• Transactions of the Korean Society of Mechanical Engineers B
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• v.33 no.5
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• pp.334-342
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• 2009

Trends in the automotive market require the application of new engine technologies, which allows for the use of different types of fuel. Since ethanol is a renewable source of energy and has lower $CO_2$ emissions than gasoline, ethanol produced from biomass is expected to be used more frequently as an alternative fuel. It is recognized that for spark ignition (SI) engines, ethanol has the advantages of high octane number and high combustion speed. Due to the disadvantages of ethanol, it may cause extra wear and corrosion of electric fuel pumps. On-board hydrogen production out of ethanol is an alternative plan. This paper investigates the influence of ethanol fuel on SI engine performance, thermal efficiency and emissions. The combustion characteristics with hydrogen-enriched gaseous fuel from ethanol are also examined. As a result, thermal efficiency increase compared to gasoline. Also, reductions in $CO_2$, NOx, and THC combustion products for ethanol vs. gasoline are described.

• Journal of Industrial Technology
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• v.26 no.B
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• pp.21-28
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• 2006

A diesel truck of 1 ton is re-powered by a gasoline engine and the fuelling system of gasoline engine modified to gasoline/CNG bi fuel system. The engine characteristics such as fuel economy and power are evaluated by driving rest, sloping test and dynamometer. The driving test prove the driving cost is saved by 55% and the maximum speed is raised by 13%, which is mainly due to the higher calorific value of CNG. The sloping test is done on the road of which slope is 15%. The truck shows the mean velocity of 88km/h, which means that a re-powered truck is working fine. The BHP are measured by dynamometer. The power and torque produced by a re-powered truck are reduced by 13% and 14% respectively from the power of gasoline engine. The BHP reduction is one of main problems which one has to solve in near future.

• Journal of ILASS-Korea
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• v.22 no.1
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• pp.1-7
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• 2017

Recently, Performance and fuel efficiency of gasoline engines have been improved by adopting direct injection (DI) system instead of port fuel injection (PFI) system. However, injecting gasoline fuel directly into the cylinder significantly reduces the time available for mixing and evaporation. Consequently, particulate matters(PM) emissions increase. Moreover, as the emission regulations are getting more stringent, not only the mass but also the total number of PM should be reduced to satisfy the Euro VI regulations. Increasing the fuel injection pressure is one of the methods to meet this challenge. In this study, the effects of increased fuel injection pressures on combustion and emission characteristics were experimentally examined at several part load conditions in a 1.6 liter commercial gasoline direct injection engine. The main combustion durations decreased about $2{\sim}3^{\circ}$ in crank angle base by increasing the fuel injection pressure due to enhanced air-fuel mixing characteristics. The exhaust emissions and number concentration distributions of PM with particle sizes were also compared. Due to enhanced combustion characteristics, THC emissions decreased, whereas NOx emissions increased. Also, the number concentrations of PM, larger than 10 nm, also significantly decreased.

• Journal of Energy Engineering
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• v.5 no.1
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• pp.42-49
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• 1996

Natural gas is one of the promising alternative fuels for automotive vehicles, because it has lower exhaust emissions and better fuel economy characteristics than those of gasoline, and can be used in conventional gasoline engines without major modifications. In the present study, a conventional gasoline engine was modified to a CNG engine, which can be operated with CNG only, and an engine bench test was performed to calibrate the operating parameters of the engine such as air fuel ratio, spark advance, etc. at various operating conditions. The modified CNG engine, then, was installed on a commercial gasoline vehicle and a vehicle driving test on chassis dynamometer was performed to examine the fuel economy and exhaust emission characteristics. As a result, the prototype CNG vehicle showed lower exhaust emissions and better fuel economy characteristics, but slightly reduced brake horse power, compared to the gasoline vehicle.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.10 no.1
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• pp.58-73
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• 2000

Objectives : This study was performed to evaluate BTEX exposure to gas station service attendants and the critical affect of benzene and MtBE airborne concentration. Methods : the degree of exposure to airborne BTEX and MtBE was examined in the service attendants at seven gas stations across the country during a summer season. The TWAs(time-weighted averages) of atmospheric concentration of substances in personal and area samples, were calculated. The component ratio of BTEX and MtBE in the samples of bulk gasoline from each station studied was also measured. Results : The airborne concentrations of BTEX and MtBE showed a lognormal distribution and The TWA concentrations of benzene in personal samples from each station were 0.089 ppm - 0.18 ppm, and those of toluene were 0.097 ppm - 0.2 ppm. The average TWA concentrations of xylene and ethyl benzene was 0.03 ppm and 0.001 ppm, respectively. The TWA concentrations of MtBE were 0.4 ppm - 1.3 ppm. The volume concentrations of MtBE, toluene, ethyl benzene and xylene in the bulk gasoline samples were 3 - 7.4 %, 3 - 12 %, 0.64 % and 1.5 - 10 %, respectively. Conclusions : The benzene concentration was detected to exceed the ACGIH threshold benzene level of 0.5 ppm, in one of 74 personal and area samples. MtBE, a substitute for aromatic compounds such as benzene in gasoline, was found to bring about a greater chance of exposure to carcinogen, due to its high vapor pressure and carcinogenicity.

• Journal of ILASS-Korea
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• v.9 no.2
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• pp.9-17
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• 2004

The performance characteristics of lean burn system in gasoline engine are mainly affected by the air-fuel mixture in cylinder, gas exchange process of manifold system, exhaust emission of engine, and the electronic engine control system. In order to obtain the effect of performance factors on the optimum conditions of lean burn engine, this study deal with the behavior of mixture formation, gas flow characteristics of air, flow and evaporation analysis of spray droplet in cylinder, vaporization and burning characteristics of lean mixture in the engine, and the control performance of electronic engine control system. The optimum flow conditions were investigated with the swirl and tumble flows in the combustion chamber with swirl control valve. The performance characteristics and optimum condition of flow field in intake system were analyzed by the investigation of inlet flow of air and combustion stabilization on cylinder.

• Journal of the Korea Organic Resources Recycling Association
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• v.8 no.3
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• pp.124-130
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• 2000

This study was conducted to evaluate effects of gas retention time and filling depth of a compost-based biofilter on removal of vapor phase gasoline and to suggest operational improving method. Gas empty bed retention times(EBRTs) were 4, 10, and 20 minutes, respectively. EBRT of over 10 minutes was required in both cases of TPH(total petroleum hydrocarbons) and BTEK (bezene, toluene, ethylbenzene, and xylene). Filling depths were 25, 50, 75, and 100cm, respectively. To treat gasoline TPH effectively, controlling other operational parameters including EBRT and gas loading rate was more important than increasing filling depth simply. 1m filling depth was sufficient in treating BTEX without controlling other operational parameters greatly.

• Journal of the Korean Professional Engineers Association
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• v.44 no.4
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• pp.39-43
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• 2011

To cope with recent high gas prices and global warming phenomenon, the latest gasoline engine technologies are focusing on direction injection, downsizing by turbo charging, variable compression ratio, controlled auto Ignition to enhance fuel efficiency and satisfy emission regulations. The variable valve train technology will be a basement for these innovative technologies in internal combustion engines and is supposed to play a key role to improve low thermal efficiency and pumping loss in gasoline engine caused by low compression ratio and throttled operation respectively.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.11
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• pp.1563-1571
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• 2003

This paper is the second part of several companion papers which compare the method of Air-fuel ratio(AFR) determination. In the previous paper, Eltinge chart was applied to the arbitrary fuel composition and the charts for gasoline, diesel, methanol, M85, liquefied petroleum gas(LPG), natural gas(NG), propane and butane were illustrated. In Eltinge chart, however, unburned hydrocarbon (UHC) is not used for determination of AFR. For improving accuracy, Eltinge suggested UHC compensation after the AFR reading in the chart. This compensation reduced the difference between real and reading value. In the compensation, however, the correction of oxygen and carbon dioxide is uncertain and there might be a mistake in conversion of UHC reading value. Therefore, the error is overestimated comparing with Spindt one which is most widely used. In addition, there is no comparison of the value with other useful methods. In this paper, the compensation of unburned HC was performed in Eltinge chart and the compensated value was compared with Spindts formula over wide range of AFR. The objects of investigating fuel are gasoline, methanol, NG and LPG. The result shows that Eltinge and Spindt method is flawlessly compatible and the difference between the two methods is under 0.3% in a λrange from 0.9 to 1.7. The method fur debugging instrumentation error is also presented.

• Transactions of the Korean hydrogen and new energy society
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• v.12 no.4
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• pp.267-275
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• 2001

To clear the differences of heat transfer coefficient of in-cylinder gas with fuel properties, the transient heat transfer coefficient of hydrogen gas is investigated by using the hydrogen fueled engine. The measured results were also compared with those of gasoline engine and several empirical equations. Transient heat transfer coefficients were determined by measurements of unsteady heat flux and instantaneous wall temperature in the cylinder head. As the main results, it is shown that transient heat transfer coefficients have remarkable differences according to fuel properties, and it's value for hydrogen engine is twice higher than that of gasoline engine. It means that equation of heat transfer coefficient that the effect of fuel properties is considered sufficiently, is needed to analyze or simulate the gas engine performance.