• 주택과사람들
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• s.199
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• pp.34-35
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• 2006

선진국에서는 선시공 후분양이 일반적이다. 후분양은 소비자가 지어진 주택을 살펴보고 아파트를 살 수 있어 유리하지만 대규모 주택을 짓는 건설사는 사업 초기에 자금 압박이 크다. 시민 사회단체에서는 선시공 후분양이 주택 값을 내릴 수 있는 묘안처럼 이야기하지만 선분양, 후분양 모두 장단점이 있다.

• 주택과사람들
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• s.198
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• pp.36-37
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• 2006

선진국에서는 선시공 후분양이 일반적이다. 후분양은 지어진 주택을 소비자가 살펴보고 아파트를 살 수 있어 유리하지만 대규모 주택을 짓는 건설사는 사업 초기에 자금 압박이 클 수 있다. 시민 사회단체에서는 선시공 후분양이 주택값을 내릴 수 있는 묘안처럼 이야기하지만 선분양, 후분양 모두 장단점이 있다.

• Journal of ILASS-Korea
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• v.9 no.1
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• pp.15-20
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• 2004

The post injection effect to enhance aftertreatment devices' performance is essential to meet future stringent emission standards by controlling exhaust gas temperature and emission pollutants. The test has been made with commercial common rail diesel engine by post injection manipulation, to optimize exhaust gas temperature while guarantee low fuel penalty. The optimization was done at 1500, 2000 and 2500[rpm] for 2, 4[bar] condition which show low exhaust gas temperature. The main purpose of this test is dedicated to understand mechanism of exhaust gas temperature rise while optimizing

• Journal of ILASS-Korea
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• v.22 no.2
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• pp.87-95
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• 2017

Recently, as the interest in environmental issues have increased around the world, the regulation on vehicle exhaust have been tightened in each country. To satisfy such tightened exhaust regulation, automotive manufactures are forced to equipped Diesel Particulate Filter (DPF) at Diesel vehicles. If DPF is used for a long time, DPF regeneration should be performed. The objective of this study is to research on post injection for DPF regeneration. The result of the study was that it was desired that retarding post injection timing, lower load of engine and smaller the amount of main fuel injection, for DPF regeneration. Oil dilution was tended to increase as load was lower, amount of post injection was increased, and post injection timing was retarded.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.1
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• pp.193-201
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• 2014

A numerical study has been carried out to analyze the combustion characteristics in heavy duty diesel engine with post injection for reducing NO emission. For verification of numerical study results, calculated cylinder pressure was matched to experimental data. In this study, post injection timing and amount of post injection were modified as parameters, but the total amount of injection fuel was maintained. As the results, maximum cylinder pressure increases above minimum 2% by post injection and end of pressure curve is decreased rapidly. The more dwell time and amount of post injection fuel are, the more pressure drop occurs. And trade-off relation of NO and soot are appeared. In the results, NO was reduced without deterioration of cylinder pressure under condition of $10^{\circ}$ CA dwell time and main 60%, post 40% fuel portion.

• 한국연소학회:학술대회논문집
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• 2012.11a
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• pp.179-182
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• 2012

Effect of double post injections on diesel PCCI combustion with focus on HC emission was investigated in a single-cylinder direct-injection diesel engine. The ISFC, HC and CO emissions were reduced by single or double post injections. The application of double post injections could also improve the trade-off relationship between NOx and HC emissions under wide EGR rate range.

• Korean Journal of Construction Engineering and Management
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• v.5 no.6 s.22
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• pp.218-225
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• 2004

The supply for the apartment complex in Korea has been accomplished by the sale before building system as a way of institutional means to support massive housing supply in the past. Although this sale before building system has helped the provision of the housing, the necessity of that has been weakened in the current housing market. As this market is changed to emphasize on consumer, the necessity of conversion to sale after building system was raised and finally enforced partially. However, the sale after building system has difficulty in ensuring construction fund and the safety of housing business. So, the diversification in the style of business structure we and the strategy for the activation of construction fund will solve these problems. Consequently, this essay examine the change and influence in the construction fund after adopting sale after building system and suggest the appropriate strategy in project financing for providing fund and reducing the risk in construction business.

• Transactions of the Korean Society of Automotive Engineers
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• v.19 no.2
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• pp.78-83
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• 2011

Diesel engine has many advantages such as high thermal efficiency, low fuel consumption and low emission of CO2. However, the diesel engine faced with strengthened emission regulation about NOx and PM. To suppress NOx emission, after-treatment systems such as Lean NOx Trap (LNT), Selective Catalytic Reduction (SCR) are considered as a more practical strategy. This paper investigated the performance of Lean NOx trap of the 4 stroke diesel engine which had a LNT catalyst. Characteristic of exhaust emission at NEDC mode was analyzed. From this result, the effect of nozzle attaching degree, injection quantity and gas flow change on NOx conversion performance was clarified.

• Particle and aerosol research
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• v.8 no.2
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• pp.55-68
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• 2012

Particulate matters (PM) which are collected into a diesel particulate filter (DPF) system have to be periodically removed by thermal oxidation. In this report, we fabricated an electrohydrodynamic-assisted pressure-swirl nozzle to spray diesel droplets finer. Atomization performance of the nozzle was evaluated using both experimental and numerical methods. Two types of nozzle designs, the charge induction type and the charge injection type, were tested. While the former generated diesel droplets of $400\;{\mu}m$ at an applied electric potential over 10 kV, the latter presented the droplets smaller than $23\;{\mu}m$ at an applied electric potential of 8 kV. The numerical simulation results showed that the reduced size of droplets caused higher evaporation of droplets and therefore the increased temperature, which would eventually increase the regeneration performance of the DPF system.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.5
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• pp.40-57
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• 2004

The effects of triple (pilot, main and after) injection on combustion and emission characteristics in a HSDI (High-Speed Direct Injection) diesel engine were investigated using a single-cylinder optical diesel engine equipped with a common-rail injection system. The pilot injection affected the spray and combustion evolution of the following main injection. It was found that the pilot injection reduced the ignition delay, which led to lowered NOx (Nitric Oxides) level, and increased IMEP (Indicated Mean Effective Pressure) due to slow combustion pace during an expansion stroke. The after-injection was shown to be effective in reducing PM (Particulate Matter) even when a small amount of fuel was added. The results suggest that a proper combination of individual injection strategy could bring about a good synergetic effect on engine performance and emission.