• Journal of KSNVE
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• v.8 no.1
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• pp.47-48
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• 1998

당사에서 생산하는 대형버스의 소음/진동 평가에 관한 현황으로서 평가기술이 승용차량에 비하여 현저하게 낙후하여 축적된 기술력은 없으며 소음/진동의 기본 측정을 수행하는 정도의 수준임을 우선 밝히고자 한다. 본고에서는 당사의 소음/진동 평가방식과 수립대책에 대해 말하고자 한다.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.4
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• pp.371-376
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• 2012

The experimental test was conducted for a heavy-duty DME bus in JE-05 exhaust gas test mode using a chassis dynamometer, exhaust gas analyzers, and a PM measurement system. The heavy-duty DME bus was not equipped with after-treatment systems such as DOC or DPF. The dynamic behavior, emission characteristics, and fuel economy of the bus were investigated with an 8.0-liter, 6-cylinder conventional diesel engine. The results showed that the dynamic behavior in DME mode was almost the same as in diesel mode. However, there was little difference among the two operation modes for $NO_x$ and CO emissions. THC emissions were lower for DME mode than for diesel mode. Also, the amount of PM emissions was remarkably lower than for the diesel mode because DME contains a greater amount of oxygen than diesel. The data showed that $CO_2$ emissions were almost similar in the two modes but fuel economy (calculated using heating value) was lower for DME mode than for diesel mode.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2006.10a
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• pp.127-128
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• 2006

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.6
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• pp.98-116
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• 2006

For the next two decades the civil aviation industry is expected to grow. Both Airbus and Boeing predict a delivery of almost 20,000 new Large Civil Aircraft (LCA). LCA is defined as a large civil jet aircraft with 100 seats or more. Airbus offers the Superjumbo, A380 (>555 seats), while Boeing presents the Dreamliner, B787 (200 – 300 seats). Their philosophies are very different. In the wake of B787, Airbus intends to offer a new aircraft, A350, as the competitor against B787, with the same engines developed for B787. The U.S. government pushed by Boeing, on the day of October 6, 2004, filed a suit against Airbus for wrongful subsidy to the World Trade Organization (WTO). A brief overview is given on the LCA development status in the world commercial aircraft market. Since there have been little changes in engine and avionics manufacturers in the LCA industry, the airframe area only is the object of this study. An analysis is carried out to find out the differences in development and marketing strategies of two major LCA manufacturers, Airbus and Boeing. The authors predict that Boeing will recapture its No. 1 position soon, while the leading edge in technology may be slipped away from Boeing.

• Aerospace Industry
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• v.68
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• pp.10-13
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• 1999

유럽의 유일한 국제합작 대형 민간 항공기 제작업체인 에어버스가 올해로 창립 30주년을 맞는다. 동사의 1998년 수주 금액은 보잉사와 필적하는 규모에 달했다. 동시에 본거지인 프랑스의 툴루즈에서는 지난 5월초에 전세계의 항공 평론가와 보도 관계자 등 약 90명을 초청하여 예년처럼 Technical Press Briefing을 열고 동사의 현황과 전망 그리고 기업전략등이 소개되었다.

• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.6
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• pp.148-154
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• 1997

The safety problems of buses have been arisen due to the increasing of road traffic. Occupant injuries are always possible in the rollover accident and the frontal impact. Thus the structure of bus should have sufficient strength to protect passengers under accidental loads. ECE(Economic Commission for Europe) regulation No.66 prescribes that the superstructure of the vehicle shall be sufficient strength for passengers' surviving and the residual space shall be preserved in the passenger compartment during and after the standard rollover accident situation. Rollover test and simulation on a large-sized bus was completed according to the regulation. The coordinates of the points on the bus were measured by photogrammetry system. The rollover situation was revived by structural crashes simulation software, PAM-CRASH, and it was checked that the structure still complied with the requirements of residual space during rollover situation. The residual space was preserved during rollover, so it was proved that the structure of the investigated bus had much probability of survival in rollover accidents.

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

• Transactions of the Korean Society of Automotive Engineers
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• v.18 no.6
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• pp.138-144
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• 2010

If the vibration is occurred in a large-sized bus roof, it makes people annoying and complaining the quality of a large-sized bus. So in design stage, it must be considered. To assess vibration at the roof which is equipped with air conditioner in design stage, finite element model is constructed. Computer simulation analysis and experimental method are performed. The dynamic characteristics of the large-sized bus are found by using eigenvalue method. It is related with dynamic behavior. The running conditions of a large-sized bus are velocity and road condition which followed experimental conditions. And the frequency response of a large-sized bus is well correlated with analysis result. Modal participation method is used for finding major modes at each peak. Using this method, we found that front and rear suspension system, engine mounting system and roof structure are the major reasons of the roof vibration. To reduce vibration level of roof in a large-sized bus, spring stiffness of front and rear suspension system, spring stiffness of engine mounting system and roof structure are properly combined. From this study, the vibration characteristics of the roof structure of a large-sized bus can be to a satisfactory level.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.18 no.2
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• pp.1-11
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• 2019

The accident of mass transit such as a bus could draw the large casualties and this induces social and economic losses. Recently, severe bus accidents caused by tiredness and inattention of bus drivers occurred and those lead to growing interest in bus accidents and the drivers' work environment. Therefore, this study analyzes the accident based on the work environment of bus drivers and route-bus categories. For the research, this study collected digital tachograph data and the bus company information for 271 domestic bus companies in 2017 and used ANOVA test and chi-square test as statistical methodologies. As a result, we figured out there are statistically significant differences in the accident according to the working environments. Especially, the present study confirmed the intracity bus with working every other day has the most frequent accidents. We expect that the results of this study be used as foundations for the improvement of working conditions to reduce route-bus accidents in the future.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.2
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• pp.126-133
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• 2003

The aerodynamic characteristics of automobiles have received substantial interest recently. Detailed knowledge of the vehicle aerodynamics is essential to improve fuel efficiency and enhance stability at high-speed cruising. In this study, a numerical simulation has been carried out for three-dimensional turbulent flows around a commercial bus body. Also, the effect of rear-spoiler attached at rear end of bus body was investigated. The Wavier-Stokes equation is solved with SIMPLE method in general curvilinear coordinates system. RNG $k-\varepsilon$ turbulence model with the MARS scheme was used for the evaluating aerodynamic forces, velocity and pressure distribution. The results showed details of the three-dimensional wake flow in the immediate rear of bus body and the effect of rear-spoiler on the wake structure. A maximum of 14% reduction in drag coefficient was achieved for a model with a rear-spoiler.