• Transactions of the Korean Society of Automotive Engineers
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• v.18 no.5
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• pp.124-129
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• 2010

The direct injection (DI) diesel engine has become a prime candidate for future transportation needs because of its high thermal efficiency. However, nitrogen oxides (NOx) increase in the local high temperature regions and particulate matter (PM) increases in the diffusion flame region within diesel combustion. Therefore, the demand for developing hybrid system consist of exhaust gas recirculation (EGR) and aftertreatment system as well as diesel particulate filter (DPF) or lean NOx trap (LNT) should be applied. The variation of EGR rate due to the malfunction of EGR valve can affect not only the combustion stability of engine but also the performance of aftertreatment system. In this research, 2.0 liter 4-cylinder turbocharged diesel engine was used to investigate the combustion and emission characteristics for various operating conditions with EGR. While the fuel consumption was increased with increase of EGR rate, NOx emission was improved by maximum 90% at low speed, low load operating condition. To achieve combustion stability and reliability of aftertrearment system with minimum penalty in fuel consumption and emissions, the fault diagnosis of EGR malfunction must be employed.

• 유체기계공업학회:학술대회논문집
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• 2005.12a
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• pp.796-802
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• 2005

Numerical analysis has been conducted for improving air flow characteristics in the exhaust aftertreatment system of diesel-fueled passenger cars by changing axial length and cone shape of a DPF diffuser. The results of air velocity and static pressure distributions along with air flow uniformity results suggest that a diffuser shape with 2D or 3D function type is better for air flow patterns in front of a DPF.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.3
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• pp.163-170
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• 2016

Regulations for the exhaust gas of diesel vehicles are being strengthened every year. Recently, diesel emission regulations for HC, CO, NOx, and particulate matter (PM) have been subject to very strict standards. In the future, the regulation of PM is expected to become stricter. Accordingly, diesel particulate filters (DPFs) have been applied to most diesel vehicles for PM reduction. With increasing engine mileage, ash and soot from the engine exhaust gas accumulate inside the DPF. This accumulation can damage the DPF or degrade engine performance. Therefore, efficient cleaning of the DPF is critical for the maintenance of the engine. If the DPF is well managed through regular cleaning, it can improve the power and fuel economy of the engine and reduce maintenance costs. Therefore, this study was performed to develop a high-efficiency cleaning method for DPFs and an apparatus that can more effectively clean out the accumulated ash and soot.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.83-83
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• 2010

산업이 고도화되는 과정에서 에너지의 고효율화를 위하여 고온, 고압 등의 극한환경 하의 공정이 불가결하며, 이에 따라 초미세분진인 나노 입자가 증가되고 있다. 이에 따라 해당 나노의 입자 처리를 위하여 다양한 용도에서의 고온 필터가 산업적으로 요구되고 있다. 본 연구에서는 디젤엔진 매연저감 후처리 장치, 소각로, 발전소 등의 미세 분진 포집 필터로서의 응용을 위해, 카본 파이버에 SiC 휘스커를 증착하는 실험을 진행하였다. 휘스커 증착 공정은 촉매없이 SiC 휘스커를 카본 파이버 위에 화학증착하였다. 휘스커 성장 시 증착 조건의 변화를 통하여 다양한 휘스커의 증착 형태 및 미세구조를 관찰하였다. 또한 높은 포집 효율 및 기체투과도를 갖추기 위해, 휘스커가 증착된 시편의 포집효율 및 기체투과도 향상을 위한 실험을 진행하였다. 해당 실험의 결과로, 증착된 필터는 70% 이상의 포집효율을 보이면서도 기체 투과도는 현재 상용화되어 있는 코디얼라이트보다 5배 이상 높았다. 또한 필터에 추가적인 SiC 침윤공정을 통하여 시편의 내산화성, 내마모성, 내열성 등의 특성이 향상됨을 확인하였다.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.2
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• pp.217-224
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• 2012

In general, transportation sources include both on-road vehicles and off-road equipment. Off-road vehicles have usually used diesel engines, which have the disadvantage of high NOx emission. Common rail direct injection (CRDI) and after-treatment systems have been applied to meet the exhaust gas emission regulations for diesel vehicles. In the present, agricultural machinery has satisfied the Tier 3 emission regulations by using waste gate turbocharger (WGT) and internal exhaust gas recirculation (EGR). In this paper, the combustion and emission characteristics of an EGR system applied to a 56kW off-road vehicle in non-road transient cycle (NRTC) mode have been investigated. The EGR map was made from foundation experiments determining the EGR duty for all engine operating conditions, and then this map was applied to the NRTC mode. Consequently, the NOx emission was reduced by the EGR system, and the Tier 4 interim emission regulations were satisfied by using both the EGR system and an after-treatment system.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.16 no.3
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• pp.76-81
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• 2017

In this research, to cope with the exhaust being reviewed to establish legal regulations for domestic small vessels, a basic experiment on an exhaust emissions post-treatment system was conducted to construct the design data required for securing a localized technology. The data was secured based on the arithmetic mean calculated through setting the engine load to 25%, 50%, and 75% and conducting five. A 2800-cc turbo charger diesel-type engine was used in the experiment, and an engine dynamometer was used in the conducted tests. As a result, NOx was reduced by approximately 20% and PM was reduced by approximately 97%. Although the results indicated no significant changes to CO in test mode-1, it was greatly reduced as it transitioned into the next phase.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.9 no.3
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• pp.136-142
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• 2000

With the significant growth of the number of vehicles environmental problems is raised. NOx SOx, and PM emissions in diesel powered vehicles are larger than that in gasoline because the development of pollutants reduction techniques has not been yet achieved. So it is need to develop after-tratment or to convert into alternative fuel to satisfy emission regula-tion. Among the after-treatment systems to reduce the diesel emissions studies with diesel oxidation catalyst(DOC) are done greatly. In this study using DOC reduction efficiency with the change of temperature and catalyst loading was calculated through measurements of CO, HC, PM. and SOX.

• Transactions of the Korean Society of Automotive Engineers
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• v.20 no.5
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• pp.145-151
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• 2012

New design of catalytic converter is proposed by optimization of DFSS (Design For Six Sigma) and DOE (Design Of Experiment) method which is based on taguchi matrix. As a result of the optimization of design of catalytic converter, this paper classifies Exhaust-downpipe shapes with 3 parameters to increase flow velocity uniformity of front catalytic substrate face from CFD results. after finishing with L9 Taguchi test matrix, it can be found the main effect of each design parameter of concept model, and optimal design level. in conclusion, it can be increase flow uniformity from 0.60 upto 0.80 with optimal diffuser shape for Turbo-charger.

• Clean Technology
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• v.7 no.1
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• pp.65-74
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• 2001

Modified dip-coating method 8.3 times shorten in solution volume-coated and 83.3 times in coating time than existing dip-coating method. Coating weight increased nearly 2~3 times. So modified dip-coating method is evaluated that it is economic and has a efficiency. When we make an experiment in coated $LaCoO_3$ on ceramic monolith in modified dip-coating method which use 2 coating applications with relative viscosity $0.006202kg{\cdot}m/sec$, it showed a superior reaction at 88.56mg per ceramic unit gram in NO-CO reaction(optimum coating amount). When we make an experiment in the same size of ceramic filter cell with different conditions 100, 200cell per square inch, the result in low temperature($200^{\circ}C{\sim}350^{\circ}C$), 200cell3 per square inch is 6~23% higher in NO reduction and 11% in CO oxidation than 100cell per square inch. It is because the more the number of cells in the ceramic filter increase, the more catalytic surface area is expanded.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.4
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• pp.371-376
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• 2012

The experimental test was conducted for a heavy-duty DME bus in JE-05 exhaust gas test mode using a chassis dynamometer, exhaust gas analyzers, and a PM measurement system. The heavy-duty DME bus was not equipped with after-treatment systems such as DOC or DPF. The dynamic behavior, emission characteristics, and fuel economy of the bus were investigated with an 8.0-liter, 6-cylinder conventional diesel engine. The results showed that the dynamic behavior in DME mode was almost the same as in diesel mode. However, there was little difference among the two operation modes for $NO_x$ and CO emissions. THC emissions were lower for DME mode than for diesel mode. Also, the amount of PM emissions was remarkably lower than for the diesel mode because DME contains a greater amount of oxygen than diesel. The data showed that $CO_2$ emissions were almost similar in the two modes but fuel economy (calculated using heating value) was lower for DME mode than for diesel mode.