• Journal of the korean Society of Automotive Engineers
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• v.15 no.1
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• pp.37-44
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• 1993

Fuel injection system is an important tool in the exhaust emission and performance of a diesel engine. Effects of the fuel injection system in diesel combustion was investigated experimentally by measuring the performance and analyzing the combustion phenomena in a D.I. diesel engine. The selected injection parameters were nozzle opening pressure, nozzle projection length, and nozzle spray angle. From the measured results, it is shown that the fuel injection pipe diameter is an effective means to improve engine performance in a middle and high speed range and the 2 stage spring nozzle holder has the advantage of increasing the engine performance due to the initial injection pressure in a low speed range. It has been also shown that increasing nozzle opening pressure resulted in decrease in smoke, but increase in NO$_{x}$ from the engine.e.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.5
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• pp.659-665
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• 2011

Recently, the plastic resin such as PC, ABS are widely used in IT market. Especially, in most cases the keypads mounted on the mobile phone are the dual-injection-plated type. Environmental regulation is based on the quality of injection-molded products and the minimum process steps are required to avoid the plating defects. Various parameters to produce the injection-molded plastic products make it difficult to obtain the desired stability. However, the past experience and the use of CAE analysis make it possible to predict the problems occurred in injection molding process. Especially, the problems of the weld lines such as runner balancing, bending, deformation and forming defects can be solved systematically and minimized by CAE analysis. Through this study, the non-uniform volumetric shrinkage and the difference in temperature distribution induce the deformation and the high value of stress causes the problems such as crack.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.11 s.242
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• pp.1445-1454
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• 2005

In order to minimize warping deformation which is an essential factor in the failure of injection molding parts, this study proposes an optimization design method fer determining design variables of injection molding parts. First, using a commercial package program for injection molding analysis, namely, Computer Aided Plastics Application(CAPA), we investigate the effects of parameters of injection molding process. Next, an optimum design process is established by interfacing CAPA to PQRSM embedded in EMD10S, a design framework developed by the conte. of innovative Design Optimization Technology(iDOT). PQRSM is a very efficient sequential approximate optimization algorithm. Optimum design results demonstrate the effectiveness of the design method suggested in this study by showing that the results of the optimum design is better than those of the initial design. It is believed that the proposed methodology can be applied to other injection molding design applications.

• Journal of the Society of Naval Architects of Korea
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• v.40 no.3
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• pp.9-15
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• 2003

An experimental study has been carried out as a basic research for development of the friction drag reduction technology for ships by polymer injection. Experimental apparatus and procedures have been devised and prepared to measure the changes of the wall friction with injection of a polymer solution and basic experimental data on the friction drag reduction are obtained for a turbulent fiat-plate boundary layer and fully-developed channel flows. Variations of the friction drag reduction with some important parameters of polymer injection, such as the concentration of polymer solution, its injection flow rate and the measuring position downstream from the injection slot, are also investigated. Important experimental data and results obtained in the present study are presented. The amount of friction drag reduction up to 50% is observed.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.946-949
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• 2005

It is very a time-consuming and error-prone process to obtain the optimal injection condition, which can produce good injection molding products in some operational variation of facilities, from a seed injection condition. This study proposes a new approach to search the optimal injection molding condition using a neural network and a genetic algorithm. To estimate the defect type of unknown injection conditions, this study forces the neural network into learning iteratively from the injection molding conditions collected. Major two parameters of the injection molding condition - injection pressure and velocity are encoded in a binary value to apply to the genetic algorithm. The optimal injection condition is obtained through the selection, cross-over, and mutation process of the genetic algorithm. Finally, this study compares the optimal injection condition searched using the proposed approach. with the other ones obtained by heuristic algorithms and design of experiment technique. The comparison result shows the usability of the approach proposed.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.38 no.3
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• pp.100-107
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• 2015

Recently as the manufacturers want competitiveness in dynamically changing environment, they are trying a lot of efforts to be efficient with their production systems, which may be achieved by diminishing unplanned operation stops. The operation stops and maintenance cost are known to be significantly decreased by adopting proper maintenance strategy. Therefore, the manufacturers were more getting interested in scheduling of exact maintenance scheduling to keep smooth operation and prevent unexpected stops. In this paper, we proposedan integrated maintenance approach in injection molding manufacturing line. It consists of predictive and preventive maintenance approach. The predictive maintenance uses the statistical process control technique with the real-time data and the preventive maintenance is based on the checking period of machine components or equipment. For the predictive maintenance approach, firstly, we identified components or equipment that are required maintenance, and then machine parameters that are related with the identified components or equipment. Second, we performed regression analysis to select the machine parameters that affect the quality of the manufactured products and are significant to the quality of the products. By this analysis, we can exclude the insignificant parameters from monitoring parameters and focus on the significant parameters. Third, we developed the statistical prediction models for the selected machine parameters. Current models include regression, exponential smoothing and so on. We used these models to decide abnormal patternand to schedule maintenance. Finally, for other components or equipment which is not covered by predictive approach, we adoptedpreventive maintenance approach. To show feasibility we developed an integrated maintenance support system in LabView Watchdog Agent and SQL Server environment and validated our proposed methodology with experimental data.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.3
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• pp.51-58
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• 2004

Optimization of engine desist and operation parameters using a genetic algorithm was demonstrated for direct injection diesel engine combustion. A micro genetic algorithm and a modified KIVA-3V code were used for the analysis and optimization of the engine combustion. At each generation of the optimization step the micro genetic algorithm generated five groups of parameter sets, and the five cases of KIVA-3V analysis were to be performed either in series or in parallel. The micro genetic algorithm code was also parallelized by using MPI programming, and a multi-CPU parallel supercomputer was used to speed up the optimization process by four times. An example case for a fixed engine speed was performed with six parameters of intake swirl ratio, compression ratio, fuel injection included angle, injector hole number, SOI, and injection duration. A simultaneous optimization technique for the whole range of engine speeds would be suggested for further studies.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.5
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• pp.35-44
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• 2002

Engine cycle simulation using a two-zone model was performed to investigate the effect of the engine parameters on NO and soot emissions in a DI diesel engine. The present model was validated against measurements in terms of cylinder pressure, BMEP, NO emission data with a 2902cc turbocharger/intercooler DI diesel engine. Calculations were made for a wide range of the engine parameters, such as injection timing, ignition delay, Intake air pressure, inlet air temperature, compression ratio, EGR. This parametric study indicated that NO and soot emissions were effectively decreased by increasing intake air pressure, decreasing inlet air temperature and increasing compression ratio. By retarding injection timing, increasing ignition delay and applying EGR. NO emission was effectively reduced, but the soot emission was increased.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.1
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• pp.12-18
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• 2009

In this paper, for reducing the assembly torque of subminiature plastic barrel and base which are the essential parts of mobile phone camera module, the high-precision system for inspecting the screw shape of core, electrode and injection molding products was developed. For realization of inspection process, the inspection parameters for evaluating the manufacturing quality were selected and the measurement methods of selected parameters were developed. Finally, the inspection system which is possible to be applied to the field were fabricated.

• Advances in aircraft and spacecraft science
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• v.2 no.2
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• pp.183-198
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• 2015

Scramjets are a class of hypersonic airbreathing engine that are associated with realizing the technology required for economical, reliable access-to-space and high-speed atmospheric transport. After-burning augments the thrust produced by the scramjet nozzle and creates a more robust nozzle design. This paper presents a numerical study of three parameters and the effect that they have on thrust augmentation. These parameters include the injection pressure, injection angle and streamwise injection position. It is shown that significant levels of thrust augmentation are produced based upon contributions from increased pressure, mass flow and energy in the nozzle. Further understanding of the phenomenon by which thrust augmentation is being produced is provided in the form of a force contribution breakdown, analysis of the nozzle flowfields and finally the analysis of the surface pressure and shear stress distributions acting upon the nozzle wall.