• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.4
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• pp.130-141
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• 1997

Work on the reduction of particulate matter(PM) from a diesel vehicl has led to a new trp system and a control method to control the combustion rate of the PM filtrated in the trap, which was named as 'Active Exhaust Feeding Regeneration(AEFR) System' by its operation mechanism. Ceramic cordierite filter is a major component of the trap and susceptible to thermal shock. Therefore the system should be designed to reduce the peak temperature and temperature gradients in the trap ; these have been considered to be the main factors causing thermal shock of the filter during the regeneration. It uses the engine's exhaust gas partially for the regeneration of the ceramic filter. It controlled bypass flow rate of the engine's exhaust gas precisely to control the temperature of the gas entrained into the filter. Gas temperatures were measured inside filter, and the oxygen concentration at the outlet of the filter was also monitored during the regeneration to analyze the combustion process of the PM. The temperature distributions and temperature gradients in the filter during the regeneration varied widely according to the regeneration control schemes. Finally, this system shows relatively low peak temperature and temperature gradients in the filter during its regeneration. It is considered that this system uses a mew method to control the combustion rate of the PM, which is different from the methods used in the previous studies.

• Aerospace Engineering and Technology
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• v.5 no.2
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• pp.126-133
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• 2006

This paper deals with technological and design skills for all pneumatical, hydraulical, mechanical and electrical parts related to control valve. Especially, a variety of dynamic characteristics, which are not easily extracted from field tests using control valves, are studied by system-simulation code, AMESim. The simulated results are also compared and examined with actual testing results in terms of physical dynamic characteristics. In addition, this paper contains the simulated system characteristics including dynamic characteristics in component level of valve itself. Based on the results, it is applied to control system of propellant feeding system in liquid-propellant engine of satellite launcher.

• Journal of Biosystems Engineering
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• v.30 no.2 s.109
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• pp.81-88
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• 2005

Manual transplanting Chinese cabbage needs 184 hours per ha in Korea. Mechanization of Chinese cabbage transplanting operation has been highly required because it needs highly intensive labor during peak season. This study was conducted to developed walking-type Chinese cabbage transplanter. In order to find out design factor of the transplanter, a kinematic analysis software, RecurDyn, was used. The prototype was tested in the circular soil bin and its operating motion was captured and analyzed using high speed camera system. Prototype was one row type which utilized original parts of engine, transmission and etc. from walking-type rice transplanter in order to save the manufacturing cost. Success ratio of pick-up device of hole-pin type and latch type were $96.0\%$ and $99.2\%$, respectively. which was highly affected by feeding accuracy of feeding device of seedling. Transplanting device of the prototype produced a elliptic loci which were coincident with those produced by the computer simulation. Prototype proved good performance in transplanting with mulching and without mulching operation, either. Working performance of prototype was 22 hours per ha and operation cost of the prototype was 961,757 won per ha. So, it would reduce $88\%$ of the labor and $29\%$ of operation cost.

• Applied Chemistry for Engineering
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• v.20 no.4
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• pp.391-395
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• 2009

For the conversion of domestic waste-wood into energy, a fixed bed gasifier ($0.9 m{\times}2.4 m$) having the capacity of 2 ton/day was designed and constructed. The dual knife valve was used to feed waste-wood of which size was 3~5 cm and a rotary stoker system was installed in the bottom of gasifier. The pilot gasification system consisted of feeding system, fixed bed gasifier, gravity fine particle collector, heat exchanger for syngas cooling, ID fan, and cooling tower. The operation temperatures of gasifier were $700{\sim}1000^{\circ}C$ and the concentrations of syngas were CO: 25~40 vol%, $H_2$: 7~12 vol%, $CH_4$: 2~4 vol%, $CO_2$: 12~24 vol%. The calorific value of syngas was $1100{\sim}1500kcal/Nm^3$ and was enough to be applied in the industrial combustor. Also the gas engine was operated by using syngas from biomass gasifier and produced 1~4 kW of power.