LP EGR 적용을 위한 승용 디젤 엔진 보정 기법에 관한 연구

정동영(Dongyoung Jeong),정재우(Jaewoo Chung),김남호(Namho Kim),강정호(Chungho Kang),김태진(Taejin Kim) 한국자동차공학회 2010 한국자동차공학회 학술대회 및 전시회 Vol.2010 No.11

Diesel engine technology is developing to satisfy strong exhaust gas regulations and lower fuel economy. In the event of study, the HP EGR system which is to reduce NOx generation of the engine emission is changed to LP EGR system which investigate in NOx and BSFC respects. In structural alterations to the LP EGR, the pressure drop should be minimized in EGR gas path. And Applying the LP EGR is of benefit to reduce the NOx generation above 40% in same BSFC level, in this case, the vane control of variable geometry turbocharger is controlled in maximum compressor efficiency area, and the LP EGR valve is operated the wipe open state, the back pressure valve is controlled to consider limit A/F and reduced BSFC. And the equation of the mass flow through the nozzle is modified for EGR valve and back pressure valve. In using modified equation predicts the pressure of before back pressure valve and accompanying pressure is used to predict EGR rate. And that the predicted EGR rate is verified to compare with engine test data.

LP loop EGR 디젤 엔진의 EGR cooler 적용 특성

정재우(Jaewoo Chung),정동영(Dongyoung Jeong),김남호(Namho Kim),강정호(Chungho Kang),서영호(Youngho Seo),김병수(Byoungsu Kim),김태진(Taejin Kim) 한국자동차공학회 2010 한국자동차공학회 학술대회 및 전시회 Vol.2010 No.11

In this study, an EGR system of EURO4 engine was modified to LP loop EGR system considering the minimize the pressure drop and LP EGR cooler application characteristics was investigated using various EGR cooler applications. As the investigation , LP EGR cooler fouling test was performed during 50 hr at LP loop EGR engine driving condition and as the fouling test result, EGR cooler fouling phenomena did not happened. Also, EGR gas cooling performance and pressure drop through EGR cooler was measured at engine test. From LP loop EGR engine tests, Engine fuel economy performance was improved about 4%∼7% compared with the base EURO 4 engine value at similar NOx emission level, And it is found that intake manifold temperature is effected by EGR cooler, EGR/ fresh air mixing and intercooler cooling capacity. On the other hand, EGR cooler has some effects on cooling the EGR gas upstream of EGR valve and compressor, EGR cooler restrict the gas temperature in LP EGR system and protect the LP EGR components. So high EGR rate could be realized by application of a LP EGR cooler. In Hybrid EGR system, monitoring of LP EGR fraction has been point out as a technical problem, so, in this study, a LP EGR mass flow rate measurement method using EGR cooler was made to attempt.

제품 및 리뷰 유형이 리뷰 의존도에 미치는 영향

배경한(Kyeonghan Bae),정동영(Dongyoung Jeong),김지영(Alex Jiyoung Kim) 한국소비문화학회 2023 소비문화연구 Vol.26 No.1

최근 COVID-19 확산과 함께 온라인 쇼핑 빈도가 증가하며, 소비자들은 온라인 쇼핑에 내재되어 있는 제품 불확실성을 줄이기 위해 제품 리뷰에 의존하는 경향이 높아지고 있다. 마케팅 맥락에서의 리뷰 연구들은 주로 제품 유형(물질재 vs. 경험재)에 따라 달라지는 소비자들의 리뷰 의존도에 초점을 두고 진행되어 왔지만 일관된 결과를 제시하지 못하고 있는 실정이다. 더욱이, 시각적인 정보를 제공하여 객관성을 전달하는 사진 및 동영상이 추가된 리뷰(vs. 텍스트)에 대한 제품 판매자 및 소비자들의 수요가 늘어나고 있음에도 이에 대한 고찰과 마케팅적 가치에 대한 연구는 부족하다. 따라서 본 연구에서는 제품 유형에 따라 달라지는 소비자 리뷰 의존도에 대한 일관되지 못한 연구 결과를 통합하고, 리뷰의 유형에 따른 조절 효과를 알아보고자 한다. 국내 검색 엔진의 쇼핑 데이터에 바탕을 둔 연구 결과는 다음과 같다. 먼저 소비자는 물질재 제품을 구매할 때 보다 경험재 제품을 구매할 때 리뷰에 덜 의존하는 경향이 있는 것으로 나타났으며, 텍스트 리뷰가 사진 및 동영상이 추가된 리뷰 보다 리뷰 의존도에 더 긍정적 영향을 미치는 것으로 파악되었다. 하지만 경험재 제품을 구매할 때 사진 및 동영상이 추가된 리뷰가 제시되면 부정적이던 리뷰 의존도가 상쇄되는 것으로 나타났다. 이는 사진 및 동영상이 추가된 리뷰가 온라인 쇼핑의 불확실성을 감소시킬 수 있다는 사실로 해석될 수 있다. 따라서 본 연구는 소비자는 물질재 제품을 구매 할 때 리뷰에 더 의존한다는 결과를 제시함으로써 일관되지 못한 선행 연구 결과를 통합하며, 사진 및 동영상이 포함된 리뷰가 쇼핑 불확실성을 줄이는데 효과적임을 제시할 수 있다. As consumers' online shopping has increased due to the recent spread of COVID-19, consumers are increasingly relying on product reviews to reduce the uncertainty inherent in online shopping. Accordingly, many previous research have emphasized the importance of reviews, but studies related to reviews in the marketing context have mainly focused on the impact of reviews that vary rely on product types (materials vs. experiential). Nevertheless, the results of previous research are mixed. In particular, there is a lack of research on the marketing value and consideration of reviews (vs. text) with added photos and videos that can be used as a tool to reduce the uncertainty of online shopping. Therefore, this research analyzes the effect of product types on review rely and integrates mixed research results. In addition, we would like to find out how reviews with added photos and videos affect the rely on reviews that vary relying on the product type. The research results based on shopping data of domestic search engines are as follows. First, it was found that consumers tend to rely more on reviews when purchasing material goods products. Reviews with added photos and videos were found to have a negative effect on review dependence rather than reviews consisting only of text, which was found to be offset when purchasing experienced products. This can be interpreted as the fact that photo and video reviews can reduce the uncertainty of online shopping. Therefore, this research integrates mixed previous research results by first suggesting that consumers rely more on reviews when purchasing material products to reduce shopping uncertainty, and second, it can suggest that reviews containing photos and videos are effective in reducing this uncertainty.

DME 고압연료펌프 개발에 관한 연구

김남호(Namho Kim),정재우(Jaewoo Chung),강정호(Jeongho Kang),정동영(Dongyoung Jeong) 한국자동차공학회 2010 한국자동차공학회 학술대회 및 전시회 Vol.2010 No.11

DME is expected for future clean energy, especially for application to diesel engine. But DME fuel for adapt to commercial diesel engine has a defect, because of its chemical properties. So, we had to develope a DME high pressure pump for common-rail injection system. The DME high pressure pump is horizontal two plunger type pump. because of its simple structure, and minimum components. And at the development of DME high pressure pump, it is considered the DME fuel properties like as low lubrication property, low bulk modulus property and low density and calorific value properties. DME pump design concept of this study is general and thus may be applied to the common-rail systems for other alternative fuel.

디젤엔진을 이용한 2단 VGT 및 EGR 적용특성에 관한 실험적 고찰

정재우(Jaewoo Chung),강정호(Jeongho Kang),이호길(Hogil Lee),김남호(Namho Kim),정동영(Dongyoung Jeong) 한국자동차공학회 2009 한국자동차공학회 학술대회 및 전시회 Vol.2009 No.11

In this paper, it is discussed that the NOx and smoke emission performances in a Diesel engine equipped with 2-stage VGT(variable geometry turbocharger) and EGR loop systems of 2 types As the installation of 2 stage VGT system, intake air flow rate could be increased. So, Nox could be reduced by high EGR rate compared with the base single VGT system. And , in EGR loop type engine tests, characteristics of LP(low pressure) and HP(high pressure) EGR system with 2-stage VGT system have been investigated. In these tests, performances of Lp loop EGR system have been seriously effected by the back pressure caused by BPV(back pressure valve) angle and EGR loop system.

Unconfined Compressive Strength of Soil-Cement Pavement with Recycled Red Mud

Lee Yunkyu(이윤규),Baek Seungcheol(백승철),R. D. Holtz,Jeong Dongyoung(정동영) 한국지반환경공학회 2008 한국지반환경공학회논문집 Vol.9 No.7

알루미늄 제조 시 발생하는 산업부산물인 Red mud가 첨가된 흙-시멘트 포장 재료를 개발하기 위하여 일축압축강도시험을 수행하였으며 Red mud 함유율, 시멘트 함유율, Fly ash 대체 비율 및 모래의 대체 비율이 일축압축강도에 미치는 영향을 검토하기 위하여 양생기간 7일, 14일 및 21일에 대한 공시체를 제작하였다. 시험결과, Red mud와 Fly ash 함유량이 감소할수록 시멘트 함유량이 증가할수록 일축압축강도는 증가하였고, 화강풍화잔류토를 사용할 경우 모래의 대체 비율에 따른 일축압축강도에 미치는 영향은 없는 것으로 나타났다. The unconfined compressive strength of soil-cement mixed with red mud, an industrial by-product of alumina production, was investigated in the laboratory. The investigation involved laboratory tests under the various conditions such as red mud content, cement content, fly ash content and ratio of soil replacement with sands. The unconfined compressive strength tests were performed at 7, 14 and 21 days after specimen preparation. Results of the study show that the unconfined compressive strength increased as red mud and fly ash content decreased and cement content increased. Increasing the soil replacement ratio with sands had an insignificant effect on compressive strength because the soil had a similar particle size as the replacement sands.

매연 및 입자상물질 측정결과의 상관성에 관한 연구

정재우(Jaewoo Chung),강정호(Jeongho Kang),김남호(Namho Kim),이호길(Hogil Lee),정동영(dongyoung Jeong),정수진(Soo-Jin Jeong),강우(Woo Kang) 한국자동차공학회 2009 한국자동차공학회 부문종합 학술대회 Vol.2009 No.4

Amount of PM from Diesel engine is restricted by regulations. So, many researched on the reduction method of PM from Diesel engine have been performed. But measurement of PM mass with MDT is very expensive and hard. So, in mant engine researches, Smoke meter or Opacimeter is used to measure smoke performances. In this study, relationships between tests results from 3type equipment(smoke meter, opacimeter, MDT) are introduced also effects of HC concentrations on the Total PM mass concentrations are investigated with total PM model.