The use of ethanol is a promising method to reduce the emissions of diesel engines.The present study has been based on the installation of a gasoline electronic injection system in a single-cylinder diesel engine to c...The use of ethanol is a promising method to reduce the emissions of diesel engines.The present study has been based on the installation of a gasoline electronic injection system in a single-cylinder diesel engine to control the amount of ethanol entering the cylinder during the compression(while diesel has been injected into the cylinder by the original pump injection system).The injection time has been controlled by crank angle signal collected by an AVL angle indicator.In the tests ethanol and diesel each accounted for half of the fuel volume,and the total heat energy supply of the fuel was equivalent to that of the diesel under the operating conditions of the original engine.A three-dimensional combustion model of the diesel engine has been implemented by using the CFD software FIRE.Simulations have been carried out assuming uniform and non-uniform injections rate for the different holes and the different results have been compared.According to these results,a non-uniform injection rate can produce early ignition and cause an increase in the maximum in-cylinder pressure and the maximum average incylinder temperature.Moreover,in such conditions NO emissions are larger while soot emission is slightly lower.展开更多
The preparation of ethanol-diesel fuel blends and their emission characteristics were investigated. Results showed the absolute ethanol can dissolve in diesel fuel at an arbitrary ratio and a small quantity of water(0...The preparation of ethanol-diesel fuel blends and their emission characteristics were investigated. Results showed the absolute ethanol can dissolve in diesel fuel at an arbitrary ratio and a small quantity of water(0.2%) addition can lead to the phase separation of blends. An organic additive was synthesized and it can develop the ability of resistance to water and maintain the stability of ethanol-diesel-trace amounts of water system. The emission characteristics of 10%, 20%, and 30% ethanol-diesel fuel blends, with or without additives, were compared with those of diesel fuel in a direct injection(DI) diesel engine. The experimental results indicated that the blend of ethanol with diesel fuel significantly reduced the concentrations of smoke, hydrocarbon(HC), and carbon monoxide(CO) in exhaust gas. Using 20% ethanol-diesel fuel blend with the additive of 2% of the total volume, the optimum mixing ratio was achieved, at which the bench diesel engine testing showed a significant decrease in exhaust gas. Bosch smoke number was reduced by 55%, HC emission by 70%, and CO emission by 45%, at 13 kW/1540 r/min. However, ethanol-diesel fuel blends produced a few ppm acetaldehydes and more ethanol in exhaust gas.展开更多
为研究掺烧不同比例的乙醚对柴油机燃烧及排放特性的影响,以4190Z L C-2型船用中速机为研究对象,利用AVL_FIRE仿真软件构建燃烧室高压循环模型,在全负荷工况下对比实测与仿真缸压和放热率曲线,验证模型的准确性。在全负荷工况下,通过仿...为研究掺烧不同比例的乙醚对柴油机燃烧及排放特性的影响,以4190Z L C-2型船用中速机为研究对象,利用AVL_FIRE仿真软件构建燃烧室高压循环模型,在全负荷工况下对比实测与仿真缸压和放热率曲线,验证模型的准确性。在全负荷工况下,通过仿真模拟实验,在柴油中分别掺混体积分数为0%、5%、10%、15%的4种比例的乙醚,研究其对柴油机燃烧和排放特性的影响。结果表明:与燃烧纯柴油相比,使用柴油-乙醚混合燃料,缸内最大爆发压力和缸内最高温度均有所下降,对应的曲轴转角也稍有延后。增加乙醚的掺混比例,CO和NO的排放量均呈现降低趋势,碳烟排放略有增加。在反应过程中,乙醚加入延长了混合燃料的滞燃期,油气混合更加充分,放热过程稳定,提升柴油机的稳定性。当乙醚掺混体积分数为15%时,NO排放量较原机降低12.7%,CO排放量降低7.8%,碳烟排放量增大10.7%。展开更多
基金the National Natural Science Foundation of China(Nos.51476072 and 51366002)the Science and Technology Foundation of Guizhou Province(No.[2018]1006)+1 种基金Supporting Program for Top Scientific and Technological Talents in Universities of Guizhou Province(No.[2018]062)High-level Talent Research Funding Project of Guizhou Institute of Technology and Key Construction Projects of the First Class University(Phase I)of Guizhou Province in 2017-the First Class Course(Nos.2017158418 and 2017158435).
文摘The use of ethanol is a promising method to reduce the emissions of diesel engines.The present study has been based on the installation of a gasoline electronic injection system in a single-cylinder diesel engine to control the amount of ethanol entering the cylinder during the compression(while diesel has been injected into the cylinder by the original pump injection system).The injection time has been controlled by crank angle signal collected by an AVL angle indicator.In the tests ethanol and diesel each accounted for half of the fuel volume,and the total heat energy supply of the fuel was equivalent to that of the diesel under the operating conditions of the original engine.A three-dimensional combustion model of the diesel engine has been implemented by using the CFD software FIRE.Simulations have been carried out assuming uniform and non-uniform injections rate for the different holes and the different results have been compared.According to these results,a non-uniform injection rate can produce early ignition and cause an increase in the maximum in-cylinder pressure and the maximum average incylinder temperature.Moreover,in such conditions NO emissions are larger while soot emission is slightly lower.
文摘The preparation of ethanol-diesel fuel blends and their emission characteristics were investigated. Results showed the absolute ethanol can dissolve in diesel fuel at an arbitrary ratio and a small quantity of water(0.2%) addition can lead to the phase separation of blends. An organic additive was synthesized and it can develop the ability of resistance to water and maintain the stability of ethanol-diesel-trace amounts of water system. The emission characteristics of 10%, 20%, and 30% ethanol-diesel fuel blends, with or without additives, were compared with those of diesel fuel in a direct injection(DI) diesel engine. The experimental results indicated that the blend of ethanol with diesel fuel significantly reduced the concentrations of smoke, hydrocarbon(HC), and carbon monoxide(CO) in exhaust gas. Using 20% ethanol-diesel fuel blend with the additive of 2% of the total volume, the optimum mixing ratio was achieved, at which the bench diesel engine testing showed a significant decrease in exhaust gas. Bosch smoke number was reduced by 55%, HC emission by 70%, and CO emission by 45%, at 13 kW/1540 r/min. However, ethanol-diesel fuel blends produced a few ppm acetaldehydes and more ethanol in exhaust gas.
文摘为研究掺烧不同比例的乙醚对柴油机燃烧及排放特性的影响,以4190Z L C-2型船用中速机为研究对象,利用AVL_FIRE仿真软件构建燃烧室高压循环模型,在全负荷工况下对比实测与仿真缸压和放热率曲线,验证模型的准确性。在全负荷工况下,通过仿真模拟实验,在柴油中分别掺混体积分数为0%、5%、10%、15%的4种比例的乙醚,研究其对柴油机燃烧和排放特性的影响。结果表明:与燃烧纯柴油相比,使用柴油-乙醚混合燃料,缸内最大爆发压力和缸内最高温度均有所下降,对应的曲轴转角也稍有延后。增加乙醚的掺混比例,CO和NO的排放量均呈现降低趋势,碳烟排放略有增加。在反应过程中,乙醚加入延长了混合燃料的滞燃期,油气混合更加充分,放热过程稳定,提升柴油机的稳定性。当乙醚掺混体积分数为15%时,NO排放量较原机降低12.7%,CO排放量降低7.8%,碳烟排放量增大10.7%。
