• Environmental Analysis Health and Toxicology
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• v.21 no.2 s.53
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• pp.127-138
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• 2006

In urban areas, diesel exhaust particles (DEP) are probably a major component of particulate matters, especially in Korea where drive many diesel vehicles. The aim of this study was to investigate genotoxic effects of DEP using single ceil gel electrophoresis. In order to evaluate the mechanisms of DEP genotoxicity, the rat microsome mediated and DNA repair enzyme treated comet assays together with conventional comet assay were performed. Total diesel particles (DEPT) was collected without site fractionation from diesel engine bus and dichloromethane extract was obtained. The organic extract of DEPT revealed DNA damage itself in NIH/3T3 cells. The level of DNA breaks plus oxidative DNA lesions and microsome mediated DNA damage was assessed by modified single cell gel eletrophoresis. DEPT was able to induce oxidative DNA damage as well as microsome mediated DNA damage. Vitamin C as an model antioxidant reduced DNA damage in endonuclase III treated comet assay. One of flavonoid, galangin as a CYP1A1 inhibitor. reduced DNA damage in the presence of S-9 mixture. $DEP_T$ is the sources of oxidative stress, but antioxidants can significantly reduce oxidative DNA dmage. And $DEP_T$ may contain indirect mutagens which can be inhibited by CYP1A1 inhibitors. The ethanol extracts of the mixed vegetables (BV) or the mixed fruits (BF) were evaluated for their in vitro antigenotoxic effects. BV and BF showed potent Inhibitory effects against DEPT induced DNA damage with oxidative DNA lesions and in the prescence of S-9 mixture. These results indicate that BV and BF could prevent cellular DNA damage by inhibiting oxidative stress and suppressing cytochrome P4501A1 in cell culture.

• Transactions of the Korean hydrogen and new energy society
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• v.23 no.6
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• pp.634-639
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• 2012

The contribution levels of emissions from the heavy-duty vehicles have been continuously increased. Among the exhaust emissions, NOx (nitric oxides) have a ratio of 73.2% and particle matters have a proportion of 61.8% in the heavy-duty vehicles. Also, natural gas vehicles have the 78.9% of total registered local buses in Korea. Therefore, the investigation on emission characteristics of heavy-duty vehicles using CNG and diesel fuel according to the various driving cycles was carried out in this study. In order to analyze the emission characteristics, the five kinds of buses by using CNG and diesel fuels with a after-treatment devices (DPF, p-DPF) was used and five test driving schedules were applied for analysis of emission characteristics in a chassis dynamometer. To analyze the exhaust emission, the exhaust emission and PM analyzers were used. From this study, it is revealed that diesel buses with after-treatment had reduced emission of CO, HC, PM but NOx. Also, NMHC emission of CNG bus have a higher level and NOx level was similar with diesel buses. In addition, emissions in NIER06 with slow average speed shows lowest levels compared to other test modes.

• Journal of ILASS-Korea
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• v.29 no.2
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• pp.68-74
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• 2024

As awareness of environmental pollution problems increases worldwide, interest in air pollutants is increasing. In particular, NOx and PM, which are major pollutants in diesel vehicles, are contributing significantly to emissions. As a result, its importance is increasing. In this study, based on research results applied to large diesel vehicles, the problem of natural regeneration caused by low exhaust gas temperature during low speed and low load operation is solved by applying a complex regeneration DPF that is not affected by temperature conditions to small diesel vehicles. The feasibility of application to small diesel vehicles was reviewed by measuring the emission reduction efficiency. As a result of the engine test, the power reduction rate and fuel consumption rate before and after device installation under full load conditions were 2.9% decrease and 3.5% increase, respectively, satisfying the standard for a 5% reduction, and as a result of the regeneration equilibrium temperature (BPT) test, the regeneration temperature was 310℃. appeared at the level. The reduction efficiency test results for the actual vehicle durability test equipment showed 97.3% PM, 51.0% CO, and 31.1% HC, while the city commuter vehicle had PM 97.5%, CO 61.7%, HC 40.0%, and the school bus vehicle had PM 96.8%, CO 44.4%, HC 34.3%, and low-speed logistics vehicles showed a reduction efficiency of 98.2% for PM, 36.0% for CO, and 45.7% for HC. Based on the results of this study, in the future, it is necessary to secure DPF technology suitable for all vehicle types through actual vehicle application research on temperature condition-insensitive composite regenerative DPF for medium-sized vehicles.

• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.1388-1390
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• 2002

Hybrid power system has a power balanced controller to equilibrate generation power with a load demand and it is composed of DC bus-type power systems. And all of power generators in hybrid power system can be equivalent to current-source characteristics. So this paper discusses power balance control for photovoltaic/wind/diesel hybrid power system. And through the results of simulation, the proposed scheme was verified.

• Journal of Mechanical Science and Technology
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• v.18 no.11
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• pp.2049-2057
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• 2004

In this study, the combustion characteristics and durability of a diesel engine using emulsified fuel was investigated. Water was used in oil type emulsified fuel. In order to understand the effect of emulsified fuel in a wide range of engine running conditions, D-13 mode was selected as a test condition, and a durability test was included to understand the long-term effect of water. Combustion pressure in a cylinder, exhaust emissions, specific fuel consumption, sound level and maximum torque were measured. NOx and PM were simultaneously reduced and the specific fuel consumption was increased and decreased at low and high loads, respectively. There was no trouble and any damage on the parts of the cylinder during a 500 hour durability test.

• Transactions of the Korean Society of Automotive Engineers
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• v.4 no.1
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• pp.1-15
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• 1996

This study is concerned with the property changes(chemical and mechanical) of the used oil in diesel engine, which were sampled from a test engine with dynamometer and various cars. The properties of oil are TAN, viscosity, oxidation, ZDTP depletion factor and etc. Also the relation between the change of chemical and antiwear property of used oil was strongly related to ZDTP depletion factor as wall as the change of TAN(total acid number), sulfation and pentan unsoluble contents which were reated to the formation of protect film in sliding area. The oil used in pick-up(small) truck engine was deteriorated within the shortest distance than that of other cars. The antiwear property of used oil was decreased sharply as the running distance were over 5,000km. The oil used to mini bus was the least to deteriorate of properities for the funning distance.

• Journal of the Korean Institute of Gas
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• v.21 no.6
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• pp.70-80
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• 2017

According with annual report by the OECD (Organization for Economic Co-operation and Development), South Korea is at the top of the list of countries with bad air pollution (fine dust particles) and the South Korean government announced the cause to be due to the particle emissions of large and old diesel vehicles. To solve this issue, the government (jointly with related ministries), promoted the "Special Measures for Comprehensive Fine Dust Management Program" as a way to improve environmental pollution by reducing the overall output of fine dust particles emitted by public vehicles. The measure implemented a gas subsidy system to convert eco-friendly vehicles of city and chartered buses throughout the country. In this study, we take a look at the economical evaluation, comparison and analysis of the conversion of diesel vehicles to natural gas (CNG) vehicles. This report represent the basis for the need to expand the funds of the subsidy program and reviews the feasibility of the policy by taking into consideration the social and economical benefits and the effect in the environment when converting diesel fuel to natural gas vehicles through the type-specific fuel conversion scenarios.

• Journal of ILASS-Korea
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• v.29 no.2
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• pp.53-59
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• 2024

Cars are one of the main causes of air pollution in large cities, and 34.6% of domestic air pollution emissions come from mobile sources, of which cars account for 69.6%. In particular, the importance of nitrogen oxides (NOx) and particulate matter (PM), which are major pollutants in diesel vehicles, is increasing due to their high contribution to emissions. Therefore, in this study, the problem of natural regeneration caused by low exhaust gas temperature during low speed and low load operation was solved by applying a complex regeneration DPF that is not affected by temperature conditions to large diesel vehicles with higher driving time and engine displacement than small and medium-sized vehicles. And the feasibility of application to large diesel vehicles was reviewed by measuring the emission reduction efficiency. As a result of the reduction efficiency test on the actual vehicle durability product, PM showed a reduction efficiency of 84% to 86%, and the reduction efficiency of gaseous substances showed a high reduction efficiency of over 90%. The actual vehicle applicability test was completed with three driving patterns: village bus vehicle, police car, and road-going construction equipment vehicle, and no device problems occurred until the end of the test. Both load and no-load smoke measurement results showed a smoke reduction efficiency of over 96%.

• Fire Science and Engineering
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• v.18 no.2
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• pp.57-67
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• 2004

The results of the risk assessing on general buses, consisting mainly of diesel-fueled buses, show that the frequency of the instantaneous release is 1.4${\times}$10$^{-3}$ /bus/year, from which the probability of the formation of fireball as a sub event becomes 1.7${\times}$104, and show that the leakage from the CNG-fueled buses is 0.002 event/year. Also, the frequency of gradual release due to a crack is estimated at 3.7${\times}$10$^{-3}$ /buses/year, and a subsequent probability at which this could lead to a jet flame as a sub event is 1.2${\times}$10$^{-3}$ This corresponds to 0.04event/year for the CNG-fueled buses. Dividing all the fired casualties by the running distance of diesel-fueled buses, the risk is 0.091 fire fatalities per 100-million miles. And the total fire risk fur CNG buses is approximately 0.17 per 100-million miles of travel. This means that CNG buses is twice or more dangerous than diesel buses. After all CNG buses are more susceptible to the major fires. In the aspect of the reliability of this study, generic models and the failure data used in assessing the risks of CNG buses are appropriate. However, more accurate physics-based models and databases should be supplemented with this study to provide the better results.

• Environmental Analysis Health and Toxicology
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• v.19 no.4
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• pp.335-344
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• 2004

Diesel exhaust particle (<2.5 ${\mu}{\textrm}{m}$, DEP$_{2.5}$) is known to be probarbly carcinogenic (IARC group 2A). DEP$_{2.5}$ contains organic compounds such as polycyclicaromatic hydrocarbon (PAH), heterocyclic compounds, phenols, and nitroarenes. Reactive oxygen species (ROS) are generated by DEP$_{2.5}$ without any biological activation system. Therefore, an alternative mechanism by which DEP$_{2.5}$ could be carcinogenic is known by the generation of oxidative DNA damage. The aim of this study was to investigate genotoxic effects of DEP$_{2.5}$ using single cell gel electrophoresis. In order to evaluate the mechanisms of DEP$_{2.5}$ genotoxicity, the rat micro-some mediated and DNA repair enzyme treated comet assays together with routine comet assay were performed. DEP$_{2.5}$ was collected from diesel engine bus and dichloromethane extract was obtained. The organic extract of DEP$_{2.5}$ revealed DNA damage itself in NIH/3T3 cells. And it showed both oxidative and microsome mediated DNA damages. Vitamin C as an model antioxidant reduced DNA damage in endonuclase III treated comet assay. One of flavonoid, galangin as a CYP1A1 inhibitor reduced DNA damage in the presence of S-9 mixture. Our results show that DEP$_{2.5}$ are genotoxic and a great source of oxidative stress, but antioxidants can significantly reduce oxidative DNA damages. And DEP$_{2.5}$ may contain indirect mutagens which can be inhibited by CYP inhibitors.d by CYP inhibitors.