• Fire Science and Engineering
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• v.11 no.4
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• pp.15-23
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• 1997

A series of measurements and visualization to investigate the extingushiment of water sprays with pool fires is presented. Fire source is a small-scale pool burner with methanol, ethanol and gasoline. Measurements of temperature, O2, CO2, and CO concentrations along the plume centerline are carried out to observe pool structures without water sprays. Visualization by the Ar-ion laser sheet flow pattern of droplets of the sprays above the pool fires. It is observed than in the case of methanol and ethanol, water sprays continuously penetrate into the center of fuel surfaces. The gasoline pool fire allows intermittent penetration of water sprays because of pulsating characteristics of the gasoline flame. To evaluate the cooling effect of the fuel surface by the sprays, the temperature was measured at the fuel surface. As soon as the mists reach the fuel surface of methanol and ethanol, the temperatures of the fuel surface decrease rapidly below the boiling point, and then the fires are extinguished. Due to the application of mist upon the gasoline fire, though the fuel temperature decrease abruptly at the time of the injection, such a repid decrease do not continue till the extinction point.

• Journal of the korean Society of Automotive Engineers
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• v.14 no.3
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• pp.71-79
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• 1992

Recently, air pollution and energy security problems have necessitated the development of alternative fuel vehicles. As an alternative fuel vehicle FFV(Flexible Fuel Vehicle) which can be operated by and mixture between gasoline and M85(methanol 85% and gasoline 15% by vol. percent) has been drawing great attention. But poor cold startability of high methanol- content fuel which is characteristic of lower fuel volatility and higher latent heat of vaporization than gasoline is one of the major problems to be solved for the development of FFV. In this paper, important factors influencing cold startability of general S.I. engines are described. And, so-me cost-effective and practical methods were investigated in view of the optimization of fuel-ing parameters and ignition system for M85 fuel. The test results showed good startability up to (-22)-(-23).deg.C.

• Journal of ILASS-Korea
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• v.15 no.2
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• pp.61-66
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• 2010

Fuel spray characteristics of the gasoline engine injector has been studied experimentally. To provide fundamental performance data of 4-hole and 12-hole injectors, spray fuel-mass distribution, wall wetting fuel amount and visualization of injectors have been tested and measured with various fuel supply pressure conditions. Spray visualization has been performed to analyze spray formation, spray angle, stream width and penetration length. Test result shows that wall wetting is greatly influenced by the induction air amount and spray atomization. Spray visualization shows that the 12-hole injector has robust performance characteristics with various fuel supply pressure conditions compared with the 4-hole injector. 4-hole injector generates relatively less wall-wetting fuel amount than 12-hole injector does.

• Transactions of the Korean Society of Automotive Engineers
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• v.17 no.1
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• pp.87-95
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• 2009

EGR(Exhaust gas recirculation) provides an important contribution in achieving the development targets of low fuel consumption and low exhaust emission levels on gasoline engine for hybrid vehicles while allowing stoichiometric fuelling to be retained for applications using the three-way catalysts. However, the occurrence of excessive cyclic variation with high EGR normally prevents substantial fuel economy improvements from being achieved in practice. Therefore, the optimum EGR rate in gasoline engine for hybrid vehicles should be carefully determined in order to achieve low fuel consumption and low exhaust emission. In this study, 2 liters gasoline engine with E-EGR system was used to investigate the effects of EGR with optimum EGR rate on fuel economy, combustion stability, engine performance and exhaust emissions. As the engine load becomes higher, the optimum EGR rate tends to increase. The increase in engine load and reduction in engine speed make the fuel consumption better. The fuel consumption was improved by maximum 5.5% at low speed, high load operating condition. As the simulated EGR variation on a cylinder is increased, due to the increase in cyclic variation, the fuel consumption and emissions characteristics were deteriorated simultaneously. To achieve combustion stability without a penalty in fuel consumption and emissions, the cylinder-to-cylinder variations must be maintained under 10%.

• Transactions of the Korean Society of Mechanical Engineers
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• v.6 no.2
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• pp.121-132
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• 1982

Engine torque, specific fuel consumption and MBT spark advance of a domestic automotive engine fueled with methanal-gasoline blends or straight methanal were studied under steady state condition and compared to those obtained with gasoline. The effects of adding methanal to gasoline on engine performance were studied with or without any carburetor modification. At first, the engine was operated without any modification. Next, the diameters of metering orifices in carburetor were modified to give the same excess air factor regardless of fuel type under each fixed engine operating condition. Finally, the diameters of metering orifices in carburetor were modified to give the same excess air factor for 15% mixture of methanal in gasoline by volume as for gasoline with standard metering orifices in carburetor. The effects of adding methanal to gasoline on engine torque, specific energy consumption and MBT spark advance can be explained on the basis of change in stoichiometry caused by the addition of methanal to gasoline.

• Transactions of the Korean Society of Automotive Engineers
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• v.1 no.3
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• pp.46-54
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• 1993

In order to develop a fuel-efficient gasoline engine oil, an experimental study was conducted using an engine dynamometer, a passenger car and the SRV machine. Oil samples with different viscosity were prepared by adding several friction modifiers to select the best one and also to investigate the effect of the viscosity grade. From the study, we have developed engine oils which result in good fuel economy. The viscosity grade of 7.5W/30 was best among the oils investigated with respect to fuel economy and a fatty amine type friction modifier had the good fuel-economy property.

• 한국연소학회:학술대회논문집
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• 2014.11a
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• pp.101-102
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• 2014

Rising oil price and environmental problems are causing automotive industry to increase fuel efficiency. Improved fuel efficiency in gasoline engine was made possible by development of DISI gasoline engine. Since fuel is injected inside cylinder directly, in-cylinder temperature can be reduced than multi-port injection engine and this leads to increased compression ratio. However, engine performance is largely dependent on mixture formation process due to in-cylinder fuel injection. Especially for spray guided and air guided DISI gasoline engine, injection direction is important factor to mixture preparation. It is because interaction between intake flow and spray affect fuel-air mixture. Hence, in this study, mixture formation characteristics were analyzed by varying injection direction using KIVA 3V release2 code. Residual gas was considered for assuming combustion. Therefore, initial condition for in-cylinder temperature was set equal to the end state of exhaust stroke of combustion cycle. Since angle between intake air flow direction and spray direction affects fluid flow and evaporation field, mixture distribution was affected by fuel injection direction dominantly.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.4
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• pp.143-150
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• 2008

EGR(exhaust gas recirculation) is an attractive means of improving the fuel economy of spark ignition engines, as it offers the benefits of charge dilution (lower pumping and cooling losses) while allowing stoichiometric fuelling to be retained for applications using the three-way catalysts. However, the occurrence of excessive cyclic variation with high EGR normally prevents substantial fuel economy improvements from being achieved in practice. Therefore, the optimum EGR rate in Gasoline-Hybrid engine should be carefully determined in order to achieve low fuel consumption and low exhaust emission. In this study, 2 liters gasoline engine with E-EGR system was used to investigate the effects of EGR on fuel economy, combustion stability, engine performance and exhaust emissions. EGR tolerance with load variation was found to be more sensitive than with rpm variation. With optimal EGR rates, the fuel consumption was improved by 5.5% while a combustion stability was guaranteed.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 1997.11a
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• pp.518-525
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• 1997

A series of measurements and visualization to investigate the interaction of water sprays with pool fires is presented. Fire source is a small-scale pool burner with methanol, ethanol and gasoline. Measurements of temperatures, $O_2$, $CO_2$, and CO concentrations along the plume centerline are carried out to observe pool fire structures without water sprays. Visualization by the Ar-ion laser sheet shows flow pattern of droplets of the sprays above the pool fires. It is observed that in the case of methanol and ethanol, water sprays continuously penetrate into the center of fuel surfaces. The gasoline pool fire allows intermittent penetration of water sprays because of pulsating characteristics of the gasoline flame. To evaluate the cooling effect of the fuel surface by the sprays, the temperature was measured at the fuel surface. As soon as the mists reach the fuel surface of methanol and ethanol, the temperatures of the fuel surface decrease rapidly below the boiling point, and then the fires are extinguished. Due to the application of mist upon the gasoline fire, though the fuel temperature decrease abruptly at the time of the injection, such a rapid decrease do not continue till the extinction point.

• Korean Chemical Engineering Research
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• v.51 no.2
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• pp.250-256
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• 2013

Gasoline generates organic acid and polymer (gum) by hydrocarbon oxidation depending on the storage environment such as temperature and exposure to sunlight, which can cause metal corrosion, rubber and resin degradation and vehicle malfunction caused by accumulation in fuel supply system. The gasoline which has not been used for a long time in bi-fuel (LPG-Gasoline) vehicle causes problems, and low octane number gasoline have evaporated into the field, but the exact cause has not been studied yet. In this study, we suggest a plan of quality management by investigating the gasoline oxidation behavior. In order to investigate the oxidation behavior of gasoline, changes of gasoline properties were analyzed at various storage conditions such as storage time, storage vessel type (vehicle fuel tank, PE vessel and Fe vessel) and storage circumstances (sunlight exposure and open system, etc.). Currently distributing gasoline and bioethanol blended fuel (blended 10%) were stored for 18 weeks in summer season. The sample stored in PE vessel was out of quality standard (octane number, vapor pressure, etc.) due to the evaporation of the high octane number and low boiling point components through the vessel cap and surface. Especially, the sunlight exposure sample stored in PE vessel showed rapid decrease of vapor pressure and increase of gum. Bioethanol blended fuel showed similar results as gasoline.