• Transactions of the Korean Society of Automotive Engineers
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• v.18 no.6
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• pp.105-113
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• 2010

In this study, a feasibility test of liquid petroleum gas (LPG) compression ignition (CI) engine has been carried out to study the effectiveness of cetane enhancing additive: Di-tertiary-butyl peroxide (DTBP). Performance and emissions characteristics of a CI engine fuelled with DTBP blended LPG fuel were examined. Also, the effect of EGR (exhaust gas recirculation) on the combustion and emissions characteristics has been investigated. Results showed that stable engine operation over a wide range of the engine loads was possible. Exhaust emissions measurements showed that hydrocarbon were decreased with the blended fuel at enhancing cetane number. Furthermore, the combustion stability of LPG with a cetane number improver was equivalent to that of commercial Diesel fuel. Increasing the EGR rate leads to deteriorate the IMEP (indicated mean effective pressure) and increase the ignition delay. It was found that the exhaust emissions with the EGR resulted in a very large reduction in nitrogen oxides at the expense of higher THC and CO emissions. Considering the results of engine performance and exhaust emissions, LPG blended fuel of enhancing cetane number could be used as an alternative fuel for diesel in a CI engine.

• Journal of the Korean Ceramic Society
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• v.42 no.12 s.283
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• pp.816-820
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• 2005

The doped-ceria is a strong candidate material for an intermediate temperature SOFC. However, the mechanical strength and the magnitude of electrical conductivity need to be increased at low sintering temperature. In this study, to improve both properties, $1at\% $ of Mg, Ca, Cr, Fe, Co, Ni, Cu, Ga, and Zr were added to the GDC20 ($20at\%$ Gd-doped Ceria) and sintered at $1350^{\circ}C$ that is $250^{\circ}C$ lower than $1600^{\circ}C$. With addition, the relative density of the sintered sample increased. Fe, Co, Ni, Cu, Ga doped-GDC20 showed high relative density over $92\%$. Among them, Ga doped-GDC20 showed the most improved sinterability. The conductivity of doped­GDC20 increased by $\~10$ times at $300\~700^{\circ}C$.

• Environmental Engineering Research
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• v.11 no.3
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• pp.149-155
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• 2006

NOx reduction experiments were conducted by direct injection of urea into a diesel fueled, combustion-driven flow reactor which simulated a single engine cylinder ($966cm^3$). NOx reduction tests were carried out over a wide range of air/fuel ratios (A/F=20-40) using an initial NOx level of 530ppm, and for normalized stoichiometric ratios of reductant to NOx (NSR) of 1.5 to 4.0. The results show that effective NOx reduction with urea occurred over an injection temperature range of 1100 to 1350K. NOx reduction increased with increasing NSR values, and about a 40%-60% reduction of NOx was achieved with NSR=1.5-4.0. Most of the NOx reduction occurred within the cylinder and head section (residence time <40msec), since temperatures in the exhaust pipe were too low for additional NOx reduction. Relatively low NOx reduction is believed to be due to the existence of higher levels of CO and unburned hydrocarbons (UHC)inside the cylinder, and large temperature drops along the reactor. Injection of secondary combustible additives (diesel fuel/$C_2H_6$) into the exhaust pipe promoted further substantial NOx reduction (5%-30%) without shifting the temperature windows. Diesel fuel was found to enhance NOx reduction more than $C_2H_6$, and finally practical implications are further discussed.

• Journal of the Korean Society of Propulsion Engineers
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• v.15 no.5
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• pp.48-53
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• 2011

We investigated thermal stability improvement of exo-tetrahydrodicyclopentadiene (exo-THDCP) with thermal stabilizers (additives). The reaction products were sample during the reactions. The compositions of products were determined by gas chromatography-mass spectrometry (GC-MS) to measure thermal decomposition products of exo-THDCP and to specify mechanism for thermal stabilizers. Hydrogen donors (thermal stabilizers) such as 1,2,3,4-tetrahydroquinoline (THQ), benzyl alcohol (BnOH) increased thermal stability of exo-THDCP. These materials donated hydrogen to radical of exo-THDCP produced after initiation of exo-THDCP. We found that stabilization of exo-THDCP radicals decreased activity of primary products of exo-THDCP and lowered formation of secondary products (above-$C_{11}$ products).

• Korean Chemical Engineering Research
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• v.46 no.4
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• pp.747-751
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• 2008

The effect of additives in the synthesis of biodiesel fuel using supercritical methanol was studied in order to examine the possibility of application of spent vegetable oil as a raw material, which has high contents of water or free fatty acid. The experiments were performed by varying the contents of water, free fatty acid or antioxidants respectively in a batch reactor. The contents of fatty acid methyl ester was analyzed by a gas chromatography. As the water contents increased, the contents of fatty acid methyl ester decreased, however, the decrease was very little compared with the alkaline and acid catalyst. The effect of the contents of free fatty acid, vitamin E, and ${\beta}$-carotene was negligible.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.294-299
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• 2010

Thermal stability of exo-tetrahydrodicyclopentadiene (exo-THDCP) were investigated in a batch-type reactor perfectly coated with quartz. The 1 ml liquid product, which was a sufficiently small amount so as not to affect the reaction pressure, was sampled at 90 min intervals during the reaction and determined by gas chromatography-mass spectrometry (GC-MS) to measure thermal decomposition products of exo-THDCP and specify mechanism for additives (thermal stabilizer). Hydrogen donors (thermal stabilizer) such as 1,2,3,4-tetrahydroquinoline (THQ), benzyl alcohol (BnOH) increased thermal stability of exo-THDCP. These materials donated hydrogen to radical of exo-THDCP produced after initiation of exo-THDCP to decrease activity of primary products of exo-THDCP.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.31 no.2 s.257
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• pp.188-194
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• 2007

New diesel engines equipped with common-rail injection systems and advanced engine management control allow drastic decreases in the production of particulate matters and nitrogen oxides with a significant advantage in terms of the fuel consumption and $CO_2$ emissions. Nevertheless, the contribution of exhaust gas after treatment in the ultra low emission vehicles conception has become unavoidable today. Recently the passive type DPF(Diesel Particulate Filter Trap) system for diesel passenger vehicle has been manufactured into mass production from a French automotive maker since the year of 2000. This passive DPF system fully relies on the catalytic effects from additives blended into the diesel fuel and additives injected into the DPF system. In this study, the effects of PM regeneration in the commercial diesel passenger vehicle with the passive type DPF system were investigated in chassis dynamometer CVS(constant volume sampler)-75 mode. As shown in this experimental results, the DPF regeneration was observed at temperature as low as $350^{\circ}C$. And the engine-controlled the DPF regeneration founded to be one of the most promising regeneration technologies. Moreover, the durability of this DPF system was evaluated with a season weather in terms of the differential pressure and exhaust gas temperature traces from a road test during the total mileage of 80,000km.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.6
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• pp.620-625
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• 2015

In an effort to reduce the onset of global warming, the International Maritime Organization Marine Environment Protection Committee (IMO MEPC) proposed the reduction in ship speeds as a way of lowering the proportion of carbon dioxide ($CO_2$) in the Green House Gas emissions from ships. To minimize fuel costs, shipping companies have already been performing slow steaming for their own fleets. Specifically, the slow steaming approach has been adopted for most ocean-going container lines. In addition, because of the increased marine fuel cost that is required to enable increased capacity, there is an urgent need for more advanced fuel-saving technologies. Therefore, in this present study, we propose a fuel-cost reduction method that can improve the performance of diesel engines. We introduce a predetermined amount (0.025% of the amount of fuel used) of fuel additive (oil-soluble calcium-based organometallic compound). For improved experimental accuracy, as the test subjects, we utilize a large two-stroke diesel engine installed in land plants. The loads of the test engine were classified as low, medium, and high (50, 75, and 100%, respectively). We compare the engine performance parameters (power output, fuel consumption rate, p-max, and exhaust temperature) before and after the addition of fuel additives. Our experimental results, confirmed that we can realize fuel-cost savings of at least 2% by adding the fuel additive in low load conditions (50%). Likewise, the maximum combustion pressure was found to have increased. On the other hand, we observed that there was a reduction in the exhaust temperature.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.7
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• pp.204-210
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• 2016

This paper presents an experimental analysis of the growth and oxidation processes of soot particles generated in an isooctane diffusive laminar flame due to incomplete combustion. The effects of iron-based diagnostics were employed to measure the elastic scattering light from soot particles in a flame at different flame heights, and the differential scattering coefficients were calculated through a calibration process. The growth and oxidation of soot particles in flame was investigated by comparing differential scattering coefficients, and the soot volume fraction was seen to decrease in the soot oxidation process. In the same manner, the differential scattering coefficients were calculated for iron-based fuel-additive seeded flame, and these coefficients were revealed to be smaller than those obtained in the fuel-additive unseeded flame. In addition, transmission through the radial direction of the flame was measured, and transmission in the soot oxidation regime was approximately 5% higher for the seeded flame. The propensity of the data coincided well with the differential scattering coefficients, and it can be concluded that the iron component of the fuel additive plays a crucial role as a catalyst, which eventually enhanced soot particle oxidation.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.4
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• pp.399-404
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• 2015

The cost of fuel in ships has recently increased due to a rapid increase in international oil prices and international restrictions regarding the greenhouse effect generated from the burning of fuel. Therefore, different methods for changing the hull designs for improving energy efficiency, developing coating for reducing friction resistances, developing additives for improving engine thermal efficiency, and low-speed operation for reducing fuel consumption have been considered. The developments of high-speed, large-scale, and energy-saving vessels are deemed essential to adapt to the recent high oil price era. Therefore, it is important to analyze Precisely the qualitative and quantitative changes in the resistance value of the local areas of the hull surface. In this study, the engine performance before and after docking was analyzed to examine friction resistance caused by marine growth on the hull as a basic study for improving the energy efficiency. The result was then presented by comparing it with the previous data for 2.5 years between docks to investigate the performance of the main engine, the change in friction resistances and loads, the fuel consumption and ship speed.