乙醇/柴油混合燃料的相溶性及对发动机性能影响的研究

利用助溶剂解决乙醇/柴油的相溶性问题，讨论了混合燃料中乙醇和助溶剂添加量对相溶性的影响，并使用助溶剂体积分数为1.5%、乙醇体积分数分别为5%、10%、15%的混合燃料及 20号纯柴油（分别表示为E5、E10、E15和 E0）在发动机台架上进行了性能和排放试验。研究结果表明，柴油的烃组成是决定相分离温度的决定性因素；对全部测试油品，乙醇体积分数在10%、助溶剂添加体积分数为1.5%时，混合燃料相溶性较好。台架试验显示，随着混合燃料中乙醇掺烧比例的增加，发动机的燃油消耗率逐渐增加，而发动机的额定功率和最大扭矩逐渐降低，但最大扭矩降低的幅度较小；此外，随着乙醇掺烧比例的增加，CO比排放量减少，HC、NOx和PM的比排放量逐渐增加，但NOx和PM的比排放量增加幅度不大。10%体积分数的乙醇添加量是乙醇/柴油的最佳掺烧比。

Soluble characteristics and emission properties in diesel engine of ethanol-diesel blend fuel

The soluble characteristic of diesel-ethanol blended fuel using co-solvent was investigated and its performance and exhaust emission behaviours in a diesel engine were examined.Four ethanol-diesel fuels named as E0,E5,E10 and E15 were prepared with the content of co-solvent being 1.5% and the contents of ethanol being 0(-20# neat diesel),5%,10% and 15% by volume,respectively.It was found that the composition of various hydrocarbons in the diesel fuel exhibits significant influences on the soluble characteristic and the addition of 10% ethanol and 1.5% co-solvent in the diesel can prevent the blend fuel from phase separation perfectly.The engine tests indicated that the brake specific fuel consumption increases gradually while the rated power and the maximum torque decrease with a growth in the ethanol content of blend fuel.As to the regulated exhaust emissions,the brake specific emissions of HC,NOx and PM(BSHC,BSNOx and BSPM) increase with the ethanol content in the blend fuel,but the increments of the BSNOx and BSPM emissions are not so obvious as NOx emission.The BSCO emissions tend to reduce with an increase in the ethanol content.Overall,the ethanol-diesel blend fuel with an ethanol content of 10% exhibited the optimum performance on engine operation and exhaust emission controlling.