• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.10 no.4
• /
• pp.65-69
• /
• 2001

Research on the development of CNG dedicated engine that has important meaning both as a clean fuel and an alterna- tive energy to reduce the exhaust emission from diesel engine are actively going on these days. In this study, in order to present the direction and application of CNG engine, we tested the CNG engine performance experimented by changing the parameters such as ignition timing, equivalent ratio. The engine performance experimented by changing the parameters such as ignition timing, equivalent ratio. The engine performance and exhaust emission were measured by engine performance model at maximum load condition with increasing the rpm in the range of 1,000∼2,200rpm. Also, the testing engine was heavy-duty CNG dedicated engine with displacement of 11,050cc.

• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.12 no.6
• /
• pp.97-103
• /
• 2003

Currently, due to serious increase of pollution scones, lots of technology has been involved to reduce exhaust gas in diesel engine. But the amounts of exhaust gas can not be decreased somehow due to the increase of diesel vehicles. Moreover, emission standards of each counties are being stringent in advanced countries such as USA and Europe. In the near future, sulfur contents in fuel must be essentially reduced f3r health and environment because sulfur can basically reduce exhaust gas. Therefore, when will be applied to Bio-diesel and ULSD, they could reduce sulfur contents of fuel without aftertreatment and might conform the influence of engine performance, emission, smoke and fuel consumption.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 1998.03a
• /
• pp.304-309
• /
• 1998

In recent truck industry, ride quality improvement as well as payload capacity is a very important subject. In order to achieve this goal, it is necessary to study several sub-systems (powertrain, suspension, engine mount, exhaust, etc) of truck which are major components of vehicle. In this research, torsional vibration reduction method of 4$\times$2 truck powertrain is demonstrated by using computer simulation and experiment. First, truck powertrain is modeled as a vibration system and validity of developed model is verified by comparing free vibration results with experiment results. Second, Most key parameters which influence torsional resonance are examined utilizing mode analysis. Finally, frequency responses of truck powertrain are obtained and reduction counterplans of torsional vibration are suggested.

• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.13 no.6
• /
• pp.114-118
• /
• 2004

This research focused on the principle and the development of continuous regeneration DPF technology which was the best particulate matters removing technology of current existing technologies owing to its superior comparability and possible applicability. In addition, there were some discussions about the affecting engine parameters such as engine driving conditions and the amounts, velocity, temperature, pressure of exhaust emissions as well as sulfur contents and lubricants which were prerequisites to prevent poisoning effect on catalysts. The test was made on an 8000cc heavy-duty turbo diesel engine on which continuous regeneration DPF was in order to investigate regeneration characteristics of DPF and me performance under the condition of standard or 50ppm low sulphur diesel. Exhaust emissions, CO, HC, NOx PM were measured and compared under D-13 modes.

• 전기의세계
• /
• v.27 no.3
• /
• pp.54-58
• /
• 1978

정부의 중화학공업 육성시책에 힘입어 1976년과 1977년은 각 업체가 심각한 각축전을 벌린 해인 것같다. 1969년에 효성중공업이 154kV 급변압기 개발에 성공한 이래 수년간 독점해오던 초고압 변압기는 1976년 12원에 국제전기가, 1977년 1원에 쌍용전기가, 동년 7월에 대명제작소가 각각 시작품을 성공적으로 제작함으로써 독점시대의 막이 내려가고 치열한 경쟁체제로 돌입하게 됐다. 따라서 국내 수요보다 생산능력이 초과하게 되는 결과가 됐다. 효성중공업은 창원에 대단위 공장을 건설하고 최신시설과 대형 공작기계를 갖춤으로서 345kB 변압기 개발에 착수하였고 현대중공업, 현대양행이 중전기에 코오롱그룹이 국제전기의 경영에 각각 참가하였으며 이천전기는 일본 도시바전기와 합작하고 현대중공업과 현대양행이 참여함으로서 중전기기 분야는 전국시대를 맞는 감이며 치열한 경쟁을 앞으로 면치 못할 것같다.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 2002.10a
• /
• pp.99-103
• /
• 2002

A field test was peformed to estimate the thermal performance of the forced convection electric air heater by the experiment. Air temperature, flow rate and electrical power input were measured with the related measurement sensors, and acquisition methods for the measured data were studied to effectively estimate the thermal performance of the tested air heater. To determine the mean air temperature at the flow cross-section, measuring positions were chosen by considering the flow velocity profile and the equally divided cross-sectional area. From the experimental results, thermal efficiency is obtained as an indication of the tested electric air heater performance.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 2005.05a
• /
• pp.109-114
• /
• 2005

The large injection molded parts technology such as instrument panel, front and rear bumper are presented for a precision molding. Some lead time and cost are required to product these part from design to mass product. Recently, CAE is widely used in product design, mold design and analysis of molding conditions to reduce time and cost. The optimal molding conditions can be obtained by DOE(Design of Experiment). The optimal design applications with CAE and DOE have been used in small molded parts. However, application to the large molded body is not reported. In this paper, optimization of injection molding process is studied for quality control in mass production of automobile bumper. Mold temperature difference is chosen through robust design of injection molding process, the molding process being optimized in term of shrinkage and deflection. The optimal conditions through DOE are validated by using injection molding analysis.

• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.12 no.5
• /
• pp.80-87
• /
• 2003

Air partial pressure ratio and inlet air mass flow are influenced by water vapor and gaseous fuel in mixture on Compressed Natural Gas (CNG) engines. In this paper, the effects of the water vapor and the gaseous fuel that change the air mass flow and the air-fuel ratio are studied. Effective air mass ratio is defined as the air mass flow divided by mixture mass flow, and also it is applied to the estimation of the inlet air mass flow and the air-fuel ratio. The presence of the gaseous fuel and the water vapor in the mixture reduces the air partial pressure and the effective air mass ratio of the CNG engines. The experimental results for the CNG engine show that estimation of the air-fuel ratio based upon the effective air mass ratio is more accurate than that of a normal mode.

• Journal of IKEEE
• /
• v.23 no.4
• /
• pp.1387-1392
• /
• 2019

Aspherical mirrors have lighter weight and better performance than spherical mirrors, but it is difficult to process their shape and measure the processing precision. Especially, large aperture aspherical mirrors mounted on satellites need high processing precision and long processing time. The computerized numerically controlled machine of gantry type has been used in polishing process, but it has difficulties in processing the complex shapes due to the lack of degrees of freedom. In order to overcome this problem we developed a polishing system using an articulated industrial robot. The system consists of tool path generating program, real-time robot monitoring, and control program. We show the performance of the developed system through the computer simulation and actual robot operation.

• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.15 no.6
• /
• pp.88-96
• /
• 2006

The objective of this research works is to develop back panel dies of PDP TV with a large size. In order to design the geometry of the dies and an initial size of blank optimally, the finite element analysis has been carried out using AUTOFORM V4.2. The conner radius of the upper trimming area and the distance from the outer line of the blank holder to the outer line of the blank have been selected as design parameters to remove the wrinkling of the trimming area. The results of the analyses have been shown that a feasible product without wrinkles and skid lines can be obtained when the conner radius ranges from 6mm to 8mm and the distance lines in the range of 40-60mm. From the proposed design of the dies and an initial blank size, the final die set of the back panel has been successfully manufactured.