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Lee, Kwi Young
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A study of the aging of photocatalysts

Institute for Advanced Engineering-Geon Seog Son, Seong Hyuk Ko, Kwi Young Lee
  • Technical Paper
  • 2000-05-0323
Published 2000-06-12 by Society of Automotive Engineers of Korea in South Korea
To reduce cold-start emissions that is a bottleneck of tightened regulation, a photocatalyst was suggested and studied. Conventional TWC can reduce more than 96% of harmful emissions after the activation, but under a cold-start condition it needs a lot of energy to activate. During the activation time (light-off time) harmful gases are exhausted without any purification and it makes the conventional TWC difficult to satisfy tightened regulation. A photocatalyst can be activated by light that has wavelengths lower than 380 nano-meters. The activation needs no time and loss of energy like a TWC.To apply the photocatalyst on a vehicle aftertreatment a photocatalyst system was suggested that uses non-thermal plasma as a light source of photocatalyst. The durability of a photocatalyst was also studied with hydrothermal aging method. The properties of aged catalyst were tested with surface area, phase transformation and conversion efficiency of HC.
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Hydrocarbon adsorber systems for the LEV program

Daewoo Motors Ltd.-Eu Rak Choi
Institute for Advanced Engineering-Geon Seog Son, Sung Hyuk Ko, Dae Jung Kim, Kwi Young Lee
  • Technical Paper
  • 1999-08-0366
Published 1999-07-13 by Society of Automotive Engineers of Japan in Japan
Hydrocarbon adsorber is considered as a promising technology to reduce cold-start HCs in automotive exhaust gas. In this study, three in-line adsorber systems were tried to reduce the cold-start emission. To check the basic characteristics of the adsorbers, surface area, temperature programmed adsorption/desorption were examined after a hydrothermal aging. Also idle engine bench was used to know the adsorption and desorption capabilities of the adsorber systems at cold start. Finally, a practicability of the adsorber systems for the LEV program was checked with FTP test on a 2.0D M/T vehicle. The results of this study indicate that hydrocarbon adsorber system is one of the promising passive technologies for ULEV regulations.
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A Study on the Practicability of a Secondary Air Injection for Emission Reduction

Daewoo Motor Co.-Eui Rak Choi, Young Woong Kim
Institute for Advanced Engineering-Geon Seog Son, Dae Jung Kim, Kwi Young Lee
Published 1999-05-03 by SAE International in United States
In this study, feasibility tests of secondary air injection technology and lean A/F control technology were performed for LEV program using the FTP75 test on a 2.0 DOHC A/T vehicle. Second-by-second emissions and temperatures were evaluated. The temperatures of exhaust gas were measured at exhaust manifold, front of warm up, and the center of warm up converter. At first, amount of secondary air injection was determined with a bench aged warm up converter and a fresh UCC. And then, the performances of secondary air injection and lean A/F control strategy were compared with 80,000km vehicle aged converters(warm up converter, UCC). Both secondary air injection and lean A/F control technologies satisfied the ULEV regulation. This study shows that the lean A/F control strategy can be one of the potential technologies to meet the LEV/ULEV regulations without an active system that need a cost up.
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Study of a Piston Ring Assembly Design Through Experimental and Numerical Investigation of Inter-Ring Gas Pressure and Blow- By in a Four-Stroke SI Engine

Daewoo Motor Co., Ltd.-Yooseok Chung, Sang Myung Chun
Institute for Advanced Engineering-Jeong Eui Yun, Kwi Young Lee
  • Technical Paper
  • 958524
Published 1995-11-04 by Society of Automotive Engineers of Japan in Japan
Small pressure transducer and signal transmit systems were developed, and applied to measure the inter-ring gas pressure in a four stroke SI engine running at a full load condition. Inter-ring gas pressure was measured to tune in the orifice discharge coefficients for the concurrent simulation study. Measurement of cylinder pressure and blow by were also made simultaneously. Discharge coefficient of top ring was observed significantly lower than that of other rings. Simulations were performed under the starved lubrication condition using a commercially available RINGPAK program adjusted with the experimental result to investigate the influence of piston ring assembly design variable on blow by and friction.
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An Application of Simplified Average Reynolds Equation for Mixed Lubrication Analysis of Piston Ring Assembly in an Internal Combustion Engine

Daewoo Motor Co., Ltd.-Yooseok Chung, Sang Myung Chun
Institute for Advanced Engineering-Jeong Eui Yun, Kwi Young Lee
Published 1995-10-01 by SAE International in United States
A mixed lubrication model based on the average Reynolds equation has been used so far for the tribological analysis of a piston ring assembly. In this study, a simplified average Reynolds equation is applied for mixed lubrication analysis of a ring assembly. The tedious numerical procedure and computing time required for the modeling and analysis was significantly reduced by introducing a contact factor to replace the average gap that includes the asperity contact between two lubricated surfaces. It was observed that this model appropriately reflects mixed lubrication characteristic or piston ring from the qualitative analysis.
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Scavenging Flow Simulation of a Four-Poppet-Valved Two-Stroke Engine

Daewoo Motor Co., Ltd.-Soo Chan Park, Sun Moon, Kwi Young Lee
Pohang Institute of Science and Technology-Kang Y. Huh, Ku Kyong Kim, Chang Ryol Choi
Published 1993-03-01 by SAE International in United States
A modified version of KIVA-II code is applied to scavenging flow simulation of a four-poppet-valved two-stroke engine. The standard k-ε turbulence model is used with no slip on the wall. Grid is generated through direct interface with three dimensional CAD data using a commercial CAE package. Valve motion is taken into account by identifying the cells occupied by the valve structure and putting them as solid obstacle cells. Results show reasonable trends for variation of the velocity field and fresh air mass fraction distribution with crank angle. Parametric study shows that the intake port orientation does not have much effect on the cylinder flow and scavenging efficiency due to strong flow diversion by the valves.
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Flow Analysis of Non-Isothermal Three Dimensional Filling Phase in Injection Molding and Its Application

Daewoo Motor Co.-Dae Eop Kim, Geun Seup Jung, Kwi Young Lee
  • Technical Paper
  • 923899
Published 1992-06-26 by Society of Automotive Engineers of Korea in South Korea
Until recently, plastic component design and molding often involved a process of trial and error. It was difficult to establish a quantitative database in component design, mold design, and prototype production. In recent years, the mold-filling simulation has attracted most attention in the area of CAE in plastics. Such simulation provides valuable information for a mold designer in making correct decisions before cutting the tool. The filling process in the injection-molding of thin parts can be treated as a generalized Hele-Shaw flow for non-Newtonian fluids. the viscosity of molten polymer is both shear dependent and highly temperature-sensitive, and a coupling of the flow with the energy equation is necessary. The application of the mold-filling simulation are described in the present paper, with illustrations of how the filling stage of the injection-molding process are treated theoretically and numerically.

A Study on the Optimum Design of a Stiffening Plate for the Vibration Reduction of an Engine Block

Daewoo Motor Technical Center, KOREA-Seong Ho Yoon, Kwi Young Lee
  • Technical Paper
  • 912507
Published 1991-11-01 by Society of Automotive Engineers of Korea in South Korea
The tests on running engines reveal that the vibration levels of an engine block are higher at the lower portion than the upper portion.The objective of this paper is to reduce the vibration levels of an engine block by the stiffening plates with minimum weight increase. The analytical modal analyses of an engine block and the stiffening plates made of aluminum and steel are performed by the Finite Element Method (FEM). The experimental modal analyses are also conducted and two results are correlated. In these validated modal model, an engine block and the stiffening plates are combined by the spring elements. The Component Mode Synthesis is used to obtain the natural frequencies and modes of the combined blocks. The iterative analyses are performed with varying thickness of the stiffening plates in order to design the optimum one which reduces the vibration levels of an engine block effectively with minimum weight increase.The running engine tests confirm that the designed stiffening plate reduce the overall vibration levels of an engine block.

Time Loss Analysis of an Unconventional Piston Engine

Daewoo Motor Co. Ltd., Korea-Hee Keun Oh, Kwi Young Lee
  • Technical Paper
  • 891300
Published 1989-11-01 by Society of Automotive Engineers of China in China
Piston motion affects the thermal efficiency of an internal combustion engine. The efficiency loss due to piston motion is defined as time loss, and accounts for 6 - 7 % of the total loss in a spark ignition engine. In this paper, an analysis is made of the time loss for a conventional slider-crank engine and a perfectly sinusoidal piston motion engine. The heat release rate is modeled using test data from an 1.6 / OHC engine, and parametric studies are made to identify factors affecting thermal efficiencies of engines with conventional and unconventional piston motions.