• 한국분무공학회지
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• 제19권4호
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• pp.221-226
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• 2014

This paper described the effect of split injections on the stability of combustion and emission characteristics in a direct injection gasoline engine at various operating conditions. In order to investigate the influence of direct injection gasoline engine, the fuel injection timing was varied direct fuel injection at various fuel pressure. The experimental apparatus consisted of GDI engine with 4 cylinder, EC dynamometer, injection control system, and exhaust emissions analyzer. The emission and combustion characteristics were analyzed for the fuel injection timing and fuel injection pressure strategies. It is revealed that CO and HC emissions are dramatically decreased at advanced injection timing. Also, engine performance is increased at increase fuel injection pressure.

• 한국분무공학회지
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• 제25권2호
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• pp.51-59
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• 2020

The purpose of this study is to propose and compare methods for measuring individual spray cone angles using spray cross-section images. In direct injection gasoline engines, it was believed that the distribution of air-fuel mixture in the combustion chamber directly affected combustion performance and emission formation. However, since gasoline direct injection (GDI) injectors have a small injection angle, interference between individual spray plumes occurs. Therefore, GDI injectors have only measured the spray angle of the entire spray. To overcome these limitations, three methods of indirectly measuring the spray cone angles of individual spray plume were presented and compared by forming sheet beams using Nd:YAG laser and acquiring spray cross-section images. Each method currently has advantages and disadvantages, and research to apply the method suitable for various GDI injectors needs to be continued.

• 대한기계학회논문집B
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• 제36권2호
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• pp.137-143
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• 2012

현재 세계적으로 배출가스 규제 강화와 유가 상승으로 인해 가솔린엔진에서 배출되는 유해 배출 가스 저감기술 및 연비향상 기술 개발이 절실히 요구되고 있다. 가솔린 직접분사(GDI; Gasoline direct injection) 기술은 가솔린 연료를 직접 연소실에 분사하여 정밀한 연소제어를 통해 매우 희박한 혼합기에서도 고효율의 연소가 가능하게 함으로써 연비저감과 고출력을 동시에 만족할 수 있는 효과적인 기술이다. 본 연구에서는 분무유도방식(spray-guided type)을 이용한 GDI 엔진을 개발하여 안정적인 희박연소를 구현하였다. 자주 사용되는 운전영역에서 연료분사시기의 TDC(Top dead center) 인근으로의 지각을 통하여 안정적인 희박연소를 구현하였으며, 다단분사를 적용하여 추가적인 연료소비율의 개선이 가능한 반면 탄화수소(THC)와 질소산화물($NO_x$)의 배출은 증가하고 CO의 배출은 감소되었다.

• 한국분무공학회지
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• 제20권3호
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• pp.156-161
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• 2015

This paper described the effect of dual clutch transmissions on the stability emissions characteristic in a GDI engine at vehicle Inspection and Maintenance(I/M) program. In order to investigate the influence of direct injection gasoline engine with DCT, the experimental apparatus consisted of GDI engine with 4 cylinder, dynamometer and exhaust emissions analyzer. Analyzed emission gas include CO, HC and NOx results that DCT vehicle in the case of NOx, HC in automatic transmission vehicles less than 1/2 level was confirmed to be exhausted. However vehicle specific power increases CO also has increased.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2014년도 제49회 KOSCO SYMPOSIUM 초록집
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• pp.347-348
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• 2014

After-treatment system for gasoline direct injection engines should be considered due to the regulation standard for particle number emitted from spark ignition engine vehicles. A metal foam particulate filter, which is thought to be more proper for gasoline engines for its unique filtration and heat resistance characteristics, has been evaluated via engine dynamometer tests.

• 한국자동차공학회논문집
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• 제7권6호
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• pp.65-71
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• 1999

Recently new engine system is being required to cope with intensive emission restriction . For this reason, GDI(Gasoline direct injection) engine system which can satisfy both as good fuel economy as diesel engine and the performance to surpass PFI gasoline engine is being development . Since fuel injection system plays a significant role in GDI engine performance, the investigation of the spray characteristics injected from GDI injector above all is indispensable for GDI system development. In this study , spray developing shape was visualized using laser sheet with Nd : YAG laser and atomization characteristics was analyzed by measuring velocities and droplet size with PDA. Utilizing these results , the basic design factor of GDI injector can be offered.

• 대한기계학회논문집B
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• 제26권7호
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• pp.1047-1054
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• 2002

To improve the fuel consumption and exhaust emission for gasoline engines, GDI(Gasoline Direct Injection) system was spotlighted to solve above requirements. Thus, many researchers have been studied to investigate the spray characteristics and the mixture formation of GDI injector. In this study, we tried to study the spray characteristics of a gasoline direct injector by using entropy analysis and PlV methods. The entropy analysis is based on the concept of statistical entropy, and it identifies the degree of homogeneity in the fuel concentration. The PlV method was adopted to determine the fluid dynamics information at the spray. From the applied results on a direct injection gasoline spray, we could find that the direct diffusion phenomena was a dominant factor in the formation of a homogeneous mixture at downstream of GDI spray especially under vaporizing ambient conditions, and mixing phenomena was also progressed by momentum exchange with induced air. In addition, the correlation between entropy and vorticity strength enabled to find their relation.

• 대한기계학회논문집B
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• 제36권3호
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• pp.335-342
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• 2012

자동차배출가스는 이산화탄소($CO_2$)에 의한 지구온난화 및 탄화수소(HC)와 질소산화물($NO_x$)에 의한 오존 생성을 야기하는 등, 인체와 환경에 나쁜 영향을 미치기 때문에 이에 대한 관심이 증폭되고 있다. 가솔린 직접분사 (Gasoline Direct Injection; GDI)엔진은 디젤엔진과 같이 연소실내에 연료를 직접 공급하는 방식으로서 가솔린엔진의 취약점으로 지적되어 오던 높은 연료소비율 문제를 획기적으로 개선할 수 있는 기술로 평가되고 있다. 본 연구에서는 분무유도방식(Spray-guided type)의 GDI엔진을 이용하여 공기과잉률 2.0 이상의 초희박 연소를 통해 연료소비율을 개선하였다. 추가적인 연료소비율 개선 및 배출가스 저감을 위해 희박연소시 다단 분사전략과 Exhaust Gas Recirculation (EGR)을 적용하였다. 배출가스 수준과 운전성능을 평가하고 이를 배출가스 규제와 비교 검토함으로써 국내 관련기술 개발 방향 및 상용화 가능성에 대해 검토하고자 하였다.

• 대한기계학회논문집B
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• 제25권1호
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• pp.78-86
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• 2001

The Gasoline Direct Injection(GDI) system has been highlighted due to the improvement of fuel consumption and the control of exhaust emission from gasoline engines. The GDI system includes a high injection pressure, smaller mean diameter, good spray characteristics and stability. We were interested in the development for gasoline direct swirl injector(GDSI) in which the swirler is specially designed with an incident angle. Nymerical analysis was utilized to investigate the internal flow of GDSI with a goal to determine the swirl incident angle and needle lift. Accordingly, it describes characteristics of a GDSI in which the flowrate and spray characteristics are satisfied. especially the spray tip penetration decreases, compared with other type GDI, mean diameter of droplets is from 20${\mu}{\textrm}{m}$ to 25${\mu}{\textrm}{m}$ and spray angle ranges from 64$^{\circ}$to 66$^{\circ}$.

• 대한기계학회논문집B
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• 제39권4호
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• pp.351-358
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• 2015

세계적인 배출가스 규제의 강화와 함께 화석 연료의 매장량 감소와 유가 상승은 새로운 엔진 기술 개발을 촉진시켰다. 가솔린 직접 분사(GDI; Gasoline Direct Injection) 엔진은 연료를 직접 연소실에 공급하고 정밀한 연소제어를 통해 공연비가 희박한 혼합 상태에서도 연소가 가능하게 하였는데, 이러한 방식은 기존 포트 분사 엔진보다 연비와 출력을 모두 향상시킬 수 있다. 하지만 GDI엔진은 디젤 엔진의 경우와 마찬가지로 soot 발생률이 높아짐에 따라 입자상 물질의 배출이 증대되는 문제를 안고 있다. 이러한 문제를 해소하고자 본 연구에서는 가솔린 입자상 물질 필터(GPF; Gasoline Particulate Filter)를 개발하여 입자상 물질의 배출정도를 저감시키고자 하였다. 필터의 설계 효율에 따라 3가지의 Metal foam 필터와 단일 Metal fiber 필터를 실험에 적용하여 PM과 PN의 저감률을 비교하였다.