• Transactions of the Korean Society of Automotive Engineers
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• v.20 no.3
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• pp.106-112
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• 2012

Since air pollution problem by emissions from automotive vehicles has become social issues, lean-burn gasoline direct injection (GDI) engine is focused as an alternative to meet the requirement of reinforced emission regulation and improved fuel consumption. Spray-guided type DI combustion is promising technology, which characterized by the centrally mounted injector and closely positioned spark plug, since stable lean combustion can be realized even at ultra-lean mixture condition. In the present study, the effect of multi-ignition with developed charge coil on combustion and emission characteristics was investigated in optical accessible single cylinder engine. In order to fully understand the in-cylinder phenomena and the mechanisms of emission production, optical diagnostics, such as flame visualization was also carried out at frequently using operating condition. Multi-ignition is effective to improve fuel economy but increase NOx emission at flammability limit.

• Journal of Energy Engineering
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• v.22 no.2
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• pp.169-174
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• 2013

An experimental study has been conducted for the design of the regenerative oxy-fuel combustion system with ceramic ball. Various design parameters are considered such as ball size, regenerator weight, and combustion load. Regenerative system with a pair of oxygen burners and regenerators is set up and the temperature of oxygen and exhaust gas passing through ball regenerator is measured. It is shown that the temperature distributions with time are affected by ball diameter and regenerator weight, and the significant temperature change is observed by combustion load. As the ball size decreases and the regenerator weight increases, the regenerating temperature efficiency increases. It is found that the heat recovery ratio is low despites of high regeneration temperature efficiency.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.484-488
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• 2010

In this study, combustion experiments of the End-Burning Hybrid Propulsion System using $GN_2O$(Gas Nitrous oxide)/HDPE were performed and the results were compared to those of the combustion experiments using GOX/HDPE. The regression rate of the solid fuel using $GN_2O$ is lower than that of the solid fuel using GOX since oxidizer inlet velocity of $GN_2O$ is lower than that of GOX. However, in case of using $GN_2O$, the characteristic velocity is higher than those of the GOX. The combustion chamber pressure and thrust were relatively kept constant during combustion.

• International Journal of Precision Engineering and Manufacturing
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• v.3 no.2
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• pp.45-51
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• 2002

Recently the interest for the environment is increasing. So the criterion for the evaluation of the burner has changed. For efficient driving problem, if the thermal efficiency is higher and the oxygen in exhaust gas is lower, then burner is evaluated better. For environmental problem. burner must satisfy NOx limit, soot limit and CO limit. Generally the experienced operator judge of the combustion status of the burner by the color of flame. we don't still have any satisfactory solution against it. the relation of the combustion status and the color of the flame hasn't still been established. This paper is the study about the relation of the combustion status and the color of the flame. This paper describes development of real time flame diagnosis technique that evaluate and diagnose combustion state such as consistency of components in exhaust gas, stability of flame in quantitative sense. In this paper, it was proposed on the flame diagnosis technique of burner using image processing algorithm, the parameter extracted from the image of the flame was used as the input variables of the flame diagnostic system. at first, linear regression algorithm and multiple regression algorithm was used to obtain linear multi-nominal expression. Using the constructed inference algorithm, the amount of NOx and CO of the combustion gas was successfully inferred. the combustion control system will be realized sooner or later.

• Journal of the Society of Disaster Information
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• v.16 no.2
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• pp.383-391
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• 2020

Purpose: To identify internal self ignition and ignition caused by external flames in energy storage rooms, and to analyze the difference between ignition due to overheating and ignition caused by external heat sources. Method: membrane melting point measurement, battery external hydrothermal experiment, battery overcharge experiment, comparative analysis of electrode plate during combustion by overcharge and external heat, overcharge combustion characteristics, external hydrothermal fire combustion characteristics, 3.4 (electrode plate comparison) / 3.5 (overcharge) /3.6 (external sequence) analysis experiment. Result: Since the temperature difference was very different depending on the position of the sensor until the fire occurred, it is judged that two temperature sensors per module are not enough to prevent the fire through temperature control in advance. Conclusion: The short circuit acts as an ignition source and ignites the mixed gas, causing a gas explosion. The electrode breaks finely due to the explosion pressure, and the powder-like lithium oxide is sparked like a firecracker by the flame reaction.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.432-437
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• 2010

A new device injecting secondary fuel behind flameholder was invented and tested in order to reduce low frequency combustion instability of combustor using V-gutter flameholder. Specially designed combustion device could make large combustion instability up to 180 dB successfully, and newly invented device made a success to reduce 110~120Hz low frequency pressure pulsation up to 84%. It was found that the fuel flow rate of secondary fuel supplying behind flameholder was the only parameter which dominates reduction of instability. It is considered that stabilized flame with sufficient secondary fuel can lead to break the connection between combustion system and acoustic system due to independence of flame from fluctuation of main fuel resulted from synchronization with acoustic wave.

• Journal of Aerospace System Engineering
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• v.15 no.3
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• pp.79-86
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• 2021

For a preliminary study on a thrust-throttleable Variable Flow Ducted Rocket, a gas generator and flow control valve were developed, and ground combustion tests were performed. The gas generator and flow control valve operated at the required performance level for parameters, such as heat-resistance, combustion-time, pressure, and temperature. The combustion characteristics of a fuel-rich solid propellant mixed with Boron/MgAl/AP, etc., were also analyzed. A Plunger-type flow control valve was designed to control the discharge flow area, and it was confirmed that the flow control valve was able to control the combustion gas flow rate and pressure. However, due to the reduction of the discharge flow area caused by adhesion of combustion products, the combustion pressure continuously increased. The analysis of the pressure increase is covered in Part 2 of this paper.

• 한국연소학회:학술대회논문집
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• 2004.11a
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• pp.206-212
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• 2004

It is necessary to consider the stability, economic environmental-friendly problems by the development of the road, supply of the automobile, environmental problem as designing the exhaust system. To reduce the noise and the vibration of the automobile, it is needed to consider the pulsation noise, air current noise, vibration of air pipe which generate the intake and exhaust noise of the automobile. Moreover, the discharge sounds, intake sound, radiation sound, transmitted sound are occurred. To reduce this influence, the variable valve is needed and to control these factors, path transformation muffler and active type muffler are needed. While engine efficiency could be reduced with this transformationand resistance by the pressure, thermal property. In this study, how to design exhaust systems yielding higher condversion efficiency, lower backpressure and optimize the performance. this study is recommended for exhaust system and designers and engineers involved in SI engine exhaust system and it will furnish information for you to design more efficient.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.1686-1691
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• 2004

The effect of recirculated exhaust gas on performance and exhaust emissions with FGR rate are investigated by using a natural circulation, pressurized draft and water tube boiler with FGR system operating at several boiler loads and over fire air(OFA) damper openings. The purpose of this study is to apply the FGR system to a power plant boiler for reducing $NO_{x}$ emissions. To activate the combustion, the suction damper of two stage combustion system installed in the upper side of wind box is opened by handling the lever between $0^{\circ}$ and $90^{\circ}$ , and the OFA with 0 to 20% into the flame is supplied, as the combustion air supplied to burner is reduced. It is found that the fuel consumption rate divided by evaporation rate does not show an obvious tendency to increase or decrease with rising the FOR rate, and $NO_{x}$ emissions are decreased, at the same OF A damper opening, as FOR rates are elevated and boiler loads are dropped.

• Journal of Advanced Marine Engineering and Technology
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• v.22 no.2
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• pp.248-256
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• 1998

The effects of fuel injection system on the performance in a V8-type diesel engine was stuided in this paper. Fuel injection system is important factor which influence the engine performance and exhaust emission bcasuse the properties in the injected fuel depend on the atomization characteristics. In this study using diesel engine of 17.7:1 compression ration the engine performance and exhaust emission are measured experimentally according to 1000, 1400, 2200rpm in the full-load conditions. The chosen parameters for the major system are such diameter shape of combustion chamber and intake system. The results are as follows: As the nozzle hole diameter and injection angle become smaller and as the injection timing gets advanced the fuel consumption and concentration of smoke are decreasing whereas concentration of $NO_{x}$ is increasing. Andconcentration of $NO_{x}$ is increasing in accordance with the increase of injection pipe diameter and nozzle protrusion. Also it is shown that re-entrant type combustion chamber is more effective than that of toroidal type in the improvement of $NO_{x}$ reduction.