$. Compressed Natural Gas (CNG), one of alternative for this problem, is less harmful, compared to the existing fossil fuel, as gaseous fuel, and less carbon in fuel ingredients and carbon dioxide generation rate relatively favorable more than the existing fuel. However, CNG fuel has the weakness of slow flame propagation speed and difficult fast burn. On the other hand, hydrogen does not include carbon in fuel ingredients, and does not discharge harmful gas such as CO and HC. Moreover, it has strength of quick burning velocity and ignition is possible with small ignition energy source and it's has wide Lean Flammability Limit. If using this hydrogen with CNG fuel, the characteristics of output and discharge gas is improved by the mixer's burning velocity improved, and, at the same time, is possible to have stable lean combustion with the reduction of $CO_2$ expected. Therefore, this research tries to identify the characteristics of engine and emission gas when mixing CNG fuel and hydrogen in each portion and burning them in spark igniting engine, and grasp the lean combustion limit and emission gas characteristics according and use it as the basic data of hydrogen-CNG premixed engine.

• 한국자동차공학회논문집
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• 제20권3호
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• pp.106-112
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• 2012

Since air pollution problem by emissions from automotive vehicles has become social issues, lean-burn gasoline direct injection (GDI) engine is focused as an alternative to meet the requirement of reinforced emission regulation and improved fuel consumption. Spray-guided type DI combustion is promising technology, which characterized by the centrally mounted injector and closely positioned spark plug, since stable lean combustion can be realized even at ultra-lean mixture condition. In the present study, the effect of multi-ignition with developed charge coil on combustion and emission characteristics was investigated in optical accessible single cylinder engine. In order to fully understand the in-cylinder phenomena and the mechanisms of emission production, optical diagnostics, such as flame visualization was also carried out at frequently using operating condition. Multi-ignition is effective to improve fuel economy but increase NOx emission at flammability limit.

• 대한기계학회논문집B
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• 제21권1호
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• pp.36-48
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• 1997

In order to establish the ignition system for lean burn, the influence of the number of spark plug, spark times and spark intervals on discharge pattern of spark energy on ignitability and combustion characteristics were evaluated. It showed that, ignitability remarkably increased with the case of multiple spark ignition system than with the case of single spark and the lean limit extended fuel/air equivalence ratio by 0.1, the increase of magnitude and lasting time of capacity component and inductance component was multi spark discharge in a row.

• 한국자동차공학회논문집
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• 제8권1호
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• pp.1-9
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• 2000

In the present study, the IDI-type constant volume chamber, which utilizes the indirect injection stratified charge method, is used to solve several problems including misfires and cycle-variations caused by unstable initial ignitions. A subchamber has been used to make an ignitable mixture under the low mean equivalence ratio. After burned in the subchamber, the flame jet getting through the passage hode enters the main chamber and burns the lean charge. There are many factors which affect the combustion characteristics of the indirect injection stratified engine. The passage hole angle is the most important since it determines the direction of flame flows into the main chamber. In the present study, we measured the combustion pressure, and the wall temperature, and computed the heat flux through the cylinder wall in order to understand the combustion characteristics depending on passage hole angle and the equivalence ratio.

• 대한기계학회논문집
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• 제17권6호
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• pp.1633-1639
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• 1993

본 연구에서는 급속연소기술의 가솔린엔진에 적용을 목적으로 흡입과정시 강한 와류(swirl)를 생성하는 마스크부착 헤드(masked shroud head, MSH)형을 급속연 소형으로 제작하여 마스크부착 헤드형에서의 급속연소효과를 이온전류법에 의한 화염 속도를 측정하므로서 규명하려한다. 이온전류는 이온탐침계(ion probe)를 연소실 표면의 두 지점에 설치하여 검출하며, 이온전류 신호를 정성적인 방법으로 검증한 후 표준 헤드형과 마스크부착헤드형을 장착한 엔진에 대해서 화염전파 속도를 비교 측정 한다. 측정된 화염 전파속도는 정확한 연소특성 분석을 위해 각 사이클에서의 값을 표본으로 하는 통계적 방법으로 처리한다.

• 한국자동차공학회논문집
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• 제12권2호
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• pp.45-53
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• 2004

An experimental study was carried out to obtain the fundamental data about the effects of radicals induced injection on premixture combustion. A constant volume combustor divided to the sub-chamber and the main chamber was used. The volume of the sub-chamber is set up to occupy less than 1.5％ of that of whole combustion chamber. Radial twelve narrow passage holes are arranged between the main chamber and the sub-chamber. The products including radicals generated by spark ignition in the sub-chamber will derive the simultaneous multi-point ignition in the main chamber. While the equivalence ratio of pre-mixture in the main chamber and the sub-chamber is uniform. We have examined the effects of the sub-chamber volume, the diameter of passage hole, and the equivalence ratio on the combustion characteristics by means of burning pressure measurement and flame visualization. In the case of radical ignition method(RI), the overall turning time including the ignition delay became very short and the maximum burning pressure was slightly increased in comparison with those of the conventional spark ignition method(SI), that is, single chamber combustion without the sub-chamber. The combustible lean limit by RI method is extended to more ER=0.25 than that by SI method. Therefore the decrease of every emission including NOx and the improvement of fuel consumption is anticipated due to lean burn.