• 한국자동차공학회논문집
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• 제10권6호
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• pp.108-116
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• 2002

The diesel engine is one of the most effective transport options available in all sizes and covering a wide range of applications. But, many researchers developing the diesel engine are facing tough challenges in view of the increasingly lower emissions standards. Thus, this study will explore the possible fuel additive technology to further reduce the emissions from the IDI diesel engine. The purpose of this study is to investigate the effects of oxygenated fuels on the exhaust emissions and to attain a better trade-off relation between smoke and NOx in four cylinder diesel engine. Experiments were conducted with oxygenated fuels as an effective way to improve the combustion efficiency. Some of oxygenated fuel(Diglyme and DEE) were added to the conventional diesel fuel which had no an oxygen content. Also, EGR was adopted for reducing NOx without any strong adverse effects on other exhaust emissions. This study concluded that exhaust emissions in diesel engine could be reduced by adding the oxygenated fuels which had lower boiling point, and the combustion efficiency was also improved as the oxygen content in fuel increased.

• 수산해양기술연구
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• 제57권3호
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• pp.256-263
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• 2021

In this study, blending oils of diesel oil and butanol were used as fuel oil for diesel engine to measure combustion pressure, fuel consumption, air ratio and exhaust gas emission due to various operating conditions such as engine revolution and torque. Using these data, the results of analyzing the engine performance, combustion characteristics and exhaust emission characteristics such as NOx (nitrogen oxides), CO₂ (carbon dioxide), CO (carbon monoxide) and soot were as follows. The fuel conversion efficiency at each load was highest when driven in the engine revolution determined by a fixed pitch propeller law. Except 30% butanol blending oil, fuel conversion efficiency of the other fuel oils increased as the load increased. Compared to diesel oil, using 10% and 20% butanol blending oil as fuel oil was advantageous in terms of thermal efficiency, but it did not have a significant impact on the reduction of exhaust gas emissions. On the other hand, future research is needed on the results of the 20% butanol blending oil showing lower or similar levels of smoke concentration and carbon monoxide emission rate other than those types of diesel oil.

• 한국수소및신에너지학회논문집
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• 제22권3호
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• pp.299-304
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• 2011

A hydrogen fueled 2 stroke free-piston engine with reverse uni-flow scavenging have a advantageous structure for the backfire occurrence, but it can reduce thermal efficiency by the circuit-flow to go through a exhaust-port. In this research, varied boost pressure, SVOT and exhaust pressure are used in a 2stroke free-piston engine with hydrogen fueled for studying the possibility of increasing thermal efficiency of free-piston hydrogen engine. As a result, to increase thermal efficiency of free-piston are suitable to supply the mixture after port closed the exhaust rater than to use the scanvenging. And it was increased by the exhaust pressure, to achieve it must be used the lean-mixture at SVOT aBDC $34^{\circ}$.

• 한국자동차공학회논문집
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• 제19권2호
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• pp.142-147
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• 2011

Compressed natural gas (CNG) is well known as one of the cleanest burning alternative fuels. Bi-fuel CNG vehicle can also run on gasoline or another fuel while dedicated natural gas vehicle is designed to run on natural gas only. Recently, increased attention has been focused on bi-fuel CNG/LPG taxi because of good fuel economy of CNG. A number of LPG taxis modified to CNG Bi-fuel vehicles are running in many cities. In this paper, the emissions characteristics of in-use passenger cars running on CNG and LPG were investigated. Chassis dynamometer test was used to measure exhaust emissions from an in-use fleet of 5 cars. Exhaust emissions were collected for CVS-75 driving mode. The test results showed that for CNG fuel mode, CO, $CO_2$ and NMHC emissions decreased to 9%, 12% and 14% respectively, and $CH_4$ and $NO_x$ emissions increased to 317% and 47% respectively.

• 한국컴퓨터정보학회논문지
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• 제25권2호
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• pp.189-195
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• 2020

본 연구에서는 배기가스가 흡수탑으로 균일하게 유입될 수 있도록 가스 부유식 흡수탑의 입구덕트와 안내깃을 다시 설계하여 탈황효율을 높이고자 한다. 산업용 보일러에서 대기오염 물질의 주 발생원인 중에서 황산화물의 오염물질을 저감하기 위해 기존의 장치를 다시 설계하여 해결하고자 한다. 이를 위하여 가스 부유식 흡수탑 내부에서 배기가스 중에 SOx 성분의 제거효율을 높일 수 있도록 배기가스, 슬러리와 재순환 흡착제가 균일하게 접촉하도록 변경한다. 그리고 보일러 출구에서부터 가스 부유식 흡수탑 출구까지 압력손실에 대한 초기 설계값과 CFD 값을 비교하여 검증한다. 또한 배기가스의 속도분포, 재순환 흡착제 농도분포, 액상 슬러리 거동, 압력손실을 각각 비교하였다. 그 결과는 보일러 출구에서부터 흡수탑 출구까지 압력손실이 감소하고, 배기가스의 편향이 최소화되므로 인해 탈황 효율이 개선되었음을 확인하였다.

• Journal of Biosystems Engineering
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• 제8권2호
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• pp.49-61
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• 1983

U shape multitube heat exchanger was equipped in the flue to recover the exhaust heat from the boiler system. The fluids of the exhaust heat recovery equipment were the flue gas as the hot fluid, and the water as the cold fluid. The flow geometry of the fluids was cross flow - two pass, the hot fluid being mixed and the cold fluid unmixed. The results of the theoretical and the experimental analysis and the economic evaluation are summarized as follows. 1) The heat exchanger effectiveness and the temperature efficiency of the hot fluid were about 35% when the fuel consumption rate was 140 - 150 L/15min. The temperature efficiency for the cold fluid ranged from 3.0% to 4.5%. The insulation efficiency ranged from 85% to 98%, which was better than the KS air preheater insulation efficiency of 90%. 2) The relationship between the fuel consumption rate, F, and the outlet temperature, $T_{h2}$, of the flue gas from the heat exchanger was $T_{h2}$ = 0.927F + 110. In order to prevent the low temperature corrosion from the coagulation of $SO_3$, it is necessary to maintain the fuel consumption rate above 82 L/15min. 3) The ratio of the exhaust heat from the boiler system to the total energy consumption was about 14.5%. With the installation of the exhaust heat recovery equipment, the energy recovery ratio to the exhaust heat was about 25%. Accordingly, about 3.6% of the total fuel consumption was estimated to be saved. 4) Economic analysis indicated that the installation of the exhaust heat recovery equipment was feasible to save the energy, because the capital reocvery period was only 10 months when the fuel consumption rate was 80 L/15min. 4 months when it was 160 L/15min. 5) Based on the theoretical and the experimental analysis, it was estimated to save the energy of about 18 million Won per year, if four heat exchangers are installed in a factory. 6) A further study is recommended to identify the relationship among the flow rate of the exhaust gas, the size of the heat exchanger and the capacity of the air preheater. For a maximum heat recovery from the exhaust gas an automatic control system is required to control the flow rate of the cold fluid depending on the boiler load.

• 유기물자원화
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• 제22권3호
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• pp.60-67
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• 2014

고층 공공주택의 화장실과 주방에 적용되는 배기 시스템은 기본적으로 두 종류의 환기팬이 적용된다. 가지 기본 유형의 지붕 팬이다. 그 하나가 자연 통풍력을 활용하는 무동력 팬이고 다른 하나는 자연 통풍력이 없을 때, 모터를 활용하여 강제로 구동하는 팬을 적용하는 방식이다. 자연/강제 겸용으로 지붕에 적용되는 환기팬은 회전축에 모터가 있습니다. 대한민국에는 많은 고층건물이 있다. 그러나 고층건물의 환기가 굴뚝효과에 의존된다고 판단하였기 때문에 이러한 건물의 실내에서 발생하는 오염물질의 제거에 대한 관심을 크게 갖지 않고 있다. 본 연구는 외기압력과 초고층아파트에 사용되는 배기연돌에 적용되는 차압에 의해 결정되는 연돌압력을 조사하기 위함이다. 본 논문은 화장실 배기풍량과 대기의 자연풍속을 변수로 하여 루프팬에 설치된 모타의 전력공급시간을 판단함으로써 기존 배기팬보다 향상된 배기효율을 예측하기 위해, 수행되었다.

• 한국주거학회논문집
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• 제15권3호
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• pp.101-108
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• 2004

To find more efficient exhaust effect, air curtain of upward or downward trend in gas table and left or right side of range hood were made. As result that film vapor from range hood lower part by digital camera, the air current change by moving existence and nonexistence of exhaust fan and direction of air curtain were known. Under all experiment condition, upward air curtain superior exhaust performance.

• 한국자동차공학회논문집
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• 제4권4호
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• pp.164-170
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• 1996

Among after treatment devices which reduce exhaust gas of diesel engine, diesel oxidation catalyst(DOC) with high reduction efficiency for gaseous matter and particulate matter is now being studied actively. In this study, an experiment was conducted to analyze the effects on factors of oxidaton characteristics and conversion efficiency of DOC. We tested to estimate change of engine performance whether a 11,000cc diesel engine equipps with DOC or not. We conducted test to estimate the reduction efficiency of exhaust gas in P-5 mode, in D-13 mode of heavy duty diesel regulation mode and in somoke opacity mode for two samples and also we conducted test to analyze the effects about both exhaust gas velocities 1,100rpm and 2,200rpm

• 한국자동차공학회논문집
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• 제2권6호
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• pp.18-28
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• 1994

An exhaust-heated gas turbine cycle equipped with a waste heat recovery boiler and ammonia absorption-type refrigerator using waste heat is newly devised and analyzed. The general performance of this cycle is compared with that of the conventional gas turbine cycle. This cycle shows a potential high efficiency. When 1500K of gas turbine inlet temperature the efficiency is 53 percent as compared to 45 percent for a conventional combined cycle. Suction cooling of this cycle leads to improve the thermal efficiency and the specific output.