• Journal of Advanced Marine Engineering and Technology
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• 제21권3호
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• pp.302-310
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• 1997

In this paper, we find a method to improve ignitability using methanol which is prospective as an alternative fuel. The constant volume combuster is divided into main chamber and sub-cham¬ber. These two chambers are linked by an adapter which is shaped like a cup. We also compare CDI to HIS that is revised in our laboratory for making a scrutiny into the effects of ignition char¬acteristics. Besides, we analyze a flame propagation process in the main and sub-chamber through taking pictures 10, 000 frames per second by high speed camera at the state being fabricated quartz glass aside main and sub-chamber.

• Journal of Advanced Marine Engineering and Technology
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• 제17권4호
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• pp.11-19
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• 1993

The experimental study was carried out to investigate the stability and the performance characteristics of the aero-valved pulsating combustion system with maximum operating capacity of 60KW. The effect of geometry of combustion system on the stable condition, the flammability limit, the total pressure oscillation amplitude, and the operating frequency can be identified, and the maximum turn-down-ratio is obtained up to 3.3. The total pressure oscillation amplitude can be controlled by tunning the length of the air inlet pipe. The empirical equation with which the operating frequency can be approximated is proposed and the discrepancy is within 5%. The volumetric efficiency is identified to be one of the important parameters determining the upper flammability limit and the maximum value of which is approximately 22%.

• 한국자동차공학회논문집
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• 제22권3호
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• pp.148-156
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• 2014

This study is a follow-up study of "Development of Plasma Ignition System" was presented at the 2013 KSAE spring conference. This study compares lean limit of conventional ignition system with plasma ignition system on constant volume combustion test & Engine Combustion test.

• 한국자동차공학회논문집
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• 제4권3호
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• pp.220-231
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• 1996

In this research, we use IDI type constant volume combustion chamber which may make up stratified combustion to construct the design back data of lean-burn engine. Some experiments are conducted by the passagehole angle in the adapter of main chamber and sub-chamber. The effects on the combustion characteristics according to the ignition timing are investigated. The used fuel is methanol prospective for alternative fuel. Fuel is injected under 10.78MPa using solenoid and accumulator. As the results of the experiment, combustion characteristics reveals that ignition timing, passagehole angle and shape greatly effects on. Lean inflammability limit is extended to 0.45 in equivalence ratio.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2015년도 제51회 KOSCO SYMPOSIUM 초록집
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• pp.189-192
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• 2015

An experimental study was conducted to find the effect of DBD plasma on the flammability limits of inert-gas-diluted fuel. The results showed that the concentration of diluting nitrogen at flammability limit increased when nitrogen-diluted methane and propane were reformed by plasma, while it decreased when nitrogen-diluted ethylene was reformed by plasma. Gas chromatography results suggested that the fuel type dependence of flammability limits is due to the difference in the concentrations of hydrogen and hydrocarbon species in reformed fuel.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2015년도 제51회 KOSCO SYMPOSIUM 초록집
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• pp.245-246
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• 2015

In this study, the structure of a edge flame near the flammability limits was explored through several paths approaching the combustion limits of a non-premixed flame: i.e., increase of fuel dilution ratio (FDR), reduction of mean flow velocity and variation of gravity effect. As a result, a unique interesting flame structure was discovered; i.e., a diffusion flame branch was enclosed by two asymmetric premixed flame branches. These structures have been compared for various fuels. Conclusively, each fuel has different flame structure and the meaning of this structure was discussed concerned about our understanding of laminar flame structures.

• 한국자동차공학회논문집
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• 제23권6호
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• pp.650-655
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• 2015

A high energy ignition system is essential for lean burn or high EGR gasoline engine, which is getting more and more interest to improve fuel economy. The high energy ignition systems comprise plasma jet, laser beam, corona discharge and so on. In this study, a high energy ignition system using corona discharge is developed and tested in a constant volume combustion chamber. The developed system shows extension of lean limit of propane-air mixture and enhencement of combustion speed. Various shape of corona discharge plugs are also tested and compared in this study.

• 대한기계학회논문집B
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• 제20권1호
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• pp.359-368
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• 1996

For fuel economy and pollutant reduction, the interests in lean burn has increased recently. The purpose of this research is to develop a High Frequency Ignition System (HIS) that can make powerful ignition. We studied relations between performance of HIS and probability of inflammation under various ignition conditions. It is concluded that the portion of capacitance energy to the total energy is comparatively larger and that the optimum spark interval and spark duration are dependent upon conditions of Constant Volume Combustion Chamber.

• 한국분무공학회지
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• 제28권3호
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• pp.134-142
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• 2023

Electric field assisted combustion is a method that reduces instability in lean combustion. In this study investigated the effects of electrode position on propane-air flame characteristic using a ring electrode. Results showed that burning velocity was not affected by electrode position, but positive voltage expanded the flammability limit while negative voltage contracted it. The effect of voltage polarity on the flammability limit decreased as the electrode position increased. Expanding the flammability limit with a positive voltage can reduce NOx emissions.

• 한국분무공학회지
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• 제28권1호
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• pp.24-31
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• 2023

In this study, characteristics of a propane-air premixed flame sin DC electric field was investigated. The stainless steel Bunsen burner and the stainless steel ring were used as electrode, and the high voltage supply was used for applying electric field. Flammability range increased significantly when the positive voltage was applied because of extension of LBO limit, while it shrank when the negative voltage was applied. The reason for this was not much related to the burning velocity, but the induced flow around the burner by electric field. withNOx production slightly increased after positive voltage was applied in identical equivalence ratio. Nevertheless, it was advantageous to apply the positive electric field to reduce the NOx since the extension of LBO limit makes the burner possible to operate in very low equivalence ratio.