Effects of Ethanol Ratio in Soybean Oil Biodiesel on Combustion and Emissions in a Partially Premixed Compression Ignition Engine

【摘要】：Combustion and Emission Characteristics of two levels of ethanol addition(60% and 50%) to biodiesel alternative fuels are compared to biodiesel and gasoline while using a Partially Premixed Compression Ignition(PPCI) combustion strategy in this study.Tests were performed on a water-cooling natural inspiration 4-stroke single cylinder diesel engine.The proportional limit could maintain stable operation was 60% ethanol doping ratio(volumetric ratio,E60 B40).10% less ethanol is better to decrease the latent heat of vaporization impact of ethanol,which made it easier to ignite at the end of the compression stroke.High ethanol doping ratio could reduce soot emissions to nearly zero in the whole operating range,which made it possible to avoid particulate filter or cut down particulate treatment costs even this led to higher HC emissions,as HC emissions could be solved relatively easier with three way catalyst or diesel oxident catalyst compared to soot treatment.50% ethanol doping ratio(E50 B50) could be better to reduce all emissions as much as possible and combustion more efficiently when the engine operated under the load of 0.474 MPa BMEP:soot emissions reduced 36%,NOx emissions doubled,HC emissions increased 31%,and CO emissions quadrupled compared to biodiesel;While its HC emissions reduced 50%,CO emissions reduced 17%,NOx emissions increased 87%,and soot emissions increased 8 times(still very small compared to biodiesel) compared to gasoline;Equivalent brake specific fuel consumption(BSFC_E) of ethanol/biodiesel blended fuels reduced nearly 20% compared to gasoline at the same time.