• Journal of ILASS-Korea
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• v.19 no.4
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• pp.155-166
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• 2014

This review will be concentrated on the spray characteristics of bioethanol and its derived fuels such as ethanol-diesel, ethanol-biodiesel in compression ignition (CI) engines. The difficulty in meeting the severe limitations on NOx and PM emissions in CI engines has brought about many methods for the application of ethanol because ethanol diffusion flames in engine produce virtually no soot. The most popular method for the application of ethanol as a fuel in CI engines is the blending of ethanol with diesel. The physical properties of ethanol and its derivatives related to spray characteristics such as viscosity, density and surface tension are discussed. Viscosity and density of e-diesel and e-biodiesel generally are decreased with increase in ethanol content and temperature. More than 22% and 30% of ethanol addition would not satisfied the requirement of viscosity and density in EN 590, respectively. Investigation of neat ethanol sprays in CI engines was conducted by very few researchers. The effect of ambient temperature on liquid phase penetration is a controversial topic due to the opposite result between two studies. More researches are required for the spray characteristics of neat ethanol in CI engines. The ethanol blended fuels in CI engines can be classified into ethanol-diesel blend (e-diesel) and ethanol-biodiesel (e-biodiesel) blend. Even though dodecanol and n-butanol are rarely used, the addition of biodiesel as blend stabilizer is the prevailing method because it has the advantage of increasing the biofuel concentration in diesel fuel. Spray penetration and SMD of e-diesel and e-biodiesel decrease with increase in ethanol concentration, and in ambient pressure. However, spray angle is increased with increase in the ethanol percentage in e-diesel. As the ambient pressure increases, liquid phase penetration was decreased, but spray angle was increased in e-diesel. The increase in ambient temperature showed the slight effect on liquid phase penetration, but spray angle was decreased. A numerical study of micro-explosion concluded that the optimum composition of e-diesel binary mixture for micro-explosion was approximately E50D50, while that of e-biodiesel binary mixture was E30B70 due to the lower volatility of biodiesel. Adding less volatile biodiesel into the ternary mixture of ethanol-biodiesel-diesel can remarkably enhance micro-explosion. Addition of ethanol up to 20% in e-biodiesel showed no effect on spray penetration. However, increase of nozzle orifice diameter results in increase of spray penetration. The more study on liquid phase penetration and SMD in e-diesel and e-biodiesel is required.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.4
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• pp.1-9
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• 2014

The vast stores of biomass available in the worldwide have the potential to displace significant amounts of petroleum fuels. Fast pyrolysis of biomass is one of several paths by which we can convert biomass to higher value products. The wood pyrolysis oil (WPO) has been regarded as an alternative fuel for petroleum fuels to be used in diesel engine. However, the use of WPO in a diesel engine requires modifications due to low energy density, high water contents, high acidity, high viscosity, and low cetane number of the WPO. One possible method by which the shortcomings may be circumvented is to co-fire WPO with other petroleum fuels. WPO has poor miscibility with light petroleum fuel oils; the most suitable candidates fuels for direct fuel mixing are methanol or ethanol. Early mixing with methanol or ethanol has the added benefit of significantly improving the storage and handling properties of the WPO. For separate injection co-firing, a WPO-ethanol blended fuel can be fired through diesel pilot injection in a dual-injection dieel engine. In this study, the performance and emission characteristics of a dual-injection diesel engine fuelled with diesel (pilot injection) and WPO-ethanol blend (main injection) were experimentally investigated. Results showed that although stable engine operation was possible with separate injection co-firing, the fuel conversion efficiency was slightly decreased due to high water contents of WPO compare to diesel combustion.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.5
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• pp.420-427
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• 2017

Recently, the depletion of fossil fuels, global warming and environmental pollution have emerged as a worldwide problem, and studies of new renewable energy sources have been progressed. Among the many renewable energy sources, the use of bio fuel has the potential to displace fossil fuels due to low price, easy to handle, and the abundant sources. Pyrolysis oil (PO) derived from waste wood and sawdust is considered an alternative fuel for use in diesel engines. On the other hand, PO is limited to diesel engines because of its low cetane number, high viscosity, high acidity, and low energy density. Therefore, to improve its poor properties, PO was mixed with alcohol fuels, such as ethanol. Early mixing with ethanol has the benefit of improving the storage and handling properties of the PO. Furthermore, a PO-ethanol blended fuel was injected separately, which can be fired through pilot-injected diesel in a dual-injection diesel engine. The experimental results showed that the substitution of diesel with blended fuel increases the amount of HC and CO, but reduces the NOx and PM significantly.

• Transactions of the Korean Society of Automotive Engineers
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• v.17 no.2
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• pp.82-89
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• 2009

In order to investigate the spray characteristics according to diesel and bioethanol blending with biodiesel fuel, macroscopic spray characteristics were analyzed from the comparison of the effect of the injection pressure, ambient pressure and density on the spray tip penetration and spray cone angle. In addition, spray atomization characteristics were studied with local and overall Sauter mean diameter (SMD) and the contour map of SMD distribution at various injection conditions. It was revealed that the spray tip penetration of biodiesel fuels blended with diesel and ethanol was shorter than that of an undiluted biodiesel fuel at low injection pressure. However, the difference of spray tip penetration among three test fuels reduces at a high injection pressure. Increase of the ambient gas density leads to the decrease of the spray tip penetration of three test fuels. When diesel and ethanol fuels add to an undiluted biodiesel fuel, spray cone angle increases due to the decrease of the fuel density at the same ambient pressure condition. On the other hand, the droplet mean diameter decreases due to the reduction of the kinematic viscosity and surface tension.

• Journal of ILASS-Korea
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• v.21 no.3
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• pp.144-154
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• 2016

This review will be concentrated on the spray characteristics of biobutanol and its blends fuels in internal combustion engines including compression ignition, spark ignition and gas turbine engines. Butanol can be produced by fermentation from sucrose-containing feedstocks, starchy materials and lignocellulosic biomass. Among four isomers of butanol, n-butanol and iso-butanol has been used in CI and SI engines. This is due to higher octane rating and lower water solubility of both butanol compared with other isomers. The researches on the spray characteristics of neat butanol can be classified into the application to CI and SI engines, particularly GDI engine. Two empirical correlations for the prediction of spray angle for butanol as a function of Reynolds number was newly suggested. However, the applicability for the suggested empirical correlation is not yet proved. The butanol blended fuels used for the investigation of spray characteristics includes butanol-biodiesel blend, butanol-gasoline blend, butano-jet A blend and butanol-other fuel blends. Three blends such as butanol/ethanol, butanol/heptane and butanol/heavy fuel oil blends are included in butanol-other fuel blends. Even though combustion and emission characteristics of butanol/diesel fuel blend in CI engines were broadly investigated, study on spray characteristics of butanol/diesel fuel blend could not be found in the literature. In addition, the more study on the spray characteristics of butanol /gasoline blend is required.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.38 no.6
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• pp.501-511
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• 2014

Bio-oil derived from biomass through fast pyrolysis process has the potential to displace a significant amount of petroleum fuels. However, the use of bio-oil in a diesel engine is very limited because of its poor properties, e.g., its low energy density, low cetane number, and high viscosity. Therefore, bio-oil should be emulsified or blended with other fuels that have high centane numbers. Because bio-oil has poor miscibility with petroleum fuels, the most suitable candidate fuels for direct mixing are alcohol fuels. In this study, bio-oil was blended with ethanol, and two types of cetane improvers were added to a blended fuel to improve the self-ignition property. The two types of cetane improvers, PEG 400 and 2-EHN, made it possible for bio-oil blended fuels to combust in a diesel engine with a maximum bio-oil content of 15 wt%. A high-compression-ratio piston is also proposed for the combustion of bio-oil in a diesel engine.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.53 no.1
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• pp.89-97
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• 2017

Butanol has an ability to improve the ignition quality due to its lower latent heat of vaporization; it has an advantage to reduce a volume of a fuel tank because its energy density is higher than that of ethanol. Also, butanol-diesel oil blending quality is good because butanol has an effect to prevent the phase-separation between two fuels. Even if the blended oil contains water, it can reduce the corrosion of the fuel line. Thus, it is possible to use butanol-diesel oil blended fuel in diesel engine without modification, and it may reduce the environment pollution due to NOx and particulate and the consumption of diesel oil. Therefore, some studies are being advanced whether butanol is adequate as an alternative fuel for diesel engines, and the results of the combustion and exhaust gas emission characteristics are being presented. Though the injection and spray characteristics of butanol are more important in diesel combustion, the has not yet dealt with the matter. In this study, the influence in which differences of physical properties between butanol and diesel oil may affect the injection and spray characteristics such as injection rate, penetration, spray cone angle, spray velocity and process of spray development were examined by using CRDI system, injection rate measuring device and spray visualization system. The results exhibited that the injection and macroscopic spray characteristics of two fuels were nearly the same.

• Journal of the korean Society of Automotive Engineers
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• v.11 no.1
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• pp.31-43
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• 1989

The paper shows a solution by giving vegetable oil a chemical treatment, i.e., transesterification of the rapeseed oil without any modification of the diesel engine for reducing carbon deposits, and to evaluate rate of combustion with vegetable oils, their esterified fuel and their blend fuels using a double Wiebe's function approximation in a naturally aspired D.I. diesel engine. Since any oil will be as material for ester, if it is fatty acid, the sardine oil was considered. In the experiment, engine performance, exhaust gas emissions, and combustion characteristics were measured and calculated for a number of fuels: rapeseed oil, palm oil, ester of rapeseed oil, and these fuels blended with ethanol or diesel fuel.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.5
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• pp.116-125
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• 2014

Pyrolysis oil (PO), derived from biomass through fast pyrolysis process have the potential to displace significant amounts of petroleum fuels. The PO derived from wood has been regarded as an alternative fuel to be used in diesel engines. However, the use of PO in a diesel engine is very limited due to its poor properties like low energy density, low cetane number, high acidity and high viscosity of PO. Therefore, one of the easiest way to adopt PO to diesel engine without modifications is blended with other fuels that have high centane number. However, PO that has high amount of polar chemicals is immiscible with non polar hydrocarbons of diesel or biodiesel. Thus, to stabilize a homogeneous phase of diesel/biodiesel-PO blends, a proper surfactant should be used. Nevertheless, PO which was produced from different biomass type have varied characteristics and this complicates the selection of a suitable additive for a specific PO-diesel emulsion. In this regard, a more simple approach such as the use of a co-solvent like ethanol or butanol to induce a more stable phase of the PO-diesel mixture could be a promising alternative. In this study, a diesel engine operated with diesel/biodiesel-PO-butanol blends was experimentally investigated. Performance and gaseous & particle emission characteristics of a diesel engine were examined under the engine loads of IMEP 0.2 ~ 0.8MPa.