Vicinity Of Spark Plug Research Articles

초희박 LPG 직접분사식 엔진에서 질소산화물 저감을 위한 배기재순환 적용성 평가

Abstract - In order to keep the competitiveness of LPG fuel for transportation fuel, the difference in fuel consumption with gasoline and cost for an aftertreatment system should be reduced with continuous development of technology for LPG engine. In the present study, spray-guided type direct injection combustion system, whose configuration is composed of direct injector in the vicinity of spark plug, was employed to realize stable lean combustion. A certain level of nitrogen oxides(NO x ) emits due to a locally rich mixture regions in the stratified mixture. With the application of EGR system for the reduction of NO x , 15% of NO x reduction was achieved whereas fuel consumption and hydrocarbon emission increased. By the application of EGR, the combustion speed reduced especially appeared at initial flame development period and peak heat release rates and increasing rates for heat release rate decreased as EGR rate increased due to the dilution effect of intake air.Key words : LPG engine, Lean combustion, Spray-guided type direct injection system, Exhaust gas recirculationKIGAS Vol. 19, No. 4, pp 22~28, 2015 http://dx.doi.org/10.7842/kigas. 2015.19.4.22(Journal of the Korean Institute of Gas)

Development of instrument for measurement of fuel–air ratio in vicinity of spark plug: application to DI gasoline engine

An instrument to measure time-resolved fuel–air ratio in the vicinity of a spark plug was developed. Properties of absorption and scattering at the wavelengths of visible and infrared rays were utilized to determine the fuel–air ratio in the mixture including liquid and vaporized fuel. The measurement error of the instrument was within 10% as a result of comparison between the overall and the measured fuel–air ratio at the vicinity of the spark plug under the inlet port injection, which forms a relatively homogeneous mixture. The instrument was applied to a direct injection gasoline engine and the mixture formation process was clarified.

Development of Instrument for Measurement of Fuel-Air Ratio in the Vicinity of Spark Plug. Application to DI Gasoline Engines.

An instrument to measure time-resolved fuel-air ratios in the vicinity of a spark plug was developed. Absorption and scattering at the wavelengths of visible and infrared rays were utilized to determine the fuel-air ratios in the mixture including liquid and vaporized fuel. The measurement error of the instrument was estimated within 10% from comparison between the overall and the measured fuel-air ratios at the vicinity of the spark plug with inlet port injection which froms homogeneous mixture. The instrument was applied to direct injection gasoline engines and the mixture formation process was discussed.

In-cylinder measurement of mixture maldistribution in a L-head engine

The distribution of fuel-air mixtures in many L-head engines is not homogeneous. If the local mixture is too rich or too lean, then incomplete combustion occurs. This can play a major role in unburned hydrocarbon and carbon monoxide emissions. Fuel-air mixture distribution depends on in-cylinder swirl and turbulence, and is directly related to intake-manifold configuration, fuel-delivery-system design and combustion-chamber shape. Understanding the spatial mixture distribution may help improve the design of these aforementioned components. Consequently, a more complete combustion process may result, and emissions reduced. An optical fiber bundle was used to measure the emissions of CH and C 2 radicals in this research to map the mixture uniformity in the combustion chamber. The experimental results showed that there exists a relationship between the intensity ratio ( I C2 I CH ) and the fuel equivalence ratio. The local fuel equivalence ratios can be obtained after the relationship between the light intensity ratio and fuel equivalence ratio is established. In addition, fuel-rich combustion zones were identified in the vicinity of spark plug and valves. Two fuels, propane (C 3H 8) and Indolene (CH 1.86) 7, were used for investigating the effects of different types of fuel on the intensity ratio. A L-head spark-ignition engine was selected for this study since this type of engine uses a conventional carburetor in which the fuel-air mixture is relatively nonhomogeneous which produces high hydrocarbon emissions. Furthermore, the flat cylinder head supplies sufficient space for the installation of the optical fiber bundles.