• Title/Summary/Keyword: PFI(Port fuel injection)

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Characteristics of the In-cylinder Flow and Fuel Behavior with Respect to Fuel Injection Angle and Cone Angle in the PFI Dual Injection Engine (PFI Dual Injection 엔진의 연료 분사각도와 분무각에 따른 엔진 내부 유동 및 연료 거동 특성)

  • Lee, Seung Yeob;Chung, Jin Taek;Park, Young Joon;Yu, Chul Ho;Kim, Woo Tae
    • Transactions of the Korean Society of Automotive Engineers
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    • v.23 no.2
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    • pp.221-229
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    • 2015
  • The PFI dual injection engine using one injector per an intake port was developed for solving the DISI engine cost problem. Excellent fuel atomization and targeting of the PFI dual injection engine made enhancement on the fuel efficiency and engine power. In order to develop a PFI dual injection engine, characteristics of the in-cylinder flow and fuel behavior with respect to fuel injection angle and cone angle of the PFI dual injection engine was investigated. Numerical calculation was conducted to analyze 3D unsteady in-cylinder flow and fuel behavior using STAR-CD. The engine operating condition was 2,000rpm at WOT. As a result, the amount of intake air, evaporated fuel and fuel film according to injection angle and cone angle were presented. The results were influenced by interaction between injected fuel and intake port wall.

Effects of Fuel Injection Strategies on Wall Film Formation at Port Injection Gasoline Engine (포트분사식 가솔린엔진에서 연료분사전략이 Wall Film 생성에 미치는 영향 연구)

  • Lee, Ziyoung;Choi, Jonghui;Jang, Jihwan;Park, Sungwook
    • 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.

Comparison of Dynamic Behavior of Droplet Mean Diameter with 2holes-2sprays and 4holes-2sprays Types Injector for Gasoline Engine (가솔린 엔진용 2홀 2분류와 4홀 2분류 타입 인젝터의 액적 평균 직경의 동적 거동 비교)

  • Kim, Beom-Jun;Cho, Dae-Jin;Yoon, Suck-Ju
    • Journal of ILASS-Korea
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    • v.11 no.1
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    • pp.17-23
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    • 2006
  • The influence of fuel spray characteristics on engine performance has been known as one of the major concerns to Improve fuel economy and to reduce exhaust emissions. In general, the UBHC(Unburned Hydrocarbon) emission could be reduced by decreasing the droplet size of the fuel sprays. In PFI (Port Fuel Injection) gasoline engines, the mixture of air and fuel would not be uniform under a certain condition, because the breakup and production of spray droplets are made in a short distance between the fuel injector and intake valve sheat. In this study, were investigated the transient spray characteristics and dynamic behavior of droplets from 2holes-2sprays and 4holes-2sprays type injectors used in PFI gasoline engine. Mean droplet size and optical concentration were measured by LDPA (Laser Diffraction Particle size Analyzer). The variation of droplet mean diameter and optical concentration were measured for understanding the behavior of unsteady spray.

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Various Injection Conditions and Fuel Control of an LPG Liquid Injection Engine (다양한 분사조건과 LPG 액상분사엔진의 연료량 제어)

  • Sim Hansub
    • Transactions of the Korean Society of Automotive Engineers
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    • v.13 no.1
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    • pp.28-35
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    • 2005
  • Fuel injection rate of an injector is affected by various injection conditions such as injection duration, fuel temperature, injection pressure, and voltage in LPG liquid injection systems for either a port-fuel-injection(PFI) or a direct injection(DI) in a cylinder. Even fuel injection conditions are changed, the air-fuel ratio should be accurately controlled to educe exhaust emissions. In this study, correction factor for the fuel injection rate of an injector is derived from the density ratio and the pressure difference ratio. A voltage correction factor is researched from injection test results on an LPG liquid injection engine. A compensation method of the fuel injection rate is proposed for a fuel injection control system. The experimental results for the LPG liquid injection system in a SI-engine show that this system works well on experimental range of engine speed and load conditions. And the fuel injection rate is accurately controlled by the proposed compensation method.

Unsteady spray characteristics of two-holes two-sprays type injectorin PFI gasoline engine (PFI용 2홀 2분무 인젝터의 비정상 분무 특성)

  • Kim, B.J.;Lee, J.H.;Cho, D.J.;Yoon, S.J.
    • Journal of ILASS-Korea
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    • v.10 no.1
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    • pp.43-52
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    • 2005
  • The effect of fuel injection spray on engine performance has been known as one of the major concerns for improving fuel economy and reducing emissions. In general, reducing the spray droplet size could prevent HC emission in gasoline engine. As far as PFI (Port Fuel Injection) gasoline engine is concerned, the mixture of air and fuel may not be uniform under a certain condition, because breakup and production of spray droplets are made in a short distance between the fuel injector and intake valve. This study, by constituting PFI gasoline spray system, was performed to study the transient spray characteristics and dynamic behavior of droplets from 2hole 2spray type injector used in DOHC gasoline engine. Mean droplet size and optical concentration in accordance with various conditions were measured by LDPA and CCD camera. Through this study, the variation of drop size and optical concentration could be used for understanding the behavior of unsteady spray was declared and the existing the small droplets between each pulse spray could be estimated caused to the development of wall film was conformed.

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Unsteady Intermittent Spray Characteristics of PEI Gasoline Injector (PEI용 가솔린 인젝터의 비정상 간헐 분무 특성)

  • Kim Beomjun;Lee Jaiho;Cho Daejin;Yoon Suckju
    • Transactions of the Korean Society of Automotive Engineers
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    • v.13 no.5
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    • pp.64-74
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    • 2005
  • The effect of fuel injection spray on engine performance has been known as one of the major concerns for improving fuel economy and reducing emissions. In general, reducing the spray droplet size could prevent HC emission in gasoline engine. As far as PFI gasoline engine is concerned, the mixture of air and fuel may not be uniform under a certain condition, because breakup and production of spray droplets are made in a short distance between the fuel injector and intake valve. This study, by constituting PFI gasoline spray system, was performed to study the transient spray characteristics and dynamic behavior of droplets from two-holes two-sprays type injector used in DOHC gasoline engine. Mean droplet size and optical concentration in accordance with various conditions were measured by LDPA and CCD camera. Through this study, the variation of drop size and optical concentration could be used for understanding the behavior of unsteady spray was declared and the existing the small droplets between each pulse spray could be estimated caused to the development of wall film was conformed.

Study on the Optimal Injection Condition for HC-LNT Catalyst System for Diesel Engines with a Gasoline PFI Type Injector (가솔린 인젝터를 디젤엔진용 HC-LNT 촉매에 적용하기 위한 최적 분사 조건에 관한 연구)

  • Oh, Jung-Mo;Mun, Woong-Ki;Kim, Ki-Bum;Lee, Jin-Ha;Lee, Ki-Hyung
    • 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.

Diagnosis of the Combustion Characteristics of Spark Ignition Engine with Compressed Natural Gas(CNG) Injection Type (압축천연가스(CNG) 분사식 스파크점화엔진의 연소특성 진단)

  • Ha, D.H.;Jin, J.M.;Hwang, S.I.;Yeom, J.K.;Chung, S.S.
    • 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.

The Combustion and Emission Characteristics with Increased Fuel Injection Pressure in a Gasoline Direct Injection Engine (가솔린 직접 분사식 엔진에서 연료 분사 압력 증가에 따른 연소 및 배기 배출물 특성)

  • Lee, Junsun;Lee, Yonggyu
    • Journal of ILASS-Korea
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    • v.22 no.1
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    • pp.1-7
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    • 2017
  • Recently, Performance and fuel efficiency of gasoline engines have been improved by adopting direct injection (DI) system instead of port fuel injection (PFI) system. However, injecting gasoline fuel directly into the cylinder significantly reduces the time available for mixing and evaporation. Consequently, particulate matters(PM) emissions increase. Moreover, as the emission regulations are getting more stringent, not only the mass but also the total number of PM should be reduced to satisfy the Euro VI regulations. Increasing the fuel injection pressure is one of the methods to meet this challenge. In this study, the effects of increased fuel injection pressures on combustion and emission characteristics were experimentally examined at several part load conditions in a 1.6 liter commercial gasoline direct injection engine. The main combustion durations decreased about $2{\sim}3^{\circ}$ in crank angle base by increasing the fuel injection pressure due to enhanced air-fuel mixing characteristics. The exhaust emissions and number concentration distributions of PM with particle sizes were also compared. Due to enhanced combustion characteristics, THC emissions decreased, whereas NOx emissions increased. Also, the number concentrations of PM, larger than 10 nm, also significantly decreased.

Effects of Ambient Conditions on the Atomization of Direct Injection Injector (분위기 조건이 직접분사식 인젝터의 미립화에 미치는 영향)

  • Lee, J.S.
    • Journal of ILASS-Korea
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    • v.6 no.1
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    • pp.25-34
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    • 2001
  • Several efforts to meet the exhaust gas regulation have been undertaken by many researchers in recent years. Main researches are on development of design techniques of intake port and combustion chamber, atomisation of fuel and precise control of air-fuel ratio, post-treatment of exhaust gas and so on. Engine technology is changed from PFI to GDI to correspond with exhaust gas regulation. GDI technique makes it possible to preserve lean air-fuel ratio and control accurate air-fuel ratio. Nevertheless, It is not cleared that information of spray characteristics and atomization process are very dependent on fluctuation of pressure and change of temperature in intake stroke. In this study, a constant volume combustion chamber is manufactured to investigate various fluctuations of in-cylinder pressure for injection duration. It is taken photographs of injection process of conventional GDI injector using PMAS. Then, it was verified experimently that ambient conditions as temperature and pressure of combustion chamber have effects on process of spray growth and atomization of fuel.

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