• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.28 no.1
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• pp.45-52
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• 1992

In this paper, combustion characteristics and engine performance varying with blending rate of fish oil using five test fuels, e.g.pure diesel oil and four types of sardine-oil-blended diesel oils, their blending rates by weight being 20%, 40%, 60% and 80% respectively, and operating condition of engine, were investigated experimentally both in the constant volume combustion bomb and in the engine. The results are summarized as follows: 1) In the bomb, the influence of temperature on ignition delay of sardine-oil-blended diesel oils was larger than that of pure diesel oil, and it tended to increase as the blending rate of fish oil increase sardine-oil-blended diesel oils. As far as the influence of pressure on ignition delay concerns, there was no significant difference with all the test fuels. 2) In the engine, the ignition delay of fish-oil- blended diesel oils was longer than that of pure diesel oil, and it tended to increase as the blending rate increases. In the bomb, the ignition delay in high temperature showed no significant difference between with pure diesel oil and with fish-oil-blended diesel oils, and it was especially short with 60% fish-oil-blended diesel oil. In low temperature, however, the delay became longer as the blending rate increase. 3) The combustion duration was shorter with fish-oil-blended diesel oils than with pure diesel oil and it became a little shorter as the blending rate increases. 4) The rate of fuel consumption showed no significant difference between with fish-oil-blended diesel oils and with prue diesel oil, although calorific value of fish oil was lower than that of diesel oil. 5) Smoke density in exhaust gas was lower with fish-oil-blended diesel oils than with pure diesel oil and the higher the blending rate was, the lower the smoke density became.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.1
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• pp.17-24
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• 2004

As the environmental pollution becomes serious global problem, the regulation of emission exhausted from automobiles is strengthened. Therefore, it is very important to know how to reduce the NOx and PM simultaneously in diesel engines, which has lot of merits such as high thermal efficiency, low fuel consumption and durability. By this reason, the new concept called as Homogeneous Charge Compression Ignition(HCCI) engines are spotlighted because this concept reduced NOx and P.M. simultaneously. However, it is well known that HCCI engines increased HC and CO. Thus, the investigation of combustion characteristics which consists cool and hot flames for HCCI engines were needed to obtain the optimal combustion condition. In this study, combustion characteristics for direct injection type HCCI engine such as quantity of cool flame and hot flame, ignition timing and ignition delay were investigated to clarify the effects of these parameters on performance. The results revealed that diesel combustion showed the two-stage ignition of cool flame and hot flame, the rate of cool flame increase and hot flame decrease with increasing intake air temperature. On the other hand, the gasoline combustion is the single-stage ignition and ignition timing is near the TDC. In addition mixed fuel combustion showed different phenomenon, which depends on the ratio of gasoline component. Ignition timing of mixed fuel is retarded near the TDC and the ignition delay is increased according to ratio of gasoline.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.7
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• pp.721-727
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• 2010

The spontaneous ignition of coal stockpile causes serious safety and economic problems. Such spontaneous ignition occurs in coal stockpile when the rate of heat released by the oxidation of coal is greater than the rate of heat lost to the surroundings. In this study, a two-dimensional unsteady model is adopted for studying spontaneous ignition and the numerical results are compared with experimental results. The numerical results are in a good agreement with the experimental ones. Depending on the porosity, the internal maximum temperature, pressure, and oxygen mass fraction during spontaneous ignition are investigated. On the basis of the numerical results, the transient temperature variations for several shapes of coal stockpiles are analyzed. Further, the physical mechanisms of hot-spot formation and spontaneous ignition are analyzed.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.03a
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• pp.593-596
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• 2004

We are developing a micro-solid propellant rocket array thruster for simple attitude control of a 10 kg class micro-spacecraft. The prototype has ø 0.8 mm solid propellant micro-rockets arrayed at a pitch of 1.2 mm on a 22 x 22 mm substrate. In previous studies, an impulse thrust of 4.6 x 10$^{-4}$ Ns was obtained in vacuum, but we found the problems of unacceptably low ignition success rate and incomplete combustion. This paper describes experiments to improve the ignition rate. In order to achieve this goal, we tried to solidify paste-like ignition aid (RK) on the ignition heaters with strong adhesion. To make the paste-like RK, isoamyl acetate was added to RK powder. We tested 9 rockets, but only 2 rockets were ignited with huge ignition energy. This is because the heat con-duction between the ignition heater and the RK was too low to ignite the RK, since dried RK had a lot of pores. Also, a large cavity was sometimes found just above the ignition heater.

• Journal of the Korean Institute of Gas
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• v.11 no.2 s.35
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• pp.10-14
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• 2007

Flash point is one of the major physical properties used to evaluate fire hazards of the combustible liquids. Properties showing relative fire hazards of the combustible liquids are heat release rate(HRR), peak heat release rate(PHRR), time to ignition(TTI), mass loss rate, and yield of $CO/CO_2$. The relationships between flash points and fire properties of the combustible liquids were examined in this study. For this study, mass loss rate and time to ignition were measured to calculate fire properties of the combustible liquids. The results showed that good correlations could be found between flash point and time to ignition, time to peak heat release rate, and the propensity to flashover. From a presented results, the parameters can be used to evaluate relative hazards of the combustible liquids on fire.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.2
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• pp.83-90
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• 2004

A flywheel-driven rapid compression and expansion machine is developed and utilized for experimental study of homogeneous charge compression ignition combustion. Compression ignition of homogeneous charge in IC engines offers possibilities of realizing ultra-lean engine operation with greatly reduced NOx and particulate formation. Fundamental investigations are carried out in order to better understand this ideal engine combustion mechanism. Perfectly premixed propane-air mixtures of various equivalence ratio are compression-ignited in the rapid compression and expansion machine, and the characteristics of the auto-ignition and the following combustion process are analyzed.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.28 no.3
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• pp.324-329
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• 2004

As a new concept in engines and a power source for future automotive applications, the HCCI(Homogeneous Charge Compression Ignition) engine has been introduced. Essentially a combination of spark ignition and compression ignition engines, the HCCI engine exhibits low NO$_x$ and PM emissions as well as high efficiency under part load. In this research, a 4 cylinder diesel engine was converted into a HCCI engine, and propane was used as the fuel. The main parameters for this research are fuel flow rate and the temperature of the intake manifold, and the effects of such on a HCCI engine's performance and exhaust was investigated.

• Journal of Energy Engineering
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• v.14 no.4 s.44
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• pp.226-231
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• 2005

Essentially combination of spark ignition and compression ignition engines, the HCCI engine exhibits low NOx and Particulate Matter (PM) emissions as well as high efficiency under part load. This paper is concerned with the Homogeneous Charge Compression Ignition (HCCI) engine as a new concept in engines and a power source for future automotive applications. In this research, a 4 cylinder diesel engine was converted into a HCCI engine, and propane was used as the fuel. The purpose of this research is to show the effects of fuel flow rate and the temperature of the intake manifold on the performance and exhaust of an HCCI engine.

• Journal of ILASS-Korea
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• v.16 no.1
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• pp.51-57
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• 2011

An experimental study was performed to explore characteristics of combustion and exhaust emissions in the compression ignition engine of RCCI (reactivity controlled compression ignition) using diesel-gasoline dual fuel. A dual-fuel reactivity controlled compression ignition concepts is demonstrated as a promising method to achieve high thermal efficiency and low emissions. For investigating combustion characteristics, engine experiments were performed in a light-duty diesel engine over a range of SOIs (start of injection) and gasoline percents. The experimental results showed that cases of diesel-gasoline dual fuel combustion is capable of operating over a middle range of engine loads with lower levels of NOx and soot, acceptable pressure rise rate, low ISFC (indicated specific fuel consumption), and high indicated thermal efficiency.

• Journal of ILASS-Korea
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• v.5 no.4
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• pp.66-71
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• 2000

The present study is mainly motivated to investigate the vaporization, auto-ignition and combustion processes in the high-pressure engine conditions. The high-pressure vaporization model is developed to realistically simulate the spray dynamics and vaporization characteristics in high-pressure and high-temperature environment. The interaction between chemistry and turbulence is treated by employing the Representative Interactive Flamelet (RIF) Model. The detailed chemistry of 114 elementary steps and 44 chemical species is adopted for the n-heptane/air reaction. In order to account for the spatial inhomogeneity of the scalar dissipation rate, the multiple RIFs are introduced. Numerical results indicate that the RIF approach together with the high-pressure vaporization model successfully predicts the ignition delay time and location as well as the essential features of a spray ignition and combustion processes.