• 한국자동차공학회논문집
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• 제11권5호
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• pp.83-88
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• 2003

Measurements on the combustion characteristics of dimethyl ether(DME:$CH_3$O$CH_3$) as compared with LPC in constant volume combustion chamber have been conducted. The DME is a good alternative fuel having oxygen component in fuel. To elucidate the combustion characteristics of dimethyl ether as a fuel, the combustion pressures, combustion durations, and pollutants(NOx, $CO_2$, CO) are measured with equivalence ratios(Ø), and initial Pressures of fuel-air mixture. In the case of DME, the NOx concentration peaks in leu flame Ø = 0.85~0.9, and $CO_2$ concentration peaks at Ø=1.1, while the CO concentration abruptly rises at the condition of fuel-rich mixtures.

• Tribology and Lubricants
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• 제27권2호
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• pp.109-114
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• 2011

The low temperature characteristics of automotive diesel have been legally regulated due to the fact that solid particle in diesel at low temperature can cause severe problems in the vehicle. The biodiesel is well known for eco-friendly fuel, which is one of the most popular alternative petrodiesel, but it is easy to solidified at low temperature than petrodiesel at low temperature. For that reason, in this study, we investigated the low temperature fuel characteristics of diesel-biodiesel blends which were prepared to mix 6 different kinds of biodiesel to winter diesel fuel, respectively. Also, we confirmed to improve low temperature fuel characteristics by pour point depressant.

• 대한기계학회논문집B
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• 제30권4호
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• pp.358-363
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• 2006

In this study, the effects of oxygenated fuel such as ethylene glycol mono-normal butyl ether(EGBE) was investigated both DI and IDI diesel engine. Because EGBE includes oxygen content approximately 27.1 %, it is a kind of oxygenated fuel that the smoke emission of EGBE blending fuel is reduced remarkably compared with commercial diesel fuel. The focus of this study was to investigate the effects of the addition of oxygenated fuel to diesel fuel on the engine-out emissions and the performance. Smoke emissions of all EGBE blends were reduced substantially in comparison with conventional diesel fuel. This study showed that remarkable reduction of smoke with oxygenate blending fuels in diesel engines including DI and IDI combustion method. Besides, this study showed that simultaneous reduction of smoke and NOx emissions could be achieved by oxygenated fuel and EGR method that was applied to decrease NOx emissions increasing with smoke emissions reduction.

• 동력기계공학회지
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• 제21권4호
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• pp.34-41
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• 2017

Diesel engines with compression-ignition type have superior thermal efficiency, durability and reliability compared to gasoline engine. To control emitted gas from the engines, it can be applied to alternative fuel without any modification to the engine. Therefore, in this study, as a basic study for applying emulsified fuel to the actual diesel engine, analysis of spray behavior characteristics of emulsified fuel was carried out simultaneously by experimental and numerical method. The emulsified fuel consist of diesel, hydrogen peroxide, and surfactant. The surfactant for manufacturing emulsified fuel is comprised of span 80 and tween 80 mixed as 9:1 and fixed with 3% of the total volume of the emulsified fuel. In addition, six kinds of emulsified fuel(EF0, EF2, EF12, EF22, EF32, and EF42) were manufactured according to the mixing ratio of hydrogen peroxide. The droplet and spray experiments were performed to observe the behavior characteristics of the emulsified fuel. The numerical analysis was carried out using ANSYS CFX to confirm the microscopic behavior characteristics. Consequently, rapid mixture formation can be expected due to evaporation of hydrogen peroxide in emulsified fuel, and it is confirmed that Reitz&Diwakar breakup model is most suitable as breakup model to be applied to the numerical analysis.

• International Journal of Automotive Technology
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• 제8권4호
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• pp.421-428
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• 2007

This paper investigates the combustion and emission characteristics of a compression ignition engine fueled with neat and blended Shell's gas-to-liquid (GTL) fuel, which was derived from natural gas through the Fischer-Tropsch process. The experiments were conducted in a 6-cylinder DI diesel engine with pump timing settings of $6^{\circ},\;9^{\circ}\;and\;12^{\circ}$crank angle before TDC over ECE R49 and US 13-mode cycles separately and compared to a conventional diesel fuel. The results show that GTL exhibited almost the same power and torque output, improved fuel economy and effective thermal efficiency. It was found that GTL displayed lower peak in-cylinder combustion pressure and maximum heat release rate (HRR), the timings of the peak pressure and the maximum HRR were generally delayed, and the combustion durations were almost equivalent for diesel and GTL under the same speed-load condition. The results also indicate that, compared to diesel fuel, GTL blends showed a trend forward decreasing four regulated emissions simultaneously and a higher GTL fraction in blends contributing to further reductions in the emissions. In particular and on average, neat GTL significantly reduced HC, CO, NOx and PM by 16.4%, 17.8%, 18.3% and 32.4%, respectively, for all cases.

• 한국자동차공학회논문집
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• 제18권6호
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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.

• Korean Chemical Engineering Research
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• 제47권2호
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• pp.237-242
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• 2009

화석연료의 고갈과 원유가격 폭등으로 인해 이를 대체할 수 있는 다양한 연료의 개발이 이루어지고 있다. 동물성 지방이나 식물성 기름의 주성분인 트리글리세라이드를 메탄올과 반응시켜 생산된 바이오디젤은 기존의 석유디젤을 대체할 수 있는 친환경적인 연료로 알려져 있다. 본 연구에서는 국내에서 유통중인 경유에 6종류의 원료별 바이오디젤을 일정 비율로 혼합한 뒤, 다양한 연료특성을 분석하였다. 바이오디젤의 농도가 높아질수록 밀도, 동점도, 인화점이 상승하였고, 저온특성은 악화되는 것을 확인하였다. 또한 경유의 중요한 연료특성인 세탄가를 IQT를 이용해 측정한 결과, 바이오디젤의 혼합비율이 높아질수록, 유도세탄가가 높게 측정되었으며, 특히 팜유로부터 생산된 바이오디젤의 경우, 71.26의 높은 유도세탄가가 측정되었다.

• Journal of Electrochemical Science and Technology
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• 제11권4호
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• pp.336-345
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• 2020

Nickel-doped lanthanum cobalt oxide (LaCo_1-xNi_xO_3-δ, LCN) was investigated as an alternative anode material for solid oxide fuel cells. To improve its catalytic activity for steam methane reforming (SMR) reaction, Ni²⁺ was substituted into Co³⁺ lattice in LaCoO₃. LCN anode, synthesized using the Pechini method, reacts with yttria-stabilized zirconia (YSZ) electrolyte at high temperatures to form an electrochemically inactive phase such as La₂Zr₂O₇. To minimize the interlayer by-products, the LCN was coated via a double-tape casting method on the Ni/YSZ anode as a catalytic functional layer. By increasing the Ni doping amount, oxygen vacancies in the LCN increased and the cell performance improved. CH₄ fuel decomposed to H₂ and CO via SMR reaction in the LCN functional layer. Hence, the LCN-coated Ni/YSZ anode exhibited better cell performance than the Ni/YSZ anode under H₂ and CH₄ fuels. LCN with 12 mol% of Ni (LCN12)-modified Ni/YSZ anode showed excellent long-term stability under H₂ and CH₄ conditions.

• 한국자동차공학회논문집
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• 제16권5호
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• pp.84-91
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• 2008

Due to increasing need for better emission characteristics and lower fuel consumption rate in automotive engines, alternative fuels are drawing more attentions recently. The GTL (gas to liquid) is the one of most favored candidates. In this study, emission characteristics are compared between diesel and GTL fuel in commercial 2.0 liter diesel engine and vehicle with CRDi(Common Rail Direct injection) system. The effects of injection timings on emission and fuel consumption rate are compared at various engine speeds and loads. Noticeable reduction in HC, CO and PM emissions are observed due to higher cetane number and low sulfur and aromatic contents in GTL. On the trade-off curve of NOx and PM(Particulate matter) GTL showed much more benefits than diesel, where about 30% of PM mass decreased at the same operating conditions. On CVS 75 mode test in vehicle, GTL showed an excellent emission enhancement, in which 50% of HC, 21% of PM, and 12% of NOx engine-out emissions are decreased compared to ULSD(Ultra low sulfur diesel) fuel.

• 한국수소및신에너지학회논문집
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• 제30권6호
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• pp.567-577
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• 2019

Due to the depletion of fossil fuels and environmental pollution, demand for alternative energy is gradually increasing. Among the various methods, a method to convert biomass into alternative fuel has been proposed. The bio-fuel obtained from biomass through pyrolysis process is called pyrolysis oil (PO) or bio-oil. Because PO is difficult to use directly in conventional engines due to its poor fuel properties, various methods have been proposed to upgrade pyrolysis-oil. The simplest approach is to mix it with conventional fossil fuels. However, due to their different polarity of PO and fossil fuel, direct mixing is impossible. To resolve this problem, emulsification of two fuels with a proper surfactant was proposed, but it costs additional time and cost. Alternatively, the use of alcohol fuels as an organic solvent significantly improve the fuel properties such as fuel stability, calorific value and viscosity. In this study, blends of diesel, n-butanol, and coffee ground pyrolysis oil (CGPO) which is one of the promising PO, was applied to diesel generator. Combustion and emissions characteristics of blended fuels were investigated under the entire load range. Experimental results show that ignition delay is similar to that of diesel at high load. Although, hydrocarbon and carbon monoxide emissions are comparable to diesel, significant reduction of nitrogen oxides and particulate matter emissions were observed.