• Journal of Energy Engineering
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• v.13 no.2
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• pp.161-165
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• 2004

Evaporative emissions from gasoline powered vehicles continue to be a major concern. The performance of carbon canister in evaporative emission control systems has become an important aspect of overall fuel system development and design. A vehicle's evaporative emission control system is continuously working, even when the vehicle is not running, due to generation of vapors from the fuel tank during ambient temperature variations. In this study, the effects of evaporative emissions on the engine performance were investigated. The experimental results show the effectiveness of this system for future exhaust emissions and enhanced evaporative emissions. This paper discusses the evaluation on the relationship between carbon canister condition and engine performance while engine is running.

• International Journal of Automotive Technology
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• v.7 no.1
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• pp.9-15
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• 2006

Prediction of the performance of a carbon canister in vehicle evaporative emission control system has become an important aspect of overall fuel system development and design. A vehicle's evaporative emission control system is continuously working, even when the vehicle is not running, due to generation of vapors from the fuel tank during ambient temperature variations. Evaporative emissions from gasoline powered vehicles continue to be a major concern. The objective of this paper is to clarity the flow characteristics and other such fundamental data for the canister during loading and purging are needed, and this data will prove valuable in the development of the canister. This paper is to evaluate the relationship between carbon canister condition and engine performance during engine operation, and the effects of evaporative emissions on the engine performance were investigated.

• Transactions of the Korean Society of Automotive Engineers
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• v.19 no.4
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• pp.121-129
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• 2011

Hydrocarbons which are the main sources of VOCs from motor vehicles are emitted not only from the engine exhaust gas but also from evaporation of the fuel in storage and supplying systems. Evaporative emissions from gasoline fuel systems could be classified by diurnal, hotsoak and running loss. Diurnal loss test procedures are different as countries. Korea introduced new evaporative regulation in 2009 with 24hour VT-shed test procedure and relaxed emission standards. The estimations on different test procedures in this study show that the new Korean regulation get a little more severe than before and the 2 day diurnal loss test of U.S. is the most severe. So the test procedures as well as the stronger standards should be considered in the next evaporative emission regulation to reduce VOCs from motor vehicles. The important parameters to affect evaporative emissions are air and fuel temperature and fuel vapor pressure. Diurnal loss increases exponentially as rising air temperature and vapor pressure. The effects of vapor pressure on running loss are different as the capacities of canisters. Tests with simulating real temperature and driving conditions show that hydrocarbons in evaporative emissions could be more than those in exhaust gas in summer season because of the higher air temperature.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.6
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• pp.74-79
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• 2004

The effects of change in injection pressure on spray structure have been investigated in high temperature and pressure field. To analyze the structure of evaporative diesel spray is important in speculation of mixture formation process. Also emissions of diesel engines can be controlled by the analyzed results. Therefore, this study examines the evaporating spray structure by using a constant volume vessel. The injection pressure is selected as the experimental parameter, is changed from 72 MPa to 112 MPa with a high pressure injection system(ECD-U2). The PIV(Particle Image Velocimetry) technique was used to capture flow variation of the evaporative diesel spray. A study on the mixture formation process of diesel spray was executed by the results of flow analysis in this study. Consequentially the large-scale vortex flow could be found in downstream spray and the formed vortex governs the mixture formation process in diesel spray.

• Journal of Energy Engineering
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• v.17 no.2
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• pp.47-53
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• 2008

The objective of this paper is to clarify the flow characteristic, velocity distribution, pressure loss, and other such fundamental data for the canister during loading and purging. The amount of gas that is loaded increases as the loading rate is decreased and the time increased, and the purging improves as the purge rate is increased. The hydrocarbons that are purged initially have a high concentration, and a large amount is purged. During loading and purging, the temperature initially increases and decreases drastically due to heat generation and heat loss.

• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.6
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• pp.85-93
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• 2001

Minimized canister flow restriction and maximized flow uniformity are desired to maximize a purge capability. With the impending ORVR(On Board Refueling Vapor Recovery) systems, the reduction of restriction and increase of flow uniformity in a carbon canister becomes even more critical to meet the stringent regulation. In this study, three-dimensional numerical simulations have been performed to investigate the three-dimensional internal flow patterns in a carbon canister during purge. The effects of the declined angle of the purge pipe and the number of partitions on the pressure drop and purge efficiency in a carbon packed bed are examined. Results show that the purge efficiency and space velocity distribution are affected in the upstream region of 40% of total canister bed by porosity of carbon granule and angle of purge pipe. It is also found that the purge efficiency decreases with increasing the number of partitions.

• Transactions of the Korean Society of Automotive Engineers
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• v.17 no.4
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• pp.133-138
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• 2009

The continued rise in the number of automobiles on the roads is prompting air pollution to emerge as a serious problem due to the harmful exhaust gas emissions throughout the world. Specifically, based on the exhaust gas regulation in North America represented by PZEV, the regulation on evaporative emission, which originates from the intake manifold system when the engine is stopped, is substantially being intensified. And the technology that can meet and satisfy these regulations has been needed. This study aimed to analyze and evaluate the butane working capacity (BWC) of HC adsorption filter according to the shape of it, which was developed to reduce evaporative emission, and the effect of HC adsorption filter on the engine performance. As a results, HC adsorption filter of the plate type, which was improved compared to that of the corrugated type and also became thinner, indicates higher absorption performance compared to the corrugated one. The absorption performance of the honeycomb type, derived from improving the shape of plate type, is 33.5% higher than that of the corrugated type. However, there was no significant difference in engine performance in all shapes.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.33 no.6
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• pp.454-460
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• 2009

To analyze the mixture formation process of evaporating diesel spray is important for emissions reduction in actual engines. Then the effects of change in density of ambient gas on spray structure in high temperature and pressure field have been investigated in this study. The ambient gas density was changed from ${\rho}_a=5.0kg/m^3$ to ${\rho}_a=12.3kg/m^3$ with CVC(Constant Volume Chamber). Also, simulation study by modified KIVA-II code was conducted and compared with experimental results. The ambient temperature and injection pressure are kept as 700K and 72MPa, respectively. The images of liquid and vapor phase in the evaporating free spray were simultaneously taken by exciplex fluorescence method. As experimental results, with increasing ambient gas density, the tip penetration of the evaporating free spray decreases due to the increase in the drag force from ambient gas. The spatial structure of a diesel spray can be verified as 2-regions consisted of liquid with momentum decrease and vapor with large-scale vortex. The calculated results obtained by modified KIVA-II code show good agreements with experimental results.

• Journal of Korean Society for Atmospheric Environment
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• v.17 no.E3
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• pp.101-107
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• 2001

Source profiles were developed for a total of 45 volatile organic compounds (VOC) that can be emitted from gasoline evaporation. The gasoline samples of five major brands (for each season) were blended on the basis of the market share in Seoul area and analyzed by a GC-MS/FID system. In addition, we calculated gasoline evaporative compositions using the Raoult's law from the liquid gasoline compositions. The measured and estimated gasoline vapor compositions agree well each other. As a group, alkanes are the most abundant in the gasoline vapors profiles (77.4% on average), followed by alkenes (19.1%), and aromatics (1.7%). As a specie in gasoline vapor, i-pentane is the most abundant, followed by n-butane, n-pentane, i-butane, trans-and cis-2-butenes, 2-methyl-2-butene, and trans-and cis-2-pentenes . It was also seen that aromatic content was much lower in the vapor phase compositions. From the comparison between experimental and calculated compositions, we identified the fact that once the gasoline vapor composition is reliably constructed entirely from the measured gasoline composition and the Raoult's law calculations, the need for doing separate chemical analyses of the gasoline vapor can be reduced.

• International Journal of Automotive Technology
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• v.7 no.4
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• pp.407-413
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• 2006

The liquefied petroleum gas(LPG), mixture of propane and butane, has the potential to reduce toxic hydrocarbon emissions and inhibit ozone formation due to its chemical composition. Conventional mixer systems, however, have problems in meeting the future lower emission standards because of the difficulty in controlling air-fuel ratio precisely according to mileage tar accumulation. Liquid Phase LPG injection(LPLi) system has several advantages in more precise fuel metering and higher engine performance than those of the conventional mixer type. On the other hands, leakage problem of LPLi system at the injector tip is a main obstacle for meeting more stringent future emission regulations because these phenomena might cause excessive amount of THC emission during cold and hot restart phase. The main focus of this paper is the development of a leaked fuel recirculation system, which can eliminate the leaked fuel at the intake system with the activated carbon canister. Leaked fuel level was evaluated by using a fast response THC analyzer and gas chromatography. The result shows that THC concentration during cold and hot restart stage decreases by over 60%, and recirculation system is an effective method to meet the SULEV standard of the LPLi engine.