乙醇/汽油混合燃料对电喷汽油机排放特性的影响

采用增氧剂乙醇替代甲基叔丁基醚，在发动机台架上研究了不同掺混比混合燃料对电喷汽油机排放特性的影响及三效催化器的净化性能。实验结果表明，汽油机掺烧乙醇后，在低转速时CO排放有所升高，而在中高转速时CO的排放改善程度较小；在所有转速条件下，THC排放量都有所降低，其中E4组（无水乙醇添加量9．826％）燃油对THC排放改善效果较明显，降低幅度接近40％，而NOx排放仅在中低转速时降低较明显。催化转化器对CO和THC净化效率分别为42％～99％、58％～93％，对NOx的催化转化率相对低一些，平均约为27％。三效催化器的转化效率与燃料中乙醇含量、汽油机转速和负荷有关。

Effect of Ethanol Anhydrous Addition into Gasoline on Regulated Emission Characteristics of an EFI Gasoline Engine

Referring to oxygen concentration in methyl tertiary butyl ether (MTBE)/gasoline blended fuels with 0, 5%, 10%, 15% and 20% MTBE respectively, ethanol anhydrous (EA) was used as a substitute for MTBE and mixed into 90# unleaded gasoline, namely E0, E1, E2, E3 and E4. The effects of EA addition into gasoline on the regulated emissions from an EFI gasoline engine and catalytic conversion efficiency were investigated. The experimental results showed that with EA/gasoline mixtures, CO emissions were increased at low speed and decreased little at middle and high speed. THC emissions were reduced under all operating conditions. When E4 was fueled, THC emissions have been decreased obviously to 40%. NO_x emissions had a great decrease at low and middle speed. Catalytic conversion efficiencies of CO and THC were from 42% to 99% and from 58% to 93% respectively. But catalytic conversion rate of NO_x only reached 27%. The efficiency of catalytic converter had relations to the speed, load of the engine and the ethanol content in the blended fuels.