• Journal of Korean Society for Atmospheric Environment
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• v.27 no.4
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• pp.443-453
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• 2011

Real-time Traffic Information Service could play a key role in reducing incomplete combustion time remarkably since it can provide traffic information in real-time basis. Emission characteristics of test engines were studied in terms of travel distance and speed. The present study focused on a north district in Daegu, 12 km. The driving for the emission test was done at 8AM, 3PM, 7PM which represents various traffic conditions. The reduced emissions of Greenhouse Gases (GHG) have been measured for a travel distance running at different loads (conventional shortest route and Real-time Traffic Information) and GHG ($CO_2$, $CH_4$, $N_2O$) are all inventoried and calculated in terms of existing emission factors. The emission of GHG has been shown to reduce linearly with travel distance: $CO_2$ (9.15%), $CH_4$ (18.43%), $N_2O$(18.62%).

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.9
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• pp.1260-1268
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• 2012

Recently, lack of power reserve margin was observed quite often. In this paper, we studied the method to secure power source for a short time, to cut the utility power peak load, and to reduce the users electricity bills. Emergency diesel generator of an office building is to be converted into a dual-fuel engine generator which is responsible for a portion of the peak load. Compared to the conventional diesel fuel generator, the proposed dual-fuel engine is able to reduce the generation power cost by dual-fuel combustion, and it also mitigates the building's utility power peak load by charging the building's peak load. If the dead resources (a group of emergency dual-fuel engine generators), as a Virtual Power Plant, are operating in peak time, we can significantly reduce future large power development costs. We investigated the current general purpose electricity bills as well as the records of the building electric power usage, and calculated diesel engine generator renovation costs, generation fuel costs, driving conditions, and savings in electricity bills. The proposed dual-fuel engine generation method reduces 18.1% of utility power peak load, and turned out to be highly attractive investment alternative which shows more than 27% of IRR, 76 million won of NPV, and 20~53 months of payback periods. The results of this study are expected to be useful to developing the policy & strategy of the energy department.

• International Journal of Automotive Technology
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• v.8 no.5
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• pp.575-581
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• 2007

As current and future automobile emission regulations become more stringent, the research on flow distribution for an exhaust manifold and close-coupled catalyst(CCC) has become an interesting and remarkable subjects. The design of a CCC and exhaust manifold is a formidable task due to the complexity of the flow distribution caused by the pulsating flows from piston motion and engine combustion. Transient flow at the exhaust manifold can be analyzed with various computational fluid dynamics(CFD) tools. However, the results of such simulations must be verified with appropriate experimental data from real engine operating condition. In this study, an experimental approach was performed to investigate the flow distribution of exhaust gases for conventional cast types and stainless steel bending types of a four-cylinder engine. The pressure distribution of each exhaust sub-component was measured using a simulated dynamic flow bench and five-hole pitot probe. Moreover, using the results of the pitot tube measurement at the exit of the CCC, the flow distribution for two types of manifolds(cast type and bending type) was compared in terms of flow uniformity. Based on these experimental techniques, this study can be highly applicable to the design and optimization of exhaust for the better use of catalytic converters to meet the PZEV emission regulation.

• International Journal of Automotive Technology
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• v.8 no.2
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• pp.179-184
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• 2007

In this study, the potential use of oxygenated fuels such as ethylene glycol mono-normal butyl ether (EGBE) was investigated in an attempt to reduce the emission of exhaust smoke from diesel engines. Effects of the combustion method on exhaust emission of DI and IDI diesel engines were also examined. Since EGBE is composed of approximately 27.1% oxygen, this is one of several potential oxygenated fuels that could reduce the smoke content of exhaust gas. EGBE blended fuels have been proven to reduce smoke emission remarkably compared to the conventional commercial fuels. The test was conducted with single and four cylinder, four stroke, DI and IDI diesel engines. The study showed that a simultaneous reduction of smoke and NOx emission could be achieved by the combination of oxygenated blend fuels and the cooled EGR method in both DI and IDI diesel engines. It was also found that a reduction rate of exhaust emission in a DI engine was larger than an IDI diesel engine.

• Proceedings of the KIEE Conference
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• 1994.11a
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• pp.172-174
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• 1994

Due to the environmental considerations and the energy crisis, there has been a revival of electric vehicles since 1960s. Research and development work concerning with electric vehicles (EVs) was becoming more intense in last decade. As compared with conventional internal combustion engine (ICE) cars, EVs have the advantages of clean, quiet, better energy efficiency, less maintenance and improving the load factor of electric power systems. However, EVs usually have a snort running range, bad acceleration performance and high initial cost. The main reason for these shortcomings is the low figure of energy density and the high per energy cost of battery at present technology state. So it is very important to optimize the overall drive system design with respect to the maximum utilization of battery, energy, motor torque and inverter power. This paper describes a demonstration model of electric car which is driven by 4-wheel direct method using the vector control.

• Journal of Power System Engineering
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• v.10 no.1
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• pp.19-24
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• 2006

This work treats a controlled auto-ignition (CAI) single cylinder gasoline engine, focusing on the extension of operating conditions. The fuel was injected indirectly into electrically heated inlet air flow. In order to keep a homogeneous air-fuel mixing, the fuel injector was water-cooled by a specially designed coolant passage. The engine performance and emission characteristics were investigated under the wide range of operating conditions such as 40 in the air-fuel ratio, 1000 to 1800 rpm in the engine speed, 150 to $180^{\circ}C$ in the inlet-air temperature, and $60^{\circ}$ BTDC in the injection timing. The ultra lean-burn with self-ignition of gasoline fuel by heating inlet air was achieved in a controlled auto-ignition gasoline engine. It could be also achieved that the emission concentrations of carbon monoxide, hydrocarbons and nitrogen oxide significantly reduced by CAI combustion compared with conventional spark ignition engines.

• Journal of Mechanical Science and Technology
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• v.19 no.6
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• pp.1358-1365
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• 2005

Flue gas recirculation (FGR) is widely adopted to control NO emission in combustion systems. Recirculated flue gas decreases flame temperature and reaction rate, resulting in the decrease in thermal NO production. Recently, it has been demonstrated that the recirculated flue gas in fuel stream, that is, the fuel induced recirculation (FIR), could enhance much improved reduction in NO per unit mass of recirculated gas, as compared to conventional FGR in air. In the present study, the effect of dilution methods in air and fuel sides on NO reduction has been investigated numerically by using $N_2$ and $CO_2$ as diluent gases to simulate flue gases. Counterflow diffusion flames were studied in conjunction with the laminar flamelet model of turbulent flames. Results showed that $CO_2$ dilution was more effective in NO reduction because of large temperature drop due to the larger specific heat of $CO_2$ compared to $N_2$. Fuel dilution was more effective in reducing NO emission than air dilution when the same recirculation ratio of dilution gas was used by the increase in the nozzle exit velocity, thereby the stretch rate, with dilution gas added to fuel side.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.21 no.5
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• pp.650-658
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• 1997

Analysis and control of intake charge motion such as swirl and tumble are very important factors in improving the gasoline engine performance. In this paper, single-frame PTV (particle tracking velocimetry) is used to investigate intake tumble patterns in a steady flow test rig of gasoline engine with dual-intake-valve and pent-roof combustion chamber. Intake tumble pattern is quantified in accordance with blockage ratio of TIV (tumble intensifying valve) with single- frame PTv.The view of the instantaneous 2-D velocity field gives a realistic understanding of in-cylinder flow field. Thus it is confirmed that PTV is a effective tool in engine design. In conventional port, two tumble structures appear clearly, and the larger one is observed under the exhaust valve side and the smaller is right below the intake valve side. The larger vorticity is observed in TIV port, thus it is concluded that TIV have an effect on intensified tumble motion in cylinder flow.

• Transactions of Materials Processing
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• v.32 no.3
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• pp.122-128
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• 2023

As electric vehicles (EV) have increasingly replaced the conventional vehicles with internal combustion engines (ICE), most of automotive makers are actively devoting to the technology development of EV parts. Accordingly, the manufacturing process for power source has been also shifting from engine/transmission to EV motor/reducer system. However, lack of experience in developing the EV motor still remains as a technical challenge. In this paper, we employed the forming simulation based on finite element modeling to solve this problem. In particular, in order to increase the accuracy of the forming simulation, we introduced the elastic-plastic constitutive model parameters for polymer-copper hybrid wire by investigating the individual strain-stress curves, and elastic modulus of polymer and copper. Then, the reliability of modeling procedure was confirmed by comparing the simulated results with experiments. Finally, the identified mechanical properties and finite element modeling were applied to a hairpin forming process, which involves multiple deformation paths such as bending, pressing, widening, and twisting. The proposed numerical approach can replace common experience or experiment based trials by reducing production time and cost in the future.

• Transactions of Materials Processing
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• v.32 no.3
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• pp.129-135
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• 2023

The use of engineering plastic products in internal combustion engine and electric cars to improve stiffness and reduce weight is increasing significantly. Among various lightweight materials, engineering plastics have significant advantages such as cost reduction, improved productivity, and weight reduction. In particular, engineering plastics containing glass fibers are used to enhance stiffness. However, the stiffness of glass fibers can increase or decrease depending on their orientation. Before developing plastic products, optimal designs are determined through injection molding and structural analysis to enhance product reliability. However, reliable analysis of products with variable stiffnesses caused by anisotropy cannot be achieved via the conventional isotropic structural analysis, which does not consider anisotropy. Therefore, based on the previously reported study "the Effect of Impacted Fracture in Glass Fiber Orientation with Injection Molding & Structural Coupled Analysis," this study aims to investigate the structural analysis and degradation mechanisms of various polymers. In particular, this study elucidates the actual mechanism of plastic fracture by analyzing various fracture conditions and their corresponding simulations. Furthermore, the objective of this study is to apply the injection molding and structural coupled analysis mechanism to develop engineering plastic products containing glass fibers. In addition, the study aims to apply and improve the plastic fracture mechanism in actual products by exploring anisotropy and stiffness reduction owing to the unfilled polymer weld line.