• Journal of Ocean Engineering and Technology
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• v.13 no.3B
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• pp.38-46
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• 1999

Increasing stringent emissions legislation and requirement of more effective energy used for diesel engine demand the fine control of the fuel injection system. Recently, the electromagnetic fuel injection control system for diesel engine is tried to realize the optimum diesel combustion by the feel back sensing as optical signal of combustion flame. The photo detectors were made for the feed back signal of electromagnetic fuel injection control for small DI diesel engine. Their abilities to detect defining combustion events were examined. By evaluating test results, it was shown that the wider acceptable optical range design of optical probe window face, and selection of installation position and installation method of detector were important point for improving sensing ability. The detector was shown to detect start and end of diffused combustion and maximum point of flame intensity impossible for pressure sensor, and also shown that the maximum point of flame intensity was 75% of accumulated heat release point within the experimental conditions.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11b
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• pp.636-640
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• 2002

Acoustic coupled combustion instability, which is one of the most undesirable phenomena in the development of liquid propellant rocket engine, can cause serious damage to a rocket itself, and must be avoided by all means. Unfortunately, KSR-III rocket went through combustion instability during engine start at the propulsion test article No.2. To resolve the problem, time sequence (cyclogram) has been changed, and baffle system has been applied. In consequence of change, stable combustion was achieved.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.8
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• pp.813-820
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• 2015

Straight vegetable oil (SVO) is widely recommended as fuel for diesel engines in general and especially for marine diesel engines. However, SVOs used directly as fuel for diesel engines may cause problems for the engines; SVOs blended with diesel oil are a better choice. To widen understanding of the possibility of using blended SVOs as fuel alternatives, this paper presents results of experimental research on the combustion of blended straight vegetable oil in a marine diesel engine's cylinders. Results show that the fuel combustion process have the same curves as in simulations and, in the case of using blended fuels with up to 20% palm oil, the test diesel engine technical parameters such as engine output, exhaust gas temperatures, and specific fuel consumption are very similar to those of diesel oil (DO). Based on these results, marine diesel engines are strong potential applications and particularly recommended for the use of SVO blends.

• Journal of ILASS-Korea
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• v.22 no.4
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• pp.190-196
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• 2017

The aim of this work is to investigate the combustion and exhaust emission characteristics of low-temperature combustion (LTC) at various EGR test conditions using a single cylinder common-rail diesel engine. In high EGR rate combustion mode with DME fuel, 30% (${\Phi}=0.61$) and 50% (${\Phi}=0.86$) of EGR were respectively examined, and then the combustion, exhaust emissions, nano-particle characteristics of each cases were measured. From these results, it revealed that The ignition delay and combustion duration are prolonged as the increase of EGR rate. In addition, at an advanced injection timing (BTDC $30^{\circ}$), ignition delays were fairly increased because the dilution effect of EGR and also low charge in-cylinder temperature created a lean mixture, thus decreased the peak release rate.

• Clean Technology
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• v.12 no.2
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• pp.78-86
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• 2006

Computational analyses are conducted on the combustion characteristics of the coal- and the biomass-derived synthetic gases with low-Btu heating value in gas engine. Using thermochemical analyses on the synthetic gases, combustion pressure, temperature, exhaust gas composition, NO emission and engine power are predicted and the predicted results are compared with small-scale pilot engine test results. In order to investigate the unsteady combustion phenomena in gas engine combustion chamber, CFD analyses are carried out on the coal and the biomass synthetic gases and their computed results are compared to provide the guidelines for the design modification and the tuning of the gas engine burning the synthetic gases as alternative fuels.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.6
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• pp.37-43
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• 2003

The objective of this work is to investigate the effect of swirl, injection pressure and pilot injection on D.I. diesel combustion by using a transparent engine system. The test engine is equipped with common rail injection system to obtain high pressure and to control injection timing and duration. In this study, the combustion analysis and steady flow test were conducted to estimate the heat release rate from in-cylinder pressure. Soot distribution in diffusion flame according to swirl ratio, injection pressure and pilot injection was investigated by using LII technique. As the results, high injection pressure was found to shorten ignition delay as well as enhance peak pressure and heat release rate was greatly affected by injection timing and pilot injection. In addition, the results showed that the period of soot formation corresponded to the diffusion flame.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.04a
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• pp.109-112
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• 2011

The result of design review and arrangement of a combustion chamber test facility(CTF) and a turbo-pump real propellant test facility(TPTF) is briefly described. The development/qualification tests of combustion chamber and turbo-pump for 75ton-class liquid rocket engine will be performed in CTF and TPTF. The critical design of hydraulic-pneumatic system, control and data acquisition system, test stand cell, and auxiliary facilities in CTF and TPTF was performed.

• Journal of the Korean Institute of Gas
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• v.19 no.6
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• pp.22-27
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• 2015

Hydrogen features highest energy density per mass and is expected to be desirable as a fuel of HALE(High altitude long endurance) UAV(Unmanned aerial vehicle). A reciprocating internal combustion engine is known to be a reliable and economic power source for this kind of UAV. Therefore, the combination of hydrogen and engine is worth of doing research. Test bench with 2.4L Spark-Ignited engine was prepared for the experiment in which start and combustion characteristics at idle condition were examined in this study. Stable hydrogen supply system and a universal ECU(Engine control unit) were also utilized for the test engine. Equivalence ratio and spark timings at idle operation were investigated and compared to the data of gasoline engine. The results will be a starting point for full-scale research of hydrogen engine for HALE UAV.

• Journal of the Korean Society of Combustion
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• v.22 no.1
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• pp.46-52
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• 2017

High-frequency combustion instabilities may occur during the development of feasible engine combustors. These instabilities can result in irreparable damages to the wall of combustors or the degradation of engine performance. So, it is essential to identify injectors that have high stability characteristics during the early stages of development. The objective of present study was to assess the stability of coaxial injectors and an impinging injector with different recess lengths in order to develop stable injectors optimally. Stability margin was evaluated based on the distance from operating condition to the unstable regions. A simulating combustion test method was used to analyze the stability of injectors. A small-scale combustion chamber was designed to simulate the first tangential acoustic mode of the actual combustor. Gaseous oxygen and a mixture of methane and propane were used as simulant propellants to satisfy their flow similarity to the actual propellants of a combustor in a liquid rocket combustor. The results indicated that injectors having small recess lengths showed relatively large combustion stability margins. For the injectors of large recess lengths, instability regions with large and super-large amplitude oscillations were observed. Thus, injector with shorter recess lengths had a higher stability than that of longer one due to the different mixing processes.

• Journal of the Korean Society of Propulsion Engineers
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• v.22 no.1
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• pp.52-57
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• 2018

This paper presents the design and cold flow test results of oxidizer-rich preburner injectors for a 9 tonf-class staged combustion engine cycle. Three types of coaxial swirl injectors were designed, and 12 injectors were designed for each type. The diameters of the fuel tangential holes are identical. The diameters of the oxidizer tangential holes were varied to investigate the influence of combustion in the oxidizer-rich preburner according to the momentum ratio of the gas oxidizer generated from combustion in the injector chamber and liquid oxidizer through the cooling channel. It will be verified through a powerpack and combustion test using an oxidizer-rich preburner. In the cold flow test, the fuel flow rate and oxidizer tangential hole flow rate reached the target value based on the designed differential pressure.