• 전기학회논문지
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• 제57권12호
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• pp.2208-2212
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• 2008

This paper deals with the cost reduction design of a single-phase line-start permanent magnet(LSPM) motor. Due to high cost of the permanent magnet(PM), cost reduction can be effectively achieved by reducing PM volume. Therefore, motor characteristics according to the PM volume are calculated by using d-q axis equivalent circuit analysis, and the characteristic map is made. In the characteristic map, maximum torque and efficiency are shown according to motor parameters such as back electromotive force(back emf) and inductances; back emf represents the PM volume. Minimum back emf and inductances satisfying output performance are determined in the characteristic map. Then, motor geometry based on the prototype motor is optimized to get the determined parameters using response surface methodology(RSM) and finite element method(FEM). Through the presented cost reduction design, total PM volume is reduced to 32% of prototype model.

• 한국분무공학회지
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• 제29권2호
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• pp.68-74
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• 2024

As awareness of environmental pollution problems increases worldwide, interest in air pollutants is increasing. In particular, NOx and PM, which are major pollutants in diesel vehicles, are contributing significantly to emissions. As a result, its importance is increasing. In this study, based on research results applied to large diesel vehicles, the problem of natural regeneration caused by low exhaust gas temperature during low speed and low load operation is solved by applying a complex regeneration DPF that is not affected by temperature conditions to small diesel vehicles. The feasibility of application to small diesel vehicles was reviewed by measuring the emission reduction efficiency. As a result of the engine test, the power reduction rate and fuel consumption rate before and after device installation under full load conditions were 2.9% decrease and 3.5% increase, respectively, satisfying the standard for a 5% reduction, and as a result of the regeneration equilibrium temperature (BPT) test, the regeneration temperature was 310℃. appeared at the level. The reduction efficiency test results for the actual vehicle durability test equipment showed 97.3% PM, 51.0% CO, and 31.1% HC, while the city commuter vehicle had PM 97.5%, CO 61.7%, HC 40.0%, and the school bus vehicle had PM 96.8%, CO 44.4%, HC 34.3%, and low-speed logistics vehicles showed a reduction efficiency of 98.2% for PM, 36.0% for CO, and 45.7% for HC. Based on the results of this study, in the future, it is necessary to secure DPF technology suitable for all vehicle types through actual vehicle application research on temperature condition-insensitive composite regenerative DPF for medium-sized vehicles.

• 한국자동차공학회논문집
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• 제14권2호
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• pp.145-150
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• 2006

Recently emission regulation on diesel vehicles is getting stringent and research on aftertreatment technology such as DPF and DOC has been carried out actively. Even though PM(Particulate matters) reduction efficiency in DOC is relatively low but the structure is simpler and very effective in the reduction of gas materials and unregulated materials. Therefore it has been applied to smaller diesel vehicles. The aims of this research is to investigate the emission reduction characteristics of DOC; DOC performance of regulated and unregulated material emission reduction. It results a Pt based catalyst demonstrated higher emission reduction efficiency than a Pt-V based catalyst in CVS-75 mode, and also the reduction efficiency of unidentified material was excellent.

• 한국자동차공학회논문집
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• 제21권5호
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• pp.176-180
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• 2013

After-treatment apparatus ceramic DPF (diesel particulate filter) have been applied to reduce harmful particulate matters(PM) among emissions from diesel engines so far, but they are easy to be fragile and weak in thermal shock. This research aims to investigate a metal type filter which is superior in mechanical strength and heat conduction rate and is beneficial economically in manufacturing. Basic performance of metal DPF such asloading test, temperature gradient test, thermal shock test, heat resistant test and back pressure was carried out. And then their experimental data provided key informations in designing and manufacturing such as detailed structures of metal mesh filter. Also diesel engine and vehicle of 2957cc displacement was tested under lug-down 3 mode and CVS-75 mode. PM reduction efficiency was 54.5% using metal DPF without loss of performance and fuel consumption.

• 한국분무공학회지
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• 제29권2호
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• pp.53-59
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• 2024

Cars are one of the main causes of air pollution in large cities, and 34.6% of domestic air pollution emissions come from mobile sources, of which cars account for 69.6%. In particular, the importance of nitrogen oxides (NOx) and particulate matter (PM), which are major pollutants in diesel vehicles, is increasing due to their high contribution to emissions. Therefore, in this study, the problem of natural regeneration caused by low exhaust gas temperature during low speed and low load operation was solved by applying a complex regeneration DPF that is not affected by temperature conditions to large diesel vehicles with higher driving time and engine displacement than small and medium-sized vehicles. And the feasibility of application to large diesel vehicles was reviewed by measuring the emission reduction efficiency. As a result of the reduction efficiency test on the actual vehicle durability product, PM showed a reduction efficiency of 84% to 86%, and the reduction efficiency of gaseous substances showed a high reduction efficiency of over 90%. The actual vehicle applicability test was completed with three driving patterns: village bus vehicle, police car, and road-going construction equipment vehicle, and no device problems occurred until the end of the test. Both load and no-load smoke measurement results showed a smoke reduction efficiency of over 96%.

• 한국환경보건학회지
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• 제49권6호
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• pp.295-304
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• 2023

Background: Adolescents are relatively more sensitive than adults to exposure to indoor pollutants. The indoor air quality in classrooms where students spend time together must therefore be managed at a safe level because it can affect the health of students. Objectives: In this study, three types of green-wall models were applied to classrooms where students spend a long time in a limited space, and the resulting effects on reducing PM were evaluated. Methods: In the middle school classrooms which were selected as the experimental subjects, IoT-based indoor air quality monitoring equipment was installed for real-time monitoring. Three types of plant models (passive, active, and active+light) were installed in each classroom to evaluate the effects on improving indoor air quality. Results: The concentration of PM in the classroom is influenced by outdoor air quality, but repeated increases and decreases in concentration were observed due to the influence of students' activities. There was a PM reduction effect by applying the green-wall model. There was a difference in PM reduction efficiency depending on the type of green-wall model, and the reduction efficiency of the active model was higher than the passive model. Conclusions: The active green-wall model can be used as an efficient method of improving indoor air quality. Additionally, more research is needed to increase the efficiency of improving indoor air quality by setting conditions that can stimulate the growth of each type of plant.

• 한국대기환경학회지
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• 제18권5호
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• pp.411-417
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• 2002

The purpose of this study is to evaluate the emission reduction characteristics depending on the formation of the catalyst which influences the development of the diesel oxidation catalyst (DOC) suitable for small-sized diesel engines. We also attempted to suggest the feasibility of it as an after-treatment device. The reduction efficiency of DOC for CO and HC was proportional to the contents of precious metals, and the particulate matter (PM) has been reduced as much as 53∼59%. The reduction rate of soluble organic fraction (SOF) by DOC attachment revealed 100%. The composition of sulfate in PM increased from 3%, 7∼11% by installation of DOC. It is described that increase of sulfate contributed to the production of PM. This result also showed that the SOF and sulfate have trade-off relationship.

• 한국분무공학회지
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• 제26권4호
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• pp.163-170
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• 2021

Emergency generators normally use diesel engines. The generators need to conduct weekly no-load operation inspections to ensure stable performance at emergency situations. In particular, the generators with large diesel engines mainly use rectangle type filter substrates. In order to minimize hazardous emissions generated by generators, optimizing the reduction efficiency through CFD analysis of flow characteristics of PM/NO_X reduction system is important. In this study, we analyzed internal flow by CFD, which is difficult to confirm by experimental method. The main factors in our numerical study are the changes of flow uniformity and back pressure. Therefore, changes in flow characteristics were studied according to urea injector locations, selective catalyst reduction (SCR) diffuser angle, and filter porosity.

• 동력기계공학회지
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• 제12권5호
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• pp.34-39
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• 2008

The combustion purpose of diesel engine is to reduce the emission of green gas and to produce high output. Generally, the regulation matter of emission gas is largely diveded by 'THC', 'NOx', 'CO' and 'PM'. Among those matters, the most problem is to disgorge into 'PM', the character of diesel combustion. Diesel PM can be controlled using Diesel Particulate Filter, which can effectively reduce the level of soot emissions to ambient background levels. $NO_2$ generated by the DOC is used to combust the carbon collected in the DPF at low temperature. To certificate DPF device that is suitable to domestic circumstances, it is necessary to exactly evaluate the DPF devices according to the regulation of DPF certificate test procedure fur retrofit. To do carry out the above-mentioned description the understanding of that regulation like the standard of PM reduction is needed. In this study the test procedure including test cycle and BPT test condition was examined, and also the test result for specific DPF was analyzed. In every test like field test, PM reduction efficiency test and Seoul-10 mode test, no defect was showed.

• 대한교통학회지
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• 제32권2호
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• pp.93-105
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• 2014

본 연구는 자료포락분석(Data Envelopment Analysis: DEA) 기법을 활용하여 도로이동오염원 저감대책의 상대적 효율성 평가와 그에 기반하여 우선순위를 결정하였다. 현재 시행 중이거나 장래 계획 가능한 도로이동오염원 저감 대책들을 근거로 실효성 높은 자동차 온실가스와 대기오염물질 저감 대책 10개를 선정하여 시나리오를 구성하였으며, 대기오염물질 4개(CO, HC, NOX, PM), 온실가스 3개($CO_2$, $CH_4$, $N_2O$)물질에 대해 장래 통행패턴을 고려한 교통수요예측모형과 가변적 복합배출계수를 활용하여 2027년도를 최종 목표년도로 저감량을 산정하였다. 저감 대책들 간의 상대적 효율성을 평가하기 위해 DEA모형 중 초효율성 분석을 수행한 결과, 승용차 요일제 참여 확대 대책이 효율성 점수 1.879로 가장 우선순위가 높은 저감대책으로 선정되었으며, 버스전용차로 확대, CNG버스 보급 대책의 효율성이 높은 것으로 분석되었다. 본 연구의 결과는 자동차 온실가스와 대기오염물질 저감대책 우선순위 선정 결정 시 절대적인 자료로 활용될 수는 없지만 저감대책의 방향성을 제시하고 있으므로 향후 자동차 배출량 저감 정책방향 설정 및 체계적인 중장기 저감대책 수립에 기여할 수 있을 것으로 기대된다.