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Technical Paper

Experimental Investigation in Combustion Characteristics of Ethanol-gasoline Blends for Stratified Charge Engine

The increasing of global energy demand and stringent pollution regulations have promoted research on alternative fuels. In Thailand, ethanol, can be produced from many sources of national agriculture products as renewable fuel, which was strongly promoted by government due to its many merits for use in transportation field. In this study, combustion characteristics of ethanol-gasoline blend (20%, 85%, and 100%) as well as pure gasoline (E0) were investigated by using a swirl-generated constant volume combustion chamber. Flame propagations of different fuel blends were observed by high speed Schlieren photography technique while pressure history data were recorded for detailed combustion analysis. Combustion behavior, combustion duration and rate of pressure rise of all tested fuels were investigated in various swirl intensities and equivalence ratios. In addition, effect of swirl intensities and ethanol concentration on lean misfire limit were also discussed.
Technical Paper

Fast Burning and Reduced Soot Formation via Ultra-High Pressure Diesel Fuel Injection

The relation between the characteristics of a non-evaporating spray and those of a corresponding frame achieved in a rapid compression machine was investigated experimentally. The fuel injection pressure was changed in a range of 55 to 260 MPa and the other injection parameters such as orifice diameter and injection duration were changed systematically. The characteristics of the non-evaporating spray such as the Sauter mean diameter and the mean excess air ratio of the spray were measured by an image analysis technique. The time required for a pressure rise due to combustion was taken as an index to characterize the flame. It was concluded that the mean excess air ratio of a spray is the major factor which controls the burning rate and that the high injection pressure is effective in shortening the combustion duration and reducing soot formation.
Technical Paper

Investigation of Effects of Ignition Improvers on Ignition Delay Time of Ethanol Combustion with Rapid Compression and Expansion Machine

This work investigates the effects of ignition improvers on the ignition and combustion characteristics of hydrous ethanol with 5% by weight water and 1% by weight Lauric acid (Eh95) under simulated diesel engine conditions using the rapid compression and expansion machine (RCEM). Results indicate that hydrous ethanol with commercial additive (ED95) and hydrous ethanol with 5% by weight glycerol ethoxylate in hydrous ethanol exhibit a near identical rate-of-pressure-rise and heat release rate. Ignition delay of hydrous ethanol with 5% by weight glycerol ethoxylate is shorter, but hydrous ethanol with 1% by weight glycerol ethoxylate has longer ignition delay time and different combustion characteristics compared with hydrous ethanol with commercial additive (ED95). Hydrous ethanol with 1% by weight glycerol ethoxylate and hydrous ethanol with 5% by weight glycerol ethoxylate are considered suitable fuels for high compression-ratio diesel engines.
Technical Paper

Low Temperature Starting Techniques for Ethanol Engine without Secondary Fuel Tank

The present study aims to investigate the parameters affecting cold start characteristics of ethanol at low temperature, and suggest a solution to avoid cold starting problem without the installation of second fuel tank. The testing engine is a 125cc volume displacement, single-cylinder four strokes SI engine with fuel injection and ignition timing system controlled by ECU (electronic control unit). The cold starting performance tests were extensively conducted with different percentages of ethanol blends, surrounding temperatures, heating inside combustion chamber, heater injector, pre-cranking without fuel injection, and amount of fuel injection. From the experimental results, when using ethanol fuel in conventional engine, the problem of cold starting was observed at surrounding temperature lower than 20°C for ethanol. Increasing of injection duration can lower the possible cold start temperature of neat ethanol.
Technical Paper

Multi-Step Water Splitting with Mn-Ferrite/Sodium Carbonate System

Multi-step water splitting with Mn-ferrite(MnFe2O4)/sodium carbonate(Na2CO3) system accompanying endothermic reaction was investigated for converting solar energy into chemical energy. This water splitting is caused by the oxidation-reduction of manganese ion in the Mn-ferrite. Multi-water splitting with MnFe2O4/Na2CO3 system was consisted of three steps. The first step was hydrogen generation at 1073K. The second step was oxygen release at 1273K. The third step was Na2CO3 reproduction at 873K. The mechanism of multi-water splitting has been considered by XRD, chemical analysis of colorimetry and back titration. The temperature range 873 to 1273K is quite lower than those studied on the solar furnace reaction (O2 releasing step) in two-step water splitting (1500-2300K). This lower temperature range would permit further progress in converting the direct solar energy into chemical energy.