• Journal of the Korean Society of Safety
• /
• v.23 no.5
• /
• pp.15-21
• /
• 2008

The bus using compressed natural gas(CNG) trend to be extended in use internationally as optimal counter-plan for reducing discharge gas of light oil due to high concern about environment. But, Composit pressure vessels(CPV) to be equipped with CNG bus is always involved in the point that safety accidents happen due to having compressed natural gas. In this report, we analysis the cause of CPV bursting accident by reviewing design and manufacture factor and suggest preventive measure through this case.

• Journal of the Korean Professional Engineers Association
• /
• v.34 no.3
• /
• pp.28-32
• /
• 2001

Using the CNG(compressed natural gas) and LPG(liquified petroleum gas) as the automotive fuel will be expanded because of their clean effect to the environmental air qualify. But these programs of gas using expansion would have a difficulty due to public consideration of gas utilities as a big hazard. The Ministry of Environment has an ambitious plan to substitute more than 25,000 buses with CNG and ensure more than 200 CNG refueling stations as well by the year of 2007. However, it is very difficult to establish new CNG and LPG refueling stations because of expanded safety distance than ever before by several major explosion accidents.

• Journal of the Korean Institute of Gas
• /
• v.16 no.4
• /
• pp.1-7
• /
• 2012

Systematic safety research by Korea Government has been made to enhance the safety of CNG (compressed natural gas) vehicles since the burst of compressed cylinder of an urban bus in August 9, 2010. This article summarizes some major activities to ensure the safety of CNG vehicles, which covers review of regulation, safety management system including standard of inspection and certification, and training program of inspectors and car mechanics. Specifically, the followings were reviewed; type of CNG cylinder, location of CNG cylinder, material and type of fuel line and vent line, modification of pipeline connection, installation of gas detector, installation of emergency shutdown valve, installation of protecting cover for cylinder, obligations for CNG vehicle filling station. improving periodical inspection, routine test on gas vehicles, training program for engaged in gas vehicles, and designation of safety manager for CNG bus company. This paper suggests how to improve safety of CNG vehicles as a result of review of above mentioned check items.

• Journal of the Korean Institute of Gas
• /
• v.15 no.1
• /
• pp.9-14
• /
• 2011

Heavy duty diesel engine has relatively small portion of whole vehicles due to long drive distance and large engine displacement, but largely influences atmosphere environment. City buses changed to CNG (Compressed Natural Gas) bus with Korea-Japan Worldcup. Heavy duty truck and intercity bus, however, were impossible to use CNG because those kinds of vehicles had long drive distance and CNG station was installed mainly at the around of the bus garage of city. Insulation container storing the natural gas as a liquid makes heavy duty truck and intercity bus possible to use the natural gas. Drive using diesel is possible where is hard to recharge the gas. With LNG (Liquefied Natural Gas), the dependence on oil is largely decreased, PM (Particulate Matter) and NOx which is chronic disadvantage of diesel is remarkably reduced and finally $CO_2$, the representative green house gas, is reduced over 10%.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.8 no.2
• /
• pp.83-89
• /
• 2009

An air-fuel ratio control is essential in reducing hazardous exhaust emissions from a compressed natural gas(CNG) engine, and can be accomplished by accurate control of gas injection flow. In this study, theoretical research was conducted on injection characteristics of a solenoid gas injector, and injection experiments for calibration and analysis were performed. Various factors for gas injection flow such as injection pressure, gas temperature, and supply voltage are studied. A dynamic flow equation of the natural gas was proposed on the basis of flow dynamics theories and results of the injection experiment. The verification of the dynamic flow equation of the solenoid injector was carried out with a large CNG-engine applied to an urban bus. Air-fuel ratio control experiments were conducted in both steady and transient state. Results of injection experiments for the solenoid injector and the CNG-engine was proved the control method proposed herein to be effective.

• Proceedings of the KSR Conference
• /
• 2007.05a
• /
• pp.911-915
• /
• 2007

This paper deal with the design concept of traction motor for Bimodal low floor vehicles that are CNG(Compressed Natural Gas) hybrid bus and Fuel-cell bus. The design concept of the traction motor is studied in terms of electrical characteristics and mechanical construction. Finally, this paper introduces the characteristic of the traction motor for low floor vehicles which are applied in the world, and mentioned the detail design concept of traction motor.

• Journal of the Korean Institute of Gas
• /
• v.22 no.5
• /
• pp.114-123
• /
• 2018

As recognizing the necessity of eco-friendly vehicles in order to reduce air pollution from road sector, Korean government has established and implemented a promotion policy which is encouraging the public transportation companies to purchase CNG buses in replacing diesel buses since 2000s. With CNG bus promotion policy, the number of CNG buses had been increased on the road of metropolitan area and big cities. However, increasing rate of CNG buses had been fluctuated between the decrease and the increase since year 2014. In this study, the impact of fuel cost competitiveness between diesel and CNG on CNG bus increasing volume was testified by simple regression, which was only assumed by precedent research on the CNG promotion policy. And this study suggested the necessity of harmonization among the related policies conducted by related Ministries. Eventually this study should contribute to enhance the validity of CNG bus promotion policy. And it is expected that Korean government should apply the new policy suggestion of this study in the establishment of government's promotion policy on LNG cargo trucks and Zero Emission Vehicles in the future.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.17 no.9
• /
• pp.133-140
• /
• 2016

The Ministry of Land, Infrastructure and Transport has introduced low-floor buses, which are convenient for passengers getting on and off the bus and for the handicapped. The standard bus model is 11 m long and uses compressed natural gas (CNG). However, this model has drawbacks in narrow rural road conditions such as those in farming and fishing villages and mountainous areas, as well as difficulty in refueling since CNG facilities are not readily available. In this study, running resistance values were obtained by coasting performance tests on actual roads using a Tata Daewoo LF-40 model with three different weight conditions: curb vehicle weight (CVW), half vehicle weight (HVW), and gross vehicle weight (GVW).The test methods include WHVC, NIER-06, and constant-speed driving at 60 km/h. These tests were used to measure the fuel economy of vehicles other than the target vehicles to obtain the combined fuel economy. The energy efficiency was highest in the case of CVW. In the WHVC mode, the fuel consumption rates of HVW and GVW were typically 3.5% and 12% higher than that of CVW, respectively. In constant-speed driving, the fuel efficiency of HVW was higher than that of CVW. Further research is required to analyze the exhaust gas data.

• Journal of Trauma and Injury
• /
• v.24 no.2
• /
• pp.129-135
• /
• 2011

Purpose: During August 2010, a natural gas fuel cylinder on a bus exploded in downtown Seoul, injuring 20 citizens. This kind of blast injury has never been reported in Korea before. Thus, the goal of this study was to review the clinical features of these victims to help physicians manage similar cases and to understand the risk factors associated with blast injuries in everyday life. Methods: Twenty (20) victims who visited nearby emergency departments, and 3 peoples left hospital without care. Seventeen (17) victims were included in this study, and the following factors were investigated: age, sex, type of hospital, diagnosis of injury, injury mechanism, position of victim (in-bus/out of bus), classification of injury severity with START (simple triage and rapid treatment), and classification of injury according to the mechanism of the blast injury. Results: The victims included 8 males (47%), 9 females (53%). The mean age was $37.5{\pm}12$. Thirteen (13) victims were transferred to two tertiary hospitals, and 4 were transferred to two secondary hospitals. The types of injury were 3 fractures, 2 ligaments injuries, 6 contusions, 4 abrasions, and 3 open wounds (one of them was combined fracture). According to START classification, 17 victims were 1 immediate, 11 minor, 5 delayed, and no death. Classifications according to the mechanism of the blast injury were 1 primary injury, 6 secondary injuries (2 of them combined other mechanism), 3 tertiary injuries and 9 quaternary injuries. Conclusion: Trauma care physicians should be familiar with not only the specific types of injuries from blast accidents, but also the potential accidents that may occur in public facilities.

• Clean Technology
• /
• v.24 no.3
• /
• pp.166-174
• /
• 2018

Since particulate matter has high impacts on human health and everyday life, the dual fuel systems utilizing diesel and compressed natural gas have been developed to improve the environmental performance of diesel vehicles. The objective of this study is to estimate the economic feasibility of the dual fuel system based on real operating data of dual fuel buses and diesel buses. The system is economically feasible if the annual mileage of the dual bus is higher than 30,000 km, or if the unit fuel price of diesel is higher than that of CNG by 408 won. The uncertainty analysis results show that the economic feasibility of the system is probabilistically high, regardless of the variability of input data such as mileage and unit prices for the fuels. The sensitivity analysis results show that diesel and CNG prices are the highest contributor to the net present value of the system. Based on these results, economic incentives are suggested to disseminate the systems. This study would provide valuable economic information for bus business industry and policy maker to help make decisions for applying and disseminating the dual fuel systems to mitigate particulate matter problems.