Research on Operation Characteristics of Compression Ignition Engine Fueled with Dimethyl-Ether/Diesel Blend

An investigation was carried out to determine the miscible properties of DME with diesel and the spray characteristics of D20 blend.The engine performances,such as power output,fuel economy,and emission characteristic,were studied when the engine was fueled with D20 blend.Experimental result shows that the vapor pressure of DME blends is lower than that of pure DME at certain temperatures,which helps eliminating the vapor lock in the engine fuel supply system.Under the same ambient pressure,D20 blend exhibits shorter spray penetration and larger spray angle in comparison to pure diesel fuel,which is beneficial to the mixing of injected fuel with surrounding air.In addition,engine test result also indicates that the engine performance of DME blend engine is better than that of original diesel engine,the power output can increase,the lowest specific fuel consumption can reduce by 4.5%,soot emissions can decrease by more than 70%,and NOx emissions can decrease by 30%～50%.