• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.13 no.3
• /
• pp.98-103
• /
• 2004

Diesel engine offers superior fuel consumption than gasoline engine of equivalent capacity. For this reason, diesel engines are widely used in heavy duty transport applications. Specially, it has been many years that exhaust gases from gasoline automobile rather than from diesel is the major object concerned by Korea and other countries, and it is strongly required on the reduction techniques on harmful NOx, Soot, CO, He. Thus, this paper focused on the emission reduction and target for this paper is heavy-duty diesel engine equipped with power filter such as wet type air cleaner. In this paper, the performance, exhaust emissions(CO, THC, NOx, Soot) and noise of heavy-duty diesel engine were measured at maximum load condition and the range of 1,000∼2,200rpm. The smoke was measured at FAS(Free Accel Smoke) test mode.

• Journal of Energy Engineering
• /
• v.23 no.3
• /
• pp.88-95
• /
• 2014

In general, odorants are added to fuel gases, such as LPG, LNG and city gas, to prevent gas poisoning, ignition, explosion, or other accident caused by fuel gases, and to enable immediate and easy detection of fuel-gas leakage by emitting an offensive smell. This study describes a study on the performance and exhaust emissions (CO, THC, $CO_2$, $NO_x$, $SO_2$) characteristics of liquefied petroleum gas (LPG) engine using LPG fuel with new sulfur free odorant (K-Petro S-Free). New sulfur free odorant (40 mg/kg) was added to 2 type LPG fuels for summer, and winter and it was used in performance and exhaust emissions, compare to LPG fuel with sulfur containing odorant (EM, ethyl mercaptan). Engine performance using LPG with sulfur free odorant was similar to LPG with sulfur-containing odorant. Exhaust emissions (CO, THC, $CO_2$, $NO_x$) of LPG with sulfur free odorant were also similar characteristics, compare with sulfur containing odorant. Especially, $SO_2$ emission using LPG with K-Petro S-Free odorant was more reduced 83 % than LPG with sulfur containing odorant(EM) at 2000 rpm.

• Transactions of the Korean hydrogen and new energy society
• /
• v.19 no.2
• /
• pp.139-144
• /
• 2008

The focus of this research is that the scavenging aspect of in-cylinder is visualized by the PIV method and its characteristic is analyzed so that the scavenging performance of the free piston hydrogen fueled engine can improve with loop scavenging. As the results, the piston of convex type shows the best scavenging performance among the presented pistons. In case of the abnormal expansion, the scavenging of area between cylinder head and cylinder wall doesn't operate well.

• Transactions of the Korean hydrogen and new energy society
• /
• v.31 no.4
• /
• pp.372-379
• /
• 2020

Ammonia-hydrogen dual-fuel engine is a way to reduce greenhouse gas emission because ammonia and hydrogen are carbon-free fuels. In ammonia-hydrogen dual-fuel engine, hydrogen is supplied to improve the combustion characteristic of ammonia. In this study, an ammonia reformer was developed to supply hydrogen for 10 kW class ammonia-hydrogen dual-fuel engine. Thermodynamic characteristic and catalyst were investigated for ammonia reforming. Heat transfer was important for high ammonia conversion of ammonia reformer. 99% of ammonia conversion was obtained when 10 LPM of ammonia and 610℃ of hot gas were supplied to the ammonia reformer.

• Journal of Korean Society for Atmospheric Environment
• /
• v.16 no.5
• /
• pp.529-537
• /
• 2000

Several Pt-based oxidation catalysts with different loading were prepared with various metal precursor solutions and characterized with H$_2$ chemisorption and TEM for Pt particle size. V was added to Pt-based catalyst for inhibiting SO$_2$oxidation reaction, as result, Pt-V/Ti-Si catalyst prepared by ERMS(Free Reduced Metal in Solution) method showed high enough activity and better inhibition on SO$_2$oxidation than Pt only catalyst. Optimum Pt particle size for diesel oxidation reaction turned out to be the size of around 20 nm. A prototype catalyst was prepared for light=duty diesel passenger car, and teated for the emission reduction performance with Korean regulation test mode(CVS-75 mode) on chassis dynamometer. The catalyst shows the performance reduction of 75~94% for CO, 53~67% for HC and 10~31% for PM. In the case of heavy-duty diesel catalyst, the domestic formal regulation teat mode D-13 was adopted for both Na engine and Turbo engine. The conversions of CO and THC are high enough(86% and 41%) while the reductions of NOx and PM are relatively low(3~11%).

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.16 no.3
• /
• pp.169-180
• /
• 2014

Chemical weathering of forest soils can reduce atmospheric $CO_2$ concentration over geologic time scales, providing many essential elements for life. Although many studies have been conducted on the effects of elevated atmospheric $CO_2$ on forest carbon storage using open top chambers and FACE (Free air $CO_2$ enrichment) facilities since the 1990s, studies on chemical weathering of forest soils under elevated $CO_2$ are relatively rare. Here I review on how elevated atmospheric $CO_2$ can affect the chemical weathering of forest soils and suggest directions on future research. Despite the recent advances in chemical weathering of forest soils under elevated atmospheric $CO_2$, it is still not clear how the large volume of forest soils would react under the condition. Future studies on weathering of forest soils covering large areas from the tropics to the polar regions with carefully monitored pre-treatment data would provide key information on how soils, the Earth's life sustaining engine, change under climate change.

• Journal of Advanced Marine Engineering and Technology
• /
• v.28 no.6
• /
• pp.894-905
• /
• 2004

The closed cycle diesel propulsion system is free from the problem of the intake air, exhaust gas and their control that are associated with the conventional diesel propulsion system. The system is composed of a main engine, an exhaust cooler. a $CO_2$ scrubber and a $O_2$ mixer. In this paper, a hardware using microprocessor is proposed in order to monitor and control the oxygen and ratio of specific heat for underwater diesel propulsion system. Also simulation is carried out to ascertain the performance of proposed system.

• Journal of the Korean Society for Precision Engineering
• /
• v.29 no.2
• /
• pp.129-138
• /
• 2012

In this study, three types of large scale multi-tasking machine tools together with core technologies involved have been developed and introduced; a multi-tasking machine tool for large scale marine engine crankshafts, a multi-tasking vertical lathe for windmill parts, and a large scale 5-axis machine tool of gantry type. Several special purpose devices has been necessarily developed for the purpose of handling and machining big and heavy workpieces accurately, such as PTD (Pin Turning Device) with revolving ring spindle for machining eccentric crankshaft pins, hydrostatic rotary table and steady rest for supporting and resting heavy workpieces, and 2-axis automatic swiveling head for high-quality free surface machining. Core technologies have been also developed and adopted on their detail design stage; 1) structural design optimization with FEM structural analysis, 2) theoretical hydrostatic analysis for the PTD and rotary table bearings, 3) box-in-box type cross-rail and octagonal ram design to secure machine rigidity and accuracy, 4) constant spindle rpm control against gravitational torque due to unbalanced workpiece.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.19 no.5
• /
• pp.134-142
• /
• 2011

Although combustion is essential in most energy generation processes, it is one of the major causes of air pollution. Exhaust pipes with circular fin were designed to study the effect of cooling the recirculated exhaust gases (EGR) of Diesel engines on the chemical composition of the exhaust gases and the reduction in the percentages of pollutant emissions. The gases examined in this study were oxides of nitrogen (NOx), carbon dioxide ($CO_2$) and carbon monoxide (CO). In addition, $O_2$ concentration in the exhaust was measured. The designs adopted in this study were about exhaust pipes with solid and hollow fins around them direct surface force measurement in water using a nano size colloidal probe technique. The direct force measurement between colloidal surfaces has been an essential topic in both theories and applications of surface chemistry. As particle size is decreased from micron size down to true Carbon nano Colloid size (<10 nm), surface forces are increasingly important. Nano particles at close proximity or high solids loading are expected to show a different behavior than what can be estimated from continuum and mean field theories. The current tools for directly measuring interaction forces such as a surface force apparatus or atomic force microscopy (AFM) are limited to particles much larger than nano size. This paper use Water and CNC fluid at normal cooling system of EGR. Experimental result showed all good agreement at Re=$2.54{\times}10^4$ by free convection and Re=$3.36{\times}10^4$ by forced air furnace.

• Journal of Advanced Marine Engineering and Technology
• /
• v.40 no.9
• /
• pp.743-748
• /
• 2016

Ship's diesel engines have intrinsic problem to make vibrations caused by cylinder explosion and unbalanced rotating mass. These vibrations might induce noises, are transferred to hull and neighboring structures and cause secondary vibrations. This paper suggests the use of an additional dynamic absorber with a sub-vibration system to reduce the aforementioned vibrations. This dynamic absorber is designed based on an analysis of the free vibration of the engine shafting system and the forced vibrations.