• Tribology and Lubricants
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• 제22권3호
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• pp.131-136
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• 2006

Cylinder bore wear may not be a problem in most current automotive engines. However, a small change in cylinder bore diameter can significantly affect the lubrication characteristics and ring axial motion. This in turn can cause to change inter-ring pressure, blow-by and oil consumption in an engine. Therefore, by predicting the wear of piston ring face, ring groove and cylinder bore altogether, the changed ring end gap and the changed volume of gas reservoir can be calculated. Then the excessive oil consumption can be predicted. Being based on the calculation of gas flow amount by the theory of piston ring dynamics and gas flow, and the calculation of oil film thickness and friction force by the analysis of piston ring lubrication, the calculation theory of oil amount through top ring gap into combustion chamber will be set. This is estimated as engine oil consumption. Furthermore, the wear theories of ring, groove and cylinder bore are included. Then the each amount of wear is to be obtained. The changed oil consumption caused by the new end gap and the new volume of oil reservoir around second land, can be calculated at some engine running interval. Meanwhile, the wear amount and oil consumption occurred during engine durability cycle are compared with the calculated values. Next, the calculated amount of oil consumption and wear are compared with the guideline of each pare0s wear and oil consumption. So, the timing of part repair and engine life cycle can be predicted in advance without performing engine durability test. The wear data of cylinder bore diameter are obtained from three engines before and after engine durability test. The calculated wear data of cylinder bore diameter are turn out to be twice of the lower bound of averaged test values at TDC and the lower bound at BDC.

• Tribology and Lubricants
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• 제22권4호
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• pp.211-217
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• 2006

Ring and groove wear may not be a problem in most current automotive engines. However, a small change in ring face and groove geometry can significantly affect the lubrication characteristics and ring axial motion. This in turn can cause to change inter-ring pressure, blow-by and oil consumption in an engine. Therefore, by predicting the wear of piston ring face, ring groove and cylinder bore altogether, the changed ring end gap and the changed volume of gas reservoir can be calculated. Then the excessive oil consumption can be predicted. Being based on the calculation of gas flow amount by the theory of piston ring dynamics and gas flow, and the calculation of oil film thickness and friction force by the analysis of piston ring lubrication, the calculation theory of oil amount through top ring gap into combustion chamber will be set. This is estimated as engine oil consumption. Furthermore, the wear theories of ring, groove and cylinder bore are included. Then the each amount of wear is to be obtained. The changed oil consumption caused by the new end gap and the new volume of oil reservoir around second land, can be calculated at some engine running interval. Meanwhile, the wear amount and oil consumption occurred during engine durability cycle are compared with the calculated values. Next, the calculated amount of oil consumption and wear are compared with the guideline of each part's wear and oil consumption. So, the timing of part repair and engine life cycle can be predicted in advance without performing engine durability test. The wear data of rings and grooves are obtained from three engines before and after engine durability test. The calculated wear data of each part are turn out to be at the lower bound of aver-aged test values or a little below.

• 설비공학논문집
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• 제24권7호
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• pp.545-552
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• 2012

The objective of this study is to analyze the effect on the energy consumption of an instant cooling type water purifier by the design parameters of the cooling tank. Initially, the simulation program was developed and verified. The simulation results showed that the energy consumption was reduced by replacing the shape of the cooling tank from a rectangular to a cube, increasing the evaporator length, decreasing the volume of the cooling tank, and increasing the performance of the insulator. The order of the effect magnitude on the energy consumption was as follows; volume of the cooling tank, conductivity and thickness of the insulator, shape of the cooling tank, length of the evaporator, and length of the water tube.

• 교육녹색환경연구
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• 제11권2호
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• pp.19-27
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• 2012

This study was carried out in order to establish the estimation equation for school power consumption using regression analysis based on collected power consumption for two years of weather data and schools are located in Central Changwon and Masan district in Changwon city. (1) The power consumption estimation equation for Heating and cooling is calculated using power consumption per unit volume, the difference between actual power consumption and results of estimation equations is 4.1%. (2) The power consumption estimation equation for heating load is showed 2.6% difference compared to actual power consumption in Central Changwon and is expressed 2.9% difference compared to that in Masan district. Therefore, the power consumption prediction for each school using the power consumption estimation equation is possible. (3) The power consumption estimation equation for cooling load is showed 8.0% difference compared to actual power consumption in Central Changwon and is expressed 2.9% compared to that in Masan district. As the power consumption estimation equation for cooling load is expressed difference compared to heating load, it needs to investigate influence for cooling load.

• 한국환경과학회지
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• 제12권12호
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• pp.1235-1243
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• 2003

Under controlled conditions in an environmental chamber, 24 experiments were performed to compare the ability of a Variable-Air-Volume/Bypass Filtration System(VAV/BPFS) to remove indoor pollutants and to conserve energy with the ability of conventional Variable Air Volume(VAV) system. The specific conclusions of this paper were; first, the VAV/BPFS was more efficient than the VAV system in removing particulate matter, TVOC, and target VOCs. The total effective removal rate of PM for the VAV/BPFS was two times as high as that of the VAV system. The total effective removal rate of TVOC for the VAV/BPFS was 20 percent higher than that of the VAV system. Also each target VOC concentration was reduced by using the VAV/BPFS. Second, clean air delivery rate was increased by using VAV/BPFS due to additional filtration rate. Otherwise, the VAV/BPFS decreased outdoor supply air rate above 25 percent relative to the rate of VAV system. Third, total energy consumption by the VAV/BPFS was lower than that of the VAV system during the period with indoor thermal load, occupied time. The energy saving of the VAV/BPFS ranged from 11 to 16 percent. The VAV/BPFS improves indoor air quality more efficiently than the VAV system, and it reduced energy consumption. Retrofitting the VAV system with the VAV/BPFS was easy The use of VAV/BPFS is, therefore, recommended far buildings with VAV system as well as for buildings at designing stage.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 춘계학술대회 논문집
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• pp.636-639
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• 2009

Fuel consumption measurement of Hydrogen fuel cell vehicle is considerably different form internal combustion engine vehicle such as carbon balance method. A practical method of fuel Consumption measurement has been developed for Hydrogen fuel cell vehicles. There are three method of hydrogen fuel consumption testing, gravimetric, PVT(Pressure, Volume and temperature), and Coriolis mass flow, all of which necessitate physical measurements of the fuel supply. The purpose of this research is to measure the fuel consumption of hydrogen fuel cell vehicles on chassis-dynamometer and to give information when the research is intended to develop method to measure hydrogen fuel consumption.

• 한국태양에너지학회 논문집
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• 제22권3호
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• pp.1-10
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• 2002

Relatively being economical in installation and easy in operation, hot-air heating system has been generally used in greenhouse for heating system regardless of high cost in maintenance and uneven distribution of air temperature. Therefore to overcome the disadvantages in maintenance and in distribution of air temperature and to improve efficiency of heating system, this experimental study is performed. This experimental study aims to improve the character of uneven temperature distribution in vertical direction and to reduce energy consumption for heating in a greenhouse. The experiment had been performed to investigate change of thermal environment and effects on reducing energy consumption for heating in greenhouse by additional surface insulation and reduction of indoor-air volume that come by installing transparent vinyl membranes with different height in each house. The results show that there is a wide difference in oil-energy consumption between houses according to condition of surface insulation and change of indoor-air volume. Furthermore, the results show that the efficiency of dual surface is higher than that of change of indoor-air volume in terms of energy saving.

• 대한지역사회영양학회지
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• 제19권3호
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• pp.250-257
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• 2014

Objectives: This study examined the impact of perceived volume on satiety using normal rice bowl, diet rice bowl and small rice bowl. Methods: Thirty-six normal weight college female students participated in this study once a week for 3 weeks. Three hundred grams of fried rice in a normal rice bowl (1st week), 300 g of fried rice in a diet rice bowl (2nd week), and 300 g of fried rice in small rice bowl (3rd week) were served to the same participants over three consecutive weeks. After each lunch, the consumption volume of fried rice and the satiety rate were measured. Results: The consumption volume of fried rice was 248 g (414.5 kcal) with a normal rice bowl, 254 g (429.8 kcal) with a diet bowl, and 270 g (456.8 kcal) with a small rice bowl. Results showed that the subjects who were eating from the small rice bowl ate more fried rice (p<0.05) than eating from the normal rice bowl and diet rice bowl. However, the satiety rate of fried rice in a diet rice bowl was significantly higher than that of normal rice bowl and small rice bowl (p<0.05). The five point scale of perceived volume on fried rice served normal rice bowl, diet rice bowl and small rice bowl were 2.4, 4.0 and 2.1. Conclusions: The visual cue plays a critical role in determining satiety and that perceived volume is perhaps more important than actual volume of consumed food in determining the level of fullness.

• 한국도로학회논문집
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• 제13권4호
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• pp.167-175
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• 2011

효율적인 도로의 설계와 관리를 위해서는 도로건설의 경제성 분석이 중요하며 이를 위해서는 도로 상태별 차량별 유류소모량의 평가가 필요하다. 도로에서는 초기 건설비용, 유지보수비용, 차량운행비용, 지정체비용 등이 발생되는데, 도로의 경제성 분석을 위해서는 초기 건설비용, 유지보수비용 등과 같은 관리자비용과 차량운행비용, 지정체비용 등과 같은 이용자비용을 모두 포함한 사회적 비용이 고려되어야 한다. 이 중 차량운행비용은 교통량에 따라 그 비용이 변화되므로 차량운행비용 항목의 큰 부분을 차지하는 유류소모량 또한 교통량에 따라 변화하게 된다. 그런데 유류소모량은 차량의 주행속도 및 도로포장의 상태, 특히 평탄성에 따라 크게 변화되므로 도로의 경제성 분석을 위한 차량운행비용의 산정을 위해서는 주행차량에 대해 도로 상태에 따른 유류소모량을 평가하여 경제성 분석에 반영해야 할 필요가 있으나 아직 이를 고려하지 못하고 있는 상황이다. 본 연구에서는 국내에서 운행되는 승용차에 대해서 도로 상태별 유류소모량 추정모델을 개발하였다. 우선 우리나라의 교통시설 투자평가 및 도로건설의 예비타당성 조사에서 차량운행비용 산정을 위해 사용되고 있는 주행속도와 유류소모량의 관계식을 고찰하고, 승용차를 대상으로 도로포장의 평탄성에 따른 유류소모량 변화의 관계를 실제 도로에서 실측하여 평탄성과 유류소모량 변화의 관계를 분석하였다. 실험 결과, 평탄성에 따른 유류소모량의 변화는 평탄성이 1m/km 증가하였을 경우 100km 주행시 약 $80m{\ell}$ 정도의 비율로 유류소모량이 증가하는 것으로 확인되었다. 따라서 도로의 설계 및 유지관리에 있어서 보다 정확한 경제성 분석을 수행하기 위해서는 도로포장의 평탄성에 따른 유류소모량 변화를 고려해야 할 필요가 있다.

• 한국환경보건학회지
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• 제34권1호
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• pp.95-100
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• 2008

An automatic titration system using a PC-camera with a color filter on its lens was used in the $KMnO_4$ consumption test of tap water and distilled water in relation to blank tests. The very faint pink color of titration end point could be effectively detected by using a yellow cellophane paper as a color filter. The average hue value (Havg) of 192 pixels in the image of the sample solution being titrated was computed and followed up at regular time intervals during titration in order to detect the titration end point. The Havg decrease of 2 degrees from the average of first 10 Havgs was regarded as reaching the end point. The volume of 0.01N $KMnO_4$ consumed by a tap water sample was $0.728{\pm}0.022ml$ in manual titration and $0.735{\pm}0.013ml$ in automatic titration (p=0.580). The volume of 0.01N $KMnO_4$ consumed by a distilled water sample was $0.383{\pm}0.015ml$ in manual titration and $0.367{\pm}0.015ml$ in automatic titration (p=0.252). The high p-values for t-test suggested that there were good agreements between manual and automatic titration data and the automatic method proposed in this article was considered to effectively replace the manual titration.