• Proceedings of the KAIS Fall Conference
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• 2009.12a
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• pp.526-530
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• 2009

본 연구은 자동차용 가솔린엔진에 장착되는 인젝터의 연료공급 특성에 대한 것으로, 가솔린 엔진의 전자제어식 포트 연료분사는 분무장치와 흡기포트의 최적화 및 분무특성이 우수해야 엔진의 성능 향상 및 배기가스 저감의 목적을 이룰 수 있다. 4홀과 12홀 인젝터의 장착각 변화와 포트 마스킹의 형상변화에 따른 벽유량을 측정?분석하였고 분무가시화 실험을 통하여 분무성장과정과 분사각, 연료미립화 및 분무도달거리를 분석하였다. 벽류측정 실험을 통하여 벽류는 미립화정도와 흡기유동과 유속에 가장 큰 영향을 받는 것으로 판단되며, 12홀 인젝터 대비 4홀 인젝터는 분무압력에 따라 분무특성의 변화량이 크게 나타났다.

• Journal of computational fluids engineering
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• v.4 no.3
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• pp.21-27
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• 1999

In this paper, tile characteristics of flow resulting from the configurations of piston head and intake-port of the cylinder in a gasoline-direct-injection engine are investigated numerically. Calculations are carried out from intake process to the end of compression. GTT code which includes the third order upwind Chakravarthy-Osher TVD scheme and κ-ε turbulence model with the law of wall as a boundary condition. As a result, a piston head with a smaller radius of curvature and larger radius gives stronger reverse tumble. It is also shown that as the maximum tumble ratio increases by the configuration of the intake-port the tumble ratio at the end of compression stroke increases. It is concluded that flows at the end of compression stroke can be controlled by the optimum design of intake-port and piston head.

• Journal of ILASS-Korea
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• v.23 no.1
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• pp.36-41
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• 2018

Fuel wall film effects power output and cycle deviation by changing the amount of fuel flowing into cylinder in PFI gasoline engines. Reduction of wall film can reduce fuel consumption and improve combustion stability. In this research, the effects of injection strategies including injection pressure and dual injection system is investigated for reducing wall film formation. The CONVERGE software is used for numerical analysis tool and O'Rourke film splash model was used for wall film prediction model. Compared with the reference case wall film decreased with increase of injection pressures, and the film formation reduced when the dual injection system was used.

• Journal of ILASS-Korea
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• v.23 no.2
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• pp.96-101
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• 2018

The purpose of this study is to investigate the effect of water injection on combustion characteristics of gasoline direct injection (GDI) engine with turbo-charger under low-load operating condition. The test engine used in this study has four-cylinder and 10.2 of compression ratio. In order to study the effect of water injection ratio on combustion characteristics, the water was injected into the intake port from 10% to 50%, based on fuel injection quantity. From the experiment, it revealed that the water injection induced the improvement of fuel economy because of the advance of spark-timing by the reduction of in-cylinder temperature. In addition, the water injection caused the prolong of extension of the ignition delay and slight increase of burn duration.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.3
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• pp.42-49
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• 2014

The gasoline direct injection (GDI) system is considerably spreading in automotive market due to its advantages. Nevertheless, since GDI system emit higher particle matter (PM) due to its combustion characteristics, it is difficult to meet strengthened emission regulation in near future. For this reason, a combined GDI with MPI system, so-called, dual injection (DUI) system is being investigated as a supplemental measure for the GDI system. This paper focused on power and fuel consumption effect by injection mode strategy of DUI system in part load and idle engine operating condition. In this study, port fuel injectors are installed on 2.4 liters GDI production engine in order to realize DUI system. And, at each injection mode, DOE (design of experiment) method is used to optimize engine control parameters such as dual injection ratio, start of injection timing, end of injection timing, CAM position and so on. As a consequence, DUI mode shows slightly better or equivalent fuel efficiency compared to conventional GDI engine on 9 points fuel economy mode as well as MPI mode shows less fuel consumption than GDI mode during idle operation. Furthermore, DUI system shows improvement potential of maximum 2.0% fuel consumption and 1.1% performance compared to GDI system in WOT operating condition.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.4
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• pp.351-358
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• 2015

In the recent times, the use of gasoline direct injection (GDI) engines has been regarded as a means of enhancing conformance to emission regulations and improving fuel efficiency. GDI engines have been widely adopted in the recent years for their better engine performance and fuel economy compared to those of conventional MPI gasoline engines. However, they present some disadvantages related to the mass and quantity of particulate matter generated during their use. This study investigated the nanoparticle characteristics of the particulate matter exhausted from a GDI engine vehicle installed with different types of gasoline particulate filters, after subjecting it to ultra-lean burn driving conditions. Three metal foam and metal fiber filters were used for each experimental condition. The number concentrations of particles were analyzed for understanding their behavior, and the reduction characteristics were obtained for each type of filter.

• Journal of ILASS-Korea
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• v.15 no.2
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• pp.61-66
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• 2010

Fuel spray characteristics of the gasoline engine injector has been studied experimentally. To provide fundamental performance data of 4-hole and 12-hole injectors, spray fuel-mass distribution, wall wetting fuel amount and visualization of injectors have been tested and measured with various fuel supply pressure conditions. Spray visualization has been performed to analyze spray formation, spray angle, stream width and penetration length. Test result shows that wall wetting is greatly influenced by the induction air amount and spray atomization. Spray visualization shows that the 12-hole injector has robust performance characteristics with various fuel supply pressure conditions compared with the 4-hole injector. 4-hole injector generates relatively less wall-wetting fuel amount than 12-hole injector does.

• Journal of Power System Engineering
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• v.16 no.5
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• pp.5-12
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• 2012

희박예혼합기의 급속연소에 관한 연구를 위하여 2-실린더 가솔린 엔진을 부실 타입의 압축천연가스(CNG) 분사 엔진으로 개조하였다. 본 연구에서는 부실의 최적설계에 관심을 두고 두 종류의 부실을 적용하여 실험을 실시하였고, 부실의 체적과 홀 개수는 1.5cc와 6개로 각각 동일하게 하고, 홀 직경을 0.8mm 및 1.1mm로 달리하였다. CNG연료는 포트연료분사(Port fuel injection; PFI)와 부실분사(Sub-chamber injection; SCI)에 의해 엔진에 독립적으로 공급되고, 그 실험결과로 구한 연소압력, 평균유효압력(IMEP), 질량연소분율과 사이클변동계수(COV) 등을 서로 비교하였다. 본 연구의 대표적 실험연구결과로서 PFI 타입의 엔진연소특성은 희박예혼합기의 경우를 제외하고 모든 조건에 있어서 기존의 가솔린 엔진과 비슷하였고, SCI 타입의 엔진연소특성으로 평균유효압력은 부실 내에 불완전 예혼합기형성으로 PFI 타입보다 낮았으며, COV는 SCI 타입이 희박가연한계가 확대됨으로 인하여, 특히 높은 공기과잉률 범위에서 PFI 타입과 비교해 보다 좋은 결과를 나타내었다.

• Proceedings of the KAIS Fall Conference
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• 2009.05a
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• pp.539-542
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• 2009

본 연구은 자동차용 가솔린엔진에 장착되는 인젝터의 연료공급 특성에 대한 것으로, 4홀과 12홀 인젝터의 분무질량분포, 벽류 및 가시화 실험을 수행하였다. 분무질량분포 실험을 통하여 인젝터 별 분무특성을 파악하고, 벽류측정실험을 통하여 흡기포트내의 연료 Wetting 특성을 확인하였다. 가시화실험을 통하여 분사각과 분무특성을 비교 분석하였다. 4홀과 12홀 인젝터의 분무특성비교를 통한 각 인젝터의 연료공급 특성분석은 가솔린엔진 설계시 기초자료로 활용될 수 있을 것이다.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.2
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• pp.121-127
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• 2011

NOx (Nitrogen Oxide) reduction system periodically needs a rich or stoichiometric operating condition to reduce NOx. A new method that optimizes the control of external HC injection into a diesel exhaust pipe for HC-type LNT (Lean NOx Trap) catalyst system has been developed. In this paper, these catalysts are called HC-LNT catalysts. The concentration and amount of HC can be controlled by controlling the external injection. In this study, we investigated the relationship between the spray behavior of hydrocarbons injected into the transparent exhaust pipe and NOx reduction characteristics. From the results of this experiment, we obtained useful information about the optimum injection and position of HC injector to the exhaust pipe. Further, we obtained useful information about the optimal injection condition for an HC-LNT catalyst system with a gasoline PFI (port fuel injection) typeinjector.