• Transactions of the Korean Society of Automotive Engineers
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• v.20 no.5
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• pp.130-137
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• 2012

Automotive engines need strategies to satisfy with the emission regulations in terms of PM and NOx. HC-LNT (Hydrocarbon-Lean NOx Trap) with secondary injection system is considered as more practical technology in order to cope with emission regulations. The HC-LNT system, which is using diesel fuel itself as a reducing agent, absorbs NOx in lean exhaust gas condition and releases NOx in rich exhaust gas conditions. In this system, inappropriate amounts of reducing agent will slip through the LNT without the profits of conversion and cause additional emission problems. Therefore, the suitable amount of reducing agent should be supplied into the catalytic converter. In this research, engine emission test was conducted to optimize injection quantity at the various engine test conditions. Different exhaust layouts and catalyst shapes have been studied and extension unit which makes better uniformity of exhaust gas was used for HC-LNT system. From this results, the effect of secondary injection conditions on NOx conversion characteristics of HC-LNT was clarified.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.15 no.12
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• pp.979-986
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• 2003

The performance characteristics of heating and cooling operation for a heat pump system using seawater heat source and exhaust energy are presented. The heat pump system is made of a waste heat recovery system and a vapor compression refrigeration system. The working fluid is R-22. The heat pump system COPs are measured during heating and cooling operation modes, and the resultant COPs were 9.7 and 7.9, respectively, which are three times higher than those of the heat pump itself. Therefore, the performance of the heat pump system using exhaust energy is excellent compared to that of a general heat pump. The experimental data can be effectively used for the design of the high efficient heat pump using a seawater heat source.

• Journal of Advanced Marine Engineering and Technology
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• v.31 no.7
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• pp.823-832
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• 2007

This paper presents the static characteristics of EGR-WI combined system. The water injection system was statically characterized by recording the engine exhaust outlet $NO_x$ emissions for comparison with baseline $NO_x$ emissions. Effects of the water injection system on CO and HC emissions and fuel consumption were examined. The research engine used for these experiments was a 103 kW turbocharged, intercooled, 2.5 L VM Motori CIDI engine equipped with a cooled EGR system. Water injection in the intake system demonstrated the potential for significant reductions in engine outlet $NO_x$ emissions. The system has reduced engine outlet $NO_x$ emissions by 40-50%, but caused significant increases in CO and HC emissions, particularly at low loads. Fuel consumption effects were minimal.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.5
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• pp.447-452
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• 2015

A hybrid power system was developed for agricultural machines with a 20kW output capacity, and it was attached to a multi-purpose cultivator to improve the performance of the cultivator. The hybrid system combined heterogeneous sources: an internal-combustion engine and an electric power motor. In addition, a power splitter was developed to simplify the power transmission structure. The cultivator using a hybrid system was designed to have increased fuel efficiency and output power and reduced exhaust gas emissions, while maintaining the functions of existing cultivators. The fuel consumption for driving the cultivator in the hybrid engine vehicle (HEV) mode was 341g/kWh, which was 36% less than the consumption in the engine (ENG) mode for the same load. The maximum power take off output of the hybrid power system was 12.7kW, which was 38% more than the output of the internal-combustion engine. In the HEV mode, harmful exhaust gas emissions were reduced; i.e., CO emissions were reduced by 36~41% and NOx emissions were reduced by 27~51% compared to the corresponding emissions in the ENG mode. The hybrid power system improved the fuel efficiency and reduced exhaust gas emissions in agricultural machinery. The hybrid system's lower exhaust gas emissions have considerable advantages in closed work environments such as crop production facilities. Therefore, agricultural machinery with less exhaust gas emissions should be commercialized.

• Journal of Advanced Marine Engineering and Technology
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• v.37 no.7
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• pp.694-700
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• 2013

The design of the exhaust manifold for the pulse converters of a 4 strokes high power medium-speed diesel engine is presented in terms of fatigue analysis. The said system undergoes thermal expansion due to high temperature of exhaust gas and is exposed to intrinsic vibration of the internal combustion engine. Moreover, the exhaust pulse generates pressure pulsating along the runner inside manifold. Under such circumstances, the design and construction of exhaust manifold must be carried out in a way to prevent early failure due to fracture. To validate the design concept, a test rig was developed to simulate the combination of thermal and vibrational movements, simultaneously. Experimental results showed that a certain sense of reliability can be achieved by considering a field factor obtained from the results of engine bench tests.

• Journal of Advanced Marine Engineering and Technology
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• v.31 no.8
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• pp.904-910
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• 2007

In this study an experimental research has been conducted to reduce NOx and smoke emission from diesel engine exhaust gas simultaneously by application of corona discharge type electrostatic precipitator(ESP). The ESP was installed between exhaust gas silencer and outlet terminal of exhaust gas system. The operating conditions as input parameters taken in this experiment were corona power input, gas velocity and equivalence ratio of gas. It was found that the corona discharge type ESP has notable effect on reducing smoke in exhaust gas but appeared to bring slight effect on reducing NOx.

• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.1
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• pp.139-145
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• 2007

This paper presents the low cycle thermal fatigue of the engine exhaust manifold subject to thermomechanical cyclic loadings. The analysis includes the FE model of the exhaust system, temperature dependent material properties, and thermal loadings. The result shows that at an elevated temperature, large compressive plastic deformations are generated, and at a cold condition, tensile stresses are remained in several critical zones of the exhaust manifold. From the repetitions of thermal shock cycles, plastic strain ranges could be estimated by the stabilized stress-strain hysteresis loops. The method was applied to assess the low cycle thermal fatigue for the engine exhaust manifold. It shows a good agreement between numerical and experimental results.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.661-665
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• 2005

The muffler reducing the exhaust noise and vibration from the engine influence on the engine performance. Recently the semi-active muffler was developed and adopted to the actual use in consideration of the cost and technical side for noise and vibration. This study is about the recently developed semi-active muffler. This paper attempt to analyze the dynamic stress field on the gate plate by using the finite element methods. According to the analysis of the Exhaust Variable Valve, its spring has the most influence on its operation compare with effects of other components. The design parameters of the Exhaust Variable Valve such as the spring displacement, diameter, coil number, free angle and so forth were used.

• Transactions of the Korean Society of Automotive Engineers
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• v.17 no.4
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• pp.24-31
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• 2009

This paper has been focused on the development of integrated automotive muffler system to meet getting more stringent sound quality target. Typically, muffler system consists of resonator and main muffler. The many varieties in exhaust pipe routing and the flexibility in muffler design make it possible to design an exhaust system to deliver tailpipe sound for specific sound quality requirement. In recent, it is strongly recommended that the function of resonator be merged into that of main muffler due to severe space limitation of underbody. The main objective of the paper is to study the effects of various geometrical parameters on the muffler performance. This work has succeeded in eliminating resonator without loss of muffler performance. This work has also investigated the effect of diameter of hole, geometries of pipes and location of muffler on the sound quality.

• Journal of Power System Engineering
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• v.17 no.4
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• pp.109-114
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• 2013

In this study, the microstructure, mechanical properties and high temperature oxidation characteristics of HiSiMo and HiSiMoM ductile iron for exhaust manifold were investigated. The HiSiMoM ductile iron was developed by optimization of alloying element addition and casting design. The exhaust manifold prototype was fabricated using the HiSiMoM iron and this resulted in the weight saving of 0.73kg. The microstructures of the HiSiMo and HiSiMoM irons were similar each other and graphite nodularity was 89% and 93% respectively. Tensile strengths of them were 663.5 and 674.4 MPa and Brinell hardness were 235.3 and 243.9 respectively. Both irons showed parabolic weight gain behavior in high temperature oxidation atmosphere. Oxidation layer was divided into external and internal layers. The weight gain of the HiSiMoM iron was lower than that of the HiSiMo iron after isothermal oxidation test at $900^{\circ}C$. This should be rationalized by higher Si enrichment at the interface of the matrix and internal layer of the HiSiMoM iron.