• 한국자동차공학회논문집
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• 제11권2호
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• pp.111-118
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• 2003

Recently, environmental damage to urban area becomes serious problem due to the exhaust emissions by increasing the number of vehicle. Especially, exhaust emission from diesel vehicles are blown to be harmful to human health and environment. Photoacoustic Spectroscopy system is very useful technology for simultaneous and continuous measurement of the various components of the automotive exhaust gas. In this study, in order to reduce emission gases from automobile, we tried to develop the measurement system of Photoacoustic Spectroscopy. To improve performance of high sensitive Photoacoustic Spectroscopy system for automotive exhaust emissions, the shape of Photoacoustic Spectroscopy cell was optimized to use the flow analysis. And Exhaust emission data of the 1,500cc gasoline engine was fixed the working fluid. The characteristics of fluid flow for cell were analyzed by various conditions in detail.

• 한국자동차공학회논문집
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• 제17권4호
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• pp.93-100
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• 2009

Intake/exhaust valve timing and exhaust cam lift were changed to control the internal exhaust gas recirculation (IEGR) and combustion phase of homogeneous charge compression ignition (HCCI) engine. To measure the IEGR rate, in-cylinder gas was sampled during from intake valve close to before ignition start. The lower exhaust cam made shorter valve event than higher exhaust cam and made IEGR increase because of trapping the exhaust gas. IEGR rate was more affected by exhaust valve timing than intake valve timing and increased as exhaust valve timing advanced. In-cylinder pressure was increased near top dead center due to early close of exhaust valve. Ignition timing was more affected by intake valve timing than exhaust valve timing in case of exhaust valve lift 8.4 mm, while ignition timing was affected by both intake and exhaust valve timing in case of exhaust valve 2.5 mm. Burn duration with exhaust valve lift 2.5 mm was longer than other case due to higher IEGR rate. The fuel conversion efficiency with higher exhaust valve lift was higher than that with lower exhaust valve lift. The late exhaust and intake maximum open point (MOP) made the fuel conversion efficiency improve.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 추계학술대회논문집B
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• pp.150-155
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• 2000

Exhaust emissions from vehicles are the main source of air pollution. Many researchers are trying to find the way of reducing vehicle emissions, especially in the cold transient period of the FTP-75 test. In this study, UEGI (Unburned Exhaust Gas Ignition) technology, warming up the close-coupled catalytic converter (CCC) by igniting the unburned exhaust mixture using two glow plugs installed in the upstream of the catalyst, was developed. It was applied to an exhaust system with a hydrocarbon adsorber to ensure an effective reduction of HC emission during the cold start period. Results showed that the CCC reaches the light-off temperature (LOT) in a shorter time compared with the baseline exhaust system, and HC and CO emissions are reduced significantly during the cold start.

• 한국자동차공학회논문집
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• 제13권4호
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• pp.90-96
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• 2005

The improvement of combustion stability is very important because it is closely related to the exhaust emission concentrations as well as the fuel consumption during the cold start of SI engine. In our previous studies, the spark and exhaust valve timings were retarded individually from the baseline case to increase the exhaust gas temperature far fast warmup of a close-coupled catalyst. In the study, it was found that combustion stability during cold start becomes worse when the valve timing is retarded from the baseline conditions. The spark and valve timings were simultaneously changed from the baseline conditions to find out the variation of combustion stability during cold start of an Sl engine. Through the study. retarded spark timing by $5^{\circ}$ CA helps improvement of $COV_{imep}$ by $2\%$ and $15^{\circ}C$ increase of exhaust temperature. Retarded exhaust valve timing makes the exhaust gas temperature increase by $30^{\circ}C$, but it also deteriorates the $COV_{imep}$ by $1\%$.

• 한국가스학회지
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• 제21권1호
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• pp.80-86
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• 2017

본 논문에서는 유해배출물질 저감장치인 DPF의 문제를 해소하기 위하여 제안된 것으로서, 양방향으로 분기되는 배기가스 유로를 통하여 자동차의 엔진 구동시 발생되는 배기가스를 효율적으로 유도하고 2개의 DPF 장치를 장착함으로서 교번작용을 통한 유해배출물질 정화 및 재생연소특성을 효율적으로 적용할 수 있도록 개발한다. DPF 내부에 입자상물질 적층현상으로 인한 배기가스의 내부압력 증가를 피할 수 있고, 출력저하 및 연비효율이 떨어지는 등의 문제를 획기적으로 개선하여 고효율의 출력을 유도할 수 있는 자동차 배기가스 정화 시스템을 제공하려는데 그 목적이 있다.

• 한국자동차공학회논문집
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• 제11권2호
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• pp.63-68
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• 2003

The purpose of this study was to investigate reduction of exhaust gas temperature in LPG conversion engine from diesel. A conventional diesel engine was modified to a LPG(Liquified Petroleum Gas) engine that diesel fuel injection pump was replaced by the LPG fuel system. The research was peformed with measurement of exhaust gas temperature by varying spark ignition timing, air-fuel ratio, compression ratio, EGR ratio and different compositions of butane and propane. The major conclusion of this work were followed. (i) Exhaust gas temperature was decreased and power was increased with the advanced spark ignition timing. (ii) Exhaust gas temperature was decreased with lean and rich air-fuel ratio. (iii)Exhaust gas temperature was decreased and power was increased with the higher compression ratio. (iv) Engine power and exhaust temperature were not influenced by varied butane/propane fuel compositions. (v) Finally, one of the important parameters in reduction of exhaust gas temperature is spark ignition timing among the parameters in this study.

• 에너지공학
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• 제18권1호
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• pp.69-73
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• 2009

자동차로부터 배출되는 배출가스의 규제가 최근 더욱 강화되고 있다. 이러한 엄격해지는 규제는 배출가스를 줄이는 대체연료의 개발에 더욱 박차를 가하게 된다. 본 연구는 가솔린, 디젤, LPG 연료를 사용하는 동급의 자동차를 이용하여 배출가스의 특성을 분석 비교하였다. 테스트 모드로는 최근 국내와 북미 배출가스의 주행모드로 사용되는 CVS-75모드를 사용하였다. 배기 특성은 주행조건에 하에서 연구되어졌다. 사용연료인 가솔린, 디젤, LPG연료에 따라 THC, CO, NOx의 배출가스의 특성을 연구했다. 연구결과, LPG연료에 비해 가솔린자동차가 9.8%의 배출가스 감소, 디젤자동차는 12.2% 증가를 나타냈다. 또한 CVS모드에서 가솔린과 LPG는 phase 1의 냉간시동구간에서 THC와 CO는 80%이상을 나타낸다.

• 한국자동차공학회논문집
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• 제7권8호
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• pp.123-131
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• 1999

Natural gas is one of the most promising alternative fuels for automotive vehicles. However, natural gas varies in compositional between the originating fields and may be further modified due to processing and additional mixing. These variations are known to affect engine performance and emissions through changes in fuel metering and combustion characteristics. In the present study, the effect of gas compositions on vehicle performance such as fuel economy, driveability and exhaust emissions was examined. Analysis are made of using 3 types of NGVs which were made by automakers and 6 different fuels which are selected in consideration of the variation in fuel composition on the worldwide market. The results may be utilized to develop natural gas natural gas engine in automaekrs and/or to establish the fuel standard in the refueling stations.

• 한국자동차공학회논문집
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• 제7권7호
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• pp.104-112
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• 1999

An experimental study for reducing the exhaust hydrocarbon emission at spark ignition engine using timed secondary air injection is carried out . In this study, secondary air injection timings and durations are controlled to decrease the hydrocarbon emission and to increase exhaust gas temperature at cold and warm-up engine conditions. The hydrocarbon reduction rate and exhaust gas temperature are compared between timed secondary air injection and continuous air injection. The optimum secondary air injection timing for reducing the hydrocarbon emission is at the exhaust valve open timing. At some engine conditions , the hydrocarbon emissions are decreased to 10% of engine raw values and exhaust gas temperatures increase by 20$0^{\circ}C$ with times secondary air injection . Timed secondary air injection has more hydrocarbon reduction rate that continuous secondary air injection except some engine conditions.

• 한국자동차공학회논문집
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• 제6권6호
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• pp.218-225
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• 1998

FTIR spectroscopy, useful technology for simultaneous and continuous measurement of the various components of the automotive exhaust gas, is utilized to investigate catalytic reaction charactristics of methane and a few unregulated exhaust emissions of NGV. Major findings are (1) catalytic reaction characteristics of methane measured in unsteady states of varying temperature are similar to those measured in steady states, (2) about 24 % of NO was oxidized to $NO_2$ as soon as they encounter catalysts, (3) study of formaldehyde suffers from difficulties in measurement due to the proximity in wavenumber of formaldehyde and methane, and requires an analyzer of higher resolution and accuracy than used in this study.