• Journal of Power System Engineering
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• v.19 no.6
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• pp.26-32
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• 2015

The purpose of this study is to investigate the de-NOx performance characteristics according to the $TiO_2$ crystal structures ratio of $V_2O_5$ SCR catalysts. The anatase(100%) SCR catalyst showed the highest desorption peak of 80ppm at about $250^{\circ}C$, and $NH_3$ was not desorbed at $500^{\circ}C$. It can be confirmed that there was many $NH_3$ desorbed at a high temperature among other various crystal structures, which is because the catalyst was more acidized to increase the intensity of acid sites as the content of subacid sulfate ions($NH_2SO_4$) in the rutile phase increases. The anatase/rutile(7%/93%) SCR had the smallest width of de-NOx performance drop according to thermal aging, and had strong durability against thermal aging.

• Journal of Power System Engineering
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• v.17 no.5
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• pp.13-22
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• 2013

This paper reports the investigation of the physical and chemical characteristics of the prepared 3Pt-2MgO-$3ZrO_2$-$2CeO_2/Al_2O_3$ DOC, based on its hydrothermal aging. As a result of impregnating and reducing the $H_2PtCl_6$ $6H_2O$ precursor on a ${\gamma}-Al_2O_3$ basis, it was well dispersed into small particles with the range 2-3nm. This was because the $Al_2O_3$ acted as a barrier to prevent movement of the catalyst particles. For a hydrothermally aged catalyst for 9h at $700^{\circ}C$, its performance when purifying harmful gases decreased compared to a fresh catalyst, but its specific surface area was at the same level. This was because the performance of the catalyst was reduced by the sintering of the precious metal Pt, rather than by washcoat sintering and pore clogging. For an excessively hydrothermally aged catalyst for 9h at $850^{\circ}C$, Pt grew into an approximately 50nm class, formed a cluster compared to a fresh catalyst. The $CeO_2$ promoters also formed clusters among components of the same type, reducing their specific surface area to $114m^2/g$, which was 14% less than a fresh catalyst.

• Journal of Welding and Joining
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• v.26 no.5
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• pp.60-65
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• 2008

Ferritic stainless steels of the 400 series have been available for automotive exhaust system, heat exchanger, radiater etc. in various industrial because heat resistance, corrosion resistance and strength are excellent. Especially, automotive exhaust system is required good heat resistance because typical temperature of exhaust system exposed during operation of engine is reach up to $800^{\circ}C$. However, research for effect of high temperature in ferritic stainless steels is not enough. In this study, high temperature tensile properties of lap weld of ferritic stainless steels(STS 429) were investigated. In accordance with heat input, lap welds had been produced and were evaluated at high temperature($800^{\circ}C$) to compare high temperature tensile properties. In addition, room temperature tensile tests were carried out for non-aging and aging specimens. As a result of R.T tensile test, non-aging specimens were fractured in base metal except for low heat input specimen and aging specimens were fractured in weld metal. Also high temperature tensile test were carried out by aging specimen. After high temperature tensile test, fracture of aged specimen was occurred in base metal except for low heat input specimen. Fracture surface of low heat input specimen in weld metal was confirmed as brittle fracture with observation using scanning electron microscope(SEM). Significant decrease in ultimate tensile strength (between 82 and 85%) was observed for aged ferritic stainless steels(STS 429) when tested at high temperature.

• Transactions of the Korean Society of Automotive Engineers
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• v.4 no.3
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• pp.122-129
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• 1996

The spark timing is one of major parameters to the engine performance and emissions. The ECU controls the spark timing based on preset values, which are functions of load and speed, in most of today's automotive SI engine. In this system, the preset spark timing can be different from optimum value due to the deviations from mass production, aging effects and so on. In the present study, a control logic is investigated for real time adaptation of spark timing to optimal value. It has been found that crank angle of miximum cylinder pressure is one of the appropriate parameters to estimate the optimum spark timing throught experiment. It has also been observed for spark timing convergence by variation of engineering model factors. The simulation program including engineering model for cycle by cycle variation of combustion is developed for surveying spark timing control logic. It is also shown that simulation results reflect experiment outputs and reasonableness of spark timing control logic for crank angle of maximum cylinder pressure.

• Journal of the Korean Society of Safety
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• v.32 no.6
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• pp.22-28
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• 2017

According to the National Fire Data System (NFDS), more than 5,000 vehicle fires have occurred every year for the last 10 years. Vehicle fires are primarily caused by mechanical (breaking system and engine), electrical (wiring and battery), and chemical (oil and fuel gas leakage) problems. The electrical factor has increased with the installation of driver convenience equipment. For example, today, the black box is widely used to provide video data recording of motor vehicle accidents. The black box consists of a front camera, rear camera, and wires. The black box wires are directly connected to the junction box or fuse box from the start battery that operates to provide normal on power supplying for engine stop. It is extremely dangerous when the wires short circuit due to insulation aging, mechanical and electrical stress, etc. In this study, the black box wiring fire risk have been analyzed and investigated when the steady state and abnormal operations, and under the following conditions: wiring arrangements with a high temperature condition, insulation aging, poor contact, and short circuits. The results showed that black box wiring short circuits had a higher fire risk than the other fire hazard elements. To prevent fire hazards caused by black box wiring, the black boxes must be installed by qualified service personnel. Do not modify the wiring, remove the fuse and secure the wiring using cable ties or insulation tape.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.2
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• pp.363-368
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• 2021

Ship engine rooms have improved automation systems owing to the advancement of technology. However, there are many variables at sea, such as wind, waves, vibration, and equipment aging, which cause loosening, cutting, and leakage, which are not measured by automated systems. There are cases in which only one engineer is available for patrolling. This entails many risk factors in the engine room, where rotating equipment is operating at high temperature and high pressure. When the engineer patrols, he uses his five senses, with particular high dependence on vision. We hereby present a preliminary study to implement an engine-room patrol robot that detects and informs the machine room while a robot patrols the engine room. Images of ship engine-room equipment were classified using a convolutional neural network (CNN). After constructing the image dataset of the ship engine room, the network was trained with a pre-trained CNN model. Classification performance of the trained model showed high reproducibility. Images were visualized with a class activation map. Although it cannot be generalized because the amount of data was limited, it is thought that if the data of each ship were learned through transfer learning, a model suitable for the characteristics of each ship could be constructed with little time and cost expenditure.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.17 no.2
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• pp.93-103
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• 1981

It is well-known that nowadays heat resisting and anti-corrosive materials have been widely used as the components materials of gas turbines, nuclear power plants and engines etc. In the fields of machine production industry. And materials for engine components, like as the exhaust valve of internal combustion engine, have been required to operate under the high temperature range of $700^{\circ}C$-$800^{\circ}C$ and high pressured gas with repeated mechanical load for the high performance of engines. For these components, friction welding for bonding of dissimilar steels can be applied for in order to obtain process shortening, production cost reduction and excellent bonding quality. And age hardening recently has been noticed to the heat resisting materials for further strengthening of high temperature strength, especially high temperature fatigue strength. However, it is difficult to find out any report concerning the effects of age hardening for strengthening high temperature fatigue strength to the Friction welded heat resisting and anti-corrosive materials. In this study the experiment was carried out as the high temperature rotary bending fatigue testing under the condition of $700^{\circ}C$ high temperature to the friction welded domestic heat resisting steels, SUH3-SUS303, which were 10hr., 100hr. aging heat treated at $700^{\circ}C$ after solution treatment 1hr. at $1, 060^{\circ}C$ for the purpose of observing the effects of the high temperature fatigue strength and fatigue fracture behaviors as well as with various mechanical properties of welded joints. The results obtained are summarized as follows: 1) Through mechanical tests and micro-structural examinations, the determined optimum welding conditions, rotating speed 2420 rpm, heating pressure 8kg/mm super(2), upsetting pressure 22kg/mm super(2), the amount of total upset 7mm (heating time 3 sec and upsetting time 2 sec) were satisfied. 2) The solution treated material SUH 3, SUS 303, have the highest inclination gradient on S-N curve due to the high temperature fatigue testing for long time at $700^{\circ}C$. 3) The optimum aging time of friction welded SUH3-SUS 303, has been recognized near the 10hr. at $700^{\circ}C$ after the solution treatment of 1hr. at $1, 060^{\circ}C$. 4) The high temperature fatigue limits of aging treated materials were compared with those of raw material according to the extender of aging time, on 10hr. aging, fatigue limits were increased by SUH 3 75.4%, SUS 303 28.5%, friction welded joints SUH 3-SUS 303 44.2% and 100hr. aging the rates were 64.9%, 30.4% and 36.6% respectively. 5) The fatigue fractures occurred at the side of the base matal SUS303 of the friction welded joints SUH 3-SUS 303 and it is difficult to find out fractures at the friction welding interfaces. 6) The cracking mode of SUS 303, SUH 3-303 is intergranular in any case, but SUH 3 is fractured by transgranular cracking.

• Transactions of the Korean Society of Automotive Engineers
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• v.14 no.1
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• pp.8-16
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• 2006

The research was conducted to characterize of Rh-Pd-Pt TWC with a double-layer washcoat for gasoline vehicle. The physical characteristics on surface of catalyst were inspected by BET, SEM and TEM. The characteristics of catalytic reaction were examined by the TPD/TPR and CO-pulse chemisorption. The catalyst $6Hx(0.35\times11\times3)$ showed superior conversion performance after hydrothermal aging process, which was due to small difference of the surface area between. the fresh and the aged catalyst. The CO-chemisorption and surface area were superior in the 600 cpsi catalyst than other catalysts, this catalyst also shown the higher conversion efficiency of the exhaust emissions. From the TPR test, the conversion performance of the aged catalyst was decreased by the agglomeration and sintering of the PM and metal oxides. From the TPD result, it was found that the NO chemisorption was happed on the bottom-layer washcoat with Pd, and the NO chemisorption was re-happened on the upper-layer washcoat with Pt and Rh in the desorption process.

• Journal of ILASS-Korea
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• v.23 no.3
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• pp.128-135
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• 2018

In this study, the following conclusions could be obtained from the analysis of emissions contribution rates and features for contaminated emissions by 13,456 gasoline vehicles passed in the vehicle load test (ASM-idle) under the inspection year 2013 to 2017. It was confirmed that the contamination of the CO, HC, NOx by the displacement is reduced on over 3L engine. As a result of comparing the exhaust gas in the low speed idle mode and the AS2525 mode, the exhaust gas in the low speed idle mode was measured high. It is estimated that if ISG function is applied, emissions from idle condition will be reduced. NOx emissions were reduced when the engine power was above 200HP. It has been confirmed that the amount of exhaust emissions are significantly reduced for vehicles manufactured after 2004. As a result of analyzing the exhaust gas according to the season, it is judged that there is a correlation between HC and NOx according to the ambient temperature. The concentration of exhaust emission in vehicles with high accumulated distance increases, which is considered to be the result of aging of the vehicle.

• Textile Coloration and Finishing
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• v.30 no.2
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• pp.77-89
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• 2018

In the case of fiber/rubber composites for tire applications, the interfacial adhesion between fiber and rubber significantly affects the physical properties of the finished products. Generally, organic synthetic fibers used for tire cords are treated with resorcinol formaldehyde latex(RFL) primer on the surface of the fiber to improve the adhesion to rubber. Changes of adhesion between rubber and tire cords might weaken as temperature rises due to overheating of car engine and friction with road. In this study, the effects of temperature on the primer treated polyketone cord/rubber composites and the changes in interfacial adhesion were investigated. Polyketone cord/rubber composites were prepared after RFL solution treatment on the surface of polyketone fibers. After that, composites was thermally aged at different temperature conditions(60, 80, 100, $120^{\circ}C$) and times(1, 5, 10, 15days). The adhesion strength of polyketone cord/rubber composite treated with RFL primer was higher than untreated composite by more than 3 times. After heat aging, the adhesion strength of untreated polyketone cord/rubber composites increased while the RFL treated polyketone cord/rubber composites decreased somewhat.