• Transactions of the Korean Society of Automotive Engineers
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• v.14 no.3
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• pp.10-21
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• 2006

The aim in this study is to develop the combined EGR system with a non-thermal plasma reactor for reducing exhaust emissions and improving fuel economy in turbo intercooler ECU common-rail diesel engines. At the first step, in this paper, the characteristics of performance and $NO_x{\cdot}THC$ emissions under four kinds of engine loads are experimentally investigated by using a four-cycle, four-cylinder, direct injection type, water-cooled turbo intercooler ECU common-rail diesel engine with a combined plasma exhaust gas recirculation(EGR) system operating at three kinds of engine speeds. The EGR system is used to reduce $NO_x$ emissions, and the non-thermal plasma reactor and turbo intercooler system are used to reduce THC emissions. The plasma system is a flat-to-flat type reactor operated by a plasma power supply. The fuel is sprayed by pilot and main injections at the variable injection timing between BTDC $15^{\circ}$ and ATDC $1^{\circ}$ according to experimental conditions. It is found that the specific fuel consumption rate with EGR is increased, but the fuel economy is better than that of mechanical injection type diesel engine as compared with the same output. Results show that $NO_x$ emissions are decreased, but THC emissions are increased, as the EGR rate is elevated. $NO_x$ and THC emissions are also slightly decreased as the applied electrical voltage of the non-thermal plasma reactor is elevated. Thus one can conclude that the influence of EGR in $NO_x$ and THC emissions is larger than that of the non-thermal plasma reactor, but THC emissions are greatly influenced by the non-thermal plasma reactor as the EGR rate is elevated.

• The Transactions of the Korean Institute of Power Electronics
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• v.8 no.4
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• pp.328-335
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• 2003

Test procedure for Electric Vehicle(EV) motor/controller has been developed. Most of existing standards mainly focus on minimum requirements for safe operation. However, detailed test procedures are not covered in the standard. In order to develop test items, methods and procedures which should be strictly applied to EV motor and controller, existing standards have been reviewed by the expert group in Korea. Based on their feedback, standard test procedure was proposed. Test procedure especially for combined motor and controller has been proposed. As a load lot the tested motor, M-G set, eddy current type engine dynamo and AC dynamo were used. Test procedures for the driving cycle test and regeneration test were proposed.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2012.05a
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• pp.586-591
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• 2012

The solution of maintenance decision support system for the gas turbine engine, which is currently operating in GUNSAN combined cycle power plant, was developed and is consist of online monitoring module, periodic performance trending module, optimal compressor washing interval analysis module and hot component management module. Also, GUI platform was applied to this solution for the user to monitoring the analyzed result of engine performance condition and then to make a decision of the consequent maintenance action. In online condition monitoring module, the performance degradation of engine is provided by the analysis of difference between the real time measurement data compared to exist engine performance. The optimal compressor washing interval module produced the washing interval of maximum net profit value by researching the maintenance expense and the loss profit value corresponds to the performance degradation with economic assessment algorithm. Thus, this solution support the user to enable the optimal maintenance and operation of gas turbine engine with overall analysis of engine condition and main information.

• Journal of Energy Engineering
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• v.18 no.4
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• pp.230-238
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• 2009

We study about small gas engine and fuel cell CHP (Combined Heat and Power) as the technologies for energy conservation and $CO_2$ emissions reduction. Korea government plans to use them in near future. This study quantitatively analyzed energy consumption and $CO_2$ emissions reduction potential of small CHP instead of existing electric power plant (coal steam, combined cycle and oil steam) using LEAP (Long-range Energy Alternative Planning system) as energy-economic model. Three future scenarios are discussed. In every scenario similar condition for each CHP is used. Alternative scenario I: about 6.34% reduction in $CO_2$ emissions is observed in 2019 due to increase in amount of gas engine CHP and fuel cell CHP while coal use in thermoelectric power plant is almost stagnant. In alternative scenario II: a small 0.8% increase in $CO_2$ emission is observed in 2019 keeping conditions similar to alternative scenario I but using natural gas in combined cycle power plant instead of coal. During alternative scenario II overall $CO_2$ emission reduction is observed in 2019 due to added heat production from CHP. Alternative scenario III: about 0.8% reduction in $CO_2$ emissions is observed in 2019 using similar CHP as AS I and AS II. Here coal and oil are used in thermoelectric power plant but the quantity of oil and coal is almost constant for next decade.

• Journal of the Korean Society of Propulsion Engineers
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• v.17 no.3
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• pp.56-66
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• 2013

Weight reduction of the VTHL / TSTO type of the reusable launch vehicles using RBCC engines are investigated. To predict weight and thrust of the vehicles, equations of motion are analyzed. Analysis results are compared with specifications of existing launch vehicles for validations. For the mission of inserting 2.5 ton payload to 200 km circular orbit, the case A, which uses the RBCC engine in the 1st stage shows smaller weight than the case B, which uses the RBCC engine in the 2nd stage. The weight of the case A shows only 25.8% of a existing rocket launch vehicle's weight.

• Journal of Advanced Marine Engineering and Technology
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• v.28 no.2
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• pp.315-331
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• 2004

The effects of intake mixture temperature on performance and exhaust emissions under four kinds of engine loads were experimentally investigated by using a four-cycle. four-cylinder. swirl chamber type. water-cooled diesel engine with scrubber EGR system operating at three kinds of engine speeds. The purpose of this study is to develop the scrubber exhaust gas Recirculation (EGR) control system for reducing $\textrm{NO}_{x}$ and soot emissions simultaneously in diesel engines. The EGR system is used to reduce $\textrm{NO}_{x}$ emissions. And a novel diesel soot-removal device of cylinder-type scrubber with five water injection nozzles is specially designed and manufactured to reduce soot contents in the recirculated exhaust gas to the intake system of the engine. The influences of cooled EGR and water injection. however. would be included within those of scrubber EGR system. In order to survey the effects of cooled EGR and moisture on $\textrm{NO}_{x}$ and soot emissions. the intake mixtures of fresh air and recirculated exhaust gas are heated up using a heater with five heating coils equipped in a steel drum. It is found that intake and exhaust oxygen concentrations are decreased, especially at higher loads. as EGR rate and intake mixture temperature are increased at the same conditions of engine speed and load. and that $\textrm{NO}_{x}$ emissions are decreased. while soot emissions are increased owing to the decrease in intake and exhaust oxygen concentrations and the increase in equivalence ratio. Thus ond can conclude that $\textrm{NO}_{x}$ and soot emissions are considerably influenced by the cooled EGR.

• Advances in aircraft and spacecraft science
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• v.5 no.4
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• pp.431-444
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• 2018

Numerical simulations have been conducted to study the unstart/restart characteristics of an over-under turbine-based combined-cycle propulsion system (TBCC) inlet during the inlet transition phase. A dual-solution area exists according to the Kantrowitz theory, in which the inlet states may be different even with the same input parameters. The entire transition process was divided into five stages and the unstart/restart hysteresis loop for each stage was also obtained. These loops construct a hysteresis surface which separates the operating space of the engine into three parts: in which a) inlet can maintain a started state; b) inlet keeps an unstarted state; c) inlet state depends on its initial state. During the transition, the operation of the engine follows a certain order with different backpressures and splitter angles, namely control route, which may result in disparate inlet states. Nine control routes with different backpressures and transition stages were designed to illuminate the route-dependent behavior of the inlet. The control routes operating towards the unstart boundary can make the inlet transit from a started state into an unstarted one. But operating backward the same route cannot make the inlet restart, additional effort should be made.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.04a
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• pp.168-171
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• 2007

A technical review of current slurry and gelled propellants is presented. In advanced countries, it is confirmed that these propellants have high specific impulse, density, excellent handling, safety characteristics and thrust controllability through research since 1950s. Substantial researches have been pursued to characterize the rheological properties, spray/combustion phenomena and propulsion system design for the gel propellant characteristics. Slurry and gelled propellants are developing actively to applicate both military and space propulsion fields such as tactical missile, air-breathing ramjet, pulse detonation engine, and combined cycle engine of future propulsion mode.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.705-708
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• 2011

Ejector system can induce the secondary flow or affect the secondary chamber pressure by both shear stress and pressure drop which are generated in the primary jet boundary. Ejectors are widely used in a range of applications such as a turbine-based combined-cycle propulsion system and a high altitude test facility for rocket engine, pressure recovery system, desalination plant and ejector ramjet etc. The primary interest of this study is to set up an design procedure on the configuration and operating condition of multi-ejector for the various high altitude simulation.

• Journal of the Korean Society of Propulsion Engineers
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• v.21 no.3
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• pp.91-100
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• 2017

The solution was developed for the maintenance decision support of combined cycle power plant gas turbine. The developed solution was applied to MHI501G gas turbine and is, in present, on the process of field test at GUNSAN combined cycle power plant, South Korea. The developed solution provides the calculated result of optimal overhaul maintenance period through following modules: Real Time Performance Monitoring, Model-Based Diagnostics, Performance Trend Analysis, Optimal Overhaul Maintenance Interval, Compressor Washing Period Management, and Blade Path Temperature Analysis. Model-Based Diagnostics module analyzed the differences between the data of gas turbine performance model and the online measurement. Compressor washing management module suggests the optimal point of balancing between the compressor performance and the maintenance cost.