• Journal of KSNVE
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• v.5 no.1
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• pp.75-83
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• 1995

The fluctuation of the engine torque appears to be the major source of the torsional vibration of the automotive driveline. The reduction of this torsional vibration has become a significant problem, due to an increase in the fluctuation of the torque of recent light weighted and high powered engines, along with the requirements of higher performance. The torsional vibration of the automotive driveline can be reduced by smoothing the fluctuation by adjusting the torsional characteristics of the clutch-disc. This paper presents an experimental and theoretical research on the clutch-disc torsional characteristics for the reduction of the torsional vibration at driving. The effects of clutch-damper on diminishing the torsional vibration were investigated experimentally. A dynamic model for the automotive driveline was developed, and the engine torque of the model were evaluated with experimental data. By executing a simulation using the model, it has become possible to obtain the clutch-disc torsional characteristics and the clutch-disc torsional characteristics for reducing the torsional vibration has been suggested. The results are as follows: (1) By exceuting simulations using nonlinear model of four degrees of freedom, a design technique to determine the clutch-disc torsional characteristics for reducing the torsional vibration at driving was developed. (2) The influence of barious torsional characteristics of the clutch has been studied in examining design parameters, which indicates that the domain to minimize the torsional vibration at driving depends on the characteristics of the clutch-damper, i. e., spring constant and hysteresis.

• Transactions of the Korean Society of Automotive Engineers
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• v.2 no.4
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• pp.91-99
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• 1994

Tunable KrF Excimer Laser is used here for measuring OH and $O_2$ density distribustion in an open $H_2$/air premixed flame and in a combustion bomb. Laser Rayleigh Scattering(LRS) and Planar Laser Induced Predissociative Fluorescence(PLIPF) methods are used to obtain two-dimensional images of total and specific densities. Laser Excitation wavelengths are calibrated via flame images and combustion bomb images show good qualitative a greement with theoretical calculation. Furthermore images in a combustion bomb can be developed to study real Spark-Ignition engine combustions. Our experimental images show that there are no more collisional quenching problem at high pressure environment(including atmospheric pressure) using predissociative fluorescence technique. Further development to obtain two-dimensional temperature dustribution is ready to use eventhough it is not reported in this paper.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.4
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• pp.108-120
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• 1998

A theoretical study of three-dimensional unsteady compressible non-reacting flow inside double flow of monolith catalytic converter system attached to 6-cylinder engine was performed for the achievement of performance improvement, reduction of light-off time, and longer service life by improving the flow distribution of pulsating exhaust gases. The differences between unsteady and steady-state flow were evaluated through the numerical computations. To obtains the boundary conditions to a numerical analysis, one dimensional non-steady gas dynamic calculation was also performed by using the method of characteristics in intake and exhaust system. Studies indicate that unsteady representation is necessary because pulsation of gas velocity may affect gas flow uniformity within the monolith. The simulation results also show that the level of flow maldistribution in the monolith heavily depends on curvature and angles of separation streamline of mixing pipe that homogenizes the exhaust gas from individual cylinders. It is also found that on dual flow converter systems, there is severe interactions of each pulsating exhaust gas flow and the length of mixing pipe and junction geometry influence greatly on the degree of flow distribution.

• Transactions of the Korean Society of Automotive Engineers
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• v.8 no.5
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• pp.105-113
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• 2000

In order to clarify the final process of oil consumption, the distribution and flow of oil through each ring were visualized by induced fluorescence method. Motoring and firing test were performed in a single cylinder research engine with transparent cylinder liner. The appropriate calibration techniques were used to solve the unstability of induced light intensity as well as to know the relation of the oil film thickness and output signal. Oil behavior was also observed at dynamic state by high speed CCD camera. By analyzing the oil film thickness converted from the photographed image, it was observed that the main route of oil transport through each ring is the end gap under the usual operating condition, low engine speed and low load condition. Oil film thickness is observed to be irregular and tend to move in a body horizontally at a given piston land. And it is also found that oil flows through oil ring gap so quickly that it can be observed in a single cycle, but it flows so slowly through top and 2nd compression rings that it takes quite a long time to detect the flow.

• Journal of ILASS-Korea
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• v.17 no.3
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• pp.152-157
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• 2012

This investigation decribes the effect of the combustion and emission characteristics of HCNG engine according to the high purity hydrogen contents. The HCNG fuel was made by the mixture with a high purity hydrogen ($H_2$) and a natural gas. The test vehicle was applied to the bi-fuel (Gasoline and CNG) system and this system was modified from the fuel supply and fuel tank. In addition, the three premixed HCNG fuels with mixed rate of 10, 20 and 30% of hydrogen were used to maintain the safety. In order to analyze the combustion characteristics of HCNG and CNG, the fuel was injected in the combustor with constant volume. The exhaust emission from light duty vehicle with bi-fuel system was analyzed by a chassis dynamometer and emission analyzer. From these results, the reduction rate of NOx emission increased in the HCNG fuel and emission amount of THC and CO shows a similar level with CNG fuel. This study can be utilized the basic data for the development of a new business plans related with HCNG engines.

• Journal of Power Electronics
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• v.16 no.1
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• pp.238-248
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• 2016

The state-of-charge (SOC) and state-of-health (SOH) estimation of batteries play important roles in managing batteries for automotive applications. However, an accurate state estimation of a battery is difficult to achieve because of certain factors, such as measurement noise, highly nonlinear characteristics, strong hysteresis phenomenon, and diffusion effect of batteries. In certain vehicular applications, such as idle stop-start systems (ISSs), significant errors in SOC/SOH estimation may lead to a failure in restarting a combustion engine after the shut-off period of the engine when the vehicle is at rest, such as at a traffic light. In this paper, a dual extended Kalman filter algorithm with a dynamic equivalent circuit model of a lead-acid battery is proposed to deal with this problem. The proposed algorithm adopts a battery model by taking into account the hysteresis phenomenon, diffusion effect, and parameter variations for accurate state estimations of the battery. The validity of the proposed algorithm is verified through experiments by using an absorbed glass mat valve-regulated lead-acid battery and a battery sensor cable for commercial ISS vehicles.

• Transactions of the Korean Society of Automotive Engineers
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• v.24 no.5
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• pp.556-565
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• 2016

As a result of the enforced control of emission, many devices, including the diesel particulate filter, have been installed in diesel cars to reduce the emission of particulate matters. In this study, a car fire case has been investigated and analyzed. A car fire broke out after the vehicle traveled a distance of 1.4 km from a car service center. The car was provided with DPF cleaning when the DPF warning light came on. After being dismantled in the engine room, the car's engine and gearbox were investigated. The findings showed that the rear part of the DPF metal case was melted and punctured, while the honeycomb filter of the DPF was damaged. The car fire was caused by an overheated DPF associated with inaccurate maintenance practice. Therefore, the responsibility of the fire rested on the car service center that performed the DPF cleaning.

• Tribology and Lubricants
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• v.31 no.6
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• pp.245-250
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• 2015

This study investigates the lubrication characteristics of fuel injection pumps with reference to different fuel oils. Medium-speed diesel engines use fuel oils with various viscosities, such as heavy fuel oil (HFO, which is a high-viscosity fuel oil) and light diesel oil (LDO, which is a low-viscosity fuel oil). When fuel oil with a low viscosity is used, both fuel oil and lubricating oil lubricate the system. Thus, the lubrication of the fuel injection pump is in a multi-viscosity condition when the fuel oil in use changes. We suggest three cases of multi-viscosity models, and divide the fuel injection pump into three lubrication sections: a, the new oil section; b, the mixed oil section; and c, the used oil section. This study compares the lubrication characteristics with variation of the multi-viscosity model, clearance. The volume of Section b does not affect the lubrication characteristics. The lubrication characteristics of the fuel injection pump are poor when high-viscosity fuel oil transfers to low-viscosity fuel oil. This occurs because the viscosity in the new oil section (i.e., Section a) dominates the lubrication characteristics of the fuel injection pump. However, the lubricant oil supply in the used oil section (i.e., Section c) can improve the lubrication characteristics in this condition. Moreover, the clearances of the stem and head significantly influence the lubrication characteristics when the fuel oil changes.

• Journal of the Korean Institute of Intelligent Systems
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• v.20 no.3
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• pp.400-405
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• 2010

This paper deals with implementation of intelligent head up display for vehicle safety system. The Implanted new intelligent transport system offer the potential for improved vehicle to driver communication. The most commonly viewed information in a vehicle is from the Head up display, where speed, tachometer, engine RPM, navigation, engine temperature, fuel gauge, turn indicators and warning lights provide the driver with an array of fundamental information. TFT LCD, LCD Back light led, plane mirror, lens and controllers parts were designed to head up display system. Finally, In this paper, we analyze intelligent head up display system for vehicle of driver safety.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.21 no.3
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• pp.123-127
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• 2011

Objectives: The purpose of this study was to investigate the status of asbestos-containing materials (ACMs) used on ships and to consider measures for preventing worker exposure to asbestos fibers. Methods: A total of 17 ships including 16 ships under repair and a ship under construction at shipyards in Korea were investigated. Bulk samples were collected from suspected ACMs on engine exhaust pipes, boiler steam pipes, generator exhaust pipes, and etc. in ships in order to identify the presence of ACMs. Types and contents of asbestos were determined using polarized light microscopy (PLM). Results: ACMs were found from 14 ships out of 17 ships investigated. Only chrysotile asbestos was found from all samples. ACMs were mainly found from samples collected at the exhaust pipes of the engine, generator and incinerator, and boiler steam pipes where exhaust gases or steam of high temperature pass through. In most cases, types of ACMs were asbestos-containing fabrics such as asbestos tape. Friable ACMs were also found in some cases. Use of ACMs on ships was relevant to built time and owner of the ships rather than type and tonnage of the ships. Conclusions: ACMs were found from most ships built prior to 2000s. Therefore, measures for preventing asbestos-related diseases such as preparation of asbestos map on the ship and installation of warning signs, hazard communication with workers (ship-repairing workers, engine room workers and etc.), and follow-up for worker's health management are needed.