• Title/Summary/Keyword: Spark-ignited Direct Injection

Search Result 13, Processing Time 0.02 seconds

A Study on Ignition Probability and Combustion Characteristics of Low Pressure Direct Injection LPG according to a Function of Ambient Condition (분위기 조건 변화에 따른 저압 직접분사식 LPG의 점화성 및 연소특성 연구)

  • Chung, Sung-Sik;Hwang, Seong-Ill;Yeom, Jeong-Kuk;Jeon, Byong-Yeul
    • Journal of Power System Engineering
    • /
    • v.20 no.2
    • /
    • pp.32-42
    • /
    • 2016
  • Under part load condition of spark-ignition engine, pumping loss had great effect on engine efficiency. To reduce pumping loss, the study designed spark-ignited engines to make direct spray of gasoline to combustion chamber. In spark-ignited direct-injection engines, ignition probability is important for successful combustion and flame propagation characteristics are also different from pre-mixed combustion. This study designed a visualization testing device to study ignition probability of spark-ignited direct-injection LPG fuel and combustion flame characteristics. This visualization device consists of combustion chamber, fuel supply system, air supply system, electronic control system and data acquisition system. Ambient pressure, ambient temperature and ambient air flow velocity are important parameters on ignition probability of LPG-air mixture and flame propagation characteristics, and the study also found that sprayed LPG fuel can be directly ignited by spark-plug under proper ambient conditions. To all successful cases of ignition, the study recorded flame propagation image in digital method through ICCD camera and its flame propagation characteristics were analyzed.

A Study on Characteristics of Spray and Combustion of LPG and CNG about the Effect of Impingement-wall under Direct Injection Condition (직접분사 조건에서 충돌벽면이 미치는 영향에 대한 LPG와 CNG의 분무 및 연소 특성 연구)

  • Chung, Sung-Sik;Hwang, Seong-Ill;Yeom, Jeong-Kuk;Kim, Sung-Hee
    • Journal of Power System Engineering
    • /
    • v.19 no.4
    • /
    • pp.56-68
    • /
    • 2015
  • Liquefied petroleum gas and compressed natural gas haven been regarded as promising alternative fuels because of no smoke, and they are also clean fuel for spark-ignited engine. In spark-ignited direct-injection engine, direct injection technology can increase engine volumetric efficiency significantly and also reduce necessity of throttle valve. This study designed combustion chamber equipped with visualization system. To improve ignition probability, the study designed to help three types of impingement-walls to form mixture. In doing so, LPG CNG-air mixture could be easily formed after spray-wall impingement and ignition probability increased too. The results of this study could contribute as basic resources of spark-ignited direct injection LPG and CNG engine design and optimization extensively.

Analysis of Spray and Flow Fields for Development of Spark-ignited Direct Injection Engine (가솔린 직분식 엔진의 연소실 개발을 위한 분무 및 유동장 해석)

  • Choi, K.H.;Park, J.H.;Lee, N.H.
    • Transactions of the Korean Society of Automotive Engineers
    • /
    • v.6 no.6
    • /
    • pp.202-209
    • /
    • 1998
  • For development of SDI(Spark-ignited Direct Injection) engine, stratified mixture formation with adequate strength at spark plug was required in wide range of engine operating conditions. So, spray structure under high ambient pressure and spray distribution after impingement on piston bowl in motoring engine was visualized by using laser equipments. Also, incylinder bulk flow structure was measured by using PIV (Paiticle Image Velocimetry) system. Counter-rotating tumble port and bowl piston was found effective to conserve bulk motion directed to spark plug in compression stroke. In addition, mask attached near valve seat in intake port was proposed to attenuate conventional tumble component and enhance counter-rotating tumble component.

  • PDF

An Experimental Study on the Ignition Probability and Combustion Flame Characteristics of Spark-Ignited Direct-Injection CNG (스파크점화직분식 CNG의 점화성 및 연소화염 특성에 대한 연구)

  • Hwang, Seongill;Chung, Sungsik;Yeom, Jeongkuk;Jeon, Byongyeul;Lee, Jinhyun
    • Journal of ILASS-Korea
    • /
    • v.21 no.1
    • /
    • pp.37-46
    • /
    • 2016
  • For the SI engines, at only full load, the pumping loss has a negligible effect, while at part load conditions, the pumping loss increases. To avoid the pumping loss, the spark-ignited engines are designed to inject gasoline directly into the combustion chamber. In the spark-ignited direct-injection engines, ignition probability is important for successful combustion and the flame propagation characteristics are also different from that of pre-mixed combustion. In this paper, a visualization experiment system is designed to study the ignition probability and combustion flame characteristics of spark-ignited direct-injection CNG fuel. The visualization system is composed of a combustion chamber, fuel supply system, air supply system, electronic control system and data acquisition system. It is found that ambient pressure, ambient temperature and ambient air flow velocity are important parameters which affect the ignition probability of CNG-air mixture and flame propagation characteristics and the injected CNG fuel can be ignited directly by a spark-plug under proper ambient conditions. For all cases of successful ignition, the flame propagation images were digitally recorded with an intensified CCD camera and the flame propagation characteristics were analyzed.

An Study on Spray and Combustion Characteristics of Direct Injection LPG under Low Pressure Injection Condition (저압 분사조건에 따른 직접분사 LPG의 분무 및 연소특성 연구)

  • Hwang, Seong-Ill;Chung, Sung-Sik;Yeom, Jeong-Kuk;Lee, Jin-Hyun
    • Journal of the Korean Institute of Gas
    • /
    • v.20 no.1
    • /
    • pp.52-61
    • /
    • 2016
  • Liquefied petroleum gas is regarded as a promising alternative fuel as it is eco-friendly, has good energy efficiency and output performance, practically and has high cost competitiveness over competing fuels. In spark-ignition engine, direct injection technology improves engine volumetric efficiency apparently and operates engine using the stratified charge that has relatively higher combustion efficiency. This study designed a combustion chamber equipped with visualization system by applying gasoline direct injection engine principle. In doing so, the study recorded and analyzed ignition probability and flame propagation process of spark-ignited direct injection LPG in a digital way. The result can contribute as a basic resource widespread for spark-ignited direct injection LPG engine design and optimization extensively.

A Experimental Study on the Effects of the Impingement-wall on the Spray and Combustion Characteristics of Direct-Injection LPG (충돌벽면이 직분식 LPG의 분무 및 연소 특성에 미치는 영향에 관한 실험 연구)

  • Hwang, Seong-Ill;Chung, Sung-Sik;Yeom, Jeong-Kuk
    • Journal of Power System Engineering
    • /
    • v.19 no.2
    • /
    • pp.49-56
    • /
    • 2015
  • As an alternative fuel that can be used in SI engine, LPG is one of clean fuels with larger H/C ratio compared to gasoline, low $CO_2$ emission, and small amount of pollutants such as sulfur compounds. When LPG is used in spark ignition engine, volumetric efficiency of the engine can be improved and pumping loss can be reduced by performing direct injection into the combustion chamber instead of port fuel injection. LPG-DI engine allows for lean combustion and stratified combustion under low load. In case of stratified combustion, air fuel ratio can be greatly increased compared to theoretic mixture ratio combustion. Improved thermal efficiency of the engine and reduced pumping loss can be expected from stratified combustion. Accordingly in this study, an experimental apparatus for visualization was designed and manufactured to study the combustion process of LPG after injection and ignition, intended to examine ignition probability and combustion characteristics of spark ignition direct injection(SIDI) LPG fuel. Ambient pressure, ambient temperature and fuel injection pressure were found as important variables that affect ignition probability and flame propagation characteristics of LPG-air mixture. Also, it was verified that the injected LPG fuel can be directly ignited by spark plug under appropriate ambient conditions.

In-Cylinder Flow Analysis in a Spark-ignited Direct Injection Engine using CFD (CFD를 이용한 직접 분사식 스파크 점화 엔진의 실린더 내부 유동 해석)

  • 김명환;이내현;최규훈
    • Transactions of the Korean Society of Automotive Engineers
    • /
    • v.7 no.5
    • /
    • pp.22-30
    • /
    • 1999
  • Optimization of in-cylinder flow is regarded as one of the most important factors to realize stable stratified charge combustion in a Spark-ignited Direct Injection(SDI) engine. Therefore, Computational Fluid Dynamic(CFD) simulation technique were used to clarify the characteristics of in-cylinder flow of a SDI engine with top entry intake port. Also, CFD results were compared to experimental results using Laser Doppler Velocimetry(LDV), Particle Image Velocimetry(PIV) and good validations were met. As the results reverse tumble flow generated during intake process was preserved by configuration of curved piston while base and reverse tumbles were diminished at the end of compression stroke in case of flat top piston. In addition, it will be needed to optimize the fuel mixture distribution based on these results.

  • PDF

A Study on the Spray and Combustion Characteristics of Direct-injection LPG (직접분사식 LPG의 분무 및 연소 특성에 관한 연구)

  • Hwang, Seong-Ill;Chung, Sung-Sik;Yeom, Jeong-Kuk
    • Journal of Power System Engineering
    • /
    • v.19 no.2
    • /
    • pp.40-48
    • /
    • 2015
  • As advantages of LPG-DI engine, LPG is directly injected into combustion chamber during compression stroke to reduce compression temperature, prevent knock and spontaneous combustion, and adjust engine output using the amount of directly injected fuel, thereby reducing pumping loss caused by throttle valve. Stratified charge can be supplied nearby spark plugs to allow for overall lean combustion, which improves thermal efficiency and can cope with problems regarding emission regulations. In addition, it is characterized by free designing of intake manifold. Despite the fact that LPG-DI has many advantages as described above, there is lack of detailed investigation and study on spray characteristics, combustion flame characteristics, and ignition probability. In this study, a visualization experiment system that consists of visualization combustion chamber, air supply control system, emission control system, LPG fuel supply system, electronic control system and image data acquisition system was designed and manufactured. For supply of stratified charge in the combustion chamber, alignment of injector and spark plugs was made linear.

Quasidimensional Simulation with Multi-zone Combustion Model for Homogeneous GDI Engine Emissions and Knocking (균일혼합기 가솔린 직분사 엔진의 다중 영역 유사차원 해석을 통한 배기 및 노킹 예측)

  • Lee, Jaeseo;Huh, Kang Y.;Kwon, Hyuckmo;Park, Jae In
    • Journal of the Korean Society of Combustion
    • /
    • v.18 no.1
    • /
    • pp.7-12
    • /
    • 2013
  • A quasidimensional program is developed for a four stroke cycle homogeneous GDI (Gasoline Direct Injection) engine. It includes models for spray, burning rate and chemistry to predict knock and emissions. With early injection a homogeneous GDI engine goes through spark ignited, turbulent premixed combustion as in PFI (Port Fuel Injection) engines. The cylinder charge is divided into unburned and burned zone with the latter divided into multiple zones of equal mass to resolve temperature stratification. Validation is performed against measured pressure traces, NOx and CO emissions at different load and RPM conditions. Comparison is made between an empirical knock model and predictions by the chemistry model in this work.