• Journal of the Korean Society of Industry Convergence
• /
• v.25 no.6_2
• /
• pp.1111-1117
• /
• 2022

Recently, interest in the circular economy has emerged in the industry. As a result, interest in Re-manufacturing, which makes old equipment similar to new products, is growing. In the machine tool industry with many aging equipment, the Re-manufacturing industry is essential, and among them, research on the performance improvement of gear type oil pumps was conducted. The purpose was to achieve the target performance of flow rate and volume efficiency by changing the shape of the gear pump housing clearance and inlet/outlet, and Computational Fluid Analysis and Central Composite Design were conducted using ANSYS CFX 2022 R2 and MINITAB®. The level of each determined factor was determined. 20 design points were derived, and the Flow Rate at each design point was calculated, and the Theoretical Flow Rate was calculated to obtain Volumetric Efficiency. The optimal design point was obtained when the Flow Rate was 140 lpm and the Volumetric Efficiency was maximum, the optimal design point was obtained when both were maximum, and the Surface Plot for each factor was obtained to identify the tendency.

• International Journal of Automotive Technology
• /
• v.7 no.4
• /
• pp.441-448
• /
• 2006

In-cylinder flows such as tumble and swirl play an important role on the engine combustion efficiencies and emission formations. The tumble flow, which is dominant in current high performance gasoline engines, is able to effect fuel consumptions and emissions under a partial load condition in addition to the volumetric efficiency under a wide open throttle condition. Therefore, it is important to optimize the tumble ratio of a gasoline engine for better fuel economy, lower emissions, and maximum volumetric efficiency. First step for optimizing a tumble ratio is to measure a tumble ratio accurately. For a tumble ratio measurement, many different methods have been developed and used such as steady flow rig, PIV, PTV, and LDV. However, it is not well known about the relations among the measured tumble ratios using different methods. The purpose of this research is to correlate the tumble ratios measured using three different methods and find out merits and demerits of each measurement method. In this research the tumble flow was measured, compared, and correlated using three different measurement methods at the same engine: steady flow rig; 2-dimensional PIV; and 3-dimensional PTV water flow rig.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2004.11a
• /
• pp.253-260
• /
• 2004

In these days, 8000TEU container ship service launches in shipping service at latest based on the economy of scale, unit cast related with ship operation on ocean decreases in proportion to increase of ship scale and mega ship over 10,000TEU is on planning. This paper is analyzed the economic efficiency for reduction qf calling port in the operation cost, port chnrge, feeder cost, etc by an empirical analysis.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.3 no.2
• /
• pp.48-55
• /
• 1999

Performance analysis of a 50KW turbo-generator gas turbine engine with a recuperator was studied. Recuperated cycle has been employed to meet maximum fuel economy and ultra low emissions especially for military and vehicular engines. From thermodynamic stand point, it is known that recuperative cycle can contribute most to enhance thermal cycle efficiency for the Pressure ratios under 10 and of comparatively low turbine inlet temperature. Efficiency of a simple cycle with a recuperator increases relatively about 30% than without one at effectiveness of 0.5. Pressure losses in the heat exchanger less than 5.2% is considered in the design process. A tubular type heat exchanger is selected for this particular engine because it can provide simple construction as well as structural sturdiness and excellent leak tightness.

• Journal of the Korean Ceramic Society
• /
• v.46 no.1
• /
• pp.47-52
• /
• 2009

Lime paint surpassing others in execution efficiency, anti-bacterial, anti-mold and small quantity emission of VOCs(Volatile Organic Compounds) characteristics was developed using a limestone as raw materials. The lime paint prepared by mixing slaked lime($37{\sim}40\;wt%$), PVA:EVA(9 wt%:1 wt%), talc(23 wt%), $TiO_2$(14 wt%), zeolite (3 wt%), antifoaming agent(5 wt%), wetting agent (5 wt%) was indicated over 99.8% of anti-bacterial and anti-mold characteristics. Also, the environment-friendly function of the lime paint was confirmed by detection of small amount of TVOCs($0.01\;mg/m^2h$) and formaldehyde($0.008\;mg/m^2h$). Execution efficiency, economy-and environment-friendly characteristics of this lime paint can make up for defects of established paints. And, it also presents the advantage of a limestone as high value added materials.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.8 no.12
• /
• pp.1857-1864
• /
• 2013

In 21 century, it is difficult to define the limit of home automation, Recently, based on the advanced digital communication technology and necessity, The scope of the home automation has widened to home energy management, integrated reading of home and home health care etc. beyond the existing home automation. However, those methodologies reduce the efficiency and economy, and make it harder to realize a compact home automation because those methodologies are proposed independently without a unified standard. Therefore, this paper investigates and analyzes these methodologies, and then proposes an advanced home automation system that enables a compact design and improves the efficiency and economics of the home automation system based on the analyzed result.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.21 no.4
• /
• pp.83-88
• /
• 2013

Recently, PCCI (premixed charge compression ignition) combustion is studied to reduce both NOx and PM because of homogeneous mixture formation and lower combustion temperature. It has also merit of increasing thermal efficiency owing to better air-fuel mixure. However, it is well known that PCCI combustion has a weakness in fuel economy because PCCI combustion tends to start before TDC. Therefore, it is necessary to find an optimal conditions for PCCI combustion which maintains reduction of NOx, PM and increase of thermal efficiency. In this study, pPCCI combustion was realized by adding early injection strategy to a conventional diesel engine. In addition, the characteristics of pPCCI combustion was analized by comparing conventional diesel injection strategy. The results show that NOx and PM per power in pPCCI combution were reduced compared to a conventional diesel combustion.

• 한국신재생에너지학회:학술대회논문집
• /
• 2005.11a
• /
• pp.541-544
• /
• 2005

This study presents the integrated modeling approach to simulate the proton exchange membrane (PEM) fuel cell system for vehicle application. The fuel cell system consisting of stack and balance of plant (BOP) was simulated with MATLAB/Simulink environment to estimate the maximum system power and investigate the effect of BOP component sizing on system performance and efficiency. The PEM fuel cell stack model was established by using a semi-empirical modeling. To maximize the net efficiency of fuel cel1 system, multi-variable optimization code was adopted. Using this method the optimized operating values were obtained according to various system net power levels. The fuel cell model established was co-linked to AVL CRUISE, a vehicle simulation package. Through the vehicle simulation software, the fuel economy of fuel cell powered electric vehicle for two types of driving cycles was presented and compared. It is expected that this study tan be effectively employed in the basic BOP component sizing and in establishing system operation map with respect to net power level of fuel cell system.

• Korean System Dynamics Review
• /
• v.11 no.2
• /
• pp.45-75
• /
• 2010

Today, the logistics industry has played a critical role in national economy activities. The low cost and high efficiency of the logistics industry are meaningful in the improvement of national competitiveness and the logistics industry. However, efficiency of logistics is lower than that of the United States and Japan since most quantities are processed in road transportation in Korea. With regard to this, existing studies expected a saving of social and environmental costs due to a decrease of road transportation as well as improvement of logistics productivity due to bulk transportation through activation of rail and costal transport. For the expectation, the existing multimodal transport systems should be improved first. Therefore it aimed to develop scenario-based simulation models of multimodal transport systems for decision makers in charge of improvement in the logistics area. For model development, this study utilized Thinking Process and System Dynamics(TP-SD) methodology.

• Journal of Advanced Navigation Technology
• /
• v.17 no.1
• /
• pp.132-141
• /
• 2013

In this paper, method using electric braking from stop area to high-speed area was presented in order to improve air-brake. And electric braking method can be improved environmental problems, efficiency, economy, etc. Method for electrical complete braking are two ways that method of inserting series resistance between the motor and the inverter, and method of inverter output voltage increase. In this paper, use series resistance insert method because economical and easy to apply. In addition, Series resistor is used short circuit method for reduce the power loss. In improved efficiency and the laboratory environment for secure braking, resistance insert method and inverter output voltage increase method showed same characteristics in all areas.