Study On Performances Of Diesel Engine Fueled With Biodiesel-diesel-ethanol Blended Fuels

With the increasing of oil resources shortage and people strengthening of environmentalprotection consciousness, the research and application of alternative fuel have been paidattention widely. Biodiesel is renewable fuel which can replace petrochemical diesel, it ismade by oil crops, wild oil plant, engineering microalgae and other aquatic plant oil andanimal fat, food waste oil as raw oil through transesterification process. In this paper, we havestudied the biological diesel oil, diesel oil and ethanol blended fuels miscible, cylindercombustion conditions and constituents of the products of combustion. We add ethanoltogether with biological diesel oil and diesel hybrid solution by using the small density, lowviscosity, high oxygen content of ethanol which can improve the characteristics of mixed fuelspray characteristics and increase the oxygen content, to make the fuel burn in cylinder morecompletely, so combustion efficiency is improved and the formation of carbon smoke and COis inhibited. In this paper, we select BD20, BD20E5and BD20E10three mixed fuel as thefuel of engine to conduct the comparative tests of combustion and emission characteristics ofthe engine.Research shows that:(1) at the same temperature, with the increase of biodiesel volumefraction in the mixed fuel, ethanol dissolved increases.(2) Compared with the BD20, the combustion pressure curve in cylinder, theinstantaneous heat release rate curve and the cumulative release percentage curve of BD20E5and BD20E10lag overall and with the increase of ethanol content, hysteresis rule is moreobvious. In a small load, the peak heat release rate of BD20E5and BD20E10is lower thanBD20. While in the medium and high load, the peak heat release rate of BD20E5andBD20E10is higher than that of BD20. The addition of ethanol makes combustion initial pointof BD20E5and BD20E10lag and combustion check point in advance, so the combustion andheat emission is more concentrated, and the combustion duration is short.(3) Compared with BD20, BD20E5and BD20E10can effectively reduce the emission ofCO and the smoke, and with the increase of ethanol content, the reduction is more obvious.The HC emissions of BD20E5and BD20E10is significantly higher than BD20. Three kinds of fuel NOx emissions has no obvious changes in comparative law, The NOx emissions ofBD20, BD20E5and BD20E10has little difference.