• Journal of IKEEE
• /
• v.24 no.2
• /
• pp.610-618
• /
• 2020

This paper presents the modeling of hybrid railway vehicles with hydrogen Fuel-Cells (FCs)/battery using a rule-based algorithm. The driving power of traction system is determined with the speed-torque curve by operation area of the electric machine and the electrical systems are modeled. The demanded power of electrical systems is set with the energy management system (EMS). The consumption of hydrogen is effectively managed with the subdivided operation region depending on the state of charge (SOC). The validity of the modeling is verified using MATLAB/Simulink.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.25 no.9
• /
• pp.1193-1200
• /
• 2001

There are many regulation test methods to be related with engine emissions such as CVS-75, D-13, ECE-15 modes and so on. Most of these modes are consisted of lots of transient conditions that have rapid acceleration, deceleration and cranking modes. In this experimental research, the engine characteristics of cranking, accelerating and power output in a S.I. engine were studied to compare with neat gasoline and alternative fuels of M30 (methanol 30%, aromatic series 32%, non-aromatic 38%) and M50 (methanol 50%, aromatic 30%, non-aromatic 20%) for performance and exhaust emissions. The results show that reformulated methanol fuels are better emissions reduction of 15.7% over than that of neat gasoline fuel especially in HC and CO emissions at cranking mode. And the accelerating performances coincide with the results of distillation curve. CO concentration for M50 fuel is varied in a just little for the condition of slow acceleration. At wide-open throttle condition, brake specific energy consumption of reformulated fuels is increased and thermal efficiency is some what lower than that of gasoline fuel.

• Proceedings of the KIEE Conference
• /
• 2006.07a
• /
• pp.521-522
• /
• 2006

This paper calculates co-generation generating capacity for the electric supply and demand. CHP is applied to SCM(Screening Curve Method) to calculate CHP generating capacity On the other hand, small co-generation is applied to potential area conversing small co-generation generating capacity considering economic analysis and useful life. these methods executed project scheduled to construction plan. Accordingly, EES(Expected Energy Served), Fuel type consumption and CO2 effects is analyzed by Booth-Baleriaux and data

• Journal of Welding and Joining
• /
• v.18 no.2
• /
• pp.239-239
• /
• 2000

Automobile manufacturers have employed resistance spot welding(RSW) to join steel sheets for structural rigidity o automobile body. Driven by the need to reduce weight and fuel consumption, car companies have been evaluating aluminum intensive vehicles(AIVs) as a way to reduce vehicle weight without downsizing. During the transition from all steel-construction vehicle body to aluminum intensive body, joining aluminum to steel sheets emerges as a serious contender in automobile body. This paper deals with application of transition material to RSW aluminum to steel. Placing transition material insert between the aluminum/steel interface was found very effective to overcome incompatibility between aluminum and steel. Use of transition insert allows for two separate weld muggets to be formed in their respective aluminum/ aluminum and steel/ steel interfaces. This RSW process was monitored with the aid of dynamic resistance sampling. Typical patterns in sampled dynamic resistance curves indicated formation of sound nugget. (Received February 28, 2000)

• Journal of Welding and Joining
• /
• v.18 no.2
• /
• pp.112-118
• /
• 2000

Automobile manufacturers have employed resistance spot welding(RSW) to join steel sheets for structural rigidity of automobile body. Driven by the need to reduce weight and fuel consumption, car companies have been evaluating aluminum intensive vehicles(AIVs) as a way to reduce vehicle weight without downsizing. During the transition from all steel-construction vehicle body to aluminum intensive body, joining aluminum to steel sheets emerges as a serious contender in automobile body. This paper deals with application of transition material to RSW aluminum to steel. Placing transition material insert between the aluminum/steel interface was found very effective to overcome incompatibility between aluminum and steel. Use of transition insert allows for two separate weld nuggets to be formal in their respective aluminum/aluminum and steel/steel interfaces. This RSW process was monitored with the aid of dynamic resistance sampling. Typical patterns in sampled dynamic resistance curves indicated formation of sound nugget.

• Journal of Energy Engineering
• /
• v.16 no.1 s.49
• /
• pp.22-31
• /
• 2007

This paper addresses methodology in order to consider CHP (Combined Heat and Power) capacity in the Basic Plan of Long Term Electricity Supply & Demand and presents effects on it. The method performs state in extent that do not change maximum in the Basic Plan of Long Term Electricity Supply & Demand. For analysis that occurs some advantage this method compares with Basic Plan of Long Term Electricity Supply & Demand. It includes EES (Expected Energy Served), Fuel consumption, amount of $CO_{2}$ emission reduction.

• Environmental and Resource Economics Review
• /
• v.28 no.4
• /
• pp.583-615
• /
• 2019

This paper investigates the level of decoupling between greenhouse gas emissions and economic growth in Korea. Despite previous studies mainly stressed the existence of the Environmental Kuznets Curve, the lack of investigations in the level of decoupling constraints further policy suggestions. This study analyzes the level of decoupling in the short- and long-term, focusing on short-term volatility of GHG emissions income elasticity. In the long run, there is no decoupling in Korea because a robust causal relationship exists between GHGs, GDP, and fossil fuels. However, the short-term volatility is clearly identified under the long-term equilibrium(coupling), indicating there is the relative decoupling in the short run. The results show that fossil fuel dependence is a significant factor that increases short-term volatility(decoupling) and breaks the causal link(coupling) between GHGs and GDP.

• International Journal of Highway Engineering
• /
• v.17 no.3
• /
• pp.49-58
• /
• 2015

PURPOSES : The use of environmentally friendly construction methods has been recently encouraged to reduce fuel consumption and the effects of global warming. For this purpose, the roller compacted concrete pavement (RCCP) construction method has been developed. RCCP is more environmentally friendly and economically efficient than general concrete by reducing the amount of CO2 generated through the application of a smaller amount of cement. RCCP has a number of advantages such as an easy construction method, low cost, high structural hydration performance, and aggregate interlocking. However, mix design standards and construction guidelines of RCCP are required for domestic application. In addition, a study on aggregate selection, which has an effect on the characteristics of RCCP, is necessary owing to a limited number of researches. Thus, the aggregate effect on the performance of RCCP in securing the required strength and workability was evaluated in consideration of domestic construction. METHODS : Sand and coarse aggregates of both 19mm and 13mm in maximum size were used in this study. Four types of aggregate gradations (s/a = 30%, 58%, and 70% for the sand and coarse aggregate of 19mm in maximum size, and s/a = 50% for a combination of the three types of aggregates) were set up to investigate the effects of the PCA band on the RCC characteristics. The conditions of s/a = 30% and 70% were evaluated to check the gradation effect outside of the recommended band. The conditions of s/a = 58% and 50% were used because they are the optimum combination of the two and three types of aggregates, respectively. RCCP gradation band was suggested gradation with a proper construction method of RCCP by synthetically comparing and analyzing the correlation of optimum water content, maximum dry density, and strength of requirements through its consistency and compaction test. RESULTS : The lower and upper limit lines are insufficient to secure a relatively strong development and workability compared to an aggregate gradation in the RCCP gradation band region. On the other hand, the line in the RCCP gradation band and the 0.45 power curve in the RCCP gradation band region were satisfactory, ensuring the required strength and workability. CONCLUSIONS : The suitable aggregate gradation on RCCP process should meet the RCCP gradation band area; however, fine particles passing through a #60 sieve do not need to be within the recommended gradation band because the influence of this region on such fine particles is small.